ppxscal/embedding_network huggingface dataset:
On the complexity of nash dynamics and sink equilibria
Authors: Vahab S. Mirrokni, Alexander Skopalik
Venue: Proceedings of the tenth ACM conference on Electronic commerce (2009)

Studying Nash dynamics is an important approach for analyzing the outcome of games with repeated selfish behavior of self-interested agents. Sink equilibria has been introduced by Goemans, Mirrokni, and Vetta for studying social cost on Nash dynamics over pure strategies in games. However, they do not address the complexity of sink equilibria in these games. Recently, Fabrikant and Papadimitriou initiated the study of the complexity of Nash dynamics in two classes of games. In order to completely understand the complexity of Nash dynamics in a variety of games, we study the following three questions for various games: (i) given a state in game, can we verify if this state is in a sink equilibrium or not? (ii) given an instance of a game, can we verify if there exists any sink equilibrium other than pure Nash equilibria? and (iii) given an instance of a game, can we verify if there exists a pure Nash equilibrium (i.e, a sink equilibrium with one state)? In this paper, we almost answer all of the above questions for a variety of classes of games with succinct representation, including anonymous games, player-specific and weighted congestion games, valid-utility games, and two-sided market games. In particular, for most of these problems, we show that (i) it is PSPACE-hard to verify if a given state is in a sink equilibrium, (ii) it is NP-hard to verify if there exists a pure Nash equilibrium in the game or not, (iii) it is PSPACE-hard to verify if there exists any sink equilibrium other than pure Nash equilibria. To solve these problems, we illustrate general techniques that could be used to answer similar questions in other classes of games.
A visual query language for large spatial databases
Authors: Andrew J Morris, Alia I. Abdelmoty, Baher A. El-Geresy
Venue: Proceedings of the working conference on Advanced visual interfaces (2002)

In this paper a visual approach to querying in large spatial databases is presented. A diagrammatic technique utilising a data flow metaphor is used to express different kinds of spatial and non-spatial constraints. Basic filters are designed to represent the various types of queries in such systems. Icons for different types of spatial relations are used to denote the filters. Different granularities of the relations are presented in a hierarchical fashion when selecting the spatial constraints. Spatial joins and composite spatial and non-spatial constraints are represented consistently in the language.
Impact of Presentation Format and Self-Reported Risk Aversion on Revealed Skewness Preferences
Authors: Dennis Vrecko, Alexander Klos, Thomas Langer
Venue: Decision Analysis (2009)

This paper reports the results of an experiment on the revealed preference for skewness in a comparison of continuous return distributions. We find that revealed preferences are highly sensitive to the way asset risks are communicated. Whereas probability density functions lead to a pronounced preference for left-skewed distributions, the opposite is true for cumulative distribution functions. Systematic misperceptions of the variance cannot explain the sensitivity of preferences to the presentation format. Part of the preference for positive skewness when risks are communicated through probability density functions is due to a systematic misestimation of the expected return. We also find that self-reported risk aversion, a measure of risk attitude commonly used in practice, is a valuable predictor of skewness preferences. Individuals that judge themselves as more risk averse show a stronger preference for right skewness.
A calculus approach to energy-efficient data transmission with quality-of-service constraints
Authors: Murtaza A. Zafer, Eytan Modiano
Venue: IEEE/ACM Transactions on Networking (TON) (2009)

Transmission rate adaptation in wireless devices provides a unique opportunity to trade off data service rate with energy consumption. In this paper, we study optimal rate control to minimize transmission energy expenditure subject to strict deadline or other quality-of-service (QoS) constraints. Specifically, the system consists of a wireless transmitter with controllable transmission rate and with strict QoS constraints on data transmission. The goal is to obtain a rate-control policy that minimizes the total transmission energy expenditure while ensuring that the QoS constraints are met. Using a novel formulation based on cumulative curves methodology, we obtain the optimal transmission policy and show that it has a simple and appealing graphical visualization. Utilizing the optimal "offline" results, we then develop an online transmission policy for an arbitrary stream of packet arrivals and deadline constraints, and show, via simulations, that it is significantly more energy-efficient than a simple head-of-line drain policy. Finally, we generalize the optimal policy results to the case of time-varying power-rate functions.
Plenary lecture 3: the fuzzy-interpolative adaptive controllers
Authors: Marius M. Balas
Venue: Proceedings of the 10th WSEAS international conference on Fuzzy systems (2009)

The lecture is discussing the fundamental sides of the fuzzy sets: the interpolative one. Since any fuzzy controller can be approximated by a corresponding interpolative one, the linear interpolations can be fully applied in almost any fuzzy sets application. The fuzzy-interpolative controllers are fuzzy controllers that may be equaled with linear interpolative networks. They are alloying the advantages of the linguistic representation of knowledge offered by the fuzzy side with the easiness of the interpolative implementations. Some applications focused on adaptive control and expert systems are presented.
Modeling user submission strategies on production grids
Authors: Diane Lingrand, Johan Montagnat, Tristan Glatard
Venue: Proceedings of the 18th ACM international symposium on High performance distributed computing (2009)

Production-grid users experience many system faults as well as high and variable latencies due to the scale, complexity and sharing of such infrastructures. To improve performance, they adopt different submission strategies, that are potentially aggressive for the infrastructure. This work studies the impact of three different strategies. It is based on a probabilistic modeling of these strategies which are evaluated according to their performance, measured as the reduction of the latency expectation, and the infrastructure overhead, measured as the additional number of submitted jobs. A strategy cost criterion is then derived. Experiments are performed using real workload traces collected from the EGEE production infrastructure. Under these conditions, a good balance between high performance and low overhead can be found.
Optical Code Division Multiple Access Communication Networks: Theory and Applications, 1st edition
Authors: Hongxi Yin, David J. Richardson
Venue:  (2009)

Optical code division multiple access (OCDMA) communication network technology will play an important role in future optical networks, such as optical access and metropolitan area networks. OCDMA technology can also be appliedto implementoptical signal multiplexing and label switching on backbone networks. Optical Code Division Multiple Access Communication Networks - Theory and Applications introduces the code theory of OCDMA, the methods and technologies of OCDMA encoding and decoding, the theory and methods of analyzing OCDMA systems with various receiver models and realizing multiple-class services with different bit rates and QoS. In addition, OCDMA network architectures, protocols and applications are discussed in detail. The up-to-date theoretical and experimental results on OCDMA systems and networks are also reported. A large number of encoding/decoding examples and many analysis and simulation results of code and system performances are given. It is a valuable text and/or reference book for postgraduates majoring in telecommunication and photonics to obtain a well-knit theoretical foundation and for engineers in R&D and management of optical communications. Dr. Yin is an Associate Professor of the School of Electronics Engineering and Computer Science at Peking University, China, and was a Visiting Research Fellow of Optoelectronics Research Centre (ORC) at University of Southampton, UK. Dr. Richardson is a Professor for optical communications and Deputy Director of ORC at University of Southampton, UK, and is responsible for much of the ORC's fiber related activities.
A semi-automatic system for managing multiple digital preservation risks of digital libraries in china
Authors: Chao Li, Chunxiao Xing, Li Dong, Michael Bailou Huang
Venue: Proceedings of the 9th ACM/IEEE-CS joint conference on Digital libraries (2009)

While many research projects in the world have been addressing challenges posed by digital preservation, digital libraries in China have their own native problems that have never been addressed before. Similar problems may occur in other countries, and their memory institutions may be less prepared to handle them. This poster analyses the requirements and challenges of digital libraries in China and describes an integrated and flexible digital preservation system -- AOMS.
Performance and Computational Complexity Comparison of Block-Based Fingerprint Enhancement
Authors: Suksan Jirachaweng, Teesid Leelasawassuk, Vutipong Areekul
Venue: Proceedings of the Third International Conference on Advances in Biometrics (2009)

Performance and computational complexity comparisons of various block-based fingerprint enhancement schemes are tested and reported in this literature. Enhancement performance is evaluated by comparing equal error rates, which obtained by a proposed fingerprint matching algorithm using local and global features. Various enhancement methods are tested; i.e. three types of spatial Gabor filtering, short-time Fourier transform filtering, and discrete cosine transform filtering. These enhancement schemes also tested with various databases such as FVC2000, FVC2002, and FVC2004. Finally, computational complexity of enhancement implementation is analyzed and concluded.
Matching Trajectories of Anatomical Landmarks Under Viewpoint, Anthropometric and Temporal Transforms
Authors: Alexei Gritai, Yaser Sheikh, Cen Rao, Mubarak Shah
Venue: International Journal of Computer Vision (2009)

An approach is presented to match imaged trajectories of anatomical landmarks (e.g. hands, shoulders and feet) using semantic correspondences between human bodies. These correspondences are used to provide geometric constraints for matching actions observed from different viewpoints and performed at different rates by actors of differing anthropometric proportions. The fact that the human body has approximate anthropometric proportion allows innovative use of the machinery of epipolar geometry to provide constraints for analyzing actions performed by people of different sizes, while ensuring that changes in viewpoint do not affect matching. In addition, for linear time warps, a novel measure, constructed only from image measurements of the locations of anatomical landmarks across time, is proposed to ensure that similar actions performed at different rates are accurately matched as well. An additional feature of this new measure is that two actions from cameras moving at constant (and possibly different) velocities can also be matched. Finally, we describe how dynamic time warping can be used in conjunction with the proposed measure to match actions in the presence of nonlinear time warps. We demonstrate the versatility of our algorithm in a number of challenging sequences and applications, and report quantitative evaluation of the matching approach presented.
AD-SVMs: A light extension of SVMs for multicategory classification
Authors: Ricardo Ñanculef, Carlos Concha, Héctor Allende, Diego Candel, Claudio Moraga
Venue: International Journal of Hybrid Intelligent Systems (2009)

The margin maximization principle implemented by binary Support Vector Machines (SVMs) has been shown to be equivalent to find the hyperplane equidistant to the closest points belonging to the convex hulls that enclose each class of examples. In this paper, we propose an extension of SVMs for multicategory classification which generalizes this geometric formulation. The obtained method preserves the form and complexity of the binary case, optimizing a single convex quadratic program where each new class introduces just one additional constraint. Reduced convex hulls and non-linear kernels, used in the binary case to deal with the non-linearly separable case, can be also implemented by our algorithm to obtain additional flexibility. Experimental results in well known datasets are presented, comparing our method with two widely used multicategory SVMs extensions.
Critical Thinking Environments for Science Education
Authors: Beverly Park Woolf, Tom Murray, David Marshall, Toby Dragon, Kevin Kohler, Matt Mattingly, Merle Bruno, Dan Murray, Jim Sammons
Venue: Proceeding of the 2005 conference on Artificial Intelligence in Education: Supporting Learning through Intelligent and Socially Informed Technology (2005)

We have developed a range of critical thinking environments for science education that span several academic content areas, including human biology, geology and forestry. All environments share a methodology, infrastructure and sets of assumptions and tools, which allows them to leverage from the accomplishments and intuitions of the others. These tutors support a student on the Web to be active and engaged, track that student's critical thinking and reason about her knowledge and its own teaching strategies. An Inquiry Notebook provides a way to sort, filter and categorize data and justifications and an Argument Editor supports argument formation. Students drag and drop evidence to support or refute each argument. A Coach provides helpful feedback guided by a database of expert rules, which create the basis for the content-specific analysis of the student's argument.
A Heuristic Approach to Fragmentation Incorporating Query Information
Authors: Hui Ma, Klaus-Dieter Schewe, Markus Kirchberg
Venue: Proceeding of the 2007 conference on Databases and Information Systems IV: Selected Papers from the Seventh International Baltic Conference DB&IS'2006 (2007)

Fragmentation and allocation are database distribution design techniques used to improve the system performance by increasing data localisation and reducing data transportation costs between different network sites. Often fragmentation and allocation are considered separately, disregarding that they are using the same input information to achieve the same objective. Vertical fragmentation is often considered a complicated problem, because the huge number of alternatives make it nearly impossible to obtain an optimal solution. Therefore, many researchers seek for heuristic solutions, among which affinity-based vertical fragmentation approaches form a main stream in the literature. However, using attribute affinities to perform fragmentation can not really reflect the local needs of data at each site. Therefore it is not guaranteed that the remote data transportation costs can be reduced. This paper addresses vertical fragmentation and allocation simultaneously in the context of the relational data model. The core of the paper is a heuristic approach to vertical fragmentation, which uses a cost model and is targeted at globally minimising these costs. Further, based on the proposed vertical fragmentation, an integrated methodology is proposed by applying vertical and horizontal fragmentation simultaneously to produce mixed fragmentation schemata.
Quick evaluation of small body gravitation
Authors: Anil N. Hirani
Venue:  (2008)

Numerical integration of ordinary differential equations resulting from the gravitation of nearby celestial small bodies is the subject of this thesis. We present three methods that alleviate the computational burden of evaluating gravitational force near a small body: (i) adaptive polynomial interpolation, (ii) adaptive polynomial least squares approximation, and (iii) acceleration via specialized, commodity hardware. Each method is evaluated on its quantitative accuracy with respect to a reference model, and its observance of qualitative features of gravity. We conclude with a summary of methods available for computing small body gravitation, and recommendations for different scenarios.
Evaluation of online strategies for reordering buffers
Authors: Matthias Englert, Heiko Röglin, Matthias Westermann
Venue: Journal of Experimental Algorithmics (JEA) (2009)

A sequence of objects that are characterized by their color has to be processed. Their processing order influences how efficiently they can be processed: Each color change between two consecutive objects produces costs. A reordering buffer, which is a random access buffer with storage capacity for k objects, can be used to rearrange this sequence online in such a way that the total costs are reduced. This concept is useful for many applications in computer science and economics. The strategy with the best-known competitive ratio is MAP. An upper bound of O(log k) on the competitive ratio of MAP is known and a nonconstant lower bound on the competitive ratio is not known. Based on theoretical considerations and experimental evaluations, we give strong evidence that the previously used proof techniques are not suitable to show an o(&sqrt;log k) upper bound on the competitive ratio of MAP. However, we also give some evidence that in fact MAP achieves a competitive ratio of O(1). Further, we evaluate the performance of several strategies on random input sequences experimentally. MAP and its variants RC and RR clearly outperform the other strategies FIFO, LRU, and MCF. In particular, MAP, RC, and RR are the only known strategies whose competitive ratios do not depend on the buffer size. Furthermore, MAP achieves the smallest competitive ratio.
Technology Neutral Business Process Design using URDAD
Authors: Fritz Solms
Venue: Proceeding of the 2007 conference on New Trends in Software Methodologies, Tools and Techniques: Proceedings of the sixth SoMeT_07 (2007)

This paper presents the Use Case, Responsibility Driven Analysis and Design methodology, URDAD. URDAD aims to provide a simple algorithmic design methodology which generates a technology neutral business process design in the context of model driven development. The design methodology has been formulated in such a way that it includes core drivers for widely accepted requirements for good design.
Formal analysis of the kerberos authentication protocol
Authors: Andre Scedrov
Venue:  (2008)

The security of cryptographic protocols has traditionally been verified with respect to one of two mathematical models: One, known as the Dolev-Yao or symbolic model, abstracts cryptographic concepts into an algebra of symbolic messages. Methods based on the Dolev-Yao abstraction, which make use of simple formal languages or logics, have been successfully applied to discover structural flaws in numerous cryptographic protocols, and have also become efficient and robust enough to tackle large commercial protocols, often even automatically. The other, known as the computational or cryptographic model, retains the concrete view of messages as bitstrings and cryptographic operations as algorithmic mappings between bitstrings, while drawing security definitions from complexity theory. Proofs in the computational approach entail strong security guarantees, however, only simple cryptographic protocols, mainly of academic interest, have been verified with respect to the computational model.This dissertation contributes to the ongoing case study of the Kerberos 5 protocol suite, a widely used authentication protocol. We report on a man-in-the-middle attack on PKINIT, the public key extension of Kerberos, which allows an attacker to impersonate Kerberos administrative principals (KDC) and end-servers to a client and also gives the attacker the keys that the KDC would normally generate to encrypt the service requests of this client, hence defeating authentication and confidentiality guarantees of Kerberos. We have formally verified several possible fixes to PKINIT that prevent our attack using the symbolic Multiset Rewriting formalism. We also present proofs of the full Kerberos 5 suite with and without its public-key extension for the first time in the more detailed Dolev-Yao dialect of the BPW model. These proofs may be used to gain computationally sound results. Furthermore, we present a computationally sound mechanized analysis of Kerberos 5, both with and without its public-key extension PKINIT, using the prover CryptoVerif, which works directly in the computational model. We obtain proofs of authentication and key secrecy properties that are the first mechanical proofs of a full industrial protocol at the computational level. We generalize the notion of key usability, which, although weaker than the standard notion of key indistinguishability, guarantees under certain assumptions that a key can be securely used for cryptographic operations, and show that this definition is satisfied by keys in Kerberos.
X3D earth terrain-tile production chain for georeferenced simulation
Authors: Byounghyun Yoo, Don Brutzman
Venue: Proceedings of the 14th International Conference on 3D Web Technology (2009)

Broad needs for digital models of real environments such as 3D terrain or cyber cities are increasing. Many applications related to modeling and simulation require virtual environments constructed from real-world geospatial information in order to guarantee relevance and accuracy in the simulation. The most fundamental data for building virtual environments, terrain elevation and orthogonal imagery, is typically acquired using optical sensors mounted on satellites or airplanes. Providing interoperable and reusable digital models in 3D is important for promoting practical applications of high-resolution airborne imagery. This paper presents research results regarding virtual-environment representations of geospatial information, especially for 3D shape and appearance of virtual terrain. It describes a framework for constructing real-time 3D models of large terrain based on highresolution satellite imagery. This approach is also suitable for underwater bathymetry. The Extensible 3D Graphics (X3D) Geospatial Component standard is applied to produce X3D Earth models with global scope. Efficient rendering, network retrieval and data caching/removal must all be optimized simultaneously, across servers, networks and clients, in order to accomplish these goals properly. Details of this standard-based approach for providing an infrastructure for real-time 3D simulation merging high-resolution geometry and imagery are also presented. This work facilitates open interchange and interoperability across diverse simulation systems and is independently usable by governments, industry, scientists and the general public.