Showing papers by "Indian Institute of Management Calcutta published in 2006"

“Optimization of aircraft maintenance/support infrastructure using genetic algorithms—level of repair analysis”

Abstract: Level of repair analysis (LORA) is an approach used during the design stage of complex equipment for analysis of the cost effectiveness of competing maintenance strategies. LORA is carried as a part of the life cycle cost and cost of ownership analysis and plays a significant role in minimizing the life cycle cost and cost of ownership of the capital equipment. Since many purchasing decisions of complex equipment are based on cost of ownership, it has become essential to carry out LORA to compete in the market. In this paper, we develop a mathematical model for LORA and propose a solution methodology based on genetic algorithms. The concept is illustrated using a hypothetical aircraft engine.

A survey of tcp enhancements for last-hop wireless networks

Abstract: TCP continues to be an important transport-layer communication protocol that is typically tuned to perform well in traditional wired networks, where bit error rate (BER) is low and congestion is the primary cause of packet loss. The emergence of various mobile access networks has prompted researchers to look for suitable modifications to TCP so as to make it survive in the wireless era as well. Networks with wireless links and mobile hosts incur significant losses due to high BER, host motion, and handoff mechanisms. Mobile devices face temporary and unannounced loss of network connectivity when they move. They are likely to have scarce resources, and they react to frequent changes in the environment. Motion causes varying, increased delays and packet losses, while the network learns how to deliver packets to the new location of the host. TCP incorrectly interprets these delays and losses as signs of network congestion and throttles its transmission rate, causing degraded end-to-end performance. This article provides an in-depth survey of various TCP enhancements which are specifically targeted for last-hop wireless environments. The objective is to review the performance issues of TCP variations, when employed in last-hop wireless networks, and to provide a categorized analysis of different existing solutions comparatively, as we all know that it is difficult to create a “one size fits all” TCP for last-hop wireless networks.

Executive Compensation, Firm Performance and Corporate Governance: An Empirical Analysis

Abstract: This paper investigates the determinants of executive compensation using the most recent data on firm performance, corporate governance and managerial compensation for a large sample of Indian firms. A linear regression model is used to develop explanations for total CEO compensation and the proportion of incentive pay that forms a part of the CEO's compensation. It is found that firm size is a significant determinant of both these aspects of CEO compensation. The results also show that CEOs who are promoters of their firms earn significantly more than ordinary CEOs. Such individuals also earn a much larger component of their compensation as incentive pay. In addition, this study also quantifies the significant divergences in compensation policies that are followed at firms in the public sector when compared to private sector firms.

e-Risk Management with Insurance: A Framework Using Copula Aided Bayesian Belief Networks

Abstract: e-business organizations are heavily dependent on distributed 24X7 robust information computing systems, for their daily operations. To secure distributed online transactions, they spend millions of dollars on firewalls, anti-virus, intrusion detection systems, digital signature and encryption. Nonetheless, a new virus or a clever hacker can easily compromise these deterrents, resulting in losses to the tune of millions of dollars annually. To cope up with the problem, in this work we propose to further enhance their security management by investing in e-risk insurance products as a viable alternative to reduce these individual financial losses. We develop a framework, based on copula aided Bayesian Belief Network (BBN) model, to quantify the risk associated with online business transactions, arising out of a security breach, and thereby help in designing e-insurance products. We have simulated marginal data for each BBN nodes. The Copula model helps in arriving at the joint probability distributions from these marginal data. From the joint distribution data, we arrive at the conditional distribution tables for each node. This is input to the Bayesian Belief Network model. The output is frequency of occurrence of an e-risk event. Frequency of loss multiplied with the expected loss amount, provides the risk premium to be charged by insurance companies.

Enhancing the Performance of Ad Hoc Wireless Networks with Smart Antennas

Abstract: A large portion of the network capacity of an ad hoc network can be wasted by the medium access mechanisms of omni-directional antennas. To overcome this problem, researchers propose the use of directional or adaptive antennas that largely reduce radio interference, improving the utilization of wireless medium and the resulting network throughput.<

A Person–Organization Fit-based Approach for Spirituality at Work: Development of a Conceptual Framework

Abstract: Management of meaning inside organizations has been an enduring issue in organization studies. Issues relating to commitment and control through the meaning-making mechanisms have been studied by organization culture theorists for sometime now. However, rapidly changing dynamics of the business environment lend these issues a critical salience today. Two factors of this dynamic context are particularly noteworthy. Firstly, a redefinition of the long-standing employment relationship—loyalty no longer being traded for lifelong employment—has led management to look for alternative sources of gaining commitment from their employees. Second, several factors—socio-cultural, organizational and individual—have led the employees today to explore issues relating to meaning and purpose in their workplaces. Labelled variously by different scholars, the most widely accepted term for this growing movement is ‘Spirituality at Work’ (SAW). In this article we link the two factors to present a framework wherein the emergen...

Networking and New Venture Resource Strategies A Study of Information Technology Start-ups

Abstract: While the network theory and the resource-based view of the firm has emerged as a dominant paradigm of management research, entrepreneurship researchers continue to show limited interest in studying resource strategies and the role of network in building dynamic capabilities in entrepreneurial start-ups. Scant discussion is available in extant literature on the dynamics of new venture resource strategy to explain how entrepreneurs continuously augment, manage and develop resources to match the shifting product-market strategy and use networks in doing so on a sustainable basis. This article, based on an analysis of two Information Technology (IT) start-ups, explores the innovative and dynamic resource and networking strategies such firms follow. An attempt has been made to conceptualise and explain how these firms maintain flexibility in resources by using the network mode of organisation in order to avoid strategic rigidity and craft strategies that are suited to the high velocity environment. Several pr...

A cost model for N-version programming with imperfect debugging

Abstract: One of the challenging problems for software companies is to find the optimal time of release of the software so as to minimize the total cost expended on testing and potential penalty cost due to unresolved faults If the software is for a safety critical system, then the software release time becomes more important The criticality of a failure caused by a fault also becomes an important issue for safety critical software In this paper we develop a total cost model based on criticality of the fault and cost of its occurrence during different phases of development for N-version programming scheme, a popular fault-tolerant architecture The mathematical model is developed using the reliability growth model based on the non-homogeneous Poisson process The models for optimal release time under different constraints are developed under the assumption that the debugging is imperfect and there is a penalty for late release of the software The concept of Failure Mode Effects and Criticality Analysis is used for measuring criticality

Information systems assimilation in Indian organizations: An examination of strategic and organizational imperatives

Abstract: IT investment by organizations in India has increased significantly over the last 10 years, as Indian firms have deployed IS for modernizing and reengineering their processes. This paper analyzes, in an exploratory vein, organizational and strategic imperatives that have influenced IS assimilation and evolution of the IS application portfolio in Indian firms. It first identifies three categories of organizations with respect to IS assimilation, and describes strategic and organizational factors characteristic of each group. Next, it traces the evolution of the IS application portfolio in each of the studied firms and analyses accompanying changes in strategic and organizational factors. The paper builds on IS assimilation studies in organizations from developed societies, and describes issues unique to IS assimilation in Indian firms. It is based on data collected from case studies of IS deployment in nine Indian organizations.

D-optimal designs for covariate models

Abstract: The problem of finding D-optimal or D-efficient designs in the presence of covariates is considered under a completely randomized design set-up with v treatments, k covariates and N experimental units. In contrast to Lopes Troya [Lopes Troya, J., 1982, Optimal designs for covariates models. Journal of Statistical Planning and Inference, 6, 373–419.], who considered this problem in the equireplicate case, we do not assume that N/v is an integer, and this allows us to study situations where no equireplicate design exists. Even when N/v is an integer, it is seen quite counter-intuitively that there are situations where a non-equireplicate design outperforms the best equireplicate design under the D-criterion.

Corporate Codes of Conduct in India A Survey

Abstract: Codes of conduct play an important role in a corporation's effort to institutionalize ethics. The imperative of their implementation and compliance has been widely recognized by corporations across the world. Given this backdrop, a survey has been conducted in India to ascertain: (a) how many corporations have codes of conduct; ( b) whether common ethical issues/themes exist among them; (c) whether they have proper ‘ethics management systems’ in place; and (d) whether codes of conduct reflect any distinctive national character. This article reports the findings of the survey based on content analysis and offers suggestions as to how corporations can make their code an ‘ideal code’ and also scope for further research.

Optimal (2, n) visual cryptographic schemes

Abstract: In (2,n) visual cryptographic schemes, a secret image(text or picture) is encrypted into n shares, which are distributed among n participants. The image cannot be decoded from any single share but any two participants can together decode it visually, without using any complex decoding mechanism. In this paper, we introduce three meaningful optimality criteria for evaluating different schemes and show that some classes of combinatorial designs, such as BIB designs, PBIB designs and regular graph designs, can yield a large number of black and white (2,n) schemes that are optimal with respect to all these criteria. For a practically useful range of n, we also obtain optimal schemes with the smallest possible pixel expansion.

Three-stage and accelerated sequential point estimation of the normal mean using LINEX loss function

Abstract: Consider a normal population with unknown mean μ and unknown variance σ2. We estimate μ under an asymmetric LINEX loss function such that the associated risk is bounded from above by a known quantity w. This necessitates the use of a random number (N) of observations. Under a fairly broad set of assumptions on N, we derive the asymptotic second-order expansion of the associated risk function. Some examples have been included involving accelerated sequential and three-stage sampling techniques. Performance comparisons of these procedures are considered using a Monte-Carlo study.

Managing Customer Service Levels and Sustainable Growth: A Model for Decision Support

Abstract: Managing service levels is known to be an important element of customer relationship management. In service industries however, there is no inventory of finished goods that can be used to buffer production and yet maintain superior service levels in the face of uncertain demand patterns. Hence capacity planning for different resources takes on special importance in achieving high customer service levels. In this paper, we focus on the human resource element in a generic service firm. Using the system dynamics methodology, we develop a model of workforce acquisition and training that is driven by target levels of customer service and customer base. The model reveals the significant effects of natural process delays on maintaining service levels, and we demonstrate how it can serve as a decision support tool to achieve growth in the customer base while maintaining service levels. Such analysis can contribute to the collection of activities needed to conduct customer relationship management.

ACR: an adaptive communication‐aware routing through maximally zone‐disjoint shortest paths in ad hoc wireless networks with directional antenna

Abstract: A fundamental problem that distinguishes wireless networks from wired networks is the mutual interference between routes within the proximity of each other. This phenomenon is known as route coupling and it restricts the possibility of occurrence of simultaneous communications along the coupled routes. In this context, the use of directional antenna, having smaller transmission beam-width compared to omni-directional antenna, helps to easily decouple interfering routes, and improves network performance through space division multiple access (SDMA). However, even if we have an efficient directional MAC protocol, it alone would not be able to guarantee good system performance, unless we have a proper routing strategy in place that exploits the advantages of directional antenna. So, in this paper, an adaptive routing strategy is proposed that exploits the advantages of directional antenna in ad hoc networks through the selection of maximally zone-disjoint shortest routes. Zone-disjoint routes would minimize the effect of route coupling and improve the overall network performance. The proposed strategy ensures effective load balancing and is applied to design and implement both single path and multipath routing protocols in ad hoc networks with directional antennas. Simulation results obtained on QualNet network simulator shows the effectiveness of the proposed routing protocols. Copyright © 2006 John Wiley & Sons, Ltd.

A novel version of Wireless TCP for Vehicular On-Board IP Networks

Abstract: Network Mobility (NeMo) arises when a mobile router connecting a network to the Internet dynamically changes its point of attachment. By taking advantage of this kind of network mobility, Internet services can be extended to users traveling in public transport vehicles having high speed LANs deployed on-board. On-board LANs connect to the Internet via mobile router. Here, two primary issues viz. mobility of the network as a hole and existence of multiple wireless links, give rise to several unique challenges for achieving a high end-to-end TCP throughput. In this paper we propose an approximately modified version of TCP Snoop, called on-board TCP (obTCP) for vehicular On-Board IP Networks. Its central concern is to shield the sender from non-congestion related losses without changing existing TCP implementation at the end hosts. We have evaluated the performance of obTCP in ns-2 simulator and compared with TCP Snoop.

Persistence in Performance of Indian Equity Mutual Funds: An Empirical Investigation

Abstract: Persistence in performance of fund managers has been a topic of interest among finance fraternity for the last four decades. In this paper we evaluated the relative performance of equity mutual funds in India with respect to three performance indicators, and also tested the persistence in their performance with respect to these indicators across time. The performance indicators used for the funds are their raw returns, the tracking error they generate over their benchmarks, and the information ratios they attain. We find that on the whole the funds have done well. Their overall average return, tracking error and information ratio is positive during our study period. For the persistence part, we used a regression approach and a contingency table approach which showed no evidence of persistence for the ELSS funds, and some evidence of persistence for the Growth funds or all funds taken together. Our results were further substantiated with a Spearman Rank Correlation test. Another interesting finding is that evidence of persistence is more apparent over a one year evaluation horizon, compared to a time horizon either less than or more than one year. In fact persistence disappears completely when the horizon is extended to a period of time as long as thirty months or more. This gives the impression of efficiency of the market in the long run. Persistence seems to be marginally more for raw returns compared to that of tracking error or information ratio. On the whole it seems that past performance is hardly a reliable guide for future performance, particularly over a longer time horizon.

A Routing and Wavelength Assignment (RWA) Technique to Minimize the Number of SONET ADMs in WDM Rings

Abstract: WDM networks are increasingly gaining popularity as the backbone networks all over the world. In WDM network planning, electronic equipments like ADMs contribute heavily towards the capital expenditure of the network (Each ADM costs $50,000-$200,000). In WDM rings, determining minimum number of ADMs is NP-Hard. All the previous works have focused on Wavelength Assignment problem by keeping the routing fixed. In this paper, we suggest an integrated topology independent procedure called M3AWI (Minimum Average Minimum Weight Minimum Intersection). M3AWI is used to solve problems on four different types of routing namely, clockwise routing, Anti-clockwise routing, shortest-path routing, and hybrid routing. Our experimental results show that the combined Routing and Wavelength assignment (RWA) algorithms on an average save around 10% of the ADMs.We have also shown that the distribution of lightpaths is an important parameter to the service providers for selecting a routing policy.

An Efficient Algorithm for Real-Time Frequent Pattern Mining for Real-Time Business Intelligence Analytics

Abstract: Finding frequent patterns from databases has been the most time consuming process in data mining tasks, like association rule mining. Frequent pattern mining in real-time is of increasing thrust in many business applications such as e-commerce, recommender systems, and supply-chain management and group decision support systems, to name a few. A plethora of efficient algorithms have been proposed till date, among which, vertical mining algorithms have been found to be very effective, usually outperforming the horizontal ones. However, with dense datasets, the performances of these algorithms significantly degrade. Moreover, these algorithms are not suited to respond to the real-time need. In this paper, we describe BDFS(b)-diff-sets, an algorithm to perform real-time frequent pattern mining using diff-sets and limited computing resources. Empirical evaluations show that our algorithm can make a fair estimation of the probable frequent patterns and reaches some of the longest frequent patterns much faster than the existing algorithms.

Direction and Communication-Aware Directional Mac Protocol in Ad Hoc Networks Using Directional Antenna

Abstract: Our major contribution in this paper is to devise a MAC protocol that exploits the advantages of directional antenna in ad hoc networks for improved system performance. In order to implement effective MAC protocol in this context, a node should know how to set its transmission direction to transmit a packet to its neighbors and to avoid transmission in other directions where data communications are already in progress. In this paper, we are proposing a receiver-centric approach for Direction and Communication-Aware MAC (DCA-MAC) protocol, so that, nodes become aware of its neighborhood and also the direction of the nodes for communicating directionally. Our proposed directional MAC protocol can be effective in both ITS (Intelligent Transportation System), which we simulate in String and Parallel Topology, and in any community network, which we simulate in Random Topology. The performance evaluation on QualNet network simulator clearly indicates the efficiency of our protocol. In addition, under the fading channel conditions, it?s difficult for each node to perceive the status of the neighbors. In AWGN, Ricean and fading environments, we compare and analyze the performance of omnidirectional MAC, conventional directional MAC and our proposed directional MAC.

Strategic change of firms in response to economic liberalisation in an emerging market economy

Abstract: This paper presents an analysis of how policy induced changes in the institutional environment in India, a big emerging market undergoing economic liberalisation, have influenced strategic behaviour of firms. An exploratory multivariate model is empirically fitted using LISREL. Results suggest that environment was to be the most dominant exogenous factor influencing corporate strategy and performance of firms. However, firms having better environment-strategyfit' achieved superior performance. Initial resource position seems to have limited influence on strategy and performance. The results also suggest that increased their scale of business and diversified into deregulated industries selectively but aggressively achieved superior performance.

A one-pass method of MIP registration by WLAN host through GPRS network

Abstract: This paper proposes a new technique for Mobile IP (MIP) registration by WLAN host (WH) through GPRS network. The home agent (HA) of WH resides in external IP network. The gateway GPRS support node (GGSN) provides foreign agent (FA) functionality for WH in GPRS. After successful attach with GPRS network, WH needs two mandatory passes for MIP registration with HA. First it establishes PDP (packet data protocol) context in GPRS network and then it sends MIP registration request (MRR) to FA at GGSN. This causes a large delay for handoff from WLAN to GPRS. We propose a one-pass technique of MIP registration through GPRS network to reduce the handoff delay. We transport MIP-registration request of WH in the information field of activate-PDP-context request message to GGSN. Thus MIP registration message reaches GGSN before completion of PDP context establishment. This technique reduces the control signaling for handoff from WLAN to GPRS. We observed from simulated results that proposed one-pass technique reduces handoff delay by 18% compared to handoff delay in two-pass method.

An Efficient Heuristic Search for Real-Time Frequent Pattern Mining

Abstract: Real-time frequent pattern mining for business intelligence systems are currently in the focal area of research. In a number of areas of doing business, especially in the arena of supply chain management systems, real-time frequent pattern mining is in need. The need is being felt more due to the possibility of real-time knowledge discovery along with the gradual acceptance of technologies like RFID and grid computing and the huge amount of possibilities they promise for real-time decision making like supply-chain optimization. In this paper, we describe a domain-independent heuristic, h1-max and a heuristic search algorithm, BDFS(b)-h1-max for real-time frequent pattern mining, even using limited computer memory. Empirical evaluations show that the techniques being presented can make a fair estimation of the set of the probable frequent patterns and completes the search much faster than the existing algorithms.

Integrated inventory model for similar products under a two-echelon supply chain environment: An empirical study

Abstract: In this paper we have considered a two echelon supply chain that handles multiple products under stochastic demand. Retailer sells products to customers and manufacturer produces it on a shared resource with limited capacity. Product changeovers incur significant setup cost and setup time. The objective is to find the production batch size, the stock to be held at the retailer, and the point at which the item should be taken up for production such that the total cost for the entire supply chain is minimized. We have come up with an analytical model for the case where all the products are similar. This model is tested on a wide range of problems and the comparison with simulation show promising results. This would be useful in formulating simple rules of inventory management at retailer and manufacturer, when the products under consideration are relatively similar.

Multiobjective Genetic Algorithm for k-way Equipartitioning of a Point Set with Application to CAD-VLSI

Abstract: Buffered clock-tree design, with cells at its leaves, are known to meet timing and skew requirements better. Clustering of flip-flops leads to reduced clock-tree wirelengths and power-efficient layouts. In this paper, the problem of clustering flip-flops in a given placement is formulated as Multi-way Equi-Partitioning of a given point set, such that (i) total area of the partition (ii) area of the largest partition and (iii) total deviation of the partitions, are minimal. For this computationally expensive multiobjective optimization problem, also relevant to design of semi-synchronous systems, a technique based on genetic algorithm, is proposed. Crossover and mutation operators specific to the k-way equipartitioning problem, have been designed and a new greedy heuristic operator is employed to accelerate the convergence. Results on data sets obtained from layouts of ISCAS89 benchmark circuit demonstrate the effectiveness of the proposed method.