Application of interactive possibilistic linear programming to aggregate production planning with multiple imprecise objectives

Aggregate production planning (APP) addresses matching supply to forecast demand, with varying customer orders over the intermediate planning horizon. In real-world APP problems, input data and related parameters are commonly imprecise because information is incomplete or unavailable, and the decision maker (DM) must simultaneously consider conflicting objectives. This study develops an interactive possibilistic linear programming (i-PLP) approach to solve multi-product and multi-time period APP problems with multiple imprecise objectives and cost coefficients by triangular possibility distributions in uncertain environments. The imprecise multi-objective APP model designed here seeks to minimise total production costs and changes in work-force level with reference to imprecise demand, cost coefficients, available resources and capacity. Additionally, the proposed i-PLP approach provides a systematic framework that helps the decision-making process to solve fuzzy multi-objective APP problems, enabling a DM to interactively modify the imprecise data and parameters until a set of satisfactory solutions is derived. An industrial case demonstrates the feasibility of applying the proposed approach to a practical multi-objective APP problem.     

RETHINKING MACROECONOMICS: WHAT FAILED,AND HOW TO REPAIR IT

The standard macroeconomic models have failed, by all the most important tests of scientific theory. They did not predict that the financial crisis would happen; and when it did, they understated its effects. Monetary authorities allowed bubbles to grow and focused on keeping inflation low, partly because the standard models suggested that low inflation was necessary and almost sufficient for efficiency and growth. After the crisis broke, policymakers relying on the models floundered. Notwithstanding the diversity of macroeconomics, the sum of these failures points to the need for a fundamental re‐examination of the models—and a reassertion of the lessons of modern general equilibrium theory that were seemingly forgotten in the years leading up to the crisis. This paper first describes the failures of the standard models in broad terms, and then develops the economics of deep downturns, and shows that such downturns are endogenous. Further, the paper argues that there have been systemic changes to the structure of the economy that made the economy more vulnerable to crisis, contrary to what the standard models argued. Finally, the paper contrasts the policy implications of our framework with those of the standard models.     

The impact of training on the formulation of ill-structured problems

Problem structuring heuristics and creative thinking techniques have been advanced as useful approaches for solving ill-structured problems. Unfortunately, little controlled experimentation has been done to test the effectiveness of these techniques. This paper describes an experiment in which the effects of training in the use of a problem-structuring heuristic and creative thinking on the quality and quantity of problem statements are investigated. The experiment illustrates that such training does have a positive impact on problem formulation quality and quantity.     

A simple linear time approximation algorithm for multi-processor job scheduling on four processors

Multiprocessor job scheduling problem has become increasingly interesting, for both theoretical study and practical applications. Theoretical study of the problem has made significant progress recently, which, however, seems not to imply practical algorithms for the problem, yet. Practical algorithms have been developed only for systems with three processors and the techniques seem difficult to extend to systems with more than three processors. This paper offers new observations and introduces new techniques for the multiprocessor job scheduling problem on systems with four processors. A very simple and practical linear time approximation algorithm of ratio bounded by 1.5 is developed for the multi-processor job scheduling problem P ₄|fix|C _max, which significantly improves previous results. Our techniques are also useful for multiprocessor job scheduling problems on systems with more than four processors.     

基于和谐管理理论的武器装备采购质量管理研究

武器装备采购质量管理是武器装备采购方对装备需求论证、生产竞标、装备制造、监督、激励和评价等过程加以控制来提高装备质量的行为,这一行为的基本特征是复杂性。针对目前我国武器装备采购质量管理中的问题,根据和谐管理理论应对复杂性的机理,提出了武器装备采购质量管理的和谐耦合体系,并探讨了这一体系在军用飞机采购中的应用。其核心思想是同时建立设计优化机理指导下的控制机制和能动致变机理下的诱导机制,对于那些可通过优化设计的质量问题运用规定性的控制机制来解决,由人的不确定性引起的、不可用规定的硬性措施解决的质量问题用能动致变的演化机制来应对,最后还要注意两种机制之间的互动、转化和调节。     

ON PREDICTING COMPUTATIONAL TIME OF A BRANCH AND BOUND ALGORITHM FOR THE ASSIGNMENT OF FACILITIES

Experience with branch and bound algorithms indicates that computational time is a function of not only the size of the problem, but also the nature of the input data. This paper formulates statistically-based variables which describe certain characteristics of the input data and experimentally evaluates their ability to predict computational time for one branch and bound algorithm, the relative location of facilities or “plant layout” problem. Results suggest that the described experimental procedure may be useful for an a priori assessment of the computational difficulty of specific branch and bound problems.     

Designing communication support systems for strategic planning

While as a distinct and intermittent managerial activity planning is slowly dying, in a systematic and continuous context it is rapidly growing! More and more organizations are beginning to realize that planning entails ongoing learning and adaptation of people rather than one-shot, pseudo-scientific analysis of abstract problems. To facilitate this fundamental transformation in organizational thinking, new electronic management support systems are being created. These systems will facilitate collaborative problem exploration through improved managerial communication. In effect, they will actively assist managers to understand and manage the relationships between the strategic planning process and the other corporate processes such as budgeting, capital investment, performance evaluation and employee compensation.     

Developing an understanding of lean thinking in process industries

The research described in this article has set out to determine the extent to which lean thinking is being adopted as a manufacturing philosophy by process industries. It concerns the application and examination of key lean manufacturing principles, namely, the alignment of production with demand, the elimination of waste, the integration of suppliers (IS) and the creative involvement of the workforce in improvement activities, to a range of process industry types based on Dennis and Meredith's taxonomy of process industry transformation systems [Dennis, D. and Meredith, J., 2000a. An empirical analysis of process industry transformation systems. Management Science, 46 (8), 1085–1099]. Seventy-nine process industry product streams across 62 sites were studied. In addition, a five-site investigative field study was also undertaken. The findings demonstrate that lean practices associated with the elimination of waste are consistently used for improving manufacturing performance throughout the taxonomy of process industries but practices associated with other lean principles are inconsistently applied. In addition, explanations are provided on the appropriateness of lean thinking as a manufacturing philosophy and a strategy for improving manufacturing performance in different process industry types, and on the extent to which lean principles and practices are dependent on the characteristics of process industry transformation systems.     

Finding disjoint paths with related path costs

We consider routing in survivable networks that provide protection against node or link failures. In these networks resilience against failures is provided by routing connections on pairs of disjoint paths called primary and backup paths. The primary path of a connection carries its traffic under normal circumstances and in the eventuality of a network failure effecting the primary path the connection traffic (all or some portion of it) is rerouted over its backup path. In an online setting as connection requests arrive a pair of disjoint primary and backup paths of least total cost (under some link cost metric) are selected to route the connections. In many situations the cost metric used for the primary path differs from the cost metric used for the backup path. Also in many realistic settings these two cost metrics are related to each other. In this paper we study the problem of finding a pair of edge or node disjoint paths of least total cost where the cost of the primary path is the total cost of its links while the cost for the backup path is α times the sum of the cost of its links, for some given α < 1. We show that the problem is hard to approximate to within a factor for any positive . In addition we show that the problem is complete for a set of hard to approximate problems. On the positive side we show that a simple algorithm achieves an approximation ratio of for the problem.     

Some inverse min-max network problems under weighted l1 and l∞ norms with bound constraints on changes

We consider some inverse min-max (or max-min) network problems. Such an inverse problem is to modify the weights with bound constraints so that a given feasible solution becomes an optimal solution of a min-max (or max-min) network problem, and the deviation of the weights, measured by the weighted l ₁ norm or weighted l _∞ norm, is minimum. In this paper, we present strongly polynomial time algorithms to solve the inverse min-max spanning tree problem and the inverse maximum capacity path problem.     

Modular design of integrated databases in production management systems

Abstract

Complexity is a serious problem with respect to the application of information technology in the field of production management. This paper presents an overview of the more fundamental problems encountered and proposes a solution for some of those problems in the form of modular decomposition of the conceptual database structure. It is argued that the complexity of information systems is closely connected to the complexity of the organization. Therefore a condition for the realization of integrated information systems for production management is a simplification of the organizational structure by way of defunctionalization and the forming of autonomous units.     

Strategies for leader cognition: Viewing the glass “half full” and “half empty”

Leader cognition proves to be central to organizational functioning as leaders generate solutions and provide direction when organizations encounter problems. This study examined the effects of utilizing different general thinking strategies for thinking through organizational problems on the formation of problem solutions and statements articulating a future vision. Specifically, the effects of focusing on the positive, the negative, or balancing positivity and negativity were examined regarding their influence on the quality, originality, and elegance of solutions and the viability of vision statements. Participants were asked to assume the role of a leader in an educational technology firm and provide a solution and vision statement to address the firm's challenges. The results revealed that a positivity strategy – thinking about positive outcomes and means for attaining success – resulted in lower quality solutions and less viable visions than a balanced positive–negative strategy—either thinking about negative outcomes and means for attaining success or positive outcomes and means for avoiding failure. Solution originality, however, was moderated by attribution of responsibility such that thinking about negative outcomes and avoiding failure resulted in more original solutions when responsibility for the conditions confronting the firm could be attributed externally rather than internally. The implications of these findings for understanding leader cognition and performance are discussed.     

Measuring the leanness of manufacturing systems—A case study of Ford Motor Company and General Motors

In spite of the vast research published on lean manufacturing systems in several disciplines in the last decade, the concept remains underdeveloped for two reasons. First, it lacks a generally accepted definition. Different authors define lean in terms of its objectives, which vary, overlap and differ in different firms. Second, no study has developed a systematic and relative measure of lean production systems. With the lack of such a measure, two companies cannot be rated objectively on their progress toward becoming lean. This paper has two goals: first, to define manufacturing leanness as a unifying concept, and, second, to develop a systematic, long-term measure of leanness. Manufacturing leanness is a strategy to incur less input to better achieve the organization’s goals through producing better output. The systematic measure of leanness has seven characteristics: relative, dynamic, long-term fuzzy logical, objective, integrative and comprehensive. The leanness measure utilizes the fuzzy-logic methodology since lean is a matter of degree. Applying the measure to compare the production leanness of Ford Motor Company and General Motors, the paper selects Honda Motor Company as the benchmarking firm. Selecting just-in-time (JIT), Kaizen, and quality controls as lean attributes, the paper uses surrogates for these attributes extracted from audited financial statements over the years 2001–2003. The results show that Ford’s system is more than 17% leaner than GM’s system vis-à-vis the benchmarked company’s system.     

Honeynet games: a game theoretic approach to defending network monitors

A honeynet is a portion of routed but otherwise unused address space that is instrumented for network traffic monitoring. It is an invaluable tool for understanding unwanted Internet traffic and malicious attacks. We formalize the problem of defending honeynets from systematic mapping (a serious threat to their viability) as a simple two-person game. The objective of the Attacker is to identify a honeynet with a minimum number of probes. The objective of the Defender is to maintain a honeynet for as long as possible before moving it to a new location within a larger address space. Using this game theoretic framework, we describe and prove optimal or near-optimal strategies for both the Attacker and the Defender. This is the first mathematically rigorous study of this increasingly important problem on honeynet defense. Our theoretical ideas provide the first formalism of the honeynet monitoring problem, illustrate the viability of network address shuffling, and inform the design of next generation honeynet defense systems.     

NATURE OF PROBLEM ILL-STRUCTUREDNESS: IMPLICATIONS FOR PROBLEM FORMULATION AND SOLUTION

The distinction between ill-structured and well-structured decision problems is extended in this paper to include the degree of familiarity that a decision maker has with the initial state of the problem, its desired state, and appropriate transformations for resolving the problem. It is shown that problem ill-structuredness may result from inadequate information regarding any of these components and that the nature of problem ill-structuredness has important implications for problem formulation and solution. A decision tree is presented which represents strategies for either reformulating primary problems of each class of ill-structuredness to a more readily solved form, or solving the problem as initially formulated.     

On the number of local minima for the multidimensional assignment problem

The Multidimensional Assignment Problem (MAP) is an NP-hard combinatorial optimization problem occurring in many applications, such as data association, target tracking, and resource planning. As many solution approaches to this problem rely, at least partly, on local neighborhood search algorithms, the number of local minima affects solution difficulty for these algorithms. This paper investigates the expected number of local minima in randomly generated instances of the MAP. Lower and upper bounds are developed for the expected number of local minima, E[M], in an MAP with iid standard normal coefficients. In a special case of the MAP, a closed-form expression for E[M] is obtained when costs are iid continuous random variables. These results imply that the expected number of local minima is exponential in the number of dimensions of the MAP. Our numerical experiments indicate that larger numbers of local minima have a statistically significant negative effect on the quality of solutions produced by several heuristic algorithms that involve local neighborhood search.Partially supported by the NSF grant DMI-0457473.     

具有隐藏故障的多状态竞争失效系统检测策略研究

复杂工业系统的故障中有40%属于隐藏故障,若隐藏故障得不到及时消除,则可能导致巨大的经济损失。本文针对具有隐藏故障的多状态竞争失效系统,在考虑不完全检测的基础上,对其进行了维修建模。首先,基于制定的视情维修策略,分析了系统的更新情形;然后,基于所推导出的各种系统更新情形的发生概率,建立了以期望成本率为目标函数,以检测间隔时间为决策变量的维修模型。最后,以电容器组为例对所构建维修模型的适用性和有效性进行了验证,研究结果表明,检测质量对检测策略的制定有重要影响,因此研究具有隐藏故障的多状态竞争失效系统的检测策略时,有必要考虑检测误差。本文提出的维修建模方法不仅能在一定程度上丰富多状态竞争失效系统的维修策略理论与方法,还能为工程实际中复杂工业系统的维修工作提供理论基础与决策依据。     

Rumination for innovation? Analysing the longitudinal effects of work-related rumination on creativity at work and off-job recovery

Work-related rumination is not a single construct, but consists of a dimension associated with negative emotions or affect (affective rumination), and a dimension associated with reflective thinking and applying strategies to solve problems (problem-solving pondering). In this three-wave longitudinal study across two years (N?=?630) we investigated whether the relationships between work-related rumination, off-job recovery, and creativity at work varied along the two dimensions of work-related rumination. In addition, we tested whether the relationships followed normal, reversed, or reciprocal causation. The results showed, first, that in a one-year perspective affective rumination, but not problem-solving pondering, was negatively related to off-job recovery and that problem-solving pondering, but not affective rumination, was positively related to creativity at work. Second, in a two-year perspective, reversed effects were detected as creativity at work was negatively related to affective rumination and positively to off-job recovery. Our results suggest that the quality of work-related thoughts determines whether the outcome is beneficial or detrimental. Occupational health interventions that only advise employees to stop thinking about work during off-job time, may therefore be too simplistic.     

Solving the Economic Lot-Scheduling Problem Using the Method of Prime Subperiods

In recent years the reported successes of Japanese production systems, particularly the just-in-time approach to inventory control, has caused managers to focus more of their attention on efficient decision-making procedures for determining production schedules that minimize inventory costs. One such potential area of attention is the economic lot-scheduling problem (ELSP), which occurs in a variety of manufacturing environments where machining operations are prevalent. The economic lot-scheduling problem addresses the determination of lot sizes for N products with constant demand (and cycled through one machine with a given production rate) to minimize setup and inventory costs. The most successful solution approaches to the ELSP have been based on the concept of a basic period that is of sufficient length for the production of all items, even though each item might not be produced during each repetition of the basic period. This paper proposes a heuristic approach to the solution of the ELSP (referred to as the method of prime subperiods), which is an extension of the basic period approaches. The procedure is described and demonstrated via an example and then tested using a set of six example problems previously employed in the literature related to the ELSP. The results indicate as good or superior performance by the proposed method of prime subperiods.     

Attacking the Market Split Problem with Lattice Point Enumeration

The market split problem was proposed by Cornuéjols and Dawande as benchmark problem for algorithms solving linear systems with 0/1 variables. Here, we present an algorithm for the more general problem A · x = b with arbitrary lower and upper bound on the variables. The algorithm consists of exhaustive enumeration of all points of a suitable lattice which are contained in a given polyhedron. We present results for the feasibility version as well as for the integer programming version of the market split problem which indicate that the algorithm outperforms the previously published approaches to this problems considerably.