Miracle-dz/UniFAR-FTUs huggingface dataset:
Structural Estimation of the Chilean Auction for School Meals

Introduction The Chilean government provides breakfast and lunch for 2.5 million children daily in primary and secondary public schools during the school year. In a developing country where about 14 percent of children under the age of 18 live below the poverty line, many students depend on these free meals as a key source of nutrition. This social program is a key element in turning the goal of equal opportunities into a reality by compensating for the social deficits suffered by children who come from socioeconomically vulnerable sectors. It is also a key aspect in implementing preventive health care as nourished children are likely to be healthier. Since 1997 contracts to private catering firms that provide this service are awarded through a singleround, sealed-bid, first-price combinatorial auction (CA), that is, a multi-unit auction in which bidders can bid on combinations or packages of territorial units the country is divided into. Meal services are standardized and firms compete in prices. Around 20 firms participate in each auction; each firm submit many bids (hundreds or even thousands) containing from just one to several territorial units. The CA has been used every year since its inception awarding more than $3 billion of contracts (US$577 million were awarded in 2008). (See Epstein et al. (2002), Epstein et al. (2004), and Catalán et al. (2009) for a more detailed description). Practical experience and academic research have shown that the design of an auction may have an important impact on its outcome; good designs can result in large savings, while poor designs may lead to large losses for the auctioneer (Milgrom 2004). Typically, the performance of an auction is critically determined by the firms’ cost structure and their strategic behavior, both of which are usually not directly observed by the auctioneer. The main objective of this work is to conduct an empirical study of bidding data to uncover important aspects of the firms’ cost structure and their strategic behavior in the Chilean auction for school meals. Based on this information, we analyze and suggest important improvements to the auction design. Although our study is based on a specific auction, our modeling and identification methodology is fairly general and could be used in other contexts of CAs.
Seed Returns 1 Gone Today , Here Tomorrow : Behavioral Causes of Product Returns in the Agribusiness Industry

Hybrid seed suppliers experience excessive and costly rates of seed returns from dealers, who order in advance of grower demand realization and may return unsold seeds at the end of the season. Here we develop a formal dynamic model of the interaction of sales effort allocation and dealer hoarding behavior to understand the dynamics of corn seed returns through a model-based field study. Sales representatives know they should carefully gather information on grower demand for seed types and quantities to improve their demand forecast (positioning effort). However, they abandon time-consuming seed positioning late in the sales cycle to push out dealers’ inflated orders and quickly meet revenue quotas. Such push effort leads to excessive returns in the next period, generating more inflated orders by dealers and increasing the total sales that agents must achieve to meet their quota, requiring them to push still more seed. Depending on the availability of sales resources, this biased sales effort allocation can generate a self-perpetuating stream of returns. Our analysis highlights the importance of adequately managing sales resources to ensure desired system performance while maintaining system robustness.
Concepts and Theories of Pure Competition.

Abstract : A classical formulation of the marketplace is examined from three different theoretical view points, and the three solutions that result are contrasted. When the number of participants is small, the solutions are very different, both in their form and in their quantitative predictions. As the size of the market increases, however, they all converge to a common solution, despite the wide disparity in the underlying assumptions.
Are Spot Freight Rates Stationary

In the recent literature, empirical tests of stationarity of freight rates often conclude that spot freight rates are non-stationary processes. However, many maritime economists would argue that the freight rate cannot exhibit asymptotically explosive behaviour, as implied by non-stationarity, in a perfectly competitive freight market. This paper restates the theoretical arguments behind mean reversion and boundedness of the spot freight rate process and suggests that the failure to reject non-stationarity may be due to the weak power of the tests most frequently used. We employ a non-linear version of the Augmented Dickey-Fuller (ADF) test, based on an exponentially smooth-transition autoregressive model (ESTAR). This test enhances the power against mean-reverting nonlinear alternative hypotheses compared to the linear alternative for traditional ADF tests. Our empirical results show, in line with maritime economic theory, that freight rates in both dry-bulk and tanker markets are non-linear stationary. © 2006 LSE and the University of Bath
Monte Carlo pricing of Bermudan-style derivativeswith lower and upper bound methods

The Longstaff-Schwartz algorithm is widely used for pricing Bermudan options. It allows Monte Carlo simulation to take into account the early-exercise feature of a Bermudan option. The method utilizes multi-linear regression to estimate the continuation value of such options. In this thesis, we study the impact of different regressor configurations on the performance of the Longstaff-Schwartz method. We evaluate pricing result in various model settings including the Black-Scholes world, the Heston model and the lognormal Libor market model. By using an upper bound pricing algorithm proposed by Andersen and Broadie, we demonstrate a reliable measure for evaluating the performance of the Longstaff-Schwartz algorithm. We show that regressor configuration plays a significant role in this method, and give recommendations on how to construct effective regressors.
An Optimal Image Thresholding Using Genetic Algorithm

Image segmentation plays an important and basic role in image processing and pattern recognition. Its purpose is to separate areas that do not superpose each other and to obtain the interested target. During the past few years many algorithms for image segmentation have been proposed. The popular technique is the threshold segmentation because of its simplicity and efficiency. Genetic algorithm is the immediate search method that is based on the theory of evolution which natural selection mechanism, parallel and statistics. In this paper, an optimal image thresholding using Genetic Algorithm is proposed. Compared with traditional threshold methods, the proposed method has advantages that it can implement quickly optimal threshold and have good capability and stabilization. The results show that using the proposed method can obtain satisfactory segmentation effect and save the computational time
OF METROLOGICAL SERVICE CENTER OF GRAVITATION AND FUNDAMENTAL METROLOGY RGS-VNIIMS-004 / 98 gr-qc / 9810019 Superluminal propagation of light in gravitational field and non-causal signals : some comments 1

We examine the recent statement by A. Dolgov and I. Novikov that superluminal propagation of light, which is induced by the quantum corrections to the photon propagation in gravitational field, permits non-causal signal propagation. For this purpose we examine the possibility of the existence of non-causal signals in the model case, when characteristic cone of the signal is outside the usual light cone in Minkowski space-time, as it take place in the case of the photon propagation in gravitation field with quantum corrections taking into account. In such model the signal propagates along invariant intervals. It is shown that there are no non-causal signals in the considered model. The recent statement of A. Dolgov and I. Novikov was obtained by using additional supposition that velocity of the signal with respect to the emitter is independent from its motion. Such supposition does not valid in the case of the photon propagation in gravitational field. Moscow 1998 1 This work was supported by the Russian Ministry of Science and the Russian Foundation of Basic Research (grant N 98-02-16414).
SRC: a multicore NPU-based TCP stream reassembly card for deep packet inspection

Stream reassembly is the premise of deep packet inspection, regarded as the core function of network intrusion detection system and network forensic system. As moving packet payload from one block of memory to another is essential for the reason of packet disorder, throughput performance is very vital in stream reassembly design. In this paper, a stream reassembly card SRC is designed to improve the stream reassembly throughput performance. The designed SRC adjusts the sequence of packets on the basis of the multicore network processing unit by managing and reassembling streams through an additional level of buffer. Specifically, three optimistic techniques, namely stream table dispatching, no-locking timeout, and multichannel virtual queue, are introduced to further improve the throughput. To address the critical role of memory size in SRC, the relationship between the system throughput and memory size is analyzed. Extensive experiments demonstrate that the proposed SRC achieves more than 3Gbps in terms of reassembly and submission throughput and triply outperforms the traditional server-based architecture with a lower cost. Copyright © 2013 John Wiley & Sons, Ltd.
Essential roles of the PI3 kinase/Akt pathway in regulating Nrf2-dependent antioxidant functions in the RPE.

PURPOSE To investigate functional interactions between the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and the nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent antioxidant system in cultured human retinal pigment epithelium (RPE) cells. METHODS Cultured ARPE-19 cells were treated with different concentrations of PI3K inhibitors, followed by exposure to sulforaphane, an Nrf2 inducer. Akt phosphorylation was detected by Western blot analysis. Intracellular glutathione (GSH) content was measured by HPLC. Expression of genes downstream of Nrf2, including glutamate-cysteine ligase (GCL) and glutathione S-transferase, was measured by quantitative RT-PCR. Nrf2 activity was measured by a dual luciferase assay after transfection of a reporter plasmid containing the antioxidant response element (ARE). The small interference RNA approach was used to knock down Nrf2 in the RPE. Nrf2 localization was determined by subcellular fractionation and Western blot analyses. RESULTS PI3K inhibitors wortmannin and LY294002 caused dose-dependent cellular and mitochondrial GSH depletion and downregulation of the modulatory subunit of GCL in cultured RPE cells. Both the basal and the induced Nrf2 activities were inhibited by wortmannin and LY294002. Overexpression of a constitutively active form of Akt potentiated Nrf2 activation, and the effect of Akt was blocked by siRNA that knocked down Nrf2. LY294002 also inhibited sulforaphane-induced Nrf2 nuclear translocation. CONCLUSIONS The PI3K/Akt pathway plays key roles in regulating Nrf2-ARE-dependent protection against oxidative stress in the RPE.
Cost-Effectiveness of Hypothetical New Cancer Drugs in Patients with Advanced Small-Cell Lung Cancer: Results of a Markov Chain Model

Background In the last decade, a number of new treatment modalities have been developed for patients with small cell lung cancer (SCLC). The clinical effects are encouraging, but little is known about the costs and cost-effectiveness of new drugs. Methods A Markov chain model has been developed to project patient outcomes and costs for patients with advanced SCLC. All patients in the control group were treated with etoposide–cisplatin chemotherapy. Patients in the study group received a hypothetical new drug. The model consisted of four states: response, stable disease, progressive disease, and death. Estimates of transition probabilities were calculated using published data on survival and recurrence-free survival. For the cost analysis and utility calculation, published data and expert opinion were used as sources. The duration of the follow-up was maximal 2 years. Results The total treatment costs in the etoposide–cisplatin group amounted to €16 038 and in the alternative treatment groups between €16 644 and €18 171. The number of life years and quality adjusted life years (QALYs) gained were very small, around 16 days. The cost-effectiveness ratio varied between €22 208 and €81 443 and the cost–utility ratio varied accordingly. Results of the sensitivity analysis showed that the results were robust in favor of etoposide–cisplatin treatment. Conclusion SCLC is an illness with a poor prognosis which needed substantial healthcare resources to optimise patient survival and overall quality of life. New treatment modalities with better outcome and favourable cost-effective profiles can hopefully be developed.
A Learning-Based Prediction-and-Verification Segmentation Scheme for Hand Sign Image Sequence

We present a prediction-and-verification segmentation scheme using attention images from multiple fixations. A major advantage of this scheme is that it can handle a large number of different deformable objects presented in complex backgrounds. The scheme is also relatively efficient. The system was tested to segment hands in sequences of intensity images, where each sequence represents a hand sign in American Sign Language. The experimental result showed a 95 percent correct segmentation rate with a 3 percent false rejection rate.
MobSafe: cloud computing based forensic analysis for massive mobile applications using data mining

With the explosive increase in mobile apps, more and more threats migrate from traditional PC client to mobile device. Compared with traditional Win+Intel alliance in PC, Android+ARM alliance dominates in Mobile Internet, the apps replace the PC client software as the major target of malicious usage. In this paper, to improve the security status of current mobile apps, we propose a methodology to evaluate mobile apps based on cloud computing platform and data mining. We also present a prototype system named MobSafe to identify the mobile app's virulence or benignancy. Compared with traditional method, such as permission pattern based method, MobSafe combines the dynamic and static analysis methods to comprehensively evaluate an Android app. In the implementation, we adopt Android Security Evaluation Framework (ASEF) and Static Android Analysis Framework (SAAF), the two representative dynamic and static analysis methods, to evaluate the Android apps and estimate the total time needed to evaluate all the apps stored in one mobile app market. Based on the real trace from a commercial mobile app market called AppChina, we can collect the statistics of the number of active Android apps, the average number apps installed in one Android device, and the expanding ratio of mobile apps. As mobile app market serves as the main line of defence against mobile malwares, our evaluation results show that it is practical to use cloud computing platform and data mining to verify all stored apps routinely to filter out malware apps from mobile app markets. As the future work, MobSafe can extensively use machine learning to conduct automotive forensic analysis of mobile apps based on the generated multifaceted data in this stage.
Social Anxiety, Tremor Severity, and Tremor Disability: A Search for Clinically Relevant Measures

Background. While social anxiety has been reported among essential tremor (ET) patients, very little is known about the relation between self-report measures of social anxiety, tremor severity and disability, and cognition. Methods. Sixty-three individuals diagnosed with ET took part in a comprehensive study examining neurocognition and behavioral functioning. A psychiatric diagnostic interview, three social anxiety questionnaires, and an idiographic-based behavioral assessment to pinpoint anxiety provoking situations and related distress were completed. Results. Thirty percent of the participants met diagnostic criteria for social anxiety disorder (SAD). Social anxiety questionnaires were negligibly related to tremor severity and disability. Idiographic behavioral assessment of subjective distress was moderately related to resting tremor severity and disability and strongly related to social anxiety questionnaires scores. Only one cognitive variable was related to tremor severity. Conclusions. These findings suggest that (a) self-report measures of social anxiety with ET patients may underestimate distress; (b) emphasis on tremor severity may be misleading; (c) tremor disability may be a more sensitive and functional measure related to cognition and effect; (d) SAD is wide spread and does not appear to be related to dysregulated executive function; and (e) development of an ET-specific measure of social anxiety is called for.
Diversity-Multiplexing Tradeoff of Wireless Communication Systems With User Cooperation

As one of the key technologies for future wireless communication systems, user cooperation has a great potential in improving the system performance. In this paper, the diversity benefit of user cooperation is evaluated using diversity-multiplexing tradeoff (DMT) as the performance metric. Ways of exploiting the diversity benefit are devised. We investigate two typical channel models, namely, the multiple-access channel (MAC) and the interference channel (IFC). For the MAC, all the terminals are equipped with multiple antennas and the K(K ≥ 2) sources cooperate in a full-duplex mode. We determine the optimal DMT of the channel and propose a compressed-and-forward (CF) based cooperation scheme to achieve the optimal DMT. For the IFC, we consider a two-user channel with single-antenna terminals and full-duplex source cooperation. A DMT upper bound and two DMT lower bounds are derived. The upper bound is derived based on a channel capacity upper bound, and the lower bounds are derived using decode-and-forward (DF) based cooperation schemes. In most channel scenarios, the bounds are found to be tight. This implies that under certain channel scenarios, the optimal DMT of the channel can be achieved by DF-based cooperation schemes.
Old and Young Individuals' Role in Cultural Change

We explore the impact of age on cultural change through simulations of cultural evolution. Our simulations show that common observations about the relationship between old and young naturally emerge from repeated cultural learning. In particular, young individuals are more open to learn than older individuals, they are less effective as cultural models, and they possess less cultural traits. We also show that, being more open to learning, young individuals are an important source of cultural change. Cultural change, however, is faster in populations with both young and old. A relatively large share of older individuals, in fact, allows a population to retain more culture, and a large culture can change in more directions than a small culture. For the same reason, considering age-biased cultural transmission in an overlapping generations model, cultural evolution is slower when individuals interact preferentially with models of similar age than when they mainly interact with older models.
Structured Interviews on the Object-Oriented Paradigm RR/95/182 [EFoCS-7-95]

The method of structured interviewing is an appropriate means of conducting a primary investigation when beginning a programme of research involving di erent empirical techniques because (i) interviewing experienced users from academia and industry should determine if academics are exploring issues that industrialists deem important, (ii) interviewing users from industry helps provide external validity, (iii) users of object-oriented systems have their own views on the bene ts and drawbacks of the paradigm. These opinions could then be used as evidence to decide whether an empirically unsupported practice is justi ed and warrants further, more controlled investigation, and (iv) these views can identify issues that have not been previously considered. Structured interviews, each based on a template of 23 questions, were carried out with 13 experienced object-oriented users to explore problems discussed in the object-oriented literature concerned with high level system understanding, inheritance, software maintenance, and other issues. Interviews lasted between 30 min-
Study of the long-term effect of STDP in areas of spiking neurons

The spike-timing-dependent-plasticity (STDP) is a mechanism for adjusting the efficacies of biological synapses that was observed and studied in vitro. However, the STDP effect for natural neurons in vivo is subject of debate because in several experiments when the neurons are stimulated indirectly by natural paths the STDP effect was insignificant. Starting from these aspects this work studies by simulation the STDP long-term effect on synaptic plasticity in order to determine whether the long-term potentiation (LTP) and the long-term depression (LTD) could compensate each other during long-term activity of the neural network. The results show that for some synapses the weights start to oscillate in small intervals around long term stable values that are different from the limits of the weights variation interval. This behavior is caused by the fact that, indeed, the effects of LTP and LTD compensate each other at certain weight values when the same pattern of the input stimuli is presented repeatedly to the network input. The LTP and LTD compensation that determines long term weights stability to other values than the weight variation limits could improve the sensitivity of the learning process in the biological networks because no neuron specific limitation is introduced.
Adaptive Tracking and Obstacle Avoidance Control for Mobile Robots with Unknown Sliding

An adaptive control approach is proposed for trajectory tracking and obstacle avoidance for mobile robots with consideration given to unknown sliding. A kinematic model of mobile robots is established in this paper, in which both longitudinal and lateral sliding are considered and processed as three time-varying parameters. A sliding model observer is introduced to estimate the sliding parameters online. A stable tracking control law for this nonholonomic system is proposed to compensate the unknown sliding effect. From Lyapunov-stability analysis, it is proved, regardless of unknown sliding, that tracking errors of the controlled closed-loop system are asymptotically stable, the tracking errors converge to zero outside the obstacle detection region and obstacle avoidance is guaranteed inside the obstacle detection region. The efficiency and robustness of the proposed control system are verified by simulation results.
A productivity metric based on statistical pattern recognition

The generally accepted calculation to measure the productivity of a software engineer is based on economic theory and is borrowed from traditional product manufacturing environments. Managers often measure the productivity of a worker to determine merit-based raises or to provide feedback to workers with poor productivity. The assumption is that this calculation of a worker's productivity is directly proportional to a worker's value to the company. The motivation for the approach proposed here is that such relationship may not be algebraically captured with respect to the productivity of software engineers. To better capture the productivity of a software engineer and his value to a company, the productivity problem is reformulated here as a pattern recognition problem and solved using clustering. By defining a general productivity operator, clustering has been used to map the domain of the productivity operator to a range of productivity classes. This new approach has been successfully applied to randomly generated project data and actual project data from the NASA SATC software metric database.