Homological Algebra for Persistence Modules

We develop some aspects of the homological algebra of persistence modules, in both the one-parameter and multi-parameter settings, considered as either sheaves or graded modules. The two theories are different. We consider the graded module and sheaf tensor product and Hom bifunctors as well as their derived functors, Tor and Ext, and give explicit computations for interval modules. We give a classification of injective, projective, and flat interval modules. We state Kunneth theorems and universal coefficient theorems for the homology and cohomology of chain complexes of persistence modules in both the sheaf and graded modules settings and show how these theorems can be applied to persistence modules arising from filtered cell complexes. We also give a Gabriel-Popescu theorem for persistence modules. Finally, we examine categories enriched over persistence modules. We show that the graded module point of view produces a closed symmetric monoidal category that is enriched over itself.Comment: 41 pages, accepted by Foundations of Computational Mathematic

Shelf Based Out-of-Stocks in the Context of Employee Density

The purpose of this paper is to investigate the effect of employee density on shelf based out-of-stocks, i.e. situations when products are physically present at stores, but not on the marked sale positions. In addition, for the first time, these relations were analyzed among different retail formats. By using POS estimation method, shelf based out-of-stock rates were measured for 80 different FMCG products in 97 retail stores. For analyzing the impact of employee density on the average shelf based OOS rate in modern and traditional retail formats, curvilinear hierarchical regression and moderation analyses were used. The results showed that the relation between employee density and shelf based out-of-sock varied among different formats. While it was not significant in convenience stores, in modern formats it was quadratic (stores with too many or too few employees per square meter were related to higher levels of shelf based OOS). The obtained results suggest that store managers should be aware of the effects of employee organization on product availability. The attention was also dedicated to potential problems and managerial implications concerning the employees' number in retail stores, regarding traditional and modern trading formats

A comparative overview on Blockchain-based applications for Software Engineering

In less than a decade, blockchain technology has seen a rise in popularity due to its innate security properties and overall disruptive potential. Surpassing its initial use in fintech and cryptocurrencies, blockchain and similar distributed ledger technologies have been used in healthcare, supply chain management, and within the public sector. However, recent studies show that blockchain-based technologies have found uses in software engineering (SE) as well. Namely, blockchain technologies can be used in all phases of the Software Development Life Cycle - software requirements, the engineering/development process, software testing and quality assurance, as well as software maintenance. In this paper, by utilizing existing literature regarding blokchain technologies and SE, we provide insight on which type of blockchain technology could be beneficial for each of the use-cases in SE, highlighting the advantages and potential disadvantages. We discuss various consensus mechanism support, smart contracts technology, as well as storage solutions, tu finally give recommendations for identified use-cases.Publishe

AN AUTOMATED GRADING FRAMEWORK FOR THE MOBILE DEVELOPMENT PROGRAMMING LANGUAGE KOTLIN

With the recent rise of the Kotlin programming language as the main contender for Android mobile development, very few courses in Higher Education Institutions exist which incorporate Kotlin as one of the main languages. In addition, various online course platforms which offer learning Kotlin are still very low in number, and the ones that do exist are expensive. In this paper, an e-learning framework for the Kotlin programming language is presented, supporting automatic grading of given assessments. This framework is aimed at students who already have basic knowledge of Java (or similar) programming languages, and want to switch to mobile development. The solution focuses on the development of an interactive course in Kotlin. Furthermore, to compare our solution with commercially available ones, we point out the disadvantages of currently available Kotlin courses, such as the level of previous knowledge needed, or a need for a specific development environment.Publishe

New Market Segmentation Knowledge in the Function of Bioeconomy Development in Serbia

Sustainability of companies in modern market conditions greately depends on the knowledge. In order to improve their business processes and satisfy the needs of their customers, managers have to rely on new marketing knowledge, especially in new sectors such as bioeconomy. The aim of this paper is to investigate potential added value to Serbian organic food market segmentation researches (belonging to preconditions of further bioeconomy development) when implementing new marketing knowledge – food-related lifestyle market segmentation and scales’ testings. The results point out to adventurous consumers as the most important current and future market for organic food. Besides being the most educated (what was already established for consumers accepting organic food well in previous domestic researches), it is the first time that consumers accepting organic food in larger extent are brought in connection to their inclusion of the whole family in the preparation of meals and acceptance of novelties in cooking. It is also the first time to identify that there is a segment in domestic conditions for which price is not the greatest obstacle for increasing organic food consumption. That can be of the great importance for all actors (both national and foreign) operating at domestic food market

LEARNING THE KOTLIN PROGRAMMING LANGUAGE USING AN AUTOGRADING SYSTEM

In modern curricula for Computer Science (CS) and Information Technology (IT), one of the more popular classes is mobile development. With the recent rise of the Kotlin programming language as a main contender for Android development, very few courses in Higher Education Institutions (HEIs) exist which incorporate Kotlin as a main language. Furthermore, online courses which offer learning Kotlin are very limited, or require a high subscription price. More importantly, neither online, nor HEI courses offer an automatically graded system for student assignments in Kotlin. In this paper, a tool for learning for learning the Kotlin programming language with is presented which supports automatic grading of assignments. As the Kotlin language is itself designed to interoperate fully with Java, this tool, developed by the authors, is aimed at CS and IT students who have already have basic knowledge of Java (or similar) programming languages, and want to switch to mobile development. Our solution focuses on the development of an interactive course in Kotlin meant primarily for Java developers. The assignments in the course also compare certain approaches to a solution in Java and Kotlin side-by-side. The solution is developed as a web application, not needing a separate compiler, libraries or an integrated development environment. Furthermore, to compare our solution with commercially available ones, we point out the disadvantages of currently available Kotlin courses, such as the level of previous knowledge needed, or a need for a specific development environmentPublishe

Serbia within the European context: An analysis of premature mortality

<p>Abstract</p> <p>Background</p> <p>Based on the global predictions majority of deaths will be collectively caused by cancer, cardiovascular diseases, and traffic accidents over the coming 25 years. In planning future national health policy actions, inter – regional assessments play an important role. The purpose of the study was to analyze similarities and differences in premature mortality between Serbia, EURO A, EURO B, and EURO C regions in 2000.</p> <p>Methods</p> <p>Mortality and premature mortality patterns were analysed according to cause of death, by gender and seven age intervals. The study results are presented in relative (%) and absolute terms (age-specific and age-standardized death rates per 100,000 population, and age-standardized rates of years of life lost – YLL per 1,000). Direct standardization of rates was undertaken using the standard population of Europe. The inter-regional comparison was based on a calculation of differences in YLL structures and with a ratio of age-standardized YLL rates per 1,000. A multivariate generalized linear model was used to explore mortality of Serbia and Europe sub-regions with <it>ln </it>age-specific death rates. The dissimilarity was achieved with a p ≤ 0.05.</p> <p>Results</p> <p>According to the mortality pattern, Serbia was similar to EURO B, but with a lower average YLL per death case. YLL patterns indicated similarities between Serbia and EURO A, while SRR YLL had similarities between Serbia and EURO B. Compared to all Europe sub-regions, Serbia had a major excess of premature mortality in neoplasms and diabetes mellitus. Serbia had lost more years of life than EURO A due to cardiovascular, genitourinary diseases, and intentional injuries. Yet, Serbia was not as burdened with communicable diseases and injuries as were EURO B and EURO C.</p> <p>Conclusion</p> <p>With a premature mortality pattern, Serbia is placed in the middle position of the Europe triangle. The main excess of YLL in Serbia was due to cardiovascular, malignant diseases, and diabetes mellitus. The results may be used for assessment of unacceptable social risks resulting from health inequalities. Within intentions to reduce an unfavourable premature mortality gap, it is necessary to reconsider certain local polices and practices as well as financial and human resources incorporated in the prevention of disease and injury burden.</p

The frequency of buying cured meat products in the context of consumers’ store choices

Research background: In the sector of cured meat production and sale, companies are struggling to attract as many consumers as possible. Because of this, special attention should be dedicated to the examination of consumer behavior towards cured meat products. In relation to this, there are studies, including different types of factors, such as geographic, economic and socio-demographic. In this paper, consumer behavior regarding cured meat products was investigated from the aspect of consumers’ store choices. Purpose of the article: The paper examines the frequency of buying cured meat products on a monthly basis, taking into account factors that influence consumers store choices. Based on the buying frequency, all respondents have been divided into low, medium and high frequency segments, which were compared in relation to store choosing factors. Methods: The research was conducted on a sample that included 449 respondents from the city of Novi Sad. They were interviewed in 2019, by the use of a specially designed questionnaire. For processing the data, one way ANOVA and Tukey post-hoc test were implemented. Findings & Value added: The obtained results have shown that the largest percent of respondents – nearly 60% - belong to medium frequency segment, followed by high frequency segment (about one third of respondents) and low frequency segment (less than 10%). The closeness to place of living, appropriate working hours, wide assortment, quality of products and favorable prices belong to the top 5 most influential factors in each of the segments. These findings can be used by manufacturers and retailers when making decisions regarding production and marketing activities

Serbian Organic Food Consumer Research and Bioeconomy Development

The bioeconomy has been introduced as a potential answer to some of the issues that modern mankind is confronted with: Climate change, industrial restructuring, food security, health, and energy security. In its goal to establish sustainable green growth, the bioeconomy relies heavily on the agriculture and food sector, whereas a special place belongs to organic food. Increasing organic food consumption depends on understanding organic food consumers. Research of their profile, both worldwide and in Serbia, has failed to find their common characteristics. In this paper, results of research with the first application of a logit model in defining domestic organic food consumers are presented. The results showed they were urban, highly educated, and with higher income. The greatest obstacle for increasing their future consumption of organic food was its insufficient availability. The paper provides managerial implications as well