extfieldsofstudy: Economics Medicine

s2fieldsofstudy: Business Medicine

text:
Moving Medicine, Moving Minds: Helping Developing Countries Overcome Barriers to Outsourcing Health Commodity Distribution to Boost Supply Chain Performance and Strengthen Health Systems

Senegal and other developing countries are improving access to health commodities by outsourcing supply chain logistics to private providers. To achieve broader, lasting reform, we must support further adoption of the outsourced model; assist country-led cost-benefit analyses; and help governments build capacity to manage contracts and overcome other barriers.

INTRODUCTION
U ntil recently, women in Senegal who went to their local public health clinics seeking a means to prevent pregnancy had about a 3 or 4 in 5 chance of leaving empty-handed. 1 Implants, pills, injectables, and other contraceptives, while promoted as part of Senegal's commitment to improving maternal health and access to family planning, were routinely out of stock. The problem, all too common in developing nations, was improper supply chain management, specifically inventory management and delivery. To address this, the government of Senegal embarked on a major overhaul of its supply chain for 9 different contraceptives (with 2 more added later). Within 6 months, stock-outs ceased almost entirely. 1,2 Key in the success of Senegal's reform was the government's strong commitment to, and effective implementation of, hiring private third-party logistics providers (3PLs) to manage orders and handle deliveries from district warehouses to local health facilities, with clear benefits for service levels and costs. One analysis compared cost and service through the use of private operators versus those of government employees performing the same activity in a different region of the country. The analysis found that outsourcing decreased the proportion of facilities experiencing stock-outs from over 80% to less than 2% 1 while reducing distribution costs by 36% annually. 3 These gains were achieved during a 3-year program supported by MSD for Mothers (known as Merck for Mothers in the United States and Canada), The Bill & Melinda Gates Foundation, IntraHealth International, and other partners. During the program, other components developed by the private sector were implemented, including an innovative inventory management system and new methods of data tracking to support mobile warehousing. These made stock replenishment more responsive to real consumption. Contracted workers are able to accurately track and verify consumption and stock levels and plan and customize shipments; regular data uploads allow them to quickly address potential issues.
Qualitative analysis and cost comparisons between regions being served by 3PLs and the one region that was not served by 3PLs helped garner support within the government for the outsourced model. In summer 2016, the new system began transitioning from donor-supported partners to government control under Senegal's National Supply Pharmacy (PNA), a process that is expected to take several months. At the launch of the handover process in August, the Director of the PNA pledged to continue contracting with private operators for last-mile deliveries to all 1,400 of the country's service delivery points, and to expand the system to cover approximately 100 products by the end of 2017. Senegal's Minister of Health and Social Action has endorsed the outsourced model as a way to help ensure access to essential medicines and health commodities for all citizens. This political support is both encouraging and necessary, as long-term success will depend on the government's ability to institutionalize the approach.
A handful of other developing countries are also pursuing outsourcing and reaping the benefits. In the Western Cape Province of South Africa, for example, the storage, handling, and transportation of vaccines has markedly improved in the hands of a 3PL while costs have also been lowered. 4 Kenya outsources the transport of medical supplies to all its health care facilities, having determined that managing a fleet of trucks was neither a core competency of government nor an effective use of government resources. 5 In Nigeria, direct deliveries from an outsourced provider have increased the availability of vaccines in Kano and Lagos, 6 and, despite constraints from the economic downturn and weaknesses in management capacity, the direct delivery model is gradually being expanded nationally. In Mozambique and Zimbabwe, direct deliveries of a range of products have increased stock availability, enhancing system performance. 7,8 In other places, however, such as Togo, similar programs have not been as successful. The success of direct-delivery programs managed by the private sector ultimately depends on strong government commitment; clear roles and accountability mechanisms; a robust technical design of the processes and key performance indicators to be measured; and effective multistakeholder collaboration.
We urge other developing nations-in Africa and elsewhere where public-sector supply chains have been underperforming for years-to look to these countries' experiences as examples of what can be achieved and reminders of the issues that will need to be addressed (Table).

THE ADVANTAGES
When deciding whether to outsource, there are many benefits to consider. For example: Outsourcing improves performance through competition. It brings market forces into play, with competitive bidding and performancebased incentives. To stay competitive, 3PLs invest to acquire the technical expertise and capital assets they need to provide top service while keeping prices in line. Top performers earn contracts. If they fail to perform, another company gets the job. Poor performance by public-sector personnel is more difficult to rectify. Private operators are highly incentivized to comply with the strict storage requirements governing health commodities. Those who fail to do so risk termination of their contracts. (For these incentives to work, of course, governments must be willing to hold those service providers accountable.) Private 3PLs are better-equipped to manage growth. Government agencies typically lack the flexibility and capacity to scale quickly to address seasonal issues or outbreaks, due to rigid budgets and bureaucratic hiring processes. 3PLs typically add stronger information and data management systems, enabling greater stock management and resource efficiency. (Data, and data visibility, are central to supply chain performance.) For all these reasons and more, outsourcing is standard practice across Canada, Europe, and the United States, and in the rest of the developed world. In fact, no country in the Organisation for Economic Co-operation and Development (OECD) has a government-run public health supply chain. [10][11][12] The U.S. Centers for Disease Control, for example, has achieved significant cost efficiencies outsourcing storage and distribution for its multibillion dollar Vaccines for Children program 13 ; the UK National Health Service, which outsources procurement, storage, and distribution to DHL, has projected a savings of a billion pounds over 10 years. 14,15 Developing countries stand to benefit from outsourcing in two other critical ways. First, with private contractors handling deliveries and other on-the-ground logistics, doctors, nurses, and other clinical staff can concentrate on their primary responsibility and core competency: patient care. In a government-run system, it is the medical personnel, already in short supply across the developing world, who are often saddled with part-time supply chain duty, filling out inventory forms, traveling to storage sheds to collect stock, and performing other tasks for which they were not originally trained. When outsourced, skilled 3PL workers make the deliveries and perform the inventory control. This task shifting is a key benefit of Senegal's outsourced distribution model. It has allowed government employees to be redeployed to new clinical support and management positions, not downsized, as is often feared.
Second, government spending through outsourcing stimulates the local economy by creating business opportunities for local entrepreneurs that in turn create new private-sector jobs. In Senegal, local operator Cabit SA has doubled its staff from 30 to 60 since being contracted by IntraHealth International to handle logistics. In Malawi, contraceptives and some essential medicines (including antimalarial drugs) are distributed by Cargo Management Logistics (CML), a local private company that has grown from 46 to 112 employees in the 4 years since taking on this work. In Nigeria, Imperial Health Sciences manages warehousing services and deliveries by 7 locally owned and financed transport companies, which together employ more than 270 people to deliver products to 5,000 points of care.

THE CHALLENGES
Given all the upside, why has outsourcing failed to catch on in the developing world? Here, we provide a few explanations. First, outsourcing requires a sharp break with an old tradition of moving medicine through government-owned centralized stores. This colonial practice was later reinforced when Ghana gained independence and tried to emulate the supply chain model used in the former Soviet Union. The Soviets owned and operated the medicine supply chain, so Ghana Evaluate what lies within government's core competency, and what lies outside of it. Through oversight and enforcement of strict service-level agreements, governments can maintain control over their supply chains even while outsourcing the logistics; government still owns and manages the process, even when non-government drives the trucks.
Built-in performance incentives: Logistics operators are motivated to provide effective, efficient service and prevent stock-outs in order to win and keep their contracts.
There is insufficient capacity and expertise within governments to write and effectively manage contracts with private operators.
Assist governments with building effective contract management and enforcement teams.
Medical staff at service delivery points are no longer responsible for restocking inventory and can focus on patient care; new jobs are created in the local private sector as local companies hire more employees and otherwise invest in their own growth to secure government contracts.
Outsourcing the logistics of health commodity distribution could threaten to eliminate some public-sector jobs.
Governments may need help restructuring their human resources and retraining and reassigning employees for oversight and supervisory roles; local private operators may need training and other support.
In a government-run distribution system, employee working hours and staffing levels are fixed; private operators can be more flexible, so government pays only for what it needs and uses.
In some markets, it can be difficult to find private-sector operators trained and equipped to use state-of-the-art approaches to inventory management and to comply with strict requirements regarding storage and transport of medicines.
Private-sector donors or businesses, acting as fourth-party providers, can assist in the professional development of local private-sector operators.
Contracting with multiple operators can help spread risk, so that the failure of one is far less likely to bring a whole system down.
Concerns exist about long-term financing and sustainability of the new health distribution system given the temporary nature of donor support.
Private-sector expertise can help with the necessary costing analysis, but top-level, in-country leadership must take ownership over the process-and the solutions.
a Outsourcing in Senegal reduced distribution costs by an estimated 36%, 3 and outsourcing the distribution of vaccines in South Africa yielded significant savings, from 28% of the vaccine cost to 6%. 9 Outsourcing stimulates the local economy by creating business opportunities for local entrepreneurs. and many other countries in Africa did the same. However, this model has long proved inefficient and fragile, hobbled by weak performance incentives and the inability to flex capacity as needed. By the 1990s, the model was already struggling across Africa and it buckled when the HIV crisis hit. Subsequent efforts, with international assistance, to sustain this model have done little to alter the fundamental structure, which continues to prove incapable of handling the ever-widening scale and diversity of products required to meet patient needs. Second, many developing nations lack the mechanisms and capacities for contract management and oversight. And it can be difficult to find local private operators capable of handling health product distribution. In some countries, private logistics operators may only serve urban areas. For example, Beale et al. 16 and VillageReach 17 highlight the lack of transport providers in rural Mozambique. Private companies require longterm contracts to invest in transport capacity in an underserved region where they do not currently serve a market. Yet governments are hesitant to make long-term contracts as for many this is not yet a proven model. For transporters, especially smaller local players, the timeliness of government payment is also critical for their cash flow.
Third, concerns that outsourcing threatens public health sector jobs can dampen political support. Nobody wants the prospect of laying people off, particularly in countries where the public sector is the primary source of stable employment.
In addition, while outsourcing can reduce product diversion and pilferage, a robust, transparent, and rigid tender process for the outsourced contract award is a prerequisite for its success.
Finally, there is the question of sustainability. Donor-funded programs are often the way that outsourcing is introduced and tested in a country. Yet it is often the pattern that such efforts prove initially successful, only to revert to insourcing when the program transitions back to government. Kenya, for example, reverted back to insourcing some of its distribution activities when an outsourcing project supported by the U.S. Agency for International Development (USAID) ended. Concerns about long-term financing-and the temporary nature of donor support-have made many country leaders reluctant to take the necessary steps toward change, even as they readily acknowledge a pressing need for it. The benefits of outsourcing and direct delivery are based on the combination of technical design (who manages inventory control, information flow), source of financing (donor financed vs. domestic financing), and commitment from political leaders or heads of public agencies. The benefits can start declining when one of these ingredients is missing or becomes diluted over time.

THE WAY FORWARD
To overcome these barriers, we need to support country leaders as they determine which segments of their supply chains are best suited for outsourcing, and as they seek to identify what truly lies within the core competency of government Employees of Cabit, a 3PL hired to handle last-mile distribution of contraceptives and other health commodities, record consumption and delivery data in a stock room of a health center in the Fatick region of Senegal. and what lies outside it. They will need support to adequately assess risks, costs, and potential savings, as well as their own abilities to manage contracts with outsourced partners. And they may need help restructuring internal human resources for new supervisory roles within the new system. The 2015 Gavi study, ''Outsourcing the Distribution Component of Vaccine and Medicine Supply Chains,'' carried out by Transaid,18 offers a useful framework for these strategic discussions.
For those governments considering a move toward outsourcing their supply chains and to all supporting partners and stakeholders-public and private-we recommend the following: Conduct an in-depth, cost-risk-benefit analysis of the existing government-run, insourced distribution system. Have an honest discussion about what changes are feasible and who is going to pay for it. The private sector knows how to do the kind of granular costing analysis that is required, and does it well.
Top-level country leadership should drive the process from the beginning, so that government-including the finance ministry-takes ownership of both the analysis and the solutions. Take full account of the many hidden costs of a government-run distribution system, such as asset depreciation and staff time spent away from their clinic post. If not exposed, these hidden costs can make an outsourced model, in which costs are more explicit, seem expensive by comparison. Spending more may make sense if it means dramatically improved product availability on shelves. Make clear the return on investment.
Procure 3PL services through a competitive process to keep costs in line. Consider having a commercial or NGO partner serve as a fourth-party provider (4PL) to manage subcontracts with several 3PLs-which Mozambique, Nigeria, Senegal, and Zimbabwe all have done. A 4PL adds value by streamlining the government's role in the nitty-gritty logistics and in performance management, by creating a single point of engagement. The 4PL can find, train, and manage all local transport partners, and it has the incentive to make sure they do well. (In Senegal, IntraHealth International, acting as a 4PL, provided training for Cabit SA and other 3PL employees on the new inventory management techniques adopted as part of Senegal's newly revamped distribution system.) Engaging a 4PL represents an additional cost layer, however, and can be a disincentive to outsourcing unless the benefits are clearly understood. Build in a transition plan from the start to ensure sustainability after donors pull out. The main challenges facing Senegal during its transition will be managing the higher costs and greater data collection and demand planning requirements posed by a tenfold increase in the number of 3PL-distributed products. Explore how existing government staff might be retrained and reassigned to new roles in contract management and oversight. In an outsourced system, government is still in control of the public supply chain, so it is government that must enforce service-level agreements and ensure that performance targets are achieved. Look at pharmacists and others who have been pulled away from their field to work the supply chain and allow them instead to return to what they originally studied. Develop sufficient government capacity for contract management and other mechanisms for effective private-sector engagement. Rigorous government oversight is essential to secure compliance, prevent corruption, and ensure that drugs are not misused or mishandled. Contracts will also need to include the proper incentives to ensure that 3PLs distribute to rural and remote areas, not just the major towns and other densely populated regions. (USAID's experience through its DELIVER Project highlights the importance of building a strong contract management team, 19 and VillageReach's experience in Mozambique highlights similar challenges. 8 ) Key performance indicators-the ability of outsourced partners to manage costs, quality of service, responsiveness, etc.-must be carefully designed and monitored. Strong contract language by itself is not enough; overseers must be willing and able to enforce the terms and conditions. Select individuals with prior private-sector logistics and supply chain experience to serve as top-level supply chain managers. Those with a commercial background are more likely to make the bold (and sometimes politically unpopular) decisions necessary to implement Top-level country leadership should drive the outsourcing process from the beginning.
change. Progress in Kenya has been widely attributed to the fact that an executive with rich private-sector experience was brought in to run the Kenya Medical Supplies Authority (KEMSA). Under his leadership, KEMSA has become less bureaucratic, more independent, and more competitive and a good model for other countries looking to outsource and otherwise streamline their operations. Engage the public in the debate over supply chain reform, by communicating what's at stake for consumers-in other words, how a well-functioning supply chain helps protect, improve, and save lives. One way to do this is to present performance metrics in terms that are relevant and relatable to patients. Are the medicines and other supplies available when they need them? Are they affordable and accessible? How far do patients have to travel to get to them? Activists and civil society can play an important catalytic role by shining a spotlight on poor performance and advocating for more reliable access. Sweden, the last industrialized nation to embrace private sector-run medicines distribution (in 2009), tapped a bipartisan, independent agency to monitor and review the successes and deficiencies resulting from the privatization. By highlighting issues important to the general public (not just supply chain experts), the agency allowed government to build public confidence in the project. 10 If we can similarly generate public interest in supply chain issues in developing countries-and engage civic groups and other community organizations, which can often sway the course of public health policies and programs and bring about greater transparency-we can galvanize public support for the solutions.
Global stakeholders should build a stronger evidence base for where, when, and how outsourcing works in a long-term, sustainable way in developing country health systems. This will create a global public good in terms of knowledge of what any country starting to consider outsourcing should watch out for, and how to remedy failures and create the right prerequisites for success. Before embarking on such projects, global agencies must also pay close attention to the complex political economy surrounding such projects that is present in many low-and middleincome countries. They must develop a clear path to more effectively communicate its benefits and risk mitigation approaches and bring on board government stakeholders who will strongly advocate for this.

CONCLUSION
Demands on in-country supply chains will only intensify going forward. The sheer volume of drugs and other products flowing into the public health pipeline increases year after year, as new treatment options become available and governing bodies establish more ambitious health targets. The newly adopted Sustainable Development Goals call for universal access to reproductive health care. The new ''90-90-90'' targets from the Joint United Nations Programme on HIV/ AIDS (UNAIDS)-by 2020, 90% of people living with HIV will know their HIV status, 90% of people diagnosed with HIV will receive sustained antiretroviral therapy, and 90% of people receiving antiretroviral therapy will have viral suppression-will essentially double the number of patients who will require treatment over the next 5 years. The need to ensure continuous access to maternal and child health commodities, as well as the rising prevalence of hypertension, diabetes, and other non-communicable diseases in developing countries, will add further strain. Supply chains will have to be even stronger, more efficient, and more effective to enable governments to meet the needs of their citizens. The recent Ebola outbreak is a stark reminder that supply chains must be agile and responsive-and a reminder of the tragic consequences when they are not.
We believe that to get public health supply chains-and patient access-to where they need to be, private-sector outsourcing needs to be part of the equation. Health ministries can and should learn from the Senegal experience, and from the successful efforts of other countries to outsource parts of their supply chains. We believe that many of the obstacles are surmountable and that in most cases, with the proper conditions and support, outsourcing can improve health commodity availability and help strengthen health systems.
The women of Senegal are already benefitting from their country's supply chain overhaul in family planning. Since the reform, a young wife trying to space her pregnancies to avoid complications, the mother of 6 children who is in no condition to have a seventh, and all the other women who require contraceptives, have been able to depend on the availability of contraceptive products in a way that was unheard of just a few Supply chains will have to be even stronger, more efficient, and more effective in the future to enable governments to meet the needs of their citizens. years ago. This is what a top-performing supply chain can do, and it is what every person, everywhere, deserves.


extfieldsofstudy:
Computer Science
Medicine

text:
Estimation of Cyclic Shift with Delayed Correlation and Matched Filtering in Time Domain Cyclic-SLM for PAPR Reduction

Time domain cyclic-selective mapping (TDC-SLM) reduces the peak-to-average power ratio (PAPR) in OFDM systems while the amounts of cyclic shifts are required to recover the transmitted signal in a receiver. One of the critical issues of the SLM scheme is sending the side information (SI) which reduces the throughputs in wireless OFDM systems. The proposed scheme implements delayed correlation and matched filtering (DC-MF) to estimate the amounts of the cyclic shifts in the receiver. In the proposed scheme, the DC-MF is placed after the frequency domain equalization (FDE) to improve the accuracy of cyclic shift estimation. The accuracy rate of the propose scheme reaches 100% at E b/N 0 = 5 dB and the bit error rate (BER) improves by 0.2 dB as compared with the conventional TDC-SLM. The BER performance of the proposed scheme is also better than that of the conventional TDC-SLM even though a nonlinear high power amplifier is assumed.

Introduction
Orthogonal frequency division multiplexing (OFDM) is multicarrier modulation which provides reliable high speed data rate because of its high spectral efficiency and its robustness against multipath fading channel. One of the significant problems of the OFDM signal is its high peakto-average power ratio (PAPR) that requires wide range linearity in a power amplifier (PA). The high PAPR may drive a power amplifier into the saturation region, create interference among subcarriers, and corrupt the spectrum of the signal [1][2][3]. Some schemes for reducing PAPR have been available, for example, coding, filtering and clipping, and phase manipulation (selective mapping and partial transmit sequences).
Selective mapping (SLM) is one of the popular PAPR reduction schemes without signal distortion. SLM is a probabilistic scheme where signal candidates (SCs) are generated by multiplying the original signal sequence and the phase sequence. The SC with the lowest PAPR is chosen for transmission. In SLM, side information (SI) is needed at a receiver side to recover the transmitted signal. The SI is usually transmitted as a set of bits for every OFDM symbol and channel coding is required to protect it from a harsh channel. It involves the reduction of throughputs in wireless OFDM systems. Moreover, SLM has large computational complexity because it requires several inverse discrete Fourier transform (IDFT) operations and it makes the restrictions in implementation. A lower-complexity SLM scheme has also been proposed to solve this problem [4][5][6][7][8][9][10][11][12][13][14][15].
Many schemes have been proposed to exclude the SI [9][10][11][12][13][14][15][16]. The scheme in [9] makes the difference between the average energies of the extended and nonextended symbols to recover the SI at the receiver. As a consequence, higher order modulation symbols would influence the accuracy of SI detection. The scheme in [10] realizes semiblind SI detection in the SLM. However, this scheme requires embedding the SI in transmit symbols. In the scheme presented in [11], time domain cyclic-SLM with delayed correlation (DC) is applied to reduce a PAPR and to estimate the amount of a cyclic shift at the receiver without SI transmission. Nevertheless, there is a tradeoff between the amount of PAPR reduction and the BER. The method in [12] has been proposed to further reduce the PAPR of the abovementioned scheme. It uses matched filtering (MF) with a Barker sequence to estimate the amounts of cyclic shifts. One of the causes of the estimation error is multipath components. These components mislead the outputs of the DC-MF.
In this paper, time domain cyclic-SLM (TDC-SLM) without SI transmission is proposed. The proposed time domain cyclic-SLM (TDC-SLM) places the DC-MF after frequency domain equalization (FDE) to remove multipath components in a received signal. At a transmitter side, a transmit signal is generated by the summation of an original signal and signals with cyclic shifts. At a receiver side the amounts of the cyclic shifts are detected by using the DC-MF. In this proposed scheme, intervals between the cyclic shifts are designed so that the receiver can distinguish the cyclic shifts and multipath delays with the use of the MF. However, multipath components still deteriorate the accuracy rate of cyclic shift estimation since they generate additional peaks at the outputs of the DC-MF. By using the proposed scheme, the accuracy rate then improves and the bit error rate (BER) reduces as compared to that of the conventional TDC-SLM and DC-MF in [12].
The rest of this paper is organized as follows. Section 1 contains the introduction. Section 2 explains system models including the OFDM symbol structure, time domain cyclic-selective mapping, channel estimation and frequency domain equalization, and the proposed cyclic shift estimation scheme. In Section 3 the performance results of the proposed scheme are presented and finally Section 4 concludes this paper.

System Model
where is the time index, [ ] is the data symbol on the th subcarrier, denotes the subcarrier index, and is the number of the subcarriers. The OFDM signal can also be defined as a vector In order to mitigate the intersymbol interference, a guard interval (GI) is needed. The GI can be obtained by copying the last part of the OFDM signal and adding it to the beginning of the signal.
where GI is the length of the GI.  TDC-SLM scheme is shown in Figure 1. The cyclically shifted signal in the TDC-SLM is given as

Time Domain
where [ ] is the OFDM signal in the time domain at the time index of , GI is the GI length, [ , Δ ] is the SC that is generated by cyclically shifting the OFDM signal by Δ , Δ is the amount of the cyclic shift for the th SC, and Δ ∈ { }, where is an integer [11,12]. The resolution of the cyclic shifts, , has to be large enough for accurate estimation of the cyclic shifts in a receiver. The transmitter combines the SCs to the original signal in the time domain as follows: where [ ] is the transmit signal, is the number of branches, is the th coefficient in the phase sequence, and [ ] is the original signal with the GI. The same set of {Δ } is applied over multiple symbols since the corresponding outputs of the DC-MF are averaged to improve the accuracy of cyclic shift estimation. Thus, the set of {Δ } is selected so that the maximum PAPR over the symbols for averaging is minimized. Here, the PAPR is calculated for each OFDM symbol period.

Channel Estimation and Frequency Domain
where [ ] and [ ] are the th transmitted and received preamble signals in the time domain, respectively. At the receiver, the preamble signal on the th subcarrier is demodulated by taking a discrete Fourier transform (DFT) as The estimation of the channel frequency response on the th subcarrier in the frequency domain,̂[ ], is given as where [ ] is the transmitted preamble symbols on the th subcarrier. Because of the TDC-SLM in the time domain, the channel frequency response needs to be modified during the data period. The superposition of the data sequence works like an artificial multipath on the channel response. To calculate the channel frequency response in the data period, the estimated channel response is converted to the impulse response in the delay domain as follows:ĥ wherê * [ ] denotes the conjugate of the channel frequency response that is obtained from (8) and 2 is the variance of the noise estimated in the receiver. The demodulated signal on the th subcarrier is then where [ ] denotes the signal on the th subcarrier at the receiver.

Cyclic Shift Estimation Scheme.
The DC-MF is applied to the signal in the time domain after the MMSE-FDE to estimate the amounts of the cyclic shifts at the receiver.
The received signal in the time domain can be written as where [ ] is the channel frequency response, [ ] is the signal component, and [ ] is the Gaussian noise on the th subcarrier. Furthermore, [ ] is the th received signal, / 0 is the signal-to-noise ratio per sample, , = exp[(2 / ) ]/ √ , is the size of the DFT, and (⋅) * denotes conjugate. The DC-MF process consists of DC and MF as shown in Figure 2. In the transmitter side, the TDC-SLM generates several SCs by applying cyclic shifts to the original signal after the inverse DFT (IDFT) and generates the transmit signal through the summation of the original signal and the SCs. The DC-MF is utilized to estimate the amount of the cyclic shifts since they are required to recover the transmit signal.
Basically, the DC process multiplies the received signal in the time domain with the conjugate of the GI sequence. The largest peak appears when the last part of the OFDM symbol is multiplied with the conjugate of the GI. The output of the DC is put into the MF to estimate the set of the cyclic shifts, {Δ }, by detecting the second largest peak output. The DC-MF processes with 3 branches are shown in Figure 3. The DC is defined as follows: x x

⋅ ∑
where [ ] = * [ − ] and * [ ] and [ ] are the signal and noise components on the th subcarrier output from the delayed branch of the DC, respectively. After the summation, the outputs of the DC are averaged as follows: where is the number of symbols used in the averaging process. The first peak is caused by the GI and is found by maximization as In addition, the DC produces the correlation between the GI sequence and the received signal with the delay of Δ , that is, whereΔ is the candidate for the amount of the cyclic shift on the th branch. Equation (16) can be rewritten aŝ Therefore, the th peak output of the DC is given aŝ The outputs of the DC are then passed to the MF to estimate the amounts of the cyclic shifts. Figure 4 shows the structure of the MF. In order to reduce the number of the combinations of {Δ }, here, the amounts of the cyclic shifts are selected from every samples as {Δ, Δ + , . . . , Δ + ( − 1) }. The structure of the MF has the delay line in which all the delays are set to ( − 1). The output of the MF is expressed as follows: The cyclic shift of the first branch, Δ, is estimated through maximization as where Δ max is the estimated amount of the cyclic shift for the first branch, Δ. The channel impulse response in (9) is shifted by the estimated cyclic shifts and summed together with the original impulse response as follows: The received signal in the frequency domain after channel compensation is given as follows: where the channel response on the th subcarrier in the data period iŝ[ Table 1 shows the simulation parameters of the proposed scheme which are adopted from LTE parameters. The number of data subcarriers is 128 and each subcarrier is modulated with QPSK. The DFT size is 256 and the length of the GI is set to be 64 samples. The number of symbols for averaging is set to 1, 2, 4, or 8, and the range of the cyclic shift (Δ ) is limited from 60 to 124 The block interleaver with a size of 16 × 8 is applied. The number of branches is 3 and a Barker sequence with a length of 3 ( ) is used as the phase sequence. A uniform delay profile with 6 paths is assumed as the channel model in computer simulation. As a nonlinear high power amplifier (HPA) Rapp's solid state power amplifier (SSPA) model with a knee factor of 3 is assumed. The input back-off (IBO) for the HPA is set to 0, 2, and 4 dB.

PAPR Reduction.
The PAPR performance curves are evaluated in terms of complementary cumulative distribution functions (CCDF). The TDC-SLM assumes = 3 branches with the cyclic shift resolution of = 4 and the number of the symbols for averaging is selected from 1, 2, 4, or 8. From Figure 5, it can be seen that, in comparison with the original signal, the amounts of PAPR reduction in the TDC-SLM for 1, 2, 4, or 8 symbols for averaging are 2.8 dB, 2.7 dB, 2.6 dB, and 2.5 dB, respectively, at the CCDF of 10 −4 . When the number of symbols for averaging is 1, each OFDM symbol has different set of the cyclic shifts and the best PAPR reduction is achieved. On the other hand, the smallest amount of PAPR reduction is realized where 8 OFDM symbols have the same set of the cyclic shifts in order to average the corresponding DC outputs. Nevertheless the difference in the amount of the PAPR reduction for 1 and 8 symbols for averaging is only 0.3 dB at a CCDF of 10 −4 .

Accuracy Rate and BER Performance.
The accuracy rate is the ratio of correct estimation in terms of the amounts of the cyclic shifts in the receiver side. The accuracy rate of the cyclic shift estimation is shown in Figure 6. Here, the uniform delay profile channel is assumed. In Figure 6, the accuracy rate of the proposed scheme for 1, 2, 4, or 8 symbols for averaging is around 57.04%, 87.80%, 98.28%, and 100%, respectively, at / 0 = 5 dB. The multipath channel affects the accuracy rate of the cyclic shift estimation. It is observed that the accuracy rates of the proposed scheme with 8 symbols for averaging are the highest as compared to the others. The accuracy rates of the proposed scheme and the conventional TDC-SLM with 8 symbols for averaging reach 100% at / 0 = 5 and / 0 = 7 dB, for 8 symbols for averaging, respectively. The accuracy rate performance is 2 dB better as compared to that of the conventional TDC-SLM scheme.
The accuracy rate affects the BER performance. The BER performance of the proposed scheme and the conventional TDC-SLM scheme with 8 symbols for averaging is presented   in Figure 7 on the uniform delay profile channel. The difference between the BERs with perfect estimation and the proposed scheme with 8 symbols for averaging is 0.6 dB and it is 0.2 dB better than that of the conventional TDC-SLM scheme.
The BER and the accuracy rate with the HPA are also evaluated. Figure 8 presents the comparison of the accuracy rates between the proposed scheme and the conventional TDC-SLM. The number of the symbols for averaging is set to 8. The accuracy rate of the propose scheme reaches 100% when / 0 = 10 dB, 11 dB, and 13 dB for IBO of 4 dB, 2 dB, and 0 dB, respectively. On the other hand, the accuracy rate of the conventional TDC-SLM realizes 100% at / 0 = 11 dB, 12 dB, and 14 dB for IBO of 4 dB, 2 dB, and 0 dB, respectively. It shows that the accuracy rate of the proposed scheme improves when the DC-MF is placed after FDE-MMSE even though the nonlinearity of the HPA is assumed. The accuracy rate performance is 1 dB better as compared to that of the conventional TDC-SLM scheme. The BERs for the different values of the IBO are also evaluated as depicted in Figure 9. In the conventional TDC-SLM, the required / 0 values at a BER of 10 −3 are 13 dB, 13.3 dB, and 13.8 dB, for IBO of 4 dB, 2 dB, and 0 dB, respectively. On the other hand, with the proposed scheme, it is 12.8 dB, 13.1 dB, and 13.3 dB for IBO of 4 dB, 2 dB, and 0 dB, respectively. It is observed that the BER improves by increasing the IBO. The BER differences between the conventional TDC-SLM and the proposed scheme are 0.4 dB, 0.3 dB, and 0.4 dB at a BER of 10 −3 for IBO of 4 dB, 2 dB, and 0 dB, respectively. The proposed scheme is proven to improve the accuracy rate and the BER performance as they approach the values with perfect estimation.

Conclusions
In this paper, the SI detection scheme for the TDC-SLM has been proposed. The DC-MF is implemented after the MMSE detection to remove the effect of the multipath channel. The amount of PAPR reduction with the TDC-SLM is around 2.5 dB as compared with that of the original signal for 8 symbols for averaging when the resolution of the cyclic shift is = 4 samples. The accuracy rate of the proposed scheme reaches 100% at / 0 = 5 dB and the BER difference with 8 symbols for averaging is around 0.6 dB as compared to that with the perfect estimation of the SI. The BER is 0.2 dB better than that of the conventional TDC-SLM scheme. Under the nonlinearity of the HPA, the proposed scheme still improves the BER performance by around 0.4 dB at a BER of 10 −3 for IBO of 4 dB, 2 dB, and 0 dB.


extfieldsofstudy: Business Medicine

text:
An In-Store Experiment on the Effect of Accessibility on Sales of Wholegrain and White Bread in Supermarkets

Even though whole grain foods have various health benefits, consumers have been found not to eat enough of them. Nudging interventions are built on the premise that food purchases and consumption are strongly influenced by the environment in which decisions are made. Little research has been conducted to examine the influence of a small and inexpensive nudging intervention on bread choices in a real-life supermarket context. An in-store experiment was conducted in two six-week periods in two supermarkets to investigate the effects of accessibility on consumers’ purchase of healthier whole grain and other types of bread. In the high accessibility condition, healthier bread was placed in a more convenient location for the shopper on the left side of the shelves where it was encountered first. In the low accessibility condition, it was placed on the right side. There were consistent significant differences in sales between supermarkets, types of bread, day of the week, but not between low and high accessibility. Additional research is needed to better understand the effects of convenience and accessibility on bread choices.

Introduction
The health benefits of whole grain foods are well documented [1][2][3][4]. Nevertheless, in many countries whole grain consumption is low compared to international recommendations [5][6]. Whole grain consumption has been promoted in various ways, such as by emphasizing or improving its affordability, healthiness, availability, taste and appearance [7][8][9][10]. In the last decade, there has been a considerable increase in interest in using insights from behavioural economics and psychology to change behaviour in a healthier direction, because a lot of behaviour is driven by habits and automatic routines. Every day, people are faced with numerous instances where they have to make food-related decisions such as whether they want to eat, what they want to eat, what the rest of the family want to eat, whether the food is healthy and safe, and whether the food is in line with their health goals (Wansink and Sobal [11] mention up to 200 food-related decisions that the average person has to take per day). Giving each of these questions sufficient thought is mentally exhausting, and there is a great temptation to fall back on automated and less healthy behaviours [12]. Moreover, most supermarket purchases are unplanned, i.e., they are based on in-store decisions. Estimates of unplanned purchases vary between studies. For example, Inman et al. estimate that 60.9% of purchases are unplanned [13].
Increasingly, interventions focus on arranging the decision-making contexts in such a way that they engage with consumers' automatic and impulse-driven decision-making system. These so-called nudging interventions adapt the environment in which people make choices to help them make better choices, without appealing to people's reason or forcing certain choices upon them [14][15][16]. The evidence base for nudging as a means to improve the healthiness of food choices is growing. Depending on the specific studies, increases or decreases in sales as a result of nudging may be as large as 28% [17]. So far, nudging studies have targeted especially homes, schools, grocery stores, and restaurants. The essence of the nudging approach is to change environments in such a way that the healthy choice becomes a more convenient, attractive, or normal choice [18]. This paper focuses especially on the convenience component of a nudge approach by adapting the shelf location of healthier and less healthy breads. Locating healthy foods at a prominent or eye-level place and the unhealthy options further away is one of the most frequently mentioned examples when nudges are defined and illustrated (see for example [14,[19][20]).
Convenience is the result of the ease, time, and comfort involved in obtaining a food and can be achieved in many ways. Small convenience changes in the environment, such as changing the distance to healthy or unhealthy foods, placing specific foods near the checkout, or changing the order of food in buffet lines, are typically not consciously noticed by consumers but have demonstrated effects on food choices and can assist in making the healthy choice the convenient choice [17,[21][22]. Research on the way shelves are stocked in grocery stores shows that a product's absolute and relative shelf position strongly influences the choices that consumers make [23]. The more shelf space a type of product occupies or the more prominent the shelf location (e.g. at eye level or end of aisle display), the more items are sold [24].
The present study examines the convenience nudge principle in supermarkets to select healthier whole grain bread. The habit strength of bread purchases is typically high, as people have a repeated pattern of purchase [25]. Although nudging studies in canteen settings have shown effects of more prominent location of healthier foods [26][27], to our knowledge, no study has specifically attempted to nudge consumers' bread purchases in a real-world supermarket setting. The current research extends prior research by exploring consumer purchase responses to a convenience nudge to encourage whole grain bread purchases in two supermarkets over an extended period of time. Healthier bread choices were made more convenient by altering the horizontal shelf position and therefore the accessibility (healthier bread is encountered either first or last during visits to the bread section). We hypothesize that the purchase of a certain category of bread is higher when it is encountered first, as it is more visible and prominent than when it is encountered last.

Methods Setting
Data were based on sales of every type of fresh bread sold in two supermarkets ("supermarket A" and "supermarket B") in the same chain located in Veenendaal, the Netherlands. Both supermarkets shared a similar store layout. The fresh bread department of both stores was located next to the entrance, and all customers passed this department before they entered the rest of the store. Five clusters of fresh breads were identified, labelled for this study as whole grain (9 types), dark wheat (4), wheat (6), light wheat (4), and white (8) because, in Dutch supermarkets, bread is identified by colour rather than by degree of refinement of the wheat.
These bread clusters were organized on shelves on the left side of one aisle that customers entered from the left and exited from the right (see Fig 1). An additional cluster of banquet/ bake-off breads (84 types) was situated on the far left and a cluster of specialty bread (26 types) on the far right of the aisle. Shelf height ranged from approximately 30 cm to 150 cm, shelf width was eight and nine metres in supermarket A and B, respectively.

Experimental design and procedures
In the "healthier bread first" condition, whole grain bread was placed at the entrance of the aisle (next to the banquet/bake-offs), followed by dark wheat bread, wheat bread, light wheat bread, and white bread. In the "healthier bread last" condition, the order was reversed, with whole grain bread placed at the exit of the aisle, just before the specialty bread (Fig 2).
The effect of horizontal shelf location was investigated over two periods. During period 1 (week 43-49, 2013), bread was presented in the "healthier bread first" condition in one supermarket (location B) and in the "healthier bread last" condition in the other supermarket (location A). During period 2 (week 5-9, 2014), this order was reversed. Ideally, the second period should have been as long as the first period, but the second period was shortened due to the fact that the original shelf placement needed to be restored in view of upcoming holiday sales. The supermarket staff refilled shelves during the day. Researchers visited both supermarkets daily to verify the bread placements over the shelves.

Measurement and statistical analysis
The dependent variable was the total number of units of bread sold per day from each of the five bread categories. Since breads were sold as wholes and halves, all sales were recalculated to one whole unit, e.g. one half bread was recorded as 0.5 unit of bread. Day of the week and number were recorded per location, as well as bread promotions. Both supermarkets offered the same bread promotions at the same time, but promotions varied per week in both experimental periods.
The supermarkets differed in the absolute number of bread units sold. To compensate for these differences in absolute sales, and to correct for weekly bread promotions, ratios between the bread sales of both supermarkets were calculated based on average weekly sales during both periods. Thus, for each bread type, the ratio "Sales in Supermarket A":"Sales in Supermarket B" was calculated for each week. An effect of accessibility on whole grain bread sales should result in relatively more whole grain sales in supermarket B during period 1, where it was more accessible, and relatively fewer sales during period 2 compared to supermarket A. As it was expected that a carry-over effect might occur that affected wheat bread sales, in the analysis wheat bread was divided into three categories based on colour.

Bread sales: General
Absolute numbers of sold units of breads were used to verify statistical differences between bread type, day of the week, and supermarkets. Bread sales in supermarket B significantly exceeded bread sales in supermarket A on average by 68% during both periods. Despite differences in absolute number of bread sales, both supermarkets showed similar effects of day of the week and type of bread (Table 1)

Bread sales: Effect of accessibility
To investigate an effect of accessibility of whole grain bread across both supermarkets, a 5x2 ANOVA with type of bread (whole grain, dark wheat, wheat, light wheat, white) and condition ("healthier bread first", "healthier bread last") as between-subject factors on average week sales ratio was performed. A main effect was found on the average sales ratio between supermarkets for bread type (F (4, 55) = 13.0, p < .001, eta 2 = .487), but not for time period (F (1, 55) = 1.90, p = .174, eta 2 = .033), nor for the interaction between type of bread and time period (F (4, 55) = 1.95, p = .115, eta 2 = .124). Thus, the sales of bread type differed in the two supermarkets. However, no effects of condition, or an interaction between condition and type of bread, were found. Hence, accessibility did not affect sales (Fig 3).

Discussion
The unplanned character of most in-store consumer decisions coupled with the automatic and habit-driven nature of many consumer decisions offer opportunities to gently direct-or nudge-consumers towards healthier foods. In the present study, the effect of a convenient shelf space location on the sales of whole grain and white bread was examined in two supermarkets by varying their accessibility. In the accessible, healthier bread first condition, whole grain bread was placed in a more convenient position on the left side of the shelves in the bread section (Fig 2). In this condition, customers encountered the healthier bread first. This order was reversed in the less accessible, healthier bread last condition.
Overall, the results showed no effects of our manipulation on sales of the different bread types. That is, sales of whole grain bread were not affected by placement in a more or less convenient location. A number of reasons might explain this lack of effect. First of all, it can always be argued that longer intervention periods and more test supermarkets could have produced different results. However, the intervals used and the low number of test supermarkets did show consistent and significant effects of variables such as the day of the week, specific weeks, and promotions on bread sales (not shown). In view of these significant effects, we believe that Sales of whole grain bread were significantly higher (32.5% of total bread sales) than sales of dark wheat bread (17.9%), wheat bread (25.0%), light wheat bread (9.7%), and white bread (14.9%) ( a lack of significant convenience effect demonstrates that it is either absent or very small and therefore irrelevant. Second, consumer bread preferences and purchase habits are strong, and this may lead to a less 'nudgeable' product. Nudging requires the right amount of strength to influence decisionmaking processes. The fact that most consumers buy the same type of bread even when its location in the store changes suggests that consumers have strong bread preferences, at least with regard to white and whole grain bread; a typical consumer of white bread may not select whole grain bread instead just because whole grain bread is encountered first, and vice versa. This effect may be especially strong for white and whole grain bread, which may appeal to very different consumer segments [28][29]. Other types of bread such as whole grain and wheat bread may be more interchangeable for consumers [30]. Consumers often believe that the darker the bread, the healthier it is. In retrospect, varying the accessibility of whole grain and wheat bread could have produced more positive effects in this study.
Bread is also a product that is typically purchased on a regular basis, sometimes even daily. This, plus the fact that bread does not trigger purchasing behaviour like products such as beer or fatty food, means that the purchase of bread is most often habitual and planned [13]. The habitual and planned nature of bread purchases could refer to either the location of specific breads or the bread type itself. If bread purchases are driven by location, switching breads to different locations should lead to a shift in sales from one type of bread to another. The fact that this does not happen in this study suggests that habit refers to the type of bread that is purchased and that customers will look for that preferred bread in the event of relocation. The preferred bread category may be broader than one specific type of bread and may include for example whole grain as well as wheat bread; this could be the subject of further studies.
Finally, the effectiveness of nudges may be very context-specific. A question that arises is whether the convenience and the prominence of the bread were really varied. In other studies, the convenience of product selection is varied for example by placing the products closer to or further away from the shopper [17], or by placing them at the beginning or at the end of a line buffet [22]. In the former case, it takes more effort to select the product that is further away. In the latter case, the assumption is that it is more convenient to select the product at the beginning of the line rather than risk the possibility of encountering no more attractive alternatives in the rest of the line and having to go back (often against the traffic). We had speculated that our supermarket intervention would resemble the line buffet intervention. However, there are some critical differences. Going against the traffic may be much more problematic with a line buffet than in our supermarket situation because of the amount of traffic and the available space to manoeuvre. As Fig 1 clearly illustrates, neither factor is typically really relevant in the test supermarket. Consequently, (perceived) accessibility may have been similar for the breads placed at the entrance and at the exit of the bread department.
In summary, the results of the study demonstrate no effect on sales of placement of bread near the entrance or near the exit of the bread department of supermarkets. Future studies may include other product categories and other types of product placements in supermarkets to explore whether the lack of effect in this study is related to the bread product category and/or to the good accessibility of the products within this category.


extfieldsofstudy:
Engineering
Computer Science
Medicine

text:
Experimental dataset for optimising the freight rail operations

The freight rail systems have an essential role to play in transporting the commodities between the delivery and collection points at different locations such as farms, factories and mills. The fright transport system uses a daily schedule of train runs to meet the needs of both the harvesters and the mills (An Integrated Approach to Optimise Cane Rail Operations (M. Masoud, E. Kozan, G. Kent, Liu, Shi Qiang, 2016b) [1]). Producing an efficient daily schedule to optimise the rail operations requires integration of the main elements of harvesting, transporting and milling in the value chain of the Australian agriculture industry. The data utilised in this research involve four main tables: sidings, harvesters, sectional rail network and trains. The utilised data were collected from Australian sugar mills as a real application. Operations Research techniques such as metaheuristic and constraint programming are used to produce the optimised solutions in an analytical way.

Specifications
A near optimal scheduler for trains was produced using a real sector of Australian rail network. Data source location Queensland University of Technology, Brisbane, Australia Data accessibility Data is within this article

Value of Data
The main aim of the presented data is to develop mathematical models of the freight rail systems and help in producing effective solutions in a reasonable CPU time.
In this research, minimising the makespan is proposed as a main criterion to optimise the freight rail systems using the introduced data. The results in this research can be used to compare the performance of the proposed mathematical methods in optimising complex systems such as rail systems in many prospective studies.
The data of the produced schedules of the train runs can be used for many different types of the freight systems such as the sugarcane or coal rail systems [5]. The data describe the daily trips of each train to deliver the empty bins at different locations called sidings and collect the full bins from these sidings for delivery to the mills or the factories.

Data
Based on the feedback from our industry partners, the data utilised in this research are created in four main tables: Sidings (Table 1), Trains (Table 2), Harvesters (Table 3) and Rail Network (Table 4). In addition, three figures are presented to show the main steps of the proposed solutions: Kalamia's mill with the main original map (Fig. 1), the main steps to produce the final solution (Fig. 2), and the daily trips of each train in the system (Fig. 3).

Experimental design, materials and methods
A case study was examined to validate the constraint programming models and metaheuristic techniques. Fig. 1 shows a sector of the transport system of Townsville's mill in Queensland, Australia. Many train runs are generated where each run start at one mill and finishes at the same mill after visiting many different siding locations. The number of trains was selected to implement different runs requiring a fewer number of trains. Kalamia's mill has 58 sidings located in 9 segments but not all of them work on the same day. Approximately 14 trains can be used to construct the train trips that deliver empty bins to sidings at farms and collect full bins from farms top sidings. The data table of sectional rail network was constructed to describe the rail section length between different sidings. Constraint programming (CP) is one of solution techniques to find a near optimal scheduler for the sugarcane rail systems. The proposed mathematical model considers the siding and train capacity constraints, daily allotment constraints of each harvester, train passing constraints where each train cannot occupy more than one rail section at a time or two trains can occupy one section at a time. Constraint programming that deals with problems defined within the finite set of possible values of each variable is the main technology used for solving mathematical formulation problems  120  120  22  22  22  22  2  SELKIRK  120  120  22  22  22  22  3  BURDEKIN  120  120  22  22  22  22  4  STRATHALBYN  120  120  22  22  22  22  5  DELTA  120  100  20  18  20  20  6  AIRDMILLAN  100  80  20  18  20  20  7  CHIVERTON  100  72  20  18  20  20  8  KALAMIA  110  82  14  12  14  13.3  9  BOJACK  120  120  30  30  32  30.6  10  CARSTAIRS  110  90  28  22  30  26.6  11  NORTHCOATE  110  90  28  28  28  28  12  JARVISFIELD  120  120  34  34  34  34  13  RITA ISLAND  120  120  34  34  34  34  14  KILRIE  120  120  34  34 34 34  through the search trees. Fig. 2 shows an example of four feasible solutions to clarify the stages of obtaining these solutions using the search tree for the DFS algorithm, where each solution is shown by three subgraphs that start with discovering the nodes of the search tree to find the solution. The search tree uses coloured nodes to express the node types. For example, the red nodes are the failures, the solutions are green, the blue nodes are the explored choice points, white are the nodes  [1][2][3][4]. The use of the Gantt chart has been proven as a useful tool to validate the solutions' applicability and to evaluate the algorithms' performance through the ACTSS Schedule Checker for Kalamia Mill. As shown in Fig. 3, the different numbers of trains are indicated by using different colours to satisfy the specific allotment for each siding during a day. The rail sections have been constructed on the vertical axis while the time of each trip had been shown on the horizontal axis. The red numbers on the graph show the number of delivered empty bins and green numbers show the number of collected full bins at each siding.


Momentum for Independent versus Group Firms

A prior research finds a significant seasonal momentum in the Taiwanese stock market. While intending to explore rationales for the seasonal momentum, this study use a relatively large dataset to verify whether strength of the momentum is different across independent and group firms. Empirical evidence do not report significant differential momentum effect between the two types of firms, inconsistent with prior findings, which reveal more pronounced momentum on independent firms.

Introduction
One feature of Asian firms is domination of group firms, i.e., firms closely associated with other firms in terms of cross holding of shares or common controlling under a person, a family, or a group of related families (Claessens et al., 2000). Chui et al. (2003) examine relation between price momentum and independent/group firms, finding stronger momentum among independent firms than among group firms. In this study, we duplicate their tests in a much larger dataset composed of both listed and delisted Taiwaneses firms.
Basically, there are two competing theories explain why the strength of momentum will be different between independent and group firms. At one hand, the psychological bias theory asserts that group firms' financial statements are more complex and less transparent than those of independent companies owing to the complexity of cross holding of shares and exchanging of resources among affiliated firms (Khanna and Palepu, 2000;Khanna, Palepu, and Srinivasan, 2004). As a result, momentum profits for group firms are higher due to higher sophistication and opacity in information, which is more likely to triggers psychological biases, such as overconfidence and self-attribution suggested by Daniel, Hirshleifer and Subrahmanyam (1998). They argue that those biases are underlying drives of momentum effects. On the other hand, the stabilisation theory suggests that group firms exhibit less momentum effects due to strong motivation to stabilise stock prices of the affiliated firms, or having more stabilisation tools such as using business relationship within the groups (Chui et al., 2003). Consequently, independent firms are more likely to produce higher momentum effects resulted from less stabilisation trading. Accordingly, comparing momentum performance between the two kinds of firms throws light on identifying the underlying source of momentum effects. I use a sample approximately 1.5 times of the number of firms used by Chui et al. The null hypothesis is that there is no significant momentum differential between group and independent firms. The stabilisation (psychological bias) theory will be accepted in the presence of significant larger momentum profits among independent (group) firms.
Consistent with Fu and Wood (2010), this study finds strong Taiwanese momentum during April to Auguest. Strength of the momentum, however, does not show significant difference between independent and group firms. The lack of discrepancy is inconsistent with either of the two above hypotheses, nor with the strong Taiwanese evidence reported by Chui et al. (2003). This research contributes to momentum literature by sheding further light to findings by Chui et al (2003).
The rest of this paper is structured as follows. The following section present data and methodology. Section 4 reports empirical results, and section 5 concludes.

Data and Methodology
I use the annual published survey of 'Business Groups in Taiwan' compiled by China Credit Information Service from 1988 to 2004, identifying 305 group firms in the sample of 675 firms with the remaining as independent firms. For a firm to be eligible as a group firm by the 'Business Groups in Taiwan', all the following criteria have to be fulfilled: (1) There are three or more firms in the group.
(2) The parent firm(s) is (are) locally registered and more than 51% of the ownership is held by private firms.
(3) At least one of the following mechanisms is used to construct the affiliation: (a) In the case of investing subsidiaries through (parent) corporations, rather than through individuals, subsidiaries should be held at least by 50% ownerships, or mutually be held by at least 33%, or be held with the parent(s) as the largest owner(s).
(b) More than half of the ownership of both the parent(s) and the subsidiaries is held by the same equity-holder(s).
(c) More than half of the directors, monitors, executive stockholders, stockholders are representing the investing firms, and the general manager of the parent(s) is the person who also is the general manager of the subsidiaries.
(d) More than half of the directors, monitors, executive stockholders, stockholders are representing the investing firm, and the general manager of the parent(s) and that of the subsidiaries have relationships in forms of spouse, father (or mother) versus sons (or daughters), or grandfather (or grandmother) versus grandsons (or granddaughters).
(e) Both the parent(s) and the subsidiaries are controlled by the same supervisory organisation.
Following the methodology in Chui et al. (2003) for Asian markets, the loser (bottom 30%), medium (middle 40%), and winner (top 30%) portfolios are ranked on the past J-month returns and are held for the next K months. The sample is from July 1975 to December 2003. Momentum portfolio return is equally-weighted. Table 1 documents a couple of interesting resultings. Firstly, either among independent or group firms, a significant momentum over the April-Auguest period is apparently detected. Secondly, differential momentum returns between the two groups of stocks are too weak to decide which of the two hypotheses is more compelling than the other. The F statistics is also not large enough to refute the hypothesis of no apparently difference of momentum profits across calendar months. The ambiguous evidence is not consistent with strong evidence reported by Chui et al. (2003).  Table 2 in below reveals a consistency of no evident difference of performance of momentum strategies across independent and group firms, for the situations with ranking/holding periods of 9 and 12 months, respectively.  ISSN 1923-4023 E-ISSN 1923

Subperiod Analysis
The subperiod analysis shown in Table 3 still do not report significant differential momentum effect between the two types of firms, consistent with findings in previous tables.

Conclusions
Consistent with Fu and Wood (2010), this study finds strong Taiwanese momentum during April to Auguest. Strength of the momentum, however, does not show significant difference between independent and group firms. The lack of discrepancy is inconsistent with either of the the psychological bias or stabilisation hypotheses mentioned previously, nor with the strong Taiwanese evidence reported by Chui et al. (2003). The results are bound by the research restriction of sample years. Research of more recent years warrants future research.