ppxscal/embedding_network huggingface dataset:
The absolute center of a network: Dedicated to the memory of Jonathan Halpern 1940&ndash;1981
Venue: Networks (2004)

This paper presents a new algorithm for finding an absolute center &lpar;minimax criterion&rpar; of an undirected network with n nodes and m arcs based on the concept of minimum-diameter trees. Local centers and their associated radii are identified by a monotonically increasing sequence of lower bounds on the radii. Computational efficiency is addressed in terms of worst-case complexity and practical performance. The complexity of the algorithm is 0&lpar;n2 &ell;g n &plus; mn&rpar;. In practice, because of its very rapid convergence, the algorithm renders the problem amenable even to manual solution for quite large networks, provided that the minimal-distance matrix is given. Otherwise, evaluation of this matrix is the effective computational bottleneck. An interesting feature of the algorithm and its theoretical foundations is that it synthesizes and generalizes some well-known results in this area, particularly Halpern's lower bound on the local radius of a network and properties of centers of tree networks. &copy; 2004 Wiley Periodicals, Inc.
A new approach to risk estimation in many-criteria automatic control systems. I
Authors: L. V. Zhukovskaya
Venue: Automation and Remote Control (2005)

A new approach to decision making in automatic control systems under risk is designed, in which the performance quality of the system is estimated by several criteria with known variation ranges of uncertain factors and unknown statistical characteristics. A formalization procedure for the guaranteed solution is designed and its existence under the usual constraints (of game theory) is demonstrated. This paper borders on the works [1, 2].
Valiant's model and the cost of computing integers
Authors: Pascal Koiran
Venue: Computational Complexity (2005)

Let ¿(n) be the minimum number of arithmetic operations required to build the integer $$n \in \mathbb{N}$$ from the constants 1 and 2. A sequence xn is said to be "easy to compute" if there exists a polynomial p such that $$\tau (x_n ) \leq p(\log n)$$ for all It is natural to conjecture that sequences such as $$\left\lfloor {2^n \ln 2} \right\rfloor $$ or n! are not easy to compute. In this paper we show that a proof of this conjecture for the first sequence would imply a superpolynomial lower bound for the arithmetic circuit size of the permanent polynomial. For the second sequence, a proof would imply a superpolynomial lower bound for the permanent or P ¿ PSPACE.
Book reivew: ARTIFICIAL INTELLIGENCE IN ECONOMICS AND MANAGEMENT. Edited by L. P. Pau (North-Holland 1986)
Venue: Issue 102 (October 1987) (1987)

This book is a collection of thirty-three of the papers written after the International Workshop on Al in Economics and Management, which was held March 12 - 14, 1985, in Zurich, Switzerland. The main sponsor was the International Federation of Automatic Control, with multiple co-sponsors (ACM, IEEE-CS, IFORS, IFIP, ECCAI, etc.). Being a collection of thirty-three papers spread out over 288 pages (plus xv), the papers are necessarily short: the shortest is four pages and the longest is eighteen pages, although the latter has one page of references and seven pages of figures. Seventeen of the papers are seven, eight, or nine pages in length; of the remaining sixteen, eight are shorter and eight are longer.
A COTS Component Comprehension Process
Authors: Anneliese A. Andrews, Andreas Stefik, Nina Picone, Sudipto Ghosh
Venue: Proceedings of the 13th International Workshop on Program Comprehension (2005)

A process is proposed to support comprehension of COTS components. In this process, software developers build a COTS comprehension model to support component selection. We integrate the process with a UML component based software development approach. We illustrate our approach using a hotel reservation system.
An analytical model for software-only main memory compression
Authors: Irina Chihaia, Thomas Gross
Venue: Proceedings of the 3rd workshop on Memory performance issues: in conjunction with the 31st international symposium on computer architecture (2004)

Many applications with large data spaces that cannot run on a typical workstation (due to page faults) call for techniques to expand the effective memory size. One such technique is memory compression.Understanding what applications under what conditions can benefit from main memory compression is complicated due to various tradeoffs and the dynamic characteristics of applications. For instance, a large area to store compressed data increases the effective memory size considerably but also decreases the amount of memory that can hold uncompressed data.This paper presents an analytical model that states the conditions for a compressed-memory system to yield performance improvements. Parameters of the model are the compression algorithm efficiency, the amount of data being compressed, and the application memory access pattern. Such a model can be used by an operating system to compute the size of the compressed-memory level that can improve an application's performance.
A New Authentication and Key Exchange Protocol in WLAN
Authors: Chen Zhuo, Hong Fan, Hong Liang
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume II - Volume 02 (2005)

The security of identity authentication and key negotiate is an important foundation of WLAN (Wireless Local Area Network) security. We present a new authentication and key exchange protocol Wireless Key Exchange (WKE) using for WLAN. The BAN logic is used to formalize and prove the security of WKE at the same time. At last we combine the WKE and Diffie-Hellman exchange to accomplish key negotiate in Mobile IP for WLAN.
Tree decompositions with small cost
Authors: Hans L. Bodlaender, Fedor V. Fomin
Venue: Discrete Applied Mathematics (2005)

The f-cost of a tree decomposition ({Xi | i ∈ I}, T = (I, F)) for a function f : N → R+ is defined as Σi∈I f(|Xi|). This measure associates with the running time or memory use of some algorithms that use the tree decomposition. In this paper, we investigate the problem to find tree decompositions of minimum f-cost. A function f: N → R+ is fast, if for every i ∈ N: f(i + 1) ≥ 2 f(i). We show that for fast functions f, every graph G has a tree decomposition of minimum f-cost that corresponds to a minimal triangulation of G; if f is not fast, this does not hold. We give polynomial time algorithms for the problem, assuming f is a fast function, for graphs that have a polynomial number of minimal separators, for graphs of treewidth at most two, and for cographs, and show that the problem is NP-hard for bipartite graphs and for cobipartite graphs. We also discuss results for a weighted variant of the problem derived of an application from probabilistic networks.
Amplifying reflective thinking in musical performance
Authors: Andrew Johnston, Shigeki Amitani, Ernest Edmonds
Venue: Proceedings of the 5th conference on Creativity cognition (2005)

In this paper we report on the development of tools that encourage both a creative and reflective approach to music-making and musical skill development. A theoretical approach to musical skill development is outlined and previous work in the area of music visualisation is discussed. In addition the characterisation of music performance as a type of design problem is discussed and the implications of this position for the design of tools for musicians are outlined. Prototype tools, the design of which is informed by the theories and previous work, are described and some preliminary evaluation of their effectiveness is discussed.Future directions are outlined.
Using Prime Numbers for Cache Indexing to Eliminate Conflict Misses
Authors: Mazen Kharbutli, Keith Irwin, Yan Solihin, Jaejin Lee
Venue: Proceedings of the 10th International Symposium on High Performance Computer Architecture (2004)

Using alternative cache indexing/hashing functions is a popular technique to reduce conflict misses by achieving a more uniform cache access distribution across the sets in the cache. Although various alternative hashing functions have been demonstrated to eliminate the worst case conflict behavior, no study has really analyzed the pathological behavior of such hashing functions that often result in performance slowdown. In this paper, we present an in-depth analysis of the pathological behavior of cache hashing functions. Based on the analysis, we propose two new hashing functions: prime modulo and prime displacement that are resistant to pathological behavior and yet are able to eliminate the worst case conflict behavior in the L2 cache. We show that these two schemes can be implemented in fast hardware using a set of narrow add operations, with negligible fragmentation in the L2 cache. We evaluate the schemes on 23 memory intensive applications. For applications that have non-uniform cache accesses, both prime modulo and prime displacement hashing achieve an average speedup of 1.27 compared to traditional hashing, without slowing down any of the 23 benchmarks. We also evaluate using multiple prime displacement hashing functions in conjunction with a skewed associative L2 cache. The skewed associative cache achieves a better average speedup at the cost of some pathological behavior that slows down four applications by up to 7%.
Combining light animation with obscurances for glossy environments: Research Articles
Authors: Àlex Méndez-Feliu, Mateu Sbert
Venue: Computer Animation and Virtual Worlds (2004)

Obscurances is a powerful technique that approximates indirect global illumination in a much faster way than classic methods as radiosity or path tracing. In this method, the local environment of a point or a patch is sampled to estimate the amount of occlusion that surrounds it. Fine effects as color reflection can be added and visually pleasant rendering of corners and soft shadows are easily computed. Combined with ray tracing techniques, non-diffuse and specular effects can be added to the surfaces, obtaining thus beautiful and realistic rendered images. Since direct and indirect illumination are decoupled, obscurances are very useful to render animation frames for moving light sources, as they have to be computed only for the first frame and then reused. Ambient light intensity can also be decoupled from obscurances and estimated for every frame, resulting in beautiful color-changing effects. Light animation help in light design and to convey shape and features of the objects in the scene. Copyright &copy; 2004 John Wiley & Sons, Ltd.
Communities of reflection-practice and clash of communities: thoughts on the (re-)design of classes in humanities
Authors: Johannes Strobel
Venue: ACM SIGGROUP Bulletin (2003)

Grounded in constructivist instructional philosophy [5] and a view that the purpose of schooling is to prepare students for a changing workplace [7; Partnership for 21st Century Skills, www.21stcenturyskills.org], learning scientists turned to communities of practice (CoPs) to get inspiration for the design of learning activities in classrooms that resemble the 'authentic' and 'real-world' situations found in CoPs outside of schools. For domains that are naturally close to the workforce, like domains in the sciences, technology, engineering, math, and others, it seems a perfect match and classroom environments are transformed to resemble CoPs [4; 6; 9].
Construction of Power-Aware Diameter-Reduced Broadcast Trees
Authors: S. Veeravalli, Laxmi Gewali, V. Muthukumar
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume II - Volume 02 (2005)

Constructing a power aware broadcast tree is a central problem in sensor network. The problem of constructing a power minimized broadcast tree in a sensor network is known to be NP-Hard. Known approximation algorithms for constructing power reduced broadcast trees may have large diameter which are not suitable for reducing transmission error. In this paper a modification of the standard BIP algorithm called P-BIP that can be used to generate power-reduced broadcast trees with small diameter is presented. The proposed algorithm has been implemented and tested using a java based simulation tool.
Combining bundle search with buyer coalition formation in electronic markets: a distributed approach through explicit negotiation
Authors: Linli He, Thomas R. Ioerger
Venue: Proceedings of the 6th international conference on Electronic commerce (2004)

In electronic markets, both bundle search and buyer coalition formation are profitable purchasing strategies for buyers who need to buy small amount of goods and have no bargaining power. It is valuable to combine these two purchasing strategies for buyers to obtain greater discounts based on the different discount policies of multiple sellers. In this paper, we present a distributed mechanism that allows buyers to use both purchasing strategies. The mechanism includes a very efficient heuristic bundle search algorithm and a distributed coalition formation scheme, which is based on an explicit negotiation protocol. The resulting coalitions are stable in the core. The simulation results show that the cost to buyers is close to the optimal cost. Increasing the number of buyers who are involved in the coalition formation process does not increase the communication load caused by the negotiation between two buyers.
Exploring Price and Product Information Search Behavior in e-Market
Authors: Taedong Han
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume I - Volume 01 (2005)

Many have expected that the increased availability of price and product information over a wide range of vendors and low search costs on the Web would increase price competition, reduce price dispersion, and eventually lower the level of product price. However, recent empirical studies have shown somewhat conflicting results. Price dispersion still exists in many online industries even for commodities like books and CDs. This research explores the reason behind consumer search behavior on the Web. The results of this study show that consumers in emarket do not search for either price or product information, even with low search costs, as much as we have anticipated. The results also indicate that the traditional consumer segmentation in the physical market may not always apply in the e-market. In terms of price and product information searches, brand loyalists showed higher search activity than other e-consumer groups unlike in physical market.
A neural network approach to interference mechanism for logic programming language
Authors: Yuji Takeda, Hideya Kawahara, Yukihiro Kikuchi, Hideki Murakoshi, Noboru Funakubo
Venue: Systems and Computers in Japan (2004)

It is known that the Hopfield-type neural network can solve the combinatorial optimization problem with a high speed. In order to realize that advantage, however, the energy function must be constructed for each problem, and there is no general framework to be applied to various problems. This paper notes that the logic programming language Prolog can be represented as the logical operation of facts and the rules, and proposes an algorithm, which converts the logical operation network to the Hopfield-type neural network. Using this conversion algorithm, the power of the Hopfield-type network as an optimization machine can be utilized in the logic inference described by Prolog. Then, it is expected that the range of its application will be enlarged greatly. &copy; 2004 Wiley Periodicals, Inc. Syst Comp Jpn, 35(13): 63&ndash;70, 2004; Published online in Wiley InterScience (). DOI 10.1002&sol;scj.10102
Review of "Proceedings of the 1988 Connectionist Models Summer School by David Touretzky, Geoffrey Hinton and Terrence Sejnowski", Morgan Kaufmann Publishers, 1989.
Authors: Paul McKevitt
Venue: ACM SIGART Bulletin (1998)

Here we have a set of papers by a number of researchers (students and faculty) at the time of the revival of connectionism, and some of the students have since made their names in the field (e.g., Bookman, Miikkulainen, and Regier). The proceedings is from the second Connectionist Models Summer School held at Carnegie Mellon University in 1988 and organized by Dave Touretzky with Geoffrey Hinton and Terrence Sejnowski as advisors.
Subscription-enhanced content delivery
Authors: Mao Chen, Jaswinder Pal Singh, Andrea LaPaugh
Venue: Web content caching and distribution: proceedings of the 8th international workshop (2004)

In existing content delivery systems user accesses are popularly used for predicting the request pattern of contents. In novel web applications such as publish/subscribe services, users explicitly provide statements of interest in the form of subscriptions. These subscriptions provide another source of user information in addition to access patterns. This paper addresses the content delivery problem when user-stated interest is available. Each request by a user is either based on a notification about the availability of content that matches the user's subscriptions, or general browsing that is not based on the publish/subscribe service. We propose two approaches to content delivery that exploit both proactive push-time placement and passive access-time replacement based on the subscription information, the access pattern of subscribers, and that of non-subscribers. In our simulation-based evaluation, the two approaches are compared to an access-based caching only algorithm and to three approaches that were proposed for pure notification-driven accesses in our earlier study [5]. The results demonstrate that incorporating subscription information judiciously can substantially reduce the response time, even when only a small portion of accesses is driven by notifications and the subscription information does not reflect subscribers' accesses perfectly. To our knowledge, this work is the first effort to investigate general content delivery and caching enhanced by using subscription information.
A model for short-term content adaptation
Authors: Marco Benini, Alberto Trombetta, Michela Acquaviva
Venue: Special interest tracks and posters of the 14th international conference on World Wide Web (2005)

This paper proposes a model for short-term content adaptation whose aim is to satisfy the contingent needs of users by adjusting the information a web-application provides on the basis of a short-term user profile. The mathematical model results in the design of an adaptive filter that profiles users by observing their queries to the application and that adjusts the answers of the application according to the inferred user needs. Also, the mathematical model ensures the correctness of the filter, that is, the filter is guaranteed to exhibit a coherent short-term adaptive behaviour.
QoS-Based Authentication Scheme for Ad Hoc Wireless Networks
Authors: P. Muppala, Johnson Thomas, Ajith Abraham
Venue: Proceedings of the International Conference on Information Technology: Coding and Computing (ITCC'05) - Volume II - Volume 02 (2005)

In this paper we investigate the selection of an optimal threshold level that takes into account security and quality of service requirements for ad hoc networks. We incorporate intelligence into the selection of an optimal threshold for a distributed threshold cryptography scheme for a distributed trust model in ad hoc networks. We investigate both local and global threshold schemes.
J-Sim: A Simulation Environment for Wireless Sensor Networks
Authors: Ahmed Sobeih, Wei-Peng Chen, Jennifer C. Hou, Lu-Chuan Kung, Ning Li, Hyuk Lim, Hung-Ying Tyan, Honghai Zhang
Venue: Proceedings of the 38th annual Symposium on Simulation (2005)

Wireless Sensor Networks (WSNs) have gained considerable attention in the past few years. As such, there has been an increasing need for defining and developing simulation frameworks for carrying out high-fidelity WSN simulation. In this paper, we present a modeling and simulation framework for WSNs in J-Sim ¿ an open-source, component-based compositional network simulation environment that is developed entirely in Java. This framework is built upon the autonomous component architecture (ACA) and the extensible internetworking framework (INET) of J-Sim, and provides an object-oriented definition of (i) target, sensor and sink nodes, (ii) sensor and wireless communication channels, and (iii) physical media such as seismic channels, mobility model and power model (both energy-producing and energy-consuming components). Application-specific models can be defined by sub-classing classes in the simulation framework and customizing their behaviors. We demonstrate the use of the proposed WSN simulation framework by implementing several well-known localization, geographic routing, and directed diffusion protocols. In addition, we perform performance comparisons (in terms of execution time incurred, and the memory used) in simulating several typical WSN scenarios in J-Sim and ns-2. The simulation study indicates that the proposed WSN simulation framework in J-Sim is much more scalable than ns-2 (especially in memory usage).
Time Accurate Unsteady Simulation of the Stall Inception Process in the Compression System of a US Army Helicopter Gas Turbine Engine
Authors: Michael D. Hathaway, Greg Herrick, Jenping Chen, Robert Webster
Venue: Proceedings of the 2004 Users Group Conference (2004)

The operational envelope of gas turbine engines such as those employed in the Army Blackhawk helicopter is constrained by the stability limit of the compression system. Technologies developed to improve the stable operating range of gas turbine compressors lack a fundamental understanding beneficial to design guidance. Improved understanding of the stall inception process and how stall control technologies mitigate such will provide compressors with increased tolerance to stall, thereby expanding the operational envelope of military gas turbine engines. Compressors which consist of multiple stages of stationary and rotating blade rows can include shocks, vortices, separations, secondary flows, shock/boundary layer interactions, and turbulent wakes, all of which grow in severity as a compressor approaches stall. As a compressor nears stall the flow field is no longer periodic from passage to passage so all blade passages must be computed. For a typical multistage compressor this becomes a formidable computational challenge requiring access to massively parallel machines in order to meet the computational and memory demands of the problem. We are using a time-accurate CFD code to simulate the unsteady stall inception process, both with and without stall control technology, in the compression system of the T700 engine which is employed in the Army Blackhawk Helicopter. This work will provide the first-ever 3-dimensional viscous time-accurate simulation of the stall inception process in a multistage compressor, providing insight into the causal link between compressor blade design parameters and the stable operating limit, which will be used to guide new design practices leading to compressor designs with increased tolerance to stall. This paper presents progress to date on this DoD Challenge Project.