ppxscal/embedding_network huggingface dataset:
Estimating the size of the transitive closure in linear time
Authors: E. Cohen
Venue: Proceedings of the 35th Annual Symposium on Foundations of Computer Science (1994)

Computing transitive closure and reachability information in directed graphs is a fundamental graph problem with many applications. The fastest known algorithms run in O(sm) time for computing all nodes reachable from each of 1/spl les/s/spl les/n source nodes, or, using fast matrix multiplication, in O(n/sup 2.38/) time for computing the transitive closure, where n is the number of nodes and m the number of edges in the graph. In query optimization in database applications it is often the case that only estimates on the size of the transitive closure and on the number of nodes reachable from certain nodes are needed. We present an O(m) time randomized algorithm that estimates the number of nodes reachable from every node and the size of the transitive closure. We also obtain a O/spl tilde/(m) time algorithm for estimating sizes of neighborhoods in directed graphs with nonnegative weights, avoiding the O/spl tilde/(mn) time bound of explicitly computing these neighborhoods. Our size-estimation algorithms are much faster than performing the actual computations and improve significantly over previous estimation methods.
A study of land cover classification using polarimetric SAR parameters
Authors: V. Alberga
Venue: International Journal of Remote Sensing (2007)

Classification of the Earth's surface constitutes an important application of polarimetric synthetic aperture radar (SAR) data; in turn, it may represent an efficient way for investigating their different representations. The polarimetric parameters most frequently taken into account for classification have been the incoherent ones. A similar use of coherent methods appears to have been scarcely considered and remained neglected. In this contribution, we wish to address this issue, testing and comparing a wide range of polarimetric SAR parameters, coherent and incoherent. Another original aspect of this work is the study of the dependence of the classification results on the varying size of averaging windows of pixels. Such an analysis will permit us to evaluate the importance of speckle reduction and to prove if the chosen polarimetric parameters describe only point-like physical properties of the targets or if they also contain 'extended', local information. The goal is to provide an objective estimate of the quality of the classification of polarimetric parameters and afford their comparison, an exercise hitherto unavailable in the literature in common knowledge.
Remembering William Goffman: Mathematical information science pioneer
Authors: Glynn Harmon
Venue: Information Processing and Management: an International Journal (2008)

This paper reviews the career and legacy of William (Bill) Goffman, who served as a researcher, Professor, Dean and Emeritus at Case Western Reserve University, Cleveland, Ohio, from 1959 to 2000. Goffman pioneered mathematical information science broadly and in several key areas. First, he applied disease epidemiology concepts to model accurately the spread of knowledge and the formation of knowledge systems and their ecologies, including the dynamics of scientific discovery. Second, he proposed significant improvements in information retrieval through the deployment of multi-valued logic, appropriate file ordering, effective and efficient retrieval measures, and simplified retrieval approaches, including early work in citation-based searching. Third, Goffman applied Bradford-like distributions to model effective core research literature collection development and usage. Fourth, he developed original epidemiology models, and was an early contributor in biomedical informatics. His mathematical contributions have stood the test of time and will continue to be applicable indefinitely.
Constructing Formally Verified Reasoners for the ALC Description Logic
Authors: M. J. Hidalgo, J. A. Alonso, F. J. Martín, J. L. Ruiz
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

Description Logics are a family of logics used to represent and reason about conceptual and terminological knowledge. Recently, its importance has been increased since they are used as a basis for the Ontology Web Language (OWL) used for the Semantic Web. In previous work, we have developed in PVS a generic framework for reasoning in the ALC description logic, proving its termination, soundness and completeness. In this paper we present the construction, from the generic framework, of a formally verified generic tableau-based algorithm for checking satisfiability of ALC-concepts. We do it using a methodology of refinements to transfer the properties from the framework to the algorithm. We also obtain some verified reasoners from the algorithm by a process of instantiation.
Reading Efficiency of Chinese Text Scrolling Style and Presentation Style on Computer Interface
Authors: Xue-min Zhang, Heng-sheng Zhang, Yang Bin, Di-fan Zhang, Renlai Zhou
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

The present research studied the effects of page scrolling style, reading task and column on the efficiency of text reading from a monitor. The results indicated that participants could finish their reading task more quickly when the task was information search than when it was reading comprehension and that they read texts more efficiently in one-column format than in two-column format. However, concerning the page-scrolling style, participants finished information search task more quickly in scrolling-by-line style while the opposite occurred when the task was reading comprehension.
Analysis of mechanical interaction between human gluteal soft tissue and body supports
Authors: C. Then, J. Menger, G. Benderoth, M. Alizadeh, T. J. Vogl, F. Hübner, G. Silber
Venue: Technology and Health Care (2008)

Pressure sores are the most common complication associated with patient immobilization. They develop through sustained localized tissue strain and stress, primarily caused by body supports. Modifying support design can reduce the risk and extent of pressure sore development with computational simulations helping to provide insight into tissue stress-strain distribution. Appropriate material parameters for human soft tissue and support material, as well as precise anatomical modelling, are indispensable in this process. A finite element (FE) model of the human gluteal region based on magnetic resonance imaging (MRI) data has been developed. In vivo human gluteal skin/fat and muscle long-term material parameters as well as open-cell polyurethane foam support long-term material parameters have been characterised. The Ogden form for slightly compressible materials was employed to describe human gluteal soft tissue behaviour. Altering support geometries and support materials, effects on human gluteal soft tissue could be quantified. FE-analysis indicated maximal tissue stress at the muscle-bone interface, not at the skin. Shear strain maxima were found in the muscle layer near the fat-muscle interface. Maximum compressive stress magnitude at the sacral bone depended strongly on the behaviour of the pelvic diaphragm musculature. We hypothesize that the compliance of the muscles forming the pelvic diaphragm govern the relative motion of the buttock tissue to the adjacent bone structure under compression, thus influencing tissue stress magnitudes.
On approximation of infinite-dimensional quantum channels
Authors: M. E. Shirokov, A. S. Holevo
Venue: Problems of Information Transmission (2008)

We develop an approximation approach to infinite-dimensional quantum channels based on a detailed investigation of continuity properties of entropic characteristics of quantum channels and operations (trace-nonincreasing completely positive maps) as functions of a pair "channel, input state." Obtained results are then applied to the problems of continuity of the ¿-capacity as a function of a channel, strong additivity of the ¿-capacity for infinite-dimensional channels, and approximating representation for the convex closure of the output entropy of an arbitrary quantum channel.
Effective Pólya semi-positivity for non-negative polynomials on the simplex
Authors: Hoi-Nam Mok, Wing-Keung To
Venue: Journal of Complexity (2008)

We consider homogeneous polynomials f@?R[x"1,...,x"n] which are non-negative on the standard simplex in R^n, and we obtain sufficient conditions for such an f to be Polya semi-positive, that is, all the coefficients of (x"1+...+x"n)^Nf are non-negative for all sufficiently large positive integers N. Such sufficient conditions are expressed in terms of the vanishing orders of the monomial terms of f along the faces of the simplex. Our result also gives effective estimates on N under such conditions. Moreover, we also show that any Polya semi-positive polynomial necessarily satisfies a slightly weaker condition. In particular, our results lead to a simple characterization of the Polya semi-positive polynomials in the low dimensional case when n=
Hierarchical Average Reward Reinforcement Learning
Authors: Mohammad Ghavamzadeh, Sridhar Mahadevan
Venue: The Journal of Machine Learning Research (2007)

Hierarchical reinforcement learning (HRL) is a general framework for scaling reinforcement learning (RL) to problems with large state and action spaces by using the task (or action) structure to restrict the space of policies. Prior work in HRL including HAMs, options, MAXQ, and PHAMs has been limited to the discrete-time discounted reward semi-Markov decision process (SMDP) model. The average reward optimality criterion has been recognized to be more appropriate for a wide class of continuing tasks than the discounted framework. Although average reward RL has been studied for decades, prior work has been largely limited to flat policy representations. In this paper, we develop a framework for HRL based on the average reward optimality criterion. We investigate two formulations of HRL based on the average reward SMDP model, both for discrete-time and continuous-time. These formulations correspond to two notions of optimality that have been previously explored in HRL: hierarchical optimality and recursive optimality. We present algorithms that learn to find hierarchically and recursively optimal average reward policies under discrete-time and continuous-time average reward SMDP models. We use two automated guided vehicle (AGV) scheduling tasks as experimental testbeds to study the empirical performance of the proposed algorithms. The first problem is a relatively simple AGV scheduling task, in which the hierarchically and recursively optimal policies are different. We compare the proposed algorithms with three other HRL methods, including a hierarchically optimal discounted reward algorithm and a recursively optimal discounted reward algorithm on this problem. The second problem is a larger AGV scheduling task. We model this problem using both discrete-time and continuous-time models. We use a hierarchical task decomposition in which the hierarchically and recursively optimal policies are the same for this problem. We compare the performance of the proposed algorithms with a hierarchically optimal discounted reward algorithm and a recursively optimal discounted reward algorithm, as well as a non-hierarchical average reward algorithm. The results show that the proposed hierarchical average reward algorithms converge to the same performance as their discounted reward counterparts.
GrafiXML, a Multi-target User Interface Builder Based on UsiXML
Authors: Benjamin Michotte, Jean Vanderdonckt
Venue: Proceedings of the Fourth International Conference on Autonomic and Autonomous Systems (2008)

We have developed GrafiXML, an original user interface builder in that it enables designers and developers to design several UIs simultaneously for multiple contexts of use, i.e. for many users, platforms, and environments. For this purpose, it maintains coordination between three representations: an internal representation consisting of specifications in USer Interface eXtensible Markup Language (UsiXML), an external representation consisting of the interface preview, and a conceptual representation consisting of a user interface model. GrafiXML is an intelligent UI builder in that it maintains model consistency between these representations through a set of mappings based on a user interface ontology. Thanks to this mechanism, GrafiXML provides a unique set of features for supporting designing interfaces for multiple targets. These features are defined, motivated, discussed, and exemplified on a simple interface. Then, it is explained how the UI resulting from this design can support one or many levels of independence with respect to the underlying context of use.
SRPTES: A Secure Routing Protocol Based on Token Escrow Set for Ad Hoc Networks
Authors: Chen Huang, Benxiong Huang, Yijun Mo, Jianhua Ma
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

Ad hoc networks, which do not rely on fixed infrastructure such as base stations, can be deployed rapidly and inexpensively in situations with geographical or time constraints. However, the nature of Ad hoc networks makes them vulnerable to attacks, especially in routing protocols. In order to establish a secure route composed only by trusted nodes and prevent routes from being tampered by internal malicious nodes, we present a novel Secure Routing Protocol based on Token Escrow Set (SRPTES). SRPTES employs token with limited lifetime to control the trust relationships between neighboring nodes, and provides secure routing and packet forwarding services through valid token. As the core of SRPTES, it creates completely distributed and localized Token Escrow Set (TES) which can maintain robust trust relationships among nodes and greatly reduce the overhead of key management. The simulation results show that SRPTES provides an effective security enhancement and improves the efficiency of routing establishment in insecure environment.
How to denest Ramanujan's nested radicals
Authors: J. Blomer
Venue: Proceedings of the 33rd Annual Symposium on Foundations of Computer Science (1992)

The author presents a simple condition when nested radical expressions of depth two can be denested using real radicals or radicals of some bounded degree. He describes the structure of these denestings and determines an upper bound on the maximum size of a denesting. Also for depth two radicals he describes an algorithm that will find such a denesting whenever one exists. Unlike all previous denesting algorithms the algorithm does not use Galois theory. In particular, he avoids the construction of the minimal polynomial and splitting field of a nested radical expression. Thus he can obtain the first denesting algorithm whose run time is at most, and in general much less, than polynomial in description size of the minimal polynomial. The algorithm can be used to determine non-trivial denestings for expressions of depth larger than two.
Acquisition of visited locative nouns from blogs by using surface features of blogs and case frames
Authors: Takuya Kobayashi, Masatoshi Yoshikawa
Venue: Proceedings of the 2nd international conference on Ubiquitous information management and communication (2008)

Extraction of reputation information from blog content has recently been emerging as an important research topic. In case of reputation about planimetrical features such as facilities or restaurants, documents not based on actual visits are unsuitable as the extracted objects for reputation information. This paper proposes a method of acquiring visited locative nouns from blog documents by using their surface features and case frames. We expect that the extraction of information from blogs with a higher degree of certainty will be possible by applying this method before extracting reputation information.
Soundscape composition as global music: Electroacoustic music as soundscape*
Authors: Barry Truax
Venue: Organised Sound (2008)

The author covers the background of soundscape composition, as initiated by the World Soundscape Project at Simon Fraser University, and soundscape documentation as an activity that is being increasingly practised worldwide. Today there are two striking manifestations of this work: the increasing globalisation of the electroacoustic community, and the increasing sophistication of digital techniques applied to soundscape composition. In addition, the tradition of listening to environmental soundscapes as if they were music is inverted to suggest listening to electroacoustic music as if it were soundscape. What analytical tools and insights would result? The theoretical concepts introduced in soundscape studies and acoustic communication are summarised and applied first to media and digital gaming environments, noting the extensions of both their sound worlds and the related listening attitudes they provoke in terms of analytical and distracted listening. Traditional approaches to acousmatic and soundscape analysis are compared for their commonalities and differences, the latter being mainly their relative balance of attention towards inner and outer complexity. The types of electroacoustic music most amenable to a soundscape based analysis are suggested, along with brief examples of pieces to which such analysis might be directed.
Analyzing memory access intensity in parallel programs on multicore
Authors: Lixia Liu, Zhiyuan Li, Ahmed H. Sameh
Venue: Proceedings of the 22nd annual international conference on Supercomputing (2008)

As the shared memory bus becomes a major performance bottleneck for many numerical applications on multicore chips, understanding how the increased parallelism on chip strains the memory bandwidth and hence affects the efficiency of parallel codes becomes a critical issue. This paper introduces the notion of memory access intensity to facilitate quantitative analysis of program's memory behavior on multicores which employ state-of-the-art prefetching hardware. Three numerical solvers for large scale sparse linear systems are used to demonstrate the estimation of memory access intensity and its effect on program performance.
Poster abstract: force-based geometric routing
Authors: Cong Liu, Jie Wu
Venue: Proceedings of the 9th ACM international symposium on Mobile ad hoc networking and computing (2008)

Routing is the foremost issue in mobile ad hoc networks (MANETs) and sensor networks. To guarantee delivery and improve performance, most position-based routing protocols are based on face routing, which requires the underlying network to be a planar graph. Localized planar graph construction requires the radio model to be a unit disk graph and it is only applicable to two-dimensional networks. This paper presents an efficient force-based geometric routing algorithm which is applicable to general network models and has a worst-case bound for arbitrary three-dimensional networks.
Optimization of the Quine-McCluskey Method for the Minimization of the Boolean Expressions
Authors: Tarun Kumar Jain, D. S. Kushwaha, A. K. Misra
Venue: Proceedings of the Fourth International Conference on Autonomic and Autonomous Systems (2008)

The basic principle in designing digital circuit hovers around reducing the required hardware thus reducing the cost too. To achieve this, we use Boolean expression that helps in obtaining minimum number of terms and does not contain any redundant pairs. The conventional methods for the minimization of the Boolean expressions are K-Map method and the Tabulation method. The minimized expressions are used to design digital circuits. Since K-Map method gets exceedingly complex when the number of the variable exceed six, hence Quine-McCluskey tabulation method scores over this and is widely used. In the following paper we present optimized Quine-McCluskey method that reduces the run time complexity of the algorithm by proposing an efficient algorithm for determination of Prime Implicants
Turtle's navigation and manipulation of geometrical figures constructed by variable processes in a 3d simulated space
Authors: Chronis Kynigos, Maria Latsi
Venue: Informatics in education (2007)

Issues related to 3d turtle's navigation and geometrical figures' manipulation in the simulated 3d space of a newly developed computational environment, MaLT, are reported and discussed here. The joint use of meaningful formalism and the dynamic manipulation of graphically represented 3d figures seem to offer new resources and to pose new challenges as far as geometrical activities and construction of meanings are concerned, which are strongly related to the representational infrastructure of MaLT. Abilities such as spatial orientation and spatial visualisation come into play and are interwoven with the software's functionalities and semantics. Although the body-syntonic metaphor remains critical while navigating the turtle in the 3d simulated space, it seems that it has to be co-ordinated with other - often conflicting one another - frames of reference. The strong link between spatial graphical and geometrical aspects, that was accentuated by the dragging functionalities of the software, helped students go beyond an immediate perceptual approach, relating geometrical figures with real 3d objects and the change of planes in 3d space with physical angle situations. In this framework the concept of angle as turn and measure with emphasis on directionality but also as a relationship between the planes defined by 2d figures has arisen as central.
On holomorphic L2 functions on coverings of strongly pseudoconvex manifolds
Authors: Alexander Brudnyi
Venue: Publications of the Research Institute for Mathematical Sciences (2007)

In this paper we answer an important question posed in the paper [GHS] by Gromov, Henkin and Shubin on existence of sufficiently many holomorphic L2 functions on arbitrary coverings of strongly pseudoconvex manifolds.
Monolithic silicon optocoupler engineering based on tapered waveguides
Authors: K. Misiakos, E. Makarona, M. Kitsara, I. Raptis
Venue: Microelectronic Engineering (2008)

The increased need for further miniaturization of biosensors poses an increased need for the integrated optical fibers to bend, fold or change direction within the biosensor chip. In this work, we explore the effect tapering brings to the coupling efficiency of fibers both theoretically and experimentally. In addition, we also explore and discuss the role of the cladding materials into the efficient stirring of light in conjunction with the tapering geometries used in this study.