ppxscal/embedding_network huggingface dataset:
Conservative volumetric visibility with occluder fusion
Authors: Gernot Schaufler, Julie Dorsey, Xavier Decoret, François X. Sillion
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

Visibility determination is a key requirement in a wide range of graphics algorithms. This paper introduces a new approach to the computation of volume visibility, the detection of occluded portions of space as seen from a given region. The method is conservative and classifies regions as occluded only when they are guaranteed to be invisible. It operates on a discrete representation of space and uses the opaque interior of objects as occluders. This choice of occluders facilitates their extension into adjacent opaque regions of space, in essence maximizing their size and impact. Our method efficiently detects and represents the regions of space hidden by such occluders. It is the first one to use the property that occluders can also be extended into empty space provided this space is itself occluded from the viewing volume. This proves extremely effective for computing the occlusion by a set of occluders, effectively realizing occluder fusion. An auxiliary data structure represents occlusion in the scene and can then be queried to answer volume visibility questions. We demonstrate the applicability to visibility preprocessing for real-time walkthroughs and to shadow-ray acceleration for extended light sources in ray tracing, with significant acceleration in both cases.
A Mixed Finite Element--Finite Volume Formulation of the Black-Oil Model
Authors: Luca Bergamaschi, Stefano Mantica, Gianmarco Manzini
Venue: SIAM Journal on Scientific Computing (1999)

In this paper a sequential coupling of mixed finite element and shock-capturing finite volume techniques is proposed, in order to numerically solve the system of partial differential equations arising from the Black-Oil model. The Brezzi--Douglas--Marini space of degree one (BDM1) is used to approximate the Darcy's velocity in the parabolic-type pressure equation, while the system of mass conservation laws is solved by a higher order Godunov-type scheme, here extended to triangle-based unstructured grids. Numerical results on 1-D and 2-D test cases prove the effectiveness and the robustness of the coupling, which seems particularly suited to handling high heterogeneities and at the same time accurately resolving steep gradients without spurious oscillations.
A Multicast Routing Algorithm Reducing Congestion
Authors: Anna G. H. Hać, Dongmei G. H. Wang
Venue: International Journal of Network Management (1997)

A new multicast routing algorithm reducing congestion is presented in this article. The algorithm uses efficient routing by transmitting multicast packets across fewer links in the network. In addition, the algorithm balances the use of network nodes and links by reducing packet duplication in the nodes. &copy; 1997 John Wiley Sons, Ltd.
k-Neighborhood-Covering and -Independence Problems for Chordal Graphs
Authors: Shiow-Fen Hwang, Gerard J. Chang
Venue: SIAM Journal on Discrete Mathematics (1998)

Suppose G=(V,E) is a simple graph and k is a fixed positive integer. A vertex z k-neighborhood-covers an edge (x,y) if d(z,x) \leq k$ and d(z,y) \leq k$. A k-neighborhood-covering set is a set C of vertices such that every edge in E is k-neighborhood-covered by some vertex in C. A k-neighborhood-independent set is a set of edges in which no two distinct edges can be k-neighborhood-covered by the same vertex in V. In this paper we first prove that the k-neighborhood-covering and the k-neighborhood-independence problems are NP-complete for chordal graphs. We then present a linear-time algorithm for finding a minimum k-neighborhood-covering set and a maximum k-neighborhood-independent set for a strongly chordal graph provided that a strong elimination ordering is given in advance.
Automatic inference of models for statistical code compression
Authors: Christopher W. Fraser
Venue: ACM SIGPLAN Notices (1999)

This paper describes experiments that apply machine learning to compress computer programs, formalizing and automating decisions about instruction encoding that have traditionally been made by humans in a more ad hoc manner. A program accepts a large training set of program material in a conventional compiler intermediate representation (IR) and automatically infers a decision tree that separates IR code into streams that compress much better than the undifferentiated whole. Driving a conventional arithmetic compressor with this model yields code 30% smaller than the previous record for IR code compression, and 24% smaller than an ambitious optimizing compiler feeding an ambitious general-purpose data compressor.
Turn Performance of Aircraft, Revisited
Authors: Judah Milgram
Venue: SIAM Review (1998)

This note clarifies some aspects of the airplane design airspeeds discussed in a recent note treating the minimum turning radius of an aircraft.
BISTing Datapaths under Heterogeneous Test Schemes
Authors: D. Berthelot, M. L. Flottes, B. Rouzeyre
Venue: Journal of Electronic Testing: Theory and Applications (1999)

In this paper, we present a fast and efficient algorithm for BISTing datapaths described at the Register Transfer (RT) level. This algorithm is parameterized by user defined tuning factors allowing tradeoffs between fault coverage, area overhead and test application time. This algorithm is generic in the sense it handle and mixes heterogeneous test pattern generators and compactors.
Face fixer: compressing polygon meshes with properties
Authors: Martin Isenburg, Jack Snoeyink
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

Most schemes to compress the topology of a surface mesh have been developed for the lowest common denominator: triangulated meshes. We propose a scheme that handles the topology of arbitrary polygon meshes. It encodes meshes directly in their polygonal representation and extends to capture face groupings in a natural way. Avoiding the triangulation step we reduce the storage costs for typical polygon models that have group structures and property data.
A licensing model for scholarly textbases
Authors: Julia Flanders, Elli Mylonas
Venue: Proceedings of the fifth ACM conference on Digital libraries (2000)

Smaller scholarly projects represent a sector of the digital library which makes an important contribution to research on specialized text encoding, retrieval, and interface design for scholarly audiences. Such projects, however, face funding and publication challenges which threaten their long-term survival. The Women Writers Project is using an unusual tier-based licensing model to make the transition from grant-funded research project to independent financial viability.
Indirect Obstacle Control Problem for Semilinear Elliptic Variational Inequalities
Authors: Qihong Chen
Venue: SIAM Journal on Control and Optimization (1999)

An optimal control problem for a coupled system of a semilinear elliptic equation and an obstacle variational inequality is considered. Existence and optimality conditions of optimal triple are established.
Modeling users in role-based access control
Authors: Sylvia Osborn, Yuxia Guo
Venue: Proceedings of the fifth ACM workshop on Role-based access control (2000)

The essential properties of a simple model for users, groups and group hierarchies for role-based access control, embodied in a group graph, are presented. The interaction between the group graph and the role graph model of Nyanchama and Osborn is shown. More complex models of users and their compatibility with the group graph model are discussed.
Universal DNA tag systems: a combinatorial design scheme
Authors: Amir Ben-Dor, Richard Karp, Benno Schwikowski, Zohar Yakhini
Venue: Proceedings of the fourth annual international conference on Computational molecular biology (2000)

Custom-designed DNA arrays offer the possibility of simultaneously monitoring thousands of hybridization reactions These arrays show great potential for many medical and scientific applications such as polymorphism analysis and genotyping. Relatively high costs are associated with the need to specifically design and synthesize problem specific arrays. Recently, an alternative approach was suggested that utilizes fixed, universal arrays. This approach presents an interesting design problem&mdash;the arrays should contain as many probes as possible, while minimizing experimental errors caused by cross-hybridization. We use a simple thermodynamic model to cast this design problem in a formal mathematical framework. Employing new combinatorial ideas, we derive an efficient construction for the design problem, and prove that our construction is near-optimal.
CMOS system-on-a-chip voltage scaling beyond 50nm
Authors: Azeez J. Bhavnagarwala, Blanca Austin, Ashok Kapoor, James D. Meindl
Venue: Proceedings of the 10th Great Lakes symposium on VLSI (2000)

The limits on CMOS energy dissipation imposed by subthreshold leakage currents and by wiring capacitance are investigated for CMOS generations beyond 50nm at NTRS projected local and global clock rates for high performance processors. Physical short-channel MOSFET models that consider high-field effects, threshold voltage roll-off and reverse subthreshold swing roll-off are employed in tandem with stochastic interconnect distributions to calculate optimal supply voltage, threshold voltage and gate sizes that minimize total CMOS power dissipation by exploiting trade-offs between saturation drive current and subthreshold leakage current and between device size and wiring capacitance. CMOS power dissipation at its lower limit, increases exponentially with clock frequency imposing limits on performance set by heat removal. Heat removal constraints at high local clock rates, limiting the average wire length and device size within a local zone of synchrony, or macrocell, in a short-wire cellular array architecture are used to project the maximum macrocell size and count for generations beyond 100nm.
A nested mutual authentication protocol
Authors: John A. Bull, David J. Otway
Venue: ACM SIGOPS Operating Systems Review (1999)

This paper describes an authentication protocol that is suited to modern, object-based, client-server systems. Each object in a chain, whether acting in a client or server role, handles authentication with its neighbours, without any need to be aware of the resultant global behaviour. Session keys are returned by an authentication server which services a client-server chain as a whole: nested requests are built along the forward chain; the final server presents the whole package to the authentication server; and sessions keys are delivered back down the chain. The protocol, as described, avoids entanglement with the politics of cryptography by using One-Way-Hash-Functions throughout. The authentication chain might traverse different legal jurisdictions, but adjacent applications can use returned session keys for any legitimate purpose, including message sealing or encryption.
Accelerating Pipelined Integer and Floating-Point Accumulations in Configurable Hardware with Delayed Addition Techniques
Authors: Zhen Luo, Margaret Martonosi
Venue: IEEE Transactions on Computers (2000)

The speed of arithmetic calculations in configurable hardware is limited by carry propagation, even with the dedicated hardware found in recent FPGAs. This paper proposes and evaluates an approach called delayed addition that reduces the carry-propagation bottleneck and improves the performance of arithmetic calculations. Our approach employs the idea used in Wallace trees to store the results in an intermediate form and delay addition until the end of a repeated calculation such as accumulation or dot-product; this effectively removes carry propagation overhead from the calculation's critical path. We present both integer and floating-point designs that use our technique. Our pipelined integer multiply-accumulate (MAC) design is based on a fairly traditional multiplier design, but with delayed addition as well. This design achieves a 72MHz clock rate on an XC4036xla-9 FPGA and 170MHz clock rate on an XV300epq240-8 FPGA. Next, we present a 32-bit floating-point accumulator based on delayed addition. Here, delayed addition requires a novel alignment technique that decouples the incoming operands from the accumulated result. A conservative version of this design achieves a 40 MHz clock rate on an XC4036xla-9 FPGA and 97MHz clock rate on an XV100epq240-8 FPGA. We also present a 32-bit floating-point accumulator design with compiler-managed overflow avoidance that achieves a 80MHz clock rate on an XC4036xla-9 FPGA and 150MHz clock rate on an XCV100epq240-8 FPGA.
WYSIWYT testing in the spreadsheet paradigm: an empirical evaluation
Authors: Karen J. Rothermel
Venue: Proceedings of the 22nd international conference on Software engineering (2000)

Is it possible to achieve some of the benefits of formal testing within the informal programming conventions of the spreadsheet paradigm? We have been working on an approach that attempts to do so via the development of a testing methodology for this paradigm. Our &ldquo;What You See Is What You Test&rdquo; (WYSIWYT) methodology supplements the convention by which spreadsheets provide automatic immediate visual feedback about values by providing automatic immediate visual feedback about &ldquo;testedness&rdquo;. In previous work we described this methodology; in this paper, we present empirical data about the methodology's effectiveness. Our results show that the use of the methodology was associated with significant improvement in testing effectiveness and efficiency even with no training on the theory of testing or test adequacy that the model implements. These results may be due at least in part to the fact that use of the methodology was associated with a significant reduction in overconfidence.
APPN &mdash; The Control Point
Authors: Jesper Nilausen
Venue: International Journal of Network Management (1996)

In this third article in the series on managing APPN networks we will go into more details about the APPN Control Point, which resides in every APPN Network and End Node, coordinating the exercising of all APPN Services, and being responsible for all local management functions.
The effect of mobile IP handoffs on the performance of TCP
Authors: Anne Fladenmuller, Ranil De Silva
Venue: Mobile Networks and Applications (1999)

Mobile IP is a standard for handling routing for hosts that have moved from their home network. This paper studies the costs of the Mobile IP handoff that occurs when a mobile host moves between networks. Experiments were carried out with Mobile IP and TCP over varying network conditions to observe the effect of handoffs on the transmission. This paper shows that although Mobile IP may be appropriate for current applications, its long handoff periods make it unsuitable for the future.
Operational Concepts of Nonmonotonic Logics Part 2: Autoepistemic Logic
Authors: Grigoris Antoniou, Volker Sperschneider
Venue: Artificial Intelligence Review (1998)

The subject of nonmonotonic reasoning is reasoning with incomplete information. One of the main approaches is autoepistemic logic in which reasoning is based on introspection. This paper aims at providing a smooth introduction to this logic, stressing its motivation and basic concepts. The meaning (semantics) of autoepistemic logic is given in terms of so-called expansions which are usually defined as solutions of a fixed-point equation. The present paper shows a more understandable, operational method for determining expansions. By improving applicability of the basic concepts to concrete examples, we hope to make a contribution to a wider usage of autoepistemic logic in practical applications.
Semantic integration of environmental models for application to global information systems and decision-making
Authors: D. Scott Mackay
Venue: ACM SIGMOD Record (1999)

Global information systems have the potential of providing decision makers with timely spatial information about earth systems. This information will come from diverse sources, including field monitoring, remotely sensed imagery, and environmental models. Of the three the latter has the greatest potential of providing regional and global scale information on the behavior of environmental systems, which may be vital for setting multi-governmental policy and for making decisions that are critical to quality of life. However, environmental models have limited prootocol for quality control and standardization. They tend to have weak or poorly defined semantics and so their output is often difficult to interpret outside a very limited range of applications for which they are designed. This paper considers this issue with respect to spatially distributed environmental models. A method of measuring the semantic proximity between components of large, integrated models is presented, along with an example illustrating its application. It is concluded that many of the issues associated with weak model semantics can be resolved with the addition of self-evaluating logic and context-based tools that present the semantic weaknesses to the end-user.
PLM: fast convergence for cumulative layered multicast transmisson schemes
Authors: A. Legout, E. W. Biersack
Venue: Proceedings of the 2000 ACM SIGMETRICS international conference on Measurement and modeling of computer systems (2000)

A major challenge in the Internet is to deliver live audio/video content with a good quality and to transfer files to large number of heterogeneous receivers. Multicast and cumulative layered transmission are two mechanisms of interest to accomplish this task efficiently. However, protocols using these mechanisms suffer from slow convergence time, lack of inter-protocol fairness or TCP-fairness, and loss induced by the join experiments.In this paper we define and investigate the properties of a new multicast congestion control protocol (called PLM) for audio/video and file transfer applications based on a cumulative layered multicast transmission. A fundamental contribution of this paper is the introduction and evaluation of a new and efficient technique based on packet pair to infer which layers to join. We evaluated PLM for a large variety of scenarios and show that it converges fast to the optimal link utilization, induces no loss to track the available bandwidth, has inter-protocol fairness and TCP-fairness, and scales with the number of receivers and the number of sessions. Moreover, all these properties hold in self similar and multifractal environment.
An Adjustable Description Quality Measure for Pattern Discovery Usingthe AQ Methodology
Authors: Kenneth A. Kaufman, Ryszard S. Michalski
Venue: Journal of Intelligent Information Systems (2000)

In concept learning and data mining tasks, the learner is typically faced with a choice of many possible hypotheses or patterns characterizing the input data. If one can assume that training data contain no noise, then the primary conditions a hypothesis must satisfy are consistency and completeness with regard to the data. In real-world applications, however, data are often noisy, and the insistence on the full completeness and consistency of the hypothesis is no longer valid. In such situations, the problem is to determine a hypothesis that represents the best trade-off between completeness and consistency. This paper presents an approach to this problem in which a learner seeks rules optimizing a rule quality criterion that combines the rule coverage (a measure of completeness) and training accuracy (a measure of inconsistency). These factors are combined into a single rule quality measure through a lexicographical evaluation functional (LEF). The method has been implemented in the AQ18 learning system for natural induction and pattern discovery, and compared with several other methods. Experiments have shown that the proposed method can be easily tailored to different problems and can simulate different rule learners by modifying the parameter of the rule quality criterion.
A Stable Numerical Method for Inverting Shape from Moments
Authors: Gene H. Golub, Peyman Milanfar, James Varah
Venue: SIAM Journal on Scientific Computing (1999)

We derive a stable technique, based upon matrix pencils, for the reconstruction of (or approximation by) polygonal shapes from moments. We point out that this problem can be considered the dual of 2-D numerical quadrature over polygonal domains. An analysis of the sensitivity of the problem is presented along with some numerical examples illustrating the relevant points. Finally, an application to the problem of gravimetry is explored where the shape of a gravitationally anomalous region is to be recovered from measurements of its exterior gravitational field.
Optimal All-to-All Personalized Exchange in Self-Routable Multistage Networks
Authors: Yuanyuan Yang, Jianchao Wang
Venue: IEEE Transactions on Parallel and Distributed Systems (2000)

All-to-all personalized exchange is one of the most dense collective communication patterns and occurs in many important applications in parallel computing. Previous all-to-all personalized exchange algorithms were mainly developed for hypercube and mesh/torus networks. Although the algorithms for a hypercube may achieve optimal time complexity, the network suffers from unbounded node degrees and thus has poor scalability in terms of I/O port limitation in a processor. On the other hand, a mesh/torus has a constant node degree and better scalability in this aspect, but the all-to-all personalized exchange algorithms have higher time complexity. In this paper, we propose an alternative approach to efficient all-to-all personalized exchange by considering another important type of networks, multistage networks, for parallel computing systems. We present a new all-to-all personalized exchange algorithm for a class of unique-path, self-routable multistage networks. We first develop a generic method for decomposing all-to-all personalized exchange patterns into some permutations which are realizable in these networks, and then present a new all-to-all personalized exchange algorithm based on this method. The newly proposed algorithm has $O(n)$ time complexity for an $n \times n$ network, which is optimal for all-to-all personalized exchange. By taking advantage of fast switch setting of self-routable switches and the property of a single input/output port per processor in a multistage network, we believe that a multistage network could be a better choice for implementing all-to-all personalized exchange due to its shorter communication latency and better scalability.
A signaling architecture for wireless ATM access networks
Authors: Nikos H. Loukas, Nikos I. Passas, Lazaros Merakos, Iakovos S. Venieris
Venue: Wireless Networks (2000)

A multiservice wireless Asynchronous Transfer Mode &lpar;ATM&rpar; access system is considered from a signaling protocol viewpoint. In an attempt to generalize and extend results and experiences obtained from the specification, design, and implementation of fixed ATM&dash;based access networks, we extend the concept of the broadband V interface &lpar;referred to as VB&rpar; for application to wireless ATM access networks. The proposed architecture follows the signaling structure of Broadband ISDN &lpar;B&dash;ISDN&rpar; User&ndash;Network Interface &lpar;UNI&rpar;, thus offering the possibility for integration of the wireless ATM access system into fixed B&dash;ISDN. It is shown that the use of the proposed access signaling architecture provides cost effective implementations without degrading the agreed Quality of Service &lpar;QoS&rpar;, and simplifies call/connection and handover control. The evaluation of the proposed access signaling protocol structure yields results that fall within acceptable ATM signaling performance measures. A performance comparison of our approach with an alternative access signaling configuration is also carried out to quantify the relative gains.