ppxscal/embedding_network huggingface dataset:
Revisiting 2DR-tree insertion
Authors: Marc Moreau, Wendy Osborn
Venue: Proceedings of the 2008 C3S2E conference (2008)

We take another look at the 2DR-tree. In particular, we revisit its node structure, validity rules and the insertion strategy. The 2DR-tree uses 2D nodes so that the relationships between all objects can be maintained. The existing structure has many advantages. However, two limitations include a high tree height and a low space utilization of its nodes. We propose changes to the 2DR-tree structure, validity rules and insertion strategy. Preliminary results show significant improvements in height and space utilization over the existing 2DR-tree.
No-gap second-order optimality conditions for optimal control problems with a single state constraint and control
Authors: J. Fr&#x00e9;d&#x00e9;ric Bonnans, Audrey Hermant
Venue: Mathematical Programming: Series A and B (2008)

The paper deals with optimal control problems with only one control variable and one state constraint, of arbitrary order. We consider the case of finitely many boundary arcs and touch times. We obtain a no-gap theory of second-order conditions, allowing to characterize second-order quadratic growth.
Fast algorithms for constructing t-spanners and paths with stretch t
Authors: E. Cohen
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

The distance between two vertices in a weighted graph is the weight of a minimum-weight path between them. A path has stretch t if its weight is at most t times the distance between its end points. We consider a weighted undirected graph G=(V, E) and present algorithms that compute paths with stretch 2/spl les/t/spl les/log n. We present a O/spl tilde/((m+k)n/sup (2+/spl epsiv///t)) time randomized algorithm that finds paths between k specified pairs of vertices and a O/spl tilde/((m+ns)n/sup 2(1+log(n)/ /sup m+/spl epsiv/)/t/) deterministic algorithm that finds paths from s specified sources to all other vertices (for any fixed /spl epsiv/>0), where n=|V| and m=|E|. This improves significantly over the slower O/spl tilde/(min{k, n}m) exact shortest paths algorithms and a previous O/spl tilde/(mn/sup 64/t/+kn/sup 32/t/) time algorithm by Awerbuch et al. A t-spanner of a graph G is a set of weighted edges on the vertices of G such that distances in the spanner are not smaller and within a factor of t from the corresponding distances in G. Previous work was concerned with bounding the size and efficiently constructing t-spanners. We construct t-spanners of size O/spl tilde/(n/sup 1+(2+/spl epsiv///t)) in O/spl tilde/(mn/sup (2+/spl epsiv///t)) expected time (for any fixed /spl epsiv/>0), what constitutes a faster construction (by a factor of n/sup (3+2//t)) of sparser spanners than was previously attainable. We also provide efficient parallel constructions. Our algorithms are based on new structures called pairwise-covers and a novel approach to construct them efficiently.
PRODUCE: A Probability-Driven Unequal Clustering Mechanism for Wireless Sensor Networks
Authors: Jung-Hwan Kim, Sajjad Hussain Chauhdary, Wen-Cheng Yang, Dong-Sub Kim, Myong-Soon Park
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

There has been proliferation of research on seeking for distributing the energy consumption among nodes in each cluster and between cluster heads to extend the network lifetime. However, they hardly consider the hot spots problem caused by heavy relay traffic forwarded. In this paper, we propose a distributed and randomized clustering algorithm that consists of unequal sized clusters. The cluster heads closer to the base station may focus more on inter-cluster communication while distant cluster heads concentrate more on intra-cluster communication. As a result, it nearly guarantees no communication in the network gets excessively long communication distance that significantly attenuates signal strength. Simulation results show that our algorithm achieves abundant improvement in terms of the coverage time and network lifetime, especially when the density of distributed nodes is high.
Modelling and Prediction of Internet Time-Delay by Feed-Forward Multi-layer Perceptron Neural Network
Authors: S. R. Seyed Tabib, Ali A. Jalali
Venue: Proceedings of the Tenth International Conference on Computer Modeling and Simulation (2008)

Internet time-delay prediction plays a key role in improving dynamic performance for many applications, especially for Internet-based tele-operation systems. Therefore, ideal prediction approach for Internet time-delay must be investigated emphatically. In this paper, after analayzing Internet time-delay, a new approach based on neural network is developed to predict the uncertain time-delay in the Internet. By using measured data between four Internet nodes and MATLAB environment, the feed-forward multi-layer perceptron (FMLP) neural network has been trained with single-step-ahead Prediction algorithm. Then, using validation data, the performance of the neural network was evaluated. It is shown that this neural network can predict time-delay based on their proper inputs.
Workflow Level Interoperation of Grid Data Resources
Authors: Tamas Kiss, Peter Kacsuk, Gabor Terstyanszky, Stephen Winter
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

The lack of widely accepted standards and the use of different middleware solutions divide today’s Grid resources into non-interoperable production Grid islands. On the other hand, more and more experiments require such a large number of resources that the interoperation of existing production Grids becomes inevitable. This paper, based on the current results of grid interoperation studies, defines generic requirements towards the workflow level interoperation of grid solutions. It concentrates on intra-workflow interoperation of grid data resources, as one of the key areas of generic interoperation, and describes through an example how existing tools can be extended to achieve the required level of interoperation.
An effort and time based measure of usability
Authors: Dan Tamir, Oleg V. Komogortsev, Carl J. Mueller
Venue: Proceedings of the 6th international workshop on Software quality (2008)

The hypothesis of this research is that usability relates to the physical effort that is required in order to use software in the accomplishment of interactive tasks. Implications of this hypothesis are significant since effort is an objective quantity that can be measured efficiently in a relatively non-expensive and non-invasive fashion. Based on this hypothesis, this work proposes metrics for measuring operability, learnability, and understandability. Usability testing is an essential element of a robust validation process. Nevertheless, evaluating software usability is an expensive and time consuming activity, frustrating both developers and managers. Developers are frustrated because it is a critical part of their work; yet, they do not have solid information on how to address it. Managerial frustration lies in the fact that correcting usability defects is an iterative process, and the amount of preparation required can significantly delay a project. Hence, wider utilization of usability testing requires reducing the cost and simplifying the approach. This paper proposes a framework for measuring effort and using the effort measurements to assess usability. The framework has two main components: One bases effort on keystrokes and mouse usage; the second uses a model of the eye muscles along with eye-movement tracking to estimate eye effort. The two components are independent, but they could be used in tandem. Tracking time and effort may not be as precise an evaluation of usability. Nevertheless, it can provide a good screening tool to reduce development cost.
Learning in Environments with Unknown Dynamics: Towards more Robust Concept Learners
Authors: Marlon Núñez, Raúl Fidalgo, Rafael Morales
Venue: The Journal of Machine Learning Research (2007)

In the process of concept learning, target concepts may have portions with short-term changes, other portions may support long-term changes, and yet others may not change at all. For this reason several local windows need to be handled. We suggest facing this problem, which naturally exists in the field of concept learning, by allocating windows which can adapt their size to portions of the target concept. We propose an incremental decision tree that is updated with incoming examples. Each leaf of the decision tree holds a time window and a local performance measure as the main parameter to be controlled. When the performance of a leaf decreases, the size of its local window is reduced. This learning algorithm, called OnlineTree2, automatically adjusts its internal parameters in order to face the current dynamics of the data stream. Results show that it is comparable to other batch algorithms when facing problems with no concept change, and it is better than evaluated methods in its ability to deal with concept drift when dealing with problems in which: concept change occurs at different speeds, noise may be present and, examples may arrive from different areas of the problem domain (virtual drift).
A short proof of K&ouml;nig's matching theorem
Authors: Romeo Rizzi
Venue: Journal of Graph Theory (2000)

We give a short proof of the following basic fact in matching theory: in a bipartite graph the maximum size of a matching equals the minimum size of a node cover. &copy; John Wiley & Sons, Inc. J Graph Theory 33: 138&ndash;139, 2000
Adaptive testing system modeled through fuzzy logic
Authors: J. Suarez-Cansino, R. A. Hernandez-Gomez
Venue: Proceedings of the 2nd WSEAS International Conference on Computer Engineering and Applications (2008)

This paper shows the main ideas behind a computerized adaptive testing system, where the item administration component is modelled through simple fuzzy logic concepts. The work introduces the idea of considering the examinees as members of fuzzy sets by defining some membership functions. These membership functions are defined by assuming the previous experience of the authors in several academic areas. In addition, it is also assumed that the item database contains questions belonging to fuzzy sets defined through the idea of item complexity. The rationale of the proposed item administration model considers the evaluation process as a control theory problem, by establishing a metaphor with a physical system from a kinematical point of view. In accordance with this physical model, fuzzy rules are proposed to the computer adaptive testing system, where some computer simulated results are also presented. Finally, this work suggests some useful ideas about the database design in a real computerized adaptive testing system.
On The Nature Of Formal System Decomposition Principles And Their Potential Applications To The Basis Of Carcinogenesis
Authors: Tolga Tuncer, Yalcin Tuncer, Murat M. Tanik
Venue: Journal of Integrated Design Process Science (2006)

The notion of complex systems and system decomposition principles are briefly reviewed. From the perspective of formal decomposition of systems and as an application of entropic principles, an attempt is made to open up a new avenue of investigation for carcinogenesis.
Cultural, sociological, and experiential challenges for CIS education
Authors: Jeffrey A. Stone, David P. Kitlan, Mark E. Hoffman, David R. Vance
Venue: Journal of Computing Sciences in Colleges (2008)

Enrollment in Computer and Information Science (CIS) majors have been dropping sharply since 2000 [5]. This decline poses untold ramifications for the nation's ability to maintain it's technological and research and development edge, leading to potential reductions in both economic and political security for the United States. Consequently, substantive research in CIS education has been performed to try and identify new methods of instruction and curriculum design intended to attract otherwise disinterested students to these majors. However, such research must consider the cultural, sociological, and experiential factors which influence student attitudes towards CIS majors and technology in general.
A parallel extended GCD algorithm
Authors: Sidi Mohamed Sedjelmaci
Venue: Journal of Discrete Algorithms (2008)

A new parallel extended GCD algorithm is proposed. It matches the best existing parallel integer GCD algorithms of Sorenson and Chor and Goldreich, since it can be achieved in O"@e(n/logn) time using at most n^1^+^@e processors on CRCW PRAM. Sorenson and Chor and Goldreich both use a modular approach which consider the least significant bits. By contrast, our algorithm only deals with the leading bits of the integers u and v, with u>=v. This approach is more suitable for extended GCD algorithms since the coefficients of the extended version a and b, such that au+bv=gcd(u,v), are deeply linked with the order of magnitude of the rational v/u and its continuants. Consequently, the computation of such coefficients is much easier.
Investigating the problems faced by older adults and people with disabilities in online environments
Authors: K. Curran, N. Walters, D. Robinson
Venue: Behaviour & Information Technology (2007)

Irresponsible and inaccessible web design causes unnecessary problems to certain website users. By applying the web content accessibility guidelines to a website the amount of possible users who can successfully view the content of that site will increase especially for those who are in the disabled and older adult categories of online users. We present the results of assessing the compliance of a selection of websites with guidelines set out by the Web Accessibility Initiative (WAI). It was found that most sites evaluated were inaccessible to those with disabilities. Only one of the selected sites passed all three priority levels set out by the WAI. In many cases, minor modifications to sites will make them accessible to people with disabilities. Therefore it can only be speculated that the reasons for lack of conformance may vary from lack of awareness of the issue, time constraints or the general stress of having to keep up with new technologies. Companies who overlook users with disabilities however may be doing so at long-term risk to their legal position, public image and ultimately business success.
Software Architecture (Advanced Topics in Science and Technology in China), 1 edition
Authors: Zheng Qin, Jian-Kuan Xing, Xiang Zheng
Venue:  (2008)

Part of the new series, Advanced Topics in Science and Technology in China, this book aims to introduce the theoretical foundations, various sub-fields, current research, and practical methods of software architecture. Readers can acquire basic knowledge of software architecture, including why software architecture is necessary, how we can describe a systems architecture with formal language, what architecture styles are popular in practice, and how we can apply software architecture to the development of systems. Case studies, data, illustrations, and other materials released within the past 5 years will be used to show the latest developments in software architecture. Dr. Qin Zheng is doctoral mentor of the computer science and technology departments at Tsinghua and Xian Jiaotong Universities. He has been Associate Dean of the School of Software, Tsinghua University, and Chair of the Institute of E-commerce, Xian Jiaotong University. He has been a visiting scholar at several universities in the United States.
It seemed like a good idea at the time
Authors: Jonas Boustedt, Robert McCartney, Josh Tenenberg, Scott D. Anderson, Caroline M. Eastman, Daniel D. Garcia, Paul V. Gestwicki, Margaret S. Menzin
Venue: Proceedings of the 39th SIGCSE technical symposium on Computer science education (2008)

We often learn of successful pedagogical experiments, but we seldom hear of the the ones that failed. For this special session we solicited submissions from the SIGCSE membership, selected the best from among these, and will have presentations at the session by the selected authors. Our contributions describe pedagogical approaches that seemed to be good ideas but turned out as failures. Contributors will describe their pedagogical experiment, the rationale for the experiment, evidence of failure, and lessons learned.
Comprehensive evaluation criteria for English learning websites using expert validity surveys
Authors: Ya-Ting C. Yang, Chia-Ying Chan
Venue: Computers Education (2008)

This study aimed to develop a set of evaluation criteria for English learning websites. These criteria can assist English teachers/web designers in designing effective websites for their English courses and can also guide English learners in screening for appropriate and reliable websites to use in increasing their English ability. To fulfill our objective, we employed a three-phase research procedure: (a) establishing a preliminary set of criteria from a thorough review of the literature, (b) evaluating and refining the preliminary criteria by conducting interviews with in-service teachers and learners, and (c) validating and finalizing the criteria according to expert validity surveys. The established criteria have 46 items, classified into 6 categories (the number of items within the category) - general information (12), integrated English learning (13), listening (4), speaking (6), reading (5), and writing (6). The general information evaluates the authority, accuracy, and format of the learning websites. The integrated English learning evaluates the overall information relevant to English learning materials as well as the common features of the four language skills. The criteria for listening, speaking, reading, and writing, for example, examine the suitable intonation, skills of discourse, classification of reading articles by their attributes, and the proper use of discussion boards for students when practicing their writing skills. Based on qualitative and quantitative analysis of the interviews and expert validity surveys, we confirmed the effectiveness of the developed evaluation criteria with satisfactory indexes of inter-rater reliability, content validity, and factorial validity.
An upper bound model for TCP and UDP throughput in IPv4 and IPv6
Authors: Eric Gamess, Rina Surós
Venue: Journal of Network and Computer Applications (2008)

Due to the shortage of public IPv4 addresses, the IETF has developed a new version of the Internet Protocol called IPv6. Many institutions all over the world had already started the migration to IPv6. Since this migration has to be done slowly, the first step is the coexistence of the two protocols (IPv4 and IPv6) for some years. One important issue for IPv6 to gain acceptance, is its performance in end-user applications. Hence, due to the availability of a variety of IPv6 implementations on different operating systems, it is important to evaluate the performance of the different IPv6 stacks, and compare it to the one shown by IPv4. In this paper, we present an upper bound model to compute TCP and UDP throughput for IPv4 and IPv6, in a full-duplex point-to-point connection. Our model can be used for any variant of Ethernet technology (10, 100, and 1000Mbps). To validate this model, we did experiments and compared the maximum theoretical throughput with the experimental ones. Experiments were done with Windows XP SP2, Solaris 10, and Debian 3.1, which are very popular operating systems. The results show that 10Mbps Ethernet technology is already very mature, since it gave performance very close to the maximum theoretical throughput. Experiments with FastEthernet (100Mbps) show a TCP and UDP throughput close to the maximum theoretical throughput, especially for large payload. In the case of GigaEthernet (1000Mbps), experimental results are not far from the maximum throughput for large TCP and UDP payload. However, for small TCP and UDP payload, the differences between our model (the maximum throughput) and the experiments are important. These differences should significantly decrease with the release of faster technology (processors and RAM).
Best approximation and moduli of smoothness: Computation and equivalence theorems
Authors: Sergey Tikhonov
Venue: Journal of Approximation Theory (2008)

In this paper we investigate the trigonometric series with the @b-general monotone coefficients. First, we study the uniform convergence criterion. The estimates of best approximations and moduli of smoothness of the series in uniform metrics are obtained in terms of coefficients. These results imply several important relations between moduli of smoothness of different orders (in particular, Marchaud-type inequality) and best approximations.
CMOS current-steering DAC architectures based on the triple-tail cell
Authors: Alfio Dario Grasso, Carmelo Alessandro Mirabella, Salvatore Pennisi
Venue: International Journal of Circuit Theory and Applications (2008)

In this paper two novel current-steering digital-to-analog converter (DAC) architectures, exploiting the triple-tail cell as switching element, are presented. The proposed solutions are theoretically analysed and design equations are carried out. The two architectures show better performance than the classical binary-weighted solution and it is shown that they can profitably substitute the binary sub-DAC section in a segmented topology. Theoretical results are compared with behavioural-level simulations and confirm the effectiveness of the proposed architectures. Copyright &copy; 2007 John Wiley & Sons, Ltd.
A designerly critique on enchantment
Authors: Philip R. Ross, C. J. Overbeeke, Stephan A. Wensveen, Caroline M. Hummels
Venue: Personal and Ubiquitous Computing (2008)

To develop the concept of user experience in HCI, McCarthy et al. introduce the notion of enchantment in interaction design. They describe five sensibilities that support exploration and evaluation in design for enchantment. In this paper, we discuss design for enchantment in light of our approach to design for interaction, called design for meaningful mediation. Based on our experiences from case studies, we argue that `considering the whole person with feelings, desires and anxieties', one of the sensibilities McCarthy et al. formulate, influences the desirability and realisation of the other four sensibilities. By way of case studies, we show how we explored the link between `the whole person' and desired interaction experience in a designerly way. We place enchantment in a context of other interaction experiences and demonstrate possible design techniques relevant to design for interaction experiences, including enchantment.
Packet Loss Process in a Queue with Markovian Arrivals
Authors: Andrzej Chydzinski
Venue: Proceedings of the Seventh International Conference on Networking (2008)

In this report, a detailed analysis of the packet loss process in a finite-buffer queue fed by the Markovian arrival process (MAP) is shown. The results consist of both transient and stationary characterization of the loss process in terms of the loss ratio, the number of packets lost per time unit and the number of losses in an interval of a given length. In addition to the analytical results, a number of numerical examples based on an IP traffic trace file are presented.