ppxscal/embedding_network huggingface dataset:
Efficient Semantic Based Search in Unstructured Peer-to-Peer Networks
Authors: Hoda Mashayekhi, Jafar Habibi, Habib Rostami
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

Peer-to-peer networks have gained a tremendous popularity in sharing huge volumes of data. Success of such networks highly depends on the performance of their search algorithm. We propose a semantic based search algorithm for unstructured peer-to-peer networks. In the proposed method we establish ontology based indexes for outgoing links of each node, which are utilized in routing the query through the network. In contrast to available approaches, we maintain limited size indexes and also consider number of documents accessible via each link and the distance between source and destination nodes, to improve the accuracy and efficiency of our algorithm. Our design is scalable and adaptable, to satisfy the requirements of dynamic peer-to-peer networks. We show that the proposed search method performs well whether the requested object is a popular or rare concept. Our technique is simple in design and implementation. We simulate our algorithm on an unstructured peer to peer network and show that while preserving the quality of search results, it significantly reduces network traffic in comparison to randomized routing scheme.
An experimental study of cooperative learning in cs1
Authors: Leland L. Beck, Alexander W. Chizhik
Venue: Proceedings of the 39th SIGCSE technical symposium on Computer science education (2008)

An experiment was conducted to study the effectiveness of the cooperative learning approach to teaching CS1. The cooperative learning exercises, which used specific roles to focus students' attention on key concepts, were designed so they could be used in a variety of educational settings. Experimental results show that the benefits of cooperative learning clearly outweighed any possible losses due to reduced lecture time. These benefits were enjoyed by both male and female students, and by students from a variety of majors. Majority and minority students performed at approximately the same overall level when using the cooperative learning approach. There are indications that the educational benefits continue when students who had a cooperative learning experience in CS1 go on to CS2.
On the second largest eigenvalue of line graphs
Authors: Miroslav Petrović, Bojana Milekić
Venue: Journal of Graph Theory (1998)

In this paper all connected line graphs whose second largest eigenvalue does not exceed 1 are characterized. Besides, all minimal line graphs with second largest eigenvalue greater than 1 are determined. &copy; 1998 John Wiley & Sons, Inc. J Graph Theory 27: 61&ndash;66, 1998
Backups to the future: eliminate tape backups with freeNAS and bacula
Authors: Jeramiah Bowling
Venue: Linux Journal (2008)

Lose the tapes. Embrace the disk.
On the complexity of kinodynamic planning
Authors: J. Canny
Venue: Proceedings of the 29th Annual Symposium on Foundations of Computer Science (1988)

The following problem, is considered: given a robot system find a minimal-time trajectory from a start position and velocity to a goal position and velocity, while avoiding obstacles and respecting dynamic constraints on velocity and acceleration. The simplified case of a point mass under Newtonian mechanics together with velocity and acceleration bounds is considered. The point must be flown from a start to a goal, amid 2-D or 3-D polyhedral obstacles. While exact solutions to this problem are not known, the first provably good approximation algorithm is given and shown to run in polynomial time.
Approximate retrieval of XML data with ApproXPath
Authors: Lin Xu, Curtis Dyreson
Venue: Proceedings of the nineteenth conference on Australasian database - Volume 75 (2008)

Several XML query languages have been proposed that use XPath expressions to locate data. But XPath expressions might miss some data because of irregularities in the data and schema of an XML data collection. In this paper we propose ApproXPath, which supports approximate path expressions. Approximate path expressions have the same syntax as XPath expressions, but allow content and structural errors. An error is a string or tree edit operation that creates a (virtual) data collection in which the data can be located. ApproXPath extends XPath's axes, node tests and predicates to utilize the string/tree edit distance. We show that the complexity of ApproXPath is reasonable. For many queries, the inexact matching (with no errors) is as fast as exact matching, and the cost increases linearly with the number of errors allowed.
Notes on design of transformation-based reduced-rank generalized sidelobe canceller for matrix LCMV filter
Authors: Zhi Li, Hong Ma, Enbin Song
Venue: Signal Processing (2008)

This paper is concerned with the design of transformation-based reduced-rank generalized sidelobe canceller (RRGSC) for the linearly constrained minimum variance (LCMV) filter. Most RRGSCs introduced in the previous literature were limited to vector form, and their performances were not compared with the LCMV filter. In order to overcome these drawbacks, we present a detailed discussion about the relationship between the general matrix LCMV filter and the transformation-based RRGSC, and obtain several new results. First, we study the effect of transformation matrix on the performance of RRGSC, and find the optimal design of the transformation matrix that can minimize the performance loss of RRGSC relative to the LCMV filter. Second, we obtain a sufficient and necessary condition for the performance equivalence between RRGSC and LCMV filter. Third, we obtain the minimum loss-free reduced-rank of RRGSC, and formulate the relationship between the reduced-rank and the minimum performance loss of RRGSC relative to LCMV filter. Application cases and computer simulations are provided to demonstrate the usefulness and correctness of the above-mentioned theoretical results.
Identification of time-varying objects on the web
Authors: Satoshi Oyama, Kenichi Shirasuna, Katsumi Tanaka
Venue: Proceedings of the 8th ACM/IEEE-CS joint conference on Digital libraries (2008)

We have developed a method for determining whether data found on the Web are for the same or different objects that takes into account the possibility of changes in their attribute values over time. Specifically, we estimate the probability that observed data were generated for the same object that has undergone changes in its attribute values over time and the probability that the data are for different objects, and we define similarities between observed data using these probabilities. By giving a specific form to the distributions of time-varying attributes, we can calculate the similarity between given data and identify objects by using agglomerative clustering on the basis of the similarity. Experiments in which we compared identification accuracies between our proposed method and a method that regards all attribute values as constant showed that the proposed method improves the precision and recall of object identification.
Perceptual image retrieval using eye movements
Authors: Oyewole Oyekoya, Fred Stentiford
Venue: International Journal of Computer Mathematics (2007)

This paper explores the feasibility of using an eye tracker as an image retrieval interface. A database of 1000 Corel images is used in the study and results are analysed using ANOVA. Results from participants performing image search tasks show that eye tracking data can be used to reach target images in fewer steps than by random selection. The effects of the intrinsic difficulty of finding images and the time allowed for successive selections were also considered. The results indicated evidence of the use of pre-attentive vision during visual search.
Highly Scalable Genotype Phasing by Entropy Minimization
Authors: Alexander Gusev, Ion I. Măndoiu, Bogdan Paşaniuc
Venue: IEEE/ACM Transactions on Computational Biology and Bioinformatics (TCBB) (2008)

A Single Nucleotide Polymorphism (SNP) is a positionin the genome at which two or more of the possible fournucleotides occur in a large percentage of the population. SNPsaccount for most of the genetic variability between individuals,and mapping SNPs in the human population has become thenext high-priority in genomics after the completion of the HumanGenome project. In diploid organisms such as humans, thereare two non-identical copies of each autosomal chromosome. Adescription of the SNPs in a chromosome is called a haplotype.At present, it is prohibitively expensive to directly determine thehaplotypes of an individual, but it is possible to obtain rather easilythe conflated SNP information in the so called genotype. Computationalmethods for genotype phasing, i.e., inferring haplotypesfrom genotype data, have received much attention in recent yearsas haplotype information leads to increased statistical power ofdisease association tests. However, many of the existing algorithmshave impractical running time for phasing large genotype datasetssuch as those generated by the international HapMap project.In this paper we propose a highly scalable algorithm based onentropy minimization. Our algorithm is capable of phasing bothunrelated and related genotypes coming from complex pedigrees.Experimental results on both real and simulated datasets showthat our algorithm achieves a phasing accuracy worse but closeto that of best existing methods while being several orders ofmagnitude faster. The open source code implementation of thealgorithm and a web interface are publicly available at http://dna.engr.uconn.edu/~software/ent/.
Accelerating Molecular Dynamics Simulations with Reconfigurable Computers
Authors: Ronald Scrofano, Maya B. Gokhale, Frans Trouw, Viktor K. Prasanna
Venue: IEEE Transactions on Parallel and Distributed Systems (2008)

With advances in reconfigurable hardware, especially field-programmable gate arrays (FPGAs), it has become possible to use reconfigurable hardware to accelerate complex applications, such as those in scientific computing. There has been a resulting development of reconfigurable computers--computers which have both general purpose processors and reconfigurable hardware, as well as memory and high-performance interconnection networks. In this paper, we describe the acceleration of molecular dynamics simulation with reconfigurable computers. We evaluate several design alternatives for the reconfigurable computer implementation. We show that a single node accelerated with reconfigurable hardware--utilizing fine-grained parallelism in the reconfigurable hardware design--is able to achieve a speed-up of about 2X over the corresponding software-only simulation. We then parallelize the application and study the effect of acceleration on performance and scalability. Specifically, we study strong scaling in which the problem size is fixed. We find that the unaccelerated version actually scales better because it spends more time in computation than the accelerated version does. However, we also find that a cluster of P accelerated nodes gives better performance than a cluster of 2P unaccelerated nodes.
Health IT: A Roundtable Discussion with Healthcare Information Technology Executives
Authors: Thomas Jepsen, Marsha Jepsen
Venue: IT Professional (2008)

Introducing new technology in a healthcare setting is a complex undertaking. In an environment in which accuracy, security, and reliability are critical elements, careful planning is the primary factor in ensuring a successful implementation.
Execution and simulation of (profiled) UML models using pópulo
Authors: Lidia Fuentes, Jorge Manrique, Pablo Sánchez
Venue: Proceedings of the 2008 international workshop on Models in software engineering (2008)

A key factor for the successful adoption of Model-Driven Development (MDD) techniques is the ability to verify models, which can be achieved by model simulation and testing. This is already a reality for UML models, due mainly to the UML action language. However, this action language is purely object-oriented, which implies it needs to be extended to model applications of new software development paradigms, such as aspect-oriented applications. These extensions also require modifying the tools that execute the UML models, which, with the currently available tools, is often not possible. Furthermore, at the current time, there are no tools fully compliant with the UML action language. In order to overcome this limitation, this paper presents Pópulo, an extensible UML model debugger, which interprets the UML action language, compliant with the standard, and that can be customised for executing profiled (i.e. extended) UML models.
A "true" electrical cell model for timing, noise, and power grid verification
Authors: Noel Menezes, Chandramouli Kashyap, Chirayu Amin
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

Empirically characterized equation- and table-based cell models have been applied in static timing analysis for decades. These models have been extended to handle a variety of environmental and circuit phenomena over the years. This has given rise to a profusion of cell models that are used to verify circuit functionality and performance. The recent invention of a second-generation of current source models shows the promise of a unified electrical cell model that comprehensively addresses most of the effects that are perceived as accuracy limiters. In this paper, we describe these accuracy limiters and present comprehensive results for a particular current source model [11].
Multi-year circumpolar assessment of the area burnt in boreal ecosystems using SPOT-VEGETATION
Authors: S. A. Bartalev, V. A. Egorov, E. A. Loupian, I. A. Uvarov
Venue: International Journal of Remote Sensing (2007)

The Russian Academy of Sciences' Space Research Institute has developed a new burnt area mapping method and a five-year database to estimate biomass burning in the Earth's entire boreal region. The mapping method involved SPOT-VEGETATION time-series data analysis to detect inter-annual vegetation changes combined with MODIS hot-spot data to distinguish fire-related changes from other types of disturbances. The burnt area database actually covers the boreal biome for the period 2000-2004 with 1 km spatial resolution and 10-day time frequency, while an automatic data processing chain allows this database to be updated continuously. The accuracy assessment involved comparison with Landsat-ETM+ derived burnt area estimates for Northern Eurasia and ground data for Canada. This Letter describes the satellite sensor data processing method and the results of the accuracy assessment of the burnt area database and provides burnt area statistics for the boreal region countries.
Tutoring model for promoting teaching skills of computer science prospective teachers
Authors: Noa Ragonis, Orit Hazzan
Venue: ACM SIGCSE Bulletin (2008)

One of the greatest challenges Computer Science (CS) teachers face is that of guiding their pupils through problem-solving processes, i.e., the process of constructing a solution for a given problem as an algorithm or a computer program. This paper suggests a tutoring model, to be implemented by prospective CS teachers, that aims at training them to accomplish this challenge. The model is based on one-on-one tutoring sessions, in which the prospective teacher meets a novice undergraduate student taking an introductory CS course and guides him or her through problem-solving processes. The tutoring activity provides the prospective CS teachers with an opportunity to experience teaching situations, especially learners' difficulties with respect to problem-solving processes, and consequently, to improve their teaching skills. The tutoring model was integrated into the Methods of Teaching Computer Science course and was accompanied by a qualitative research. The main research findings indicate that the prospective CS teachers: (a) change their perspective with respect to teaching processes; (b) focus in their teaching on learners' difficulties; (c) increase their awareness to problem-solving processes and to the need to adapt different teaching approaches for different learners; (d) become reflective practitioners; and (e) increase their confidence with respect to teaching processes.
ICT Inclusion and Gender: Tensions in Narratives of Network Engineer Training
Authors: Hazel Gillard, Nathalie Mitev, Susan Scott
Venue: The Information Society (2006)

Government, major information and communications technology (ICT) companies, and educational institutions in the United Kingdom currently claim that ICT skills training offers inclusion into the new economy. We focus on a private-public training initiative and its impact on the socially excluded, specifically lone women parents. Narrative data from four United Kingdom educational sites participating in this computer network engineer training program highlight a systemic paradox: that ICT skills development initiatives designed to support lone women parents are simultaneously working in opposition to broader policy goals such as work-life balance and ironically serve to reproduce the participants' classification as socially excluded. The assumptions underpinning the model of social inclusion driving the ICT skills training course are analyzed critically using the concepts of community of practice, classificatory systems, and marginalization. Our findings suggest that ICT training courses and initiatives should be accompanied by changes in pedagogic practice that accommodate the more wide-ranging needs of those targeted for inclusion, as well as changes in employment settings. We conclude by exploring the implications of this for government policy formation, business vendor qualifications, the design of ICT skills training initiatives, and our understanding of the role of ICT skills in overcoming the digital divide.
Towards Secure E-Commerce Based on Virtualization and Attestation Techniques
Authors: Frederic Stumpf, Claudia Eckert, Shane Balfe
Venue: Proceedings of the 2008 Third International Conference on Availability, Reliability and Security (2008)

We present a secure e-commerce architecture that is resistant to client compromise and man-in-the-middle attacks on SSL. To this end, we propose several security protocols that use attestation techniques offered by the Trusted Computing Group (TCG). Using these protocols, we can ensure that the client configuration remains untampered and trusted for the duration of the transaction. In addition, confidential data, such as authentication passwords, are only accessible by the electronic commerce server to which the users intend to transfer their data. Since we employ a trusted third party that is responsible for verifying a client's platform configuration, our approach does not depend on trusted computing at the server but instead only requires minor modification to server logic.
Parallel repetition in projection games and a concentration bound
Authors: Anup Rao
Venue: Proceedings of the 40th annual ACM symposium on Theory of computing (2008)

In a two player game, a referee asks two cooperating players (who are not allowed to communicate) questions sampled from some distribution and decides whether they win or not based on some predicate of the questions and their answers. The parallel repetition of the game is the game in which the referee samples n independent pairs of questions and sends corresponding questions to the players simultaneously. The players may now answer each question in a way that depends on the other questions they are asked. If the players cannot win the original game with probability better than (1-ε), what's the best they can do in the repeated game? We improve earlier results of Raz and Holenstein, which showed that the players cannot win all copies in the repeated game with probability better than (1-ε3)Ω(n/c) (here c is the length of the answers in the game), in the following ways: We prove the bound (1-ε2)Ω(n) as long as the game is a "projection game", the type of game most commonly used in hardness of approximation results. Our bound is independent of the answer length and has a better dependence on ε. By the recent work of Raz, this bound is essentially tight. A consequence of this bound is to the Unique Games Conjecture of Khot. Many tight or almost tight hardness of approximation results have been proved using the Unique Games Conjecture, so it would be very interesting to prove this conjecture. We make progress towards this goal by showing that it suffices to prove the following easier statement: {Unique Games Conjecture} For every δ,ε> 0, there exists an alphabet size M(ε) such that it is NP-hard to distinguish a Unique Game with alphabet size M for which a 1-ε2 fraction of the constraints can be satisfied from one in which a 1-ε1-δ fraction of the constraints can be satisfied. We also prove a concentration bound for parallel repetition (of general games) showing that for any constant 04 n/c)). An application of this is in testing Bell Inequalities. Our result implies that the parallel repetition of the CHSH game can be used to get an experiment that has a very large classical versus quantum gap.
Composable Information Gradients in Wireless Sensor Networks
Authors: Huijia Lin, Maohua Lu, Nikola Milosavljevic, Jie Gao, Leonidas J. Guibas
Venue: Proceedings of the 7th international conference on Information processing in sensor networks (2008)

In sensor networks we aim to achieve global objectives through local decisions at each node, based only on data available in the node's neighborhood. In this paper, we diffuse information away from source nodes holding desired data, so as to establish information potentials that allow network queries to navigate towards and reach these sources through local greedy decisions, following information gradients. We compute these information potentials by solving for a discrete approximation to a partial differential equation over appropriate network neighborhoods, through a simple local iteration that can be executed in a distributed manner and can be re-invoked to repair the information field locally when links fail, sources move, etc. The solutions to this equation are classical harmonic functions, which have a rich algebraic structure and many useful properties, including the absence of local extrema, providing a guarantee that our local greedy navigation will not get stuck.Unlike shortest path trees, which can also be used to guide queries to sources, information potentials are robust to low-level link volatility as they reflect more global properties of the underlying connectivity. By exploiting the algebraic structure of harmonic functions such potentials can be combined in interesting ways to enable far greater path diversity and thus provide better load balancing than is possible with fixed tree structures, or they can be used to answer range queries about the number of sources in a certain regions by simply traversing the boundary of the region. Potentials for multiple information types can be aggregated and compressed using a variant of the q-digest data structure. The paper provides both analytic results and detailed simulations supporting these claims.
Stereoscopic architecture of 3-D ready DLP-based HDTVs
Authors: Keith Elliott, David Hutchison
Venue: Proceedings of the 2008 workshop on Immersive projection technologies/Emerging display technologiges (2008)

DLP&reg; Technology has existed for over twenty years with a wide range of products currently in production. The legacy of DLP technology includes innovations such as single-chip color displays and SmoothPicture&trade; technology. Recent technological advances have enabled entirely new applications in the area of 3-D stereoscopic viewing. This paper will explain the basic DLP technology and how it has been utilized in today's 3-D HDTV's.