1,720,963 research outputs found
A Unified Conceptual Model for Distributed Transactions
No full textDistributed transaction processing systems can be unnecessarily complex when crosscutting concerns, e.g. logging, concurrency controls, transaction management, and access controls, are scattered throughout the transaction processing logic or tangled into otherwise cohesive modules. Aspect orientation has the potential of reducing this kind of complexity with better modularization and encapsulation of crosscutting concerns, but currently aspect-oriented programming languages and frameworks only allow weaving of advice, i.e., the logic for crosscutting concerns, into contexts derived from traditional executable structures, such as method calls, constructors, and exceptions. This paper lays a foundation for weaving advice into distributed transactions by considering them to be target contexts and identifying interesting points in time, i.e., events, into which advice may be woven. To establish this foundation, we survey common approaches to transaction management, distribution, and execution; concurrency controls; and rollback. We then capture these ideas in a conceptual model, called Unified Model for Distributed Transactions (UMDT), and show that this model accurately describes all the common approaches. In the end, this model defines interesting point in time relative to transactions in general and what a transaction may know at those points in time, i.e., its context. A brief discussion of advice weaving and the potential for reducing complexity with transaction-specific aspects is provided, but the details of the actual weaving are left for another paper
The Repercussions of the COVID-19 Pandemic on Higher Education and its implications for Syrian Refugees Students (An Analytical Descriptive Study)
Get PDFهدفت الدراسة الحالية إلى الكشف عن أهم التحديات والصعوبات التي تواجه طلبة الجامعات الأردنية من اللاجئين السوريين (جامعة اليرموك، اّل البيت، جامعة الزرقاء الخاصة) نتيجة أعباء الجائحة عن طريق قياس عدد من المؤشرات ذات العلاقة بالدراسة، فضلا عن كشف أثر بعض المتغيرات المستقلة في تلك التحديات والصعوبات وذلك بالاعتماد على المنهج الوصف التحليلي وباستخدام عدة أساليب إحصائية. وتمثلت أداة جمع البيانات في استبانة أعدت خصيصا لتحقيق أهداف الدراسة جرى توزيعها على عينة عشوائية من الطلبة إلكترونيا. وتوصلت الدراسة لعدد من النتائج وأهمها ضرورة تنفيذ برامج تعليمية إرشادية ونفسية وبرامج دعم اقتصادية لتوفير تكاليف الدراسة الناجمة من التعلم عن بعد، وأكدت الدراسة أن اللاجئين أكثر تأثرا في الجائحة مقارنة بأفراد المجتمع المضيف. This study aims to reveal the most important challenges and difficulties that refugee students faced in Jordanian universities (e.g., Yarmouk University, AL Al-Bayt, and the Private Zarqa University) due to the COVID-19 pandemic through measuring a different of indicators that are related, in addition, to identify some of the independent variables on e-educational challenges. In the study, the analytical description approach was used. The data collection tool is a questionnaire, which was distributed to a random sample of students electronically. Results show that the necessity to implement educational and psychological counseling programs and economic support programs to support the e-Learning costs. The study confirmed that refugees are the most affected students with the pandemic compared to the host communit
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Improving Reuse of Distributed Transaction Software with Transaction-Aware Aspects
Get PDFImplementing crosscutting concerns for transactions is difficult, even using Aspect-Oriented Programming Languages (AOPLs) such as AspectJ. Many of these challenges arise because the context of a transaction-related crosscutting concern consists of loosely-coupled abstractions like dynamically-generated identifiers, timestamps, and tentative value sets of distributed resources. Current AOPLs do not provide joinpoints and pointcuts for weaving advice into high-level abstractions or contexts, like transaction contexts. Other challenges stem from the essential complexity in the nature of the data, operations on the data, or the volume of data, and accidental complexity comes from the way that the problem is being solved, even using common transaction frameworks. This dissertation describes an extension to AspectJ, called TransJ, with which developers can implement transaction-related crosscutting concerns in cohesive and loosely-coupled aspects. It also presents a preliminary experiment that provides evidence of improvement in reusability without sacrificing the performance of applications requiring essential transactions. This empirical study is conducted using the extended-quality model for transactional application to define measurements on the transaction software systems. This quality model defines three goals: the first relates to code quality (in terms of its reusability); the second to software performance; and the third concerns software development efficiency. Results from this study show that TransJ can improve the reusability while maintaining performance of TransJ applications requiring transaction for all eight areas addressed by the hypotheses: better encapsulation and separation of concern; loose Coupling, higher-cohesion and less tangling; improving obliviousness; preserving the software efficiency; improving extensibility; and hasten the development process
Weaving Crosscutting Concerns into Distributed Transactions in Aspect
No full textImplementing crosscutting concerns for transactions is difficult, even using Aspect-Oriented Programming Languages (AOPL) such as AspectJ. Many of these challenges are because the context of transaction-related crosscutting concern is often a context consisting of loosely-coupled abstractions like dynamically generated identifiers, timestamps, and tentative value sets for distributed resources. Current AOPL do not provide joinpoints and pointcuts for weaving of advice into high-level abstractions, like transactions. Other challenges stem from essential complexity in the nature of the data, operations on the data, or the volume of data, and accidental complexity comes from the way that the problem is being solved even using common transaction frameworks. This paper describes an extension to AspectJ, called TransJ, with which developers can implement transaction-related concerns in cohesive and loosely coupled aspects. It also presents a preliminary experiment that we hope will provide evidence of improvement in reusability without sacrificing performance of applications requiring transactions
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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