Miracle-dz/UniFAR-FTUs huggingface dataset:
Percentile Optimization for Markov Decision Processes with Parameter Uncertainty

Markov decision processes are an effective tool in modeling decision making in uncertain dynamic environments. Because the parameters of these models typically are estimated from data or learned from experience, it is not surprising that the actual performance of a chosen strategy often differs significantly from the designer's initial expectations due to unavoidable modeling ambiguity. In this paper, we present a set of percentile criteria that are conceptually natural and representative of the trade-off between optimistic and pessimistic views of the question. We study the use of these criteria under different forms of uncertainty for both the rewards and the transitions. Some forms are shown to be efficiently solvable and others highly intractable. In each case, we outline solution concepts that take parametric uncertainty into account in the process of decision making.
Transportation Oil Demand Consumer Preferences and Asymmetric Price Responses : Some UK Evidence

The Surrey Energy Economics Centre (SEEC) consists of members of the Department of Economics who work on energy economics, environmental economics and regulation. The Department of Economics has a long-standing tradition of energy economics research from its early origins under the leadership of Professor Colin Robinson. This was consolidated in 1983 when the University established SEEC, with Colin as the Director; to study the economics of energy and energy markets. SEEC undertakes original energy economics research and since being established it has conducted research across the whole spectrum of energy economics, including the international oil market, as well as a range of other academic papers, books and monographs. SEEC also runs workshops and conferences that bring together academics and practitioners to explore and discuss the important energy issues of the day. SEEC also attracts a large proportion of the department's PhD students and oversees the MSc in Energy Economics & Policy. Many students have successfully completed their MSc and/or PhD in energy economics and gone on to very interesting and rewarding careers, both in academia and the energy industry. ABSTRACT The aim of this paper is to (i) establish the role of asymmetric price decompositions in UK road transportation fuel demand, (ii) make explicit the impact of the underlying energy demand trend and (iii) disaggregate the estimation for gasoline and diesel demand as separate commodities. Dynamic UK transport oil demand functions are estimated using the Seemingly Unrelated Structural Time Series Model with decomposed prices to allow for asymmetric price responses. The importance of starting with a flexible modelling approach that incorporates both an underlying demand trend and asymmetric price response function is highlighted. Furthermore, these features can lead to different insights and policy implications than might arise from a model without them. As an example, a zero elasticity for a price-cut is found (for both gasoline and diesel) implying that price reductions do not induce demand for road transportation fuel in the UK. The paper illustrates the importance of joint modelling of gasoline and diesel demand incorporating both asymmetric price responses and stochastic underlying energy demand trends.
Compression of Pseudo-periodic Signals Using 2D Wavelet Transform

An improved method to compress of pseudo-periodic 1-dimensional signals like voiced speech, music, ECG etc is suggested. The pitch synchronous property of such signals is utilized to increase the efficiency of compression, to minimize losses and thus to enhance the quality of the reconstruction. Results show higher signal to noise ratio, higher compression ratio and lower percentage distortion with the new method of 2-D compression as compared to 1-D compression. A new method employing the k-means clustering algorithm is used to determine the periodicity of signals.
Globalization, Biculturalism and Cosmopolitanism

Globalization forces many managers to increasingly interact with new cultures, even if these managers remain in their home countries. This may be particularly true of managers in emerging markets, many of whom experience an encroaching US culture due to media, migration, and trade, as well as the importation of US-style business education. This study explores the possibility of applying acculturation insights developed in the immigrant and sojourner contexts to the context of local managers in emerging markets. By exploring the acculturation of Mexican managers in Mexico, we help to redress what has been identified as a key omission in prior acculturation research — the acculturation of a majority population. Our results suggest that Mexican managers who are bicultural or culturally independent (cosmopolitan) are more likely to be in upper management positions in Mexico. Our study supplements earlier work supporting the efficacy of biculturalism in minority populations. It also supports a growing body of research that conceptualizes individuals who rate themselves low on similarity to two cultures as being cosmopolitans and not marginalized individuals who experience difficulty in life. Mondialisation, biculturalisme et cosmopolitisme : l’acculturation des cadres supérieurs mexicains (Kate Gillespie, J. Brad McBride and Liesl Riddle) La mondialisation oblige de plus en plus les managers à interagir avec de nouvelles cultures, même si ceux-ci demeurent dans leurs pays d’origine. Ceci est sans doute le cas des managers issus des marchés émergents, la majorité d’entre eux étant confrontée à une culture américaine envahissante, que ce soit du fait des médias, de la migration, du commerce ou de l’importation d’une éducation en management à l’américaine. L’étude explore la possibilité d’appliquer certains résultats de la recherche sur l’acculturation dans des contextes d’immigrants et de séjourneurs aux contextes des managers locaux dans les marchés émergents. En explorant l’acculturation des managers mexicains au Mexique, nous redressons ce qui a été identifié comme une grave omission de la recherche sur l’acculturation jusqu’à aujourd’hui, à savoir l’acculturation de la population majoritaire. Nos résultats suggèrent que les managers mexicains biculturels ou culturellement indépendants (cosmopolites) ont plus de chances d’occuper des postes de cadres supérieurs au Mexique. Notre étude complète des précédents travaux appuyant l’efficacité du biculturalisme chez les populations minoritaires. Elle vient en appui à une recherche de plus en plus importante qui conceptualise les individus qui se classent en bas de l’échelle en termes de similitude à deux cultures de cosmopolites et non d’individus marginalisés faisant l’expérience d’une vie difficile.
Quality matters: usage-based app popularity prediction

In recent years, mobile application (app) economy has grown to a huge market but it is only the top apps that are able to turn this boom into significant revenues. In this paper, we study how the quality of an app, as reflected in how people start to use it, is linked to the popularity of the app. We show that features extracted from the Device Analyzer dataset, describing the aggregate usage of the app, can be used to predict its popularity. We also look at the connection between app popularity and the past popularity of other apps from the same publisher and find a surprisingly small correlation between the two.
European Conference on Information Systems ( ECIS ) 2008 Improving Data Quality of Health Information Systems : A Holistic Design-Oriented Approach

Structural changes and increasing market dynamics in the healthcare sector intensify the health providers’ need for cost-savings and process optimisation. To address actual drawbacks the adoption of eHealth is currently seen as opportunity to improve not only effectiveness and efficiency but also quality of health services. Data quality aspects will therefore gain in importance. As the actual use of the data is outside of the systems designers’ control and in contrast to empiricaland practitionerbased research approaches it is the goal of this contribution to present a first design-oriented approach that helps systems designers to understand the reality of the different stakeholders of healthcare. For this purpose a conceptual model with 44 design elements is presented. For the analysis of the domain two different perspectives are identified. An inter-organisational view defines all elements needed to depict the boundaries of healthcare organisations in order to enable exchange, sharing and integration of data, while the intra-organisational view helps to analyse the inner organisational reality. As not only technical but mainly interand intra-organisational issues are actually restricting data exchange, the proposed conceptual model provides a holistic framework for the improvement of data quality which is the prerequisite of high quality health services.
Photolytic manipulation of Ca2+ and the time course of slow, Ca(2+)‐activated K+ current in rat hippocampal neurones.

1. Experiments were performed on hippocampal CA1 pyramidal cells to investigate the time course of a slow, Ca(2+)‐activated K+ current that follows a burst of action potentials. At a temperature of 27‐30 degrees C, this current rises to a peak 200‐400 ms following the cessation of Ca2+ entry before decaying to baseline in 4‐8s. 2. Intracellular recordings were made using electrodes containing the photolabile calcium buffers nitr‐5 or DM‐nitrophen loaded appropriately with Ca2+. Under these conditions, photolysis of the compound using an ultraviolet flashlamp caused an instantanous increase in cytoplasmic Ca2+ throughout the cell. The response to flash photolysis was a membrane hyperpolarization with an onset limited by the membrane time constant. Multiple (up to twenty) flash responses could be generated. 3. The postspike slow after‐hyperpolarization (AHP) and flash‐induced hyperpolarizations showed a common sensitivity to the beta‐adrenergic receptor agonist isoprenaline. 4. Following a burst of spikes, the current underlying an AHP in progress could be terminated or reduced by photolysis‐induced production of calcium buffer from diazo‐4 within the cell. This action was rapid (within the setting time of the flash artifact, i.e. < 10 ms) despite the fact that the manipulation occurred 400‐500 ms following the end of Ca2+ entry. 5. Partial block of the slow AHP by buffer production was accompanied by an increase in the time to peak of the event. 6. The time to peak of the slow AHP could also be manipulated by experiments which altered the spatial distribution of Ca2+ entry, such as production of calcium spikes or dendritic depolarization by glutamate in the presence of tetrodotoxin. 7. The Ca(2+)‐dependent K+ current responsible for the slow AHP responds immediately to increase or decreases in cytoplasmic Ca2+. It seems likely, therefore, that the slow AHP is controlled solely by changes in free Ca2+ and that the time course is governed by the redistribution of cytoplasmic Ca2+ following activity‐induced entry through voltage‐ or receptor‐operated channels.
An adaptive approach for online segmentation of multi-dimensional mobile data

With increasing availability of mobile sensing devices including smartphones, online mobile data segmentation becomes an important topic in reconstructing and understanding mobile data. Traditional approaches like online time series segmentation either use a fixed model or only apply an adaptive model on one dimensional data; it turns out that such methods are not very applicable to build online segmentation for multiple dimensional mobile sensor data (e.g., 3D accelerometer or 11 dimension features like 'mean', 'variance', 'covariance', 'magnitude', etc). In this paper, we design an adaptive model for segmenting real-time accelerometer data from smartphones, which is able to (a) dynamically select suitable dimensions to build a model, and (b) adaptively pick up a proper model. In addition to using the traditional residual-style regression errors to evaluate time series segmentation, we design a rich metric to evaluate mobile data segmentation results, including (1) traditional regression error, (2) information retrieval style measurements (i.e., precision, recall, F-measure), and (3) segmentation time delay.
Combined endosulfan and cypermethrin-induced toxicity to embryo–larval development of Rhinella arenarum

ABSTRACT The combined effects of two widely used pesticides, endosulfan and cypermethrin, on survival of embryo–larval development of the South American toad (Rhinella arenarum) were examined. The toxicity bioassays were performed according to the AMPHITOX test. Embryos and larvae were exposed to mixtures of these pesticides at equitoxic ratios from acute or chronic exposure to evaluate interaction effects. The results were analyzed using both Marking’s additive index and combination index (CI)–isobologram methods. Acute (96-h) and intermediate (168-h) toxicity of endosulfan–cypermethrin mixtures remained almost constant for larvae and embryos, but when exposure duration was increased, there was a significant elevation in toxicity, obtaining chronic (240-h) no-observed-effect concentrations (NOEC) values of 0.045 and 0.16 mg/L for embryos and larvae, respectively. These are environmentally relevant concentrations that reflect a realistic risk of this pesticide mixture to this native amphibian species. The toxicity increment with the exposure duration was coincident with the central nervous system development on embryos reaching the larval period, the main target organ of these pesticides. The interactions of the pesticide mixtures at acute and chronic exposure were antagonistic for embryo development (CI > 1), and additive (CI = 1) for larvae, while chronic exposure interactions were synergistic (CI < 1) for both developmental periods. Data indicated that endosulfan–cypermethrin mixtures resulted in different interaction types depending on duration and developmental stage exposed. As a general pattern and considering conditions of overall developmental period and chronic exposure, this pesticide mixture usually applied in Argentine crop fields is synergistic with respect to toxicity for this native amphibian species.
Classical Alzheimer features and cholinergic dysfunction: towards a unifying hypothesis?

Objective – Our autopsy studies show possible links between classical Alzheimer pathology and decreased expression of nicotinic acetylcholine receptors. For further elucidation we are now using in vitro models. We report preliminary evidence for the impact of β‐amyloid on nicotinic receptor expression in hippocampal dissociation culture. Methods – Cultures (E18 rats) were grown in a serum‐free medium and incubated at 8 days in vitro for 3 days with 1 µM Aβ1–42. Expression of α4, α7, and β2 nicotinic receptor subunit protein was assessed immunohistochemically and rated semiquantitatively. Results – Aβ1–42 incubation resulted in a massive reduction of α4 protein‐expressing neurons, this effect was less pronounced for the α7 and β2 subunit protein. Conclusion – These findings provide first evidence for a direct impact of classical Alzheimer pathology features on nicotinic receptor expression in vitro. Our model will be useful for testing the potential of drugs to stop or reverse these effects.
Comparison of three tests for virulent Yersinia enterocolitica

Magnesium oxalate agar was found to select against virulent types of Yersinia enterocolitica. Small colonies isolated from magnesium oxalate agar which were presumably virulent generally contained no detectable virulence-specific plasmids, did not agglutinate with virulence-specific antiserum, and exhibited various degrees of virulence in mice. Results indicate that the virulence potential of a Y. enterocolitica isolate cannot always be identified by these in vitro methods and suggest that virulence also involves other factors yet to be identified.
Recovering Asymmetric Communities in the Stochastic Block Model

We consider the sparse stochastic block model in the case where the degrees are uninformative. The case where the two communities have approximately the same size has been extensively studied and we concentrate here on the community detection problem in the case of unbalanced communities. In this setting, spectral algorithms based on the non-backtracking matrix are known to solve the community detection problem (i.e., do strictly better than a random guess) when the signal is sufficiently large namely above the so-called Kesten-Stigum threshold. In this regime and when the average degree tends to infinity, we show that if the community of a vanishing fraction of the vertices is revealed, then a local algorithm (belief propagation) is optimal down to Kesten-Stigum threshold and we quantify explicitly its performance. Below the Kesten-Stigum threshold, we show that, in the large degree limit, there is a second threshold called the spinodal curve below which, the community detection problem is not solvable. The spinodal curve is equal to the Kesten-Stigum threshold when the fraction of vertices in the smallest community is above <inline-formula><tex-math notation="LaTeX">$p^*=\frac{1}{2}-\frac{1}{2\sqrt{3}}$</tex-math><alternatives> <inline-graphic xlink:href="miolane-ieq1-2758201.gif"/></alternatives></inline-formula>, so that the Kesten-Stigum threshold is the threshold for solvability of the community detection in this case. However when the smallest community is smaller than <inline-formula><tex-math notation="LaTeX">$p^*$</tex-math><alternatives> <inline-graphic xlink:href="miolane-ieq2-2758201.gif"/></alternatives></inline-formula>, the spinodal curve only provides a lower bound on the threshold for solvability. In the regime below the Kesten-Stigum bound and above the spinodal curve, we also characterize the performance of best local algorithms as a function of the fraction of revealed vertices. Our proof relies on a careful analysis of the associated reconstruction problem on trees which might be of independent interest. In particular, we show that the spinodal curve corresponds to the reconstruction threshold on the tree.
Skewed Libor Market Model and Gaussian HJM Explicit Approaches to Rolled Deposit Options

A simple exotic option (floor on rolled deposit) is studied in the shifted log-normal Libor Market (LMM) and Gaussian HJM models. The shifted log-normal LMM exhibits a controllable volatility skew. An explicit approach is used for both models. Using approximations the price in the LMM is obtained without Monte Carlo simulation. The more precise approximation uses a twisted version of the perdictor-corrector adapted to explicit solutions. The results of the approximation are surprisingly good.
Storage Layout and I/O Performance Tuning for IBM® Red Brick® Data Warehouse

Although Red Brick performance depends on the logical database design, the placement and allocation of data files in the disk subsystem is another significant performance factor. There are many choices in the configuration and design of the physical database layout. This article reviews best practices propagated by storage and database vendors and presents measurements that compare storage layout alternatives for Red Brick. This leads to specific I/O configuration and tuning guidelines for IBM Red Brick Data Warehouse. This article assumes that the reader has basic knowledge of Red Brick Data Warehouse. Notices and trademarks The furnishing of this document does not imply giving license to any IBM patents. References in this document to IBM products, Programs, or Services do not imply that IBM intends to make these available in all countries in which IBM operates. The information contained in this publication does not include any product warranties, and any statements provided in this document should not be interpreted as such. The following terms are trademarks or registered tra demarks of International Business Machines Corporation in the United States, other countries, or both: AIX Enterprise Storage Server DB2 DB2 Universal Database IBM Informix Red Brick Other products or service names may be trademarks or registered trademarks of their respective owners. © Copyright International Business Machines Corporation 2002. All rights reserved. Table of
Under Consideration for Publication in Theory and Practice of Logic Programming on the Implementation of Gnu Prolog

GNU Prolog is a general-purpose implementation of the Prolog language, which distinguishes itself from most other systems by being, above all else, a native-code compiler which produces standalone executables which don't rely on any byte-code emulator or meta-interpreter. Other aspects which stand out include the explicit organization of the Prolog system as a multipass compiler, where intermediate representations are materialized , in Unix compiler tradition. GNU Prolog also includes an extensible and high-performance finite domain constraint solver, integrated with the Prolog language but implemented using independent lower-level mechanisms. This article discusses the main issues involved in designing and implementing GNU Prolog: requirements, system organization , performance and portability issues as well as its position with respect to other Prolog system implementations and the ISO standardization initiative.
The Effects on Students’ Conceptual Understanding of Electric Circuits of Introducing Virtual Manipulatives Within a Physical Manipulatives-Oriented Curriculum

This study investigates whether Virtual Manipulatives (VM) within a Physical Manipulatives (PM)-oriented curriculum affect conceptual understanding of electric circuits and related experimentation processes. A pre–post comparison study randomly assigned 194 undergraduates in an introductory physics course to one of five conditions: three experimental conditions with different PM and VM sequences and two control conditions with only PM or VM. Conceptual tests assessed students’ understanding. Instructors’ journals, video data, and interviews provided process-related data. Results showed interplay between manipulative and circuit types. For simple circuits, PM and VM use similarly impacted students’ understanding. However, VM better facilitated understanding than PM for complex circuits: PM users, unlike VM users, encountered process-related problems that prevented development of an appropriate conceptual model because only VM afforded a view of current-flow. When students used VM before PM for complex circuits, they developed the appropriate conceptual model to use in the PM phase.
On the Fair Comparison of FEC Schemes

Two new metrics for the high-level comparison of Forward Error Correction (FEC) schemes are proposed and applied to the study of Turbo and LDPC codes. These new metrics retain simplicity and allow us to compare FEC schemes by factoring in their relative complexity. Furthermore, for the case of Turbo and LDPC codes, we determine the number $\cal I$ of LDPC iterations that correspond to an iteration performed by a Turbo decoder under the constraint that an equal number of elementary operations is performed at the receiver. As a practical example, we apply these metrics to the comparison of the FEC schemes debated in the ITU-T G.hn Working Group (WG) confirming the technical validity of the selection of the LDPC-based proposal over the Turbo Code one.