Performance related issues in distributed database systems

The key elements of research performed during the year long effort of this project are: Investigate the effects of heterogeneity in distributed real time systems; Study the requirements to TRAC towards building a heterogeneous database system; Study the effects of performance modeling on distributed database performance; and Experiment with an ORACLE based heterogeneous system

Efficient Distributed Estimation of Inverse Covariance Matrices

In distributed systems, communication is a major concern due to issues such as its vulnerability or efficiency. In this paper, we are interested in estimating sparse inverse covariance matrices when samples are distributed into different machines. We address communication efficiency by proposing a method where, in a single round of communication, each machine transfers a small subset of the entries of the inverse covariance matrix. We show that, with this efficient distributed method, the error rates can be comparable with estimation in a non-distributed setting, and correct model selection is still possible. Practical performance is shown through simulations

Security and Performance Verification of Distributed Authentication and Authorization Tools

Parallel distributed systems are widely used for dealing with massive data sets and high performance computing. Securing parallel distributed systems is problematic. Centralized security tools are likely to cause bottlenecks and introduce a single point of failure. In this paper, we introduce existing distributed authentication and authorization tools. We evaluate the quality of the security tools by verifying their security and performance. For security tool verification, we use process calculus and mathematical modeling languages. Casper, Communicating Sequential Process (CSP) and Failure Divergence Refinement (FDR) to test for security vulnerabilities, Petri nets and Karp Miller trees are used to find performance issues of distributed authentication and authorization methods. Kerberos, PERMIS, and Shibboleth are evaluated. Kerberos is a ticket based distributed authentication service, PERMIS is a role and attribute based distributed authorization service, and Shibboleth is an integration solution for federated single sign-on authentication. We find no critical security and performance issues

Anonymity and Confidentiality in Secure Distributed Simulation

Research on data confidentiality, integrity and availability is gaining momentum in the ICT community, due to the intrinsically insecure nature of the Internet. While many distributed systems and services are now based on secure communication protocols to avoid eavesdropping and protect confidentiality, the techniques usually employed in distributed simulations do not consider these issues at all. This is probably due to the fact that many real-world simulators rely on monolithic, offline approaches and therefore the issues above do not apply. However, the complexity of the systems to be simulated, and the rise of distributed and cloud based simulation, now impose the adoption of secure simulation architectures. This paper presents a solution to ensure both anonymity and confidentiality in distributed simulations. A performance evaluation based on an anonymized distributed simulator is used for quantifying the performance penalty for being anonymous. The obtained results show that this is a viable solution.Comment: Proceedings of the IEEE/ACM International Symposium on Distributed Simulation and Real Time Applications (DS-RT 2018

E-Learning For Software Engineering: A Case Study On Teaching Information Systems Online Group Project With Extreme Programming

This paper reports the experience gained in software engineering group work within the framework of a fourteen week master’s level graduate course on information systems development. Teams of three to five members developed web-based application systems using the Distributed eXtreme Programming (XP) methodology. A case study is proposed to understand the issues encountered by students during the software development process and to determine the impact of XP methodology as well as team members’ geographical distribution on students’ overall performance. We suggest that teaching an information systems group project online with agile methodology (i.e. distributed XP) brings several issues to be considered before and during the development process. This study points out these issues, particularly those regarding student teams’ communication, coordination, and collaboration practices. Improvement of these issues in the future would help educators develop more effective education settings and help students enhance their performance

The Evolutionary Price of Anarchy: Locally Bounded Agents in a Dynamic Virus Game

The Price of Anarchy (PoA) is a well-established game-theoretic concept to shed light on coordination issues arising in open distributed systems. Leaving agents to selfishly optimize comes with the risk of ending up in sub-optimal states (in terms of performance and/or costs), compared to a centralized system design. However, the PoA relies on strong assumptions about agents\u27 rationality (e.g., resources and information) and interactions, whereas in many distributed systems agents interact locally with bounded resources. They do so repeatedly over time (in contrast to "one-shot games"), and their strategies may evolve. Using a more realistic evolutionary game model, this paper introduces a realized evolutionary Price of Anarchy (ePoA). The ePoA allows an exploration of equilibrium selection in dynamic distributed systems with multiple equilibria, based on local interactions of simple memoryless agents. Considering a fundamental game related to virus propagation on networks, we present analytical bounds on the ePoA in basic network topologies and for different strategy update dynamics. In particular, deriving stationary distributions of the stochastic evolutionary process, we find that the Nash equilibria are not always the most abundant states, and that different processes can feature significant off-equilibrium behavior, leading to a significantly higher ePoA compared to the PoA studied traditionally in the literature

Performance Test Automation with Distributed Database Systems

Our previous research paper 2018;A Focus on Testing Issues in Distributed Database Systems' led us to a conclusion that Distributed Database Systems supports many good engineering practices but there is still place for refinements. A Distributed Database (DDB) is formed by a collection of multiple databases logically inter-related in a Computer Network. Apart from managing a plethora of complicated tasks, database management systems also need to be efficient in terms of concurrency, reliability, fault-tolerance and performance. As there has been a paradigm shift from centralized databases to Distributed databases, any testing process, when used in DDB correlates a series of stages for the construction of a DDB project right from the scratch and is employed in homogeneous systems. In this paper, an attempt is made to describe the establishment of Performance Testing with DDB systems. It focuses on the need for maintaining performance and some techniques to achieve performance in DDB systems. Three sample web based systems are tested by using TestMaker, one of the open source software, in order to highlight the helpful role of performance in the context of testing. The strengths and weaknesses of chosen performance testing tools viz., TestMaker, OpenSTA, and httperf are discussed