ppxscal/embedding_network huggingface dataset:
Dimensionality Reduction in Hyperbolic Data Spaces: Bounding Reconstructed-Information Loss
Authors: Duc A. Tran, Khanh Vu
Venue: Proceedings of the Seventh IEEE/ACIS International Conference on Computer and Information Science (icis 2008) (2008)

We have started to see non-Euclidean geometries used in many applications, including visualization, network measurement, and geometric routing. Therefore, we need new mechanisms for managing and exploring non-Euclidean data. In this paper, we specifically address the dimensionality reduction problem for Hyperbolic data that are represented by the Poincare Disk model. A desirable property of our solution is its reconstructed boundedness. In other words, we can reconstruct the data from its dimension-reduced version to obtain an approximation whose deviation from the original data is bounded and independent of the boundary measure of the original data space. We also propose a similarity search technique as an application of our reduction approach. We provide both theoretical and simulation analyses to substantiate the findings of our work.
Experimental observations on nonlinear phenomena in transducer assembly for thermosonic Flip-Chip bonding
Authors: Lei Han, Jue Zhong
Venue: Microelectronic Engineering (2008)

Dynamical characteristics of PZT actuated transducer assembly are the key to reliable flip-chip bonding and basic understanding of metal interconnection. A systematic experimental observations and analysis clearly exhibit that, rich phenomena and effects like the negative cubic stiffness, dynamical coupling between transducer body and tool, velocity dropping and anomalous phase portrait of the die movement, may be explained by nonlinear features and non-parallel loading of transducer assembly onto its bonding area. It will be possible to explore their mechanism and effects to bonding quality by identifying and decoding them.
Geometry is everywhere, part XLVII: metrics, nets, dimensions, and measures
Authors: Kenneth L. Clarkson
Venue: Proceedings of the twenty-fourth annual symposium on Computational geometry (2008)

The idea of a metric space is among the most basic of geometric concepts, and so appears in a great variety of applications and algorithms, sometimes in disguise. For a given metric, the idea of a net, in the general sense of a "collection of nicely distributed points," appears naturally, but there are many conceptions of what it means to be nicely distributed; often this is a function of a parameter ε > 0, which might be for example the minimum distance between pairs of points in the net. For a given version of nets, the idea of dimension appears naturally, as the exponent in the growth rate of nets as a function of ε, while measures on metric spaces give the constant factor in that growth rate. As the parameter ε is varied, the scale of relevant "features" of the metric space changes; that is, variation in ε is a simple form of "multi-resolution analysis." I will survey a little bit of the wealth of variations and implications of these beautiful ideas, both those familiar to the SOCG community and those a little more obscure, with such topics as: the greedy algorithm and other algorithms for building nets; curvature-based metrics; the energy dimension and its relation to random projection; the interplay between continuous concepts and discrete applications; and different versions of multi-resolution.
A note on generalized Euler numbers and polynomials
Authors: C. S. Ryoo, T. Kim, L. C. Jang
Venue: International Journal of Computer Mathematics (2007)

In this paper we construct new generalized Euler polynomials and generalized Euler numbers attached to χ. We investigate some of the properties that are related to generalized Euler polynomials. We also derive the existence of a specific interpolation function that interpolates generalized Euler polynomials at negative integers. Finally, we investigate computationally the roots of the generalized Euler polynomials En, χ(x) for values of the index n.
AN AI ELECTRICAL GROUND SUPPORT EQUIPMENT FOR CONTROLLING AND TESTING A SPACE INSTRUMENT
Authors: María Dolores R-Moreno, Manuel Prieto, Daniel Meziat
Venue: Applied Artificial Intelligence (2007)

A versatile and modular electrical ground support equipment (EGSE) system has been developed using artificial intelligence (AI) techniques to control and test the PESCA instrument and the communication process of the satellite without any human supervision. The PESCA instrument has been designed and built with the purpose of studying solar energetic particles and the anomalous cosmic rays. It will be part of the Russian FOTON satellite payload that is scheduled to be launched in December 2007. The tool allows complete and autonomous control, verification, and validation of the PESCA instrument, although its modularity makes it extensible to other onboard instruments.
Missing Value Estimation for Time Series Microarray Data Using Linear Dynamical Systems Modeling
Authors: Connie Phong, Raul Singh
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

The analysis of gene expression time series obtained from microarray experiments can be effectively exploited to understand a wide range of biological phenomena from the homeostatic dynamics of cell cycle systems to the response of key genes to the onset of cancer or infectious disease. However, microarray data frequently contain a significant number of missing values making the application of common multivariate analysis methods, all of which require complete expression matrices, difficult. In order to preserve the experimentally expensive non-missing data points in time series gene expression data, methods are needed to estimate the missing values in such a way that preserves the latent interdependencies among time points within individual expression profiles. Thus we propose modeling gene expression profiles as simple linear and Gaussian dynamical systems and apply the Kalman filter to estimate missing values. While other current advanced estimation methods are either sensitive to parameters with no theoretical means of selection or attempt to learn statically from inherently dynamical data, our approach is advantageous exactly because it makes minimal assumptions that are consistent with the biology. We demonstrate the efficiency of our approach by evaluating its performance in estimating artificially introduced missing values in two different time series data sets, and compare it to a Bayesian approach dependent on the eigenvectors of the gene expression matrix as well as a gene wise average imputation for missing values.
Bringing into register incomplete range images of cultural artifacts
Authors: Joanna Tworzydło, Krzysztof Skabek, Leszek Luchowski, Ryszard Winiarczyk
Venue: Machine Graphics Vision International Journal (2006)

Finding solutions for preserving cultural heritage and historic and architectural sites as 3D models is an important problem in our days. Building 3D models of real objects is also an important research issue in virtual reality. Since a 3D range scanner, used to obtain 3D data, is a line-of-sight instrument, in most cases it is necessary to scan the object from multiple viewpoints to completely reconstruct it. The acquired range images need to be brought into register to build one coherent model. This article presents two registration methods for incomplete range images. One is based on the assumption that the range images being registered have a significant overlap with some feature points. The second one needs additional 2D photographs of the scene to perform the right registration, but the overlapping area of the range images is not necessary here. The presented methods are semi-automatic and base on the analysis of redundant and uncertain data.
Dynamic redundancy resolution in a nonholonomic wheeled mobile manipulator
Authors: Glenn d. White, Rajankumar m. Bhatt, Venkat n. Krovi
Venue: Robotica (2007)

Wheeled Mobile Manipulators (WMM) possess many advantages over fixed-base counterparts in terms of improved workspace, mobility and robustness. However, the combination of the nonholonomic constraints with the inherent redundancy limits effective exploitation of end-effector payload manipulation capabilities. The dynamic-level redundancy-resolution scheme presented in this paper decomposes the system dynamics into decoupled task-space (end-effector motions/forces) and a dynamically consistent null-space (internal motions/forces) component. This simplifies the subsequent development of a prioritized task-space control (of end-effector interactions) and a decoupled but secondary null-space control (of internal motions) in a hierarchical WMM controller. Various aspects of the ensuing novel capabilities are illustrated using a series of simulation results.
E-Government Policy and Health Information Systems Implementation in Andhra Pradesh, India: Need for Articulation of Linkages Between the Macro and the Micro
Authors: Shirin Madon, Sundeep Sahay, Randeep Sudan
Venue: The Information Society (2007)

In recent years, many different types of e-government projects have been implemented across the developing world. One important application area, especially following the Millennium Development Goals, is the introduction of health information systems to improve the management of health care for development. Despite significant investments in these projects, experience reveals a disjuncture between macro-level policy priorities and micro-level implementation of these programmes. We use a broad conceptualization of evaluation to synthesize priorities at different levels during the implementation of an e-government project-the Health Information Systems Project (HISP) in Andhra Pradesh, India. This enables us to identify important enabling processes and conditions which serve to connect policy and implementation priorities. Our findings suggest that evaluation does help us to understand the disjuncture between policy at the macro level and implementation at the micro level and to identify linkages between the two. Finally, we discuss some of the key institutional issues that need to be addressed to translate the learning derived from the field into policy actions.
Estimation of pith position in untreated log ends in sawmill environments
Authors: Kristin Norell, Gunilla Borgefors
Venue: Computers and Electronics in Agriculture (2008)

Two related methods for automatic estimation of the pith position, i.e., the centre of the annual rings, in wood log end face images are presented. We use images that depict untreated log end faces that are deliberately chosen to include difficulties such as rot, non-circular shape, uncentered pith and dirt. The images are taken with a regular digital camera in sawmill environments. Both presented methods use local orientation and Hough transform to detect the pith position, but two different ways to compute the local orientation are used. The results are promising for both methods. At least one of the methods is fast enough to use on-line at a sawmill.
Parallelization of a grid-oriented model on the example of a biogenic volatile organic compounds emission model
Authors: Gerhard Smiatek
Venue: Environmental Modelling Software (2008)

A general fast parallelization approach of a grid-oriented model is described on the example of the semi-empirical biogenic volatile compound (BVOC) emission model (seBVOC). It uses distributed memory parallel (DMP) model relying on the MPI (message passing interface) library. The parallel version achieves nearly linear decrease in execution time as the number of processors is increased. However, with some numbers of processors the efficiency suffers from unequal load balance caused by different number of calculations within the grid cells. Application of variable domain decomposition improves the load balance adding up to 35% additional decrease of processing time.
Exploiting Redundancies to Improve Performance of LT Decoding
Authors: Hillary Tarus, John Bush, James Irvine, John Dunlop
Venue: Proceedings of the Communication Networks and Services Research Conference (2008)

Rateless codes are a class of codes without a predefined number of encoding symbols. Fountain codes are the first such codes. Luby Transform codes, designed by Michael Luby, are examples of these codes. The accepted and efficient decoding algorithm for these dense bipartite codes is the belief propagation (BP) algorithm as opposed to Gaussian elimination algorithm. LT codes are more efficient as the number of symbols grow. However for streaming purposes, the number of source symbols needs to be constrained while at the same time the probability of success be maintained. In this paper we propose a BP decoding enhancement algorithm using redundancies in the already received encoding symbols to improve the probability of performance of LT decoding. We show that in the limit our proposal achieves upto 15% performance improvement in decoding throughput with similar channel conditions. We emulate our proposal in software and the results follow that predicted by theoretical analysis.
Introduction to Geometric Computing, 1 edition
Authors: Sherif Ghali
Venue:  (2008)

Although geometry has been a flourishing discipline for millennia, most of it has seen either no practical applications or only esoteric ones. Computing is quickly making much of geometry intriguing not only for philosophers and mathematicians, but also for scientists and engineers. What is the core set of topics that a practitioner needs to study before embarking on the design and implementation of a geometric system in a specialized discipline? This book attempts to find the answer. Every programmer tackling a geometric computing problem encounters design decisions that need to be solved. What may not be clear to individual programmers is that these design decisions have already been contemplated by others who have gone down some system design path only to discover (usually much later) that the design decisions that were made were lacking in some respect. This book reviews the geometric theory then applies it in an attempt to find that elusive right design.
The teaching of novice computer programmers: bringing the scholarly-research approach to Australia
Authors: Tony Clear, Jenny Edwards, Raymond Lister, Beth Simon, Errol Thompson, Jacqueline Whalley
Venue: Proceedings of the tenth conference on Australasian computing education - Volume 78 (2008)

BRACElet is a multi-institutional multi-national research study of how novice programmers comprehend and write computer programs. This paper reviews the first action research cycle of the BRACElet project and, in the process, charts a path for the upcoming second cycle. The project remains close to educational practice, with much of the data being either data collected directly from exams sat by novices, or data from think-out-loud protocols where the task undertaken by a novice or an expert is modelled on an exam question. The first action research cycle analysed data in terms of the SOLO taxonomy. From think-aloud responses, the authors found that educators tended to manifest a SOLO relational response on small reading problems, whereas students tended to manifest a multistructural response. Furthermore, those students who manifested a relational response tended to do better overall in the exam than students who manifested a multistructural response. The second action research cycle will explore the relationship between the ability to read code and the ability to write code. Apart from reporting on the BRACElet project itself, this paper serves as an invitation for institutions and individuals to join the second action research cycle of the BRACElet project.
Security Enforcement Model for Distributed Usage Control
Authors: Xinwen Zhang, Jean-Pierre Seifert, Ravi Sandhu
Venue: Proceedings of the 2008 IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing (sutc 2008) (2008)

Recently proposed usage control concept and models extend traditional access control models with features for contemporary distributed computing systems, including continuous access control in dynamic computing environments where subject attributes and system states can be changed. Particularly, this is very useful in specifying security requirements to control the usage of an object after it is released into a distributed environment, which is regarded as one of the fundamental security issues in many distributed systems. However, the enabling technology for usage control is a challenging problem and the space has not been fully explored yet. In this paper we identify the general requirements of a trusted usage control enforcement in heterogeneous computing environments, and then propose a general platform architecture and enforcement mechanism by following these requirements. According to our usage control requirements, we augment the traditional SELinux MAC enforcement mechanism by considering subject/object integrity and environmental information. The result shows that our framework is effective in practice and can be seen as a general solution for usage control in distributed and pervasive computing environments with widely deployed trusted computing technologies on various computing devices.
Visualizing Product Line Domain Variability by Aspect-Oriented Modeling
Authors: Reinhard Stoiber, Silvio Meier, Martin Glinz
Venue: Proceedings of the Second International Workshop on Requirements Engineering Visualization (2007)

Modeling variability is a core problem in software product line engineering. The relationship between variability and commonality in a software product line bears strong similarities to the relationship between crosscutting concerns and core concerns in aspectoriented modeling. So modeling variability with aspect- oriented techniques is an obvious idea which has been exploited before to some extent. In this paper, we propose a new approach to modeling and visualizing variability by a combination of aspect-oriented variability modeling with table-based modeling of configuration possibilities and constraints. As a modeling language, we use a slightly extended version of the ADORA language. Our main contributions are a visual, integrated model comprising both the commonality and the variability of the product line and a novel mechanism for synthesizing products from this model based on the aspect weaving capabilities of ADORA.
A perspective on marine wireless sensor networks
Authors: Ahmed Mahdy
Venue: Journal of Computing Sciences in Colleges (2008)

Despite the rapid growth of wireless sensor networks in the last few years, research on marine wireless sensor networks has been minimal. Basic and applied research on the development of these unique sensor networks is greatly needed. This paper presents a perspective on the development of marine wireless sensor networks. The current research and development of wireless sensor networks are based on the assumption that these networks are deployed in a land environment. Relevant protocols and design specifications are developed under this condition. This makes the deployment of currently existing wireless sensor networks in marine environments extremely challenging. New techniques and algorithms are needed to achieve this goal. The objective of this paper is to study the unique characteristics and major challenges imposed on the development of novel marine wireless sensor networks. This will open the door for a wide range of applications as well as new areas of relevant research in wireless networks.
Matching graphs
Authors: Linda Eroh, Michelle Schultz
Venue: Journal of Graph Theory (1998)

The matching graph M(G) of a graph G is that graph whose vertices are the maximum matchings in G and where two vertices M1 and M2 of M(G) are adjacent if and only if |M1 - M2| = 1. When M(G) is connected, this graph models a metric space whose metric is defined on the set of maximum matchings in G. Which graphs are matching graphs of some graph is not known in general. We determine several forbidden induced subgraphs of matching graphs and add even cycles to the list of known matching graphs. In another direction, we study the behavior of sequences of iterated matching graphs. &copy; 1998 John Wiley & Sons, Inc. J. Graph Theory 29: 73&ndash;86, 1998
Compressed Index for Dictionary Matching
Authors: Wing-Kai Hon, Tak-Wah Lam, Rahul Shah, Siu-Lung Tam, Jeffrey Scott Vitter
Venue: Proceedings of the Data Compression Conference (2008)

The past few years have witnessed several exciting results on compressed representation of a string T that supports efficient pattern matching, and the space complexity has been reduced to |T|H_k(T) + o(|T| log s) bits, where H_k(T) denotes the kth-order empirical entropy of T, and s is the size of the alphabet. In this paper, we study compressed representation of another classical problem of string indexing, which is called dictionary matching in the literature. Precisely, a collection D of strings (called patterns) of total length n is to be indexed so that given a text T, the occurrences of the patterns in T can be found efficiently. In this paper we show how to exploit a sampling technique to compress the existing O(n)-word index to an (nH_k(D) + o(n log s))-bit index with only a small sacrifice in search time.
Divergence and Power Variations in Mobile Free-Space Optical Communications
Authors: Alan Harris, Tayeb Giuma
Venue: Proceedings of the Third International Conference on Systems (2008)

Free-space optical (FSO) communications links are envisioned as a viable option for the provision of temporary high-bandwidth communications links between mobile platforms. The introduction of mobility to a technology originally intended for fixed communications links introduces several interesting challenges. Two of those challenges are the variation in receiver beam profile of the FSO link and variation in received optical power due to the constantly changing transmitter-receiver separation. This paper investigates how the provision of mobile communications using FSO technology is challenged by beam divergence and optical power levels. An analytical model of the receiver beam profile of a mobile FSO link is presented, along with simulation results of both beam profile and optical power levels for a temporary mobile FSO communications link.
On the density and discrepancy of a 2D point set with applications to thermal analysis of VLSI chips
Authors: Subhashis Majumder, Bhargab B. Bhattacharya
Venue: Information Processing Letters (2008)

In this era of giga-scale integration, thermal analysis has become one of the hot topics in VLSI chip design. Active thermal sources may be abstracted as a set of weighted points on a 2D chip-floor. The conventional notion of discrepancy that deals with the congestion properties of a set of scattered points may not be able to capture properly all real-life instances in this context. In this paper, we have introduced a new concept, called the density of a region to study some of the properties of the distribution of these weighted points. We prove several counter-intuitive results concerning the properties of the regions that have maximum or minimum density. We then outline algorithms for recognizing these regions. We also compare the attributes of density with the existing concept of discrepancy.