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Changes to Navy-Marine Corps MARS
The US Department of Defense (DoD) is phasing out the US Navy-Marine Corps Military Auxiliary Radio System(MARS) program. Its operational mission will transition to the other MARS service branches by the end of September. The head of the US Navy-Marine Corps MARS program in Williamsburg, Virginia, made the announcement. The Navy-Marine Corps MARS program also supports the US Coast Guard as well as the Federal Emergency Management Agency, the US Department of Homeland Security, and local emergency management agencies. A US Department of Defense-sponsored program, MARS branches are separately managed by their respective military service branches. MARS volunteers are Amateur Radio operators who provide auxiliary or emergency communications to local, national, and international emergency and safety organizations, as an adjunct to normal communications.
"Naval Computer and Telecommunications Area Master Station Atlantic (NCTAMS LANT) intends to work with US Army MARS and US Air Force MARS in transitioning the Navy-Marine Corps MARS (NAVMARCORMARS) program by 30 Sep 2015," the announcement said. "The intent of the transition is to best align the program to support national mission requirements." Chris Jensen of NCTAMS LANT told ARRL that the Navy no longer has any service specific requirements for Navy-Marine Corps MARS and is working within DoD to transition the program into Army and Air Force MARS. "We will continue to publish updates as this transition progresses," he said.
The announcement encouraged current Navy-Marine Corps MARS members and clubs to submit applications to the US Army MARS or US Air Force MARS programs as soon as possible.
"The US Navy greatly appreciates the thousands of MARS volunteers, past and present, who have been integral to the success of MARS," the announcement concluded.
One individual who is very familiar with the MARS program said the change was not unexpected and came to a head as the US Strategic Command embraced Army MARS as the lead branch for contingency communication and Air Force MARS began partnering with the US Army program on the operations side.
"The Army and Air Force MARS branches have an obvious role in providing contingency communications for the 50 states," said the individual, who preferred not to be cited by name. "Members are everywhere 'on the ground,' and experience in Afghanistan and Iraq has proven the tactical usefulness of HF on land. There was no similar role for the landlocked membership of Navy-Marine Corps MARS."
He said the MARS program can use all the volunteers it can attract and hopes the Navy-Marine Corp MARS volunteers will join one of the other MARS branches.
Army MARS Program Manager Paul English, WD8DBY, echoed those sentiments. "Navy leadership will continue to stay engaged with the MARS services to support the DoD quarterly exercises and other training missions and requirements as they are identified," English said. "Both Army and Air Force leadership is committed to making the transition process from the Navy MARS program as smooth as possible. Navy volunteers in good standing will transition as full members; they will not have to start over."
"We understand this will be an emotional time for Navy members to decide if they want to continue supporting the MARS program," English added. "We value the service they contributed to the Navy and invite them to continue to serve in either the Army of Air Force MARS programs."
This entry was posted in Uncategorized on May 15, 2015 by admin.
MARS Exercise 15-1
Quarterly Exercise Concludes!
MARS operators from all three Services joined ranks to conduct a contingency HF communications exercise to train and demonstrate proficiency on sending encoded messages across the US during a simulated wide-spread communications outage. During this exercise MARS stations reached out to local amateur radio stations via radio only means in order to continue building the working relationship between these communities.
Thanks to everyone who trained in today's exercise! Your ability to react to a changing environment is a testament to your skill as HF operators. Keep up the good work!
This entry was posted in Uncategorized on March 10, 2015 by admin.
MARS Operators Train with UK Army Cadets
On 29 and 30 November, MARS members across the eastern and central US participated in the annual UK Army Cadet exercise "Christmas Cracker." This two day 31 hour exercise tested the UK Cadet operators' ability to establish international HF communications with MARS stations located in EUROPE and the United States on a variety of HF frequencies.
Coordination for this exercise was led by Captain David Holman, UK Army and Daniel Wolff, Army MARS EUROPE. On the results of the exercise, Captain Holman offered the following: "Our cadets are not only eager but very grateful for the ability to talk to overseas stations, something they had not done before. Many reported 'excitement' at being heard and actually speaking with a MARS Station."
Captain Holman further elaborated: "The scores indicate the large
number of exchanges (over 1,000) took place over the period of the
exercise and the hard work put in by the cadets and their adults. Special thanks must go to all of the MARS Stations who took part and were always there for us, often the time zone where they were based meant operating at extended times, and their help is very much appreciated."
HQ Army MARS appreciates the 44 Army and Navy MARS stations who participated in this international exercise. Events like this continue to build international esprit de corps…good job by all who participated!
This entry was posted in Uncategorized on December 23, 2014 by admin.
Radio amateurs in the Military Auxiliary Radio System (MARS) concluded an unprecedented 48-hour marathon exercise October 28th that linked the continental US, Hawaii, Japan, Europe, and Canada during a simulated breakdown of normal communication systems, including the Internet. For the first time in a nationwide test, W1AW staffers activated the Maxim Memorial Station Army MARS stationAAN1ARL at ARRL Headquarters to facilitate input from the Radio Amateur Civil Emergency Service (RACES) community.
"Well done by all," messaged Army MARS Chief Stephen Klinefelter, when the test was concluded. The exercise involved the transmission of hundreds of encrypted messages via HF radio. The traffic carried "situational awareness" information needed by a joint Department of Defense entity responsible for responding to a national crisis situation. Many operators, net control and relay station members in particular, put in long hours maintaining the seamless connection.
Joining Army MARS in providing backup communication for a US Department of Defense entity responsible for homeland security were members of the Navy-Marine Corps and Air Force MARS branches. Elements of the National Guard, FEMA, the Transportation Security Administration, and selected state authorities also participated.
During the final day of the exercise, MARS members also acted on a real-world request from DoD to be prepared to monitor International Amateur Radio Union (IARU) emergency frequencies as Typhoon Haiyan appeared poised to develop into a category 5 storm and strike the Philippines.
MARS members were given strict time limits for providing the requested information in order to receive credit for completing their message handling. These statistics will be used to evaluate how quickly and efficiently the multi-branched network might be able to handle information requests and responses under conditions mirroring an actual catastrophe. Poor propagation, particularly in the overnight hours, added a realistic touch.
A formal after-action report from Army MARS Program Officer Paul English, WD8DBY, and Operations Chief David McGinnis, K7UXO, in still in the works, but Klinefelter saluted the overall performance.
"You have just completed the most complex and longest MARS communications exercise in recent history," he said. "I want to thank each of you for participating and devoting long hours to make this exercise a success. The dedicated efforts to maintain effective nationwide contingency communications support demonstrated by all participants were exemplary."
This entry was posted in Uncategorized on November 2, 2014 by admin.
New AM 1 "This is Army MARS" Issued
The U.S. Army Military Auxiliary Radio System (ARMARS) is an elite group of dedicated citizen
volunteers who support a Global High Frequency Enterprise Radio Network (GHFERN). The GHFERN
provides contingency radio communications to the Department of Defense (DoD) in a variety of
circumstances, including complex catastrophes and cyber denied or impaired conditions. MARS is
the program that trains, organizes and tasks volunteer Amateur Radio operators to support the
GHFRERN.
Army MARS citizen-volunteers demonstrate the Army's values of Loyalty, Duty, Respect, Selfless-
Service, Honor, Integrity and Personal Courage, freely and generously giving their time and
resources as a reflection and measure of devotion to our nation. The world has changed
dramatically since the MARS structure was first developed and implemented but what has not
changed is the dedication of these citizens to serve.
Click here to read AM 1
Wyoming National Guard Utilizes Army MARS to Strengthen Communication Skills
September 30, 2013 at 9:08am
Nothing was usual about the National Guard/MARS meeting in Cheyenne on September 14. It all started far away with an Army MARS presentation to the National Guard Bureau by Army MARS Operations Officer David McGinnis and Program Manager Paul English in Little Rock. This created the spark that caused the C.O. of the 115th Fires Brigade Wyoming Army National Guard to ask the Army MARS Region 8 Director, Steve Carver, and through him CO/WY Army MARS members for some help. The long term intent of the N.G. units was mastery of ALE and effective use of digital signals on HF between brigade elements.
The MARS help came in the form of a six hour class on HF properties, NVIS, frequencies, antennas, and propagation by Army MARS Member Emit Hurdelbrink and Army MARS CO/WY State Director Steve Schroder. The practical exercises included deployment of the RF-1944 antenna and operation with a PRC-150c portable radio as initial contact was made with Army MARS Members in Pueblo, Colorado. Each individual practiced entering a scratchpad frequency and making a radio call. This small but successful event could well herald a long and fruitful future of National Guard/ MARS cooperation.
Meanwhile, the rain totals continued to accumulate in Colorado as the full scope of the flood damage was becoming frighteningly clear. The class ended with Steve Schroder racing south to Colorado, but continuing to talk to N.G. members on his mobile radio as the last three participants practiced making their radio calls.
Figure 2 Emit Hurdelbrink, right, with members of the 115th Fires Brigade Wyoming Army National Guard
Emit went to the Colorado State E.O.C. where he was greatly needed, and Steve was deployed for the next eight days at the ICP in Evans , Colorado. When the event was planned, no one could have guessed that an emergency training class and exercise would end in such an unusual and intense full blown emergency deployment. On the other hand, what could be more appropriate than putting emergency training into practice?
Robert D. Barclay, Region 8 PAO
MARS Operators Complete "Exemplary" Simulated Disaster Response Exercise
Radio amateurs in the Military Auxiliary Radio System (MARS) concluded an unprecedented 48-hour marathon exercise November 5 that linked the continental US, Hawaii, Japan, Europe, and Canada during a simulated breakdown of normal communication systems, including the Internet. For the first time in a nationwide test, W1AW staffers activated the Maxim Memorial Station Army MARS station AAN1ARL at ARRL Headquarters to facilitate input from the Radio Amateur Civil Emergency Service (RACES) community.
Joining Army MARS in providing backup communication for the US Department of Defense entity were members of the Navy-Marine Corps and Air Force MARS branches. Elements of the National Guard, FEMA, the Transportation Security Administration, and selected state authorities also participated.
Discussions between ARRL Headquarters staff, US Army MARS Region 1 leadership, and English preceded the exercise. Eastern Massachusetts was chosen for the first test of full-scale collaboration between ARES and MARS, and Tim Wortley, KQ1Y, the MARS state director for Southern New England, worked out the details with Eastern Massachusetts Section Emergency Coordinator Rob Macedo, KD1CY. Wortley said he received more than a half-dozen responses to inquiries he'd put into the system. Other tactical voice messages on amateur VHF repeaters were forwarded to MARS circuits. The ARES test was separate from the activation of the MARS station at W1AW.
This entry was posted in Uncategorized on November 18, 2013 by admin.


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Anna Janus-Sitarz – polska literaturoznawczyni, dr hab. nauk humanistycznych, profesor Katedry Polonistycznej Edukacji Nauczycielskiej Wydziału Polonistyki Uniwersytetu Jagiellońskiego.

Życiorys
W 1984 ukończyła studia filologii polskiej na Uniwersytecie Jagiellońskim, 21 czerwca 1993 obroniła pracę doktorską Groteska literacka w szkole, 2 grudnia 2009 habilitowała się na podstawie pracy zatytułowanej Przyjemność i odpowiedzialność w lekturze. O praktykach czytania literatury w szkole. Konstatacje. Oceny. Propozycje. 15 września 2017 nadano jej tytuł profesora w zakresie nauk humanistycznych.

Jest profesorem Katedry Polonistycznej Edukacji Nauczycielskiej Wydziału Polonistyki Uniwersytetu Jagiellońskiego, oraz specjalistą Komitetu Nauk o Literaturze na I Wydziale Nauk Humanistycznych i Społecznych Polskiej Akademii Nauk.

Przypisy

Polscy literaturoznawcy
Wykładowcy Uniwersytetu Jagiellońskiego
Absolwenci Uniwersytetu Jagiellońskiego
Urodzeni w XX wieku

redpajama_set_name: RedPajamaWikipedia


2020 Ford Expedition Diesel, Interior, For Sale – The logo-new age group from the Search SUV are available in 2018. With just about every company-new timeframe, the US carmaker will need to comprise of a thing to freshen the selection plus the interest. For that 2020 Ford Expedition which will easily be a product-new engine.


Help the cute Baboo animals and complete as many rainbow lines as possible! Your task in this addictive puzzle game is to drag the pieces onto the field to make vertical or horizontal lines. Only full lines will disappear from the field. Be careful and don't fill up the screen or the game is over! Try to get a double rainbow for extra points and earn as many points as you can!


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Abercrombie continues to flourish, with community support
Faculty Council meeting — Nov. 30, 2022
News from Harvard schools, offices, and affiliates
Ben Abercrombie and friends at the recent Bowl for Ben event. Photo by John Field
Kirsten Green kgreen@fas.harvard.edu https://gocrimson.com
Five years from his life-changing football injury, Ben Abercrombie continues his journey through Harvard, among a community which fiercely supports one of its most inspiring members.
Following his spinal cord injury, the Benson M. Abercrombie '21 Fund was established by the Harvard Varsity Club (HVC) to assist the Abercrombie family with the significant medical and continuing care expenses they incur. Three annual community events are held to support the fund, including El Jefe's Ben Abercrombie Day, Bowl for Ben, and 3.2 for Ben.
Though El Jefe's has a new home at 14 Brattle St. in Harvard Square, owner John Schall's annual Ben Abercrombie Day continues just the same when the fundraiser returns for a fifth year Dec. 6. All members of the Harvard community are invited to patronize the restaurant from 8 a.m. Dec. 6 to 4 a.m. Dec. 7, with all proceeds from the day (including gift card sales) donated to the Abercrombie Fund. To date, the El Jefe's fundraiser has raised over $125,000.
Last month, the HVC hosted its third annual 3.2 for Ben, a fundraising event that began under the gathering restrictions of the pandemic. This year, nearly 500 participants independently ran or walked 3.2 miles, at their own time and pace. The distance was chosen to honor the jersey number 32 that Abercrombie wore for the Crimson. The HVC also hosted its third annual Bowl for Ben fundraiser on Nov. 18 in Boston's Seaport District, on the eve of the 138th playing of The Game. More than 150 supporters turned out to celebrate the guest of honor.
In his first varsity football game in 2017, Abercrombie suffered a spinal cord injury which left him paralyzed below the neck. The economics concentrator has continued his education while battling years of medical treatment and extensive rehabilitation.

redpajama_set_name: RedPajamaCommonCrawl


On 18 January 2019, Shri Somnath Ghosh, Ambassador of India to Tajikistan met Tajik ITEC candidates at Conference Room at Chancery before their departure to India. In this batch, 23 ITEC candidates from Tajikistan are going to attend courses in IT, agriculture, industry, healthcare, business, management, networking, web designing etc in different prestigious institutes of India. Tajikistan sends large number of candidates under ITEC to India every year.


As a London pest control company we've been in the vermin treatment and control business for years and the technicians have seen quite a lot of things. They have also received some very interesting questions about one of the most common household pests – the mouse.
The Panther Mouse control experts have gathered all mice-related frequently asked questions in a list and will gladly give you some answers and a peace of mind.
What's The Difference Between A Rat And A Mouse?
Are Mice More Common In Winter?
How Do Mice Get In The House?
Where Do Mice Hide In A House?
How Many Mice Are Considered An Infestation?
What's the best bait for mouse traps?
If my house is clean, how can I have mice?
I haven't seen a mouse, do I have an infestation?
Why do I have mice when I have a cat?
Question 1: What's The Difference Between A Rat And A Mouse?
There's quite a substantial difference between the two species when it comes to appearance. The most common rat species invading UK homes is the Norwegian or brown rat. Adult individuals of both species are easy to differentiate. Rats are bigger in size and weigh somewhere between 350-400 grams and body length between 7 and 9 inches. Mice are tinier and lighter. They reach a body length of 3 to 4 inches and the same tail length. When it comes to weight they reach approximately 30 grams and vary from light brown to black and grey. Rats, on the other hand, are brown or grey.
Read more: Difference betwee mice and rats droppings.
Question 2: What Do Mice Eat?
Mice are omnivorous, which means that plants and meat are both included in their diet. Actually, they'd eat anything they can get their tiny paws on. When food is scarce they are known to become cannibals.
Question 3: Are Mice More Common In Winter?
When winter closes in, the weather becomes colder and outdoors living conditions become less favourable, mice often invade human dwellings. "My house is not old and I keep it clean. Why do I have mice in my house?" Why is that, really? There are a few reasons. They need food, and what a better way to get it than from human homes. Second, mice seek warmth so they can raise their babies undisturbed. And last, they are safe from predators like owls, as they have a secure hiding place.
Read more: Where do mice come from?
Question 4: How Do Mice Get In The House?
Mice have the physical ability to squeeze in tiny spaces under doors. Their bodies are flexible enough to almost "flatten" their rib cages, so they could pass through small holes. If they cannot do it, they are persistent enough to chew their way into your home. Yet, they'd prefer small crevices or cracks somewhere in your property which they could use as an entrance.
Question 5: Where Do Mice Hide In A House?
Their "sweet homes" are the places in your property which are often rarely or not-at-all used by people. These spots are basements, attics, storage boxes, wall interiors. Though they are close to people, they will live undisturbed by you.
Read more: What does house mice nest look like?
Question 6: How Many Mice Are Considered An Infestation?
If you don't check your property and pest-proof it often enough, it is almost certain you will have problems with a mouse infestation. At first, you might encounter one or two of these rodents, but they'd quickly grow in numbers. If there is enough food and space for them to live in peace, their tiny population would soon thrive. We'll give you a rough estimate: if a male and female remain in their nest and have mouse pups, their number would quickly grow to 8 babies, you'd have 10 mice in your property for starters.
Question 7: Do Mice Bite People?
Regardless of how terrified you are of mice, they're peaceful creatures and won't crawl into your bed while you're asleep to bite your nose off. If threatened, maybe when you grab them, they might bite you. Remember, they're just as terrified as you are. This would be the answer to "Are mice aggressive?" Otherwise, they wouldn't prefer living in unused rooms or spaces.
Question 8: What's the best bait for mouse traps?
Mice eat a lot of different things. They would gnaw through hard surfaces to get to your kitchen, after all. To capture a mouse in a trap you can try any of these 10 mice baits: chocolate, cheese with a strong smell, butter crackers, bird seeds, soft pet food, sweet soft candies, peanut butter, bacon, hot dog, maple syrup or honey.
Read more: Mice species in the UK.
Question 9: If my house is clean, how can I have mice?
Mice are not attracted only to dirty or disorderly houses. Such homes are just more likely to have a mice infestation due to the easy access to food and shelter for the mice and the small probability to see them. They seek shelter and food. They would enter your home, too, trying to find these things. If they can't find food, they might stay for the warmth it provides.
Question 10: I haven't seen a mouse, do I have an infestation?
Since mice prefer to move when it's dark so a predator won't notice them, it's natural that you don't see mice in your house. They also have no business in most of your house, they would usually only stick around the kitchen or your pantry, so you wouldn't see them in your bathroom or bedroom at night.
If you do, however, see them during daylight and especially outside of your kitchen, that can be a firm indicator that you have a heavy infestation and you need to seek professional help right away.
Question 11: Why do I have mice when I have a cat?
Not all cats are hunters. Especially cats that live in closed spaces. They are not used to chasing mice. Cats who live outdoors are more likely to have the natural urge to chase the mice. What is more, even if your cat is chasing the mice inside of the house it would be hard to catch it when the mice hide in the wall or some other small space.
Read more: Rodents pest control.


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Home / Resources / Blog & News
Backward Compatibility: QSFP-DD/QSFP28/QSFP+/SFP+
AuthorDerek
Backward compatibility is vital for optical modules. It is closely bound up with the network system upgrading and operation. Transceivers with backward compatibility will provide great flexibility for future data center deployment. This article will give a comprehensive backward compatibility guide to the most common transceiver types, including QSFP-DD backward compatibility, QSFP28 backward compatibility, QSFP backward compatibility, and SFP+ backward compatibility.
SFP+ Backward Compatibility
SFP+ Wiki
SFP+ (enhanced small form-factor pluggable) is designed for 10G networking applications. Before 10G SFP+, 10G optical transceivers have experienced the version of 300Pin, XENPAK, X2, and XFP. The most significant enhancement of SFP+ is realizing the 10 Gbit/s data rate in a very small form factor, which is the same as SFP. The SFP+ specification was first introduced in 2006. With the advantages of high density and low cost, SFP+ optical modules are always popular throughout the market for more than a decade. Today, 10G SFP+ can be seen everywhere in data centers. SFP+ transceivers are used in various applications, including Ethernet, Fibre Channel, and InfiniBand. The common SFP+ types include 10GBASE-SR, 10GBASE-LR, 10GBASE-T, 10G BiDi SFP+, and 10G SFP+ CWDM/DWDM.
Is SFP+ backward compatible with SFP?
Since SFP+ is exactly the same dimensions as SFP, it is backward compatible with SFP, but provides much higher data rates. SFP+ ports can work with 1G SFP modules, but it will work at 1Gbps instead of 10Gbps. The data rate configuration is not automatic generally, and you need to configure the port to 1G speed manually.
Is SFP+ compatible with XENPAK, X2?
How about the previous 10G module version of XENPAK, X2? Is SFP+ compatible with them? The answer is definitely no. If your SFP+ modules need to connect to the older equipment with XENPAK ports or X2 ports, a XENPAK to SFP+ converter adapter or X2 to SFP+ converter adapter will be needed.
QSFP+ Backward Compatibility
QSFP+ Wiki
QSFP+ (Quad Small Form-factor Pluggable Plus) supports data rates up to 40Gbps by four 10 Gbit/s channels. IEEE 802.3ba defines QSFP+. It is a litter bigger than SFP+, but it is still the highest density optical transceiver for 40 Gigabit Ethernet. The common QSFP+ optical transceiver types include 40G QSFP+ SR4, LR4, and ER4.
Is QSFP+ compatible with SFP+? How to convert a QSFP+ port to an SFP+ port?
Since the different physical dimensions, QSFP+ is not compatible with SFP+. Does this mean that the QSFP+ port can't connect with the SFP+ port? No, there are many solutions for converting a QSFP+ port to SFP+.
Solution 1: Using QSFP to SFP+ breakout cable
QSFP to 4 SFP+ copper direct attach breakout cable (DAC) and QSFP to four SFP+ active optical breakout cables can be used to connect to a 40G QSFP switch port on one end and to four 10G SFP+ ports on the other end. These two types of DAC and AOC breakout cables are both pre-terminated with a QSFP+ transceiver on one end and four SFP+ transceivers on the other end. Their main difference is that DAC uses copper cables while the AOC uses fiber cables. These breakout cables are perfect for those who need to connect short distances and they offer an extremely cost-effective and convenient way of doing so.
Solution 2: Using optical transceivers + MTP to LC breakout cable
This solution needs one QSFP optical transceiver and four SFP+ transceivers, then uses an MTP to LC 8 fiber breakout cable to connect them. The fiber breakout cables include MMF and SMF types, which to choose is determined by the two ends of optical transceivers. This solution can provide a much longer distance than the prior, but also costs more.
Solution 3: Using QSFP to SFP+ adapter
QSFP to SFP+ adapter converter is also a cost-effective way to convert QSFP+ to SFP+ port. It allows 10 Gigabit Ethernet connectivity on QSFP-only platforms. Plug and play, no configuration required. The QSA adapter interoperates with all major SFP+ optical transceiver modules, SFP+ direct attached copper cable (DAC), and active optical cables (AOC). With this clever adapter, you can flexibly use any SFP+ transceivers or cables to connect with a lower-speed port on the other end of your network.
QSFP28 Backward Compatibility
QSFP28 Wiki
QSFP28 is designed for 100G Ethernet and can support data rates up to 100 Gbps over four channels, each channel support 25Gbit/s. 100G QSFP28 transceivers are gradually replacing SFP and SFP+ as the top popular optical module type. The common 100G QSFP28 transceivers include 100G SR4, LR4, CWDM4, and PSM4. QSFP28 to QSFP28 cable is also popular in short-range 100G applications, including QSFP28 DAC and AOC. The typical 400G QSFP-DD transceivers include 400G QSFP-DD SR8, DR4, FR4, LR4, and LR8. And 200G QSFP-DD transceivers include 200G QSFP-DD SR8, PSM8, and LR8.
Is QSFP28 backward compatible with QSFP?
The answer is yes. QSFP28 has the same factor and size as QSFP. Both QSFP28 and QSFP have four lanes. QSFP28 supports 25Gbit/s per lane, while QSFP supports 10Gbit/s per lane. Similar physical form factor and working principle make QSFP28 backward compatible with QSFP.
QSFP-DD Backward Compatibility
QSFP-DD Wiki
QSFP-DD (Quad Small Form-factor Pluggable Double Density) is a new form factor, designed for the next-generation and high-density 200G and 400G Ethernet. It is compliant with the IEEE802.3bs and QSFP-DD MSA. As its name implies, compared to its predecessors of 4-lane QSFP28 and QSFP, QSFP-DD doubles the number of high-speed electrical interfaces, providing an eight-lane electrical interface.
Based on different lane data rates and modulation technology, QSFP-DD supports data rates up to 200Gbps or 400Gbps:
• 200Gbps: 8 lanes, supporting 25Gbps per lane, using NRZ modulation
• 400Gbps: 8 lanes, supporting 50Gbps per lane, using PAM4 modulation
Does QSFP-DD support backward compatibility? Which form factors does it support?
QSFP-DD is designed based on QSFP pluggable form factor. It has the same pinout as the QSFP connector. Therefore, QSFP-DD quadruples aggregate switch bandwidth while maintaining the port density. Also, QSFP-DD is backward compatible with the current QSFP form factor types, including 40G QSFP+, 100G QSFP28, and 200G QSFP56. This means that equipment designed with QSFP-DD connectors will be backward compatible, allowing them to support existing QSFP and QSFP28 modules and provide great flexibility for end users.
Form Factors
QSFP+, QSFP28
QSFP-DD
QSFP+, QSFP28, QSFP56


We went up to the latter; and giving the usual salutation, were on the point of vaulting over the bamboos, when they turned upon us angrily, and said we could not enter. We stated our earnest desire to see the queen; hinting that we were bearers of important dispatches. But it was to no purpose; and not a little vexed, we were obliged to return to Po-Po's without effecting anything.
scr888 free credit without deposit,But according to what view you take of it, it is either the gracious or the malicious gift of the great gods to man, that on the threshold of any wholly new and momentous devoted enterprise, the thousand ulterior intricacies and emperilings to which it must conduct; these, at the outset, are mostly withheld from sight; and so, through her ever-primeval wilderness Fortune's Knight rides on, alike ignorant of the palaces or the pitfalls in its heart. Surprising, and past all ordinary belief, are those strange oversights and inconsistencies, into which the enthusiastic meditation upon unique or extreme resolves will sometimes beget in young and over-ardent souls. That all-comprehending oneness, that calm representativeness, by which a steady philosophic mind reaches forth and draws to itself, in their collective entirety, the objects of its contemplations; that pertains not to the young enthusiast. By his eagerness, all objects are deceptively foreshortened; by his intensity each object is viewed as detached; so that essentially and relatively every thing is misseen by him. Already have we exposed that passing preposterousness in Pierre, which by reason of the above-named cause which we have endeavored to portray, induced him to cherish for a time four unitedly impossible designs. And now we behold this hapless youth all eager to involve himself in such an inextricable twist of Fate, that the three dextrous maids themselves could hardly disentangle him, if once he tie the complicating knots about him and Isabel.Yours are strange fancies, Marianna.I pretend not to divine your meaning there,Concerning the curious disposition to fraternise and be sociable, which this Shakings mentioned as characteristic of the convicts liberated from his old homestead at Sing Sing, it may well be asked, whether it may not prove to be some feeling, somehow akin to the reminiscent impulses which influenced them, that shall hereafter fraternally reunite all us mortals, when we shall have exchanged this State's Prison man-of-war world of ours for another and a better.
CHAPTER XXXVI. FLOGGING NOT NECESSARY.


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Take Advantage of Wellness Programs From Your Health Insurance
More in Health Insurance
Affordable Care Act & Obamacare
Prescription Drug Insurance
Financial Aid & Subsidies
Nancy Larson
JGI/Jamie Grill/Blend Images/Getty Images
While experts debate whether preventive measures lower healthcare costs on a national level, there's plenty of evidence that prevention is beneficial when it comes to your individual health—and your wallet.
Of the 10 most common causes of death, including heart disease and cancer, half are related to lifestyle choices, according to the Center for Bioethics and Human Dignity. Keeping your weight down, quitting smoking, staying fit and reducing stress are some of the best ways to prevent illness and prolong life, and they could reduce the amount of money you have to spend on hospitalization, drugs and other therapies.
If you have health insurance, you probably know that in most cases, preventive medical checkups—such as yearly physicals and OB/GYN visits—are covered. But you may not know that some plans also offer wellness options that may help pay for exercise or weight-loss programs.
Insurers Trending Toward Prevention
Gym memberships, weight-loss clinics, weight-loss surgery, massage therapy and stop-smoking programs are just a few of the items included in some insurance plans. Blue Cross Blue Shield of Massachusetts even offers a discount on electric toothbrushes to help prevent cavities.
More insurance companies have begun partnering with health clubs to offer discounted memberships or services. The benefits cover everyone, from the super-fit to those with chronic medical conditions, according to J.P. Wieske, of the Council for Affordable Insurance.
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Promoting Healthy People and Budgets
It pays to take advantage of any preventive benefits that come with your insurance policy. Some examples of possible savings include:
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Gym membership: Some United Health Care plans include 10 to 50% discounts on specific health club memberships. If your gym plan takes $30 a month out of your checking account, a half-off discount will save you $15 each month.
Weight-loss program: Not many policies cover weight-loss programs like Jenny Craig or Weight Watchers, but look for that to change in the future, Wieske says. One benefit now available through Aetna to Kraft Foods Inc. employees offers a 30% discount on such programs, which brings the cost of one popular $199 plan to $139.
Orthopedic massage: A one-hour, stress-busting therapeutic massage at Massachusetts Blue Cross Blue Shield participating facility Boston Bodyworker is normally $115, but the 25% insurance discount makes it $86. No documentation of any medical condition is necessary to get coverage.
Only a few insurers cover smoking-cessation programs and medications, which are mostly over-the-counter. But if you talk with your doctor about quitting during a routine physical, that visit will be covered. Those rare policies that do help with the cost of formal programs that include counseling can save you hundreds of dollars, on top of the $650 or so that pack-a-day smokers who kick the habit will save in a year's time.
To find out what wellness benefits you may have, contact your insurance company or your employer.
Bariatric Surgery for Severe Obesity. Mar. 2008. National Institutes of Health.
Health and Wellness. 2008. Blue Cross Blue Shield of Massachusetts.
Health Discounts. 2008. United Health Care.
Lap-Band Cost. 2008. Lap-Band lapband.us.
Preventive Card. 2008. Kraft Benefits.
Smoking Cessation Rates Double with Intensive Counseling and Free Nicotine Replacement Therapy, Studies of 20,000 Smokers Show. 29 Nov. 2007. Kaiser Permanente.
Take the First Steps for Weight Loss Surgery. 2008. Duke University.
The Adequacy of Preventive Health Care: Does the Health Care Provider Matter?. 2004. The Center for Bioethics Human Dignity.
What is Orthopedic Massage?. 2007. Boston Bodyworker.
Frequently Asked Medicare Questions
COBRA vs. Obamacare: Which Is Better?
What Is Direct Primary Care?
Do You Know Your Health Insurance Provider's Network?
What You Should Know About Platinum Plan Health Insurance
How to Find Affordable Health Coverage When Laid Off
An Overview of Medicare Eligibility and Benefits
What to Know About Universal Health Care Coverage
What Is Actuarial Value & What Does It Mean for My Health Insurance?
Catastrophic Health Insurance Overview
How To Get Help Paying for Health Insurance
What to Know About Gold Plan Health Insurance
What Do I Need to Know About Health Insurance Changes for 2020?
An Overview of Prescription Drug Insurance
What Is a Silver Health Care Plan Under the Affordable Care Act?
Pregnant With No Maternity Insurance? What Now?


text:
Q: GeoTIFF (ESA Copernicus data) georeferencing coordinates are mirrored and projection slightly off when checking on Google Maps I worked on downloading a Sentinel 5P data in my question at Converting a netCDF4 file to (georeferenced) GeoTIFF, problems with georeferencing and also transforming the netCDF4 (.nc) file into a geoTIFF image/raster data set.
As noted in the answer to my question, it appears the georeferencing method I use doesn't work correctly.

*

*Two of the corner points are flipped and for a reason or another I don't seem to get them correctly.

*I use Google Maps to check I have transformed the geoTIFF file correctly. In addition. The corner points are also slightly off of what Copernicus map shows. I assume this is a difference in the way they project the maps, but as the ultimate goal is to get the tiff on a common web map, I think I need to get this part right too.

Question: Can someone shed light on what's wrong with my projection parameters? The parameters are given in the following, first a bit of setup to make it easier to undersand what I was thinking.
I replicate the previous question here as appropriate for this one. In case it helps, the Copernicus portal is at https://s5phub.copernicus.eu/dhus/#/home. The guest username and password are given in a prompt when one presses login. It has a lot more tooling to fiddle with ideas, shapefiles amongst other things.
Let's assume a netCDF4 (.nc) file downloaded from https://s5phub.copernicus.eu/dhus/odata/v1/Products('e6e91b26-ca43-43d4-9c08-c9c14dd6737e')/$value . This is sulphur dioxide measurement dataset over Vietnam, China, Taiwan and Philippines, given in the linked image. Regarding the portal, searching with S5P_NRTI_L2__SO2____20181030T054006_20181030T054506_05418_01_010102_20181030T062719 yields the same data/file as downloading directly.

From the downloaded .nc file I can see in the metadata
geolocation_grid_from_band=3
geospatial_lat_max=25.532017
geospatial_lat_min=2.1418159
geospatial_lon_max=99.929924
geospatial_lon_min=128.72141

so I proceed the create a geoTIFF raster data file as follows: gdal_translate -ot float32 -unscale -CO COMPRESS=deflate -of GTiff -a_srs EPSG:4326 -a_ullr 25.532017 99.929924 2.1418159 128.72141 HDF5:"S5P_NRTI_L2__SO2____20181030T054006_20181030T054506_05418_01_010102_20181030T062719.nc"://PRODUCT/sulfurdioxide_total_vertical_column so2.tif
Applying these produces a geotiff file with the following georeferecing information
Corner Coordinates:
Upper Left  (      25.532,      99.930) ( 25d31'55.26"E, 99d55'47.73"N)
Lower Left  (      25.532,     128.721) ( 25d31'55.26"E,128d43'17.08"N)
Upper Right (       2.142,      99.930) (  2d 8'30.54"E, 99d55'47.73"N)
Lower Right (       2.142,     128.721) (  2d 8'30.54"E,128d43'17.08"N)
Center      (      13.837,     114.326) ( 13d50'12.90"E,114d19'32.40"N)

Where the Upper Left and Lower Right are approximately correct but otherwise Lower Left and Upper Right have switched places. Also comparing the ESA satellite image (linked) and then inserting the corner coordinates to Google Maps yield slightly different places on the map. I tried to project with EPSG:3857 already and I tried placing the corder coordinates in different order, no dice (as an aside, it'd be nice to know if this can be done without dumping metadata about the corner points first and applying the information specifically).
Here are the Google Maps links for the corner points for convenience:

*

*Upper Left: https://www.google.com/maps/place/25°31'55.2"N+99°55'48.0"E/@28.0950673,105.9647385,5.5z

*Lower Left (inverted): https://www.google.com/maps/place/25°31'55.2"N+128°43'15.6"E/@25.1936751,127.712565,7.5z/

*Upper Right (inverted): https://www.google.com/maps/place/2°08'31.2"N+99°55'48.0"E/@1.9855769,100.0484641,7.75z/

*Lower Right: https://www.google.com/maps/place/2°08'31.2"N+99°55'48.0"E/@1.9855769,100.0484641,7.75z/
<edit: With the proposed parameters -a_ullr 99.930 25.532017 128.72141 2.142 gdalinfo so2.tif gives
Corner Coordinates:
Upper Left  (  99.9300000,  25.5320170)
Lower Left  (  99.9300000,   2.1420000)
Upper Right ( 128.7214100,  25.5320170)
Lower Right ( 128.7214100,   2.1420000)
Center      ( 114.3257050,  13.8370085)

which doesn't seem be right. Looking at the coordinates, it gives a feeling the corners are on straight lines, like a square on a flat map. I'll be spelunking something with "spherical Mercator" soon, I suppose. Basically waving hands to every direction and seeing if something sticks. :P
<edit 5: Maybe it's something about snapping values to pixel colors, i.e. a drawing artifact. Here's another way of seeing the image after removing sentinel values:

<edit 4:
On QGIS looking at metadata about sentinel values and setting their opacity to 100% crops of the edges and reveals a black image that looks like the original. Then adjusting the histogram so that the maximum value is the highest measurement point gives the grey scale image in the picture. The black band on the left side seems to be all minimum values. I don't know the cause of this. It could be a projection artefact but it could also be invalid QA values that should be cropped off. Here's the image:

<edit 3:
I proceed with the instructions hinted by @AndreJ and run the following commands
gdal_translate -of VRT HDF5:"S5P_NRTI_L2__SO2____20181030T054006_20181030T054506_05418_01_010102_20181030T062719.nc"://PRODUCT/longitude lon.vrt
gdal_translate -of VRT HDF5:"S5P_NRTI_L2__SO2____20181030T054006_20181030T054506_05418_01_010102_20181030T062719.nc"://PRODUCT/latitude lat.vrt
gdal_translate -of VRT HDF5:"S5P_NRTI_L2__SO2____20181030T054006_20181030T054506_05418_01_010102_20181030T062719.nc"://PRODUCT/sulfurdioxide_total_vertical_column so2.vrt

And modify the resulting so2.vrt to read as follows
<VRTDataset rasterXSize="450" rasterYSize="278">
   <Metadata>
   <!-- Snipped off for brevity. -->
   </Metadata>
   <!-- Added this geolocation domain information. -->
   <Metadata domain="GEOLOCATION">
       <mdi key="X_DATASET">lon.vrt</mdi>
       <mdi key="X_BAND">1</mdi>
       <mdi key="Y_DATASET">lat.vrt</mdi>
       <mdi key="Y_BAND">1</mdi>
       <mdi key="PIXEL_OFFSET">0</mdi>
       <mdi key="LINE_OFFSET">0</mdi>
       <mdi key="PIXEL_STEP">1</mdi>
       <mdi key="LINE_STEP">1</mdi>
   </Metadata>
   <VRTRasterBand dataType="Float32" band="1">
   <Metadata>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column_coordinates">/PRODUCT/longitude /PRODUCT/latitude</MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column_long_name">total vertical column of sulfur dioxide for the polluted scenario derived from the total slant column</MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column_multiplication_factor_to_convert_to_DU">2241.1499 </MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column_multiplication_factor_to_convert_to_molecules_percm2">6.02214e+19 </MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column_standard_name">atmosphere_mole_content_of_sulfur_dioxide</MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column_units">mol m-2</MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column__FillValue">9.96921e+36 </MDI>
       <MDI key="PRODUCT_sulfurdioxide_total_vertical_column__Netcdf4Dimid">2 </MDI>
     </Metadata>
     <SimpleSource>
         <SourceFilename relativeToVRT="1">HDF5:S5P_NRTI_L2__SO2____20181030T054006_20181030T054506_05418_01_010102_20181030T062719.nc://PRODUCT/sulfurdioxide_total_vertical_column</SourceFilename>
         <SourceBand>1</SourceBand>
         <SourceProperties RasterXSize="450" RasterYSize="278" DataType="Float32" BlockXSize="450" BlockYSize="278" />
         <SrcRect xOff="0" yOff="0" xSize="450" ySize="278" />
         <DstRect xOff="0" yOff="0" xSize="450" ySize="278" />
      </SimpleSource>
 </VRTRasterBand>
 </VRTDataset>

Then running gdalwarp -geoloc -t_srs EPSG:4326 -overwrite so2.vrt so2.tif and finally gdalinfo so2.tif yields
Corner Coordinates:
Upper Left  ( 100.1267700,  25.0621347) (100d 7'36.37"E, 25d 3'43.69"N)
Lower Left  ( 100.1267700,   2.5234540) (100d 7'36.37"E,  2d31'24.43"N)
Upper Right ( 128.5601826,  25.0621347) (128d33'36.66"E, 25d 3'43.69"N)
Lower Right ( 128.5601826,   2.5234540) (128d33'36.66"E,  2d31'24.43"N)
Center      ( 114.3434763,  13.7927944) (114d20'36.51"E, 13d47'34.06"N)
Band 1 Block=493x4 Type=Float32, ColorInterp=Gray

which isn't correct. Interestingly the coordinates are "inverted" in that changing 100.1267700,  25.0621347 -> 25.0621347, 100.1267700 is approximately correct, albeit slightly offset when compared to the Copernicus image (looking the coordinates via Google Maps now). It doesn't appear the reason is solely about longitude and latitude information changed but also the projection is wrong.
Opened in QGIS and projected on Google Maps gives  which looks like being in the right place. The data is unscaled so nearly black (I assume), the white strand is an interesting looking thing (looks like being the edge of the original satellite picture, i.e. no data, but why black on the other side then?).
<edit 2: There's interesting discussion at https://github.com/stcorp/harp/issues/189 about possible issues. Even if the discussed issue isn't directly this, one should note it's about Sentinel 5P, georeferencing and invalid values in certain situations. For that I wonder if that's the case here and how to find those values and filter out. As a tangential educative issue, pay attention to vocabulary about level 1/2/3 products too, see more at https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-5p/products-algorithms.
<edit 1: In the metadata I see (I don't know if this matters):
PRODUCT_corner_CLASS=DIMENSION_SCALE
PRODUCT_corner_comment=This coordinate variable defines the indices for the pixel corners; index starts a 0 (counter-clockwise, starting from south-western corner of the pixel in ascending part of the orbit).
PRODUCT_corner_long_name=pixel corner index
PRODUCT_corner_NAME=corner
PRODUCT_corner_REFERENCE_LIST=
PRODUCT_corner_units=1
PRODUCT_corner__FillValue=-2147483647
PRODUCT_corner__Netcdf4Dimid=3
PRODUCT_delta_time_long_name=offset from reference start time of measurement
PRODUCT_delta_time_units=milliseconds
PRODUCT_delta_time__FillValue=-2147483647
PRODUCT_delta_time__Netcdf4Dimid=2
PRODUCT_ground_pixel_axis=X
PRODUCT_ground_pixel_CLASS=DIMENSION_SCALE
PRODUCT_ground_pixel_comment=This coordinate variable defines the indices across track, from west to east; index starts at 0
PRODUCT_ground_pixel_long_name=across-track dimension index
PRODUCT_ground_pixel_NAME=ground_pixel
PRODUCT_ground_pixel_REFERENCE_LIST=
PRODUCT_ground_pixel_units=1
PRODUCT_ground_pixel__FillValue=-2147483647
PRODUCT_ground_pixel__Netcdf4Dimid=1
PRODUCT_latitude_bounds=/PRODUCT/SUPPORT_DATA/GEOLOCATIONS/latitude_bounds
PRODUCT_latitude_long_name=pixel center latitude
PRODUCT_latitude_standard_name=latitude
PRODUCT_latitude_units=degrees_north
PRODUCT_latitude_valid_max=90
PRODUCT_latitude_valid_min=-90
PRODUCT_latitude__FillValue=9.96921e+36
PRODUCT_latitude__Netcdf4Dimid=2
PRODUCT_layer_CLASS=DIMENSION_SCALE
PRODUCT_layer_long_name=layer dimension index
PRODUCT_layer_NAME=layer
PRODUCT_layer_REFERENCE_LIST=
PRODUCT_layer_units=1
PRODUCT_layer__Netcdf4Dimid=4
PRODUCT_longitude_bounds=/PRODUCT/SUPPORT_DATA/GEOLOCATIONS/longitude_bounds
PRODUCT_longitude_long_name=pixel center longitude
PRODUCT_longitude_standard_name=longitude
PRODUCT_longitude_units=degrees_east
PRODUCT_longitude_valid_max=180
PRODUCT_longitude_valid_min=-180
PRODUCT_longitude__FillValue=9.96921e+36
PRODUCT_longitude__Netcdf4Dimid=2

A: In case this is useful to anyone, I created a Python script that replicates the accepted answer and that can be used on a number of S5p files for a list of variables, without having to manually edit the vrt file. The code is available here, but I also copy-paste below.
EDIT: I updated the code to automatically mask invalid pixels based on the qa_value subdataset stored in the NETCDF file.
import os
import subprocess
from osgeo import gdal
import numpy as np

def write_s5p_tif(in_filepath, variables, output_folder, EPSG_code="4326", spatial_res=[]):
    """
    Write specified variables of S5p NETCDF file to a georeferenced GTiff file
    in Pseudo-Mercator with spatial resolution 3500m x 7000m.

    Parameters
    ----------
    in_filepath: str
        full filepath to S5p NETCDF file (.nc)
    variables: list of str
        list of variables in the S5p NETCDF file that will be written to GTiff files
    EPSG_code: str
        EPSG code of desired projection, default is 3857 (Pseudo-Mercator)
    spatial_res: list of float
        X and Y spatial resolution (sampling) in degrees or meters according to the chosen projection
        Defaults to 3500m x 7000m (or degree equivalent scaled by mean latitude)

    """

    kwargs = {}
    kwargs['EPSG_code'] = EPSG_code
    kwargs['spatial_res'] = spatial_res

    # Create vrt files for latitude and longitude variables
    geo_params = {}
    geo_params['outputSRS'] = f"EPSG:{EPSG_code}"
    gdal.Translate("lat.vrt", f'HDF5:"{in_filepath}"://PRODUCT/latitude', **geo_params)
    lat_ds = gdal.Open("lat.vrt")
    lats = lat_ds.ReadAsArray()
    gdal.Translate("lon.vrt", gdal.Open(f'HDF5:"{in_filepath}"://PRODUCT/longitude'), **geo_params)

    ds = gdal.Open(in_filepath)
    md = ds.GetMetadata()

    data_var = "temp_s5p.tif"
    mask_var = "qa_value.tif"
    output_file = generate_out_filepath(in_filepath, output_folder, ".tif")

    for variable in variables:
        # Georeference variable datset
        write_var_to_tif(data_var, in_filepath, variable, "lon.vrt", "lat.vrt", lat_ds,
                      **kwargs)
        # Georeference quality_value datset
        write_var_to_tif(mask_var, in_filepath, "qa_value", "lon.vrt", "lat.vrt", lat_ds,
                      **kwargs)
        # Apply quality mask to variable dataset
        write_masked_data(output_file, data_var, mask_var, mask_threshold=75)

        # Clean
        os.remove(data_var)
        os.remove(data_var.split('.')[0] + '_.vrt')
        os.remove(mask_var)
        os.remove(mask_var.split('.')[0] + '_.vrt')

    # Remove vrt files
    os.remove('lon.vrt')
    os.remove('lat.vrt')

def write_var_to_tif(out_filepath, in_filepath, variable, lon_file, lat_file, ds, **kwargs):
    """

    """

    vrt_filepath = out_filepath.split('.')[0] + '_.vrt'

    with open(vrt_filepath, "w") as text_file:
        text_file.write(f"""
<VRTDataset rasterXSize="{ds.RasterXSize}" rasterYSize="{ds.RasterYSize}">
    <metadata domain="GEOLOCATION">
        <mdi key="X_DATASET">{lon_file}</mdi>
        <mdi key="X_BAND">1</mdi>
        <mdi key="Y_DATASET">{lat_file}</mdi>
        <mdi key="Y_BAND">1</mdi>
        <mdi key="PIXEL_OFFSET">0</mdi>
        <mdi key="LINE_OFFSET">0</mdi>
        <mdi key="PIXEL_STEP">1</mdi>
        <mdi key="LINE_STEP">1</mdi>
    </metadata>
    <VRTRasterBand band="1" datatype="Float32">
        <SimpleSource>
            <SourceFilename relativeToVRT="0">HDF5:{in_filepath}://PRODUCT/{variable}</SourceFilename>
            <SourceBand>1</SourceBand>
            <SourceProperties RasterXSize="{ds.RasterXSize}" RasterYSize="{ds.RasterYSize}" DataType="Float32" BlockXSize="{ds.RasterXSize}" BlockYSize="{ds.RasterYSize}" />
            <SrcRect xOff="0" yOff="0" xSize="{ds.RasterXSize}" ySize="{ds.RasterYSize}" />
            <DstRect xOff="0" yOff="0" xSize="{ds.RasterXSize}" ySize="{ds.RasterYSize}" />
        </SimpleSource>
    </VRTRasterBand>
</VRTDataset>
""")

    # Add georeferencing to vrt file
    georef_data(out_filepath, vrt_filepath, vrt=False, **kwargs)

def write_masked_data(out_filepath, data_file, mask_file, mask_threshold=75):
    """

    """

    data_ds = gdal.Open(data_file)
    data = data_ds.ReadAsArray()
    mask = gdal.Open(mask_file).ReadAsArray()
    data[mask <= mask_threshold] = np.nan

    driver = gdal.GetDriverByName('GTiff')
    dataset = driver.Create(
        out_filepath,
        data_ds.RasterXSize,
        data_ds.RasterYSize,
        1,
        gdal.GDT_Float32, )

    dataset.SetGeoTransform(data_ds.GetGeoTransform())
    dataset.SetProjection(data_ds.GetProjectionRef())
    dataset.GetRasterBand(1).WriteArray(data)
    dataset.FlushCache()  # Write to disk.

def georef_data(out_filepath, in_filepath, vrt, EPSG_code, spatial_res):
    """

    """

    params = {}
    #params['geoloc'] = True
    #params['srcNodata'] = float(md[f"PRODUCT_{variable}__FillValue"])
    params['dstNodata'] = -9999
    params['dstSRS'] = f"EPSG:{EPSG_code}"
    if vrt:
        params["format"] = "VRT"
        #ext = ".vrt"
        out_filepath = out_filepath.replace('.tif', '.vrt')
    else:
        params["format"] = "Gtiff"
        #ext = ".tif"
        out_filepath = out_filepath.replace('.vrt', '.tif')
    if not spatial_res:
        if EPSG_code == "4326":
            params['xRes'] = 0.06288  # equivalent to 7000 meters
            params['yRes'] = 0.06288  # equivalent to 7000 meters
        else:
            params['xRes'] = 7000  # meters
            params['xRes'] = 7000  # meters
    else:
        params['xRes'] = spatial_res[0]
        params['xRes'] = spatial_res[1]

    #out_filepath = generate_out_filepath(in_filepath, output_folder, ext)
    gdal.Warp(out_filepath, in_filepath, **params)

def generate_out_filepath(in_filepath, output_folder, ext):
    """

    ext: '.tif', '.vrt'

    """

    filename = in_filepath.split(os.path.sep)[-1]
    var_name_short = filename[13:20].replace('_','')
    timestamp = filename[20:35]
    return output_folder + os.path.sep + var_name_short + '_' + timestamp + ext

def merge_rasters(in_filenames, output_filename):
    """

    """

    cmd_gdal_merge = " ".join([
                                'gdal_merge.py', '-init 255 -o', output_filename, \
                                '-n 9999' \
                                ] + \
                                ['"%s"' % in_filename for in_filename in in_filenames])
    subprocess.check_output(cmd_gdal_merge, shell=True)

Once saved as a file, one can import the function 'write_s5p_tif' and use it this way:
write_s5p_tif('S5P_OFFL_L2__NO2____20191222T123026_20191222T141156_11352_01_010302_20191224T055628.nc', ['nitrogendioxide_tropospheric_column'], '/path/to/folder')

A: I think you are already there. I got the same extent as you, and this image:

Note that the extent of the warped tif is now a rectangle in EPSG:4326, with corners different to the bended satellite view.
The blue dashed line I got from the METADATA_EOP_METADATA_om:featureOfInterest_eop:multiExtentOf_gml:surfaceMembers_gml:exterior_gml:posList variable (which uses lat-lon order).
Keep in mind that cell center coordinates and raster extent differ by half the cell size.

Update
As requested, this is my batch file:
 gdal_translate -of VRT HDF5:"s5p.nc"://PRODUCT/latitude lat.vrt
 gdal_translate -of VRT HDF5:"s5p.nc"://PRODUCT/longitude lon.vrt
 gdal_translate -of VRT HDF5:"s5p.nc"://PRODUCT/sulfurdioxide_total_vertical_column s5p.vrt
 gdalwarp -geoloc -t_srs EPSG:4326 -srcnodata 9.96921e+36 -dstnodata 9999 s5p.vrt s5p.tif

and the modified vrt file:
 <VRTDataset rasterXSize="450" rasterYSize="278">
 <metadata domain="GEOLOCATION">
 <mdi key="X_DATASET">lon.vrt</mdi>
 <mdi key="X_BAND">1</mdi>
 <mdi key="Y_DATASET">lat.vrt</mdi>
 <mdi key="Y_BAND">1</mdi>
 <mdi key="PIXEL_OFFSET">0</mdi>
 <mdi key="LINE_OFFSET">0</mdi>
 <mdi key="PIXEL_STEP">1</mdi>
 <mdi key="LINE_STEP">1</mdi>
 </metadata>
 <VRTRasterBand band="1" datatype="Float32">
 <SimpleSource>
  <SourceFilename relativeToVRT="1">HDF5:s5p.nc://PRODUCT/sulfurdioxide_total_vertical_column</SourceFilename>
  <SourceBand>1</SourceBand>
  <SourceProperties RasterXSize="450" RasterYSize="278" DataType="Float32" BlockXSize="450" BlockYSize="278" />
  <SrcRect xOff="0" yOff="0" xSize="450" ySize="278" />
  <DstRect xOff="0" yOff="0" xSize="450" ySize="278" />
 </SimpleSource>
 </VRTRasterBand>
 </VRTDataset>

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An overwater bungalow resort might be among the dreamiest of honeymoon destinations. Here are a few that won't break the bank.
If your idea of the perfect honeymoon involves being perched atop pristine waters in one of the most amazing overwater bungalow resorts in the world, you're probably trying to save up every single penny leftover from your wedding budget to cover the costs. Yes, this kind of honeymoon is on the pricier side given the luxurious nature of floating over the ocean in utter seclusion while being waited on hand and foot by a caring staff, but that's not to say honeymoon huts are out of the cards if you're not a Kardashian. In fact, there are plenty of overwater bungalow resorts that cater to honeymooners dealing with all sorts of budgets.
Here are some overwater bungalow resorts that top the list and offer cozy and romantic honeymoon huts at reasonable prices.
Located in the volcanic cliffs of Negril, Jamaica's Pristine Cove, this resort literally dangles over the azure Caribbean sea. If that's not jaw-dropping enough, the honeymoon huts' rustic-chic decor made from local raw materials and stone, as well as their thatched roof will surely give you all the Jamaica honeymoon feels. Believe it or not, each individual villa sells for $250 a night during the fall season, featuring private wraparound balconies and open-air showers. Honeymooners are welcomed with a complimentary bottle of bubbly, scented candles and flower petals on the bed.
Heralded as the first over-the-ocean suites in all of Mexico, this honeymoon hot spot consists of 30 elegant Palafitos, or elite overwater bungalows surrounded by the bright turquoise waters of Riviera Maya's Maroma Beach. Each Palafitos features breathtaking views that can be leisurely admired while honeymooners are enjoying the spacious private infinity pools, glass-bottom floors, outdoor showers, direct ladder ocean access and an overwater restaurant and overwater spa on the premises. Although the rates start at $951 per person, per night, this includes all gourmet food, premium alcoholic beverages, 24-hour room service, a personal Majordomo to cater to each and every need, and much more, so pretty much all your other expenses are covered!
When you first think of the central European country of Switzerland, you might picture snow-capped mountains, ski resorts and hiking trails, but there is one overwater bungalow resort. In fact, Hôtel Palafitte, set on lake Neuchatel, the largest lake in Switzerland, is the only hotel in Europe built on stilts. It was initially constructed as part of the National Expo in 2002, but the temporary hotel was so successful that the owners decided to keep the bungalows operational. There are breathtaking views surrounding each unit, with descending ladders from the room's balconies directly into the lake. Honeymooners can enjoy water activities on the lake, direct access to hiking trails from the hotel grounds, biking, nearby chocolate houses, skiing breweries and wineries.
If you've done any research on honeymoon resorts in the Maldives, a tiny tropical nation in the Indian Ocean, you know it's hardly affordable. But this overwater bungalow resort offers rates that hover around $440 each night depending on your package. Each honeymoon hut comes with your own private deck looking out into the beautiful, crystal clear waters, outdoor shower and outdoor hot tub, as well as a cut-out portion of the deck that has netting similar to an overwater hammock. Adventurous couples will love that the resort offers a complimentary snorkeling tour in addition to many other activities like a dolphin cruise, turtle snorkeling, whale shark snorkeling and more.
Put aside the image in your head of the traditional Mexican resort featuring high-rise, corridor or box-like buildings. You'll, instead, find a more ethereal, authentic and raw-luxe honeymoon retreat at Playa del Carmen's Mahekal Beach Resort. As you walk down their hand-laid, hidden stone pathways, you'll find 196 private, palapa-style bungalows nestled comfortably between the dense jungle of the Riviera Maya and Playa del Carmen's longest stretch of beach, spanning 920 feet. Ocean front "casitas," or beach house bungalows are available directly on the beach featuring open-air terraces with crochet hammocks, personal plunge pools or private outdoor moon showers and rates starting at $350 a night.
If you're looking to celebrate your honeymoon surrounded by the clear-blue waters of the Caribbean, why not stay at one of the only two resorts to have pole housing toeing the shore. Each beach house is raised on stilts above the sand with two bedrooms, ensuite baths, full size kitchens, living rooms and private decks with pool, wraparound balustrade and a drop down staircase to the private beach below. Your daily view will be looking out to neighboring island St. Kitts! and have a drop down staircase to the private beach below. Fun added incentive: Nevis is speculated to be the royal honeymoon destination of Prince Harry and Meghan Markle!
If you're looking for a true island escape that will melt away all of the stresses of wedding planning, a French Polynesia honeymoon will offer you just that and more. The one problem with this popular honeymoon destination (which celebrities are known to frequent, might we add!) is that the majority of resorts are hardly affordable (unless you're Nicole Kidman and Keith Urban who notoriously honeymooned there). That is, except for the Royal Huahine, which offers 18 garden bungalows, 11 beach bungalows and 11 overwater bungalows amongst stunningly gorgeous settings for a whopping $300 per night for two!


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Nehemiah, a Decided Reformer
"Remember me, O my God, for good" (Nehemiah 13:31).
"Through [Nehemiah] . . . God purposed to bring blessing to His people in the land of their fathers."—Conflict and Courage, p. 262.
1. GOD HELPS NEHEMIAH
a. Who was Nehemiah? What news did he receive from Jerusalem that led him to mourn, fast, and pray? Nehemiah 1:2–5.
"Nehemiah had often poured out his soul in behalf of his people. But now as he prayed a holy purpose formed in his mind. He resolved that if he could obtain the consent of the king, and the necessary aid in procuring implements and material, he would himself undertake the task of rebuilding the walls of Jerusalem and restoring Israel's national strength. And he asked the Lord to grant him favor in the sight of the king, that this plan might be carried out."—Prophets and Kings, pp. 629, 630.
b. How long had Nehemiah waited for an opportunity to talk to the king about his need? Relate their conversation. Nehemiah 2:2, 3.
c. How did Nehemiah's prayer bring the power of the Almighty to his aid? How did he pray? Nehemiah 2:4–6.
2. IMPORTANT LESSONS FOR US
a. What lesson should we learn from Nehemiah's prayer? Nehemiah 2:4 (last part).
"To pray as Nehemiah prayed in his hour of need is a resource at the command of the Christian under circumstances when other forms of prayer may be impossible. Toilers in the busy walks of life, crowded and almost overwhelmed with perplexity, can send up a petition to God for divine guidance. Travelers by sea and land, when threatened with some great danger, can thus commit themselves to Heaven's protection. In times of sudden difficulty or peril the heart may send up its cry for help to One who has pledged Himself to come to the aid of His faithful, believing ones whenever they call upon Him. In every circumstance, under every condition, the soul weighed down with grief and care, or fiercely assailed by temptation, may find assurance, support, and succor in the unfailing love and power of a covenant-keeping God."—Prophets and Kings, pp. 631, 632.
b. Explain Nehemiah's care to obtain a clear definition of his authority and of the privileges granted him? Nehemiah 2:7–9.
"This example of [Nehemiah's] wise forethought and resolute action should be a lesson to all Christians. God's children are not only to pray in faith, but to work with diligent and provident care. They encounter many difficulties and often hinder the working of Providence in their behalf, because they regard prudence and painstaking effort as having little to do with religion. Nehemiah did not regard his duty done when he had wept and prayed before the Lord. He united his petitions with holy endeavor, putting forth earnest, prayerful efforts for the success of the enterprise in which he was engaged. Careful consideration and well-matured plans are as essential to the carrying forward of sacred enterprises today as in the time of the rebuilding of Jerusalem's walls. . . .
"And the Lord is still willing to move upon the hearts of those in possession of His goods, in behalf of the cause of truth. Those who labor for Him are to avail themselves of the help that He prompts men to give."—Ibid., pp. 633, 634.
3. LEARNING TO WORK FOR GOD
a. What was Nehemiah's first work in Jerusalem, and how did he gain the cooperation of the local people? Nehemiah 2:11–16.
"In secrecy and silence Nehemiah completed his circuit of the walls. [Nehemiah 2:16 quoted.] The remainder of the night he spent in prayer; for he knew that the morning would call for earnest effort to arouse and unite his dispirited and divided countrymen.
"Nehemiah bore a royal commission requiring the inhabitants to cooperate with him in rebuilding the walls of the city, but he did not depend upon the exercise of authority. He sought rather to gain the confidence and sympathy of the people, knowing that a union of hearts as well as of hands was essential in the great work before him."—Prophets and Kings, pp. 636, 637.
b. What appeal did Nehemiah make to the people, and what was their response? Nehemiah 2:17, 18.
"When on the morrow he called the people together he presented such arguments as were calculated to arouse their dormant energies and unite their scattered numbers.
"Nehemiah's hearers did not know, neither did he tell them, of his midnight circuit of the night before. But the fact that he had made this circuit contributed greatly to his success; for he was able to speak of the condition of the city with an accuracy and a minuteness that astonished his hearers. The impression made upon him as he had looked upon the weakness and degradation of Jerusalem gave earnestness and power to his words. . . .
"Having shown that he was sustained by the combined authority of the God of Israel and the Persian king, Nehemiah asked the people directly whether they would take advantage of this opportunity and arise and build the wall.
"The appeal went straight to their hearts. The thought of how Heaven's favor had been manifested toward them put their fears to shame. . . .
"Nehemiah's whole soul was in the enterprise he had undertaken. His hope, his energy, his enthusiasm, his determination, were contagious, inspiring others with the same high courage and lofty purpose."—Ibid., pp. 637, 638.
4. OPPOSITION FROM THE ENEMIES
a. What method will some use to hide their anger or fear? When the enemies of Israel heard that the Jews had again started to build, how did they laugh at them? Nehemiah 4:1–4.
b. When the enemies of Israel saw that their fears were coming true, what plan did they adopt? Nehemiah 4:11. How did Satan try to discourage the builders through the Jews that refused to collaborate in the work? Nehemiah 4:12.
"Discouragement came from still another source. 'The Jews which dwelt by,' those who were taking no part in the work, gathered up the statements and reports of their enemies and used these to weaken courage and create disaffection."—Prophets and Kings, p. 643.
c. What happened when the Jews were informed the plan of their enemies? Instead of being intimidated, under what conditions did they continue the work? Nehemiah 4:15–18.
"The opposition and discouragement that the builders in Nehemiah's day met from open enemies and pretended friends is typical of the experience that those today will have who work for God. Christians are tried, not only by the anger, contempt, and cruelty of enemies, but by the indolence, inconsistency, lukewarmness, and treachery of avowed friends and helpers. Derision and reproach are hurled at them. And the same enemy that leads to contempt, at a favorable opportunity uses more cruel and violent measures.
"Satan takes advantage of every unconsecrated element for the accomplishment of his purposes. Among those who profess to be the supporters of God's cause there are those who unite with His enemies and thus lay His cause open to the attacks of His bitterest foes. . . . But, like Nehemiah, God's people are neither to fear nor to despise their enemies. Putting their trust in God, they are to go steadily forward, doing His work with unselfishness, and committing to His providence the cause for which they stand."—Ibid., pp. 644, 645.
5. DETECTING SATAN'S PLANS
a. What happened when the enemies of Israel realized the Jews had almost completed the wall? How did the enemies change their tactics? Nehemiah 6:1–3.
"Pretending to desire a compromise of the opposing parties, [Sanballat and his confederates] sought a conference with Nehemiah, and invited him to meet them in a village on the plain of Ono. But enlightened by the Holy Spirit as to their real purpose, he refused."—Prophets and Kings, p. 653.
b. What new stratagem did Sanballat and his confederates use? What did Nehemiah answer them? Nehemiah 6:5–8. What mistake was Nehemiah careful to avoid?
"He who by any unguarded act exposes the cause of God to reproach, or weakens the hands of his fellow workers, brings upon his own character a stain not easily removed, and places a serious obstacle in the way of his future usefulness."—Ibid., p. 659.
c. Describe the outpouring of emotion upon the completion of the wall and the gates. Nehemiah 8:16, 17. How did the enemies of the people of God feel? Nehemiah 6:15, 16.
1. What did Nehemiah do before answering King Artaxerxes?
2. How did Nehemiah exercise care in all the arrangements?
3. What did the reformer do first in Jerusalem—and why?
4. How can we gain advantage over the tactics of Satan today—just as the builders of the wall did in their time?
5. What was Nehemiah able to detect about the enemies?


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Hardcore hip hop
Hardcore hip hop (also hardcore rap) is a genre of hip hop music that developed through the East Coast hip hop scene in the 1980s. Pioneered by such artists as Kool G Rap, 2Pac, Schoolly D, Spoonie Gee, Boogie Down Productions, Public Enemy, The Earl (Thomas Dent), Nas, and N.W.A, it is generally characterised by anger, aggression, and confrontation.
Run-D.M.C. have been credited as the first hardcore hip hop group. Other early artists to adopt an aggressive style were Schoolly D in Philadelphia and Too $hort in Oakland. Before a formula for gangsta rap had developed, artists such as Boogie Down Productions and Ice-T wrote lyrics based on detailed observations of "street life", while the chaotic, rough style of Public Enemy's records set new standards for hip hop production. In the early 1990s, hardcore rap became largely synonymous with West Coast gangsta rap, with artists like 2Pac infusing Gangsta themed stories of gritty gang life. N.W.A and the Wu-Tang Clan emerged in the early 90's. Wu Tang Clan's minimalistic beats and piano-driven sampling became widely popular among other hip hop artists of the time, such as Onyx, House Of Pain, Ras Kass and Cypress Hill.
Gangsta rap has been associated with the style; however, not all hardcore hip hop revolve around "gangsta" lyrical themes, even though there is a great deal of overlap, especially among hardcore rappers of the 1990s. Hardcore Hip hop is characterised by aggression and confrontation and generally describes violence or anger. Russell Potter wrote that while hardcore rap has been associated with a "monolithic 'gangsta' outlook" by the popular press, hardcore rappers have "laid claim to a wide variety of ground".
Hardcore rap & hip hop artists
Army of the Pharaohs
Big L
Big Pun
Boogie Down Productions
Boot Camp Clik
Canibus
Capone-N-Noreaga
Celph Titled
Chino XL
Diggin' in the Crates Crew
El-P
Esham
Gravediggaz
Heltah Skeltah
Hoodratz
Ill Bill
Immortal Technique
Insane Poetry
Jadakiss
Jarren Benton
Jedi Mind Tricks
Junior M.A.F.I.A.
Jus Allah
Just-Ice
Lil Boosie
Lord Finesse
Killer Mike
The LOX
Kurt Rock
K-Rino
Miilkbone
N.W.A
Non Phixion
O.G.C.
Prozak
R.A. the Rugged Man
Rakim
Ras Kass
Remy Ma
Roxanne Shante
Schoolly D
Smif-n-Wessun
Smooth Da Hustler
Sticky Fingaz
Suprême NTM
Tim Dog
Geto Boys
Vinnie Paz
Webbie
Westside Connection
YG'z
Denzel Curry
Unless indicated otherwise, the text in this article is either based on Wikipedia article "Hardcore hip hop" or another language Wikipedia page thereof used under the terms of the GNU Free Documentation License; or on original research by Jahsonic and friends. See Art and Popular Culture's copyright notice.
Retrieved from "http://www.artandpopularculture.com/Hardcore_hip_hop"
This page was last modified 08:02, 19 January 2016.


text:
Q: Possible mistake in Cohen notes "Immersions of manifolds and homotopy theory" (version 27 March 2022) In Theorem 2  of  these notes, Ralph Cohen reformulates the main theorem of Hirsch-Smale theory merely in terms of normal bundles.
In particular,  he says that if $N, M$ are two manifolds, $\dim N< \dim M$ then two immersions
$f_1, f_2:N\to M$ are  regularly homotopic if and only if their normal bundles $\nu(f_1)$ and $\nu(f_2)$ are isomorphic.

Why it is enough to have isomorphic normal bundle to have regularly homotopic immersions? In other words, how does the if  part of the statement follows from the classical formulation of the Hirsch-Smale theorem?

I recall that the celebrated Hirsch-Smale theorem states that if $\dim N< \dim M$ or $N$ open, then the tangential map gives a bijection between the connected components
$$\pi_0(Imm(N,M)) \to \pi_0(Mono(TN,TM))$$
where $Imm(N,M) $ is the set of immersions and $Mono(TN,TM)$ is the set of monomorphisms (bundle maps $TN\to TM$ injective fiberwise).
My thoughts
Now, assume that $\nu(f_1)\simeq \nu(f_2)$ are isomorphic to some $\nu\to N$.
In view of Hirsch-Smale's theorem, we would like to show that $df_1: TN\to TM$ and $df_2:TN\to TM$ are homotopic through monomorphisms.
The hypothesis imply the existence of  two isomorphisms
$$F_i: TN\oplus \nu \to TM$$
for $i=1,2$, where $F_i|_{TN} = df_i$.
Clearly, if we show that $F_1$ and $F_2$ are homotopic through isomorphisms, then $df_1$ and $df_2$ are homotopic through monomorphisms so we are done.
However I don't see any good reason why $F_1$ should be homotopic to $F_2$.
Notice that we only know that $\nu(f_1)\simeq \nu(f_2)$ but we have some freedom in choosing the embedding $\nu\to TM$, constructing different $F_1, F_2$. It is enough to show that any of these are homotopic.
A special case
Let's study a special case, when $N =\mathbb S^n$ and  $TM\simeq \varepsilon^m$ is trivial. Then we are given two trivializations  $F_1, F_2$ of $TN\oplus \nu$, and we would like to show that these are homotopic (through trivialization).
An (oriented) trivialization is a section of the bundle of oriented $n+v$-frames, $SO(TN\oplus \nu)\to N$, where $v= \mathrm{rank} (\nu)$. Which has fiber $SO(n+v)$.
The obstructions to construct an homotopy lie $H^i(\mathbb S^n, \pi_i(SO(n+v))$, thus the obstruction to homotoping $F_1$ to $F_2$ lies in $\pi_n((SO(n+v)))$ (provided the two are cooriented).
However the latter homotopy group is in general non-trivial.
As I said above, we have some freedom, i.e. we can change the trivialization $F_1:TN\oplus \nu \to \varepsilon^m$, by twisting it with  an automorphism of $Aut(\nu)$, thus to conclude it would be sufficient to show that $\pi_n(SO(v))$ acts transitively on $\pi_n(SO(n+v))$ where the action is induced by multiplication by $A\in SO(v)\subset SO(n+v)$ (the inclusion is $A\to \begin{bmatrix} 1 & 0\\ 0& A\end{bmatrix}$).

A: The statement is false in two ways. First, two immersions might not even be homotopic even though their normal bundles are both, say, trivial. Second, even if $M=\mathbb R^m$, regular homotopy classes of immersions of $N$ correspond to homotopy classes of vector bundle monomorphisms from $TN$ to the trivial rank $m$ bundle. Two such monomorphisms can lead to isomorphic normal bundles without being homotopic. You can already see counterexamples with $n=S^1$ and $m=2$.


text:
\section{Introduction and Related Work}

Simulators are crucial tools for planning and control algorithms to tackle difficult real world robotics problems. In many cases, however, such models diverge from reality in important ways, leading to algorithms that work well in simulation and fail in reality. Closing the sim2real gap has gained significant interest, and various dynamics modeling approaches have been proposed (\autoref{fig:approaches} left).

Various methods learn system dynamics from time series data of a real system. Such ``intuitive physics'' models often use deep graph neural networks to discover constraints between particles or bodies~\cite{battaglia2016interaction, xu2019physics, he2019physics, raissi2018physics, mrowca2018physics, chen2018neural, li2018learning, sanchezgonzalez2020learning}.
We propose a general-purpose hybrid simulation approach that combines analytical models of dynamical systems with data-driven residual models that learn parts of the dynamics unaccounted for by the analytical simulation models.

Originating from traditional physics engines~\cite{coumans2013bullet,todorov2012mujoco,lee2018dart}, differentiable simulators have been introduced that leverage automatic, symbolic or implicit differentiation to calculate parameter gradients through the analytical physics models for rigid-body dynamics~\cite{giftthaler2017autodiff,carpentier2018analytical,peres2018lcp, koolen2019rbd-julia, heiden2019ids, heiden2019real2sim}, light propagation~\cite{NimierDavidVicini2019Mitsuba2, heiden2020lidar}, and other phenomena~\cite{hu2020difftaichi,liang2019differentiable}.

Residual physics models~\cite{zeng2019tossingbot,anurag2018hybrid,hwangbo2019learning,golemo2018neuralaugsim} augment physics engines with learned models to reduce the sim2real gap. Most of them introduce residual learning applied to the output of the physics engine, while we propose a more fine-grained approach, similar to Hwangbo et al.~\cite{hwangbo2019learning}, where only at some parts in the simulator data-driven models are introduced. While in~\cite{hwangbo2019learning} the network for actuator dynamics is trained through supervised learning, our end-to-end differentiable model allows backpropagation of gradients from high-level states to any part of the computation graph, including neural network weights, so that these parameters can be optimized efficiently, for example from end-effector trajectories.

\begin{figure}
    \centering
    \includegraphics[height=3.5cm, clip, trim=3cm 1cm 1cm 2cm]{neural_contact.png}\hfill
    \includegraphics[height=4.5cm]{ibm_pendulum_estimation.pdf}
    \caption{\emph{Left:} Trajectories from rigid body contact simulation of a cube thrown to the right. Starting with poor model parameters, the box falls through the ground (blue). After optimizing \autoref{eq:sim2rel_loss}, our simulation (orange) closely matches the target trajectory (green). \emph{Right:} After system identification of a real double pendulum~\cite{asseman2018learning}, the sim2real gap is strongly reduced.}
    \label{fig:results}
\end{figure}

\begin{figure*}[ht!]
    \centering
    \includegraphics[height=4.5cm]{system_comparison.pdf}\hfill
    \includegraphics[height=4.5cm]{nn_scalar.pdf}
    \caption{\textit{Left:} comparison of various model architectures (cf.~Anurag et al.~\cite{anurag2018hybrid}). \textit{Right:} augmentation of differentiable simulators with our proposed neural scalar type where variable $e$ becomes a combination of an analytical model $\phi(\cdot,\cdot)$ with inputs $a$ and $b$, and a neural network whose inputs are $a$, $c$, and $d$.}
    \label{fig:approaches}
\end{figure*}
\vspace*{-1cm}

\section{Approach}
We propose a technique for hybrid simulation that leverages differentiable physics models and neural networks to allow for efficient system identification, design optimization, and gradient-based trajectory planning. By enabling any part of the simulation to be replaced or augmented by neural networks, we can learn unmodeled effects from data. Through template meta-programming, our open-source C++ implementation\footnote{\url{https://github.com/google-research/tiny-differentiable-simulator}} allows any variable participating in the simulation to be augmented by neural networks that accept input connections from any other variable. In the simulation code, such \emph{neural scalars} (\autoref{fig:approaches} right) are assigned a unique name, so that in a separate experiment code a ``neural blueprint'' is defined that declares the neural network architectures and sets the network weights. We compute gradients of the weights and analytical simulation parameters using the multi-dimensional dual number implementation from Ceres~\cite{ceres-solver} and have support for many other automatic differentiation libraries.

\begin{table}[]
    \resizebox{\columnwidth}{!}{%
    \begin{tabular}{p{3.8cm}cccc}
    \toprule
    & \bf Analytical & \bf Data-driven & \bf End2end $\nabla$ & \bf Hybrid \\\midrule
    Physics engine~\cite{coumans2013bullet,todorov2012mujoco,lee2018dart} & \checkmark \\
    Residual physics~\cite{hwangbo2019learning,anurag2018hybrid,zeng2019tossingbot,golemo2018neuralaugsim} & \checkmark & \checkmark & & \checkmark \\
    Learned physics~\cite{sanchez2020learning,battaglia2016interaction,li2018learning,jiang2018datacontact} & & \checkmark & \checkmark \\
    Differentiable sim.~\cite{giftthaler2017autodiff,hu2020difftaichi,carpentier2018analytical,peres2018lcp} & \checkmark & & \checkmark \\
    Ours & \checkmark & \checkmark & \checkmark & \checkmark \\
\bottomrule
    \end{tabular}
    }
    \caption{Comparison of dynamics modeling approaches (only selected works) along the axes of analytical and data-driven modeling, end-to-end differentiability, and hybrid approaches.}
    \label{tab:comparison}
\end{table}

\section{System Identification}

Given the state trajectory $\{s^*_t\}_{t=1}^T$ from the target system, we optimize the following loss for system identification:
\begin{align}
\label{eq:sim2rel_loss}
\underset{\theta = [\theta_{AM}, \theta_{NN}]}{\operatorname{minimize}} ~~ \mathcal{L} = \sum_t ||f_\theta(s_{t-1}) - s^*_t||^2 + R||\theta_{NN}||^2,
\end{align}
where $f_\theta(\cdot)$ is the discrete dynamics function mapping from the previous simulation state $s_{t-1}$ to the current state $s_t$ which is implemented by our physics engine given the parameter vector $\theta$ that consists of the parameters $\theta_{AM}$ for the analytical model, plus the parameters $\theta_{NN}$ that correspond to the weights of the neural networks in the simulation. To ensure the residual dynamics learned by the neural networks are minimal, we regularize the network weights by factor $R$ which penalizes large state contributions.

\section{Overcoming Local Optima}
We solve the nonlinear least squares problem from \autoref{eq:sim2rel_loss} using the Levenberg-Marquardt algorithm (LMA). Such a gradient-based optimization method quickly finds local optima, but due to the highly nonconvex loss landscapes commonly encountered in system identification problems for nonlinear dynamics, the resulting parameter estimates often exhibit a poor fit to the real world data. To escape such poor local minima, we adapt a random search strategy, \emph{parallel basin hopping} (PBH)~\cite{mccarty2018parallel}, that, in our instantiation, runs multiple LMA solver and simulation instances in parallel while continuously randomizing the initial parameters from which the local solvers are restarted after convergence criteria, time limits, or maximum iteration counts are met.

\section{Results}
We present preliminary results for sim2sim transfer to match the hybrid dynamics model to richer analytical simulations. Additionally, we demonstrate our system identification approach on a real-world dataset.

In our first experiment, we transfer rigid-body contact dynamics simulated using a velocity-level contact model formulated as a linear complementarity problem~\cite{anitescu1997formulating}. Our hybrid simulator uses a point-based nonlinear-spring contact model where the normal force is solved analytically through the Hunt-Crossley model~\cite{hunt1975coefficient} and the friction force is learned by a neural network that receives the relative velocities, contact normal force and penetration depth as input. Before optimizing the analytical and neural model parameters, the trajectories of a cube thrown horizontally on the ground differ dramatically. After system identification using PBH applied on \autoref{eq:sim2rel_loss} given trajectories of positions and velocities from the target system, the gap is significantly reduced (\autoref{fig:results} left).

In the next experiment, we apply our approach to a real-world dynamical system. Given joint position trajectories from the double-pendulum dataset provided by Asseman et al.~\cite{asseman2018learning}, we optimize inertia, masses, and link lengths of our simulated model and achieve a minimal sim2real gap (\autoref{fig:results} right).

\section{Conclusion}
\label{sec:conclusion}

We have demonstrated a simulation architecture that allows us to insert neural networks at any place in a differentiable physics engine to augment analytical models with the ability to learn dynamical effects from data. In our preliminary experiments, efficient gradient-based optimizers quickly converge to simulations that closely follow the observed trajectories from the target systems, while poor local minima are overcome through a random search strategy.

Future research is directed towards more automated ways to identify where such extra degrees of freedom are needed to close the sim2real gap given a few trajectories from the real system. Our loss function in \autoref{eq:sim2rel_loss} regularizes the contributions of the neural networks to the overall system dynamics. Nonetheless, this approach does not prevent violating basic laws of physics, such as energy and momentum preservation. Hamiltonian~\cite{greydanus2019hamiltonian} and (Deep) Lagrangian neural networks~\cite{lutter2019delan,cranmer2020lagrangian} explicitly constrain the solution space to remain consistent with such principles but need to be further investigated in the context of residual models in hybrid simulators.

\bibliographystyle{plainnat}

redpajama_set_name: RedPajamaArXiv


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Look for the Gold Onion Dome Tower to Feel Good on the Mag Mile
January 31, 2020 Yvonne Pulido 0
Picture a bottle of fancy Prosecco on ice, with an elegant white tablecloth draped over, patiently awaiting your arrival to the 28th floor corner King Luxury Suite at Chicago's Intercontinental Hotel. Cookies and milk preferred? […]
THOMAS J CHURCHILL INTERVIEW By Edmund Barker
January 31, 2020 Jimmy Star 0
As an avid director, writer, and actor going back to his youth in New York, Thomas J. Churchill has a lot of experience in the indie and b-movie worlds that makes for great stories. I […]
Acqualina Resort and Spa – A Mother, Daughter adventure
January 30, 2020 Splash Magazines Contributor 0
By Rollie Hochstein My last mother-daughter spa escapade took place decades ago at a funky spa in southwest California. It was a fairly spartan establishment and my clearest memory (daughter Kate's, too) is the mud […]
Until the Flood Review – On being Black in a White Society
January 30, 2020 Elaine Mura 0
Written and performed by Dael Orlandersmith, UNTIL THE FLOOD was commissioned by the Repertory Theatre of St. Louis to explore a community in turmoil following the shooting of Michael Brown, an unarmed black teenager, by […]
Seafood when you dock at Harbor
Dinner is a meal that one especially looks forward to amid the cold pinch of winter. A great way to warm and nourish yourself is by stepping into 1312 S. Wabash, the South Loop's latest […]
Health, Fitness & Sports
Develop a Healthier, Stronger, Painfree Body
By Vince Hall This is the first of a series of articles designed to help you reduce pain, and work towards a healthier lifestyle and a "happier" body. No matter if you're in good shape […]
Impact the Palm Beaches Annual Awards Event -$159,000 Awarded to Three Local Non-Profits
January 30, 2020 Ellen Eichelbaum 0
I was honored to be covering The Impact the Palm Beaches hosted the 5th Annual Impact Awards Celebration on January 21, 2020, at Oxbridge Academy in West Palm Beach. The women who are involved in […]
"Raise The Spirit" preview- The Ethnic Heritage Ensemble's 47th annual tour for Black History Month 2020
January 30, 2020 Debra Davy 0
Fresh from a fantastically successful year touring the world promoting Be Known: Ancient Future Music, their new subtly evocative Afro-centric jazz double vinyl LP, which launched Spiritmuse Records, Kahil El'Zabar, vocals and percussion, Corey Wilkes, trumpet, […]
SMITH CENTER'S 2020-2021 BROADWAY LAS VEGAS® SERIES – HAS BROADWAY'S BIGGEST SHOWS AND LV PREMIERES
January 29, 2020 Dianne Davis 0
LAS VEGAS (Jan. 27, 2020) – The Smith Center for the Performing Arts' Broadway Las Vegas® Series, returns with an impressive 2020-2021 season featuring nine hit Broadway stage productions direct from New York with a collective […]
Guerrero conducts the NFM Wroclaw Philharmonic review- Piotr Anderszewski at Symphony Center, Chicago
On January 25, 2020, 6- time Grammy award winning conductor Giancarlo Guerrero, Music Director of the NFM Wroclaw Philharmonic, led the orchestra and Guest Pianist Piotr Anderszewski in a concert including works of composers Lutoslawski, […]
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