O(m2) ALGORITHMS FOR THE TWO AND THREE SUBLOT LOT STREAMING PROBLEM

Lot streaming is the process of splitting a job or lot into sublots to reduce its makespan on a sequence of machines. The goal in the lot streaming problem is to find the optimal size of each sublot that will minimize the makespan. The makespan is defined as the time the last sublot completes its processing on the last machine. If the sizes of these sublots are restricted to remain the same on all machines, the solution is called a consistent sublot solution. However, if the sizes of the sublots are allowed to vary, the solution is referred to as a nonconsistent or variable sublot solution. Also, if the machines must be in operation continuously from the first to the last sublot, the solution is a no idling solution. When setups are explicitly considered in the problem, there will be two cases. If setups on each machine require some portion of the first sublot be present by the machine, the problem is referred to as the attached setup time problem. If setups can be performed ahead of time before the first sublot reaches the particular machine, the corresponding problem is referred to as the detached setup problem. Finally, if the machines are allowed to be idle between the processing of sublots, the resultant solution is an intermittent idling solution. In this paper, the consistent sublot lot streaming problem with intermittent idling and no setups is discussed. The models developed also assume that the number of sublots are fixed and known. The m machine two sublot lot streaming problem is reviewed. An algorithm for the three sublot, m machine problem is derived using a network representation of the problem. The complexity of the algorithm is O (m²). Finally, using the insights from three sublot problem, a heuristic algorithm is provided for the m machine, n sublot problems. The results on the proposed heuristic are very encouraging; average percent deviation from optimal makespan is approximately at 0.76% on 155 randomly generated problems with different m and n values.     

A hybrid genetic algorithm/mathematical programming approach to the multi-family flowshop scheduling problem with lot streaming

This paper presents a hybrid genetic algorithm/mathematical programming heuristic for the n-job, m-machine flowshop problems with lot streaming. The number of sublots for each job and the size of sublots are directly addressed by the heuristic and setups may be sequence-dependent. A new aspect of the problem, the interleaving of sublots from different jobs in the processing sequence, is developed and addressed. Computational results from 12 randomly generated test sets of 24 problems each are presented.     

Optimal and Heuristic Models for Lot Splitting in a Flow Shop

This paper investigates optimal lot-splitting policies in a multiprocess flow shop environment with the objective of minimizing either mean flow time or makespan. Using a quadratic programming approach to the mean flow time problem, we determine the optimal way of splitting a job into smaller sublots under various setup times to run time ratios, number of machines in the flow shop, and number of allowed sublots. Our results come from a deterministic flow shop environment, but also provide insights into the repetitive lots scheme using equal lot splits for job shop scheduling in a stochastic environment. We indicate those conditions in which managers should implement the repetitive lots scheme and where other lot-splitting schemes should work better.     

Optimal Solutions for the Single Batch,Flow Shop,Lot‐streaming Problem with Equal Sublots

Lot streaming is the process of splitting a production lot into sublots and then scheduling the sublots in overlapping fashion on the machines in order to improve the performance of the production system. Implementation of this concept arises in several batch production environments. These include, among others, printed circuit board assembly and semiconductor fabrication. There are several limitations in the lot‐streaming models available in the literature which affect their usefulness in reality. In this paper, we consider the single batch, flow shop, lot‐streaming problem but relax several of these limitations. The main contribution of this paper is to provide the production manager with a way of splitting a lot in order to optimize performance under various measures of performance and setup time considerations. In addition, the insight of the proposed procedure can be used to tackle more general versions of the problem considered.     

基于批量流的多阶段生产系统的优化问题研究

考虑一个多阶段生产系统,在每个阶段上生产批量被分成若干个子批量进行加工,子批量可以相等也可以不相等,同时每个阶段上在相邻子批量之间可以有空闲。每个阶段上子批量的数目可以不相等。文中首先以系统总变动成本为目标函数对这样一个系统建立对应的模型,提出了求解这一问题的启发式方法,通过数值算例验证了这一方法的有效性。此外,还讨论了重启成本、空闲成本和对应于子批量的调整成本对系统总变动成本、生产批量以及子批量数目的影响。     

Complexity analysis for maximum flow problems with arc reversals

We provide a comprehensive study on network flow problems with arc reversal capabilities. The problem is to identify the arcs to be reversed in order to achieve a maximum flow from source(s) to sink(s). The problem finds its applications in emergency transportation management, where the lanes of a road network could be reversed to enable flow in the opposite direction. We study several network flow problems with the arc reversal capability and discuss their complexity. More specifically, we discuss the polynomial time algorithms for the maximum dynamic flow problem with arc reversal capability having a single source and a single sink, and for the maximum (static) flow problem. The presented algorithms are based on graph transformations and reductions to polynomially solvable flow problems. In addition, we show that the quickest transshipment problem with arc reversal capability and the problem of minimizing the total cost resulting from arc switching costs are NP\mathcal{NP} -hard.     

Estimating Derivatives in Nonseparable Models With Limited Dependent Variables

We present a simple way to estimate the effects of changes in a vector of observable variables X on a limited dependent variable Y when Y is a general nonseparable function of X and unobservables, and X is independent of the unobservables. We treat models in which Y is censored from above, below, or both. The basic idea is to first estimate the derivative of the conditional mean of Y given X at x with respect to x on the uncensored sample without correcting for the effect of x on the censored population. We then correct the derivative for the effects of the selection bias. We discuss nonparametric and semiparametric estimators for the derivative. We also discuss the cases of discrete regressors and of endogenous regressors in both cross section and panel data contexts.     

A near-optimal heuristic for the sequencing problem in multiple-batch flow-shops with small equal sublots

In this paper, we consider the lot-streaming problem of sequencing a set of batches, to be processed in equal sublots, in a flow-shop, so as to minimize makespan. A new heuristic procedure, called the bottleneck minimal idleness heuristic, is developed. Results of an experimental study are presented. It is shown that the proposed procedure generates solutions that are very close to the optimal solutions, and that the solutions generated are better than those obtained by using the fast insertion heuristic, considered to be a good heuristic for solving the flow-shop scheduling problem, when applied to the problem on hand.     

10 Sociomateriality: Challenging the Separation of Technology,Work and Organization

Abstract

We begin by juxtaposing the pervasive presence of technology in organizational work with its absence from the organization studies literature. Our analysis of four leading journals in the field confirms that over 95% of the articles published in top management research outlets do not take into account the role of technology in organizational life. We then examine the research that has been done on technology, and categorize this literature into two research streams according to their view of technology: discrete entities or mutually dependent ensembles. For each stream, we discuss three existing reviews spanning the last three decades of scholarship to highlight that while there have been many studies and approaches to studying organizational interactions and implications of technology, empirical research has produced mixed and often‐conflicting results. Going forward, we suggest that further work is needed to theorize the fusion of technology and work in organizations, and that additional perspectives are needed to add to the palette of concepts in use. To this end, we identify a promising emerging genre of research that we refer to under the umbrella term: sociomateriality. Research framed according to the tenets of a sociomaterial approach challenges the deeply taken‐for‐granted assumption that technology, work, and organizations should be conceptualized separately, and advances the view that there is an inherent inseparability between the technical and the social. We discuss the intellectual motivation for proposing a sociomaterial research approach and point to some common themes evident in recent studies. We conclude by suggesting that a reconsideration of conventional views of technology may help us more effectively study and understand the multiple, emergent, and dynamic sociomaterial configurations that constitute contemporary organizational practices.     

The War of the Woods: Facilitators and Impediments of Organizational Learning Processes

This study examines unfolding organizational learning processes at MacMillan Bloedel, a company which, after years of resisting stakeholder pressures for change, disengaged from the field’s dominant paradigm and developed a new solution. We elaborate the Crossan, Lane and White multi–level framework of organizational learning processes, finding support for the four feedforward learning processes they identified (intuiting, interpreting, integrating and institutionalizing), and adding two action–based learning processes: ‘attending’ and ‘experimenting’. We introduce the concept of a ‘legitimacy trap’ to describe an organization’s over–reliance on institutionalized knowledge when external challenges arise. The trapped organization rejects external challenges of its legitimacy when it perceives the sources of those challenges to be illegitimate. Feedforward learning is blocked as the organization escalates its commitment to its institutionalized interpretations and actions. Taking a grounded theory approach, we discuss how individuals attend to new stimuli and engage in intuiting about them, how groups interpret, experiment with and integrate new solutions, and how the firm validates and institutionalizes the successful solution. Facilitators and impediments of each of these learning processes are identified. Our additions to the model recognize the importance of context in organizational learning processes, and suggest how power may impact organizational learning.     

Incrementing Bipartite Digraph Edge-Connectivity

This paper solves the problem of increasing the edge-connectivity of a bipartite digraph by adding the smallest number of new edges that preserve bipartiteness. A natural application arises when we wish to reinforce a 2-dimensional square grid framework with cables. We actually solve the more general problem of covering a crossing family of sets with the smallest number of directed edges, where each new edge must join the blocks of a given bipartition of the elements. The smallest number of new edges is given by a min-max formula that has six infinite families of exceptional cases. We discuss a problem on network flows whose solution has a similar formula with three infinite families of exceptional cases. We also discuss a problem on arborescences whose solution has five infinite families of exceptions. We give an algorithm that increases the edge-connectivity of a bipartite digraph in the same time as the best-known algorithm for the problem without the bipartite constraint: O(km log n) for unweighted digraphs and O(nm log (n ²/m)) for weighted digraphs, where n, m and k are the number of vertices and edges of the given graph and the target connectivity, respectively.     

A Branch and Cut solver for the maximum stable set problem

This paper deals with the cutting-plane approach to the maximum stable set problem. We provide theoretical results regarding the facet-defining property of inequalities obtained by a known project-and-lift-style separation method called edge-projection, and its variants. An implementation of a Branch and Cut algorithm is described, which uses edge-projection and two other separation tools which have been discussed for other problems: local cuts (pioneered by Applegate, Bixby, Chvátal and Cook) and mod-k cuts. We compare the performance of this approach to another one by Rossi and Smiriglio (Oper. Res. Lett. 28:63–74, 2001) and discuss the value of the tools we have tested.     

Specters,Inc.: The Elusive Basis of the Corporation

In this article we discuss the political and economic consequences of the contemporary legal theory of incorporation. We argue that incorporation has developed historically in a way that makes it internally inconsistent, but that this inconsistency is useful for the powerful because of its legal and economic effects. The corporation can “shape shift,” which is very helpful for claiming some rights and disavowing certain responsibilities. Of course this flexibility comes at the expense of consistent concepts and this leads to the creation of what we term an “ideal‐type reified singular representation.” We go on to show the far‐reaching effects of this representation for legal studies, economics, and political theory, and show it worked in the pro‐corporate decision in the recent Citizens United case. We conclude by providing several alternative ways to think about the nature of corporate organization.     

A Retrospective Look at Production and Operations Management Articles on New Product Development

We present a retrospective look at the articles on New Product Development that appeared in the first 50 issues of Production and Operations Management (POM). We discuss some of the strengths and weaknesses of this POM literature stream. This article is not intended to be a literature review or an exhaustive review of the articles. Rather, we seek to identify new opportunities for rigorous and relevant research, research that has the potential of differentiating and enhancing POM within the Operations Management literature.     

Organizational Discourse: Domains,Debates, and Directions

Interest in the analysis of organizational discourse has expanded rapidly over the last two decades. In this article, we reflect critically on organizational discourse analysis as an approach to the study of organizations and management, highlighting both its strengths and areas of challenge. We begin with an explanation of the nature of organizational discourse analysis and outline some of the more significant contributions made to date. We then discuss existing classifications of approaches to the study of organizational discourse and suggest that they fall into two main categories: classifications by level of analysis and classifications by type of method. We argue that both of these approaches are inherently problematic and present an alternative way to understand the varieties of approaches to the analysis of organizational discourse based on within domain and across domain characterizations. We conclude with a discussion of the challenges that remain in the development of organizational discourse as an area of study and point to some of the opportunities for important and unique contributions to our understanding of organizations and management that this family of methods brings.     

Corporate Governance and Democracy: The Stakeholder Debate Revisited

'Stakeholding' is a term laden with manymeanings. In this paper we attempt to put someorder on the discourse by confining attentionto the corporation. We assess the originsand the intellectual foundations of the 'shareholder versus stakeholder' debate. We askwhether and how 'stakeholding' might be a morelogical or rational system, a fairer or moredemocratic system, and one that provides betterperformative outcomes. Each of these claims isassessed in respect to the micro firmperspective and the macro economy-wideperspective.One of the most difficult and neglected areasin the stakeholding debate concerns thepracticalities of its implementation. The papertackles this issue directly, at both thedomestic and the international level. We asknot only how stakeholding might be sensiblyintroduces within a national context but alsowhat it means to discuss stakeholding inrespect to transnational enterprises.     

Robust Priors in Nonlinear Panel Data Models

Many approaches to estimation of panel models are based on an average or integrated likelihood that assigns weights to different values of the individual effects. Fixed effects, random effects, and Bayesian approaches all fall into this category. We provide a characterization of the class of weights (or priors) that produce estimators that are first‐order unbiased. We show that such bias‐reducing weights will depend on the data in general unless an orthogonal reparameterization or an essentially equivalent condition is available. Two intuitively appealing weighting schemes are discussed. We argue that asymptotically valid confidence intervals can be read from the posterior distribution of the common parameters when N and T grow at the same rate. Next, we show that random effects estimators are not bias reducing in general and we discuss important exceptions. Moreover, the bias depends on the Kullback–Leibler distance between the population distribution of the effects and its best approximation in the random effects family. Finally, we show that, in general, standard random effects estimation of marginal effects is inconsistent for large T, whereas the posterior mean of the marginal effect is large‐T consistent, and we provide conditions for bias reduction. Some examples and Monte Carlo experiments illustrate the results.     

Genericity and Markovian Behavior in Stochastic Games

This paper examines Markov perfect equilibria of general, finite state stochastic games. Our main result is that the number of such equilibria is finite for a set of stochastic game payoffs with full Lebesgue measure. We further discuss extensions to lower dimensional stochastic games like the alternating move game.     

Guanxi and professional leadership in contemporary Sino-American joint ventures in mainland China

In Sino-American joint ventures in mainland China, cross-cultural differences regarding the relational components can produce misunderstanding and conflict. The Chinese relational system called Guanxi can render Western leadership relations such as articulated in Leader-member Exchange Theory (LMX), compromised. We examine the roles of a post modern organization career-based leadership relationship (LMX) and the Confucianism supported feudal/family-based relationship (guanxi) in building successful organizational cultures in contemporary mainland China. We discuss the weakening of traditional guanxi by the events of the last fifty years. Recommendations for synthesizing the two different relational components into a third culture are offered and discussed.     

Robotic-Cell Scheduling: Special Polynomially Solvable Cases of the Traveling Salesman Problem on Permuted Monge Matrices

In this paper, we introduce the 1 − K robotic-cell scheduling problem, whose solution can be reduced to solving a TSP on specially structured permuted Monge matrices, we call b-decomposable matrices. We also review a number of other scheduling problems which all reduce to solving TSP-s on permuted Monge matrices. We present the important insight that the TSP on b-decomposable matrices can be solved in polynomial time by a special adaptation of the well-known subtour-patching technique. We discuss efficient implementations of this algorithm on newly defined subclasses of permuted Monge matrices.