ppxscal/embedding_network huggingface dataset:
Gaining Benefits from Joint Forecasting and Replenishment Processes: The Case of Auto-Correlated Demand
Authors: Yossi Aviv
Venue: Manufacturing Service Operations Management (2001)

In this paper we consider a cooperative, two-level supply chain consisting of a retailer and a supplier. As in many practical settings, the supply chain members progressively observe market signals that enable them to explain future demand. The demand itself evolves according to an auto-regressive time series. We examine three types of supply chain configurations. In the first setting, the retailer and the supplier coordinate their policy parameters in an attempt to minimize systemwide costs, but they do not share their observations of market signals. In the second setting, resembling many original vendor-managed inventory (VMI) programs, the supplier takes the full responsibility of managing the supply chain's inventory, but the retailer's observations of market signals are not transferred to him. In our third setting, reminiscent of collaborative forecasting and replenishment partnerships, inventory is managed centrally, and all demand related information is shared. We propose a set of stylized models to study the three settings and use them to provide managerial insights into the value of information sharing, VMI, and collaborative forecasting.
Existence of Solutions to Differential Inclusions and to Time Optimal Control Problems in the Autonomous Case
Authors: Arrigo Cellina, António Ornelas
Venue: SIAM Journal on Control and Optimization (2003)

We prove existence of solutions to upper semicontinuous differential inclusions and to time optimal control problems under conditions that are strictly weaker than the usual assumption of convexity.
On the order of triangular norms: comments on "A triangular norm hierarchy" by E. Cretu
Authors: Erich Peter Klement, Radko Mesiar, Endre Pap
Venue: Fuzzy Sets and Systems (2002)

In Cretu (Fuzzy Sets and Systems 120 (2001) 371), the members of the families of Frank, Dubois-Prade, Yager, and Hamacher t-norms, respectively, are compared (in a pointwise way) with the minimum, the product, and the Lukasiewicz t-norm. All these results are well-known and trivial. Moreover, these families of t-norms cannot only be compared with the three basic t-norms above, but all these families are monotone with respect to their index, a fact which is also well known and straightforward to prove (with the exception of the family of Frank t-norms whose monotonicity has been first proven in Butnariu and Klement, Triangular Norm-Based Measures and Games with Fuzzy Coalitions, Kluwer, Dordrecht, 1993).
Non-cryptanalytic attacks
Authors: Henry B. Wolfe
Venue: Cryptologia (2002)

When investigating activities involving computer related cases or where it is thought that a computer may hold useful evidence, occasionally files are encountered that have been encrypted. Encryption is a valid and legal process that enables anyone to protect the privacy of their data and/or communications. Unless the suspect is cooperative and provides not only the key but also the specific encryption software, analysis of potential evidence may not be practical or possible. This paper discusses alternatives where the suspect is not cooperative and keys are not willingly provided. The outcome of the investigation may, as well, depend on what resources are available to the investigator.
Optimised directional distance filter
Authors: Rastislav Lukac
Venue: Machine Graphics Vision International Journal (2002)

In this paper, a new adaptive directional distance filter especially for the impulse noise suppression in color images is provided. The proposed method takes advantage from the optimal filtering situation when only the affected samples are estimated, whereas noisy image points are passed to a filter output without change. For that reason, the proposed method is based on switching between the identity filter (no smoothing) and the directional distance filter that provides a maximum amount of the smoothing. In order to achieve the most precise control of the proposed method, three center-weighted directional distance filters are utilised to determine a parameter compared with a threshold value. This simple comparison serves as a switching control. After the optimisation of the threshold, it will be shown that the proposed method achieves a significant improvement of the filter performance in comparison with standard vector filter classes for a wide range of impulse noise corruption.
Requirements Planning with Substitutions: Exploiting Bill-of-Materials Flexibility in Production Planning
Authors: Anantaram Balakrishnan, Joseph Geunes
Venue: Manufacturing Service Operations Management (2000)

Designing product lines with substitutable components and subassemblies permits companies to offer a broader variety of products while continuing to exploit economies of scale in production and inventory costs. Past research on models incorporating component substitutions focuses on the benefits from reduced safety-stock requirements. This paper addresses a dynamic requirements-planning problem for two-stage multi product manufacturing systems with bill-of-materials flexibility, i.e., with options to use substitute components or subassemblies produced by an upstream stage to meet demand in each period at the downstream stage. We model the problem as an integer program, and describe a dynamic-programming solution method to find the production and substitution quantities that satisfy given multi period downstream demands at minimum total setup, production, conversion, and holding cost. This methodology can serve as a module in requirements-planning systems to plan opportunistic component substitutions based on relative future demands and production costs. Computational results using real data from an aluminum-tube manufacturer show that substitution can save, on average, 8.7% of manufacturing cost. We also apply the model to random problems with a simple product structure to develop insights regarding substitution behavior and impacts.
Prediction with a generalized cost of error function
Authors: C. W. J. Granger
Venue: Essays in econometrics: Spectral analysis, seasonality, nonlinearity, methodology, and forecasting (2001)

Classical prediction theory limits itself to quadratic cost functions, and hence least-square predictors. However, the cost functions that arise in practice in economics and management situations are not likely to be quadratic in form, and frequently will be non-symmetric. It is the object of this paper to throw light on prediction in such situations and to suggest some practical implications. It is suggested that a useful, although sub-optimal, manner of taking into account generalized cost functions is to add a constant bias term to the predictor. Two theorems are proved showing that under fairly general conditions the bias term can be taken to be zero when one uses a symmetric cost function. If the cost function is a non-symmetric linear function, an expression for the bias can be simply obtained.
Camel sequences and quadratic residues
Authors: V. A. Gurvich, Li Sheng
Venue: Discrete Applied Mathematics (2002)

Given an even cyclic (+1,-1) sequence s=(s0,...,s2n-1) which consists of n plus ones and n minus ones, let us compute i+j (mod 2n) for all n2 (+1, -1)-pairs (si, sj) and insert the obtained n2 numbers into 2n "boxes" b0, b1,....,b2n-1, where box bk contains the multiplicity of k. The cyclic sequence B(s)=(b0, b1,..., b2n-1) is referred to as the box distribution of s. The average cardinality of a box is n2/2n=n/2. Some sequences have quite remarkable box-distributions, "almost average everywhere with two big humps". For example, n=5, s=(+1+1-1-1+ 1-1+1-1-1+1), B=(3333133330)=(341 340); n=7, s=(+1+1+1-1+1-1-1- 1+1+1-1+1-1-1), B= (33333363333337)=(366 367). In general, given an odd n, the box-distributions (⌊n/2⌋n-1(n- 1)⌊n/2⌋n-1n) and (⌈n/2⌉n-11⌈n/2⌉n-10) as well as the sequences which generate them, will be called the camel distributions and camel sequences, respectively, up-camel and down-camel. For example, the first sequence above is down-camel, and the second one is up-camel. Here we prove that there are infinitely many 'camels' of both types. More precisely, for every prime n= 4j-1 we construct an up-camel sequence and for every prime n= 4j+1 a down-camel one. In both cases these sequences are related to quadratic residues and non-residues modulo n. Camel sequences have applications in extremal graph theory.
The influence of mental models and goals on search patterns during web interaction
Authors: Debra J. Slone
Venue: Journal of the American Society for Information Science and Technology (2002)

This article reports on a study that uses a new analysis and display tool to examine the influences of understanding the system and goals on end-user Internet searching. Thirty-one public library users were observed searching the Web and/or a Web-based on-line catalog. The study identified four user categories, distinguished by the number of search approaches employed. These included linking, use of search engines, URL use, on-line catalog searching, and searching within a specific Web-site domain. Results conclude that experience and motivation, elements of situational goals and mental models, work in tandem to determine search approaches, Web sites visited, and sources used. People who sought information for job-related or educational purposes were highly motivated. Thus, they were persistent. Those who had a great deal of Internet experience used an array of tools; while those with immature mental models of the Internet relied more heavily on the Web on-line catalog or off-line sources. People seeking information for recreational or personal use were not highly motivated. Whether experienced or not, they relied on serendipity, linking, and other tasks that were not cognitively overbearing. When searching became too difficult, they abandoned the Internet as an information source.
Computation of several cyclotomic Swan subgroups
Authors: Timothy Kohl, Daniel R. Replogle
Venue: Mathematics of Computation (2002)

Let Cl(OK[G]) denote the locally free class group, that is the group of stable isomorphism classes of locally free OK[G]-modules, where OK is the ring of algebraic integers in the number field K and G is a finite group. We show how to compute the Swan subgroup, T(OK[G]), of Cl(OK[G]) when K = Q(ζp), ζp a primitive p-th root of unity, G = C2, where p is an odd (rational) prime so that hp+ = 1 and 2 is inert in K/Q. We show that, under these hypotheses, this calculation reduces to computing a quotient ring of a polynomial ˚ we do the computations obtaining for several primes p a nontrivial divisor of Cl(Z[ζp]C2). These calculations give an alternative proof that the fields Q(ζp) for p=11, 13, 19, 29, 37, 53, 59, and 61 are not Hilbert-Speiser.
Bridging Epistemologies: the Generative Dance Between Organizational Knowledge and Organizational Knowing
Authors: Scott D. N. Cook, John Seely Brown
Venue: Organization Science (1999)

Much current work on organizational knowledge, intellectual capital, knowledge-creating organizations, knowledge work, and the like rests on a single, traditional understanding of the nature of knowledge. We call this understanding the "episte-mology of possession," since it treats knowledge as something people possess. Yet, this epistemology cannot account for the knowing found in individual and group practice. Knowing as action calls for an "epistemology of practice." Moreover, the epistemology of possession tends to privilege explicit over tacit knowledge, and knowledge possessed by individuals over that possessed by groups. Current work on organizations is limited by this privileging and by the scant attention given to knowing in its own right. Organizations are better understood if explicit, tacit, individual and group knowledge are treated as four distinct and coequal forms of knowledge (each doing work the others cannot), and if knowledge and knowing are seen as mutually enabling (not competing). We hold that knowledge is a tool of knowing, that knowing is an aspect of our interaction with the social and physical world, and that the interplay of knowledge and knowing can generate new knowledge and new ways of knowing. We believe this generative dance between knowledge and knowing is a powerful source of organizational innovation. Harnessing this innovation calls for organizational and technological infrastructures that support the interplay of knowledge and knowing. Ultimately, these concepts make possible a more robust framing of such epistemologically-centered concerns as core competencies, the management of intellectual capital, etc. We explore these views through three brief case studies drawn from recent research.
Representation and geometric computation using the extended Gaussian image
Authors: Hamid Zouaki
Venue: Pattern Recognition Letters (2003)

In this paper, some interesting tools to handle convex objects are presented. The approach is based on the representation of convex objects by their extended Gaussian image (EGI). A new approach for 3D convex object metamorphosis is explored. Some measures of similarity based on the EGI representation are also examined.
Automatic generation of fuzzy rule-based models from data by genetic algorithms
Authors: P. P. Angelov, R. A. Buswell
Venue: Information Sciences&mdash;Informatics and Computer Science: An International Journal (2003)

A methodology for the encoding of the chromosome of a genetic algorithm (GA) is described in the paper. The encoding procedure is applied to the problem of automatically generating fuzzy rule-based models from data. Models generated by this approach have much of the flexibility of black-box methods, such as neural networks. In addition, they implicitly express information about the process being modelled through the linguistic terms associated with the rules. They can be applied to problems that are too complex to model in a first principles sense and can reduce the computational overhead when compared to established first principles based models. The encoding mechanism allows the rule base structure and parameters of the fuzzy model to be estimated simultaneously from data. The principle advantage is the preservation of the linguistic concept without the need to consider the entire rule base. The GA searches for the optimum solution given a comparatively small number of rules compared to all possible. This minimises the computational demand of the model generation and allows problems with realistic dimensions to be considered. A further feature is that the rules are extracted from the data without the need to establish any information about the model structure a priori. The implementation of the algorithm is described and the approach is applied to the modelling of components of heating ventilating and air-conditioning systems.
Trust in the pi-calculus
Authors: Mark Hepburn, David Wright
Venue: Proceedings of the 3rd ACM SIGPLAN international conference on Principles and practice of declarative programming (2001)

We introduce a new system of trust analysis for concurrent and distributed systems using the &pi;-calculus[13, 14, 15] as a modelling tool. A Type system using boolean annotations guarantees that no run-time errors due to un trusted data being used in a trusted context are possible. We improve on other similar systems[18] by introducing a safe environment in which trust-coercion can be performed based on the results of run-time checks. An algorithm for reducing the most general types for the type system is presented.
Methods for true power minimization
Authors: Robert W. Brodersen, Mark A. Horowitz, Dejan Markovic, Borivoje Nikolic, Vladimir Stojanovic
Venue: Proceedings of the 2002 IEEE/ACM international conference on Computer-aided design (2002)

This paper presents methods for efficient power minimization at circuit and micro-architectural levels. The potential energy savings are strongly related to the energy profile of a circuit. These savings are obtained by using gate sizing, supply voltage, and threshold voltage optimization, to minimize energy consumption subject to a delay constraint. The true power minimization is achieved when the energy reduction potentials of all tuning variables are balanced. We derive the sensitivity of energy to delay for each of the tuning variables connecting its energy saving potential to the physical properties of the circuit. This helps to develop understanding of optimization performance and identify the most efficient techniques for energy reduction. The optimizations are applied to some examples that span typical circuit topologies including inverter chains, SRAM decoders, and adders. At a delay of 20% larger than the minimum, energy savings of 40% to 70% are possible, indicating that achieving peak performance is expensive in terms of energy. Energy savings of about 50% can be achieved without delay penalty with the balancing of sizes, supplies, and thresholds.
Practice Abstracts
Authors: Donald L. Keefer, Subodha Kumar, Natarajan Ramanan, Chelliah Sriskandarajah
Venue: Interfaces (2002)

Practice Abstracts carries short reports of specific current or recent OR/MS projects. Often these reports are based on existing documents, such as internal reports or company newsletters. We hope that these abstracts will be accessible, interesting, and valuable to practitioners in other organizations. Contributions should be sent for evaluation to the editor of "Practice Abstracts," Donald L. Keefer, Department of Supply Chain Management, Arizona State University, Box 874706, Tempe, Arizona 85287-4706 [don.keefer@asu.edu].
Inferring Balking Behavior From Transactional Data
Authors: Haim Mendelson, Ravindran R. Pillai, Lee K. Jones
Venue: Operations Research (1999)

Balking is the act of not joining a queue because the prospective arriving customer judges the queue to be too long. We analyze queues in the presence of balking, using only the service start and stop data utilized in Larson's Queue Inference Engine (Q.I.E.). Using an extension of Larson's congestion probability calculation to include balking we present new maximum likelihood, nonparametric, and Bayesian methods for inferring the arrival rate and balking functions. The methodology is applicable to businesses that wish to estimate lost sales because of balking arising from queuing-type congestion. The techniques are applied to a small transactional data set for illustrative purposes.
Discrete-Space Volterra Series Representations with Truncation Bounds
Authors: Irwin W. Sandberg
Venue: Multidimensional Systems and Signal Processing (2003)

We give a Volterra-series representation theorem for discrete-space input-output maps that are analytic. The theorem provides a bound on the error in approximating the series with its first p + 1 terms. Examples are given to illustrate how the theorem can be used.
Book Reviews
Authors: Benjamin Lev, Pilar Arroyo E. Lopez, John K. Visich, Gary M. Johnson, David Ben-Arieh, Ramon Rodriguez, Margaret M. Wiecek
Venue: Interfaces (2002)

The range of books reviewed is wide, covering theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems (no software is reviewed). In addition, we include books in other fields that emphasize technical applications. Publishers who wish to have their books reviewed should send them to Professor Benjamin Lev. We list the books received; not all books received can be reviewed because space is limited. Those who would like to review books are urged to send me their names, addresses, and specific areas of expertise. We commission all reviews and do not accept unsolicited book reviews. Readers are encouraged to suggest books that might be reviewed or to ask publishers to send me copies of such books.
KLAVA: a Java package for distributed and mobile applications
Authors: Lorenzo Bettini, Rocco De Nicola, Rosario Pugliese
Venue: Software&mdash;Practice Experience (2002)

Highly distributed networks have now become a common infrastructure for wide-area distributed applications whose key design principle is network awareness, namely the ability to deal with dynamic changes of the network environment. Network-aware computing has called for new programming languages that exploit the mobility paradigm as a basic interaction mechanism. In this paper we present the architecture of KLAVA, an experimental Java package for distributed applications and code mobility. We describe how KLAVA permits code mobility by relying on Java and present a few distributed applications that exploit mobile code programmed in KLAVA.
Contraction kernels and combinatorial maps
Authors: Luc Brun, Walter Kropatsch
Venue: Pattern Recognition Letters (2003)

Graph pyramids are made of a stack of successively reduced graphs embedded in the plane. Such pyramids overcome the main limitations of their regular ancestors. The graphs used in the pyramid may be region adjacency graphs, dual graphs or combinatorial maps. Compared to usual graph data structures, combinatorial maps offer an explicit encoding of the orientation of edges around vertices. Each combinatorial map in the pyramid is generated from the one below by a set of edges to be contracted. This contraction process is controlled by kernels that can be combined in many ways. This paper shows that kernels producing a slow reduction rate can be combined to speed up reduction. Conversely, kernels decompose into smaller kernels that generate a more gradual reduction. We also propose one sequential and one parallel algorithm to compute the contracted combinatorial maps.
Being Efficiently Fickle: A Dynamic Theory of Organizational Choice
Authors: Jack A. Nickerson, Todd R. Zenger
Venue: Organization Science (2002)

A central proposition in organization theory is that discrete organizational forms are matched to environmental conditions, market strategies, or exchange conditions. This paper develops a contrary theoretical proposition. We argue that efficiency may dictate modulating between discrete governance modes (i.e., structural modulation) in response to a stable set of exchange conditions. If governance choices are discrete, as much of organization theory argues, then the consequent steady-state functionality delivered by these organizational forms is itself discrete. However, if the desired functionality lies in-between the steady-state functionality delivered by two discrete choices, then efficiency gains may be available by modulating between modes. We develop an analytical model of structural modulation and examine factors that influence when modulation is ef- ficiency enhancing, as well as the optimal rate of modulation. We conclude that under certain conditions structural modulation is efficiency enhancing. Further, contrary to theories that highlight the potentially destructive consequences of inertia on organizational survival, we identify important efficiencyyielding benefits of inertia.