ppxscal/embedding_network huggingface dataset:
Efficient Hierarchical Key Management Scheme for Access Control in the Mobile Agent
Authors: Yu-Fang Chung, Tzer-Shyong Chen, Chia-Hui Liu, Tzu-Chi Wang
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications - Workshops (2008)

Technologies and their applications related to e-commerce have always been the topic of interests to attract researchers and widely discussed. Among them, the use of the mobile agent in e-commerce is a highly potential technology which has accumulated a lot of interests in recent years. Since the mobile agent has high autonomy and mobility, it can move, unbridled, in different execution environments. At the same time, it can automatically detect its current environment and respond accordingly. Finally, it can also carry out work, or tasks assigned to it by its user. The above qualities make the mobile agent very suitable for use in e-commerce. The internet is an open environment. When there is a need to transfer, or exchange confidential information over the internet, the security of the present Internet environment must be improved. Even so, during its execution, a mobile agent needs to roam around the internet between different servers on the internet. At the same time, a mobile agent may also come in contact or interact with other mobile agents or hosts. Therefore, the users may worry that a mobile agent may not work properly if it meets with a malicious program, or if it is tampered with by a malicious host, or that confidential information carried by the mobile agent may be stolen by other agents. To ensure the safety of mobile agents on the internet, this paper proposes a security scheme suitable for use to mobile agents: The scheme includes access control and key management to ensure the security and confidentiality of information and the system. In view of the access control and key management scheme for mobile agents proposed by Volker and Mehrdad [1], this paper proposes a new scheme that uses the concepts of polynomial interpolation formula [19], the hierarchy structure and the superkey [8] to improve the previous security schemes which need a large amount of space for the mobile agent. According to this paper’s security and performance analysis, it is proved that the proposed scheme can efficiently protect the mobile agents.
Multicast Using Static Trees
Authors: Jiang Li, Moses Garuba, Legand Burge
Venue: Proceedings of the Fifth International Conference on Information Technology: New Generations (2008)

IP multicast has been known to have deployment difficulties. Among many contributing factors, the model per se is probably one of the most critical. Overlay multicast does not solve all the problems either. We therefore proposed a new multicast architecture named MUST, inspired by previous efforts. In essence, the architecture uses an overlay network to interconnect statically configured IP multicast trees to create the data paths for improvised multicast groups. While being incrementally deployed, it can evolve towards higher efficiency. In this paper, we described the model in detail, theoretically estimated its cost, and compared the cost with that of overlay multicast.
Tearing a strip off the plane
Authors: Bruce L. Bauslaugh
Venue: Journal of Graph Theory (1998)

In this article we examine some homomorphic properties of certain subgraphs of the unit-distance graph. We define Gr to be the subgraph of the unit-distance graph induced by the subset (-&infin;, &infin;) &times; [0, r] of the plane. The bulk of the article is devoted to examining the graphs Gr, when r is the minimum width such that Gr contains an odd cycle of given length. We determine for each odd n the minimum width rn such that $G_{r_{n}}$ contains an n-cycle Cn, and characterize the embeddings of Cn in $G_{r_{n}}$. We then show that $G_{r_{n}}$ is homomorphically equivalent to Cn when n &equiv; 3 (mod 4), but $G_{r_{n}}$ is a core when n &equiv; 1 (mod 4). We begin by showing that Gr is homomorphically compact for each r &ge; 0, as defined in [1]. We conclude with some other interesting results and open problems related to the graphs Gr. &copy; 1998 John Wiley & Sons, Inc. J. Graph Theory 29: 17&ndash;33, 1998
Extending Source Code Generators for Evidence-Based Software Certification
Authors: Ewen Denney, Bernd Fischer
Venue: Proceedings of the Second International Symposium on Leveraging Applications of Formal Methods, Verification and Validation (2006)

Automated code generation offers many advantages over manual software development but treating generators as trusted black boxes raise problems for certi?cation. Traditional process-oriented approaches to certi?cation thus require that the generator be veri?ed to the same level of assurance as the generated code, but this is infeasible for realistic generators. However, generators can be extended to support an evidence-based approach to certi?cation. By careful design of the trusted kernel, assurance of the generator itself is not required.In this paper, we describe several related extensions to two in-house code generators to provide two forms of evidence along with the code: safety proofs and safety explanations. We also describe how additionally provided links are used to trace between the code and the safety artifacts.
Learning to Drive a Real Car in 20 Minutes
Authors: Martin Riedmiller, Mike Montemerlo, Hendrik Dahlkamp
Venue: Proceedings of the 2007 Frontiers in the Convergence of Bioscience and Information Technologies (2007)

The paper describes our first experiments on Reinforcement Learning to steer a real robot car. The applied method, Neural Fitted Q Iteration (NFQ) is purely data-driven based on data directly collected from real-life experiments, i.e. no transition model and no simulation is used. The RL approach is based on learning a neural Q value function, which means that no prior selection of the structure of the control law is required. We demonstrate, that the controller is able to learn a steering task in less than 20 minutes directly on the real car. We consider this as an important step towards the competitive application of neural Q function based RL methods in real-life environments.
The inverse of an automorphism in polynomial time
Authors: M. Dickerson
Venue: Proceedings of the 30th Annual Symposium on Foundations of Computer Science (1989)

The first known polynomial-time algorithm for computing the inverse of a K-algebra automorphism is presented. The algorithm works over a commutative ring K and is based on a polynomial decomposition algorithm. A polynomial-time algorithm for computing the left composition factor of a multivariate decomposition is also presented. Two related open problems are stated.
Design of Software Architecture for Smart Meeting Space
Authors: Namgon Kim, Sangwoo Han, JongWon Kim
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

This paper introduces the software design for smartmeeting space (SMeet) that enables users to collaboratewith remote persons by using a wide range of devices em-bedded in networked meeting rooms. To enhance the qual-ity of user experience in remote collaboration, SMeet is de-signed to satisfy several considerations from the integratedview of media, networking, display, and interaction ser-vices. We propose a software architecture of SMeet to flex-ibly associate component services to support high-qualitymedia transport, high-resolution tiled display, and displayinteraction. We also present an approach to create compos-ite services by combining component services. We explainkey issues to dynamically build composite services and tointegrate the service composition scheme with the proposedsoftware architecture.
Mixed altruistic and selfish users in wireless mesh networks: a game theoretic model for multihop bandwidth sharing
Authors: Shih-Lung Chao, Guan-Yu Lin, Hung-Yu Wei
Venue: Proceedings of the 9th ACM international symposium on Mobile ad hoc networking and computing (2008)

Mesh networking is a feasible and effective way to route between nodes. The reliability and versatility of wireless mesh networks makes it a critical part of the future Wireless Internet. We apply a tree routing structure to formulate the multihop relay system topology. Wireless mesh network has a gateway node that connects to wired-line Internet. There are several kinds of node characteristics in the system, either being selfish or altruistic. We model bandwidth sharing and multihop relaying problem in wireless mesh networks with Nash Equilibrium. The novelty of this work is in modeling mixed selfish and altruistic user behaviors in multihop relay networks. In addition, the bandwidth sharing strategy space in our fixed pricing network access model differs from the previous variable pricing network model.
Collaborative clustering with the use of Fuzzy C-Means and its quantification
Authors: Witold Pedrycz, Partab Rai
Venue: Fuzzy Sets and Systems (2008)

In this study, we introduce the concept of collaborative fuzzy clustering-a conceptual and algorithmic machinery for the collective discovery of a common structure (relationships) within a finite family of data residing at individual data sites. There are two fundamental features of the proposed optimization environment. First, given existing constraints which prevent individual sites from exchanging detailed numeric data, any communication has to be realized at the level of information granules. The specificity of these granules impacts the effectiveness of ensuing collaborative activities. Second, the fuzzy clustering realized at the level of the individual data site has to constructively consider the findings communicated by other sites and act upon them while running the optimization confined to the particular data site. Adhering to these two general guidelines, we develop a comprehensive optimization scheme and discuss its two-phase character in which the communication phase of the granular findings intertwines with the local optimization being realized at the level of the individual site and exploits the evidence collected from other sites. The proposed augmented form of the objective function is essential in the navigation of the overall optimization that has to be completed on a basis of the data and available information granules. The intensity of collaboration is optimized by choosing a suitable tradeoff between the two components of the objective function. The objective function based clustering used here concerns the well-known Fuzzy C-Means (FCM) algorithm. Experimental studies presented include some synthetic data, selected data sets coming from the machine learning repository and the weather data coming from Environment Canada.
On impulse responses and representations of multidimensional linear systems
Authors: Irwin W. Sandberg
Venue: Proceedings of the 4th WSEAS International Conference on Systems Theory and Scientific Computation (2004)

An expression is given for the most general input-output map associated with the members of a certain important large family of multidimensional linear systems. This expression is a uniform limit of a convolution. Also given is a necessary and sufficient condition under which the limit can be written as a convolution, and we relate this to the concepts of an impulse response and a q-response limit, and to the flawed concept of the Dirac impulse function.
Hybrid evolutionary algorithm for solving optimization problems
Authors: Kangshun Li, Wei Li
Venue: International Journal of Computer Mathematics (2007)

A fast and efficient hybrid evolutionary algorithm (HEA) for solving constrained optimization problems is presented. The algorithm is based on the rules of the (1+μ) evolutionary algorithm, particle transportation theory, the principle of energy minimization, and the law of increasing entropy of particle systems. The rules for evolution and the fitness function for constrained optimization problems are defined using transportation theory. In the algorithm, energy minimization and increasing entropy gradually drive the particle systems in the phase space from non-equilibrium into equilibrium during the evolutionary process, so that individual particles are able to cross over and mutate during the program run and hence the process of finding the optimal solution process is accelerated. Numerical experiments demonstrate that the solutions of the constrained optimization problems found using the algorithm are very accurate and that convergence is fast. Our algorithm is able to find the global solutions of constrained optimization problems more efficiently than traditional evolutionary algorithms, and also avoids the occurrence of premature phenomena during the solution process.
Independent Unbiased Coin Flips From A Correlated Biased Source: A Finite State Markov Chain
Authors: M. Blum
Venue: Proceedings of the 25th Annual Symposium onFoundations of Computer Science, 1984 (1984)

von Neumann's trick for generating an absolutely unbiased coin from a biased one is this: 1. Toss the biased coin twice, getting 00, 01, 10, or 11. 2. If 00 or 11 occur, go back to step 1; else 3. Call 10 a H, 01 a T. Since p[H] = p[1]*p[0] = p[T], the output is unbiased. Example: 00 10 11 01 01 /spl I.oarr/ H T T. Peter Elias gives an algorithm to generate an independent unbiased sequence of Hs and Ts that nearly achieves the Entropy of the one-coin source. His algorithm is excellent, but certain difficulties arise in trying to use it (or the original von Neumann scheme) to generate bits in expected linear time from a Markov chain. In this paper, we return to the original one-coin von Neumann scheme, and show how to extend it to generate an independent unbiased sequence of Hs and Ts from any Markov chain in expected linear time. We give a right and wrong way to do this. Two algorithms A and B use the simple von Neumann trick on every state of the Markov chain. They differ in the time they choose to announce the coin flip. This timing is crucial.
Resource Efficient TCP: Reducing Contention-Induced Spurious Timeouts in QoS -Aware MANETs
Authors: Consolee Mbarushimana, Ali Shahrabi
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

The bandwidth is one of the most precious resources in Mobile Ad Hoc Networks (MANETs); their network protocols should therefore be able to achieve an increase in efficiency of bandwidth utilization. TCP, which implements flow control to regulate the network traffic, plays a significant role in determining the workload of the network. However, spurious TCP retransmissions can increase the link utilization and consequently limiting the amount of spare bandwidth available as extensively reported in the literature. This problem is exacerbated by the presence of high priority traffic and traffic differentiation introduced in IEEE 802.11e. In this paper, we focus on the optimization of TCP for resource efficiency, by limiting the number of contention-induced retransmissions. Using feedback from the MAC layer, the TCP layer can be notified of the medium contention state and adjusts its retransmission timer accordingly. Our simulation results demonstrate the effectiveness of our proposal in various scenarios. Our proposal achieves a gain of 15% in resource utilization and reduces power consumption by retransmitting fewer segments; it also improves TCP performance in terms of goodput and end-to-end delay.
Bi-criteria Scheduling of Scientific Workflows for the Grid
Authors: Marek Wieczorek, Stefan Podlipnig, Radu Prodan, Thomas Fahringer
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

The drift towards new challenges in Grid computing, including the Utility Grid paradigm and Service Level Agreements based on quality-of-service guarantees, implies the need for new, robust, multi-criteria scheduling algorithms that can be applied by the user in an intuitive way. Multiple scheduling criteria addressed by the related Grid research include execution time, the cost of running a task on a machine, reliability, and different data quality metrics. The existing bi-criteria scheduling approaches are usually dedicated for certain criterion pairs only that require the user to define one's preferences either as weights assigned to the criteria or as fixed constraints defined for one of the criteria. These requirements are often not feasible for the user and not suited to the specificity of the multi-criteria scheduling problem. We propose a novel requirement specification method based on a sliding constraint, and we model the problem as an extension of the multiple-choice knapsack problem. We propose a general bi-criteria scheduling heuristic called Dynamic Constraint Algorithm (DCA) based on dynamic programming, dedicated to the problem model defined by us. In the experimental study, we show that in most of the problem variants, DCA outperforms two existing algorithms designed for the same problem. It also shows relatively low scheduling times for workflows of medium size.
Functional genetic programming and exhaustive program search with combinator expressions
Authors: Forrest Briggs, Melissa O'Neill
Venue: International Journal of Knowledge-based and Intelligent Engineering Systems (2008)

Using a strongly typed functional programming language for genetic programming has many advantages, but evolving functional programs with variables requires complex genetic operators with special cases to avoid creating ill-formed programs. We introduce combinator expressions as an alternative program representation for genetic programming, providing the same expressive power as strongly typed functional programs, but in a simpler format that avoids variables and other syntactic clutter. We outline a complete genetic-programming system based on combinator expressions, including a novel generalized genetic operator, and also show how it is possible to exhaustively enumerate all well-typed combinator expressions up to a given size. Our experimental evidence shows that combinator expressions compare favorably with prior representations for functional genetic programming and also offers insight into situations where exhaustive enumeration outperforms genetic programming and vice versa.
Characterizing post-fire vegetation recovery of California chaparral using TM/ETM+ time-series data
Authors: A. Hope, C. Tague, R. Clark
Venue: International Journal of Remote Sensing (2007)

A time series of normalized difference vegetation index (NDVI) data derived from 11 TM/ETM+ images was used to examine the recovery characteristics of chaparral vegetation in a small watershed near Santa Barbara, California following a fire event in 1985. The NDVI recovery trajectory was compared to a generalized recovery trajectory of leaf area index (LAI) for the same region, which was established using a chronosequence approach and TM/ETM+ data. Post-fire NDVI recovery trajectories were derived for the entire catchment and for individual vegetation types. Post-fire NDVI spatial patterns on each image date were compared to the pre-fire pattern to determine the extent to which the pre-fire pattern was re-established, and the rate of this recovery. Results indicated that the post-fire recovery trajectory for the catchment area average NDVI was similar to the previously established regional LAI trajectory based on a chronosequence approach. The NDVI recovery was disrupted by drought stress and attained pre-fire levels approximately 10 years after the fire. Individual vegetation types did not exhibit different rates of recovery and the recovery trajectories were only distinguished by the maximum post-fire NDVI observed after 10 years. The post-fire NDVI spatial pattern also showed a systematic return to pre-fire conditions, but exhibited a more substantial disruption due to drought stress than was the case for the average NDVI recovery trajectory.
Packet concatenation at the IP level for performance enhancement in wireless local area networks
Authors: Dzmitry Kliazovich, Fabrizio Granelli
Venue: Wireless Networks (2008)

Wireless local area networks experience performance degradation in presence of small packets. The main reason for that is the large overhead added at the physical and link layers. This paper proposes a concatenation algorithm which groups IP layer packets prior to transmission, called PAC-IP. As a result, the overhead added at the physical and the link layers is shared among the grouped packets. Along with performance improvement, PAC-IP enables packet-based fairness in medium access as well as includes QoS support module handling delay-sensitive traffic demands. The performance of the proposed algorithm is evaluated through both simulations and an experimental WLAN testbed environment covering the single-hop and the widespread infrastructure network scenarios. Obtained results underline significant performance enhancement in different operating scenarios and channel conditions.
Improved parallel polynomial division and its extensions
Authors: D. Bini
Venue: Proceedings of the 33rd Annual Symposium on Foundations of Computer Science (1992)

The authors compute the first N coefficients of the reciprocal r(x) of a given polynomial p(x), (r(x)p(x)=1 mod x/sup N/, p(0) not=0), by using, under the PRAM arithmetic models, O(h log N) time-steps and O((N/h)(1+2/sup -h/log/sup (h)/ N)) processors, for any h, h=1,2, . . .,log/sup */ N, provided that O(logm) steps and m processors suffice to perform DFT on m points and that log/sup (0)/ N=N, log/sup (h)/ N=log/sub 2/log/sup (h-1)/N, h=1, . . .,log/sup */N, log/sup */N=max(h:log/sup (h)/N>0). The same complexity estimates apply to some other computations, such as the division with a remainder of two polynomials of degrees O(N) and the inversion of an N*N triangular Toeplitz matrix. They also show how to extend the techniques to parallel implementation of other recursive processes, such as the evaluation modulo x/sup N/ of the m-th root, p(x)/sup 1/m/, of p(x) (for any fixed natural m), for which we need O(log N log log N) time-steps and O(N/log log N) processors. The paper demonstrates some new techniques of supereffective slowdown of parallel algebraic computations, which they combine with a technique of stream contraction.
Modification of the method of integration along characteristics as adaptive mesh approach in solution of hyperbolic and parabolic PDEs
Authors: Suren Khachatryan
Venue: Proceedings of the 4th WSEAS International Conference on Systems Theory and Scientific Computation (2004)

Modification of the numeric integration method of hyperbolic and parabolic systems of partial differential equations is proposed. The method incorporates mesh adaptation and provides a straightforward strategy in recognition and treatment of most critical regions, such as discontinuities and shock fronts, in the integration domain. Results of the application to a spatially 1D system are discussed and the extension over multiple dimensions is described.
A periodic FMM for Maxwell's equations in 3D and its applications to problems related to photonic crystals
Authors: Yoshihiro Otani, Naoshi Nishimura
Venue: Journal of Computational Physics (2008)

This paper presents an FMM (Fast Multipole Method) for periodic boundary value problems for Maxwell's equations in 3D. The effect of periodicity is taken into account with the help of the periodised moment to local expansion (M2L) transformation formula, which includes lattice sums. We verify the proposed method by comparing the obtained numerical results with analytic solutions for models of the multi-layered dielectric slab. We then apply the proposed method to scattering problems for periodic two-dimensional arrays of dielectric spheres and compare the obtained energy transmittances with those from the previous studies. We also consider scattering problems for woodpile crystals, where we find a passband related to a localised mode. Through these numerical tests we conclude that the proposed method is efficient and accurate.