ppxscal/embedding_network huggingface dataset:
The propositional formula checker HeerHugo
Authors: Jan F Groote, Joost P. Warners
Venue:  (1999)

HeerHugo is a propositional formula checker that determines whether a given formula is satisfiable or not. Its main ingredient is the branch/merge rule, that is inspired by an algorithm proposed by St\a{a}llmarck, which is protected by a software patent. The algorithm can be interpreted as a breadth first search algorithm. HeerHugo differs substantially from St\a{a}llmarck''s algorithm, as it operates on formulas in conjunctive normal form and it is enhanced with many logical rules including unit resolution, 2--satisfiability tests and additional systematic reasoning techniques In this paper, the main elements of the algorithm are discussed, and its remarkable effectiveness is illustrated with some examples and computational results.
Inductive Definition in Type Theory
Authors: Paul F Mendler
Venue:  (1987)

Type theories can provide a foundational account of constructive mathematics, and for the computer scientist, they can also serve the dual roles of specification and programming languages. In the search for natural and expressive extensions to the NuPrl type theory, we are lead to consider forms of inductive and co-inductive definition. We realize these notions through the addition of two new type constructors, denoted $\mu and \nu$. This represents a step towards a more expressive theory, without adopting a completely impredicative notion of type. With these constructors we can define all the common inductive data types, from natural numbers to infinite trees. Through the propositions-as-types principle, these type constructors yield inductively defined propositions. The induction principle associated with the $\mu$ types lets us define well-founded recursive functions, and dual principle for the $\nu$ types lets us inductively define their ``infinite'''' elements. We present another induction principle for the $\mu$ types which takes advantage of the information hiding properties of the $\{ __ | __ \}$ type, and can be used to define an unbounded search operator, or more generally, to compute not with elements of the $\mu$ type, but under the assumption of its inhabitation. After presenting the proof rules for these new type constructors we give a semantic account, from which intuitionistic consistency is a consequence. First, we consider the the question of inductive types in the simpler setting of the second-order lambda calculus, where we prove a strong normalization property. We also consider typing terms in the presence of type constraints, and present a condition on the constraints (of polynomial complexity in the size of the constraints) for determining if the terms will be strongly normalizable or there will be a diverging typed term. Second, we develop a semantic account of the basic type theory, then relativize it to account for the impredicativity inherent in the definition of the new type constructors. We also show how this model can justify other impredicative type constructors, such as an impredicative type abstraction operation.
Supporting Hierarchy and Heterogeneous Interfaces in Multi-Hop Wireless Ad Hoc Networks
Authors: Josh Broch, David A. Maltz, David B. Johnson
Venue: Proceedings of the 1999 International Symposium on Parallel Architectures, Algorithms and Networks (1999)

Much progress has been made toward solving the problem of routing packets inside an ad hoc network, but there are presently no complete proposals for connecting ad hoc networks together to form larger networks, or for integrating them with wired internets. This paper describes a technique that allows a single ad hoc network to span across heterogeneous link layers. Using this technique, we can both integrate ad hoc networks into the hierarchical Internet and support the migration of mobile nodes from the Internet into and out of ad hoc networks via Mobile~IP. Taken together, these solutions improve the scalability of flat ad hoc networks by introducing hierarchy, and they enable all nodes participating in the ad hoc network to be reachable from anywhere in the world. We have implemented each of the solutions in a real testbed of 8 nodes using the Dynamic Source Routing (DSR) protocol. Generalizing our solutions, we describe several abstract scenarios and present our ideas for solving them.
Distributed Agreement in the Presence of Processor and Communication Faults
Authors: Kenneth J. Perry, Sam Toueg
Venue:  (1984)

A model of distributed computation is proposed in which processes may fail by not sending or receiving the messages specified by a protocol. The solution to the Byzantine Generals Problem for this model is presented. Our algorithm exhibits early-stopping under conditions of less than maximum failure and is as efficient as the algorithms developed for the more restrictive crash-fault model in terms of time, message, and bit complexity. We show extant models to under-estimate resiliency when faults in the communication medium are considered; the model of this paper is more accurate in this regard.
Bond-Stretch Isomers of Transition Metal Complexes. Do They Exist?
Authors: Jun Song, Michael B. Hall
Venue:  (1991)

The existence of bond-stretch isomers of transition metal complexes and the electronic mechanisms explaining these isomers were reexamined by ab initio calculations. For (LWOCl2)+ and (L=N,N'',N"-trimethyl-1,4,7-triazacyclononane) complexes, only the 2A'' state can be identified as the ground state. The orbital crossing mechanism cannot explain the occurrence of the two stable isomers. For cis-mer-MoOCl2(PR3)3 complexes, the second order Jahn-Teller effect is too small to cause the bond-stretch phenomenon. On both molecular systems, our calculations support the structure of the blue "isomer" as the stable compound and preclude the existence of any other isomer with a long M-O bond and similar energy.
Nonlinear and Hybrid Systems in Automotive Control
Authors: Rolf Johansson, Anders Rantzer
Venue:  (2002)

:This book should be of use to academic researchers and graduate students as well as to engineers in the automotive industry.
The Hopcroft-Tarjan Planarity Algorithm, Presentation and Improvements
Authors: David Gries, Jinyun Xue
Venue:  (1988)

We give a rigorous, yet, we hope, readable, presentation of the Hopcroft-Tarjan linear algorithm for testing the planarity of a graph, using more modern principles and techniques for developing and presenting algorithms that have been developed in the past 10-12 years (their algorithm appeared in the early 1970''s). Our algorithm not only tests planarity but also constructs a planar embedding, and in a fairly straightforward manner. The paper concludes with a short discussion of the advantages of our approach.
Incremental Reduction in the Lambda Calculus
Authors: John H. Field, Tim Teitelbaum
Venue:  (1990)

An incremental algorithm is one that takes advantage of the fact that the function it computes is to be evaluated repeatedly on inputs that differ only slightly from one another, avoiding duplication of common computations. We define here a new notion of incrementality for reduction in the untyped $\lambda$-calculus and describe an incremental reduction algorithm, $\Lambda^{inc}$. We show that $\Lambda^{inc}$ has the desirable property of performing non-overlapping reductions on related terms, yet is simple enough to allow a practical implementation. The algorithm is based on a novel $\lambda$-reduction strategy that may prove useful in a non-incremental setting as well. Incremental $\lambda$-reduction can be used to advantage in any setting where an algorithm is specified in a functional or applicative manner.
Compiler Optimizations for Parallel Sparse Programs with Array Intrinsics of Fortran 90
Authors: Rong-Guey Chang, Tyng-Ruey Chuang, Jenq-Kuen Lee
Venue: Proceedings of the 1999 International Conference on Parallel Processing (1999)

In our recent work, we have been working on providing parallel sparse supports for array intrinsics of Fortran 90. Our supporting library uses a two-level design. In the low-level routines, it requires the input sparse matrices to be specified with compression/distribution schemes for array functions. In the high-level representations, sparse array functions are overloaded with Fortran 90 array intrinsic interfaces so that programmers need not concern about low-level details. This raises a very interesting optimization problem in the strategies to transform high-level representations to low-level routines by automatic selections and supplies of distribution and compression schemes for sparse arrays.In this paper, we propose solutions to this optimization problem. The optimization problem is shown to be NP-hard. We develop a heuristic algorithm based on annotated program graphs, and the algorithm is shown to be practical. Experimental results on an IBM SP-2 show that the selection algorithms are effective in improving the performances of application programs that use sparse data sets.
Model-Based Clustering and Visualization of Navigation Patterns on a Web Site
Authors: Igor Cadez, David Heckerman, Christopher Meek, Padhraic Smyth, Steven White
Venue: Data Mining and Knowledge Discovery (2003)

We present a new methodology for exploring and analyzing navigation patterns on a web site. The patterns that can be analyzed consist of sequences of URL categories traversed by users. In our approach, we first partition site users into clusters such that users with similar navigation paths through the site are placed into the same cluster. Then, for each cluster, we display these paths for users within that cluster. The clustering approach we employ is model-based (as opposed to distance-based) and partitions users according to the order in which they request web pages. In particular, we cluster users by learning a mixture of first-order Markov models using the Expectation-Maximization algorithm. The runtime of our algorithm scales linearly with the number of clusters and with the size of the data&semi; and our implementation easily handles hundreds of thousands of user sessions in memory. In the paper, we describe the details of our method and a visualization tool based on it called WebCANVAS. We illustrate the use of our approach on user-traffic data from msnbc.com.
Inspired 3D Lighting and Compositing
Authors: David A. Parrish
Venue:  (2002)

:Learn to animate like the veterans of Hollywood's biggest films! Inspired 3D Lighting and Compositing takes you behind the scenes and guides you in creating believable computer graphics scenes. This brilliant four-color book gives a detailed explanation of how lighting and compositing works and then applies these concepts to real-world examples. Targeted at intermediate to advanced animators, this book will teach you professional tips and techniques for any 3D program you're using. You'll also enjoy this book if you're a curious moviegoer and want to discover what goes on behind the scenes with special effects. The companion Web site provides sample models, graphics, characters, and trial software. 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
Sum Amusements: A Case Study from the Analysis of Algorithms
Authors: Edmund A. Lamagna, Robert A. Ravenscroft,  Jr., Jeffrey S Vitter
Venue:  (1990)

While analyzing the average performance of an algorithm for a geometric problem, the summation $ \sum_{k=1}^{n} k ^ m / 2 ^ k $ was encountered. This sum is a particular case of the sum $ S_{m,n} = \sum_{k=1}^n ~ \alpha ^ k ~ k ^ m $ for $ 0 ~>~ \alpha ~>~ 1$. Solving $S_{m,n}$ requires a variety of techniques and is an interesting case study in the analysis of algorithms. This paper examines both the solution of this summation and the methods used to obtain the solution. Three approaches to solving $S_{m,n}$ are examined. It is found that $S_{m,n}$ is defined by \[ S_{m,n} ~=~ C_m ~-~ D_{m,n} \] where $C_m$ is a function of $\alpha$ and $m$ and $D_{m,n}$ is the product of $\alpha^ n$ with a polynomial in $n$ of degree $m$. Both functions are defined recursively. Several techniques used in the analysis of algorithm are applied to evaluate these recurrences. Induction is used to prove results obtained by examing small cases. Generating function methods are employed to derive expressions defining $C_m$ and $D_{m,n}$. Asymptotics are found for $C_m$, $D_{m,n}$, and $S_{m,n}$. Integration is used to find a good asymptotic expression for $C_m$. Complex analysis techniques are employed to find an asymptotic for $D_{m,n}$. Asymptotics for $S_{m,n}$ are found by studyinge sum in the region about the value of $k$ that maximizes $k^ m alpha^k$.
Getting to know mono
Authors: Julio David Quintana
Venue: Linux Journal (2003)

Working code shows how you can already work with objects created in one language, from another. 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
Hack Proofing Your Identity in the Information Age
Authors: Teri Bidwell, Ryan Russell, Michael Cross
Venue:  (2002)

:If youre like most people, your day includes writing checks or using a debit card at stores, using credit cards at the gas station, or using an ATM terminal to get cash. If youre among the growing numbers of Internet users, youve probably also bought a thing or two online, and might even do your banking or trade stocks online. If more than half of the following statements are true, you are at high risk for identity theft: You receive at least one loan solicitation or preapproved credit offer each week. You usually toss preapproved credit or loan solicitations in the trash without shredding. You usually toss old banking or credit documents in the trash without shredding. Mail is delivered to you in an unlocked mailbox. You send mail by placing it in an unlocked mailbox. You carry your Social Security or Social Insurance card in your wallet. Your Social Security Number is printed on the health insurance card in your wallet. Your Social Security Number is printed on your drivers license. Your Social Security or drivers license number is printed on your personal checks. You make occasional or frequent purchases online using a credit card. You seldom check whether a site is "secure" before using a credit card to make an online purchase or before disclosing private data, such as your Social Security Number, to a Web site. You seldom read Web site privacy policies before disclosing private information. Your online account with your bank, health insurer, or stockbroker uses your SSN as your account number. Your bank doesnt require a password before allowing you to make a withdrawal in person. The password for your online bank account is written down in an unlocked location. Your ATM PIN is written down in your wallet or on the ATM card. You sometimes share your name, address, e-mail address, and/or phone number with Web sites. You dont use privacy software to remove identifying information from your computer. You seldom take advantage of programs designed to opt-out of information sharing. You havent seen your credit report in the past year. Your Internet-connected computer stores private or financial information and is not protected from the Internet by both a firewall and antivirus software.
Case-Based Analysis for Virtual Model Application in AEC Industry
Venue: Proceedings of the 1999 International Conference on Information Visualisation (1999)

This paper introduces the efficient application of Virtual Reality (VR) technologies in the Architecture, Engineering and Construction (AEC) industry, where conventional plastic models are mainly used, which is called Physical Mock Up (PMU). An idea of Virtual Model (VM) is introduced in the paper.The VM consists of digital models added by digital information about the project, such as CAD drawings, digital maps of periphery, scanned aerial photos, on-site digital pictures and documents.The paper investigates three principal points as follows; (1) whether presentation of the VM is as efficient as the PMU in terms of its power of expression, (2) whether digital information of the VM is useful to discuss views, ideas and interests about the construction project, (3) whether the VM is practical enough to use in the AEC industry. Pilot trials of the VM in actual construction projects are illustrated in the paper. Those are an on-going land readjustment project in Osaka and a large-scale soil borrowing project in Wakayama, Japan.
Morphological Definition of Anatomic Shapes Using Minimal Datasets
Authors: Egor Zindy, David Burton
Venue: Proceedings of the International Conference on Information Visualisation (2000)

A new method for outlining tumor volumes and surrounding organs from computed tomography slices is presented here. This task is performed during radiotherapy treatment planning and usually consists of the hand drawing of a set of contours on the appropriate computed tomography slices of the patient lying in treatment position. This method is both time consuming and prone to errors. Our solution, base d on three-dimensional scattered data interpolation, fits a three-dimensional primitive object on the contours, which are considered as 3-dimensional scattered points. Adding points to the interpolated contours iteratively refines the precision of this fit. Interpolation using radial basis functions is combined with an appropriate mapping function between the primitive object and the scattered point cloud to provide this iterative warping. As a result, both a 3-Dimensional mesh object and a set of contours are output. In this paper, we describe the mapping function, as well as present some results obtained using this method.
Diseno de paginas Web Interactivas con JavaScript (Interactive Web Page Design with JavaScript), 2 edition
Authors: Juan Carlos Oros
Venue:  (2002)

:Este libro constituye la herramienta perfecta para realizar paginas Web interactivas, ya que se explican de manera clara y con multitud de ejemplos, las caracteristicas fundamentales de JavaScript para que el lector pueda aprender las bases de su programacion y anadir a sus propias paginas interactividad y multimedia. La segunda edicion de la obra se complementa con todas las novedades que la version JavaScript 1.3 aporta a los desarrolladores de paginas Web. Su contenido es de inestimable ayuda tanto para los usuarios que ya saben disenar paginas Web con HTML (disenadores, Webmasters, programadores, etc.), como para aquellos que nunca han creado un programa, ya que introduce de forma paulatina y sin esfuerzo el lenguaje JavaScript. Los primeros pasos consisten en afianzar unos conocimentos minimos de lenguaje HTML para que despues, poco a poco, el lector se vaya familiarizando con la terminologia de JavaScript hasta terminar con las Hojas de Estilo en Cascada, una de las ultimas innovaciones de Internet. La obra se complementa con un disquete que contiene infinidad de ejemplos con los que el usuario podra ver, entender, aprender y afianzar todas las explicaciones. En resumen: esta obra constituye una valiosa herramienta para todas aquellas personas que deseen aprender a programar paginas Web interactivas con JavaScript. 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
Axiomatic Verification to Enhance Software Reliability
Authors: Richard D. Schlichting
Venue:  (1982)

Techniques that facilitate the design of reliable software are described. Two distinct phenomena that can cause execution of a program to deviate from its specifications are considered. The first is the failure of the computing system on which the program is running. When this occurs, the system might not be capable of following the instructions specified by the program. The second phenomenon is that the program is written so that it will not execute consistently with its specifications, even on a failure-free computing system. A methodology is presented for designing programs that can cope with failures in the underlying system. It is based on the notion of a fail-stop processor a processor with well-defined failure mode operating characteristics. Axiomatic program verification techniques are extended for use in developing provably correct programs for such processors. The problem of meeting response time goals in light of failures is discussed. Lastly, the problem of implementing processors that, with high probability, behave like fail-stop processors is addressed. Programming logics have already been developed to reason about sequential programs, and parallel programs that use shared memory or synchronous message-passing. That work is extended to facilitate reasoning about programs that use asynchronous message-passing. Two benefits accrue from this. The obvious one is that partial correctness proofs can be written for concurrent programs that use such primitives. This allows such programs to be understood as predicate transformers, instead of by contemplating all possible execution interleavings often an intractible task. The other benefit is that these proof rules and their derivation shed light onto how this interference can be controlled. In particular, disciplines that make asynchronous message-passing primitives simple and safe to use are explored. A partial correctness proof of the two-phase commit protocol illustrates the application of the new techniques. This protocol, widely used in database applications, ensures that a specified action is performed either at all sites in a distributed system, or at no site, despite failures.
Greening of the internet
Authors: Maruti Gupta, Suresh Singh
Venue: Proceedings of the 2003 conference on Applications, technologies, architectures, and protocols for computer communications (2003)

In this paper we examine the somewhat controversial subject of energy consumption of networking devices in the Internet, motivated by data collected by the U.S. Department of Commerce. We discuss the impact on network protocols of saving energy by putting network interfaces and other router & switch components to sleep. Using sample packet traces, we first show that it is indeed reasonable to do this and then we discuss the changes that may need to be made to current Internet protocols to support a more aggressive strategy for sleeping. Since this is a position paper, we do not present results but rather suggest interesting directions for core networking research. The impact of saving energy is huge, particularly in the developing world where energy is a precious resource whose scarcity hinders widespread Internet deployment.
Receiver-oriented adaptive buffer allocation in credit-based flow control for ATM networks
Authors: H. T. Kung, Koling Chang
Venue: Proceedings of the Fourteenth Annual Joint Conference of the IEEE Computer and Communication Societies (Vol. 1)-Volume - Volume 1 (1995)

In credit-based flow control for ATM networks, a buffer is first allocated to each VC (virtual circuit) and then credit control is applied to the VC for avoiding possible buffer overflow. Receiver-oriented, adaptive buffer allocation allows a receiver to allocate its buffer dynamically, to VCs from multiple upstream nodes based on their bandwidth usage. The paper describes, in detail, such an adaptive algorithm capable of supporting a wide range of link speeds and propagation delays, and also packing multiple allocation and credit records in a single message. Analysis and simulation results show that even under highly bursty traffic, the adaptive scheme guarantees no cell loss due to congestion, and achieves excellent performance in utilization, fairness, ramp-up and packing, while requiring only relatively small node memory and bandwidth overhead. The required memory need only be 4*RTT+2*N, where RTT is the link round-trip time in cell cycles and N is the number of VCs.