ppxscal/embedding_network huggingface dataset:
Finite element approximation to nonlinear coupled thermal problem
Authors: Yanzhen Chang, Danping Yang, Jiang Zhu
Venue: Journal of Computational and Applied Mathematics (2009)

A nonlinear coupled elliptic system modelling a large class of engineering problems was discussed in [A.F.D. Loula, J. Zhu, Finite element analysis of a coupled nonlinear system, Comp. Appl. Math. 20 (3) (2001) 321-339; J. Zhu, A.F.D. Loula, Mixed finite element analysis of a thermally nonlinear coupled problem, Numer. Methods Partial Differential Equations 22 (1) (2006) 180-196]. The convergence analysis of iterative finite element approximation to the solution was done under an assumption of 'small' solution or source data which guarantees the uniqueness of the nonlinear coupled system. Generally, a nonlinear system may have multiple solutions. In this work, the regularity of the weak solutions is further studied. The nonlinear finite element approximations to the nonsingular solutions are then proposed and analyzed. Finally, the optimal order error estimates in H^1-norm and L^2-norm as well as in W^1^,^p-norm and L^p-norm are obtained.
On a Theorem of Bandt and Wang and Its Extension to&#x00a0;p2-tiles
Authors: Benoit Loridant, Jun Luo
Venue: Discrete Computational Geometry (2009)

We study tilings of the plane by a single prototile with respect to the lattice and to the crystallographic group p2. We are interested in the connection between the neighbors of a tile in the tiling and its topology. We show that lattice and p2-tiles always have at least six neighbors. We characterize self-affine tiles that are homeomorphic to a disk in a rather easy way by the set and number of neighbors of the central tile in the tiling. This extends the work of Bandt and Wang devoted to lattice self-affine disk-like tiles of the plane.
Construction of Large Constant Dimension Codes with a Prescribed Minimum Distance
Authors: Axel Kohnert, Sascha Kurz
Venue: Mathematical Methods in Computer Science: Essays in Memory of Thomas Beth (2008)

In this paper we construct constant dimension codes with prescribed minimum distance. There is an increased interest in subspace codes in general since a paper [13] by Kötter and Kschischang where they gave an application in network coding. There is also a connection to the theory of designs over finite fields. We will modify a method of Braun, Kerber and Laue [7] which they used for the construction of designs over finite fields to construct constant dimension codes. Using this approach we found many new constant dimension codes with a larger number of codewords than previously known codes. We finally give a table of the best constant dimension codes we found.
Large-Area Arrays of Pillar-Based Metal Nanostructures
Authors: V. Ovchinnikov, A. Shevchenko
Venue: Proceedings of the 2009 Third International Conference on Quantum, Nano and Micro Technologies (2009)

The fabrication method of metal nanostructure arrays on large-area (e.g., 4" in diameter) substrate is proposed and demonstrated. The method includes formation of self-organized mask, nanopillar preparation by reactive ion etching, and oblique angle metal deposition on the nanopillar sidewalls. The resulting structures have crescent shapes with controllable opening, thickness, diameter, and height. Due to geometrical asymmetry, the nanocrescents demonstrate anisotropy of optical properties and can be used in production of cheap and large-area metamaterials.
Anomaly-based bug prediction, isolation, and validation: an automated approach for software debugging
Authors: Martin Dimitrov, Huiyang Zhou
Venue: Proceeding of the 14th international conference on Architectural support for programming languages and operating systems (2009)

Software defects, commonly known as bugs, present a serious challenge for system reliability and dependability. Once a program failure is observed, the debugging activities to locate the defects are typically nontrivial and time consuming. In this paper, we propose a novel automated approach to pin-point the root-causes of software failures. Our proposed approach consists of three steps. The first step is bug prediction, which leverages the existing work on anomaly-based bug detection as exceptional behavior during program execution has been shown to frequently point to the root cause of a software failure. The second step is bug isolation, which eliminates false-positive bug predictions by checking whether the dynamic forward slices of bug predictions lead to the observed program failure. The last step is bug validation, in which the isolated anomalies are validated by dynamically nullifying their effects and observing if the program still fails. The whole bug prediction, isolation and validation process is fully automated and can be implemented with efficient architectural support. Our experiments with 6 programs and 7 bugs, including a real bug in the gcc 2.95.2 compiler, show that our approach is highly effective at isolating only the relevant anomalies. Compared to state-of-art debugging techniques, our proposed approach pinpoints the defect locations more accurately and presents the user with a much smaller code set to analyze.
Efficient probabilistic subsumption checking for content-based publish/subscribe systems
Authors: Aris M. Ouksel, Oana Jurca, Ivana Podnar, Karl Aberer
Venue: Proceedings of the ACM/IFIP/USENIX 2006 International Conference on Middleware (2006)

Efficient subsumption checking, deciding whether a subscription or publication is covered by a set of previously defined subscriptions, is of paramount importance for publish/subscribe systems. It provides the core system functionality---matching of publications to subscriber needs expressed as subscriptions---and additionally, reduces the overall system load and generated traffic since the covered subscriptions are not propagated in distributed environments. As the subsumption problem was shown previously to be co-NP complete and existing solutions typically apply pairwise comparisons to detect the subsumption relationship, we propose a 'Monte Carlo type' probabilistic algorithm for the general subsumption problem. It determines whether a publication/subscription is covered by a disjunction of subscriptions in O(k m d), where k is the number of subscriptions, m is the number of distinct attributes in subscriptions, and d is the number of tests performed to answer a subsumption question. The probability of error is problem-specific and typically very small, and sets an upper bound on d. Our experimental results show significant gains in term of subscription set reduction which has favorable impact on the overall system performance as it reduces the total computational costs and networking traffic. Furthermore, the expected theoretical bounds underestimate algorithm performance because it performs much better in practice due to introduced optimizations, and is adequate for fast forwarding of subscriptions in case of high subscription rate.
Extracting unique rows of a bounded degree array using tries
Authors: Douglas Comer
Venue: Proceedings of the May 19-22, 1980, national computer conference (1980)

An array with integer entries between 0 and d-1 has bounded degree d. This paper considers several algorithms for extracting the set of unique rows from a bounded degree array. For each algorithm considered, it gives the time, space, and I/O requirements, and an assessment of the types of applications for which the method is well-suited. It begins with four methods based on well known techniques and data structures, and goes on to propose a new algorithm which uses a form of digitial search tree known as a trie. It shows that the trie-based scheme has advantages over the other methods. Finally, it discusses some applications including computing a projection in a relational database system, and finding classes of isomorphic rows.
An optimized ant colony algorithm based on the gradual changing orientation factor for multi-constraint QoS routing
Authors: Hua Wang, Zhao Shi, Anfeng Ge, Chaoying Yu
Venue: Computer Communications (2009)

The ad hoc network has been attracting increasing attention of researchers owing to its good performance and special application. The search of route that satisfies such multi-constraints as delay, jitter and bandwidth in ad hoc network can facilitate the solution to multi-media transmission. The problem of multi-constraint is generally an NP-Hard problem. This paper deals with the problem by adding an orientation heuristic factor to the conventional ant colony algorithm, which enables the ant to get rid of the blindness at the initial stage of path searching. The ant in the modified algorithm not only makes use of the previous search findings, but also reduces the misguiding effect of pheromones on the irrelevant paths, thus overcoming the problem of slow convergence. The choice and the extent of the effect of the orientation heuristic factor in the modified algorithm is our focus, and the gradual changing orientation factors is also studied. The gradual changing orientation factor not only enables the ant to take advantage of direction to assist path search, but also adjust convergence speed and exactitude. Simulation results indicate that the modified algorithm can quickly find the feasible solution to the network routing problem. The method adopted can help find better solutions in shorter time.
Parameters effect on block transmission communication systems
Authors: Mohd Fadzil Ain, Farid Ghani, Mutamed Khatib, Syed Idris Syed Hassan
Venue: Proceedings of the 7th conference on Data networks, communications, computers (2008)

This paper shows the effect of the system parameters for three previously proposed systems that depend on the principle of transmitting the data in blocks. The main idea for the first system is to move all the signal processing operations needed to eliminate the effect of the time variant channel from the receiver to the transmitter and leave the receiver quite simple (pre-coding). The other two systems make some sharing for the signal processing between the transmitter and the receiver in different ratios to obtain some enhancement on the performance of the pre-coding system.
A Logical Approach to Constraint Satisfaction
Authors: Phokion G. Kolaitis, Moshe Y. Vardi
Venue: Complexity of Constraints: An Overview of Current Research Themes (2008)

Since the early 1970s, researchers in artificial intelligence (AI) have investigated a class of combinatorial problems that became known as constraint-satisfaction problems (CSP). The input to such a problem consists of a set of variables, a set of possible values for the variables, and a set of constraints between the variables; the question is to determine whether there is an assignment of values to the variables that satisfies the given constraints. The study of constraint satisfaction occupies a prominent place in artificial intelligence, because many problems that arise in different areas can be modelled as constraint-satisfaction problems in a natural way; these areas include Boolean satisfiability, temporal reasoning, belief maintenance, machine vision, and scheduling (cf. [Dec92a,Kum92,Mes89, Tsa93]). In its full generality, constraint satisfaction is an NP-complete problem. For this reason, researchers in artificial intelligence have pursued both heuristics for constraint-satisfaction problems and tractable cases obtained by imposing various restrictions on the input (cf. [MF93,Dec92a,DM94,Fro97,PJ97]).
Topology synthesis of thermomechanical compliant mechanisms with geometrical nonlinearities using meshless method
Authors: Yi-Xian Du, Li-Ping Chen, Qi-Hua Tian, Zheng-Jia Wu
Venue: Advances in Engineering Software (2009)

The element-free Galerkin (EFG) method, one of the important meshless methods, is integrated into topology optimization and a new topology optimization method for designing thermomechanical actuated compliant mechanisms with geometrical nonlinearities is presented. The meshless method is employed to discretize the governing equations and the bulk density field. Using meshless method to analyze the thermomechanical model is better consistent with the natural behavior of large-displacement compliant mechanisms than using the standard finite element method (FEM). The optimization formulation is developed using the SIMP and meshless methods. The nonlinear design sensitivity analysis is performed by incorporating the adjoint approach into the meshless method. The filtering of the sensitivity developed corrects the topology including few discontinuous scattered points. The geometrically nonlinear design sensitivity analysis is performed by incorporating the adjoint approach into the meshless method. The availability of the proposed method is demonstrated by designing compliant actuators in which both linear and nonlinear modeling are considered.
Computing Equiangular Lines in Complex Space
Authors: Markus Grassl
Venue: Mathematical Methods in Computer Science: Essays in Memory of Thomas Beth (2008)

We consider the problem of finding equiangular lines in complex space, i. e., sets of unit vectors such that the modulus of the inner product between any two vectors is constant. We focus on the case of d 2 such vectors in a space of dimension d which corresponds to so-called SIC-POVMs. We discuss how symmetries can be used to simplify the problem and how the corresponding system of polynomial equations can be solved using techniques of modular computation. The ACM Portal is published by the Association for Computing Machinery. Copyright © 2010 ACM, Inc. Terms of Usage Privacy Policy Code of Ethics Contact Us Useful downloads: Adobe Acrobat QuickTime Windows Media Player Real Player
MINERVA: Multimedia on the INtERnet for Virtual Arts
Authors: J. F. Diez Higuera, F. J. Diaz Pernas
Venue: Proceedings of the 1999 IEEE International Conference on Multimedia Computing and Systems - Volume 02 (1999)

This paper describes a design that implements a Virtual Museum for its access through Internet. It can not only provide the information so far available in the Web, but also allows a three-dimensional (3D) walk through the whole Museum, watching its collections, plus a presentation of single objects in 3D, with different resolutions according to each visitor interests and with a real possibility of visitor-object interaction. All this opens a wide new path of investigation, as it brings 3D into Internet and means a contribution to the increase of interactivity in Web pages.
A Set Coverage-based Mapping Heuristic for Scheduling Distributed Data-Intensive Applications on Global Grids
Authors: Srikumar Venugopal, Rajkumar Buyya
Venue: Proceedings of the 7th IEEE/ACM International Conference on Grid Computing (2006)

Data-intensive Grid applications need access to large datasets that may each be replicated on different resources. Minimizing the overhead of transferring these datasets to the resources where the applications are executed requires that appropriate computational and data resources be selected. In this paper, we introduce a heuristic for the selection of resources based on a solution to the Set Covering Problem (SCP). We then pair this mapping heuristic with the well-known MinMin scheduling algorithm and conduct performance evaluation through extensive simulations.
Optimal Sizing of a Stand-alone Wind/Photovoltaic Generation Unit using Particle Swarm Optimization
Authors: Ali Kashefi Kaviani, Hamid Reza Baghaee, Gholam Hossein Riahy
Venue: Simulation (2009)

A hybrid wind/photovoltaic generation system is designed to supply power demand. The aim of this design is minimization of the overall cost of the generation scheme over 20 years of operation. Full demand supply is modeled as constraint for optimization problem. Characteristic equations of the system components and solar radiation and wind speed datasets are assumed to be deterministic, i.e. uncertainties are ignored. The system's costs include investment, replacement, and operation and maintenance costs during 20 years of system lifetime. All system components are commercially available, and actual prices are used. Wind and radiation datasets are for the North West region of Iran (Ardebil province). A Particle Swarm Optimization (PSO) algorithm is used to solve the optimization problem. Results indicate superiority of the PSO algorithm, in terms of speed and convergence to global optimum solution, over a Genetic Algorithm that is conventionally exploited in literature.
Action-Based Environment Modeling for Maintaining Trust
Authors: Özgür Kafalı, Pınar Yolum
Venue: Trust in Agent Societies: 11th International Workshop, TRUST 2008, Estoril, Portugal, May 12 -13, 2008. Revised Selected and Invited Papers (2008)

In open multiagent systems, agents need to select whom to trust. Traditionally, this selection is done based on the models that are built for the agents in the system. After each interaction with others, agents update their models of others based on the outcome. However, building and maintaining accurate models is difficult especially before many interactions take place. Contrary to traditional modeling approaches, we propose to model the environment in terms of agents' actions and their effects, rather than building individual models for each agent. Based on the effects of its actions, each agent can modify its behavior appropriately. We evaluate our proposed approach in comparison to a traditional approach in the Agent Reputation and Trust (ART) Testbed simulation environment. The simulations compare the two approaches in terms of the accuracy of models, the effectiveness in finding trustworthy agents as well as the effort needed to build accurate models.
Accelerating statistical static timing analysis using graphics processing units
Authors: Kanupriya Gulati, Sunil P. Khatri
Venue: Proceedings of the 2009 Asia and South Pacific Design Automation Conference (2009)

In this paper, we explore the implementation of Monte Carlo based statistical static timing analysis (SSTA) on a Graphics Processing Unit (GPU). SSTA via Monte Carlo simulations is a computationally expensive, but important step required to achieve design timing closure. It provides an accurate estimate of delay variations and their impact on design yield. The large number of threads that can be computed in parallel on a GPU suggests a natural fit for the problem of Monte Carlo based SSTA to the GPU platform. Our implementation performs multiple delay simulations at a single gate in parallel. A parallel implementation of the Mersenne Twister pseudo-random number generator on the GPU, followed by Box-Muller transformations (also implemented on the GPU) is used for generating gate delay numbers from a normal distribution. The &mu; and &sigma; of the pin-to-output delay distributions for all inputs and for every gate, are obtained using a memory lookup, which benefits from the large memory bandwidth of the GPU. Threads which execute in parallel have no data/control dependencies on each other. All threads compute identical instructions, but on different data, as required by the Single Instruction Multiple Data (SIMD) programming semantics of the GPU. Our approach is implemented on a NVIDIA GeForce GTX 8800 GPU card. Our results indicate that our approach can obtain an average speedup of about 260x as compared to a serial CPU implementation. With the recently announced quad 8800 GPU cards, we estimate that our approach would attain a speedup of over 785x. The correctness of the Monte Carlo based SSTA implemented on a GPU has been verified by comparing its results with a CPU based implementation.
Using coalgebra and coinduction to define ontology-based multi-agent systems
Authors: Maja Hadzic, Elizabeth Chang
Venue: International Journal of Metadata, Semantics and Ontologies (2008)

In the past, algebra has been predominantly used to define computer systems. However, computer systems are becoming more dynamic nowadays and algebra is not suitable any more to define such systems. For this reason, coalgebra and coinduction have been introduced into the computer and information society. Coalgebra and coinduction present a powerful mechanism for representing many different kinds of dynamic systems using a common formal framework. We make use of coinductive reasoning to provide a framework and define a dynamic process within the ontology-based multi-agent system. The principle is illustrated on a system specially designed to intelligently retrieve human disease information.
An on-chip solution for static ADC test and measurement
Authors: Brendan Mullane, Ciaran MacNamee, Vincent O'Brien, Thomas Fleischmann
Venue: Proceedings of the 19th ACM Great Lakes symposium on VLSI (2009)

This paper presents a solution for implementing low-cost ADC BIST into a System-on-Chip design. The solution is based on generating a programmable ramp as a test signal into the ADC and measuring the linear parameters using the histogram based test. An original approach for accurately measuring the Hits-per-Code as the ramp traverses the ADC transfer curve is presented. In particular, it is shown that code transitions or code flicker noise have an impact on the overall accuracy. This test procedure permits a ramp generator implementation and test engine design that is predominantly a digital solution. Results demonstrate lower silicon area overheads and lower test time capability.
Design of Architectures for Proximity-aware Services: Experiments in Context-based Authentication with Subjective Logic
Authors: Gabriele Lenzini
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2009)

This paper addresses the design of architectures for proximity-aware services with unobtrusive and context-based identification and authentication features. A service is ''proximity-aware'' when it automatically detects the presence of entities in its proximity. A process of authentication is ''context-based'' when it uses contextual information to discern among different identities and to evaluate whether they are authentic or not. We refer to an existing architecture, available in our institute, where a network of sensors is used to detect the presence users and user devices in various locations in the building. Proximity-aware services are offered at intelligent coffee corners where users are unobtrusively identified and authenticated while approaching. A level of authentication for an approaching identity is calculated as the overall expectation of belief (i.e., trust) that the identity (and not another) is effectively standing at the coffee space. We use the Subjective Logic as a theoretic framework for belief calculations. According to a previous study of ours, we manage each sensors as it was a recommender giving subjective ''opinions'' over statements concerning the position of users. Informally, an identity has higher level of authentication in a certain place the more sensors-recommenders believe that that identity stands in that place. We present and comment the results from an array of experiments where we show how trust can be used to authenticate an identity in a room. We perform the experiments under different circumstances, namely we change the area of the room and the relative disposition of the sensors. We comment the results and we indicate some guidelines for a design that aims to maximise its benefits from our authentication framework.