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Jha P.C.,University of Delhi | Bali S.,Lal Bahadur Shastri Institute of Management | Kumar U.D.,Indian Institute of Management | Pham H.,Rutgers University
Memetic Computing | Year: 2014

In developing software systems, a manager's goal is to design software using limited resources and meet the user requirements. One of the important user requirements concerns the reliability of the software. The decision to choose the right software modules (components) becomes extremely difficult because of the number of parameters to be considered while making the decision. If suitable components are not available, then the decision process is further complicated with build versus buy decisions. In this paper, we have formulated a fuzzy multi-objective approach to optimal decision "build-or-buy" for component selection for a fault-tolerant modular software system under the consensus recovery block scheme. A joint optimization model is formulated where the two objectives are maximization of system reliability and minimization of the system cost with a constraint on delivery time. An example of developing a retail system for small-and-medium-size enterprises is used to illustrate the proposed methodology. © 2013 Springer-Verlag Berlin Heidelberg. Source

Jha P.C.,University of Delhi | Kapur P.K.,University of Delhi | Bali S.,Lal Bahadur Shastri Institute of Management | Kumar U.D.,Indian Institute of Management
International Journal of Reliability, Quality and Safety Engineering | Year: 2010

Computer based systems have increased dramatically in scope, complexity, pervasiveness. Most industries are highly dependent on computers for their basic day to day functioning. Safe & reliable software operations are an essential requirement for many systems across different industries. The number of functions to be included in a software system is decided during the software development. Any software system must be constructed in such a way that execution can resume even after the occurrence of failure with minimal loss of data and time. Such software systems which can continue execution even in presence of faults are called fault tolerant software. When failure occurs one of the redundant software modules get executed and prevent system failure. The fault tolerant software systems are usually developed by integrating COTS (commercial off-the-shelf) software components. The motivation for using COTS components is that they will reduce overall system development costs and reduce development time. In this paper, reliability models for fault tolerant consensus recovery blocks are analyzed. In first optimization model, we formulate joint optimization problem in which reliability maximization of software system and execution time minimization for each function of software system are considered under budgetary constraint. In the second model the issue of compatibility among alternatives available for different modules, is discussed. Numerical illustrations are provided to demonstrate the developed models. © 2010 World Scientific Publishing Company. Source

Kashyap R.,Lal Bahadur Shastri Institute of Management | Vidyarthi D.P.,Jawaharlal Nehru University
Proceedings - 17th IEEE International Conference on Computational Science and Engineering, CSE 2014, Jointly with 13th IEEE International Conference on Ubiquitous Computing and Communications, IUCC 2014, 13th International Symposium on Pervasive Systems, Algorithms, and Networks, I-SPAN 2014 and 8th International Conference on Frontier of Computer Science and Technology, FCST 2014 | Year: 2015

Virtualization is critical to cloud computing because it simplifies the delivery of services by providing a platform for optimizing complex IT resources in a scalable manner. Virtualization architecture provides this illusion through hypervisors/Virtual Machine Monitor, which maps the physical resource to Virtual machines. Security is very essential for cloud users as they relinquish physical possession of their computation and data, which inevitably poses new security risks towards the confidentiality and integrity of the data. Lot of research is initiated in resource provisioning for hypervisors, but still many problems need to be addressed specially for security-aware and real time tasks. A dual objective scheduling algorithm, Real Time Security Maximization (RT-Smax), which aims to meet the deadline of the Virtual machines with best possible security is being proposed. Though this algorithm can be used by any hypervisor, for the current work it has been implemented on Xen VMM. Finally its effectiveness is validated by comparing it with Xen's credit scheduler on security demanding tasks having stringent deadline constraints. © 2014 IEEE. Source

Sahi G.,Lal Bahadur Shastri Institute of Management | Madan S.,University of Delhi
Communications in Computer and Information Science | Year: 2013

The current invigorated wave of E-commerce initiatives, post the initial boom and dot com bubble burst is definitely more prudent. Therefore, business community is looking to academe for understanding of how usability can be increased to reap the numerous benefits of E-commerce. This study has been undertaken in context of B2C E-commerce websites and its main purpose is to analyze the differential impact of web usability dimensions on perceived usefulness. This is done by studying customers' responses regarding B2C E-commerce websites with respect to four usability dimensions. A questionnaire survey is used to collect data from select respondents (N=415) and analysis is performed using structural equation modelling (SEM). Findings suggest that although all four dimensions significantly impact perceived usefulness, system quality followed by trust are the two most important factors. The study has important implications for website designers, developers and researchers. © Springer International Publishing Switzerland 2013. Source

Kashyap R.,Lal Bahadur Shastri Institute of Management | Vidyarthi D.P.,Jawaharlal Nehru University
IAENG International Journal of Computer Science | Year: 2012

The conflict between achieving good performance, in terms of time etc., and achieving high quality of security protection introduces new challenges in security critical grid scheduling. Extensive study indicates that the scheduling performance is affected by the heterogeneities of security and computational power of resources. Different jobs may have varied security requirement and even the same security requirement may exhibit different security overhead on different nodes. This paper proposes a GA based dual objective scheduling algorithm, Dual Objective Security Driven Scheduling using Genetic Algorithm (DO-SDSG). Maximization of security offered to tasks with minimization of security overhead are the two objectives of DO-SDSG. Being a dual objective scheduling problem, it alternatively optimizes the objectives. When one objective is optimized the other one is taken as a constraint and vice-versa. The simulation study demonstrates that the proposed algorithm delivers better makespan, better security with less security overhead in comparison to other such algorithms viz. MinMin, MaxMin, SPMinMin and SPMaxMin. Source

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