Miracle-dz/UniFAR-FTUs huggingface dataset:
Playtime Measurement With Survival Analysis

Maximizing product use is a central goal of many businesses, which makes retention and monetization two central analytics metrics in games. Player retention may refer to various duration variables quantifying product use: total playtime or session playtime are popular research targets, and active playtime is well-suited for subscription games. Such research often has the goal of increasing player retention or conversely decreasing player churn. Survival analysis is a framework of powerful tools well suited for retention type data. This paper contributes new methods to game analytics on how playtime can be measured using survival analysis. These methods include visualizations, metrics, and an AB-test based on the survival curve. All these methods work on censored data and enable computation of confidence intervals. This is especially important in time- and sample-limited data that occurs during game development. Throughout this paper, we illustrate the application of these methods to the development of the Hipster Sheep mobile game.
Vehicular Fog Computing: Architecture, Use Case, and Security and Forensic Challenges

Vehicular fog computing extends the fog computing paradigm to conventional vehicular networks. This allows us to support more ubiquitous vehicles, achieve better communication efficiency, and address limitations in conventional vehicular networks in terms of latency, location awareness, and real-time response (typically required in smart traffic control, driving safety applications, entertainment services, and other applications). Such requirements are particularly important in adversarial environments (e.g., urban warfare and battlefields in the Internet of Battlefield Things involving military vehicles). However, there is no one widely accepted definition for vehicular fog computing and use cases. Thus, in this article, we formalize the vehicular fog computing architecture and present a typical use case in vehicular fog computing. Then we discuss several key security and forensic challenges and potential solutions.
The Effects of Cooperative Learning on Different Ability Level Students' Perceptions of the Middle School Classroom Environment.

The Effects of Cooperative Learning on Different Ability Level Students' Perceptions of the Science Classroom Environment The purpose of this study was to determine the effects of different types of cooperative learning environments on low, average, and high ability students' perceptions of the middle school science classroom environment. To analyze the impact of these effects, students in no cooperative learning environments, average cooperative learning environments, and high cooperative learning environments were compared to one another on five measures of perceptions: cohesiveness, satisfaction, friction, competitiveness, and difficulty. Fifteen teachers and 1185 students participated in the study which was conducted in the sixth, seventh, and eighth grades of two middle schools. Several types of data were collected: pretest and posttest data, descriptive data gathered from a questionnaire completed by the classroom teachers to assess the quality and quantity of cooperative learning, informal interviews with teachers, and classroom observation data. Using the My Class Inventory (MCI), all participants of the study were administered a pretest and posttest. A 3 x 3 Factorial Mult_variate Analysis of Covariance was use to statistically analyze the data. The classroom was used as the unit of analysis. The perception dimensions on the pretest were used as the covariates, and posttest perception dimensions as the dependent variables. A Tukey post hoc procedure was employed to determine which groups were significantly different from each other. The results indicated the dimensions of cohesiveness and competitiveness were significant for the main effect of type of cooperative learning environment. Students in the no cooperative learning environments perceived the science classroom as more cohesive than the students in the average and high cooperative learning environments. There was no significant difference between the high cooperative and average cooperative learning environments on this dimension. On the dimension of competitiveness, the average cooperative learning classes perceived themselves as less competitive than the no and high cooperative learning classes. There was no difference between the no cooperative learning classes and the high cooperative learning classes. Cohesiveness with ability level was significant where low ability students perceive the science classroom as more cohesive than their average ability peers, and high ability students perceive their science learning environment as the least cohesive of the three ability levels. No significant interaction effects were found between the type of cooperative learning environment and ability level. The dimensions of satisfaction, friction, and difficulty were not significant. The qualitative data werr. used to aid in the interpretation of the statistical resuts. The implications and recommendations for science educators, teacher educators and researchers are given.
Power Allocation and Multiuser Scheduling for Delay-Limited Communications Exploiting Only Channel Statistics

This paper considers a delay-constrained wireless communication system in which delay constraint is represented as an outage rate probability constraint within a transmission of K-block Rayleigh flat-fading channels. Given a multiuser time-division (TD) multiplexing system with users' delay constraints, our aim is to minimize the overall transmit power by optimizing the power allocation and the time sharing (i.e., the number of assigned blocks) among the users. The central transmitter (or scheduler) is assumed to have only the channel statistics (CST) while the mobile receivers (or users) have perfect instantaneous channel state information. This problem is of great importance for communication systems where the data rates are preset and the transmission cost is to be minimized. Our contributions are twofold. Firstly, we derive an analytic equation for the minimum power to support a given rate with an outage probability constraint if the number of assigned blocks for a user is known a priori. On the other hand, by constraining the upper bounds of the outage rate requirements, we show that the optimal time-sharing parameters can be found using convex optimization after relaxation. Our proposed solution hence first finds the time-sharing parameters by proper mapping from the relaxed optimum, and then uses the minimum power equations to obtain the corresponding optimal power distribution.
Image Compression using DCT based Compressive Sensing and Vector Quantization

Compressive sensing (CS) provides a mathematical framework for utilizing the potentiality of sparse nature of the commonly used signals and has been the subject of scientific research in recent years. CS involves the compression of the data at the first step of image acquisition. This paper presents an image compression algorithm based on DCT based CS and Vector Quantization (VQ). It has been observed from the implementation of the Proposed CS-VQ algorithm that the proposed algorithm gives better PSNR and visual quality when compared with the existing CS-VQ algorithm. The results obtained are even comparable with JPEG algorithm but only when small queue size is considered. The basic concept behind the CS states that small collections of non-adaptive linear projections of a sparse signal can efficiently helps in the reconstruction of the image through the image data sent to the decoder making use of some optimization procedure.
Large-scale CCG Induction from the Groningen Meaning Bank

In present CCG-based semantic parsing systems, the extraction of a semantic grammar from sentence-meaning examples poses a computational challenge. An important factor is the decomposition of the sentence meaning into smaller parts, each corresponding to the meaning of a word or phrase. This has so far limited supervised semantic parsing to small, specialised corpora. We propose a set of heuristics that render the splitting of meaning representations feasible on a largescale corpus, and present a method for grammar induction capable of extracting a semantic CCG from the Groningen Meaning Bank.
Published Weighted Social Networks Privacy Preservation Based on Community Division

Social network not only contains privacy information but also contains large valuable data for researching. It is very critical to balance the utility of data and the power of privacy preservation for published network. This paper proposes privacy preservation based on community division algorithm to preserve the privacy of published weighted social network. The algorithm firstly changes the directed graph into undirected graph whose weight is replaced by relationship strength and takes the node similarity into consideration while dividing communities, then perturb randomly in local structures to generate the published graph. NMI is used to verify the accuracy of community division, the results of three datasets prove that the algorithm can protect the privacy and guarantee the data utility of the graph structure at the same time.
Nitro-fatty Acid Metabolome: Saturation, Desaturation, β-Oxidation, and Protein Adduction*

Nitrated derivatives of fatty acids (NO2-FA) are pluripotent cell-signaling mediators that display anti-inflammatory properties. Current understanding of NO2-FA signal transduction lacks insight into how or if NO2-FA are modified or metabolized upon formation or administration in vivo. Here the disposition and metabolism of nitro-9-cis-octadecenoic (18:1-NO2) acid was investigated in plasma and liver after intravenous injection in mice. High performance liquid chromatography-tandem mass spectrometry analysis showed that no 18:1-NO2 or metabolites were detected under basal conditions, whereas administered 18:1-NO2 is rapidly adducted to plasma thiol-containing proteins and glutathione. NO2-FA are also metabolized via β-oxidation, with high performance liquid chromatography-tandem mass spectrometry analysis of liver lipid extracts of treated mice revealing nitro-7-cis-hexadecenoic acid, nitro-5-cis-tetradecenoic acid, and nitro-3-cis-dodecenoic acid and corresponding coenzyme A derivatives of 18:1-NO2 as metabolites. Additionally, a significant proportion of 18:1-NO2 and its metabolites are converted to nitroalkane derivatives by saturation of the double bond, and to a lesser extent are desaturated to diene derivatives. There was no evidence of the formation of nitrohydroxyl or conjugated ketone derivatives in organs of interest, metabolites expected upon 18:1-NO2 hydration or nitric oxide (•NO) release. Plasma samples from treated mice had significant extents of protein-adducted 18:1-NO2 detected by exchange to added β-mercaptoethanol. This, coupled with the observation of 18:1-NO2 release from glutathione-18:1-NO2 adducts, supports that reversible and exchangeable NO2-FA-thiol adducts occur under biological conditions. After administration of [3H]18:1-NO2, 64% of net radiolabel was recovered 90 min later in plasma (0.2%), liver (18%), kidney (2%), adipose tissue (2%), muscle (31%), urine (6%), and other tissue compartments, and may include metabolites not yet identified. In aggregate, these findings show that electrophilic FA nitroalkene derivatives (a) acquire an extended half-life by undergoing reversible and exchangeable electrophilic reactions with nucleophilic targets and (b) are metabolized predominantly via saturation of the double bond and β-oxidation reactions that terminate at the site of acyl-chain nitration.
Life‐History Evolution in Guppies. VII. The Comparative Ecology of High‐ and Low‐Predation Environments

Prior research has demonstrated a strong association between the species of predators that co‐occur with guppies and the evolution of guppy life histories. The evolution of these differences in life histories has been attributed to the higher mortality rates experienced by guppies in high‐predation environments. Here, we evaluate whether there might be indirect effects of predation on the evolution of life‐history patterns and whether there are environmental differences that are correlated with predation. To do so, we quantified features of the physical and chemical environment and the population biology of guppies from seven high‐ and low‐predation localities. We found that high‐predation environments tend to be larger streams with higher light levels and higher primary productivity, which should enhance food availability for guppies. We also found that guppy populations from high‐predation environments have many more small individuals and fewer large individuals than those from low‐predation environments, which is caused by their higher birth rates and death rates. Because of these differences in size distribution, guppies from high‐predation environments have only one‐fourth of the biomass per unit area, which should also enhance food availability for guppies in these localities. Guppies from high‐predation sites allocate more resources to reproduction, grow faster, and attain larger asymptotic sizes, all of which are consistent with higher levels of resource availability. We conclude that guppies from high‐predation environments experience higher levels of resource availability in part because of correlated differences in the environment (light levels, primary productivity) and in part as an indirect consequence of predation (death rates and biomass density). These differences in resource availability can, in turn, augment the effect of predator‐induced mortality as factors that shape the evolution of guppy life‐history patterns. We found no differences in the invertebrate communities from high‐ and low‐predation localities, so we conclude that there do not appear to be multitrophic, indirect effects associated with these differences in predation.
The Generalized Dynamic-Factor Model: Identification and Estimation

This paper proposes a factor model with infinite dynamics and nonorthogonal idiosyncratic components. The model, which we call the generalized dynamic-factor model, is novel to the literature and generalizes the static approximate factor model of Chamberlain and Rothschild (1983), as well as the exact factor model la Sargent and Sims (1977). We provide identification conditions, propose an estimator of the common components, prove convergence as both time and cross-sectional size go to infinity at appropriate rates, and present simulation results. We use our model to construct a coincident index for the European Union. Such index is defined as the common component of real GDP within a model including several macroeconomic variables for each European country.
Effect of Microtubule Disruption on Neuronal Spread and Replication of Demyelinating and Nondemyelinating Strains of Mouse Hepatitis Virus In Vitro

ABSTRACT The isogenic host attachment spike protein recombinant demyelinating strain of mouse hepatitis virus (MHV) (RSA59) and the nondemyelinating strain (RSMHV2) differ in their abilities to infect distinct types of neural cells, spread from cell to cell, and induce subsequent demyelination and axonal loss. The differential demyelination properties of RSA59 and RSMHV2 may be a function of spike protein-mediated neuronal transport. Disruption of microtubules with colchicine and vinblastine significantly blocks neuronal transport and reduces the replication of RSA59, whereas RSMHV2 remains unaffected.
A near-optimum precoding technique for downlink multi-user MIMO transmissions

We consider the multiple input-multiple output broadcast channel (MIMO-BC) where an array equipped with M antennas transmits distinct information to K users, each equipped with N antennas. Perfect channel knowledge is assumed, so that each receiver knows its own N × M MIMO channel, and the transmitter knows all K MIMO channels. We propose a linear precoding and combining technique, called multi-user eigenmode transmission (MET), which uses a linear transmission strategy based on zero-forcing beamforming for maximizing the weighted sum rate. On a frame-by-frame basis, MET distributes up to M spatially multiplexed streams for one or more users. We show that the sum rate performance of a related zero-forcing strategy with receiver antenna selection scales optimally as the number of users K increases without bound. For the finite case of users with equal average signal-to-noise ratio (SNR), numerical simulations show that MET outperforms all previous linear techniques uniformly over a range of relevant SNRs. Numerical results for a conventional cellular network with three sectors per cell show that MET multi-user MIMO increases the median system throughput by about 40 percent compared to a baseline system using closed-loop single-user MIMO. We show how a novel MET architecture that coordinates antennas across co-located sectors nearly doubles the throughput of the baseline system with no additional radio frequency (RF) hardware.
Blood Pressure and Heart Rate Variabilities in Normotensive and Hypertensive Human Beings

Blood pressure and heart rate variabilities were studied in 89 ambulant normotensive or essential hypertensive subjects in whom blood pressure was recorded intra-arterially for 24 hours (Oxford method) under standardized living conditions. Data were analyzed beat to beat by a computer to provide mean values of the 48 half hours of the 24-hour period. Variabilities were assessed by the standard deviation and variation coefficients separately obtained for each half hour, as well as by the standard deviations and variation coefficients obtained by averaging the 48 mean values. In each subject, blood pressure and heart rate varied markedly either among or within half hours, indicating the existence of relatively long- and short-term variabilities during the 24 hours. When averaged for all subjects, the long-term variabilities showed only one systematic component, i.e., the marked reduction occurring during sleep. Sleep was further responsible for a marked reduction in the short-term blood pressure and heart rate variabilities. These variabilities showed marked (though nonsystematic) modifications, even outside sleep, which were positively related to the blood pressure and heart rate means. Modifications in blood pressure and heart rate means and short-term variabilities were also positively related to each other. All these features were common to normotensives and hypertensives. In hypertensives, the absolute long and short-term blood pressure variabilities were greater than in normotensives, but the percent blood pressure variabilities were similar. Heart rate variabilities (both absolute and percent) were similar in normotensive and hypertensive subjects. Heart rate variabilities were also similar whether the subjects had impaired or preserved baroreflex control of heart rate (vasoactive drug technique). These findings uncover a number of factors that are associated with and responsible for blood pressure and heart rate variabilities in human beings. The nature of these factors suggest a primary role of central nervous mechanisms in the production of these phenomena and in the overall cardiovascular modulation, with no substantial difference between conditions of normal and chronically elevated blood pressure.
Magnetic resonance imaging of the coronary arteries

Summary Despite progress in prevention and early diagnosis, coronary artery disease (CAD) remains one of the leading causes of mortality in the world. For many years, invasive X-ray coronary angiography has been the method of choice for the diagnosis of significant CAD. However, up to 40% of patients referred for elective X-ray coronary angiography have no clinically significant stenoses. These patients still remain subjected to the potential risks of X-ray angiography. As an alternative, magnetic resonance imaging (MRI) is currently one of the most promising techniques for noninvasive imaging of the coronary arteries. O ver the past two decades, many technical developments have been implemented that have led to major improvements in coronary MRI. Nowadays, both anatomical and functional information can be obtained with high temporal and spatial resolution and good image quality. In this review we will discuss the technical foundations and current status of clinical coronary MRI, and some potential future applications.
Effectiveness and Safety of Tenofovir Gel, an Antiretroviral Microbicide, for the Prevention of HIV Infection in Women

Vaginal Gel Versus HIV HIV prevention technologies for women are urgently needed, especially in sub-Saharan Africa where young women bear the greatest burden of the HIV epidemic. Abdool Karim et al. (p. 1168; published online 19 July) present the results of the CAPRISA 004 randomized control trial. The nearly 3-year-long trial, conducted in urban and rural South African women, tested the efficacy of a vaginal gel containing the antiretroviral drug tenofovir in preventing HIV infection. The dosing strategy required application of the gel both before and after coitus, and with this regime HIV infection was reduced by approximately 39% overall, by 54% in women with high adherence to the protocol, and with no increase in overall adverse event rates. Tenofovir in a vaginal gel formulation shows significant protection against HIV infection in a randomized control trial. The Centre for the AIDS Program of Research in South Africa (CAPRISA) 004 trial assessed the effectiveness and safety of a 1% vaginal gel formulation of tenofovir, a nucleotide reverse transcriptase inhibitor, for the prevention of HIV acquisition in women. A double-blind, randomized controlled trial was conducted comparing tenofovir gel (n = 445 women) with placebo gel (n = 444 women) in sexually active, HIV-uninfected 18- to 40-year-old women in urban and rural KwaZulu-Natal, South Africa. HIV serostatus, safety, sexual behavior, and gel and condom use were assessed at monthly follow-up visits for 30 months. HIV incidence in the tenofovir gel arm was 5.6 per 100 women-years (person time of study observation) (38 out of 680.6 women-years) compared with 9.1 per 100 women-years (60 out of 660.7 women-years) in the placebo gel arm (incidence rate ratio = 0.61; P = 0.017). In high adherers (gel adherence > 80%), HIV incidence was 54% lower (P = 0.025) in the tenofovir gel arm. In intermediate adherers (gel adherence 50 to 80%) and low adherers (gel adherence < 50%), the HIV incidence reduction was 38 and 28%, respectively. Tenofovir gel reduced HIV acquisition by an estimated 39% overall, and by 54% in women with high gel adherence. No increase in the overall adverse event rates was observed. There were no changes in viral load and no tenofovir resistance in HIV seroconverters. Tenofovir gel could potentially fill an important HIV prevention gap, especially for women unable to successfully negotiate mutual monogamy or condom use.
Discussing side effects of over‐the‐counter medicines: impact of adding percentage data

Objectives Discussing side effects with patients continues to be a difficult area of practice. Questions arise as to how many should be mentioned and which ones. The way such information is presented can affect drug‐taking decisions. This study examined how over‐the‐counter (OTC) medicine users are influenced by numerical risk estimates of side effects.