ppxscal/embedding_network huggingface dataset:
Pluggable parallelisation
Authors: Rui C. Gonçalves, João L. Sobral
Venue: Proceedings of the 18th ACM international symposium on High performance distributed computing (2009)

This paper presents the concept of pluggable parallelisation that allows scientists to develop sequential like codes that can take advantage of multi-core, cluster and grid systems. In this approach parallel applications are developed by plugging parallelisation patterns/idioms into scientific codes (e.g., sequential like codes), softening the move from sequential to parallel programming and promoting the separation between domain specific code and parallelisation issues. Pluggable parallelisation combines three characteristics: 1) parallelisation is performed from outside to inside, localising parallelisation concerns into well defined modules, reducing changes required to the domain specific code and avoiding invasive parallelisation of base code; 2) control view is separated from data view promoting a stronger separation of concerns which improves reuse of parallelisation concerns across platforms and enables fine-grained refinements; and 3) abstractions can be composed, supporting the development of more complex patterns based on fine-grained features. This paper presents the concept of pluggable parallelisation and shows how some well known parallelisation strategies can be implemented in this approach. Results show that this is a feasible approach and performance is competitive with traditional parallel programming.
Post-placement interconnect entropy
Authors: Wenyi Feng, Jonathan W. Greene
Venue: IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2007)

We introduce the concept of post-placement interconnect entropy: the minimal number of bits required to describe a well-placed netlist, which has connection lengths distributed according to Rent's rule. The entropy is a function of the number N of cells in the netlist and the Rent exponent p. We derive an expression for the entropy per cell and show that it converges as N approaches infinity. The entropy provides an achievable lower bound on the number of configuration bits in a programmable logic device (PLD) [or field-programmable gate array (FPGA)] and a useful measure of its routing flexibility. Specific numerical values are computed for practical situations. For example, any scalable FPGA composed of 4-input lookup table cells would require 31 configuration bits per cell. We compare this to the actual number of configuration bits in a standard FPGA architecture. We generalize the bound to dimensions higher than two, and show that for any p there is an optimal dimension that minimizes the bound.
Size of random Galois lattices and number of closed frequent itemsets
Authors: Richard Emilion, Gérard Lévy
Venue: Discrete Applied Mathematics (2009)

Given a sample of binary random vectors with i.i.d. Bernoulli(p) components, that is equal to 1 (resp. 0) with probability p (resp. 1-p), we first establish a formula for the mean of the size of the random Galois lattice built from this sample, and a more complex one for its variance. Then, noticing that closed @a-frequent itemsets are in bijection with closed @a-winning coalitions, we establish similar formulas for the mean and the variance of the number of closed @a-frequent itemsets. This can be interesting for the study of the complexity of some data mining problems such as association rule mining, sequential pattern mining and classification.
Direct-to-Consumer Advertising of Prescription Drugs: A Strategic Analysis
Authors: Wilfred Amaldoss, Chuan He
Venue: Marketing Science (2009)

Consumers cannot purchase a prescription drug without a prescription from a physician, yet many prescription drugs are promoted to consumers with the help of direct-to-consumer (DTC) advertising. In this paper, we propose and test a competitive model of DTC advertising. We find that the brand specificity of DTC advertising can have an inverted U-shaped relationship with detailing, DTC advertising, and profits. Furthermore, an increase in the cross-price sensitivity between competing prescription drugs is not always detrimental to firm profits. A laboratory test lends qualitative support to some of our model predictions. We also discuss potential implications of DTC advertising for generic drugs and over-the-counter drugs.
Visual equivalence: a new standard of image fidelity for computer graphics
Authors: Kavita Bala
Venue:  (2008)

Determining the visual fidelity of an image is a fundamental problem in computer graphics. When is an image good enough; i.e. when does it convey a convincing representation of a scene? Most graphics algorithms either aim to compute a physically accurate solution matching the real world, or they leave judgments of fidelity entirely up to the end user. The former is often computationally intractable, and the latter is ad-hoc since it cannot be generalized or predicted. In this dissertation, we chart a new course between these two approaches. We propose visual equivalence, a new standard of image fidelity that focuses on what is visually important to the observer: the appearance of the scene, consisting of impressions of shapes, materials, and lighting. Under visual equivalence, an image with noticeable, pixel-by-pixel differences from a perfect reference can still be a high fidelity representation of the same scene, provided it conveys the same impression of scene appearance. This appearance-preserving standard is, to our knowledge, the first approach to image fidelity that permits judgments of this kind. We present an end-to-end psychophysical and algorithmic investigation of visual equivalence, and its impact on scene modeling and rendering in computer graphics. For natural illumination, we measure the degree to which representations of lighting can be approximated or manipulated without affecting object appearance, and demonstrate how the resulting metrics can motivate new algorithms resulting in improved speedup and compression for rendering. For complex aggregate geometry, we investigate how different combinations of object shapes and colors affect appearance, and derive thresholds that can be used to reduce scene complexity. Finally, for texture, we describe how texture synthesis can be characterized in terms of visual equivalence, and present an efficient synthesis algorithm for a range of constrained synthesis applications, including the synthesis of visually equivalent detail to enhance low-resolution images. This research takes some important first steps into a large new space in perceptually based rendering and modeling, which can address the challenges of future complex scenes in computer graphics.
Information Modelling and Knowledge Bases for Interoperability Solution in Security Area
Authors: Ladislav Buřita, Vojtěch Ondryhal
Venue: Proceeding of the 2008 conference on Information Modelling and Knowledge Bases XIX (2008)

The article presents an example of information interoperability solution in a security field. NEC, transformation concept based on wide ICT utilisation, forms a framework for such endeavour. Results of information modelling developed in MIP group, including IEDM and development method, are introduced. It looks however, that IEDM reached its limits. New forward-looking approaches, like domain modeling or knowledge technologies, will be applied in the near future. The aim of our project is a verification of knowledge approach possibilities based on ITM software.
SolarStore: enhancing data reliability in solar-powered storage-centric sensor networks
Authors: Yong Yang, Lili Wang, Dong Kun Noh, Hieu Khac Le, Tarek F. Abdelzaher
Venue: Proceedings of the 7th international conference on Mobile systems, applications, and services (2009)

In this paper, we present a reliable storage service, called SolarStore, that adaptively trades-off storage reliability versus energy consumption in solar-powered sensor networks. SolarStore adopts a predominantly disconnected network model, where long-running data-collection experiments are conducted in the absence of a continuous connection to the outside world. SolarStore (i) replicates data in the network until the next upload opportunity, and (ii) adapts the degree of data replication dynamically depending on solar energy and storage availability. The goal is to maximize the amount of data that can eventually be retrieved from the network subject to energy and storage constraints. Maximization of retrievable data implies minimizing sensing blackouts due to energy depletion as well as minimizing loss due to node damage in harsh environmental conditions. We have deployed an outdoor solar-powered sensor network, on which SolarStore is implemented and tested. An indoor testbed is also set up for performance evaluation under environmental conditions not attained locally. Experiments show that SolarStore is successful in dynamically responding to variations in the environment in a manner that increases retrievable data under different node failure scenarios.
Smart Ride Seeker Introductory Plan
Authors: Sameh Abdel-Naby, Paolo Giorgini
Venue: Proceeding of the 2006 conference on STAIRS 2006: Proceedings of the Third Starting AI Researchers' Symposium (2006)

Based on the use of location and available car seats, Car sharing systems allowed a substantial number of people to share car rides.This paper proposes the initial phase of Smart Ride Seeker (SRS), which is a Car Pooling-like technique for distributing resources among a community. This paper develops the SRS technique through a mobile-based application that allows the mapping of ride seekers' locations along with the locations of available cars on a graphical interface/map, giving the possibility to calculate the optimal path for both the ride giver and seeker to fulfill their demands.
On general construction for extended visual cryptography schemes
Authors: Daoshun Wang, Feng Yi, Xiaobo Li
Venue: Pattern Recognition (2009)

Numerous visual cryptography schemes (VCSs) have been proposed to protect a secret image with share images. Most VCSs use random-looking shares to code a single binary secret image. Some schemes are designed for color secret images. Droste's [New results on visual cryptography, in: Advances in Cryptology-CRYPTO '96, Lecture Notes in Computer Science, vol. 1109, Springer, Berlin, 1996, pp. 401-415] (n,n)-VCS is introduced for multiple binary secret images. Extended VCS (EVCS), by Ateniese et al. [Extended capabilities for visual cryptography, Theoretical Computer Science 250 (2001) 143-161], for binary secret image uses meaningful (innocent-looking) shares. In this paper, we start with a more concise derivation of matrix extension in the ECVS model. This is implemented by concatenating an extended matrix to each basis matrix. We then present a general construction method for single or multiple binary/grayscale/color secret images using matrix extension utilizing meaningful shares. The result (k,n)-visual secret sharing schemes are more general than most existing schemes in terms of the secret/share image types. Using our matrix extension algorithm, any existing VCS with random-looking shares can be easily modified to utilize meaningful shares. The effectiveness of our schemes is demonstrated by real examples.
Combined evolution of level sets and B-spline curves for imaging
Authors: M. Fuchs, B. J&#x00fc;ttler, O. Scherzer, H. Yang
Venue: Computing and Visualization in Science (2009)

We propose the evolution of curves in direction of their unit normal using a combined implicit and explicit spline representation according to a given velocity field. In the implicit case we evolve a level set function for segmentation and geometry reconstruction in 2D images. The level set approach allows for topological changes of the evolving curves. The evolution of the explicit B-spline curve is driven by the Mumford&#x2013;Shah functional. We are mainly concerned with the segmentation of images using active contours. To get satisfactory results from the implicit evolution the optimal stopping time and the correct level of the evolving function has to be estimated. We overcome this problem by using the combined evolution.
Geometric and Optical Flow Based Method for Facial Expression Recognition in Color Image Sequences
Authors: Ayoub Al-Hamadi, Robert Niese, Saira S. Pathan, Bernd Michaelis
Venue: Proceedings of the International Conference on Computer Vision and Graphics: Revised Papers (2008)

This work proposes new static and dynamic based methods for facial expression recognition in stereo image sequences. Computer vision 3-d techniques are applied to determine real world geometric measures and to build a static geometric feature vector. Optical flow based motion detection is also carried out which delivers the dynamic flow feature vector. Support vector machine classification is used to recognize the expression using geometric feature vector while k-nearest neighbor classification is used for flow feature vector. The proposed method achieves robust feature detection and expression classification besides covering the in/out of plane head rotations and back and forth movements. Further, a wide range of human skin color is exploited in the training and the test samples.
Research Note---The Traveling Salesman Goes Shopping: The Systematic Deviations of Grocery Paths from TSP Optimality
Authors: Sam K. Hui, Peter S. Fader, Eric T. Bradlow
Venue: Marketing Science (2009)

We examine grocery shopping paths using the traveling salesman problem (TSP) as a normative frame of reference. We define the TSP-path for each shopper as the shortest path that connects all of his purchases. We then decompose the length of each observed path into three components: the length of the TSP-path, the additional distance because of order deviation (i.e., not following the TSP-order of category purchases), and the additional distance because of travel deviation (i.e., not following the shortest point-to-point route). We explore the relationship between these deviations and different aspects of in-store shopping/purchase behavior. Among other things, our results suggest that (1) a large proportion of trip length is because of travel deviation; (2) paths that deviate substantially from the TSP solution are associated with larger shopping baskets; (3) order deviation is strongly associated with purchase behavior, while travel deviation is not; and (4) shoppers with paths closer to the TSP solution tend to buy more from frequently purchased product categories.
Cost reduction on roots pre-isolation
Authors: Calin Alexe Muresan
Venue: Proceedings of the 8th WSEAS international conference on Artificial intelligence, knowledge engineering and data bases (2009)

The paper presents the?results of our research on Mahler measure and the polynomial discriminant, on "roots localization" and "minimum roots separation", on complex polynomials and polynomials having all real roots. We shall obtain the cost for pre-isolating polynomial real roots, in general and for particular cases, and we shall emphasize the improvement consisting in cost reduction for roots' pre-isolating and isolating.
Dynamic compensation of nonlinear dynamics research of mechanic anthropomorphic robotic hand
Authors: Yuriy Tsepkovskiy, Lyubomir Antonov, Frank Palis
Venue: Proceedings of the 10th WSEAS international conference on Automation & information (2009)

In this article two methods for control of scheme with compensation of nonlinear dynamics for manipulator with seven degrees of freedom are compared: PID control and adaptive fuzzy sliding mode control for variable value of gear ratio. The problem of system stability is concerned when there are constrains of control signal and disturbances of the control system quality.
An unstructured grid Reynolds stress model for separated turbulent flow simulations
Authors: Emre Alpman, L. N. Long
Venue: International Journal of Computational Fluid Dynamics (2009)

Most of the turbulence models in the literature contain simplified assumptions which make them computationally inexpensive but of limited accuracy for the solution of separated turbulent flows. Dramatic improvements in computer processing speed and parallel processing make it possible to use more complete models, such as Reynolds Stress Models, for separated turbulent flow simulations, which is the focus of this work. The Reynolds Stress Model consists of coupling the Reynolds transport equations with the Favre-Reynolds averaged Navier-Stokes equations, which results in a system of 12 coupled non-linear partial differential equations. The solutions are obtained by running the PUMA_RSM computational fluid dynamics code on unstructured meshes. The equations are solved all the way to the wall without using any wall functions. Results for high Reynolds number flow around a 6:1 prolate spheroid and a Bell 214ST fuselage are presented. For the prolate spheroid basic flow features such as cross-flow separation are simulated. Predictions of circumferential locations of cross flow separation points are in good agreement with the experiment. A grid refinement study is performed to improve the computations. The fine mesh solution predicted locations of primary and secondary separation points with errors of roughly 2° and 0°, respectively. Flow simulations around an isolated Bell 214ST helicopter fuselage were also performed. Predicted pressure and drag force correlate well with the wind tunnel data, with a less than 10% deviation from the experiment. Drag predictions also show relative speed of Reynolds Stress Model compared to Large Eddy Simulation to compute time averaged quantities. For numerical solutions parallel processing is applied with the MPI communication standard. The code used in this study is run on Beowulf clusters. The parallel performance of the code PUMA_RSM is analysed and presented.
Bus schedule interfered by traffic lights
Authors: Wei-neng Huang
Venue: Proceedings of the 10th WSEAS international conference on Mathematical methods, computational techniques and intelligent systems (2008)

We study the time-headway distributions of bus transportation interfered by the operation of traffic lights. We develop a simple mean-filed theory and carry out empirical measurements. We show that the time-headway distribution can be modified significantly by a nearby traffic light. As the distribution is quite peculiar, we conclude that the averaged time-headway conveys little information for the passengers waiting by the bus stop to estimate the arriving time of next bus.
Quadrature Amplitude Modulation for Differential Space-Time Block Codes
Authors: Christian Fellenberg, Hermann Rohling
Venue: Wireless Personal Communications: An International Journal (2009)

Differential Space-Time Block Codes (DSTBC) do not require any radio channel measurement and channel state information neither on the transmitter nor at the receiver side. Therefore, they are an attractive alternative to coherent Multiple-Input Multiple-output (MIMO) systems. The classical technical proposal for differential techniques is based on M-ary phase shift keying (M-PSK) modulation schemes for DSTBC (PSK-DSTBC). One advantage of this scheme is the constant envelop of the transmit signal, but it is well known that higher-order PSK is less efficient due to the small distance between adjacent points in the constellation diagram. Therefore, in this paper an alternative modulation technique for DSTBC is discussed, which is based on quadrature amplitude modulation (QAM-DSTBC). The signal envelope of the transmit signal is not any more constant in this case. Therefore, the technical challenge of integrating QAM into the DSTBC system design is to control the transmit power in order to avoid an increase or a decrease in transmit power to some extreme values. The mechanism, which is used in this paper to control the transmit power is based on an extension of the original QAM constellation diagram. The additional points, which are integrated into the constellation diagram are used in this case for the mapping procedure to select one of the modulation symbols with high or alternatively low signal power. This means for each single bit pattern there are almost always two modulation symbols available in the mapping procedure one with low and one with high signal power, which gives the basis for a signal power control algorithm. The resulting bit-error-rate (BER) performance of QAM-DSTBC is compared finally to the performance figures of the original proposal of PSK-DSTBC.
Specifying the personalization reasoning mechanism for an intelligent medical e-learning system on Atheromatosis: an empirical study
Authors: Katerina Kabassi, Maria Virvou, George A. Tsihrintzis, Yiannis Vlachos, Despina Perrea
Venue: Intelligent Decision Technologies (2008)

Computer-based education has already been acknowledged as an important asset for medical education. For example, web-based educational systems for medicine and health provide an additional important advantage to remote learners through platform- and time-independence. However, such systems are difficult to create as they require a lot of effort from both medical tutors and software engineers. Therefore, repetition of effort has to be avoided and such systems should be able to be used to their full extent from whoever requires medical and health knowledge on the specific topics. This means that they need to incorporate intelligent techniques in order to be able to adapt dynamically to the needs of individual users rather than have many static educational systems designed solely for different kinds of users. In view of this, in this paper we address the problem of developing an adaptive e-learning system for the medical domain of Atheromatosis. Atheromatosis of the aortic arch has been recognized as an important source of embolism, which is a frequent cause of stroke. This is the main reason that the particular topic is of interest to a wide range of users with different background knowledge and needs (e.g. medical students, nurses, common people interested in maintaining a good health, etc.). The inference mechanism of the system uses a combination of rule-based reasoning and a decision making theory. In order to design the reasoning mechanism of the system, and thus incorporate the decision making theory successfully, we conducted an empirical study. The empirical study involved distribution of questionnaires to several classes of potential users of an e-learning system about Atheromatosis and analysis of the results by computer and medical experts. The results of the empirical study were used for designing the reasoning mechanism of the system.
Improving Chen and Han's algorithm on the discrete geodesic problem
Authors: Shi-Qing Xin, Guo-Jin Wang
Venue: ACM Transactions on Graphics (TOG) (2009)

The computation of geodesic distances or paths between two points on triangulated meshes is a common operation in many computer graphics applications. In this article, we present an exact algorithm for the single-source all-vertices shortest path problem. Mitchell et al. [1987] proposed an O(n2 log n) method (MMP), based on Dijkstra's algorithm, where n is the complexity of the polyhedral surface. Then, Chen and Han [1990] (CH) improved the running time to O(n2). Interestingly Surazhsky et al. [2005] provided experimental evidence demonstrating that the MMP algorithm runs many times faster, in practice, than the CH algorithm. The CH algorithm encodes the structure of the set of shortest paths using a set of windows on the edges of the polyhedron. Our experiments showed that in many examples over 99&percnt; of the windows created by the CH algorithm are of no use to define a shortest path. So this article proposes to improve the CH algorithm by two separate techniques. One is to filter out useless windows using the current estimates of the distances to the vertices, the other is to maintain a priority queue like that achieved in Dijkstra's algorithm. Our experimental results suggest that the improved CH algorithm, in spite of an O(n2 log n) asymptotic time complexity, greatly outperforms the original CH algorithm in both time and space. Furthermore, it generally runs faster than the MMP algorithm and uses considerably less space.