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Aside from DES, has the NSA ever strengthened algorithms?
When DES was originally developed, the NSA changed the s-boxes. For decades, people thought that their changes introduced a backdoor, but then it was discovered that their changes actually strengthened DES against differential cryptoanalysis.
The NSA is well known for it's placement of backdoors into algorithms. In a way, they did this with DES when they reduced its key strength, but Dual_EC_DBRG is the most famous contemporary example of this.
Are there any other examples of the NSA strengthening non-classified cryptographic algorithms?
des history nsa
neubertneubert
$\begingroup$ I guess SHA-0 to SHA-1 would probably apply here $\endgroup$
– Richie Frame
$\begingroup$ Reducing the keysize of DES is more of a frontdoor than a backdoor, since they make no attempt to hide that fact. Also it's not really that the NSA changed the keysize so much as they told everyone that they keysize must be 56 bits or less. IBM simply went along with it. $\endgroup$
– forest
$\begingroup$ @forest: it appears that the NSA wanted 48-bit DES, IBM wanted 64-bit or more, and 56-bit was a compromise. See this for what I could gather on that. $\endgroup$
– fgrieu ♦
$\begingroup$ "When DES was originally developed, the NSA changed the s-boxes"; actually, from what I heard (Coppersmith), IBM originally proposed the sboxes, and the NSA did not change them. Now, that talk by Coppersmith was circa 20 years ago, so my memory might be a bit foggy; I do believe he stated that. $\endgroup$
– poncho
Almost certainly, at least once.
It is a mistake to think of the NSA merely as a SIGINT (signals intelligence) operation. They also do defense, especially at the Information Assurance Directorate (IAD), as seen on this link to the NSA:
IAD has developed partnerships with government, industry, and academia in order to commercialize Information Assurance (IA) technology and products. By setting standards and encouraging vendors to build to those standards, IA ensures that secure devices and networks are not only available to customers, but keep pace with current technologies.
What is information assurance (IA)?
IA identifies and corrects security vulnerabilities before our adversaries exploit them...
In 2011, the Cybersecurity Operations Center (this links to the NSA) was created.
The Cybersecurity Collaboration Center is NSA's groundbreaking hub for engagement with the private sector. These partnerships help NSA to prevent and eradicate foreign cyber threats to National Security Systems (NSS), the Department of Defense (DoD), and the Defense Industrial Base (DIB).
On this page, the CCC describes its job, and among the points is this:
Develop guidance and technologies [boldface mine] to improve the security and capabilities of cross domain solutions
The case in point--that shows what must have been NSA involvement--is the identification and elimination of a weakness in the Secure Hash Standard (SHS).
On July 11, 1994, the NIST proposed an interesting revision to FIPS 180, about the Secure Hash Standard:
A revision of Federal Information Processing Standard (FIPS) 180, Secure Hash Standard (SHS), is being proposed. This proposed revision corrects a technical flaw that made the standard less secure than had been thought. The algorithm is still reliable as a security mechanism, but [sic] the correction returns the SHS to the original level of security.
FIPS PUB 180-1 it explains:
A circular left shift operation has been added to the specifications in section 7, line b, page 9 of FIPS 180 and its equivalent in section 8, line c, page 10 of FIPS180. This revision improves the security provided by this standard. The SHA-1 is based on principles similar to those used by Professor Ronald L. Rivest of MIT when designing the MD4 message digest algorithm 1, and is closely modelled [sic] after that algorithm.
NSA surely had a hand in this, and it was likely done to protect users (or was it?). Given the mandated roles of the IAD and CCC, and especially that the CCC develops technologies, it is reasonable to conclude that these technologies are sometimes shared--in order to protect U.S. critical infrastructure and correct security vulnerabilities. As far as the question goes, about strengthening algorithms, there is at least this one instance that we know about since it is unclassified.
PatriotPatriot
Not the answer you're looking for? Browse other questions tagged des history nsa or ask your own question.
Purpose of DES parity bits
Duration for attacking Two-Key Triple-DES Encryption using all RAM ever built?
Has a Two Key TDES encryption ever been successfully attacked?
Has the Linear Congruent Generator ever been used in any of the early crypto algorithms?
What are the separate single DES keys from a triple DES key?
Why did the NSA create SHA?
NSA removed EC-256 and SHA-256 from CNSA recently--should we be alarmed by this?


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Home Skin Diseases
What is Eosinophilic Fasciitis: Causes, Symptoms, Treatment, Prognosis
What is Eosinophilic Fasciitis?
Eosinophilic Fasciitis is an extremely rare pathological condition in which the tissues beneath the skin get inflamed, swollen, and painful and with time as the disease condition progresses make the arms and legs extremely hard and not as supple.
Eosinophilic Fasciitis gets its name from the increased number of eosinophils that is present in individuals with Eosinophilic Fasciitis, and the fascia which gets inflamed and hard as a result of this buildup of eosinophils. Eosinophilic Fasciitis damages the connective tissue to some degree as well.
It can also be caused due to inflammation when some part of skin is removed for testing purposes for some other medical condition. Majority of the cases of Eosinophilic Fasciitis can be successfully treated by administration of steroids. There is no known cause for Eosinophilic Fasciitis but in most of the cases males between the ages of 30 and 50 tend to get Eosinophilic Fasciitis.
What are the Causes of Eosinophilic Fasciitis?
As stated, there is no known cause of Eosinophilic Fasciitis. It is just that there is a gradual buildup of eosinophils in muscles and tissues causing them to become hard. Certain allergic reactions have been linked to increased number of eosinophils but it is yet to be confirmatively proved to be a cause for Eosinophilic Fasciitis.
What are the Symptoms of Eosinophilic Fasciitis?
The initial clinical presentation for Eosinophilic Fasciitis is pain, swelling, and inflammation of the skin especially in the inner half of the arms and the front part of the legs. In some cases, the skin surface of the chest and abdomen may also be affected due to Eosinophilic Fasciitis.
In the first phase of the disease process, the symptoms may be felt after a strenuous activity which gradually progresses to having symptoms even at rest as well. As the condition progresses, the skin starts to become hard making it difficult for the individual to move the hands and legs fluently.
Ultimately, the arms and legs may freeze in certain awkward position from which it may become very tough for the individual to get it back to normal. Unintentional weight loss and persistent fatigue are also quite common symptoms seen in Eosinophilic Fasciitis. There may also be muscle and joint pain.
Carpal tunnel syndrome is also said to occur in some cases due to Eosinophilic Fasciitis. In some cases of Eosinophilic Fasciitis, the RBCs and platelets tend to become very less causing the individual to feel fatigued persistently and even bleed easily. Some cases of aplastic anemia and abnormally low platelet count have also been noted with Eosinophilic Fasciitis.
How is Eosinophilic Fasciitis Diagnosed?
The symptom presented by the patient to the treating physician is a virtual give away that the patient is suffering from Eosinophilic Fasciitis. For confirmation, the physician may do a blood test which will show increased levels of eosinophils in the blood and the level of erythrocyte sedimentation rate is also increased indicating inflammation. A biopsy of the affected skin and fascia is then taken to confirm the diagnosis of Eosinophilic Fasciitis.
How is Eosinophilic Fasciitis Treated?
The front line and most successful treatment for Eosinophilic Fasciitis is administration of steroids. The treatment for Eosinophilic Fasciitis should be started as soon as the diagnosis is made to prevent any scarring, loss of tissue and contractures from developing. The steroids are given in tapering doses but may need to be continued for up to may be even 3-5 years for complete treatment of Eosinophilic Fasciitis.
NSAIDs are also quite effective in calming down pain and inflammation caused due to Eosinophilic Fasciitis. If an individual has gone on to develop contractures and carpal tunnel syndrome then surgery may be required to correct those conditions caused due to Eosinophilic Fasciitis.
The patient will be closely monitored throughout the treatment process with periodic blood work so as to prevent any blood disorder from developing, and if present can be treated effectively, as a result of Eosinophilic Fasciitis.
What is the Prognosis of Eosinophilic Fasciitis?
In majority of cases, a patient can be successfully treated from Eosinophilic Fasciitis in a span of about five years, although the chances of the symptoms recurring are quite high. In some cases, symptoms may persist for a longer period of time even after timely treatment of Eosinophilic Fasciitis. If the condition is not treated adequately and the patient goes on to develop blood disorders then the overall prognosis becomes severely guarded in terms of recovery from Eosinophilic Fasciitis.
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redpajama_set_name: RedPajamaCommonCrawl


DENVER � An immigration strategy hatched by a Denver-based� foundation that relies heavily on the private sector is gaining interest nationally since Republican presidential candidate Newt Gingrich endorsed it during a debate last month.
�The strategy, however, provides no path to citizenship.
� �We�re seeing signs that it�s picking up steam,� said Shari Williams, executive director of the Vernon K. Krieble Foundation that generated and promotes The Red Card Solution.
� Gingrich raised eyebrows among his conservative base when he publicly embraced The Red Card Solution. It strays from the deportation philosophy and welcomes foreigners, albeit temporarily.
� The plan proposes a microchip-equipped card as the key to employment in the U.S. for foreign workers. Employment agencies in other countries would act as the conduit between American businesses looking to fill positions and aspiring guest workers desiring employment in this country.
� As part of the credentialing process to receive a card, background checks would be coordinated with the U.S. Department of Homeland Security to assure the visiting foreigners are not a threat.
� The cards would serve as a tool to check workers� status in the country and verify their identities. The cards would be valid only for the duration of employment. When a job ends, so does permission to remain in the country. Guest workers would be required to return to their native lands.
� The concept began with the foundation�s president, Helen Krieble, whose late husband is the foundation�s namesake. She operated an equestrian center near Parker, south of Denver, that relied on immigrant labor.
� �It really came out of the fact that she�s an employer who wants to meet the rule of law,� Williams said.
� The complexity of navigating work visas and other aspects of immigration law struck Helen Krieble as overly burdensome for employers and workers alike. She sought a simple fix, and Williams said she found it in The Red Card Solution.
� Krieble toted the concept around in her own head for half a decade, then five years ago the foundation � which promotes ideas, not legislation � published a paper unveiling the plan.
� Modest attention followed until the past couple of years, when polls started showing growing support for guest worker programs. Then Gingrich�s take on the plan catapulted it into the national spotlight.
� Inquiries from organizations that closely follow the immigration debate and lawmakers nationwide are flooding the foundation.
� �I know for certain it�s gaining traction nationally,� Williams said.


Thermographic Testing at Infrared Testing Inc.
Infrared Testing, Inc. (ITI) is a leading thermographic inspection company with expertise in helping to prevent and control property loss. Since the company's founding in 1990, ITI's certified infrared thermographers have conducted over 350,000 facility inspections in more than 50 countries.
We specialize in designing inspection programs to meet each client's needs by incorporating infrared inspections into the company's corporate risk management, loss control, and/or predictive and preventive maintenance programs. Our reports include potential annual electrical savings dollar value based on our survey findings.
With a preventive maintenance program using infrared technology, we uncover the mysteries lying deep within the housings of equipment and the walls of a facility to prevent unexpected problems. Manned inspections often overlook faulty fuses, loose connections and overloaded circuits not visible to the human eye.


I frequently hear coin collectors refer to the $20 gold Saint Gaudens double eagle as the most beautiful U.S. coin. While there are a couple of other coins that I believe have a shot at that title, I have to agree that this coin is among the contenders.
The St. Gauden's General Sherman statue in Central Park used as the model for the $20 gold double eagle design in 1907.
The double eagle design by sculptor Augustus Saint-Gaudens was a result of a complete redesign of U.S. coinage at President Roosevelt's request. Unfortunately, Augustus Saint-Gaudens died shortly after the first of his double eagles were minted.
The 1911-D/D $20 gold double eagle in The Arlington Collection is an interesting Doubled-D variety, but it is not particularly rare.
This is a nice gem example with full mint luster on both sides of the coin. The coin has a nice light green-gold color to it and it makes it a very appealing type coin.
Many thousands of mint state examples of this date have abrasions on the knee and breasts of Miss Liberty, which in my opinion negatively affect the eye appeal of those coins. This example has none of those abrasions and is simply a beautiful coin.


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REVIEW: SD bands shine at SXSW
The trip to South by South West (SXSW)-an annual film, interactive and music festival and conference where over 2,000 of independent music's brightest new talents perform in over 90 venues in downtown Austin-isn't exactly a piece of cake.
It's the whole cake, and you have to finish it all before it gets taken away from you.
As a band playing SXSW, the first hope is that everyone in your band survives. At best, you want to leave with a lot more of the "people who matter" (whoever you think they may be) knowing your band exists.
Bands can expect, without uncertainty, to burn the candle from both ends for 4 days and nights with thousands of other bands from around the world while drinking copious amounts of free beer.
Lots and lots and lots of free beer.
Driving to Austin seems like an easy task but whether you drive with a few friends in a car, or with six guys in a van, the full-day drive East is scenic – for about 2 hours – and then it becomes uncomfortable and depressingly uneventful except for the occasional dramatic scene at a Border Patrol checkpoint.
Upon arrival in Austin, the next four days take place over what feels like 24 hours.. There are people everywhere. In the parks, in the streets, in the venues, on the freeways, everywhere.
And again, lots and lots and lots of free beer.
Unable to discern fan from band, local from tourist, or even left from right, you just sort of get swept up in a storm of madness until you magically end up back in your car or van-dirty, sweaty, achy, drunk and broke – heading back toward America's Finest City.
But despite the drive and the drinks, San Diego did pretty well in showing itself off in "The Live Music Capital of The World" as 10 local artists or bands made the long trek.
Some local bands playing "official" SXSW showcases for the first time (Gary Wilson, In Fear and Faith) while some bands went to Austin to play up to half-dozen shows each at hundreds of the "unofficial" parties put on by local residents and businesses.(Little Hurricane, Silent Comedy, Writer).
Bands like The Black Heart Procession, Gun Runner, the Hot Moon, and Maren Parusel played multiple showcases, including a Saturday night Official SXSW Showcase at Maggie Mae's and several day-parties organized by San Diego's Requiemme Management.
Last but not least, San Diego troubadour, story-teller, songwriter and SXSW veteran and favorite Steve Poltz (known nationally as "the guy who dated Jewel and co-wrote some of her hit songs"), played five different times this year, including an official showcase at Continental Club.
Fortunately for our fair city, all of the bands made it through the storm alive and are no doubt eager for what future opportunities playing SXSW might bring.
Like I said before, SXSW is no piece of cake, it's a whole cake, and San Diego can be proud that the bands that represented the city certainly have one hell of a sweet tooth.
CTTV/NEWSCENE
VIDEO: Masks coming off at San Diego City College, SDCCD amid increased COVID-19 cases in county
VIDEO: City College transfers have more time to submit Cal State, UC applications (updated)
SDCCD chancellor, leadership outline priorities at City College forum
Masks not required at SDCCD, City College starting Dec. 19
Why do City College students vote the way we do?
Biden helps get out the vote at MiraCosta College
VIDEO: Make your voice count — Cast your ballot before Nov. 8
UPDATED: Take 5 minutes to complete new federal student loan debt relief application (we show you how)
CITY TIMES SOUND
VIDEO/RADIO: Patrick Henry to restore some cut advanced classes
City student, faculty among plaintiffs suing SDCCD over COVID-19 requirements


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Squid Game Theory: How Are Employees Selected?
January 3, 2022 by Susan Hall
A theory concerning the hour series Squid Game has ignited the web in the last few days. Some netizens believe they have found out how the game's employees, those dressed in red suits, are selected.
• Read also: Here's where to find the best Squid Game costumes for Halloween
• Read also: Squid Game Could Be The Greatest Series In Netflix History
Before going into details, it should be noted that the following information could contain spoilers. Be warned!
The South Korean series is enjoying huge success right now. # 1 on Netflix and source of several memes, Squid Game has been combed through by Internet users, who share several interesting theories. There is one viral theory right now that has caught our attention a little more than the rest: the one about the selection of the game's employees.
The theory seems to have taken shape mainly on TikTok. Several internet users believe that a scene from the first episode, where the character of Gi-hun plays a game of Ddakji with a mysterious man in the subway, explains the selection of players and employees of the survival game.
In this scene, Gi-hun must choose between two cards: one red, and one blue. According to the theory, the people who choose the blue card will be players, dressed in a turquoise ensemble once in the game, and those who choose the red card will be employees, dressed in red.
It's hard to say if this idea really holds, because there is still a good difference in color between the blue card and the clothes of the players. Employees, on the other hand, also seem to be familiar with their roles and tasks. Because they are wearing masks, however, it is not entirely clear what they are feeling.
Image courtesy Netflix
It's not totally unrealistic, though. There's one scene in particular where an employee is unmasked, and he's told he's just a kid. Are the employees therefore also victims, selected and imprisoned by a brutal game? After all, the game is a constant reminder that everyone in the room is equal. So the employees may be in a "similar" situation to the players.
Rather, other theories on TikTok believe that these mysterious people in red clothes are former gamers, who are unable to manage their lives after winning the jackpot. This theory is based on the possible behaviors of Gi-hun, but the indices are rather weak.
While none of this has been confirmed, we're pretty confident that there will be several other interesting theories over the next few weeks, due to the series' immense popularity!
Squid Game is available on Netflix.
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Categories Entertainment Tags employees, Game, Selected, Squid, Theory Post navigation
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BOTHELL, Wash. — A local professor is receiving praise for holding an extra finals exam session at night, giving his Muslim students a chance to eat following Ramadan fasting.
Dr. Bryan White, a biology professor at the University of Washington Bothell, is holding two exam times, allowing students to take their final exams after sundown so they'll be well-nourished.
The extra exam session is scheduled for June 8 from 10 p.m. to midnight. Students can choose that exam, or the one scheduled for regular class time, which is 8:45-10:45 a.m.
Both exam times are open to all students.
Local groups such as "MAPS – Many Cultures, One Community" have praised White.
White told Q13 News the idea of an extra exam time came after talking to some of his Muslim students last year. Some of his Muslim students, White said, performed worse on the final exam than he expected they would. When he asked why, at least one student told him she had trouble concentrating because she was so hungry.
"She was finding it hard to concentrate and study because of fasting in observance of Ramadan," White said.
Ramadan is observed by Muslims worldwide and lasts 29 days. Muslims fast from dawn until sunset, and refrain from consuming any food or drink.
When White learned Ramadan would occur during finals week this year, he decided to schedule an extra test time as a "simple gesture" for his Muslim students. He wanted everyone to be firing on all cylinders when they take the test, which he said is crucial for continuing in the field of biology.
White said as a biologist, he's ever-aware of the relationship between food and mental functioning. He often provides food during his tests, he said, and knows he responds better with a full stomach.
"I do my best when I have sugar in my system," White said.
Other professors at UW Bothell applauded White's decision. Two other biology professors will hold a night time test in conjunction with White's.
White said about 10 percent of his students have chosen to take the late test. In the end, he said, it's about wanting his students to perform their best.
"If they didn't eat and are struggling with concentration, I just want them to perform as well as the can," White said.


Posted on October 1, 2014 May 10, 2017 by admin1234!
Breaking up doesn't mean that no more love is left; it's more of trying to save the love that's left. When we suffer a loss, a break up, a painful change in our lives, we need to remember to take all the time we need to heal emotionally. Moving forward and getting back on track with our lives doesn't take a day. It takes a lot of small steps to allow us to break free from our broken self and move on.
Relationships nowadays are shorter than courtship. Why? Because some guys changes when they got the girl they want. As other said "Relasyon ang pinapatagal, hindi ang panliligaw." Yes it's true. Kasi ano pang silbi ng taon mo'ng panliligaw kung pang isang linggong kaligayahan lang pala? Niligawan mo ang babae, kaya dapat panindigan hanggang dulo. Pagdating sa tunay na pagmamahal, there's no such word as flaws and imperfections.
After a breakup, it takes a couple weeks for the fog to settle, but it's always a period of self-priority and growth. Hayaan mo kung may nakita na kaagad sya na iba. Wag mong panghinayangan ang mga taong ikaw mismo ang sinayang dahil at the end of the day babalik at babalik yan, and when that time comes, wala na syang babalikan. As they say, the best revenge is living well.
Breaking up is a natural evolution when you try to figure out what you want in life. If you're with an individual who isn't moving in the same direction and at the same rate that you are, it ain't going to work. Breaking up is not a stupid thing; instead it makes you a better person and realize your mistakes. Just.. Wake up!
Break ups are for hurting of course. It's natural. But it'll mold you to become a better person. learn from it. It's okay to feel like you have messed up – accepting responsibility for your mistakes or shortcomings is healthy. On the other hand, you must also accept that you are a good person, and that you did your best and you're not the only one who made mistakes. Acceptance is the key to being able to start moving on.
Maybe God wants us to meet a few wrong people before finding the right one, so that when we finally find the right one, we will know how to be grateful. Don't settle for those person whom you known in the first place will break your heart.
Understand that there is no benefit in holding on to heartache, bumangon ka! Hindi pa end of the world. Marami ka pang pwedeng gawin, hindi lang pagmumukmok. Realize that although it is over, your relationship with that person was unique and special in a lot of ways. You can congratulate yourself for being brave enough to take a risk and fall in love, and encourage your heart that even though love didn't work out this time, there will be a next time. Cheer Up and smile like nothing happens!
There is nothing sadder in this life than to watch someone you love walk away after they have left you. To watch the distance between your two bodies expand until there is nothing left but empty space… and silence. Crying all night is okay. In fact, studies show that crying over your breakup all night well help you get over your breakup faster.
The hardest part of a breakup, is not going with the routine you had with your ex. Finding other things to replace the dates, the phone calls, the constant texting, the urge to see each other, the promises made, the laughter, the intimate moments, the I love you's, the I miss you's, the comfort and the love that you both shared.
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A method for measurement of the size distribution of particles suspended in a gas or in a liquid. The particle suspension is illuminated by a collimated beam of colored light, which is produced by passing a collimated beam of substantially white light through a spectral filter which has spatial sections of narrow spectral passband in the blue, green and red. Part of the light scattered by the particles is collected by a lens and is passed through a spatial filter placed in the focal plane of the lens. The light transmitted by the filter is measured by a photodetector. The photodetector output is measured as different spatial filters are switched in place. A computer, microprocessor, or analog device acts on the measured values and produces the particle size distribution as an output. The data reduction algorithm consists of a linear transformation of the measured data vector, followed by the construction of a linear combination of basis functions for the size distribution. The spatial filters consist of color transparencies with non-uniform spatial transmittance functions in the blue, green, and red. The average scattering angle is not restricted, but for broad polydisperse particle distributions near back scatter is preferred, in order to avoid an ill-conditioned data reduction problem. One of the spatial filters has uniform transmittance for the purpose of back ground light subtraction, and to provide a bias in order to allow effectively indefinite filter transmittance functions.
This invention was made during the course of work performed under a contract with the Office of Naval Research. The invention pertains to the rapid measurement of the size distribution of particles suspended in a gas or in a liquid. For simplicity the discussion in the present section is made to refer to the case of water drops suspended in air. In most of the known instruments which are presently available for measurement of drop size distributions, sample air is moved through a small highly illuminated volume of space, and light scattered by the individual drops, as they move in a single file through this volume, is measured by a photodetector. The drop size is determined from the intensity of the electric pulse out of the photodetector. This method suffers from a number of deficiences, notably the edge effect, the velocity effect, and counter swamping. The edge effect arises because drops which pass through the scattering volume near the edge of the illuminating beam are illuminated less and therefore scatter less light. This causes the instrument to undersize the drop. The velocity effect arises in airborne applications, where the cloud drops move rapidly through the scattering volume. The resulting short detector pulse duration requires somewhat different electronics parameters than those used for terrestrial laboratory work, where the drop velocity is small. As a consequence, laboratory calibration of the instrument, unless it is done in a windtunnel, is of limited utility for airborne measurements. Counter swamping may occur when drop size distributions are measured in dense clouds aboard a fast flying aircraft.
The measurement method comprised in the present invention suffers from none of the deficiencies discussed. Instead of counting and sizing individual scattering events, the instrument looks at a sizeable volume of cloud (from about one liter to several cubic meters) and it processes the light scattered from all drops in this volume collectively. This makes it possible to measure drop size distributions in clouds, fogs, or in laboratory cloud chambers in situ, without disturbing the cloud. Furthermore, it becomes possible to perform bulk measurements, in which average drop size distributions in a large volume are determined rapidly.
In practice, the light scattered by the multitude of individual particles adds incoherently. In the case of spherical particles, each particle scatters light in its characteristic Mie intensity pattern; these Mie patterns superimpose and give rise to a scattered light intensity which is a certain function of scattering angle. It is the object of the present invention to provide a means for determining the particle size distribution from this scattered light function.
Under circumstances often encountered, the conversion from the scattered light function to the particle size distribution constitutes an ill-conditioned data reduction problem, which results in low instrument accuracy. It is a further object of the present invention to circumvent this problem.
The measurement of the scattered light function may be done by means of an array of photodetectors, as in the apparatus of Malvern Instrument, Ltd., of Malvern Worcestershire, England. This requires the photodetectors to be small solid state devices, such as photodiodes, and this restricts the detectivity of the instrument such that only relatively dense particle suspensions can be measured accurately. Using photomultiplier tubes instead of photodiodes would result in a much increased instrument sensitivity, but use of an array of photomultiplier tubes would be prohibitive in cost and size. Therefore, there is merit in a method which requires only a single photodetector for the measurement of light scattered by the particles. For this photodetector, a photomultiplier tube can then be used.
It is a further object of the present invention to determine the particle size distribution by using a single photodetector for the measurement of the light scattered by the particles.
There are several situations in which it is desirable to utilize scattering angles near 180.degree., i.e., near backscattering. Such an arrangement makes it possible to have the light source and detector in the same general location, and yet measure particle size distributions in a large volume or at rather large distances from the apparatus. It is a further object of the present invention to provide a method for determining particle size distributions which can be used with near backscattered light.
Often, there is undesirable background light in the form of daylight, or from light sources extraneous to the instrument. In cloud chamber work, the illuminated cloud drops inside the chamber scatter light in all directions; some of this light is reflected by or scattered off the chamber walls, and this results in undesirable background light which enters the instrument. It is a further object of the present invention to provide means to effectively subtract background light in the instrument process.
It is yet another object of the present invention to provide a means of measuring particle size distributions in real time.
By way of summary, the objects of the invention are achieved by passing a collimated beam of colored polarized light through the particle suspension and by collecting part of the light scattered by the particles located in a portion of the illuminating beam by a photodetector, after the light has passed through a lens and through a spatial filter placed in the focal plane of the lens; this spatial filter is a color transparency. Different spatial filters are brought into position behind the lens in quick succession, and the sequence of measured photodetector outputs is acted upon by a linear transformation, followed by the formation of a linear combination of basis functions for the particle size distribution, executed by a computer, microprocessor, or an analog device. The colored collimated light beam which illuminates the particle suspension is produced by passing a collimated beam of substantially white light through a spectral filter which consists of 3 spatially separated sections which have narrow spectral passbands respectively in the blue, green, and red.
FIG. 10 shows the presently preferred embodiment, employing two-color light for the illuminating beam, and further employing near-back scattering, and a film strip for switching a plurality of spatial filters.
Referring now to FIG. 1, a light source 11 produces a collimated or nearly collimated beam 12 of nearly-monochromatic polarized light, which illuminates the particle suspension. A lens or lens system 13 processes light scattered by the particles located in the volume 12b of the beam 12 inside the cone 14, the latter constituting the field of view of an optical configuration consisting of lens 13 and an image window 15, located in the focal plane 16 of lens 13.
In this specification, the term "focal plane" is defined as the plane which sharply images objects at infinity.
A polarizing element 17 is placed in the path of scattered light, preferably but not necessarily between the lens 13 and image window 15. A perfect lens 13 would map incoming light rays located inside cone 14 onto points in image window 15. Therefore, part of the light scattered by an angle .theta. by all particles in the volume 12b is imaged onto a curve in window 15. As a consequence for spherical and monodispersed particles, the light intensity in image window 15 will be distributed according to a Mie intensity pattern.
A set of (N+1) spatial filters 18 is mounted on a disc 19 in plane 16. Arrangements are made such that, in time, different spatial filters are switched into the position of window 15.
An alternate embodiment of the switching concept consists of a filmstrip 19a, the frames of which are the individual spatial filters. The filmstrip is moved past the window in step-wise motionpicture fashion. The filmstrip (FIG. 2) can be looped, without beginning or end, if preferred.
There is the option of chopping the beam 12 of light by a chopper 22, and using synchronous detection in a manner which will be evident to those skilled in the art.
There is the further option of having either disc or filmstrip move continuously, and to flash the light source 11 synchronously with the filter position. A gated amplifier or integrator can then be used in the signal processing.
Each spatial filter consists of a transparency, the transmittance of which is a function of location on the transparency. Behind the image window 15 and the spatial filter 18 there is a photodetector 20, which is usually a photomultiplier tube. With the i.sup.th spatial filter in place, the signal from the photodetector 20, usually after amplification and integration, (possibly gated), is measured and serves as input s.sub.i for a computer 21. In the present context, the computer 21 may be a computer, a microprocessor, or an analog device, such as a CCD or CTD. There are N+1 different spatial filters on the disc 19, and hence, there are N+1 signals s.sub.i. The computer 21 is programmed or arranged such as to execute a linear transformation of the data sequence S.sub.i, i=0,1,-N, by means of a matrix T.sub.ij, which is present in the computer, or embodied in an analog device, in a manner as will be evident to those skilled in the art. The result of this linear transformation is the sequence ##EQU1## j=1,-N. As a further action of the computer, the sum ##EQU2## is computed, where the n.sub.j (a) are N basis functions for the particle size distribution function, a being the particle radius, or some other particle size characterizing number. The function n(a) is the particle size distribution which is the object of the measurement. It may be displayed, printed, or used as input for further calculations in a manner evident to those skilled in the art. The number b.sub.o is not used in the particle size distribution calculation (2), since things are arranged such that b.sub.o is a measure of the background light, and such that the b.sub.j,j=1,-N, are not influenced by the background light. Essential to this arrangement is the use of one spatial filter, say with j=0, which has uniform transmittance.
The action of the filters may be understood as follows. Suppose that the cloud consists of drops of a uniform size. If for that case the filter 18 in the image window 15 would be replaced by a screen, the light processed by the apparatus would illuminate this screen with a non uniform intensity, showing light and dark bands, which are called a Mie pattern. The Mie pattern depends on the scattering angle range in the field of view of the cone 14, and it also depends on the size and the refractive index of the scattering cloud drops. If now different filters are switched into place, maximum light would get passed by a filter which has a transmittance pattern which precisely matches the MIE pattern of the incoming light. In this manner, the Mie pattern of the light coming into the window 15 is recognized, and the drop size is inferred. For a cloud with a mixture of drop sizes, the algorithym discussed unravels the separate contributions by the Mie patterns belonging to the different drop sizes to the total light intensity distribution in the window. It is possible to use filter transmittance distributions other than Mie patterns belonging to single drop sizes, by taking linear combinations of such Mie patterns for different sizes.
One then has ##EQU8## where C.sub.ij.sup.-1 is the inverse of C.sub.ij. The particle size distribution is found from ##EQU9## The correlation V.multidot.V.sub.j is implemented in the present invention by passing the scattered light through lens 13 and through the j.sup.th spatial filter 18 with transmittance V.sub.j in focal plane 16 of lens 13. The light incident on the filter has the intensity distribution V. The total light intensity transmitted by the filter is V.multidot.V.sub.j C.sub.ij.sup.-1 is essentially the instrument matrix T.sub.ij of (1); further discussion clarifying the role of i=0 or j=0 follows.
Hence, this embodiment gives a shorter computer calculation of the coefficients b.sub.i of expansion of the particle size distribution n(a) in terms of the basis functions m.sub.i (a), i=1,-N.
It will be evident to those skilled in the art how to apply this procedure to the case in which the background light illuminates window 15 in a non-uniform manner, and a 0.sup.th filter with an appropriate non-uniform transmittance is used for the implementation of indefinite filter transmittances. The description above has been given in terms of water drops in air. It applies as well to other spherically symmetric particles, suspended in a gas or a liquid except that certain ratios of refractive index of the particles and the suspending medium may favor near forward scattering rather than near backscattering. In such cases, the scattering angle range must be appropriately adjusted, but the method of measurement and date reduction remains the same. The method also applies to the case of non-spherically symmetric particles suspended in a gas or liquid, possibly with some degradation of performance of the instrument. The particles may be biological cells, bacteria, or other biological organisms, and the invention may be used to determine the concentrations of the various species of cells, bacteria, organisms, or particles which are present in a sample. The particles may be suspended on a transparent slide which is illuminated by the light beam, instead of being suspended by a gas or a liquid in the bulk.
There are various options concerning the polarization of the beam 12, and the polarizing element 17, as follows. The instrument will work with an unpolarized light source 11, and without the polarizing element 17. In fact, this is the preferred polarization mode for very near forward scattering or very near backscattering, i.e., where the intensities of the scattered light in both polarized directions are substantially the same. For scattering angles not very close to 0.degree. or 180.degree., an improvement in instrument performance is achieved by using a light source 11 which is polarized (E direction) perpendicular to the plane P through the illuminating beam axis and the optical axis of the lens. The use of a polarizing element 17 is then optional; if used, the polarization direction should be perpendicular to the plane P. As an alternative, an unpolarized light source 11 can be used, together with a polarization element 17, polarized perpendicular to the plane P. As a further alternative, the light source 11 may be polarized in the direction of P, and there is then again the option of using a polarizing element 17; if used, the element 17 should be polarized in the direction of P. As a further alternative, an unpolarized light source may be used, with element 17 polarized in the direction of P.
A modified instrument which is particularly suitable for use in clouds or fog is shown schematically in FIG. 2. In this case, near backscattering is used, making it possible to have light source 11 and detector unit close together while sampling a substantial volume of cloud or fog. The element numbers are the same as in FIG. 1, with the exception of the embodiment of the set of filters, which now is in the form of a filmstrip 19a looped and therefore without end. It is important that either the illuminating light intensity in beam 12 is very nearly the same from frame to frame exposure of the filmstrip, or else that the variation of this light intensity is measured accurately. It will be evident to those skilled in the art how to achieve this objective, if necessary by the use of an auxiliary photodetector which measures the illuminating light intensity.
FIGS. 3-7 show examples of negatives of transmittance functions for spatial filters for use in FIG. 1 with scattering angles near 90.degree.. These functions have been generated by a computer-driven plotter, from a calculation of Mie intensities for water drops in air. In these plots, the dot density along vertical lines is proportional to the average filter transmittance along vertical lines. In this particular example, the average scattering angle is 90.degree., and the coarse-grained average filter transmittance is approximately constant along vertical lines. For average scattering angles different from 90.degree., the filter transmittance is constant along curves which are conical sections of constant scattering angle .theta..
Another method for the construction of the filters consists of making a picture in the form of a slide, of a semi-transparent sheet assembly, which is illuminated from the opposite side of the camera, where the sheet assembly consists of strips of semi-transparent material such as paper, put together in layers in such a manner as to produce an assembly with the desired transmittance pattern.
Yet another method for the construction of the filters consists of producing a cloud with uniform drop size, or with a certain desired drop size distribution, and using a camera instead of the assembly 13, 18, 19 and 20, in such a manner that the camera lens is identical to the lens 13, and is placed in the position of lens 13 and such that the camera film window coincides with the image window 15. Using the proper exposure time, the picture produced in this manner, in the form of a slide, will have the proper transmittance pattern. A preferred method for the construction of the filters consists of controlling a camera orientation by means of two computer-driven angular positioners, and illuminating the camera lens with a fixed collimated light beam, which passes through a computer-controlled shutter. Alternatively, the intensity of the light beam may be modulated by the computer.
When a polarizing element is placed in the path of the scattered light, it may be placed on either side of the lens, preferably ahead of the spatial filter.
Chopping or flashing the light source is useful but not essential. A steady light source can be used. However, significant advantages are obtained by providing light intermittently, for example improvement in the signal to noise ratio, discrimination against background light, and discrimination against dc output voltage drift of the amplifiers behind the photodetector.
The accuracy of instruments of the type discussed above may be further improved by using multiple-wavelength light and colored spatial filters, in a manner as described below.
Eq. (23) may be rewritten as ##EQU18## is seen to serve as a metric in the Hilbert space of square integrable particle size distributions n(a); in fact, (25) may be seen as the scalar product m.sub.i .multidot.n.sub.j in that Hilbert space, using the metric (26).
The data reduction algorithm (13) involves the inverse C.sub.ij.sup.-1 of the matrix C.sub.ij. Therefore, the degradation of the signal to noise ratio in the data reduction will depend on the condition number of the matrix C.sub.ij (defined as the ratio of maximum to minimum absolute values of the eigenvalues). In turn, this condition number is influenced by the condition number of the metric g(a,a'). Eq. (26) shows that this metric is just the correlation (over the interval .theta..sub.1, .theta..sub.2) of the differential scattering cross sections M(.theta.,.alpha.) and M(.theta.,.alpha.'). This correlation has a peak for .alpha.'=.alpha., but there exist secondary correlation peaks as well for certain values of .alpha. and .alpha.'. This may be seen from FIG. 8, which shows the differential cross section M(.theta.,.alpha.) for the perpendicularly polarized component of light scattered by water drops. In this figure the symbol A is used for the scattering parameter, instead of .alpha.. The Mie function M(.theta.,A) is plotted in the form of contour lines as function of the scattering parameter A and the scattering angle .theta.; the numerical values for the contours shown are ##EQU19## where i.sub..perp. is the perpendicularly polarized scattered light intensity. In this case, one has .theta..sub.1 =145.degree. and .theta..sub.2 =152.degree.. FIG. 8 may be seen as a topographic map of terrain with mountains, lakes, valleys, ridges, and canyons. It may be seen that the ridge-like mountain at about A=11.4 is quite similar to the ridge-like mountain at about A=16.3; this similarity extends at least over an interval .DELTA.A.apprxeq.1 to the right. It follows that the correlation (26) has a secondary peak for .alpha. in the neighborhood of 11.5 and .alpha.-.alpha.'.apprxeq.4.8. Such secondary correlation peaks adversely affect the condition number of the metric g(a,a'), and thereby diminish the instrument accuracy.
This problem may be alleviated to a considerable extent by using light with a plurality of substantially monochromatic components at different wavelengths. For example, the illuminating collimated light beam may be composed of spatially separated but parallel parts of nearly monochromatic light in the blue (400.div.500 .mu.m), green (500.div.600 .mu.m), and red (600.div.700 .mu.m) as shown in FIG. 9. Of course, the spatial filter must be modified to act properly on the incident multi-wavelength light. This is done by making the spatial filter in the form of a color transparency, with appropriate transmittance functions in the blue, green, and red. Distinguishing different colors by the index c, the sequence of Eqs. (8) to (13) become, for the multiple-wavelength case ##EQU20## similar modifications, amounting to replacing the scalar product by the "color" scalar product , apply to the remaining equations, (14) to (20). Eq. (10') shows that the color scalar product is simply the sum, over all colors, of the ordinary scalar product.multidot.in Hilbert space. If for the transmittance function for color c of the spatial filter j one chooses the function v.sub.cj, then the correlation v v.sub.j occuring in (13') is implemented by the spatial filter action. For the multiple-wavelength case one has, instead of Eqs. (21) to (26), ##EQU21## where .lambda..sub.c is the wavelength for the nearly monochromatic light labeled by the color index c, ##EQU22## The relief from strong secondary correlation peaks provided by the color sum in (26') is now evident: for a and a'.noteq.a such that there is a strong correlation in one color, there is usually weak correlation in the other colors; hence, in the color sum (26'), the secondary correlation peaks are diminished.
The implementation of the multiple-wavelength scheme may be accomplished as follows. Referring to FIG. 9, a light source 300 produces a collimated or nearby collimated beam 301 of substantially white light, which is made to pass through a spectral filter 302, which consists of three sections 302a, 302b, and 302c, which respectively pass light in a narrow spectral region in the blue, green, and red. The resulting tri-color collimated beam 303 with axis 303a illuminates the particle suspension. A lens or lens system 304 processes light scattered by the particles located in the intersection 303b of the beam 303 and the cone 305, the latter constituting the field of view of an optical configuration consisting of lens 304, and an image window 306, located in the focal plane 307 of lens 304. A polarizing element 308 is placed in the path of the scattered light, preferably but not necessarily between the lens 304 and the image window 306.
A set of spatial filters 309 is mounted on a disc 310 in plane 307. Arrangements are made such that, in time, different spatial filters are switched in the position of window 306.
An alternate embodiment of the switching concept, shown in FIG. 10, consists of a filmstrip 310a, the frames of which are the individual spatial filters. The film strip is moved past the window in step-wise motion-picture fashion. The filmstrip can be looped, without beginning or end, if preferred.
The spatial filters 309 of FIG. 9, and 309 of FIG. 10 are color-film transparencies with certain spatial transmittance functions in the blue, green, and red. Color photography uses the three primary colors blue, green, and red. The subtractive system employs three dyes, yellow, magenta, and cyan, in a layered structure (see, for instance, C. E. K. Mees and T. H. James, "The Theory of the Photographic Process", 3rd Edition, the Macmillan Company, New York, 1966). This allows the use of a color slide as a spatial filter with desired spatial transmittance distributions (over the slide) for three selected wavelengths in the blue, green, and red. The choice of these three wavelengths and the choice of film should be based on the spectral sensitivity curves and spectral dye density curves for the three components of color films; the choice must be such as to minimize interimage effects. To a certain extent, residual interimage effects may be compensated for by an adjustment of the exposure distributions used in the spatial filter production process, and, if desired, by adjusting the definition of the color scalar product , in (10'), (11') (12') and (13') such as to account for a color metric with off-diagonal terms representing residual interimage effects, and differences in diagonal terms representing residual differential sensitivity effects between different colors, all in a manner which will be evident to those skilled in the art.
There is the option of chopping the beam 301 or 303 by a chopper 313, and using synchronous detection in a manner which will be evident to those skilled in the art.
There is the further option of having either disc or filmstrip move continuously, and to flash the light source 300 synchronously with the filter position. A gated amplifier or integrator can then be used in the signal processing.
Behind the image window 306 and the spatial filter 309 there is a photodetector 311, which is usually a photomultiplier tube. With the ith spatial filter in place, the signal from the photodetector 311, usually after amplification and integration, (possibly gated), is measured and serves as input s.sub.i for a computer 312, which may be a computer, a microprocessor, or an analog device, such as a CCD, or CTD. There are N+1 different spatial filters on the disc 310, and hence, there are N+1 signals s.sub.i. The computer 312 is programmed such as to execute the algorithm (13'), where the matrix C.sub.ij.sup.-1 is the inverse of the matrix C.sub.ij given by (11'). Background subtraction may be achieved by color-generalizing Eq. (16), and biasing the filter transmittances to non-negative values may be achieved by color-generalizing Eqs. (17), (18), (19), and (20), in a manner which will be evident to those skilled in the art. The considerations concerning polarization, as discussed above for the monchromatic instrument, apply without change to the multiple-wavelength instrument. The same comment applies to the considerations pertaining to the illuminating light intensities for the different frames or spatial filters.
Although the multi-wavelength scheme was discussed above in terms of the three colors; blue, green, and red, there are practical considerations which may make a two-color scheme more suitable; the two colors are then to be chosen from the blue, green, and red. The practical considerations mentioned above include: the blue content of the light source, cost, and interimage effects of the color film.
The illuminating beam shown in FIGS. 9 and 10 consist of adjacent monochromatic beams, as a matter of convenience. For the working of the instrument, however, the different colors in the beam need not be spatially separated; in fact, there is some merit in spatial mixing of the different colors, or in the production of a multiple-wavelength beam by means of a layered set of spectral filters which absorb the unwanted portions of the spectrum of the light emitted by the source. Yet another manner of producing the multiple-wavelength illuminating light beam is to utilize a light source whose spectrum contains strong lines or line groups, and to employ spectral filters to subtract unwanted spectral lines or continuous spectral ranges.
The preferred embodiment of the invention and its best mode for the use in clouds and fog is shown in FIG. 10. In this case, near backscattering is used, making it possible to have a light source 300 and detector unit close together while sampling a substantial volume of cloud or fog. Also, a two-color scheme is used, with the colors green and red. The element numbers are the same as in FIG. 9, with the exception of the embodiment of the set of spatial filters, which now is in the form of a color filmstrip 310a looped and therefore without end.
All the methods for construction of the spatial filters which are discussed above for the single wavelength case may be used for the multiple-wavelength instrument as well, with the provision that the color slides which are to serve as spatial filters are produced by multiple exposure to the separate, nearly monochromatic, light components used in the multiple-wavelength scheme, taken in the blue, green, or red, as the case may be. The preferred method for the construction of the spatial filters consists again of controlling a camera orientation by means of two computer-driven angular positioners, and by illuminating the camera lens with a fixed collimated light beam, which either passes through a computer-controlled shutter, or else, has an intensity modulated by the computer. However, for the multiple-wavelength scheme we use multiple film exposure in which the wavelength of the illuminating collimated light beam is sequentially switched through the set of wavelengths employed.
using the resulting data sequence as coefficients in a linear combination of basis functions to yield the particle size distribution.
2. A method according to claim 1 in which the filter set is carried by a rotating disc.
3. A method according to claim 2 in which said disc moves continuously, and the light source is flashed when a member of the set of spatial filters is aligned with said image window.
4. A method according to claim 1 in which the filter set comprises a filmstrip.
5. A method according to claim 4 in which the filmstrip moves continuously, and the light source is flashed when a member of the set of spatial filters is aligned with said image window.
6. A method according to claim 1 in which the filters are color transparencies which have, for each said light component of said spectral set, a non-uniform transmittance which at any point P of the filter is a function of the angle.theta. which rays that have P as an image make with the axis of the illuminating beam.
7. A method according to claim 6 in which the filter transmittance, for each said light component of said spectral set, is computer generated from Mie intensity scattering calculations.
8. A method according to claim 1 in which one of the filters of the set has a uniform transmittance for each said light component of said spectral set.
9. A method according to claim 8 in which said uniform transmittance filter is used for subtraction of background light.
10. A method according to claim 1 in which the collected scattering angle range is near backward scattering.
11. A method according to claim 1 in which ((the computer comprises a microprocessor)) said linear transformation and the said linear combination are performed by a microprocessor.
12. A method according to claim 1 in which ((the computer comprises an analog device)) said linear transformation and the said linear combination are performed by an analog device.
13. A method according to claim 1 in which a polarizing element is placed in the path of the said scattered light.
14. A method according to claim 13 in which the polarizing element is placed ahead of the spatial filters.
15. A method according to claim 1 in which a light chopper is placed in the illuminating beam.
16. A method according to claim 15 in which synchronous detection is used for the photodetector signal.
17. A method according to claim 1 in which a filter with non-uniform transmittance is provided in said set to be used for subtraction of background light.
18. A method according to claim 1 in which said beam is polarized.
19. A method according to claim 18 in which the filter set is carried by a rotating disc.
20. A method according to claim 19 in which said disc moves continuously, and the light source is flashed when a member of the set of spatial filters is aligned with said image window.
21. A method according to claim 18 in which the filter set comprises a filmstrip.
22. A method according to claim 21 in which the filmstrip moves continuously, and the light source is flashed when a member of the set of spatial filters is aligned with said image window.
23. A method according to claim 18 in which the filters are color transparencies which have, for each said light component of said spectral set, a non-uniform transmittance which at any point P of the filter is a function of the angle.theta. which rays that pass through the point P make with the axis of the illuminating beam.
24. A method according to claim 23 in which the filter transmittance, for each said light component of said spectral set, is computer generated from Mie intensity scattering calculations.
25. A method according to claim 18 in which one of the filters of the set has a uniform transmittance, for each said light component of said spectral set.
26. A method according to claim 18 in which the scattering angle range is near backward scattering.
27. A method according to claim 18 in which a polarizing element is placed in the path of the said scattered light.
28. A method according to claim 27 in which the polarizing element is placed ahead of the spatial filters.
a photodetector to produce a sequence of signals each of which is substantially proportional to light transmitted by a respective filter.
30. Apparatus according to claim 29 in which polarizing means is placed in the path of the beam provided by said source.
31. Apparatus according to claim 29 in which polarizing means is placed on the axis of said lens, ahead of said filters.
32. Apparatus according to claim 29 in which the filters are mounted on a rotatable disc.
33. Apparatus according to claim 32 in which means is provided for acting upon said sequence of signals from the photodetector by a linear transformation and using the results as coefficients in a linear combination of basis functions to yield the particle size distribution.
34. Apparatus according to claim 29 in which the filters are comprised of a film strip.
35. Apparatus according to claim 34 in which means is provided for acting upon said sequence of signals from the photodetector by a linear transformation and using the results as coefficients in a linear combination of basis functions to yield the particle size distribution.
36. Apparatus according to claim 29 in which chopper means, synchronized with the presentation of the spatial filter set, intermittently impedes the passage of light to the suspension.
37. Apparatus according to claim 36 in which means is provided for acting upon said sequence of signals from the photodetector by a linear transformation and using the results as coefficients in a linear combination of basis functions to yield the particle size distribution.
38. Apparatus according to claim 29 in which the filters comprise color transparencies which, for every said substantially monochromatic light component of said beam, has a non-uniform transmittance, which at any point P of the filter is a function of the angle.theta. which rays that pass through the point P make with the axis of the illuminating beam.
means for acting upon said sequence of signals from the photodetector by a linear transformation and using the results as coefficients in a linear combination of basis functions to yield the particle size distribution.
40. Apparatus according to claim 39 in which means is provided for flashing said light source intermittently.
41. Apparatus according to claim 39 in which one of the filters of said set has a uniform transmittance, and in which the said last means is so arranged as to subtract the scaled photodetector signal for the uniform filter from the scaled signals for respective non-uniform filters, followed by using the resulting data as coefficients in a linear combination of basis functions.
42. Apparatus according to claim 39 in which polarizing means is placed in the path of the beam provided by said source.
43. Apparatus according to claim 39 in which polarizing means is placed on the axis of said lens, ahead of said filters.
45. A method according to claim 44 in which a filter with non-uniform transmittance is provided in said set respective to background light.
46. A method according to claim 44 in which said beam is polarized.
Malvern Instrument Ltd., Division of Precision Devices and Systems, Malvern Worcestershire, England, "Particle and Droplet Size Distribution Analyzer Type St 1800".


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STAFFORD — How frustrating have runner-up finishes been in 2016 for Joey Ferrigno at Stafford Motor Speedway?
So bad that one week he even pulled into victory lane thinking he won and then was chased back by officials into second place after a review of the finish.
Friday at Stafford Motor Speedway, there no questions who belonged in victory lane.
Ferrigno drove away from the field on a green-white-checkered restart to win the 20-lap SK Light Modified feature Friday at Stafford.
"It's been a long time coming," Ferrigno said. "… We even rolled the car into victory lane one night and ended up being second after the photo finish. I've got to thank all my guys for this."
Al Wisialko of Westwood, Mass. was second and Joe Graf of Mahwah, N.J., third.
It was the first victory of the season for Ferrigno, who had finished second three times in seven starts before Friday.
"A couple of them, I was right there," Ferrigno said. "That's racing. Look at Ted Christopher, he went all year [in 2015] without winning and he's still the king. A lot of it's skill and a lot of it's doing your homework in the shop and the rest of it comes down to luck. With the victories, it just hasn't been on my side this year. We've been staying out of wrecks, keeping the car in one piece, we've been definitely putting the time in the shop and tonight the cards fell in our favor.
"It just shows the hard work of my crew and all my guys at the shop. They didn't leave a nut or bolt unturned on my car. Checked everything out and it just shows their determination to give me the best car I can have every week."
Ferrigno went by David Arute for the lead on lap six and never trailed again. The caution flew with two laps remaining to set up the green-white-checkered, but Ferrigno staved off Wisialko's challenge.
"I've got to thank Jeff Pearl for that," Ferrigno said. "He put a ton of work into this [transmission] over the winter. This thing is unbeatable on restarts."
Said Wisialko: "He got a little tight down in [turns] one and two there and I saw the opening and just had to take it with two laps to go. And he did all he could to take the win, so congrats to Joey Ferrigno. But [the car] was just on rails, definitely the fastest car out here tonight."
Storms washed out qualifying at Kentucky Speedway on Friday at Sparta, Ky., putting Kevin Harvick on the pole for Saturday night's Sprint Cup Series race based on owner points. Brad Keselowski will be alongside Harvick in the No. 2 Ford.
Severe weather moved over the track near midday and shortened practice to around 30 minutes. A brief sprinkle followed but cars returned to the track for practice with another session scheduled for evening.


HOME → Seasonal → easter → Decorating for Easter gift, stand - a hare for the eggs.
Decorating for Easter gift, stand – a hare for the eggs.
Easter days are coming, so we are publishing an article that will help you prepare for this day: to do with their hands and decorate Easter gifts (painted or decorated) eggs. In this article, you will see a simple and intuitive way to make a decoration for your Easter gift set or a decorative holder for the egg.
pompoms and eyes for Bunny (optional).
Fold the towel, as shown in the photo below.
Catch the rubber band, and the top tape preparation, are obtained and the ears of a rabbit body.
Stand an egg or a decorative element Easter gift is ready!
Easter Decoration ideas: crafts with eggs!


text:
Rajasthan in Good Governance Index, 2021
Published on: 29-Dec-21
Rajasthan Polity and Governance Add to Study Deck 0
Why in News?
=> On the occasion of Good Governance Day on December 25, 2021, the Good Governance Index was released by the Union Home and Cooperation Minister Amit Shah, in which Rajasthan has got the second rank in Group 'B'.
=> In the GGI-2021, the ranking has been given by dividing the states and union territories into four categories - Group A, Group B, North Eastern and Hill States, Union Territories. 58 indicators from 10 sectors have been considered for preparing GGI-2021.
=> Rajasthan has secured second rank in Group 'B' with a score of 4.884 in the overall ranking of Good Governance Index, Madhya Pradesh has secured first rank in this group and Gujarat has secured first rank in Group 'A'.
=> Rajasthan has increased its score by 1.7 percent as compared to the previous index (2019). Last time its score was 4.80, which has now increased to 4.88.
=> The Good Governance Index is based on 10 sectors, in which Rajasthan's ranking and score are as follows-
By: ASRAF UDDIN AHMED
subhash_ias@yahoo.co.in


Collective intelligence is a shared or group intelligence that emerges from the collaboration and competition of many individuals. Collective intelligence appears in a wide variety of forms of consensus decision making in bacteria, animals, humans, and computer networks. The study of collective intelligence may properly be considered a subfield of sociology, of business, of computer science, of mass communications and of mass behavior—a field that studies collective behavior from the level of quarks to the level of bacterial, plant, animal, and human societies.
The above definition has emerged from the writings of Peter Russell (1983), Tom Atlee (1993), Pierre Lévy (1994), Howard Bloom (1995), Francis Heylighen (1995), Douglas Engelbart, Cliff Joslyn, Ron Dembo, Gottfried Mayer-Kress (2003) and other theorists. Collective intelligence is referred to as Symbiotic intelligence by Norman L. Johnson.
Collective intelligence (CI) can also be defined as a form of networking enabled by the rise of communications technology, namely the Internet. Web 2.0 has enabled interactivity and thus, users are able to generate their own content. Collective Intelligence draws on this to enhance the social pool of existing knowledge. Henry Jenkins, a key theorist of new media and media convergence draws on the theory that collective intelligence can be attributed to media convergence and participatory culture. Collective intelligence is not merely a quantitative contribution of information from all cultures, it is also qualitative.
One CI pioneer, George Pór, defined the collective intelligence phenomenon as "the capacity of human communities to evolve towards higher order complexity and harmony, through such innovation mechanisms as differentiation and integration, competition and collaboration." Tom Atlee and George Pór state that "collective intelligence also involves achieving a single focus of attention and standard of metrics which provide an appropriate threshold of action". Their approach is rooted in Scientific Community Metaphor.
Levy and de Kerckhove consider CI from a mass communications perspective, focusing on the ability of networked ICT's to enhance the community knowledge pool. They suggest that these communications tools enable humans to interact and to share and collaborate with both ease and speed (Flew 2008). With the development of the Internet and its widespread use, the opportunity to contribute to community-based knowledge forums, such as Wikipedia, is greater than ever before. These computer networks give participating users the opportunity to store and to retrieve knowledge through the collective access to these databases and allow them to "harness the hive" (Raymond 1998; Herz 2005 in Flew 2008). Researchers at the MIT Center for Collective Intelligence research and explore collective intelligence of groups of people and computers.
Howard Bloom traces the evolution of collective intelligence from the days of our bacterial ancestors 3.5 billion years ago to the present and demonstrates how a multi-species intelligence has worked since the beginning of life.
Tom Atlee and George Pór, on the other hand, feel that while group theory and artificial intelligence have something to offer, the field of collective intelligence should be seen by some as primarily a human enterprise in which mind-sets, a willingness to share, and an openness to the value of distributed intelligence for the common good are paramount. Individuals who respect collective intelligence, say Atlee and Pór, are confident of their own abilities and recognize that the whole is indeed greater than the sum of any individual parts.
From Pór and Atlee's point of view, maximizing collective intelligence relies on the ability of an organization to accept and develop "The Golden Suggestion", which is any potentially useful input from any member. Groupthink often hampers collective intelligence by limiting input to a select few individuals or filtering potential Golden Suggestions without fully developing them to implementation.
Knowledge focusing through various voting methods has the potential for many unique perspectives to converge through the assumption that uninformed voting is to some degree random and can be filtered from the decision process leaving only a residue of informed consensus. Critics point out that often bad ideas, misunderstandings, and misconceptions are widely held, and that structuring of the decision process must favor experts who are presumably less prone to random or misinformed voting in a given context.
While these are the views of experts like Atlee and Pór, other founding fathers of collective intelligence see the field differently. Francis Heylighen, Valerie Turchin, and Gottfried Mayer-Kress view collective intelligence through the lens of computer science and cybernetics. Howard Bloom stresses the biological adaptations that have turned most of this earth's living beings into components of what he calls "a learning machine". And Peter Russell, Elisabet Sahtouris, and Barbara Marx Hubbard (originator of the term "conscious evolution") are inspired by the visions of a noosphere — a transcendent, rapidly evolving collective intelligence — an informational cortex of the planet.
Perhaps we may draw parallels between this informational cortex and the Internet. Defined by the Internet Society in 1995 as '... the global information system that... provides, uses or makes accessible, either publicly or privately, high level services layered on... communications and related infrastructure...' (Leiner et al. 2003) we can see how the Internet lends itself to becoming this 'cortex'. Developing as far back as the late 1950's, it wasn't until 1991 that WWW (World Wide Web) was released. In 2005, there were as many as 1,018, 057, 389 Internet users worldwide (CIA 2008). So many users accessing the Internet can only mean one thing — a meeting of minds and collaboration of knowledge. The Internet is an information and communication tool, whether it be checking on the stock market or a celebrity gossip site, humans are primarily interested in the sharing of information, and the Internet serves this purpose.
According to Don Tapscott and Anthony D. Williams, collective intelligence is mass collaboration. In order for this concept to happen, four principles need to exist. These are openness, peering, sharing and acting globally.
During the early ages of the communications technology, people and companies are reluctant to share ideas, intellectual property and encourage self-motivation. The reason for this is these resources provide the edge over competitors. Now people and companies tend to loosen hold over these resources because they reap more benefits in doing so. By allowing others to share ideas and bid for franchising, their products are able to gain significant improvement and scrutiny through collaboration.
This principle has been the subject of debate for many, with the question being "Should there be no laws against distribution of intellectual property?" Research has shown that more and more companies have started to share some, while maintaining some degree of control over others, like potential and critical patent rights. This is because companies have realized that by limiting all their intellectual property, they are shutting out all possible opportunities. Sharing some has allowed them to expand their market and bring products out more quickly.
The emergence of communication technology has prompted the rise of global companies, or e-Commerce. E-Commerce has allowed individuals to set up businesses at almost no or low overhead costs. As the influence of the Internet is widespread, a globally integrated company would have no geographical boundaries. They would also have global connections, allowing them to gain access to new markets, ideas and technology. Therefore it is important for firms to stay globally competitive and updated or they will face a declining rate of clientele.
An early precursor of the concept of collective intelligence was entomologist William Morton Wheeler's observation that seemingly independent individuals can cooperate so closely as to become indistinguishable from a single organism. In 1911 Wheeler saw this collaborative process at work in ants, who acted like the cells of a single beast with a collective mind. He called the larger creature that the colony seemed to form a "superorganism".
In 1912, Émile Durkheim identified society as the sole source of human logical thought. He argues in The Elementary Forms of Religious Life that society constitutes a higher intelligence because it transcends the individual over space and time.
Collective intelligence, which has antecedents in Vladimir Vernadsky's concept of "noosphere" as well as H.G. Wells's concept of "world brain," has more recently been examined in depth by Pierre Lévy in a book by the same name, by Howard Bloom in Global Brain (see also the term global brain), by Howard Rheingold in Smart Mobs, and by Robert David Steele Vivas in The New Craft of Intelligence. The latter introduces the concept of all citizens as "intelligence minutemen," drawing only on legal and ethical sources of information, as able to create a "public intelligence" that keeps public officials and corporate managers honest, turning the concept of "national intelligence" on its head (previously concerned about spies and secrecy).
In 1986, Howard Bloom combined the concepts of apoptosis, parallel distributed processing, group selection, and the superorganism to produce a theory of how a collective intelligence works. Later, he went further and showed how collective intelligences like those of competing bacterial colonies and of competing human societies can be explained in terms of computer-generated "complex adaptive systems" and the "genetic algorithms", concepts pioneered by John Holland.
The developer of the World Wide Web, Tim Berners-Lee, has made it with the goal to promote sharing and publishing of information globally. Later, his employer opened up the WWW technology for free use. In the early '90s, the Internet's potential was still untapped, until the mid '90s where 'critical mass', as termed by the head of the Advanced Research Project Agency (ARPA), Dr. J.C.R. Licklider demanded for more accessibility and utility of the Internet. Hence, it can be said that the driving force behind collective intelligence is the digitization of information and communication. This is because existence of hyperlink has made it easier to search and create websites and pages. Knowledge can be built in just a matter of minutes.
David Skrbina cites the concept of a 'group mind' as being derived from Plato's concept of panpsychism (that mind or consciousness is omnipresent and exists in all matter). He follows the development of the concept of a 'group mind' as articulated by Hobbes in relation to his Leviathan which functioned as a coherent entity and Fechner's arguments for a collective consciousness of mankind. He cites Durkheim as the most notable advocate of a 'collective consciousness" and Teilhard as the thinker who has developed the philosophical implications of the group mind more than any other.
Collective intelligence is an amplification of the precepts of the Founding Fathers, as represented by Thomas Jefferson in his statement, "A Nation's best defense is an educated citizenry." During the industrial era, schools and corporations took a turn toward separating elites from the people they expected to follow them. Both government and private sector organizations glorified bureaucracy and, with bureaucracy, secrecy and compartmentalized knowledge. In the past twenty years, a body of knowledge has emerged which demonstrates that secrecy is actually pathological, and enables selfish decisions against the public interest. Collective intelligence restores the power of the people over their society, and neutralizes the power of vested interests that manipulate information to concentrate wealth.
The best-known collective intelligence projects are political parties, which mobilize large numbers of people to form policy, select candidates and to finance and run election campaigns. Military units, trade unions, and corporations are focused on more narrow concerns but would satisfy some definitions of a genuine "C.I."—the most rigorous definition would require a capacity to respond to very arbitrary conditions without orders or guidance from "law" or "customers" that tightly constrain actions. Another example is in which online advertising companies like BootB and DesignBay are using collective intelligence in order to bypass traditional marketing and creative agencies.
Improvisational actors also experience a type of collective intelligence, which they term 'Group Mind'.
Another form of collective intelligence is the Learner generated context in which a group of users collaboratively marshall available resources to create an ecology that meets their needs often (but not only) in relation to the co-configuration, co-creation and co-design of a particular learning space that allows learners to create their own context. In this sense, the learner generated contexts represents an ad hoc community which facilitates the coordination of collective action in a network of trust.
Ant societies exhibit more intelligence than any other animal except for humans, if we measure intelligence in terms of technology. Ant societies are able to do agriculture, in fact several different forms of agriculture. Some ant societies keep livestock of various forms, for example, some ants keep and care for aphids for "milking". Leaf cutters care for fungi and carry leaves to feed the fungi.
However, a majority will agree that the medium that displays collective intelligence in full is Wikipedia. It is an encyclopedia that can be altered by virtually anyone at any time. This concept is termed 'wikinomics' by Don Tapscott and Anthony D. Williams in their book similarly named, they quote Sunday Times, "'wikinomics' is the new force that is bringing people together on the net to create a giant brain". Through this application, the lines between a consumer and producer have been blurred, inventing the term 'prod-user' or 'prosumer'.
More examples on collective intelligence can be seen in games. Games such as The Sims, Halo or Second Life are designed to be more non-linear and depend on collective intelligence for expansion. This way of sharing is gradually evolving and influencing the mindset of the current and future generations. For them, collective intelligence has become a norm.
One measure sometimes applied, especially by more artificial intelligence focused theorists, is a "collective intelligence quotient" (or "cooperation quotient")—which presumably can be measured like the "individual" intelligence quotient (IQ)—thus making it possible to determine the marginal extra intelligence added by each new individual participating in the collective, thus using metrics to avoid the hazards of group think and stupidity.
In 2001, Tadeusz (Ted) Szuba from the AGH University in Poland proposed a formal model for the phenomenon of Collective Intelligence. It is assumed to be an unconscious, random, parallel, and distributed computational process, run in mathematical logic by the social structure.
In this model, beings and information are modeled as abstract information molecules carrying expressions of mathematical logic. They are quasi-randomly displacing due to their interaction with their environments with their intended displacements. Their interaction in abstract computational space creates multithread inference process which we perceive as Collective Intelligence. Thus, a non-Turing model of computation is used. This theory allows simple formal definition of Collective Intelligence as the property of social structure and seems to be working well for a wide spectrum of beings, from bacterial colonies up to human social structures. Collective Intelligence considered as a specific computational process is providing a straightforward explanation of several social phenomena. For this model of Collective Intelligence, the formal definition of IQS (IQ Social) was proposed and was defined as "the probability function over the time and domain of N-element inferences which are reflecting inference activity of the social structure." While IQS seems to be computationally hard, modeling of social structure in terms of a computational process as described above gives a chance for approximation. Prospective applications are optimization of companies through the maximization of their IQS, and the analysis of drug resistance against Collective Intelligence of bacterial colonies.
Because of the Internet's ability to rapidly convey large amounts of information throughout the world, the use of collective intelligence to predict stock prices and stock price direction has become increasingly viable in long or even short term applications. Utilizing these attributes, websites have been created to aggregate stock market information that is as current as possible. Consequently, professional or amateur stock analysts can publish their viewpoints and participate in creating an aggregate opinion on specific stocks or the stock market in general. Although it has been commonly expected, at least within the investment community, for investment banks and brokerages to publish their ratings and reports on stocks, the Internet has enabled the amateur or less notorious investors to concurrently submit their financial opinions. As a result, the opinion of any investor can be weighted on par with any other. Thus, a pivotal premise of the effective application of collective intelligence can be more thoroughly applied: the masses, including a broad spectrum of stock market expertise, could be utilized to, in theory, more accurately predict the behavior of financial markets.
New media is often associated with the promotion and enhancement of collective intelligence. The ability of new media to easily store and retrieve information, predominantly through databases and the Internet, allows it for it to be shared without difficulty. Thus, through interaction with new media, knowledge easily passes between sources, resulting in a form of collective intelligence. The use of interactive new media, particularly the Internet, promotes online interaction and this distribution of knowledge between users.
In this context, collective intelligence is often confused with shared knowledge. The former is knowledge that is generally available to all members of a community, whilst the latter is information known by all members of a community.
Collective intelligence as represented by Web 2.0 has less user engagement than collaborative intelligence.
In Terry Flew's discussion of 'interactivity' in the online games environment, the ongoing interactive dialogue between users and game developers, he refers to Pierre Levy's concept of Collective Intelligence (Levy 1998). He argues this concept is actively at play in videogames as clans or guilds in MMORG are constantly working together in order to achieve the goals/aims of the games. Henry Jenkins proposes that the participatory cultures emerging between games producers, media companies, and the end-users mark out a fundamental shift in the nature of media production and consumption. Jenkins argues that this new participatory culture arises at the intersection of three broad new media trends. Firstly, the development of new media tools/technologies enabling the creation of content. Secondly, the rise of subcultures promoting such creations, and lastly, the growth of value adding media conglomerates, which foster image, idea and narrative flow. Cultural theorist and online community developer, John Banks considered the contribution of online fan communities in the creation of the Trainz product. He argued that its commercial success was fundamentally dependant upon "the formation and growth of an active and vibrant online fan community that would both actively promote the product and create content- extensions and additions to the game software". The increase in user created content and interactivity gives rise to issues of control over the game itself and ownership of the player-created content. This gives rise to fundamental legal issues, highlighted by Lessig and Bray and Konsynski, such as Intellectual Property and property ownership rights.
Gosney extends this issue of Collective Intelligence in videogames one step further in his discussion of Alternate Reality Gaming. This genre, he describes as an "across-media game that deliberately blurs the line between the in-game and out-of-game experiences" as events that happen outside the game reality "reach out" into the player's lives in order to bring them together. Solving the game requires "the collective and collaborative efforts of multiple players"; thus the issue of collective and collaborative team play is essential to ARG. Gosney argues that the Alternate Reality genre of gaming dictates an unprecedented level of collaboration and "collective intelligence" in order to solve the mystery of the game.
Tom Atlee reflects that although humans have an innate ability to gather and analyze data, they are affected by culture, education and social institutions. A person, when analysed singularly tend to make decisions motivated by self-preservation. In addition, humans lack a way to make choices that has a balance between innovations and reality. Therefore, without collective intelligence, humans may just drive themselves into extinction based on their selfish needs.
Phillip Brown and Hugh Lauder quotes Bowles and Gintis (1976) that in order to truly define collective intelligence, it is crucial to separate 'intelligence' from IQism. They go on to argue that intelligence is an achievement and can only be developed if allowed to. For example, earlier on, groups from the lower levels of society are severely restricted from aggregating and pooling their intelligence. This is because the elites fear that the collective intelligence would convince the people to rebel. If there is no such capacity and relations, there would be no infrastructure on which collective intelligence is built. This reflects how powerful collective intelligence can be if left to develop.
At the rate technology is changing, no firm can fully keep up in the innovations needed to compete. Instead, smart firms are drawing on the power of mass collaboration to involve participation of the people they could not employ.
Firms can create a new market for complementary goods by engaging in open source community. For example, the growing popularity of Wikipedia provided Jimmy Wales with an idea to come up with Wikipedia-branded line of books.
Mass collaboration can help to reduce costs dramatically. Firms can release a specific software or product to be evaluated or debugged by online communities. The results will be more personal, robust and error-free products created in a short amount of time and costs.
Growth of the Internet and mobile telecom has also highlighted "swarming" or "rendezvous" technologies that enable meetings or even dates on demand. The full impact of such technology on collective intelligence and political effort has yet to be felt, but the anti-globalization movement relies heavily on e-mail, cell phones, pagers, SMS, and other means of organizing before, during, and after events. One theorist involved in both political and theoretical activity, Tom Atlee, quantifies on a disciplined basis the connections between these events and the political imperatives that drive them. The Indymedia organization does this in a more journalistic way, and there is some coverage of such current events even here at Wikipedia.
It seems likely that such resources could combine in future into a form of collective intelligence accountable only to the current participants but with some strong moral or linguistic guidance from generations of contributors - or even take on a more obviously democratic form, to advance some shared goals.
^ Émile Durkheim, The Elementary Forms of Religious Life, 1912.
^ Flew, T. 2008. New Media: An Introduction. 3rd ed. Melbourne: Oxford University Press.
^ Jenkins, H. 2006. Fans, Bloggers and Gamers: Exploring Participatory Culture. New York: New York University Press.
^ Flew, Terry and Humphreys, Sal (2005) "Games: Technology, Industry, Culture" in Terry Flew, New Media: An Introduction (2nd edn), Oxford University Press, South Melbourne 101-114.
^ Henry Jenkins (2002) in Flew, Terry and Humphreys, Sal (2005) Games: Technology, Industry, Culture in Terry Flew, New Media: An Introduction (2nd edn), Oxford University Press, South Melbourne 101-114.
^ L, Lessig,(2006)Code Version 2.0 (2nd ed.). New York: Basic Books.
^ Gosney, J.W, 2005, Beyond Reality: A Guide to Alternate Reality Gaming, Thomson Course Technology, Boston.
^ Brown, P. & Lauder, H. (2000). Collective Intelligence. In S. Baron, J. Field & T. Schuller (Eds.) Social Capital: Critical Perspectives (p.230) New York: Oxford University Press.
Flew, Terry. (2008). New Media: an introduction. Melbourne: Oxford University Press.
Sun, Ron, (2006). "Cognition and Multi-Agent Interaction". Cambridge University Press.
Cultivating Society's Civic Intelligence Doug Schuler. Journal of Society, Information and Communication, vol 4 No. 2.
This page was last modified on 27 March 2009, at 08:11.


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A money market or investment account requires a larger upfront sum to open than a savings account. Where a savings account can be opened for as little as R50, a money market account usually requires no less than R1000. For recurring investments, you'll have to invest a certain amount each month – usually R1 000 (but some accounts require only R200).
While the risk is less investing in a money market than it is investing in stocks, there is no guarantee that your returns or capital will remain or increase. While it is unlikely that your capital will decrease, it is possible. To avoid this, money market funds invest in a number of financial instruments to remain lucrative. The interest is linked to the interest rates, which means your returns will vary.
The money market still poses more of a risk than a savings account, as money market funds can be linked to other banks or institutions that can collapse, but it does provide more interest and slightly less liquidity than an average savings account.


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