ppxscal/embedding_network huggingface dataset:
Constructions of dynamic geometry: A study of the interpretative flexibility of educational software in classroom practice
Authors: Kenneth Ruthven, Sara Hennessy, Rosemary Deaney
Venue: Computers Education (2008)

The idea of 'interpretative flexibility' underpins new approaches to studying technological artefacts and curricular resources in use. This paper opens by reviewing - in this light - the evolving design of dynamic geometry, its pioneering use within classroom projects, and early sketches of its mainstream use in ordinary classrooms. After examining curricular context and its instrumental dimension, the paper then reports a study of teacher constructions of dynamic geometry in classroom practice, conducted in professionally well-regarded mathematics departments in English secondary schools. From departmental focus-group interviews, four teacher-nominated examples of successful practice were selected for study in depth through lesson observation and post-lesson interview. Iterative thematic analysis was employed, first to establish a narrative outline of each case, and then the ideas and issues salient across cases. The study illustrates the interpretative flexibility surrounding the emergent use of dynamic geometry. It found important differences in practical elaboration of the widespread idea of employing dynamic geometry to support guided discovery. The process of evaluating the costs and benefits of student software use was influenced by the extent to which such use was seen as providing experience of a mathematical reference model, and more fundamentally as promoting mathematically disciplined interaction. Approaches to handling apparent mathematical anomalies of software operation depended on whether these were seen as providing opportunities to develop students' mathematical understanding, in line with a more fundamental pedagogical orientation towards supporting learning through analysis of mathematical discrepancies. Such variation was associated with differences in positioning dynamic geometry in relation to curricular norms and in privileging a mathematical register for framing figural properties. Across all cases, however, incorporating dynamic manipulation into mathematical discourse moved implicitly beyond established norms when dragging was used to focus attention on continuous dynamic variation, rather than being treated as an efficient means of generating multiple static figures.
Unlocking Human Potential through Technical Innovation
Authors: Elizabeth Mynatt
Venue: IEEE Computer Graphics and Applications (2008)

Alongside the formation of the College of Computing at Georgia Tech 15 years ago, the GVU Center for research was created to study, predict, and design future innovations in computing based on then unseen uses of computing technologies by enterprises not associated with computer science. GVU's research agenda has evolved rapidly as people's capacity and desire for innovation has been almost without limits. In this article, the author reflects on the evolving mission of this interdisciplinary research center, describing GVU's agenda going forward and how this agenda mirrors changes in the computing industry.
The computational complexity of graph contractions II: Two tough polynomially solvable cases
Authors: Asaf Levin, Daniel Paulusma, Gerhard J. Woeginger
Venue: Networks (2008)

For a fixed pattern graph H, let H-CONTRACTIBILITY denote the problem of deciding whether a given input graph is contractible to H. This article is part II of our study on the computational complexity of the H-CONTRACTIBILITY problem. In the first article we pinpointed the complexity for all pattern graphs with five vertices except for two pattern graphs H. Here, we present polynomial time algorithms for these two remaining pattern graphs. Interestingly, in all connected cases that are known to be polynomially solvable, the pattern graph H has a dominating vertex, whereas in all cases that are known to be NP-complete, the pattern graph H does not have a dominating vertex. &copy; 2008 Wiley Periodicals, Inc. NETWORKS, 2008
Web technologies and programming languages used in production systems management
Authors: Cioca Lucian-Ionel, Cioca Marius
Venue: Proceedings of the 5th WSEAS International Conference on Circuits, Systems, Electronics, Control & Signal Processing (2006)

The development of the Internet has led to new approaches to production systems management, which replaced the classic "four-wall" organisation to concepts that preceded that of Computer Integrated Manufacturing (CIM) such as: the virtual, extended, fractal etc. enterprise. Processes may occur disparately, anywhere in the world, on the entire life cycle of a particular product, beginning with its initial stage, that of demand and continuing with that of conception, design, manufacturing, sale, decommissioning, etc. All of these are possible by a correct and concrete use of information technology in an Intra(Inter)net.
Analysis of the ZVS two-switch forward converter with synchronous current doubler rectifier
Authors: Bor-Ren Lin, Jin-Fa Wan
Venue: International Journal of Circuit Theory and Applications (2008)

A soft switching two-switch forward converter is presented to achieve zero voltage switching (ZVS) turn-on of switching devices. In the adopted converter, a buck-boost type of active clamp is connected in parallel with the primary winding of transformer. The energy stored in the transformer leakage inductance and magnetizing inductance can be recovered so that the peak voltage stress of switching devices is limited. The resonance between the transient interval of two main and auxiliary switches is used to achieve ZVS turn-on of all switches. The current doubler synchronous rectifier is used in the secondary side of transformer for reducing the root mean square value of output inductor current, transformer secondary winding current and output voltage ripple by cancelling the current ripple of two output inductors. First, the circuit configuration and the principles of operation are analyzed in detail. The steady-state analysis and design consideration are also presented. Finally, experimental results with a laboratory prototype based on a 380&thinsp;V input and 12&thinsp;V-30&thinsp;A output were provided to verify the effectiveness of the proposed converter. Copyright &copy; 2007 John Wiley & Sons, Ltd.
A Contemporary Technique to Guarantee Quality of Service (QoS) for Heterogeneous Data Traffic
Authors: Calduwel Newton P.
Venue: Proceedings of the 2008 International Conference on Information Security and Assurance (isa 2008) (2008)

The upcoming high-speed networks are expected to support a wide variety of real-time multimedia applications. However, the current Internet architecture offers mainly best-effort service and does not meet the requirements of future integrated services networks that will require guarantee for transferring heterogeneous data. There are many parameters involve in improving the performance of a computer network such as reliability, delay, jitter, bandwidth, etc. These parameters together determine the Quality of Service (QoS). The requirements of the above parameters will vary from one application to another application. Applications like file transfer, remote login, etc., will require high reliability. But, applications like audio, video, etc., will require low reliability, because they can tolerate errors. The objectives of this paper are to propose a technique to store the results of a data transfer in binary based on the above parameters, to compare the expected requirements with the actual requirements, to show performance degradation and to suggest ideas to minimize differences between expected requirements and actual requirements. Ultimately, the outcome of this paper will give better results to improve the performance of the network.
Algorithms and Data Structures for Multi-Adaptive Time-Stepping
Authors: Johan Jansson, Anders Logg
Venue: ACM Transactions on Mathematical Software (TOMS) (2008)

Multi-adaptive Galerkin methods are extensions of the standard continuous and discontinuous Galerkin methods for the numerical solution of initial value problems for ordinary or partial differential equations. In particular, the multi-adaptive methods allow individual and adaptive time steps to be used for different components or in different regions of space. We present algorithms for efficient multi-adaptive time-stepping, including the recursive construction of time slabs and adaptive time step selection. We also present data structures for efficient storage and interpolation of the multi-adaptive solution. The efficiency of the proposed algorithms and data structures is demonstrated for a series of benchmark problems.
A Novel Network Intrusion Detection System (NIDS) Based on Signatures Search of Data Mining
Authors: Hu Zhengbing, Li Zhitang, Wu Junqi
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

Network security has been a very important issue, since the rising evolution of the Internet. There has been an increasing need for security systems against the external attacks from the hackers. One important type is the Intrusion Detection System (IDS). There are two major categories of the analysis techniques of IDS: the anomaly detection and the misuse detection.Here we forcus on misuse detection, the misuse detection collected the attack signatures in a database as the same as virus protection software to detect the relate attacks. we propose an algorithm to use the known signature to find the signature of the related attack quickly.
e-du box: educational multimedia with tangible-enhanced interaction
Authors: André Wilson Brotto Furtado, Taciana Pontual Falcão, Alex Sandro Gomes, Carlos Eduardo, Monteiro Rodrigues, Roberto Sonnino
Venue: Proceedings of the 7th ACM conference on Designing interactive systems (2008)

Media resources usage has significant impact on children literacy in the first school years in Brazil [5]. Computer software and tangible interfaces can help engage pupils in effective learning activities. Tangible interfaces built with familiar objects of our everyday lives such as wood and tissues are well accepted by pupils. In this work, we detail our design and evaluation of e-du box -- an educational, authoring and sharing multimedia platform including a tangible companion that provides feedback for users. We employed a participatory design process based on providing supports intended to help children engage in different tasks. We could elicit a list of design guidelines for this specific application. We discuss our experience with this design approach and explore its implications.
Are we talking about the same structure?: a unified approach to hypertext links, xml, rdf and zigzag
Authors: Amir Pourabdollah, Helen Ashman, Tim Brailsford
Venue: Proceedings of the nineteenth ACM conference on Hypertext and hypermedia (2008)

There are many different hypertext systems and paradigms, each with their apparent advantages. However the distinctions are perhaps not as significant as they seem. If we can reduce the core linking functionality to some common structure, which allows us to consider hypertext systems within a common model, we could identify what, if anything, distinguishes hypertext systems from each other. This paper offers such a common structure, showing the conceptual similarities between each of these systems and paradigms.
A Data Mining Approach for Coronary Heart Disease Prediction using HRV Features and Carotid Arterial Wall Thickness
Authors: Heon Gyu Lee, Ki Yong Noh, Keun Ho Ryu
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 01 (2008)

The main objective of our work has been to develop and then propose a new and unique methodology useful in developing the various features of heart rate variability (HRV) and carotid arterial wall thickness helpful in diagnosing cardiovascular disease. We also propose a suitable prediction model to enhance the reliability of medical examinations and treatments for cardiovascular disease. We analyzed HRV for three recumbent postures. The interaction effects between the recumbent postures and groups of normal people and heart patients were observed based on HRV indexes. We also measured intimamedia of carotid arteries and used measurements of arterial wall thickness as other features. Patients underwent carotid artery scanning using high-resolution ultrasound devised in a previous study. In order to extract various features, we tested six classification methods. As a result, CPAR and SVM (gave about 85%-90% goodness of fit) outperforming the other classifiers.
Problems and opportunities for model-centric versus code-centric software development: a survey of software professionals
Authors: Andrew Forward, Timothy C. Lethbridge
Venue: Proceedings of the 2008 international workshop on Models in software engineering (2008)

We present some results of a survey of 113 software practitioners conducted between April and December 2007. The aim of the survey was to uncover their attitudes and experiences regarding software modeling, and development approaches that avoid modeling. We were motivated by observations that modeling is not widely adopted; many developers continue to take a code-centric approach. Key findings overall include: Modeling tools are primarily used to create documentation and for up-front design with little code generation; and participants believe that model-centric approaches to software engineering are easier but are currently not very popular as most participants currently work in code-centric environments. Key findings from sub-samples include: problems identified with model-centric approaches are similar regardless of a participant's country. Programmers that model extensively (versus those that do not model much) are more likely to agree that models become out of date and inconsistent with code.
Cryptanalysis and Improvement on a Digital Signature Scheme without using One-way Hash and Message Redundancy
Authors: Jie Liu, Jianhua Li
Venue: Proceedings of the 2008 International Conference on Information Security and Assurance (isa 2008) (2008)

Digital signature schemes based on public-key cryptosystems generally permit existential forgery, except the schemes are equipped with some message formatting mechanisms, such as using hash functions or padding redundancies. In 2004, Chang et al. proposed a new digital signature scheme, and claimed the scheme without using any hash function or padding any redundancy can resist forgery attacks. However, many attacks on Chang et al.’s scheme were presented. Kang et al. also gave an effective improvement to resist these forgery attacks. In this letter, we gave a further improvement to shorten the signed signature. Our improvement keeps the security of Kang et al.’s scheme and makes it more efficient in computation and communication.
2008 Special Issue: Robotics and neuroscience: A rhythmic interaction
Authors: Renaud Ronsse, Philippe Lefèvre, Rodolphe Sepulchre
Venue: Neural Networks (2008)

At the crossing between motor control neuroscience and robotics system theory, the paper presents a rhythmic experiment that is amenable both to handy laboratory implementation and simple mathematical modeling. The experiment is based on an impact juggling task, requiring the coordination of two upper-limb effectors and some phase-locking with the trajectories of one or several juggled objects. We describe the experiment, its implementation and the mathematical model used for the analysis. Our underlying research focuses on the role of sensory feedback in rhythmic tasks. In a robotic implementation of our experiment, we study the minimum feedback that is required to achieve robust control. A limited source of feedback, measuring only the impact times, is shown to give promising results. A second field of investigation concerns the human behavior in the same impact juggling task. We study how a variation of the tempo induces a transition between two distinct control strategies with different sensory feedback requirements. Analogies and differences between the robotic and human behaviors are obviously of high relevance in such a flexible setup.
Discovering properties about arrays in simple programs
Authors: Nicolas Halbwachs, Mathias Péron
Venue: ACM SIGPLAN Notices (2008)

Array bound checking and array dependency analysis (for parallelization) have been widely studied. However, there are much less results about analyzing properties of array contents. In this paper, we propose a way of using abstract interpretation for discovering properties about array contents in some restricted cases: one-dimensional arrays, traversed by simple "for" loops. The basic idea, borrowed from [GRS05], consists in partitioning arrays into symbolic intervals (e.g., [1,i -- 1], [i,i], [i + 1,n]), and in associating with each such interval I and each array A an abstract variable AI; the new idea is to consider relational abstract properties ψ(AI, BI, ...) about these abstract variables, and to interpret such a property pointwise on the interval I: ∀l ∈ I, ψ(A[l], B[l],...). The abstract semantics of our simple programs according to these abstract properties has been defined and implemented in a prototype tool. The method is able, for instance, to discover that the result of an insertion sort is a sorted array, or that, in an array traversal guarded by a "sentinel", the index stays within the bounds.
DS-MOSD: A Dynamic Selectable Master OSD Model for Large-Scale Object-Based Storage System
Authors: Yinliang Yue, Fang Wang, Dan Feng
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

I/O performance for very large-scale storage systems has become more and more important as the need for storage has grown dramatically. Replication is one of the most important approaches to improve the I/O performance of massive distributed storage system. The storage node to which the Read/Write request is directed is the critical issue when multiple replicas exist in some different storage nodes simultaneously. This paper proposes and evaluates a novel master OSD model, called Dynamic Selectable Master OSD (DSMOSD), which allows client to direct the Read/Write request to the optimized OSD. This approach has the salient advantage of simultaneously improving I/O performance and balancing the loads of all the OSDs. This paper first describes the architecture of Master OSD and characterizes the advantages of this model contrasting to the pseudo random hash function. Then an improved model, which is considered as DS-MOSD, is presented and evaluated. The experimental results show that the load unbalance degree and network overheads of DS-MOSD model are smaller than that of Fixed MOSD model, while the success probability of Write/Update transactions of DS-MOSD model is larger than that of Fixed MOSD model.
Benefits of Job Exchange between Autonomous Sites in Decentralized Computational Grids
Authors: Christian Grimme, Joachim Lepping, Alexander Papaspyrou
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

This paper examines the job exchange between parallel compute sites in a decentralized Grid scenario. Here,the local scheduling system remains untouched and continues normal operation. In order to establish the collaboration and interaction between sites in a Grid context,a middleware layer that is responsible for the migration of jobs is supplemented. Independent users are assumed to submit their jobs to their site-local middleware layer, which in turn can request jobs for execution from alien sites. The simulation results are obtained using real workload traces and compared to the performance of the EASY Backfilling algorithm in an equal single-site scenario. It is shown that collaboration between site is beneficial for all high utilized participants as it is possible to achieve shorter response times for jobs compared to the best single-site scheduling results.
Study of classical conditioning in Aplysia through the implementation of computational models of its learning circuit
Authors: A. Santos, A. Porto, J. Romero, A. Albó, A. Pazos
Venue: Journal of Experimental Theoretical Artificial Intelligence (2007)

The learning phenomenon can be analysed at various levels, but in this paper we treat a specific paradigm of artificial intelligence, i.e. artificial neural networks (ANNs), whose main virtue is their capacity to seek unified and mutually satisfactory solutions which are relevant to biological and psychological models. Many of the procedures and methods proposed previously have used biological and/or psychological principles, models, and data; here, we focus on models which look for a greater degree of coherence. Therefore we analyse and compare all aspects of the Gluck-Thompson and Hawkins ANN models. A multithread computer model is developed for analysis of these models in order to study simple learning phenomena in a marine invertebrate (Aplysia californica) and to check their applicability to research in psychology and neurobiology. The predictive capacities of the models differs significantly: the Hawkins model provides a better analysis of the behavioural repertory of Aplysia on both the associative and the non-associative learning level. The scope of the ANN modelling technique is broadened by integration with neurobiological and behavioural models of associative learning, allowing enhancement of some architectures and procedures that are currently being used.
Encryption tools for devices with limited resources
Authors: Raquel Lacuesta Gilaberte, Lourdes Peñalver Herrero
Venue: Proceedings of the 4th WSEAS International Conference on Applied Informatics and Communications (2004)

In current mobile applications platforms, lack of security is one of the main obstacles to developing mobile commerce. Electronic commerce applications demand flexibility, personalization and optimized of security systems [1]. Low weight encryption algorithms must be used to provide applications with an appropriate degree of security. In this article we deal with the programming of secure applications using Java programming language. Since Java does not provide any cryptographic API for programming applications for mobile devices, we analyze cryptographic solutions proposed by third parties. We discuss the Bouncy Castle solution and the best encryption algorithms for low power devices.
Electro-osmotic characteristics of Polystyrene microchips - Experiments and modeling
Authors: Walter Schrott, Michal Přibyl, Jakub Štpánek, Dalimil Šnita
Venue: Microelectronic Engineering (2008)

Electro-osmotic characteristics such as the electro-osmotic velocity, the electro-osmotic mobility and zeta-potential were determined in polystyrene microfluidic chips by the conductivity (electric current monitoring) method. The capillary microchips were fabricated with the use of micromilling and hot assembling techniques. A linear dependence of the electro-osmotic velocity on the voltage applied on 39mm long microcapillaries was obtained. The electro-osmotic mobility and zeta-potential were found to be equal to 2.26+/-0.12x10^-^8 m^2V^-^1s^-^1 and -29.0+/-1.5mV, respectively. The conductivity method is based on the electro-osmotic replacement of two electrolytes with different electric conductivities under a constant voltage. This fact leads to a non-linear distribution of the electric field intensity along the capillary. We developed two dynamical mathematical models describing the conductivity method. It was found that the formation of complex velocity fields and significant gradients of pressure and the electric field intensity accompanies this method. It finally results in a non-linear time response of electric current.