Biblio

Although computing students may enjoy when their instructors teach using analogies, it is unknown to what extent these analogies are useful for their learning. This study examines the value of analogies when used to introduce three introductory computing topics. The value of these analogies may be evident during the teaching process itself (short term), in subsequent exams (long term), or in students' ability to apply their understanding to related non-technical areas (transfer). Comparing results between an experimental group (analogy) and control group (no analogy), we find potential value for analogies in short term learning. However, no solid evidence was found to support analogies as valuable for students in the long term or for knowledge transfer. Specific demographic groups were examined and promising preliminary findings are presented.

Novice programmers exhibit a repertoire of affective states over time when they are learning computer programming. The modeling of frustration is important as it informs on the need for pedagogical intervention of the student who may otherwise lose confidence and interest in the learning. In this paper, contextual and keystroke features of the students within a Java tutoring system are used to detect frustration of student within a programming exercise session. As compared to psychological sensors used in other studies, the use of contextual and keystroke logs are less obtrusive and the equipment used (keyboard) is ubiquitous in most learning environment. The technique of logistic regression with lasso regularization is utilized for the modeling to prevent over-fitting. The results showed that a model that uses only contextual and keystroke features achieved a prediction accuracy level of 0.67 and a recall measure of 0.833. Thus, we conclude that it is possible to detect frustration of a student from distilling both the contextual and keystroke logs within the tutoring system with an adequate level of accuracy.

In this paper, we focus on energy management of distributed generators (DGs) and energy storage system (ESS) in microgrids (MG) considering uncertainties in renewable energy and load demand. The MG energy management problem is formulated as a two-stage stochastic programming model based on optimization principle. Then, the optimization model is decomposed into a mixed integer quadratic programming problem by using discrete stochastic scenarios to approximate the continuous random variables. A Scenarios generation approach based on time-homogeneous Markov chain model is proposed to generate simulated time-series of renewable energy generation and load demand. Finally, the proposed stochastic programming model is tested in a typical LV network and solved by Matlab optimization toolbox. The simulation results show that the proposed stochastic programming model has a better performance to obtain robust scheduling solutions and lower the operating cost compared to the deterministic optimization modeling methods.

Hash functions, such as SHA (secure hash algorithm) and MD (message digest) families that are built upon Merkle-Damgard construction, suffer many attacks due to the iterative nature of block-by-block message processing. Chum and Zhang [4] proposed a new hash function construction that takes advantage of the randomize-then-combine technique, which was used in the incremental hash functions, to the iterative hash function. In this paper, we implement such hash construction in three ways distinguished by their corresponding padding methods. We conduct the experiment in parallel multi-threaded programming settings. The results show that the speed of proposed hash function is no worse than SHA1.
 

Dependence on web applications is increasing very rapidly in recent time for social communications, health problem, financial transaction and many other purposes. Unfortunately, presence of security weaknesses in web applications allows malicious user's to exploit various security vulnerabilities and become the reason of their failure. Currently, SQL Injection (SQLI) and Cross-Site Scripting (XSS) vulnerabilities are most dangerous security vulnerabilities exploited in various popular web applications i.e. eBay, Google, Facebook, Twitter etc. Research on defensive programming, vulnerability detection and attack prevention techniques has been quite intensive in the past decade. Defensive programming is a set of coding guidelines to develop secure applications. But, mostly developers do not follow security guidelines and repeat same type of programming mistakes in their code. Attack prevention techniques protect the applications from attack during their execution in actual environment. The difficulties associated with accurate detection of SQLI and XSS vulnerabilities in coding phase of software development life cycle. This paper proposes a classification of software security approaches used to develop secure software in various phase of software development life cycle. It also presents a survey of static analysis based approaches to detect SQL Injection and cross-site scripting vulnerabilities in source code of web applications. The aim of these approaches is to identify the weaknesses in source code before their exploitation in actual environment. This paper would help researchers to note down future direction for securing legacy web applications in early phases of software development life cycle.

The objective of this paper is to explore the current notions of systems and “System of Systems” and establish the case for quantitative characterization of their structural, behavioural and contextual facets that will pave the way for further formal development (mathematical formulation). This is partly driven by stakeholder needs and perspectives and also in response to the necessity to attribute and communicate the properties of a system more succinctly, meaningfully and efficiently. The systematic quantitative characterization framework proposed will endeavor to extend the notion of emergence that allows the definition of appropriate metrics in the context of a number of systems ontologies. The general characteristic and information content of the ontologies relevant to system and system of system will be specified but not developed at this stage. The current supra-system, system and sub-system hierarchy is also explored for the formalisation of a standard notation in order to depict a relative scale and order and avoid the seemingly arbitrary attributions.
 

Principles of agile information systems development (ISD) have attracted the interest of practice as well as research. The goal of this literature review is to validate, update and extend previous reviews in terms of the general state of research on agile ISD. Besides including categories such as the employed research methods and data collection techniques, the importance of theory is highlighted by evaluating the theoretical foundations and contributions of former studies. Since agile ISD is rooted in the IS as well as software engineering discipline, important outlets of both disciplines are included in the search process, resulting in 482 investigated papers. The findings show that quantitative studies and the theoretical underpinnings of agile ISD are lacking. Extreme Programming is still the most researched agile ISD method, and more efforts on Scrum are needed. In consequence, multiple research gaps that need further research attention are identified.