ppxscal/embedding_network huggingface dataset:
Hungary's Electronic Signature Act: Enhancing economic development with Secure Electronic Commerce transactions
Authors: Stephen E. Blythe
Venue: Information and Communications Technology Law (2007)

Hungary's Electronic Signature Act (ESA) became effective in 2001 and provides for legal recognition of electronic signatures (e-signatures) and electronic documents. Electronic documents and e-signatures are presumed to be admissible evidence in court and may not be challenged successfully based on the mere fact of their electronic form. An electronic document signed with an e-signature is deemed to be in compliance with a statutory requirement for a handwritten signature on a paper document. However, the ESA excludes family-related documents (e.g., marriage certificates and divorce decrees), and those documents must continue to be in paper form to have legal validity. Also, consumers are not obligated to accept the electronic form; if a consumer objects, a business firm must use paper documents. Hungarian government departments may elect to issue or accept electronic documents. Although all types of e-signatures are recognized, the digital signature enjoys most-favored status because it utilizes cryptographic methods resulting in a heightened degree of reliability and security. The ESA provides for the licensure of certification authorities (CAs). In order to get a CA license, an applicant applies to the Hungarian Communications Inspector (Authority) and must meet financial and knowledge requirements and not have a prior criminal record. The principal duties of CAs are to issue certificates to successful applicants and confirm the authenticity and integrity of e-signatures (and the electronic documents to which they are attached) to relying third parties. Before issuance of the certificate, the CA must confirm the identity of the applicant and ensure that all information received on the application is accurate. The CA is responsible for maintaining the security of all information that it receives from the applicant. For a CA to issue a 'qualified' certificate it must comply with higher security standards; the only type of e-signature that can meet these standards is the digital signature. When a qualified certificate is issued, the subscriber will be given the private key that will enable them to 'sign' electronic documents. CAs must maintain a publicly accessible repository of certificates and public keys that can be used to decrypt a subscriber's message. A CA may incur legal liability for publishing a certificate with inaccurate information or for issuing a private key that does not have an interactive relationship with its public key. The ESA provides for legal recognition of certificates issued by CAs in foreign countries if the foreign CA meets one of the five criteria.
Graphic Design Concepts..Plus!, First edition
Authors: Marvin Jacobs
Venue:  (2007)

Graphic design concepts for graphic design students and desktop publishers. It is a college textbook and a graphic design course for business desktop publishers. The book covers graphic design for business documents, business forms design, and website design.
Synthesising verified access control systems through model checking
Authors: Nan Zhang, Mark Ryan, Dimitar P. Guelev
Venue: Journal of Computer Security (2008)

We present a framework for evaluating and generating access control policies. The framework contains a modelling formalism called RW, which is supported by a model checking tool. RW is designed for modelling access control policies, and verifying their properties. The RW language is very expressive, allowing us to model complex access conditions which can depend on data values, other permissions, and agent roles. A property expresses the capability of a coalition of agents to achieve a goal, which may include reading and overwriting certain information. Given a model built based on a policy and a property, the model-checking algorithm decides whether the goal defined by the property is achievable by the coalition within the permissions the policy provides. In the case that the goal is achievable, the algorithm outputs strategies which may be used by the coalition to achieve the goal. The unachievability of legitimate goals may suggest that the policy does not provide the users enough permissions to carry out their actions. The achievability of malicious goals may reveal certain security holes in the policy. When malicious goals are achievable, the resulting strategies help to provide clues on amending the policy. The tool implements the algorithm and thus performs the RW model-checking. It can also convert a policy written in the RW language into a policy file in XACML. An access control system can then be built on the converted policy file.
Location Determination Using Radio Frequency RSSI and Deterministic Algorithm
Authors: A. Malekpour, T. C. Ling, W. C. Lim
Venue: Proceedings of the Communication Networks and Services Research Conference (2008)

In recent years, the employment of IEEE 802.11 radio signals for location determination in an indoor environment has drawn great attention. The basis of this technique is that the location of an object is estimated using an estimation algorithm and the radio frequency (RF) fingerprint database as a reference. The main target of this paper is to find an optimum strategy for the construction of the RF map and a decent estimation algorithm. By obtaining statistical data from several signal strength measurements, we investigate and identify three influential factors on the RSSI behavior. With this knowledge, we propose improvement to the existing deterministic algorithm. An algorithm for detection of and dealing with the aliasing problem is also suggested. Test results show that our proposed combinational deterministic method and the anti aliasing technique improves the system performance by up to 33% compared to other deterministic method using single scalar values.
CC(X): Semantic Combination of Congruence Closure with Solvable Theories
Authors: Sylvain Conchon, Evelyne Contejean, Johannes Kanig, Stéphane Lescuyer
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

We present a generic congruence closure algorithm for deciding ground formulas in the combination of the theory of equality with uninterpreted symbols and an arbitrary built-in solvable theory X. Our algorithm CC(X) is reminiscent of Shostak combination: it maintains a union-find data-structure modulo X from which maximal information about implied equalities can be directly used for congruence closure. CC(X) diverges from Shostak's approach by the use of semantic values for class representatives instead of canonized terms. Using semantic values truly reflects the actual implementation of the decision procedure for X. It also enforces to entirely rebuild the algorithm since global canonization, which is at the heart of Shostak combination, is no longer feasible with semantic values. CC(X) has been implemented in Ocaml and is at the core of Ergo, a new automated theorem prover dedicated to program verification.
More output-sensitive geometric algorithms
Authors: K. L. Clarkson
Venue: Proceedings of the 35th Annual Symposium on Foundations of Computer Science (1994)

A simple idea for speeding up the computation of extrema of a partially ordered set turns out to have a number of interesting applications in geometric algorithms; the resulting algorithms generally replace an appearance of the input size n in the running time by an output size A/spl les/n. In particular, the A coordinate-wise minima of a set of n points in R/sup d/ can be found by an algorithm needing O(nA) time. Given n points uniformly distributed in the unit square, the algorithm needs n+O(n/sup 5/8/) point comparisons on average. Given a set of n points in R/sup d/, another algorithm can find its A extreme points in O(nA) time. Thinning for nearest-neighbor classification can be done in time O(n log n)/spl Sigma//sub i/ A/sub i/n/sub i/, finding the A/sub i/ irredundant points among n/sub i/ points for each class i, where n=/spl Sigma//sub i/ n/sub i/ is the total number of input points. This sharpens a more obvious O(n/sup 3/) algorithm, which is also given here. Another algorithm is given that needs O(n) space to compute the convex hull of n points in O(nA) time. Finally, a new randomized algorithm finds the convex hull of n points in O(n log A) expected time, under the condition that a random subset of the points of size r has expected hull complexity O(r). All but the last of these algorithms has polynomial dependence on the dimension d, except possibly for linear programming.
Efficient path protection in bi-directional WDM systems
Authors: Ji Li, Kwan L. Yeung, Chun-Kit Chan
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2008)

Bi-directional WDM transmission is a technique that allows data to be transmitted simultaneously in both directions of a fiber, with different sets of wavelength channels for each direction. Compared with unidirectional WDM systems, it not only saves the cost of deploying extra fibers, but also allows more flexible bandwidth provisioning. To exploit this flexibility, we investigate path protection schemes for bi-directional WDM transmission systems in this paper. With path protection, a call is accepted if and only if an active data path together with a disjointed backup path can be found in the network. With bi-directional WDM, backup resource sharing in both directions of a fiber is possible. Based on a set of judiciously designed link cost functions, two original path protection schemes are proposed in this paper, BiPro and BiProLP. BiProLP aims at further economizing the hardware cost incurred by BiPro. In contrast to the traditional unidirectional schemes, we show that both BiPro and BiProLP can yield noticeably lower call blocking probability, higher system capacity and shorter active/backup path length.
Models, simulations, instantiations, and evidence: the case of digital evolution
Authors: Robert T. Pennock
Venue: Journal of Experimental Theoretical Artificial Intelligence (2007)

What is the difference between a simulation of X and simply another instance of X? Is there a point at which the "virtual reality" of a model becomes the real thing? This paper examines these questions using cases taken from recent developments in evolutionary engineering and artificial life research. By implementing the Darwinian mechanism and setting it to work on a design problem, scientists and engineers find that evolution not only can improve prior designs, but also produce novel technological solutions. Artificial life systems Tierra and Avida which operate at a higher level of abstraction than evolutionary engineering applications. I analyze simulation as a rational concept "S simulates R" and argue that it always includes some relevant property P, of R, that is captured but that there is always also some other that it omits, and that pragmatic factors fix what counts as relevant. The border between a simulation and an instance or R can change depending upon the context. I show that in one sense, evo-technology and artificial life simulate organic evolution, but in another relevant sense they are instances of evolution itself. Biologists can use such systems to experimentally test evolutionary hypotheses such as those involving the evolution of complex features and altruism. This analysis suggests lines for future research on broader questions about models classification and confirmation.
Gridcole: A tailorable grid service based system that supports scripted collaborative learning
Authors: Miguel L. Bote-Lorenzo, Eduardo Gómez-Sánchez, Guillermo Vega-Gorgojo, Yannis A. Dimitriadis, Juan I. Asensio-Pérez, Iván M. Jorrín-Abellán
Venue: Computers Education (2008)

This paper introduces Gridcole, a new system that can be easily tailored by educators in order to support the realization of scripted collaborative learning situations. To do so, educators can provide a script specifying the sequence of activities to be performed by learners as well as the tools and documents required to support them. Gridcole can then search for these tools in a service-oriented grid in order to integrate them so that they are available for users during the realization of the situation. Significantly, Gridcole has two features that are not supported by other tailorable systems. First, it allows the integration of tools that use supercomputing capabilities or specific hardware resources, thus enabling the possibility of supporting many situations in which this type of tools is required. Besides, Gridcole can guide learners during the realization of collaborative learning situations according to the sequences of activities specified in the scripts. This way, learners can benefit from the advantages of scripted collaborative learning. Gridcole has been evaluated using three collaborative learning situations conceived for real courses at university level. The results of the evaluation show that Gridcole does provide the desired properties concerning tool integration and activity guidance as well as that the proposed system can provide adequate support for a wide range of collaborative learning situations.
Pervasive Compiler Verification -- From Verified Programs to Verified Systems
Authors: Dirk Leinenbach, Elena Petrova
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

We report in this paper on the formal verification of a simple compiler for the C-like programming language C0. The compiler correctness proof meets the special requirements of pervasive system verification and allows to transfer correctness properties from the C0 layer to the assembler and hardware layers. The compiler verification is split into two parts: the correctness of the compiling specification (which can be translated to executable ML code via Isabelle's code generator) and the correctness of a C0 implementation of this specification. We also sketch a method to solve the boot strap problem, i.e., how to obtain a trustworthy binary of the C0 compiler from its C0 implementation. Ultimately, this allows to prove pervasively the correctness of compiled C0 programs in the real system.
Blue matter: scaling of N-body simulations to one atom per node
Authors: B. G. Fitch, A. Rayshubskiy, M. Eleftheriou, T. J. C. Ward, M. E. Giampapa, M. C. Pitman, J. W. Pitera, W. C. Swope, R. S. Germain
Venue: IBM Journal of Research and Development (2008)

N-body simulations present some of the most interesting challenges in the area of massively parallel computing, especially when the object is to improve the time to solution for a fixed-size problem. The Blue Matter molecular simulation framework was developed specifically to address these challenges, to explore programming models for massively parallel machine architectures in a concrete context, and to support the scientific goals of the IBM Blue Gene® Project. This paper reviews the key issues involved in achieving ultrastrong scaling of methodologically correct biomolecular simulations, particularly the treatment of the long-range electrostatic forces present in simulations of proteins in water and membranes. Blue Matter computes these forces using the particle-particle particle-mesh Ewald (P3ME) method, which breaks the problem up into two pieces, one that requires the use of three-dimensional fast Fourier transforms with global data dependencies and another that involves computing interactions between pairs of particles within a cutoff distance. We summarize our exploration of the parallel decompositions used to compute these finite-ranged interactions, describe some of the implementation details involved in these decompositions, and present the evolution of strong-scaling performance achieved over the course of this exploration, along with evidence for the quality of simulation achieved.
Superlinear convergence of the control reduced interior point method for PDE constrained optimization
Authors: Anton Schiela, Martin Weiser
Venue: Computational Optimization and Applications (2008)

A thorough convergence analysis of the Control Reduced Interior Point Method in function space is performed. This recently proposed method is a primal interior point pathfollowing scheme with the special feature that the control variable is eliminated from the optimality system. Apart from global linear convergence we show that this method converges locally superlinearly, if the optimal solution satisfies a certain non-degeneracy condition. In numerical experiments we observe that a prototype implementation of our method behaves as predicted by our theoretical results.
Talking the talk vs. walking the walk: salience of information needs in querying vs. browsing
Authors: Mikhail Bilenko, Ryen W. White, Matthew Richardson, G. Craig Murray
Venue: Proceedings of the 31st annual international ACM SIGIR conference on Research and development in information retrieval (2008)

Traditional information retrieval models assume that users express their information needs via text queries (i.e., their "talk"). In this poster, we consider Web browsing behavior outside of interactions with retrieval systems (i.e., users' "walk") as an alternative source of signal describing users' information needs, and compare it to the query-expressed information needs on a large dataset. Our findings demonstrate that information needs expressed in different behavior modalities are largely non-overlapping, and that past behavior in each modality is the most accurate predictor of future behavior in that modality. Results also show that browsing data provides a stronger source of signal than search queries due to its greater volume, which explains previous work that has found implicit behavioral data to be a valuable source of information for user modeling and personalization.
HCH for checking containment of XPath fragment
Authors: Jian-Hua Feng, Yu-Guo Liao, Yong Zhang
Venue: Journal of Computer Science and Technology (2007)

XPath is ubiquitous in XML applications for navigating XML trees and selecting a set of element nodes. In XPath query processing, one of the most important issues is how to efficiently check containment relationship between two XPath expressions. To get out of the intricacy and complexity caused by numerous XPath features, we investigate this issue on a frequently used fragment of XPath expressions that consists of node tests, the child axis (/), the descendant axis (//), branches ([]) and label wildcards (*). Prior work has shown that homomorphism technology can be used for containment checking. However, homomorphism is the sufficient but not necessary condition for containment. For special classes of this fragment, the homomorphism algorithm returns false negatives. To address this problem, this paper proposes two containment techniques, conditioned homomorphism and hidden conditioned homomorphism, and then presents sound algorithms for checking containment. Experimental results confirm the practicability and efficiency of the proposed algorithms.
Double precision geometry: a general technique for calculating line and segment intersections using rounded arithmetic
Authors: V. Milenkovic
Venue: Proceedings of the 30th Annual Symposium on Foundations of Computer Science (1989)

For the first time it is shown how to reduce the cost of performing specific geometric constructions by using rounded arithmetic instead of exact arithmetic. By exploiting a property of floating-point arithmetic called monotonicity, a technique called double-precision geometry can replace exact arithmetic with rounded arithmetic in any efficient algorithm for computing the set of intersections of a set of lines or line segments. The technique reduces the complexity of any such line or segment arrangement algorithm by a constant factor. In addition, double-precision geometry reduces by a factor of N the complexity of rendering segment arrangements on a 2/sup N/*2/sup N/ integer grid such that output segments have grid points as endpoints.
Faster path indexes for search in XML data
Authors: Nils Grimsmo
Venue: Proceedings of the nineteenth conference on Australasian database - Volume 75 (2008)

This article describes how to implement efficient memory resident path indexes for semi-structured data. Two techniques are introduced, and they are shown to be significantly faster than previous methods when facing path queries using the descendant axis and wild-cards. The first is conceptually simple and combines inverted lists, selectivity estimation, hit expansion and brute force search. The second uses suffix trees with additional statistics and multiple entry points into the query. The entry points are partially evaluated in an order based on estimated cost until one of them is complete. Many path index implementations are tested, using paths generated both from statistical models and DTDs.
Modeling of IP-GMPLS Multimedia Traffic and Network for Admission Control Using ns-2
Authors: Norashidah Md Din, Norsheila Fisal
Venue: Proceedings of the 2008 Second Asia International Conference on Modelling & Simulation (AMS) (2008)

We present our work on modeling multimedia traffic over an Internet Protocol – Generalised Multiprotocol Label Switching (IP-GMPLS) network for admission control using the network simulator ns-2. GMPLS networks are potential solutions to an all optical internet environment. To generate GMPLS network scenarios the MPLS components in the ns-2 was utilized. The multimedia traffic comprised of real time voice, real time video and best effort internet traffic. The network was validated using queuing theory and the blocking probability of the network was used as the performance evaluation parameter.
On the latency for information dissemination in mobile wireless networks
Authors: Zhenning Kong, Edmund M. Yeh
Venue: Proceedings of the 9th ACM international symposium on Mobile ad hoc networking and computing (2008)

In wireless networks, node mobility may be exploited to assist in information dissemination over time. We analyze the latency for information dissemination in large-scale mobile wireless networks. To study this problem, we map a network of mobile nodes to a network of stationary nodes with dynamic links. We then use results from percolation theory to show that under a constrained i.i.d. mobility model, the scaling behavior of the latency falls into two regimes. When the network is not percolated (subcritical), the latency scales linearly with the initial Euclidean distance between the sender and the receiver; when the network is percolated (supercritical), the latency scales sub-linearly with the distance.