Erratum on “Optimal inventory control of empty containers in inland transportation system” [Int. J. Prod. Econ. 133(1) (2011) 451–457]

This paper points out some flaws in the simulation model presented by Yun et al. [2011. Optimal inventory control of empty containers in inland transportation system. International Journal of Production Economics 133 (1), 451–457]. Some of the formulae for inventory level and ordering quantity have errors which are corrected in this note.     

Errata to “A robust optimization model for stochastic logistic problems”: [International Journal of Production Economics, 64 (2000) 385–397]

This errata points out several errors in various optimization models and an inconsistent numerical result in Chian-Son Yu, Han-Lin Li [International Journal of Production Economics 64 (2000) 385–397].     

A centralized/decentralized design of a full return contract for a risk-free manufacturer and a risk-neutral retailer under partial information sharing: A discussion

This paper discusses some aspects of the centralised version of the supply chain coordination method that uses the so-called Alternating Direction Method (ADM) presented by Jeong (2012, A centralized/decentralized design of a full return contract for a risk-free manufacturer and a risk-neutral retailer under partial information sharing. International Journal of Production Economics 136 (1), 110–115). We show that the method requires both from the retailer and the manufacturer to faithfully follow the proposed algorithm, without any attempt to follow their own interests in gaining higher profits. We also warn that the condition of the information privacy is violated also in partial information sharing model. Furthermore, we correct an error in one of the equations.     

A note on “minimizing a weighted quadratic function of job lateness in the single machine system”

A set of jobs is to be scheduled on a single machine where an idle time is allowed to be inserted before the processing of the first job begins. The objective is to find an optimal sequence that minimizes the weighted sum of a quadratic function of job lateness. Sen et al. [Sen, T., Dileepan, P., Lind, M.R., 1995. Minimizing a weighted quadratic function of job lateness in the single machine system. International Journal of Production Economics 42(3), 237–243] presented a branch-and-bound algorithm for the problem; however, as shown in this note, their algorithm does not work because the branching rule for adjacent jobs is not applicable to non-adjacent jobs.     

An improved model for supplier selection under capacity constraint and multiple criteria

Ghodsypour and O'Brien [2001. The total cost of logistics in supplier selection, under conditions of multiple sourcing, multiple criteria and capacity constraint. International Journal of Production Economics 73(1), 15–27] study multiple sourcing problem with multiple criteria and capacitated suppliers. Considering the buyer's quality requirements as a constraint, they develop a mixed integer non-linear programming model to find the least-cost cyclic ordering policy for the buyer. They propose to solve the model by enumerating over all possible supplier combinations. Although the problem is interesting and their analysis is correct, we point out two issues with their assumptions, namely, capacitated suppliers and cyclic ordering policy. We discuss two different capacitated supplier settings: (i) long-run average annual capacity, and (ii) exact annual capacity. First, under long-run average annual capacity assumption we propose a model which provides the same or a better solution and is much easier to solve than their model. Then, we discuss how to modify our and their models to handle exact annual capacity assumption.     

A revised EMQ/JIT production-run model: An examination of inventory and production costs

Production-runs are an important cost minimizing scheduling and production planning activity. Commonly used classic lot-sizing models (i.e., economic manufacturing quantity or EMQ models) do not reflect current just-in-time (JIT) lot-sizing cost realities. The purpose of this paper is to present a cost comparison of the classic EMQ model and a revised EMQ/JIT model to show efficacy of a more cost inclusive model.     

The dynamics of just-in-time

This article analyses the impact of just-in-time production on the three resources of machines, materials and people, and suggests that JIT entails a redistribution of slack between these resources. The impact of JIT on an organization's human resources is particularly problematical; pressures towards both increased variety and intensity of work are apparent.     

Economic lot-sizing and dynamic quantity competition

We study a problem of dynamic quantity competition in continuous time with two competing retailers facing different replenishment cost structures. Retailer 1 faces fixed ordering costs and variable procurement costs and all inventory kept in stock is subject to holding costs. Retailer 2 only faces variable procurement costs. Both retailers are allowed to change their sales quantities dynamically over time. Following the structure of the economic order quantity (EOQ) model, retailer 1 places replenishment orders in batches and retailer 2 follows a just-in-time (JIT) policy. The objective of both retailers is to maximize their individual average profit anticipating the competitor's replenishment and output decisions. The problem is solved by a two-stage hierarchical optimization approach using backwards induction. The second-stage model is a differential game in output quantities between the two retailers for a given cycle length. At the first stage, the replenishment policy is determined. We prove the existence of a unique optimal solution and derive an open-loop Nash equilibrium. We show that both retailers follow contrary output strategies over the order cycle. The EOQ retailer, driven by inventory holding costs, decreases his market share whereas the output of the JIT retailer increases. Moreover, depending on the cost structure, the EOQ retailer might partially be a monopolist. At the first stage, the EOQ retailer determines the cycle length, anticipating the optimal output trajectories at the second stage.     

Application of fuzzy decision making in part-machine grouping

In this study, fuzzy set theory (FST) is used to set out the cell layout. A new algorithm which will consider both design and manufacturing attributes and operation sequences as factors, is proposed to formulate the problem. The structure of the algorithm is based on fuzzy decision making system (FDMS). Hence three factors mentioned above are determined as input variables and fuzzified using membership function concept. Then the pairwise comparison of the analytical hierarchy process (AHP), which ensures the consistency of the designer`s decisions when assigning the importance of one factor over another, is used to find the weights of these factors. Applying IF–THEN decision rules, parts relationship chart (PRC) is generated. After these steps, the traditional cell formation procedure is applied. Finally the proposed method is scored by performance measures such as machine investment, the amount of work load deviations within cell and between cells and the number of skippings. Also the comparison with Aktürk's study (International Journal of Production Research 34 (8) (1996) 2299–2315) in respect to these performance measures is presented.     

Approximation approach for the performance analysis of production lines under a kanban discipline

In a JIT production environment, pull-type control systems are usually implemented to reduce the lead time and to synchronize the production rate with the demand rate. The design of an effective production control system requires easy and reliable approaches for evaluating the effect of the major system parameters on its performance.In this paper we model the kanban control system of a manufacturing line as a Markov process. In addition, we develop an approximation approach to the model that permits reliable evaluation of manufacturing system performance in terms of throughput time and work-in-process. The validation of the approach is implemented by comparing the exact results (based on discrete event simulation) and the approximated results.A good approximation is observed for a large range of conditions.     

Organizational slack and firm performance during economic transitions: two studies from an emerging economy

An Erratum has been published for this article in Strategic Management Journal 25(3) 2004, 307. How does organizational slack affect firm performance? Organization theory posits that slack, despite its costs, has a positive impact on firm performance. In contrast, agency theory suggests that slack breeds inefficiency and inhibits performance. The empirical evidence, largely from developed economies, has been inconclusive. Moreover, little effort has been made to empirically test whether such an impact (positive or negative) is linear or curvilinear. This article joins the debate by extending empirical work to the largely unexplored context of economic transitions. Specifically, two studies, based on survey and archival data (N = 57 and 1532 firms, respectively), are undertaken in China's emerging economy. Our results suggest (1) that organization theory generates stronger predictions when dealing with unabsorbed slack, and (2) that agency theory yields stronger validity when focusing on absorbed slack. Furthermore, we also find that the impact of slack on performance is curvilinear, which resembles inverse U‐shaped curves. Overall, our findings call for a contingency perspective to specify the nature of slack when discussing its impact on firm performance. Copyright © 2003 John Wiley & Sons, Ltd.     

反行政性垄断与促进竞争政策研究新进展——“转轨经济中的反行政性垄断与促进竞争政策”国际研讨会观点综述

行政性垄断由于造成资源配置扭曲、社会福利损失、收入分配不均以及地方保护和区域市场分割等问题而日益成为社会各界关注的焦点。2007年11月19日在山东大学召开的“转轨经济中的反行政性垄断与促进竞争政策”国际研讨会对反行政性垄断的理论与政策问题进行了集中交流与探讨。本文介绍了与会专家学者对于该问题的主要学术观点．综述了反行政性垄断研究的新进展以及该领域亟待解决的理论和实践问题。     

A JIT lot-splitting model for supply chain management: Enhancing buyer–supplier linkage

This study develops a buyer–supplier coordination model to facilitate frequent deliveries in small lot sizes in a manufacturing supply chain. The proposed model, based on the integrated total relevant costs of both buyer and supplier, determines optimal order quantity, the number of deliveries/setups, and shipping quantity over a finite planning horizon in a relatively simple JIT single buyer single supplier scenario. Under deterministic conditions for a single product, we show that the optimal delivery policy adopted by both buyer and supplier in a cooperative manner can be economically beneficial to both parties. It is shown that the optimal delivery size can be unique, regardless of the order quantity and the number of deliveries. Numerical results are also presented.     

The Impact of Recent Gas Market Developments on Long-Term Projections for Global Gas Supply

Production from unconventional resources, increases in upstream development costs and sluggish demand growth have significantly impacted the global natural gas market in the recent past; and will likely continue to do so during the next decade. Taking these developments into account, we provide a projection of global natural gas supply until 2030 applying the MAGELAN world gas model by the Institute of Energy Economics at the University of Cologne (EWI). Apart from presenting the results of this simulation, the focus of this paper is thereby on the effects of recent supply, midstream and demand side trends on future gas supply compared to earlier studies and projections. While lower demand growth generally leads to relatively less international gas trade, pipeline exports are affected more strongly than trade in liquefied natural gas. In terms of gas output, this volume effect is found to mainly affect high cost gas producers at the upper end of the supply curve. Exports of suppliers with lower production costs and abundant reserves actually benefit.     

A Normalized Citation Analysis of Real Estate Journals

This study presents an analysis of the citation patterns and rankings for journals in real estate and related areas for the period 1990–1995. Journals were ranked based on the number of times they were cited in four base journals with adjustments for journal size and longevity. The results show that Real Estate Economics is the most cited journal among real estate publications, followed closely by the Journal of Real Estate Finance and Economics and the Journal of Real Estate Research . A temporal analysis reveals a shift in citations, over the time period, away from the traditional economics and practitioner-oriented journals to the academic real estate journals.     

“Squeezing R&D”: A Study of Organizational Slack and Knowledge Creation in NPD,Using the SECI Model

During new product development (NPD), functional areas such as marketing, R&D, and manufacturing work together to understand customer needs, create product concepts, and solve technical issues. NPD is dependent on the creation of new knowledge and the interplay between tacit knowledge (knowledge that is difficult to articulate and codify) and explicit knowledge (knowledge that can be codified and documented). Knowledge creation requires time and resources, and the dichotomy facing senior management is how much spare capacity in NPD teams—so‐called organizational slack—is appropriate. Too much organizational slack and precious development resources will be wasted; but when slack is eliminated, there is a danger that knowledge creation will be severely hindered. There have been very few studies of organizational slack at the project level, and so the aim of our research was to examine the impact of changes in organizational slack on knowledge creation in NPD projects. Six projects were studied at two companies, over a two‐year period. Multiple sources of data were used to determine how changes in organizational slack impacted knowledge creation, which was operationalized using Nonaka's socialization, externalization, combination, and internalization (SECI) model. It was found that the creation of knowledge in NPD projects is susceptible to changes in organizational slack. A significant finding was that every time there were changes in organizational slack, there was always some impact on knowledge creation. Increased slack enabled knowledge creation; but, importantly, the impacts of decreasing organizational slack were often very negative and disrupted the work of NPD teams, particularly at the end of projects. Managers who feel that “squeezing R&D” is important should think again—their action might disrupt knowledge creation and compromise innovation.     

Influential Journals, Institutions and Researchers in Real Estate

A threshold citation approach is used to measure the research influence of academic real estate journals, institutions and individual researchers. Real Estate Economics followed by The Journal of Real Estate Finance and Economics and Journal of Real Estate Research are the most influential real estate journals. Almost 63% of heavily cited works in core real estate journals are published in real estate journals. Twenty-one percent of the heavily cited works are published in Real Estate Economics . An overwhelming 80% of the citations of the 21 most heavily cited papers in real estate come from articles published in real estate journals. Even when real estate articles are published in top-tier finance and economics journals, the majority of the citations associated with these articles come from top real estate journals. This provides strong evidence of the existence of a distinct real estate research discipline. As compared to prior studies, an expanded universe of institutions is found to influence real estate research. Research-extensive universities generating high-quality economics, statistics and finance research influence the real estate discipline. The individuals that are most influential, however, are generally those with substantial real estate discipline specific research.     

Authors' Perceptions and Preferences Among Real Estate Journals

Journal editors who want to attract the best research must understand authors' perceptions of their journals. In this survey, U.S. academic authors rank Real Estate Economics ( REE ) higher than The Journal of Real Estate Finance and Economics ( JREFE ) and rank The Journal of Real Estate Research ( JRER ) third. Authors perceive REE as high quality with promotion and tenure value and JREFE as providing a fair, efficient publication process. Faculty at doctoral degree-granting schools are more discerning between the journals, whereas faculty at schools with real estate degree programs are more likely to have work in all three journals rewarded. Publishing in a journal and membership in a real estate association also influence opinions.     

The economic production quantity (EPQ) with shortage derived algebraically

Previously, in several papers and textbooks, the classical economic order quantity (EOQ) and the economic production quantity (EPQ) formulas for the shortage case, have been derived using differential calculus and solving two simultaneous equations (derived from setting the two first partial derivatives to zero) with the need to prove optimality conditions with second-order derivatives. In a previous original piece of work, a new approach to find the EOQ with backlogging using some slight algebraic developments appeared. This paper extends the mentioned algebraic approach to the EPQ formula taking shortages into consideration within the case of only one backlog cost per unit and time unit. The final expressions provide the same formulas that are available in the classic textbooks on inventory theory.     

Differentiation and alignment in KAM implementation

When key account management (KAM) programmes are created, they do not appear in a vacuum. Rather, they are developed in existing organizations and as a consequence the question arises of how to align the newly implemented KAM units within the host organizations. We propose using Lawrence and Lorsch's (1967a&b) differentiation concept and the concept of frame alignment (Goffman, 1974; Snow, Rochford, Worden, & Benford, 1986) to assess how much a KAM unit is actually differentiated and how to improve alignment. In a case study, we then describe the creation process of a KAM unit at Waters IS, a company specialising in water treatment. Based on a discussion of the theoretical concepts and the case situation, we suggest an approach to the assessment and management of alignment issues for KAM units.