ppxscal/embedding_network huggingface dataset:
Conversations of virtual learning communities: discourse and survey analyses of moderated online synchronous discussions
Authors: Hwee Ling Lim
Venue: International Journal of Web Based Communities (2008)

In web-based education, virtual learning communities are formed to support interaction and attain explicit educational outcomes, with Computer-Mediated Communication (CMC) technologies facilitating most of the interaction. From the sociocultural constructivist view that knowledge building occurs during dialogic interaction, little is known about the impact of online synchronous (chat) interaction on supporting knowledge construction, while online asynchronous interaction has been more widely researched. Moreover, analytical frameworks for educational Computer-Mediated Discourse (CMD), mainly designed for asynchronous discussions, are typically less sensitive to chat exchanges. This paper examines the impact of chat interaction on supporting the knowledge construction processes in two tutorial groups. The discourse analysis results revealed participant involvement in meaning negotiation that builds new knowledge. The survey results showed the availability of scaffolding and the appropriation of shared understandings that are characteristic of knowledge construction processes. These findings can guide the pedagogical design of online synchronous instructional environments that facilitate learning through the conversations of virtual learning communities.
Disjoint directed quadrilaterals in a directed graph
Authors: Danhong Zhang, Hong Wang
Venue: Journal of Graph Theory (2005)

Let D be a directed graph of order 4k, where k is a positive integer. Suppose that the minimum degree of D is at least 6k&thinsp;-&thinsp;2. We show that D contains k disjoint directed quadrilaterals with only one exception. &copy; 2005 Wiley Periodicals, Inc. J Graph Theory
Scalable visualization of model differences
Authors: Sven Wenzel
Venue: Proceedings of the 2008 international workshop on Comparison and versioning of software models (2008)

If large models are compared their difference can contain a huge number of local changes. Conventional methods for displaying differences cannot reasonably handle such large differences. This paper proposes a solution to this problem. Our approach is based on the concept of polymetric views and extends it in two ways: firstly, we propose metrics for differences which quantify properties of differences and distinguish relevant from irrelevant changes. Moreover, we propose new graphical features of polymetric views. This combination provides a scalable presentation of differences which makes the changes of large models comprehensible.
Server-based data push architecture for multi-processor environments
Authors: Xian-He Sun, Surendra Byna, Yong Chen
Venue: Journal of Computer Science and Technology (2007)

Data access delay is a major bottleneck in utilizing current high-end computing (HEC) machines. Prefetching, where data is fetched before CPU demands for it, has been considered as an effective solution to masking data access delay. However, current client-initiated prefetching strategies, where a computing processor initiates prefetching instructions, have many limitations. They do not work well for applications with complex, non-contiguous data access patterns. While technology advances continue to increase the gap between computing and data access performance, trading computing power for reducing data access delay has become a natural choice. In this paper, we present a server-based data-push approach and discuss its associated implementation mechanisms. In the server-push architecture, a dedicated server called Data Push Server (DPS) initiates and proactively pushes data closer to the client in time. Issues, such as what data to fetch, when to fetch, and how to push are studied. The SimpleScalar simulator is modified with a dedicated prefetching engine that pushes data for another processor to test DPS based prefetching. Simulation results show that L1 Cache miss rate can be reduced by up to 97% (71% on average) over a superscalar processor for SPEC CPU2000 benchmarks that have high cache miss rates.
Scalable Distribution of XML Content with XNet
Authors: Raphael Chand, Pascal Felber
Venue: IEEE Transactions on Parallel and Distributed Systems (2008)

The XNet XML content network was designed to implement efficient and reliable distribution of structured XML content to very large populations of consumers. For that purpose, our system integrates several technologies: the routing protocol, XRoute, makes extensive use of subscription aggregation to limit the size of routing tables while ensuring perfect routing (i.e., an event is forwarded to a link only if it leads to an interested consumer). The filtering engine, XTrie, uses a sophisticated algorithm to match incoming XML documents against large populations of tree-structured subscriptions, while the XSearch subscription management algorithm enables the system to efficiently manage large and highly dynamic consumer populations. Finally, our XNet system integrates reliability mechanisms to guarantee that its state is consistent with the consumer population and implements several approaches to fault-tolerance to recover from various types of router and link failures. We have analyzed the efficiency of our techniques with various simulations and, to assess the performance of our system in realistic settings and to show that it is perfectly suitable for large-scale distributed environments, we have performed a large scale experimental deployment on the PlanetLab testbed.
The influence of computer-assisted instruction on students' conceptual understanding of chemical bonding and attitude toward chemistry: A case for Turkey
Authors: Haluk Özmen
Venue: Computers Education (2008)

In this study, the effect of computer-assisted instruction on conceptual understanding of chemical bonding and attitude toward chemistry was investigated. The study employed a quasi-experimental design involving 11 grade students; 25 in an experimental and 25 in a control group. The Chemical Bonding Achievement Test (CBAT) consisting of 15 two-tier questions and the Chemistry Attitude Scale (CAS) consisting of 25 item were the principal data collection tools used. The CBAT and CAS instruments were administered in the form of a pre-test and post-test. Analyses of scores of the two groups in the post-test were compared and a statistically significant difference was found between groups in favor of experimental group. It also seems students from the experimental group were more successful than the control group students in remediation of alternative conceptions. The results of this study suggest that teaching-learning of topics in chemistry related to chemical bonding can be improved by the use of computer-assisted teaching materials.
How humans evaluate the impression when interacting haptically with a robot
Authors: Yoshiyuki Miyamoto, Takashi Maeno
Venue: Proceedings of the 1st international conference on Robot communication and coordination (2007)

It is necessary to analyze evaluation structure of impression of human for robot's natural interaction with human. In this paper, we assume hierarchy in evaluation structure of impression of human, and clarify the relationship between lower impression and higher impression in human-robot haptic interaction. Lower and higher stand for a strong and weak relationship to physical property of robot's motion. We divide robot's motions in haptic interaction into 16 basic motions. Through sensory evaluation and factor analysis, four lower impression factors and two higher impression factors are extracted. From the results of multiple regression analysis, we formulate the relationship between lower impression and higher impression.
A Fast Approach to Tomographic Reconstruction from a Single Radiograph
Authors: Chao Huang
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 01 (2008)

A new CT reconstruction method, that is the second-order difference transformation (SODT) algorithmis introduced. It can reconstruct CT image without artifacts and determine the kinds of the materials simultaneously from a single radiograph. Otherwise, it is much faster than other reconstruction approaches, like filtered back-projection method (FBP) and algebraic reconstruction technique (ART). Although it requires strong prior knowledge, there is no requiring of the symmetry of the object to utilize this approach. So the SODT method is very suitable for X-ray or industrial CT inspection, where many objects have nearly circular symmetry, especially for inspecting material, structure, thickness and defect etc.
Two-Way Coupled SPH and Particle Level Set Fluid Simulation
Authors: Frank Losasso, Jerry Talton, Nipun Kwatra, Ronald Fedkiw
Venue: IEEE Transactions on Visualization and Computer Graphics (2008)

Grid-based methods have difficulty resolving features on or below the scale of the underlying grid. Although adaptive methods (e.g. RLE, octrees) can alleviate this to some degree, separate techniques are still required for simulating small-scale phenomena such as spray and foam, especially since these more diffuse materials typically behave quite differently than their denser counterparts. In this paper, we propose a two-way coupled simulation framework that uses the particle level set method to efficiently model dense liquid volumes and a smoothed particle hydrodynamics (SPH) method to simulate diffuse regions such as sprays. Our novel SPH method allows us to simulate both dense and diffuse water volumes, fully incorporates the particles that are automatically generated by the particle level set method in under-resolved regions, and allows for two way mixing between dense SPH volumes and grid-based liquid representations.
Calibrating and mosaicking surface velocity measurements from interferometric SAR data with a simultaneous least-squares adjustment approach
Authors: H. Liu, J. Yu, Z. Zhao, K. C. Jezek
Venue: International Journal of Remote Sensing (2007)

The repeat-pass interferometric SAR (InSAR) technique has been well established as a precise means to extract two-dimensional surface velocity fields. Many applications require velocity measurements over a large area and multiple InSAR image frames from the same and/or adjacent orbits are needed to achieve full ground coverage. The conventional frame-by-frame processing approach often causes velocity discrepancies and discontinuities between adjacent frames. In addition, absolute velocity information may not be derived for some image frames due to a lack of velocity control points. We present a unified simultaneous least-squares adjustment method for calibrating and merging surface displacements derived from multiple InSAR image frames using the speckle tracking method. Observation equations have been mathematically derived for velocity control points and tie points. The major advantages of our method include consistent and smooth transition of velocity measurements between adjacent frames and dramatic reduction of velocity control point requirements. For those frames devoid of velocity control points, absolute velocity measurements can still be derived with this method based on distant velocity control points in other frames. The benefits of our method are demonstrated and evaluated by using Radarsat InSAR data for Antarctica acquired in 1997.
Using a High-Fidelity Simulation Framework for Performance Singularity
Authors: Chris Scrapper, Raj Madhavan, Stephen Balakirsky
Venue: Proceedings of the 36th Applied Imagery Pattern Recognition Workshop (2007)

A common way to evaluate the performance of a system is to compare the algorithmic outputs with ground truth to identify divergences in the system's performance and discover the errors it is prone to. In the absence of such ground truth or as a follow-on to performance evaluation, performance analysis at the algorithmic level can provide developers insight into performance singularities. Such performance singularity identification and testing provides real-time meta-data that allows developers to understand the impact of singularities on the overall performance of the system. As an example of the concepts developed in this paper, we present a navigation solution based on image registration algorithms and the methodology used for the identification and testing of performance singularities of this algorithm.
Full Open Defects in Nanometric CMOS
Authors: Daniel Arumí, Rosa Rodríguez-Montañés, Joan Figueras, Stefan Eichenberger, Camelia Hora, Bram Kruseman
Venue: Proceedings of the 26th IEEE VLSI Test Symposium (2008)

Full open defects on the interconnect lines cause the broken wires to become floating. The voltage of a floating line depends on its topological characteristics, namely: parasitic capacitances to neighbouring structures, transistor capacitances of the downstream gate(s) and the trapped charge. However, in nanometric CMOS technologies, the oxide thickness is reduced below a few tens of Å causing the gate tunnelling leakage to strongly impact the behaviour of defective circuits with full open defects. Floating lines can not be considered electrically isolated anymore and are subjected to transient evolutions until arriving at a quiescent state, determined by the technology and the downstream gate(s). The occurrence of full opens as well as the impact of the gate tunnelling leakage is expected to increase for future technologies. The analysis of full opens affecting basic CMOS gates is presented and their defective behaviour characterized. The prediction of the defective logic response of such basic gates is presented for nanometric technologies based on Predictive Technology Models. The final steady state is found to be independent on the initial state of the floating node. Experimental evidence of this behaviour is presented for an industrial chip of 0.18µm technology.
Research and Exploit on PCR Apparatus
Authors: Weihua Zhao, Min Zhang, Yan Li, Chong Tang
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 02 (2008)

The principle and condition of the polymerase chain reaction (PCR) has been analyzed, and instrument system of gene amplification which takes M30627FJPGP as the core was excogitated. The design proposal of the hardware was provided, the factors which influence the calefaction and refrigeration effect of PCR appearance as well asthe special requirements to electromagnetic compatibility were analyzed, and the controls algorithms of fuzzy self-adjustment PID that to bedefinite to systematic characteristic was proposed. Experiment shows that, the temperature-controlledprecision of the systematic can be achieved to ±0.1degrees Centigrade, the velocity of temperatureheating up and cooling is fast, the repetitiveness isfine, and instrument prototype of a machine has been used in temperature controlling of gene increasing already. The design method of the systematic software and hardware also has certain interrelated significances to other similar high-accuracy temperature control occasions.
Technical Section: MSRS: A fast linear solver for the real-time simulation of deformable objects
Authors: Marcos García, Oscar D. Robles, Luis Pastor, Angel Rodríguez
Venue: Computers and Graphics (2008)

Nowadays many interactive computer graphics applications deal with soft-bodies. These applications are always demanding higher and higher levels of realism, increasing the complexity of the animated scenarios. Therefore, the techniques used to animate the objects should be very efficient to grant interactivity. Most often, an accurate answer is not needed and a visually plausible one is enough. One of the most important issues in physically based simulations is to keep the model stable under all simulation conditions. In this paper we present a technique called matrix system reduction solver (MSRS) to highly accelerate the real-time simulation of a finite element-based technique. Our method is fast, visually plausible and robust. In the first stage of the algorithm an initial solution is estimated. Then, only those equations showing a large error are solved using a more precise technique. In the final stage the linear and angular momenta are corrected. Experimental results show the feasibility of this new approach from the point of view of performance compared to the results provided by the stiffness warping method.
Area, delay, and power characteristics of standard-cell implementations of the AES S-Box
Authors: Stefan Tillich, Martin Feldhofer, Thomas Popp, Johann Großschädl
Venue: Journal of Signal Processing Systems (2008)

Cryptographic substitution boxes (S-boxes) are an integral part of modern block ciphers like the Advanced Encryption Standard (AES). There exists a rich literature devoted to the efficient implementation of cryptographic S-boxes, wherein hardware designs for FPGAs and standard cells received particular attention, in this paper we present a comprehensive study of different standard-cell implementations of the AES S-box with respect to timing (i.e. critical path), silicon area, power consumption, and combinations of these cost metrics. We examine implementations which exploit the mathematical properties of the AES S-box, construcions based on hardware look-up tables, and dedicated low-power solutions. Our results show that the timing, area, and power properties of the different S-box realizations can vary by up to almost an order of magnitude. In terms of area and area-delay product, the best choice are implementations which calculate the S-box output. On the other hand, the hardware look-up solutions are characterized by the shortest critical path. The dedicated low-power implementations do not only reduce power consumption by a large degree, but they also show good timing properties and offer the best power-delay and power-area product, respectively.
Video 2.0: Building Next-Generation Video Networks
Authors: Paul Sanchirico
Venue: Computer (2008)

IP networks offer cost-effective and scalable approaches to TV/video delivery.
Assessing different methods of generating a three-dimensional numerical model mesh for a complex stream bed topography
Authors: Pascale M. Biron, Timothy W. Haltigin, Richard J. Hardy, Michel F. Lapointe
Venue: International Journal of Computational Fluid Dynamics (2007)

Three-dimensional numerical models of flow over complex bed geometry are becoming widely used in river and coastal engineering. Boundary-fitted coordinate grids are typically used to deal with this problem in natural channels. Recently, a regular structured grid method based on numerical porosity has been developed for high-resolution gravel-bed models. A simpler alternative approach is to use a Cartesian mesh with an interpolated 3D solid object representing the river bed. The objective of this study is to assess the impact of these three methods of mesh generation on the simulated flow field above complex bed topography around stream deflectors in a laboratory setting. Results show marked differences between the three types of simulations when running mesh sensitivity analysis. Because the bed porosity approach uses the digital elevation model (DEM) information in each cell to represent bed topography, it requires a finer mesh resolution in order to reach an accurate solution. Although there was good qualitative agreement between the simulated flow fields and Acoustic Doppler Velocity measurements, the quantitative comparison showed relatively poor agreement for all mesh design types. However, the three mesh types were in good agreement when compared to each other for velocity and pressure variables (average correlation coefficient, r, of 0.95), with the 3D object bed and bed porosity showing the best agreement (r = 0.97). Simulated turbulence variables (KE and EP), however, showed more scatter (r = 0.85) and slopes markedly different from unity.
Local Hoare reasoning about DOM
Authors: Philippa A. Gardner, Gareth D. Smith, Mark J. Wheelhouse, Uri D. Zarfaty
Venue: Proceedings of the twenty-seventh ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems (2008)

The W3C Document Object Model (DOM) specifies an XML update library. DOM is written in English, and is therefore not compositional and not complete. We provide a first step towards a compositional specification of DOM. Unlike DOM, we are able to work with a minimal set of commands and obtain a complete reasoning for straight-line code. Our work transfers O'Hearn, Reynolds and Yang's local Hoare reasoning for analysing heaps to XML, viewing XML as an in-place memory store as does DOM. In particular, we apply recent work by Calcagno, Gardner and Zarfaty on local Hoare reasoning about simple tree update to this real-world DOM application. Our reasoning not only formally specifies a significant subset of DOM Core Level 1, but can also be used to verify, for example, invariant properties of simple Javascript programs.
ACM TOSEM: FAQs and figures
Authors: David Notkin
Venue: ACM SIGSOFT Software Engineering Notes (2008)

It's been a while since I've written a column on TOSEM. One reason for this is, of course, that I simply haven't gotten to it. The other reason for this is because of you: I've had few, if any, questions or comments about TOSEM from the SEN readership. If this was because everything at TOSEM was perfect and we were so transparent that you knew everything we knew, I'd be thrilled. But that's just never the case. So, please send me email with your comments, questions, concerns, TOSEM-related jokes, or whatever.
Quantitative Prediction of MHC-II Peptide Binding Affinity Using Global Description of Peptide Sequences
Authors: Wen Zhang, Juan Liu, Yanqing Niu, Lian Wang, Zhi Zhang
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 01 (2008)

The prediction of MHC-II binding peptides has long been a principal challenge in immunology. Recently, the modeling of MHC-II binding peptides has come to emphasize quantitative prediction, instead of categorizing peptides as no-binder or high-binderand moderate-binder. In this paper, we develop a support vector machine regression’s (SVR) approach to predict MHC-II binding peptides. Considering global description of the peptide sequences, input vectors of same lengths are generated from peptides of different lengths, and then support vector machine regression is used to model binding affinities between MHC-II molecules and peptides; at last we obtain the prediction model called SVRMHC-II. When applied to three MHC-II alleles, SVRMHC-II produces better predictions than several prominent methods in terms of area under ROC curve, indicating it is an effective tool.