ppxscal/embedding_network huggingface dataset:
Usability testing using physiological analysis
Authors: Rita A. Sperry, John D. Fernandez
Venue: Journal of Computing Sciences in Colleges (2008)

Because traditional measures employed in usability testing are inherently subjective, it is necessary to develop an objective method for evaluating the usability of a system. This paper describes a project that used physiological analysis to quantify the ease of use of a Web site, specifically concentrating on the effect of color combinations on the user's bodily processes. Testing of the system reveals that there is a definite correlation between the results of physiological analysis and subjective user satisfaction surveys. Thus, physiological analysis results can be used in the place of contrived values to assess the usability of a system.
New upper bounds for the chromatic number of a graph
Authors: Ladislav Stacho
Venue: Journal of Graph Theory (2001)

We show that for any graph G, the chromatic number &chi;(G)&thinsp;&le;&thinsp;&Delta;2(G)&thinsp;+&thinsp;1, where &Delta;2(G) is the largest degree that a vertex &nu; can have subject to the condition that &nu; is adjacent to a vertex whose degree is at least as big as its own. Moreover, we show that the upper bound is best possible in the the following sense: If &Delta;2(G)&thinsp;&ge;&thinsp;3, then to determine whether &chi;(G)&thinsp;&le;&thinsp;&Delta;2(G) is an NP-complete problem. &copy; 2001 John Wiley & Sons, Inc. J Graph Theory 36: 117&ndash;120, 2001 A part of the paper was prepared during a postdoc fellowship of the author at the Department for Computer Science, University of Turku, TUCS, Finland.
Distribution of visual attention in head-worn displays
Authors: Anke Huckauf, Mario H. Urbina, Fabina Doil, Johannes Tümler, Rüdiger Mecke
Venue: Proceedings of the 5th symposium on Applied perception in graphics and visualization (2008)

With head-worn displays, information can be presented in addition to the real surround. But, the virtual information is self-illuminating, has an unclear depth, and, depending on the visual background, the signal-noise ratio and the brightness contrast varies. We examined performance in a visual search task in which a 0 had to be found under O. The head-worn display was placed in front of the monitor so that the stimuli covered the same parts of the visual field. Performance on the head-worn display was worse than on the monitor. Searching a mixed display (half of the stimuli occurred on the monitor, half on the head-worn display) took more time than expected by unitary performances. These costs must be attributed to switching between both media. The results suggest that the distribution of attention in depth is restricted.
Two sufficient conditions for dominating cycles
Authors: Mei Lu, Huiqing Liu, Feng Tian
Venue: Journal of Graph Theory (2005)

A cycle C of a graph G is dominating if each component of $G\backslash C$ is edgeless. In the paper, we will give two sufficient conditions for each longest cycle of a 3-connected graph to be a dominating cycle. &copy; 2005 Wiley Periodicals, Inc. J Graph Theory
Teaching push-down automata and turing machines
Authors: César García-Osorio, Iñigo Mediavilla-Sáiz, Javier Jimeno-Visitación, Nicolás García-Pedrajas
Venue: ACM SIGCSE Bulletin (2008)

In this paper we present the new version of a tool to assist in teaching formal languages and automata theory. In the previous version the tool provided algorithms for regular expressions, finite automata and context free grammars. The new version can simulate as well push-down automata and Turing machines.
A note on biorthogonal ensembles
Authors: Patrick Desrosiers, Peter J. Forrester
Venue: Journal of Approximation Theory (2008)

We study multiple orthogonal polynomials in the context of biorthogonal ensembles of random matrices. In these ensembles, the eigenvalue probability density function factorizes into a product of two determinants while the eigenvalue correlation functions can be written as a determinant of a kernel function. We show that the kernel is itself an average of a single ratio of characteristic polynomials. In the same vein, we prove that the type I multiple polynomials can be expressed as an average of the inverse of a characteristic polynomial. We finally introduce a new biorthogonal matrix ensemble, namely the chiral unitary perturbed by a source term, whose multiple polynomials are related to the modified Bessel function of the first kind.
Evaluation of Quality Attribute Variability in Software Product Families
Authors: Leire Etxeberria, Goiuria Sagardui
Venue: Proceedings of the 15th Annual IEEE International Conference and Workshop on the Engineering of Computer Based Systems (2008)

Software product family or line is a software engineering paradigm that systematizes reuse. In Software Product Line Engineering, two phases are distinguished: Domain Engineering which is in charge of developing a common infrastructure and assets and Application Engineering which makes use of those assets to generate the products. One of the key aspects of product lines is variability and its management. However, the main focus has been on functional variability and quality variability in software product lines has not received so much attention by researchers. In a product line different members of the line may require different levels of a quality requirement, for instance they could differ in terms of their availability, security, reliability, etc. Due to this variability, quality evaluation in software product lines is much more complicated that in single-systems. One alternative is to evaluate all the products of a line but it is very expensive and ways of reducing evaluation efforts are necessary. In this direction, the paper presents a method for facilitating cost-effective quality evaluation of a product line taking into consideration variability on quality attributes.
On-line and post-processing timestamp correspondence for free-running clock nodes, using a network clock
Authors: Olivier Bezet, Véronique Cherfaoui
Venue: Real-Time Systems (2008)

Timestamp conversion is an important consideration in the deployment of distributed architectures. In this article we propose a precise, low-cost solution for on-line and post-processing timestamp conversion in distributed architectures, robust as regards the plugging and unplugging of hardware and the addition of new nodes (that is to say the different pieces of hardware connected to the network), not synchronized, and with no negative impact on the conversion quality. Each node (e.g., a computer) has at least one free-running clock. This clock's time is the reference for all events used by the node. When the local node needs to record the time of an event timestamped by a remote node, the time is converted from the remote node's time to the local node's time. Interval timestamping is used, to take account of time imperfections (e.g. sensor and computer latencies, or due to time conversion between the different computers). A network clock is used, enabling a precise conversion and avoiding exchanges of messages for the conversion of clock correspondences. Moreover, it allows an unlimited number of nodes in the network.
Koala: Ultra-Low Power Data Retrieval in Wireless Sensor Networks
Authors: Razvan Musaloiu-E., Chieh-Jan Mike Liang, Andreas Terzis
Venue: Proceedings of the 7th international conference on Information processing in sensor networks (2008)

We present Koala, a reliable data retrieval system designed to operate at permille (.1%) duty cycles, essential for long term environmental monitoring networks. Koala achieves these low duty cycles by letting the network's nodes sleep most of the time and reviving them through an efficient wake-up strategy whenever the gateway performs a bulk data download. Unlike other systems which consume energy to maintain consistent network state (\emph{e.g.} routes, sleep schedules, etc.) across the network's nodes, Koala maintains no persistent routing state on the motes. Instead, a basestation calculates the network paths using reachability information collected by the motes. The Flexible Control Protocol (FCP), a protocol we developed, is then used to install this routing information on the network's nodes. This paradigm of operation not only eliminates the overhead of maintaining routing state, but also significantly reduces the complexity of the networking code running on the motes. Results from simulation and an actual implementation on TinyOS 2 indicate that Koala can achieve very low duty cycles under a wide range of download and network sizes.
Siting and sizing of distributed generation units using GA and OPF
Authors: M. Hosseini Aliabadi, M. Mardaneh, B. Behbahan
Venue: Proceedings of the 2nd WSEAS International Conference on Circuits, Systems, Signal and Telecommunications (2008)

This paper deals with the important task of finding the optimal siting and sizing of Distributed Generation (DG) units for a given distribution network so that the cost of active and reactive power generation can be minimized. The optimization technique is based on Genetic Algorithm (GA) and Optimal Power Flow (OPF) calculations. Using the suggested technique of this paper, the search space of GA is limited and the optimum generation condition can be achieved. The proposed procedure has been applied to a distribution system and the results of simulations indicate that the application of the suggested technique can result in considerable savings.
Ad-Hoc Threshold Broadcast Encryption with Shorter Ciphertexts
Authors: Vanesa Daza, Javier Herranz, Paz Morillo, Carla Ràfols
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

In a threshold broadcast encryption scheme, a sender chooses (ad-hoc) a set of n receivers and a threshold t, and then encrypts a message by using the public keys of all the receivers, in such a way that the original plaintext can be recovered only if at least t receivers cooperate. This kind of scheme has many applications in mobile ad-hoc networks, characterized by their lack of infrastructure as well as for the high dynamism of their nodes. Threshold broadcast encryption schemes are much more appropriate for mobile ad-hoc scenarios than standard threshold public key encryption schemes, where the set of receivers and the threshold for decryption must be known in advance (and remain the same for the rest of the protocol). Previously proposed threshold broadcast encryption schemes have ciphertexts which contain at least n group elements. In this paper, we propose a new scheme where the ciphertexts contain essentially n-t group elements. The construction uses secret sharing techniques and the ElGamal public key cryptosystem as basic tools. We formally prove the security of the scheme, by reduction to the security of ElGamal cryptosystem.
The core concept for 0/1 integer programming
Authors: Sam Huston, Jakob Puchinger, Peter Stuckey
Venue: Proceedings of the fourteenth symposium on Computing: the Australasian theory - Volume 77 (2008)

In this paper we examine an extension of the core concept for the 0/1 Multidimensional Knapsack Problem (MKP) towards general 0/1 Integer Programming (IP) by allowing negative profits, weights and capacities. The core concept provides opportunities for heuristically solving the MKP, achieving higher quality solutions and shorter runtimes than general IP methods. We provide the theoretical foundations of the extended core concept and further provide computational experiments showing that we can achieve similar computational behavior for extended MKP instances with negative weights, profits and capacities.
Approximation method in finding optimum stratum depending on Neyman allocation applied on Beta distribution
Authors: R. Ahmad Mahir, H. A. M. Al-Khazaleh, T. M. M. Al-Kassab
Venue: Proceedings of the 12th WSEAS International Conference on Applied Mathematics (2007)

The problem of optimum stratification on the auxiliary variable y for Neyman allocation has been considered. A Taylor Expansion rule of finding approximately optimum strata boundaries and general formulas for stratum weight, stratum mean and variance mean depending on Neyman Allocation have been suggested for Beta distribution. A numerical investigation into the boundaries stratum and variance mean of Neyman allocation with respect to optimum allocation has also been made for different values to the parameter Beta distribution.
AONS-An obsolescence detection and notification service for Web archives and digital repositories
Authors: J. Curtis, P. Koerbin, P. Raftos, D. Berriman, J. Hunter
Venue: The New Review of Hypermedia and Multimedia (2007)

This paper describes the results of a collaboration between the University of Queensland, the Australian National University and the National Library of Australia which has developed and deployed an automatic obsolescence detection and notification service (AONS) for digital collections. AONS can be configured to run over different types of collections of digital objects-either institutional repositories (DSpace or Fedora) or Web archives such as the National Library's PANDORA ('Preserving and Accessing Networked DOcumentary Resources of Australia') Archive. This work represents a real-world implementation of the obsolescence detection and notification service originally developed within the University of Queensland's PANIC Project. PANIC (Preservation and Archival of New media and Interactive Collections) was a prototype system based on a semantic Web services architecture which was designed to semi-automate the preservation of digital collections. This paper describes how AONS can be configured to automatically monitor collections for format obsolescence and streamline the subsequent migration of 'at risk' digital objects to current recommended formats, enabling their long-term preservation and accessibility.
Analysis and implications of parasitic and screening effects on the high-frequency/RF performance of tunneling-carbon nanotube FETs
Authors: Chaitanya Kshirsagar, Mohamed N. El-Zeftawi, Kaustav Banerjee
Venue: Proceedings of the 45th annual Design Automation Conference (2008)

Intrinsic and parasitic capacitances play an important role in determining the high-frequency RF performance of devices. Recently, a new type of carbon nanotube field effect transistor (CNFET) based on tunneling principle has been proposed, which shows impressive device properties and overcomes some of the limitations of previously proposed CNFET devices. Although carbon nanotube based devices have been optimized for DC performance so far, little has been done to optimize them for high-frequency operation. In this paper, we present, detailed modeling and analysis of device geometry based intrinsic and parasitic capacitances of tunneling carbon nanotube field effect transistors (T-CNFETs) with both single nanotube as well as nanotube-array based channel. Based on the model, we analyze scaling of parasitic capacitances with device geometry for two different scaling scenarios of T-CNFETs. We show that in order to reduce the impact of parasitic capacitance, nanotube density has to be optimized. Furthermore, for the first time, we analyze various factors affecting the high-frequency/RF performance of back gated T-CNFETs and study the impact of parasitic and screening effects on the high-frequency/RF performance of these devices.
MRI brain image segmentation and bias field correction based on fast spatially constrained kernel clustering approach
Authors: Liang Liao, Tusheng Lin, Bi Li
Venue: Pattern Recognition Letters (2008)

A fast spatially constrained kernel clustering algorithm is proposed for segmenting medical magnetic resonance imaging (MRI) brain images and correcting intensity inhomogeneities known as bias field in MRI data. The algorithm using kernel technique implicitly maps image data to a higher dimensional kernel space in order to improve the separability of data and provide more potential for effectively segmenting MRI data. Based on the technique, a speed-up scheme for kernel clustering and an approach for correcting spurious intensity variation of MRI images have been implemented. The fast kernel clustering and bias field correcting benefit each other in an iterative matter and have dramatically reduced the time complexity of kernel clustering. The experiments on simulated brain phantoms and real clinical MRI data have shown that the proposed algorithm generally outperforms the corresponding traditional algorithms when segmenting MRI data corrupted by high noise and gray bias field.
Neural correlates of post-error slowing during a stop signal task: A functional magnetic resonance imaging study
Authors: Chiang-shan Ray Li, Cong Huang, Peisi Yan, Prashni Paliwal, Robert Todd Constable, Rajita Sinha
Venue: Journal of Cognitive Neuroscience (2008)

The ability to detect errors and adjust behavior accordingly is essential for maneuvering in an uncertain environment. Errors are particularly prone to occur when multiple, conflicting responses are registered in a situation that requires flexible behavioral outputs; for instance, when a go signal requires a response and a stop signal requires inhibition of the response during a stop signal task (SST). Previous studies employing the SST have provided ample evidence indicating the importance of the medial cortical brain regions in conflict/error processing. Other studies have also related these regional activations to postconflict/error behavioral adjustment. However, very few studies have directly explored the neural correlates of postconflict/error behavioral adjustment. Here we employed an SST to elicit errors in approximately half of the stop trials despite constant behavioral adjustment of the observers. Using functional magnetic resonance imaging, we showed that prefrontal loci including the ventrolateral prefrontal cortex are involved in post-error slowing in reaction time. These results delineate the neural circuitry specifically involved in error-associated behavioral modifications.
Maxflow Based Routing for Traffic Engineering and Sustained High Bitrate Applications
Authors: Jaiwant Mulik
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

We present a data routing mechanism based on graph-theoretic maximum flow algorithms. The goal is to maximize data flow between source and destination pairs. Though multiple paths are used for data transmission, the goal of this mechanism is primarily to maximize throughput rather than provide fault-tolerance or quality-of-service as with other multipath mechanisms. Challenges relating to selecting participating links and routers are identified and addressed. Implementation aspects of traditional maximum flow algorithm categories; path augmentation and preflow-push are discussed and the choice of preflow-push is motivated. Simulations give insight into the effect of the reported power-law growth of connectivity on maximum flow algorithms by showing that strict power-law growth in detrimental to throughput. Growth by addition of random links gives better overall throughput than power-law growth. Finally, we show that though packet reordering is extensive in a maximum flow session, the reordering is deterministic leading to the possibility of designing transport algorithms that can use this predictability in minimizing the effect on reordering sensitive applications.
A Model of Financial Market Dynamics with Heterogeneous Beliefs and State-Dependent Confidence
Authors: Carl Chiarella, Roberto Dieci, Laura Gardini, Lucia Sbragia
Venue: Computational Economics (2008)

In a simple model of financial market dynamics, we allow the price of a risky security to be set by a market maker depending on the excess demand of heterogeneous interacting traders, fundamentalists and chartists, who place their orders based upon different expectations schemes about future prices: while chartists rely on standard trend-based rules, fundamentalists are assumed to know the economic environment and to form their beliefs accordingly. As price moves away from the long-run fundamental, fundamentalists become less confident in their forecasts, and put increasing weight on a reversion towards the fundamental price. The resulting two-dimensional discrete time dynamical system can exhibit a rich range of dynamic scenarios, often characterized by coexistence of attractors. A simple noisy version of the model reveals a variety of possible patterns for return time series.
Symbolic optimization of algebraic functions
Authors: Masaaki Kanno, Kazuhiro Yokoyama, Hirokazu Anai, Shinji Hara
Venue: Proceedings of the twenty-first international symposium on Symbolic and algebraic computation (2008)

This paper attempts to establish a new framework of symbolic optimization of algebraic functions that is relevant to possibly a wide variety of practical application areas. The crucial aspects of the framework are (i) the suitable use of algebraic methods coupled with the discovery and exploitation of structural properties of the problem in the conversion process into the framework, and (ii) the feasibility of algebraic methods when performing the optimization. As an example an algebraic approach is developed for the discrete-time polynomial spectral factorization problem that illustrates the significance and relevance of the proposed framework. A numerical example of a particular control problem is also included to demonstrate the development.
Motion identification from image sequences: Information theory and pixel selection
Authors: C. Bruni, C. Ferrone, G. Koch, M. Lucchetti
Venue: Computers Mathematics with Applications (2008)

The paper deals with the issue of (possibly nonrigid) motion identification from a sequence of degraded images. In particular the central problem is the one of proper pixel selection: the information content of each pixel is the basis of the pixel selection procedure. After the general setting of the problem we give some identifiability conditions. Then the pixel selection procedure is presented. Finally, the procedure is validated against simulated images of moving objects. It appears, that is enough to process few percent of the total pixel number without any significant decrease of the estimation accuracy.
An Efficient Two-Phase Algorithm to Find Gene-Specific Probes for Large Genomes
Authors: Seung-Ho Kang, Mun-Ho Choi, In-Seon Jeong, Hyeong-Seok Lim
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

The accuracy of a DNA microarray is fairly dependent on the quality of probes it uses. Good probes should be specific to the respective target to avoid any cross-hybridization. Checking the specificity of a probe candidate is the most time-consuming task. We propose an efficient two-phase approach for finding genespecific probes. At the first phase, for each gene our approach screens out other genes which have substrings that cause probe candidates of the gene to be bad. At the second phase, it exactly filters out bad probe candidates of each gene by comparing to the screened genes. In the case of S. cerevisiae having 6343 genes, our preprocessing algorithm took about 28minutes to screen out all other genes for every gene guaranteeing more than 95% of accuracy. And filtering algorithm took less than one minute to find all genespecific probes of all genes.