bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Number of Component Failures in Systems Whose Component Lives are Exchangeable
Authors: Ross Sheldon M. , Shahshahani Mehrdad , Weiss Gideon 
Published: October 2008

We consider a system that is composed of finitely many independent components each of which is either “on” or “off” at any time. The components are initially on and they have common on-time distributions. Once a component goes off, it remains off forever. The system is monotone in the sense that if the system is off whenever each component in a subset S (called a cut set) of components is off, then that is also true for every subset of components containing S. We are interested in studying the properties of N, the number of components that are off at the moment the system goes off. We compute the factorial moments of N in terms of the reliability function. We also prove that N is an increasing failure rate average random variable and present a duality result. We consider the special structure in which the minimal cut sets do not overlap and we prove a conjecture of El-Neweihi, Proschan and Sethuraman which states that N is an increasing failure rate random variable. Then we consider the special case of nonoverlapping minimal path sets, and in the final section we present an application to a shock model.
Optimal Stopping for a Markov Process: A New Characterisation of the Optimal Policy
Authors: McNamara J. M. 
Published: October 2008

This paper is concerned with optimal stopping for a continuous time (nonstationary) Markov process. The stopping problem is formulated in terms of a continuation cost with zero stopping cost. A new characterisation of the optimal continuation region is given. This characterisation is then used to obtain further results about optimal stopping.
An Exact Penalty Method for Mixed-Integer Programs
Authors: Blair C. E. , Jeroslow R. G. 
Published: October 2008

It is shown that a norm penalty method is exact for mixed integer programs in rational data, in the sense that the minimization of the criterion plus penalty over the nonnegativities and integrality constraints has the same set of globally optimal solutions as does the mixed integer program with the equality constraints present. This result is then extended to mixed-integer programs with complementarity constraints. An example shows that no differentiable penalty can be exact for mixed integer programs.
Exponential Lower Bounds on a Class of Knapsack Algorithms
Authors: Hausmann Dirk , Kannan Ravindran , Korte Bernhard 
Published: October 2008

The 0-1 knapsack problem is a well known NP-hard optimization problem. The proof of the generally believed hypothesis that there is no polynomial optimization algorithm for this problem would settle the famous NP ≠ P question. We show here the nonexistence of a polynomial knapsack algorithm within the class of algorithms having restricted access to the input. Algorithms for the problem max{c(S): a(S) ≤ b, S ⊆ En} that can only check the sign of a(S) − b cannot have a better performance guarantee than the greedy algorithm; furthermore even if they can exploit the order of the densities ci/ai, 1 ≤ i ≤ n, or of the weights a(S), S ⊆ En, they cannot be guaranteed to find the optimum.
The Contraction Mapping Approach to the Perron-Frobenius Theory: Why Hilbert's Metric?
Authors: Kohlberg Elon , Pratt John W. 
Published: October 2008

The Perron-Frobenius Theorem says that if A is a nonnegative square matrix some power of which is positive, then there exists an x0 such that Anx/‖Anx‖ converges to xn for all x > 0. There are many classical proofs of this theorem, all depending on a connection between positively of a matrix and properties of its eigenvalues. A more modern proof, due to Garrett Birkhoff, is based on the observation that every linear transformation with a positive matrix may be viewed as a contraction mapping on the nonnegative orthant. This observation turns the Perron-Frobenius theorem into a special ease of the Banach contraction mapping theorem. Furthermore, it applies equally to linear transformations which are positive in a much more general sense. The metric which Birkhoff used to show that positive linear transformations correspond to contraction mappings is known as Hilbert's projective metric. The definition of this metric is rather complicated. It is therefore natural to try to define another, less complicated metric, which would also turn positive matrices into contractions. The main result of this paper is that, essentially, this is impossible. The paper also gives some other results of possible interest in themselves, as well as enough background to make the presentation self-contained.
Duality and Pricing in Multiple Right-Hand Choice Linear Programming Problems
Authors: Granot Daniel , Granot Frieda , Johnson Ellis L. 
Published: October 2008

The main problem studied in this paper is a linear programming problem with multiple right-hand choice of the form Min{cx ∣ x ≥ 0, Ax ≥ b for some b ∈ B}, where B is a finite subset of Rm. The dual to the above problem is introduced to be of the form Max{Minb∈B π(b) ∣ π(A) ≤ c, π ∈ p}, where P is the collection of all subadditive, positively homogeneous and monotone functions from Rm to the extended real line. We prove that the above pair of problems satisfy both weak and strong duality, and provide necessary and sufficient conditions for strong duality to hold when the dual functions π are restricted to be linear. It is shown that the class of functions P arises naturally even in linear programming, i.e., when |B| = 1. Indeed, linear functions will not suffice for pricing functions in a degenerate linear programming problem. In fact, in this case the pricing function p is piecewise linear, superadditive and positively homogeneous and thus concave, i.e., −p ∈ P. On the other hand, we show that the pricing function of the multiple right-hand choice linear program is not necessarily concave. This indicates the difficulties of pricing in integer programming. Finally, a more symmetric pair of dual problems is introduced, and duality relationship between the two problems is studied.
Renewal Decisions when Category Life Distributions are of Phase-Type
Authors: Assaf David 
Published: October 2008

A system must operate for t units of time. A certain component is essential for the operation of the system and must be replaced by a new component whenever it fails. There are n types of replacement categories available (with an infinite supply of each) differing only in price and life distribution. The main problem is to select the proper category for replacement at any time a failure occurs, so as to minimize the total expected cost of running the system. In this paper the problem is studied when category life distributions have a common matrix phase type representation. The generalized Erlang and the hyperexponential distributions, as well as coherent structures of the latter distributions, are some special cases of this representation. Our main result is that in many of these cases, the problem of finding an optimal replacement policy is reduced to that of determining a specified number (at most n − 1) of points on the real time axis. Also provided is a condition for identifying categories which should never be used, thus reducing the problem by eliminating them. This work generalizes previous results obtained when all category life distributions were assumed exponential. Several illustrative examples are provided.
The Fair Division of a Fixed Supply Among a Growing Population
Authors: Thomson William 
Published: October 2008

We reconsider the traditional problem of fair division. Division principles should be general enough to accommodate changes in what is to be divided as well as variations in the number of agents among whom the division is to take place. In the usual treatment of the question, this number is assumed to be fixed. Here, we explicitly allow it to vary. Agents are assumed to have von Neumann–Morgenstern utility functions and division problems are defined as subsets of the utility space. Our approach is axiomatic. Apart from the familiar axioms of Pareto-optimality, scale invariance, continuity and anonymity, we formulate and impose an axiom of monotonicity with respect to changes in the number of agents, stating that if sacrifices have to be made to support an additional agent, then everybody should contribute. There is a unique division principle that satisfies them all: it is the natural extension to the n-person case of the two-person solution proposed by Kalai and Smorodinsky.
Minimum Convex Cost Dynamic Network Flows
Authors: Orlin James B. 
Published: October 2008

This paper presents and solves in polynomial time the minimum convex cost dynamic network flow problem, an infinite horizon integer programming problem which involves network flows evolving over time. The model is a finite network in which each arc has an associated transit time for flow to pass through it. An integral amount of flow is to be sent through arcs of the network in each period over an infinite horizon so as to satisfy conservation of flow from some fixed period on. Furthermore, the net amount of flow “in transit” is assumed fixed over the infinite horizon. The objective is to minimize the average convex cost per period of sending flow. This problem is a generalization of the minimum convex cost network flow problem, the maximum throughput dynamic network flow problem, and the minimum cost-to-time ratio circuit problem. Furthermore, the model has applications in periodic production and transshipment, airplane scheduling, cyclic capacity scheduling, and cyclic staffing. To solve the dynamic network flow problem, one first obtains an optimal continuous-valued flow which repeats every period. The fractional variables of this solution may be rounded in such a way as to obtain an optimal integral flow which repeats every q periods, where q is the least common denominator of the fractional parts of the continuous flow. Furthermore, this integral flow is also an optimal continuous flow.
Dichotomous Search for Random Objects on an Interval
Authors: Hassin R. , Henig M. 
Published: October 2008

A set of objects to be searched is represented by a set of points lying in an interval of integers. We wish to identify these points within unit-intervals through a dichotomous search, minimizing the expected cost of the search. The optimal search strategy may depend on the information gained at each stage of the search. It is shown here that for some cases there exists a common optimal strategy. This strategy is generally different from the bisection procedure, and is independent of the number of objects in the interval. As a matter of fact, at each stage of the search a partition of the interval is given and the only information needed for searching a subinterval of this partition is that it still contains an unidentified point.
Convergence Rates for the Optimal Values of Allocation Processes
Authors: Artstein Zvi 
Published: October 2008

The optimal allocation process is of the following type. A sequence of functions (production functions) f1, f2, …, is given, each mapping R+n into [0, ∞). Along with it a vector q > 0 in R+n (vector of resources) is provided. For each integer k we consider the problem [Formula: see text] Here R+n is the nonnegative orthant of the n-dimensional Euclidean space. Inequalities between vectors are taken coordinatewise. In this paper we consider the case where the functions fi are subject to randomness. Specifically, they are generated as independent random drawings from a common distribution. In particular fi = fi(x, ω) with ω being in a probability space, and the solutions xi might depend on u, as well as on k and q. The detailed technical conditions are displayed in §2. We are interested in limit properties, as k → ∞, of the optimal values of the allocation process.
Storage Processes with Markov Additive Input and Output
Authors: Kaspi Haya 
Published: October 2008

We consider a storage process to which both input and output are Markov additive processes defined on the same driving Markov process X. We study the process (X, W) where W is the content of the system. This paper has two main parts. The first uses excursion theory of Markov processes to study ladder processes of Markov additive processes (not necessarily arising from storage processes). This analysis enables us to find conditions for the existence of a limiting distribution for the Markov process (X, W). The second part uses a representation of the invariant measure for (X, W) to study the problem of level crossings of the content process W.
Structural Evolution Through Idiosyncratic Jobs: The Potential for Unplanned Learning
Authors: Miner Anne S. 
Published: October 2008

This paper describes an evolutionary model of organizational change through the selective retention of jobs. This type of change can operate in addition to top-down planned organizational change, providing “another engine” of organizational transformation over time. All evolutionary change processes require that there be a system for replicating activities over time, a source of variation in activities, and mechanisms which permit some activities to persist while others do not. In this model, formalized job systems and related management practices provide the mechanism for the replication of job activities. Idiosyncratic jobs—or jobs created around particular people rather than in the abstract—serve as a mechanism for unplanned variation in sets of job duties. Finally managerial actions such as layoffs, reorganizations, budget changes and copying jobs from other areas lead to the selective retention of some sets of job activities over others. The organizational change created by these processes may or may not be adaptive for the organization. The outcome will depend on such factors as the birth, death and imitation rates for idiosyncratic and other jobs, as well as the criteria used for job birth and job termination. Adaptation is possible, but is a function of complex, nonlinear constraints. Specific organizational processes that determine these factors are discussed. The model implies that adaptive change can occur in the absence of clear and consistent goals. Thus, the model's implications contradict the frequent assumption of strategic planning literatures that clear and stable goals are necessary for adaptive organizational change. Formalization is necessary for the organization to maintain over time those job activities which have proved to be useful innovations. Thus, the model's implications also contradict the assumption in structural contingency theory that formalization deters adaptive change. Although consistent with other theories of evolutionary organizational change, the model extends prior work by detailing concrete mechanisms, clarifying boundary conditions for the process, and stressing that adaptation is feasible but definitely not assured. The outcome depends in part upon managerial attention to organizational processes rather than to outcomes, and “benign opportunism”—or creative attention to unfolding organizational competencies. Finally, the paper outlines the potential of the model for further study, especially for empirical research on evolutionary change processes and on organizational learning. The evolutionary change process described can be seen as a form of trial-and-error learning in which retained jobs constitute the organization's memory. It is distinct from many other organizational learning models, however, because the source of innovation—idiosyncratic jobs—is not planned in advance by top management, and may be unrelated to current aspirations of the dominant coalition.
Integrating Strategic, Organizational, and Human Resource Perspectives on Mergers and Acquisitions: A Case Survey of Synergy Realization
Authors: Larsson Rikard , Finkelstein Sydney 
Published: October 2008

Mergers and acquisitions are complex events in organizational life for which we have incomplete understanding, in part because researchers have tended to consider only partial explanations of them. The authors addressed that problem by developing a conceptual framework that integrates theoretical perspectives from economics, finance, and especially strategy, organization theory, and human resource management to offer a broader process-oriented integrative model. The integrative model explicitly describes how synergy realization is a function of the similarity and complementarity of the two merging businesses (combination potential), the extent of interaction and coordination during the organizational integration process, and the lack of employee resistance to the combined entity. The approach differs from traditional methods of studying mergers and acquisitions in three ways: (1) the success of a merger or acquisition is gauged by the degree of synergy realization rather than more removed and potentially ambiguous criteria such as accounting or market returns; (2) the key attribute of combination potential is conceptualized not only in terms of the similarities present across businesses, as in most studies of mergers and acquisitions, but also in terms of the production and marketing complementarities between the two businesses; and (3) the data are derived from a case survey method that combines the richness of in-depth case studies with the breadth and generalizability of large-sample empirical investigations. The framework was tested empirically across a sample of 61 mergers and acquisitions. The extent to which a merger or acquisition resulted in synergistic benefits was related to the strategic potential of the combination, the degree of organizational integration after the deal was completed, and the lack of employee resistance to the integration of the joining firms. Furthermore, the analysis revealed that (1) independent of any similarities across joining firms, the presence of complementary operations increased the probability of acquisition success by boosting synergy realization, (2) organizational integration was the single most important factor in explaining synergy realization, even to the extent that M&As with high combination potential were significantly more successful when coupled with high organizational integration than when integration efforts were less forceful, and (3) mergers and acquisitions that were dependent on gains from combining similar production and marketing operations tended to elicit more resistance from employees than M&As focused on realizing complementary benefits. Overall, the findings provide strong support for an integrative theory of mergers and acquisitions.
When Competitive Advantage Doesn't Lead to Performance: The Resource-Based View and Stakeholder Bargaining Power
Authors: Coff Russell W. 
Published: October 2008

What if rent from a competitive advantage is appropriated so it cannot be observed in performance measures? The resource-based view was not formulated to examine who will get the rent. Yet, this essay argues that the factors leading to a resource-based advantage also predict who will appropriate rent. Knowledge-based assets are promising because firm-specificity, social complexity, and causal ambiguity make them hard to imitate. However, the roles of internal stakeholders may grant them a great deal of bargaining power especially relative to investors. This essay integrates the resource-based view with the bargaining power literature by defining the firm as a nexus of contracts. This new lens can help to explain when rent will be generated and, simultaneously, who will appropriate it. In doing so, it provides a more robust theory of firm performance than the resource-based view alone. It is also suggested that this lens might be useful for examining other theories of firm performance.
How Buyers Cope with Uncertainty when Acquiring Firms in Knowledge-Intensive Industries: Caveat Emptor
Authors: Coff Russell W. 
Published: October 2008

Knowledge is frequently the focus of corporate acquisitions. It often cannot be acquired in efficient factor markets due to asymmetric information and because it may be bundled in teams or networks. However, variations in quality are harder to observe for knowledge-based assets than for tangible assets. This creates information dilemmas for buyers and, accordingly, a risk of overbidding, whenever a target is in a knowledge-intensive industry. This study found that most buyers took steps to mitigate the information dilemmas associated with knowledge-based assets. Specifically, buyers coped by (1) offering lower bid premia; (2) using contingent payment (e.g., stock or earnouts); and (3) increasing information both through lengthy negotiations and by avoiding tender offers. However, when the two firms drew on unrelated forms of expertise, buyers did not apply these strategies. It may be that a buyer's information needs are lower if little postacquisition integration is anticipated. An alternative explanation is that unrelated buyers may not be fully aware of the information dilemmas that they face. If so, they may be especially at risk of overbidding. The contingency relationship identified here with respect to related expertise warrants further study. Both the resource-based and diversification literatures presume that relatedness is universally important. This study suggests that it may be particularly relevant when there are knowledge-based assets.
The Impact of Information Technology on Coordination: Evidence from the B-2 “Stealth” Bomber
Authors: Argyres Nicholas S. 
Published: October 2008

This paper explores the economic processes through which information technology can facilitate coordination within and between firms. The paper presents and analyzes a case study of the B-2 “Stealth” bomber, an aircraft that was designed by four firms almost entirely by computer. The key information systems used in the project were (1) a common-access database to manage part designs and (2) an advanced system to perform structural analysis. These systems played a crucial role in enabling the four firms to coordinate their design and development activities precisely enough to meet the demanding engineering requirements imposed by the aircraft's unique mission. The paper analyses the case study using transaction cost, agency, and information processing theories. The analysis leads to several conclusions about the mechanisms through which the variables emphasized in these theories operated to improve coordination. First, the information systems aided coordination directly by making information processing less costly. Second, this enhanced information processing made the governance of the project more efficient. In particular, by establishing a “technical grammar” for communication, the systems helped to create social conventions around which firms could coordinate their activities, thus limiting the need for a hierarchical authority to promote coordination. This technical grammar also reduced governance costs by reducing asset-specificity, thereby reducing risks associated with contractual holdup. These interactions between communication and governance effects have not been elucidated in the IT/coordination literature. They are important in part because they help explain why the vertically disintegrated organization of the project proved viable. Finally, the systems facilitated decentralized decision-making by reducing agency (measurement) costs. This combination of effects may generalize to other settings in which information technology is used to promote coordination, especially in “virtual” or “disaggregated” corporations.