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821 items in total found

Journal Articles | 2019

Design, modeling, and analysis of vertical robotic storage and retrieval systems

Debjit Roy, Kaveh Azadeh, and Rene De Koster

Transportation Science

Autonomous vehicle-based storage and retrieval systems are commonly used in many fulfillment centers (e.g., e-commerce warehouses), because they allow a high- and flexible-throughput capacity. In these systems, roaming robots transport loads between a storage location and a workstation. Two main variants exist: horizontal, where the robots only move horizontally and use lifts for vertical transport, and a new variant vertical, where the robots can also travel vertically in the rack. This paper builds a framework to analyze the performance of the vertical system and compare its throughput capacity with the horizontal system. We build closed queueing network models for this that, in turn, are used to optimize the design. The results show that the optimal height-to-width ratio of a vertical system is around one. Because a large number of system robots may lead to blocking and delays, we compare the effects of different robot blocking protocols on the system throughput: robot Recirculation and Wait-on-Spot. The Wait-on-Spot policy produces a higher system throughput when the number of robots in the system is small. However, for a large number of robots in the system, the Recirculation policy dominates the Wait-on-Spot policy. Finally, we compare the operational costs of the vertical and horizontal transport systems. For systems with one load/unload (L/U) point, the vertical system always produces a similar or higher system throughput with a lower operating cost compared with the horizontal system with a discrete lift. It also outperforms the horizontal system with a continuous lift in systems with two L/U points.

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Journal Articles | 2019

Robotized and automated warehouse systems: Review and recent developments

Kaveh Azadeh, Debjit Roy, and Rene De Koster

Transportation Science

Robotic handling systems are increasingly applied in distribution centers. They require little space, provide flexibility in managing varying demand requirements, and are able to work 24/7. This makes them particularly fit for e-commerce operations. This paper reviews new categories of automated and robotic handling systems, such as shuttle-based storage and retrieval systems, shuttle-based compact storage systems, and robotic mobile fulfillment systems. For each system, we categorize the literature in three groups: system analysis, design optimization, and operations planning and control. Our focus is to identify the research issue and operations research modeling methodology adopted to analyze the problem. We find that many new robotic systems and applications have hardly been studied in academic literature, despite their increasing use in practice. Because of unique system features (such as autonomous control, flexible layout, networked and dynamic operation), new models and methods are needed to address the design and operational control challenges for such systems, in particular, for the integration of subsystems. Integrated robotic warehouse systems will form the next category of warehouses. All vital warehouse design, planning, and control logic, such as methods to design layout, storage and order-picking system selection, storage slotting, order batching, picker routing, and picker to order assignment, will have to be revisited for new robotized warehouses.

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Journal Articles | 2019

Identifying defective network components through restricted group testing

Diptesh Ghosh

OPSEARCH

In this paper, we consider a network of switches in which some of the switches may malfunction. Our aim is to find out efficiently (a) if any of the switches in a network of switches are defective, and (b) if there are defective switches, to identify those switches. We find an optimal solution for the first problem and a heuristic solution to the second, and demonstrate the feasibility of our approach through computational experiments.

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Journal Articles | 2019

Strategizing in small informal retailers in India: Home delivery as a strategic practice

Atul Arun Pathak and George Kandathil

Asia Pacific Journal of Management

Small informally organized family-owned grocery retailers—kiranas—are ubiquitous in India and have retained market dominance while facing increasing competition from large formally organized retailers (FORs). Yet, strategy literature has under-explored such informal businesses. We explore kiranas’ distinct strategic practices that give them competitive advantage over FORs, generating kiranas’ sustained market dominance. To explore kiranas’ informal strategizing, grounded theoretic analysis of our multi-year case study suggested the employment of strategy as practice (SAP) framework, enriched with the social exchange theory (SET) concepts of trust and reciprocity. We find that the kiranas’ sustained enactment of strategic practice such as free-of-charge home-delivery significantly depends on contextually rich, reciprocity-based social exchange relationships with customers which evolve through praxes involving continuous exchange of trust. The practice enactment and exchange relationships constitute strategy-practitioner’s emerging dual-identity, which in turn reinforces the practices, generating a self-reinforcing cycle of practice enhancement. Within this cyclic relationship, an inimitable enactment of a strategic practice can be a key source of competitive advantage for informally organized small retail retailers over large FORs. By linking two unconnected prominent approaches to understanding patterns of workplace interactions, namely SAP and SET, the study opens theoretical avenues for exploring strategizing of informal businesses.

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Journal Articles | 2019

Non-optimality of state by state monopoly pricing with demand uncertainty: An example

James Peck and Jeevant Rampal

Economics Letters

This paper considers a monopoly’s profit maximizing problem, where there is a continuum of consumers with unit demand, and valuations are given by one of two possible demand distributions/states. The firm’s problem is to maximize profits by choosing an optimal mechanism among direct revelation mechanisms that satisfy interim incentive compatibility and ex-post individual rationality. We show that setting the monopoly price in each demand state may not be optimal.

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Journal Articles | 2019

An examination of factors driving big 4 audit fee premiums: Evidence from India's audit market

Joshy Jacob, Naman Desai, and Sobhesh Kumar Agarwalla

Accounting Horizons

This study examines fee premiums earned by Big 4 auditors in India and identifies the primary reason for such fee premiums. There are three primary drivers of Big 4 fee premiums. Big 4 auditors charge a fee premium for their reputation, for providing a superior quality of audit, and for indemnifying losses for a company's stakeholders. Since the risk of auditor litigation in India is relatively low, Big 4 premiums in India would not be driven by the need for auditors to indemnify losses. The results indicate that Big 4 auditors earn significantly higher fees in India and also that their clients enjoy significantly higher earnings response coefficients compared to non-Big 4 clients. However, there is no difference in the quality of audit provided by Big 4 and non-Big 4 auditors as measured by the magnitude of reported discretionary accruals.

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Journal Articles | 2019

Trust in humanitarian operations: a content analytic approach for an Indian NGO

Prakash Awasthy, K.V. Gopakumar, Sirish Kumar Gouda, and Tanushree Haldar

INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH

Trust between partners, a key element enabling coordination across supply chains, has recently started gaining attention in humanitarian operations literature. Yet, empirical examination of this concept is scant. Borrowing from extant literature on trust within organisational behaviour stream, this paper aims to empirically verify trust formation types: companion, competence and commitment, in a disaster relief supply chain using primary and secondary data from an Indian Humanitarian relief organisation (HRO). Further, we identify variations in trust formation during disaster relief activities and developmental programmes, and between upstream and downstream partners of a humanitarian relief organisation. Based on the results of our content analysis, we contend that while companion based trust is significantly more prevalent during developmental programmes, competence based trust is important during both disaster periods and otherwise. We also find that there are significant differences in the trust formation between upstream and downstream partners and the HRO. This study has significant theoretical and practical implications on identifying the role of trust in humanitarian operations.

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Journal Articles | 2019

What drives human resource acquisition and retention in social enterprises? An empirical investigation in the healthcare industry in an emerging market

Aditya Moses and Amalesh Sharma

Journal of Business Research

Although healthcare is one of the fastest growing sectors in the world, it faces crucial shortages in human resource (HR) availability and retention. This challenge is worsened in social enterprises. In this research, we build on a multimethod and a multistudy approach. In the first study, using an exploratory qualitative study, we identify HR practices that influence HR acquisition and retention. Utilizing an institutional logics lens, we propose that market logic and community logic-driven HR practices influence a firm's ability to acquire and retain HR. In the second study, we test our hypotheses using primary data from 182 faith-based hospitals in India and a robust empirical model accounting for endogeneity. We find that while market logic-driven HR practices help with HR acquisition, community logic-driven HR practices help with HR retention. In the third study, through a simple field experiment, we showcase that, indeed, market and community logic-based HR practices are responsible for HR acquisition and retention.

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Journal Articles | 2019

Women's political leadership and economic empowerment: Evidence from public works in India

Klaus Deininger, Hari K Nagarajan, and Sudhir K Singh

Journal of Comparative Economics

Despite recent advances, women trail men in political participation, especially in developing countries where the long-term economic benefits from empowering women politically have not been well-researched. We use data from 163 villages of 12 main Indian states to explore whether requiring that village leadership positions be held by women (political reservation) affected uptake of economic opportunities via the National Rural Employment Guarantee Scheme. Reservation triggered increases in women's demand for work, program participation, and access to financial services that were sustained beyond the period of female political leadership. Enhanced female participation in program oversight, civic engagement, and electoral participation are plausible channels for such effects and political and economic empowerment seem to be complementary.

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Journal Articles | 2019

Jati, local public goods and village governance: Private actions and public outcomes

Raghbendra Jha, Hari K Nagarajan, and Anirudh Tagat

Economic & Political Weekly

Whether voting along narrow parochial lines in socially and ethnically fragmented societies has measurable gains is explored. Using data from rural India, it is established that identity-based voting, driven by membership in social and informal networks, will lead to enhanced participation in welfare programmes, which in turn leads to increased consumption growth. Further, reducing agency costs does not necessarily remove the need for identity-based voting, and such voting behaviour is a means for engaging in the capture of public and private benefits by these groups.

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