ppxscal/embedding_network huggingface dataset:
The competence-based view on the management of virtual web organizations
Authors: Ulrich J. Franke
Venue: Managing virtual web organizations in the 21st century: issues and challenges (2002)

The organizational concept of virtual Web organizations encompasses three organizational elements, namely the relatively stable virtual Web platform from which dynamic virtual corporations derive. Virtual corporations are interorganizational adhocracies that are configured temporally of independent companies in order to serve a particular purpose, such as joint R&D, product development, and production. The third element of this organizational construct is the management organization that initiates and maintains the virtual Web platform as well as forms and facilitates the operation of dynamic virtual corporations. Since the organizational concept of virtual Web organizations is hardly researched this chapter aims to provide readers with a better understanding of the organizational concept of virtual Web organizations and in particular of how such an organizational construct is managed. Based on empirical research the author developed a competence-based management model of virtual Web management organizations. This competence-based view of virtual Web management organizations presents an overview of a set of common sub-competencies underlying the three virtual Web management' s main competencies of initiating and maintaining virtual Web platforms and forming dynamic virtual corporations. Furthermore, the developed competence-based management model describes the content of the individual sub-competencies and it explains the purpose, the interrelateness and the temporal dimensions of the virtual Web management's subcompetencies.
A comparison of Chinese document indexing strategies and retrieval models
Authors: Robert W. P. Luk, K. L. Kwok
Venue: ACM Transactions on Asian Language Information Processing (TALIP) (2002)

With the advent of the Internet and intranets, substantial interest is being shown in Asian language information retrieval; especially in Chinese, which is a good example of an Asian ideographic language (other examples include Japanese and Korean). Since, in this type of language, spaces do not delimit words, an important issue is which index terms should be extracted from documents. This issue also has wider implications for indexing other languages such as agglutinating languages (e.g., Finnish and Turkish), archaic ideographic languages like Egyptian hieroglyphs, and other types of information such as data stored in genomic databases. Although comparisons of indexing strategies for Chinese documents have been made, almost all of them are based on a single retrieval model. This article compares the performance of various combinations of indexing strategies (i.e., character, word, short-word, bigram, and Pircs indexing) and retrieval models (i.e., vector space, 2-Poisson, logistic regression, and Pircs models). We determine which model (and its parameters) achieves the (near) best retrieval effectiveness without relevance feedback, and compare it with the open evaluations (i.e., TREC and NTCIR) for both long and title queries. In addition, we describe a more extensive investigation of retrieval efficiency. In particular, the storage cost of word indexing is only slightly more than character indexing, and bigram indexing is about double the storage cost of other indexing strategies. The retrieval time typically varies linearly with the number of unique terms in the query, which is supported by correlation values above 90%. The Pircs retrieval system achieves robust and good retrieval performance, but it appears to be the slowest method, whereas vector space models were not very effective in retrieval, but were able to respond quickly. For robust, near-best retrieval effectiveness, without considering storage overhead, the 2-Poisson model using bigram indexing appears to be a good compromise between retrieval effectiveness and efficiency for both long and title queries.
Why Are Forecast Updates Often Disappointing?
Authors: Kyle Cattani, Warren Hausman
Venue: Manufacturing Service Operations Management (2000)

Demand forecasts do not become consistently more accurate as they are updated. We present examples demonstrating this counterintuitive phenomenon and some theoretical results to explain its occurrence. Specifically, we analyze the effect of demand randomness on forecast-update performance. A surprising result is that under various theoretical models involving demand randomness alone, updated forecasts will be less accurate between 30% and 50% of the time.
An Introductory Tutorial on Stochastic Linear Programming Models
Authors: Suvrajeet Sen, Julia L. Higle
Venue: Interfaces (1999)

Linear programming is a fundamental planning tool. It is often difficult to precisely estimate or forecast certain critical data elements of the linear program. In such cases, it is necessary to address the impact of uncertainty during the planning process. We discuss a variety of LP-based models that can be used for planning under uncertainty. In all cases, we begin with a deterministic LP model and show how it can be adapted to include the impact of uncertainty. We present models that range from simple recourse policies to more general two-stage and multistage SLP formulations. We also include a discussion of probabilistic constraints. We illustrate the various models using examples taken from the literature. The examples involve models developed for airline yield management, telecommunications, flood control, and production planning.
Digital public broadcasting in Flanders: walking the tightrope
Authors: Tomas Coppens
Venue: Telematics and Informatics (2003)

In this article we examine the public remit of the digital plans of one lesser-known public service broadcaster: the Flemish VRT. The VRT has ambitious plans to introduce digital television into every Flemish household, despite the many uncertainties and constraints the corporation is facing. Focused on short and mid-term goals, the VRT seems to be ignoring doubts about its remit, raised by Europe and private competitors. So far, the VRT's digital activities have been characterized by the use of shaky technology, a lack of prospects for future funding and a vague, unimpressive remit. The corporation is, therefore, walking on a perilously thin tightrope.
Braving the broadcast storm: infrastructural support for ad hoc routing
Authors: Raghupathy Sivakumar, Prasun Sinha, Vaduvur Bharghavan
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2003)

Several routing algorithms for mobile ad hoc networks have been proposed in the recent past [Broch et al., The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks, Internet Draft draft-ietf-manet-dsr-03.txt, October 1999; Perkins et al., Ad Hoc On Demand Distance Vector (AODV) Routing, Internet Draft draft-ietf-manet-aodv- 04.txt, October 1999; Haas and Pearlman, The Zone Routing Protocol (ZRP) for Ad Hoc Networks, Internet Draft draft-zone-routing-protocol-01.txt, August 1998; IEEE J. Select. Areas Commun. 17 (8) (1999) 1454]. With the exception of a few, these protocols (i) involve all nodes in the route management process, (ii) rely on the use of broadcast relays for route computation, and (iii) are primarily reactive in nature. Related work [Broch et al., Performance Comparison of Multi-Hop Wireless Ad Hoc Network Routing Protocols, Proceedings of IEEE MOBICOM, Dallas, TX, October 1998; Johansson et al., Scenario-based Performance Analysis of Routing Protocols for Mobile Ad-hoc Networks, Proceedings of IEEE MOBICOM, Seattle, August 1999] has shown that the capacity utilization in ad hoc networks decreases significantly when broadcast relays or "broadcast storms" are performed frequently. This effect is compounded when all nodes in the network take part in the route computation.We propose and study an approach based on overlaying a virtual infrastructure (adaptation of the core, proposed in [IEEE J. Select. Areas Commun. 17 (8) (1999) 1454]) on an ad hoc network and operating routing protocols over the infrastructure. The core enables routing protocols to use only a subset of nodes in the network for route management and avoid the use of broadcast relays. We evaluate the performance of dynamic source routing (DSR) [Broch et al., The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks, Internet Draft draft-ietf-manet-dsr-03.txt, October 1999] and AODV [Perkins et al., Ad Hoc On Demand Distance Vector (AODV) Routing, Internet Draft draft-ietf-manet-aodv-04.txt, October 1999], when they are operated over the core and compare their performances against those of their basic versions. Through extensive simulations using ns-2 [Fall and Vardhan, ns notes and documentation, available from http://www-mash.cs.berkeley.edu/ns/, 1999], we show that using a virtual infrastructure significantly improves the performance of both DSR and AODV, in terms of data delivery and routing overhead, under varied network characteristics.
Merging multiple data streams on common keys over high performance networks
Authors: Marco Mazzucco, Asvin Ananthanarayan, Robert L. Grossman, Jorge Levera, Gokulnath Bhagavantha Rao
Venue: Proceedings of the 2002 ACM/IEEE conference on Supercomputing (2002)

The model for data mining on streaming data assumes that there is a buffer of fixed length and a data stream of infinite length and the challenge is to extract patterns, changes, anomalies, and statistically significant structures by examining the data one time and storing records and derived attributes of length less than N. As data grids, data webs, and semantic webs become more common, mining distributed streaming data will become more and more important. The first step when presented with two or more distributed streams is to merge them using a common key. In this paper, we present two algorithms for merging streaming data using a common key. We also present experimental studies showing these algorithms scale in practice to OC-12 networks.
The Nonlinear Statistics of High-Contrast Patches in Natural Images
Authors: Ann B. Lee, Kim S. Pedersen, David Mumford
Venue: International Journal of Computer Vision (2003)

Recently, there has been a great deal of interest in modeling the non-Gaussian structures of natural images. However, despite the many advances in the direction of sparse coding and multi-resolution analysis, the full probability distribution of pixels values in a neighborhood has not yet been described. In this study, we explore the space of data points representing the values of 3 &times; 3 high-contrast patches from optical and 3D range images. We find that the distribution of data is extremely &ldquo;sparse&rdquo; with the majority of the data points concentrated in clusters and non-linear low-dimensional manifolds. Furthermore, a detailed study of probability densities allows us to systematically distinguish between images of different modalities (optical versus range), which otherwise display similar marginal distributions. Our work indicates the importance of studying the full probability distribution of natural images, not just marginals, and the need to understand the intrinsic dimensionality and nature of the data. We believe that object-like structures in the world and the sensor properties of the probing device generate observations that are concentrated along predictable shapes in state space. Our study of natural image statistics accounts for local geometries (such as edges) in natural scenes, but does not impose such strong assumptions on the data as independent components or sparse coding by linear change of bases.
Formal semantics for interacting UML subsystems
Authors: Jan Jürjens
Venue: Proceedings of the IFIP TC6/WG6.1 Fifth International Conference on Formal Methods for Open Object-Based Distributed Systems V (2002)

So far most work on formal semantics for the Unified Modeling Language (UML) has concentrated on single diagrams. To provide a formal foundation for complete system specifications, one needs to put models for the different diagrams into context. We provide a formal semantics for UML subsystems that incorporates a formal semantics of the diagrams contained in a subsystem. It provides message-passing between objects or components specified in different diagrams, including a dispatching mechanism for events, and the handling of actions. It enables one to compose subsystems from sets of subsystems and allows them to interact by passing messages.We give consistency conditions for the diagrams in a subsystem and define a notion of behavioural equivalence and two kinds of refinement for UML subsystems.
Reconsidering the Philosophical Basis of OR/MS
Authors: Jack R. Meredith
Venue: Operations Research (2001)

Many in Operations Research/Management Science (OR/MS) have long predicted a major contraction in the field. Given the recent trends in OR/MS hiring, this contraction may have finally arrived, both in academia, as well as in industry. This study maintains that part of this contraction is because we drifted from the field's broad, real-world roots due to a limited philosophical foundation of the field, our realist view of reality. If our commonly held realist philosophy has, in the ironic fashion described herein, given rise to the "academic drift" in the field, the recognition of a relativist philosophy that emphasizes understanding over problem solving could help return the field to its roots.
A framework of web-based conceptual design
Authors: S. F. Qin, R. Harrison, A. A. West, I. N. Jordanov, D. K. Wright
Venue: Computers in Industry (2003)

A web-based conceptual design prototype system is presented. The system consists of four parts which interpret on-line sketches as 2D and 3D geometry, extract 3D hierarchical configurations, allow editing of component behaviours, and produce VRML-based behavioural simulations for design verification and web-based application. In the first part, on-line freehand sketched input is interpreted as 2D and 3D geometry, which geometrically represents conceptual design. The system then infers 3D configuration by analysing 3D modelling history. The configuration is described by a parent-child hierarchical relationship and relative positions between two geometric components. The positioning information is computed with respect to the VRML97 specification. In order to verify the conceptual design of a product, the behaviours can be specified interactively on different components. Finally, the system creates VRML97 formatted files for behavioural simulation and collaborative design application over the Internet. The paper gives examples of web-based applications. This work forms a part of a research project into the design and establishing of modular machines for automation manufacture. A consortium of leading automotive companies is collaborating on the research project.
Petri net control for grammar systems
Authors: Maurice ter Beek, Jetty Kleijn
Venue: Formal and natural computing (2002)

It is demonstrated how Petri nets may be used to control the derivations in systems of cooperating grammars. This allows to define grammar systems with a concurrent rewriting protocol. Some basic properties are established.
Value function and necessary conditions in optimal control problems for differential-difference inclusions
Authors: Leonid I. Minchenko, Alexey A. Volosevich
Venue: Nonlinear Analysis: Theory, Methods Applications (2003)

This paper deals with the optimal control problems for differential-difference inclusions subject to endpoint constraints. We follow a twofold goal. First, we develop a method for estimating the generalized gradients of value function in the problems above. Second, we use these estimates for obtaining necessary optimality conditions. The results obtained are expressed in terms of Clarke constructions for nonsmooth mappings and sets.
Predicting the effects of gene deletion
Authors: David S. Vogel, Randy C. Axelrod
Venue: ACM SIGKDD Explorations Newsletter (2002)

In this paper, we describe techniques that can be used to predict the effects of gene deletion. We will focus mainly on the creation of predictive variables, and then briefly discuss different modeling techniques that have been used successfully on this data.
Construction of genomic networks using mutual-information clustering and reversible-jump Markov-chain-Monte-Carlo predictor design
Authors: Xiaobo Zhou, Xiaodong Wang, Edward R. Dougherty
Venue: Signal Processing (2003)

We consider the problem of constructing gene regulatory networks from expression data using the probabilistic-Boolean-network paradigm. We propose to construct the networks according to the following stages. Firstly, we determine the number of possible parent gene sets and the input sets of gene variables corresponding to each gene, and this is done by using a novel clustering technique based on mutual information minimization. Simulated annealing is employed to solve the optimization problem. After such initial gene clustering, we restrict our attention to the class of different functions from the possible parent gene sets to each target gene. Secondly, each function is then modeled by a perceptron consisting of a linear term and a nonlinear term. A reversible-jump Markov-chain-Monte-Carlo (MCMC) technique is used to calculate the model order and the parameters. Finally, the coefficient of determination (CoD) is employed to compute the probability of selecting different predictors for each gene. To test this approach for constructing gene regulatory networks, we have carried out computational experiments using data from known gene response pathways including ionizing radiation and downstream targets of inactivating gene mutations.
Digital partitions encoding
Authors: Joviša Žunić
Venue: Digital and image geometry: advanced lectures (2001)

In this paper we are interested in problems related to the encoding of partitions of discrete sets in Rn with the restriction to the partitions which can be realized by a number of hyperplanes.A particular attention is given to the partitions of subsets of a planar integer grid of a given size, which is a model for a binary picture of a given size.An application of the used encoding method to the encoding of linear threshold functions is given, as well. It turns out, that the obtained O(n2) code is asymptotically optimal with respect to the required memory space.
Effects of broadcast errors on concurrency control in wireless broadcasting environments
Authors: Zakil Koo, Songchun Moon
Venue: Information Processing Letters (2003)

In wireless broadcasting environments, mobile clients cannot receive data reliably over broadcast channels because a reliable transmission protocol is not applicable to the channels. If such broadcast errors are not properly handled by a concurrency control algorithm, it could lead to a fatal effect especially when clients are permitted to issue update transactions. However, the effects of broadcast errors on concurrency control have been little researched. In this paper, we have proposed a concurrency control algorithm to support update transactions issued by mobile clients and evaluated the performance of the algorithm by focusing the effects of broadcast errors with an analytic model. The analytic results show our algorithm is efficient in resolving the broadcast errors.
AT4 family and 2-homogeneous graphs
Authors: Aleksandar Jurišić
Venue: Discrete Mathematics (2003)

Let Γ denote an antipodal distance-regular graph of diameter four, with eigenvalues k = θ0 > θ1 > ... > θ4 and antipodal class size r. Then its Krein parameters satisfy q112 q123 q134 q222 q224 q233 q244 q334 > 0, q122 = q124 = q144 = q223 = q234 = q344 = 0 and q111,q113,q133,q333 ∈ (r - 2)R+. It remains to consider only two more Krein bounds, namely q114 ≥ 0 and q444 ≥ 0. Jurisić and Koolen showed that vanishing of the Krein parameter q114 of Γ implies that Γ is 1-homogeneous in the sense of Nomura, so it is also locally strongly regular. We study vanishing of the Krein parameter q444 of Γ. In this case a well-known result of Cameron et al. implies that Γ is locally strongly regular. We gather some evidence that vanishing of the Krein parameter q444 implies Γ is either triangle-free (in which case it is 1-homogeneous) or the Krein parameter q114 vanishes as well. Then we prove that the vanishing of both Krein parameters q114 and q444 of Γ implies that every second subconstituent graph is again an antipodal distance-regular graph of diameter four. Finally, if Γ is also a double-cover, i.e., r=2, i.e., Q-polynomial, then it is 2-homogeneous in the sense of Nomura.
Zeros and Local Extrema of Trigonometric Sums
Authors: A. A. Karatsuba
Venue: Problems of Information Transmission (2003)

Theorems on the number of zeros and number of local extrema of trigonometric sums, in particular, Gauss and Weyl sums, are proved. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
Challenges of teaching in a small computing department
Authors: Judith Bayard Cushing, Fritz Ruehr, Martin Dwomoh-Tweneboah, Rahul Tikekar
Venue: Journal of Computing Sciences in Colleges (2002)

Teaching in a small computing department (typically 3 or less faculty) has many unique challenges and rewards. CCSC has formed a committee to identify these areas and develop ways to help meet the challenges. The first task of this committee was to develop and distribute a survey to better understand these challenges and rewards. This panel will presents the results of that survey, give their personal perspectives, and discuss the future direction(s) of this work. Feedback from the conference attendees will be very important to the success of this project.
An Efficient Optimistic Message Logging Scheme for Recoverable Mobile Computing Systems
Authors: Taesoon Park, Namyoon Woo, Heon Y. Yeom
Venue: IEEE Transactions on Mobile Computing (2002)

A number of checkpointing and message logging algorithms have been proposed to support fault tolerance of mobile computing systems. However, little attention has been paid to the optimistic message logging scheme. Optimistic logging has a lower failure-free operation cost compared to other logging schemes. It also has a lower failure recovery cost compared to the checkpointing schemes. This paper presents an efficient scheme to implement optimistic logging for the mobile computing environment. In the proposed scheme, the task of logging is assigned to the mobile support station so that volatile logging can be utilized. In addition, to reduce the message overhead, the mobile support station takes care of dependency tracking and the potential dependency between mobile hosts is inferred from the dependency between mobile support stations. The performance of the proposed scheme is evaluated by an extensive simulation study. The results show that the proposed scheme requires a small failure-free overhead and the cost of unnecessary rollback caused by the imprecise dependency is adjustable by properly selecting the logging frequency.
Systems design meets Habermas, Foucault and Latour
Authors: Michael Arnold
Venue: Socio-technical and human cognition elements of information systems (2003)

This chapter begins with a review of the theoretical foundations that are common in the systems design literature, before moving to draw upon the work of three prominent social theorists to analyse and critique a particular case of information systems design. It is argued that in different, but complimentary ways, each theorist offers systems designers compelling insights to guide their work. In particular, it is argued that Habermas' understanding of "Ideal speech"; Foucault's understanding of "power/ knowledge" and "discipline"; and Latour's understanding of systems as "networks"; confirms that social theory is able to offer systems designers concrete recommendations to guide their work.