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关键词： computer science   algorithm   predictions   interpolative coding   PNG   JPEG LS   JPEG 2000 lossless  

摘要： A new approach is proposed for lossless raster image compression employing interpolative coding. A new multifunction prediction scheme is presented first. Then, interpolative coding, which has not been applied frequently for image compression, is explained briefly. Its simplification is introduced in regard to the original approach. It is determined that the JPEG LS predictor reduces the information entropy slightly better than the multi-functional approach. Furthermore, the interpolative coding was moderately more efficient than the most frequently used arithmetic coding. Finally, our compression pipeline is compared against JPEG LS, JPEG 2000 in the lossless mode, and PNG using 24 standard grayscale benchmark images. JPEG LS turned out to be the most efficient, followed by JPEG 2000, while our approach using simplified interpolative coding was moderately better than PNG. The implementation of the proposed encoder is extremely simple and can be performed in less than 60 lines of programming code for the coder and 60 lines for the decoder, which is demonstrated in the given pseudocodes.

关键词： Batteries   Computer science   Electrocatalysis   Energy grids and networks   Solar cells  

摘要： Transitioning from fossil fuels to renewable energy sources is a critical global challenge;it demands advances - at the materials, devices and systems levels - for the efficient harvesting, storage, conversion and management of renewable energy. Energy researchers have begun to incorporate machine learning (ML) techniques to accelerate these advances. In this Perspective, we highlight recent advances in ML-driven energy research, outline current and future challenges, and describe what is required to make the best use of ML techniques. We introduce a set of key performance indicators with which to compare the benefits of different ML-accelerated workflows for energy research. We discuss and evaluate the latest advances in applying ML to the development of energy harvesting (photovoltaics), storage (batteries), conversion (electrocatalysis) and management (smart grids). Finally, we offer an overview of potential research areas in the energy field that stand to benefit further from the application of ML. Machine learning is poised to accelerate the development of technologies for a renewable energy future. This Perspective highlights recent advances and in particular proposes Acc(X)eleration Performance Indicators (XPIs) to measure the effectiveness of platforms developed for accelerated energy materials discovery.

关键词： Cognitive skills   computer anxiety   computer self-efficacy   Nigeria   Social Science undergraduates   tertiary institution  

摘要： This study investigated the influence of computer self-efficacy, computer anxiety, and cognitive skills on the use of electronic library resources by social science undergraduates in a tertiary institution in Nigeria. Survey research design was adopted and stratified random sampling technique was used to select 869 sample size from a population of 1452 social science undergraduates across five departments. A total of 793 questionnaire was properly filled and collated which equals a response rate of 91.3% from the population sample. Findings from the study revealed that there were significant relationships among computer selfefficacy, computer anxiety, cognitive skills, and use of electronic library resources by the respondents. Computer self-efficacy, computer anxiety, and cognitive skills individually and jointly had a significant influence on the use of electronic library resources of the respondents. Therefore, library management in the tertiary institution should give due consideration to computer self-efficacy, computer anxiety, and cognitive skills of the respondents when planning to enhance their use of electronic library resources among others.

关键词： Computer science   Information technology   Research management  

摘要： The country’s automation research might need a renewed focus to rekindle past successes.

关键词： operational research   actuarial science   parallel computing   computer science   decision-making process  

摘要： This paper aims to find the actuarial tables that best represent the occurrences of mortality and disability in the Brazilian Armed Forces, thus providing a better dimensioning of the costs of military pensions to be paid by the pension system. To achieve this goal, an optimization software was developed that tests 53 actuarial tables for the death of valid military personnel, 21 boards for entry into the disability of assets, and 21 boards for mortality of invalids. The software performs 199 distinct adherence tests for each table analyzed through linear aggravations and de-escalations in the probabilities of death and disability. The statistical-mathematical method used was the chi-square adherence test in which the selected table is the one with the null hypothesis "observed data" equal to the "expected data" with the highest degree of accuracy. It is expected to bring a significant contribution to society, as a model of greater accuracy reduces the risk of a large difference between the projected cost and the cost observed on the date of the year, thus contributing to the maintenance of public governance. Additionally, the unprecedented and dual nature of the methodology presented here stands out. As a practical contribution, we emphasize that the results presented streamline the calculation of actuarial projections, reducing by more than 90% the processing times of calculations referring to actuarial projections of retirees from the armed forces. As a limitation of the study, we emphasize that, although possibly replicable, the database was restricted only to the Brazilian Armed Forces.

关键词： Topic evolution   Topic embedding   Scientometrics   Informetrics   Data mining   Similarity metrics  

摘要： The study of topic evolution aims to analyze the behavior of different research fields by utilizing various features such as the relationships between articles. In recent years, many published papers consider more than one field of study which has led to a significant increase in the number of inter-field and interdisciplinary articles. Therefore, we can analyze the similarity/dissimilarity and convergence/divergence of research fields based on topic analysis of the published papers. Our research intends to create a methodology for studying the evolution of the research fields. In this paper, we propose an embedding approach for modeling each research topics as a multidimensional vector. Using this model, we measure the topic's distances over the years and investigate how topics evolve over time. The proposed similarity metric showed many advantages over other alternatives (such as Jaccard similarity) and it resulted in better stability and accuracy. As a case study, we applied the proposed method to subsets of computer science for experimental purposes, and the results were quite comprehensible and coherent.

关键词： Graphical modeling   conceptual modeling   computer science   competence model   higher education  

摘要： Modeling is an integral part of many computing-related disciplines and thus also represents a curricular core component in computing education in tertiary education. Competence models in which modeling is integrated at least to some extent already exist in some of these disciplines. However, for the core component of graphical modeling, a competence model that illuminates the relevant competences in detail is still lacking. Therefore, we develop a competence model for graphical modeling with the aim to make teaching and especially assessments in the field more competence-oriented. This article reports on the first two studies conducted to develop and validate the competence model for graphical modeling. In the first study, the structure of the competence model was developed based on theories and approaches of educational science. Competences relevant for graphical modeling were deductively derived from literature and existing university course descriptions using techniques of qualitative content analysis. The result of the first study is a preliminary competence model. In the second study, the preliminary competence model was reviewed by means of an expert rating in the modeling community. The competence model was revised and refined based on these findings and subsequent expert discussions. The main result of the investigation represents the competence model for graphical modeling, which includes a total of 74 competence facets at different cognitive process levels in the five content areas of "model understanding and interpreting," "model building and modifying," "values, attitudes, and beliefs," "metacognitive knowledge and skills," and "social-communicative skills."

关键词： Capital punishment   death sentences   racial resentment   lynching  

摘要： We explore the annual number of death sentences imposed on black and white offenders within each US state from 1989 through 2017, with particular attention to the impact of aggregate levels of racial resentment. Controlling for general ideological conservatism, homicides, population size, violent crime, institutional and partisan factors, and the inertial nature of death sentencing behavior, we find that racial hostility translates directly into more death sentences, particularly for black offenders. Racial resentment itself reflects each state's history of racial strife;we show powerful indirect effects of a history of lynching and of racial population shares. These effects are mediated through contemporaneous levels of racial resentment. Our findings raise serious questions about the appropriateness of the ultimate punishment, as they show its deep historical and contemporary connection to white racial hostility toward blacks.

关键词： Computer science   Publishing   Sustainability  

摘要： Three charts from the world of research, selected byNatureeditors.

关键词： Computer science   Information technology   Machine learning  

摘要： A machine with a grasp of cause and effect could learn more like a human, through imagination and regret.