ppxscal/embedding_network huggingface dataset:
The Conserved Penrose-Fife Phase Field Model with Special Heat Flux Laws and Memory Effects
Authors: Elisabetta Rocca
Venue:  (2001)

In this paper a phase-field model of Penrose-Fife type is considered for diffusive phse transitions with conserved order parameter. Different motivations lead to investigate the case when the heat flux is the superposition of two different contributions; one part is the gradient of a function of the absolute temperature theta, behaving like 1/theta, as theta approaches to 0 and like -theta as theta tends to +infinity while the other is given by the Gurtin Pipkin law introduced in the theory of materials with thermal memory. An existence result for a related initial-boundary value problem is proven. Strengthening some assumptions on the data, the uniqueness of the solution is also achieved. 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
An agent-based architecture for distributed interfaces and timed media in a storytelling application
Authors: Jun Hu, Loe Feijs
Venue: Proceedings of the second international joint conference on Autonomous agents and multiagent systems (2003)

This paper presents an agent-based architecture that enables the presentation of interactive timed media to distributed and networked devices. The architecture provides an automatic mapping of the same document to different environments. It uses a hierarchy of PAC (Presentation-Abstraction-Control) agents, which allows separating the presentation aspects from the control aspects and dynamically registering the new PAC agents to the system.
An Efficient Scheme for Dynamic Data Replication
Authors: Swarup Acharya, Stanley B. Zdonik
Venue:  (1993)

This paper presents an efficient scheme for dynamic replication of data in distributed environments. The aim of the scheme is to increase system performance by intelligent data placement so as to optimize the message traffic in the network. Research in the recent past has comparatively focussed very little on using replication for increasing performance but has instead been directed more at improving system availability through replication. However, with the advent of mobile or nomadic computing, research in replication needs to change direction-- the underlying assumption of high speed networks no longer hold true. Wireless networks not only have lower bandwidth but are also very expensive to use. In such an environment, it is imperative that data be distributed intelligently to achieve a good system performance in terms of message costs and turnaround time. Besides, with mobility introduced in the system, earlier static schemes for improving performance (e.g., the File Allocation Problem) are no longer applicable. As a first step, we propose a totally distributed dynamic replication scheme, which uses a finite automaton based technique to learn access patterns. This accrued information is then used to predict future access sequences and dynamically reorder-- replicate or delete copies of data in the network, in anticipation of predicted accesses, to reduce network message costs. Being distributed, each node of the network bases its decision to replicate or delete an existing copy solely on local information. Our algorithm is also integrated and corrects some of the drawbacks of earlier theoretical work in this area. Finally, we present some preliminary simulation results which show that our scheme is very promising.
Creating Graphical Languages in Garden
Authors: Steven P. Reiss, Scott Meyers
Venue:  (1989)

Garden is an environment for conceptual programming. Conceptual programming means that programmers can create, view, and manipulate systems directly in terms of their conceptualizations of the systems. Such conceptualizations are frequently graphical in nature, and one of Garden''s greatest strengths is the ease with which it allows programmers to define graphical languages. In this paper we provide a step-by-step construction of a graphical FSA language. The language can be created in a matter of minutes, and does not require any use of the keyboard.
Surface approximation and Geometric Partitions
Authors: K P Agarwal, Subhash Suri
Venue:  (1994)

Motivated by applications in computer graphics, visualization, and scientific computation, we study the computational complexity of the following problem: Given a set $S$ of $n$ points sampled from a bivariate function $f(x,y)$ and an input parameter $\epsilon < 0$, compute a piecewise linear function $\Sigma(x,y)$ of minimum complexity (that is, a $xy$-monotone polyhedral surface, with a minimum number of vertices, edges, or faces) such that \[| \Sigma(x_p, y_p) \; - \; z_p | \:\:\leq\:\: \epsilon ,\quad \mbox{ for all } (x_p, y_p, z_p) \in S. \] We prove that the decision version of this problem is NP-Hard. The main result of our paper is a polynomial-time approximation algorithm that computes a piecewise linear surface of size $O(K_o \log K_o )$, where $K_o$ is the complexity of an optimal surface satisfying the constraints of the problem. The technique developed in our paper is more general and applies to several other problems that deal with partitioning of points (or other objects) subject to certain geometric %{\em disjointness\/} constraints. For instance, we get the same approximation bound for the following problem arising in machine learning: given $n$ `red'' and $m$ `blue'' points in the plane, find a minimum number of {\em pairwise disjoint\/} triangles such that each blue point is covered by some triangle and no red point lies in any of the triangles.
Effective Delay Control for High Rate Heterogeneous Real-time Flows
Authors: Weijia Jia, Hanxing Wang, Maoning Tang, Wei Zhao
Venue: Proceedings of the 23rd International Conference on Distributed Computing Systems (2003)

This paper presents a new method to control the delayperformance for high rate heterogeneous real-time trafficflows based on a novel traffic control algorithm which is ageneralization of traditional (\sigma, p) regulator. Our new controlalgorithm operates like the traditional regulator under thenormal loading situation, but provides more regulation forthe high rate (heavy load condition) of the traffic. For a setof heterogenous real-time traffic flows R, we can show thatDr(R) \le D(R) where Dr(R) and D(R) are the worst-casedelay bounds with our new control algorithm and that with(\sigma, p) regulator, respectively. More specifically, we developa set of formula that can be used to set the parameters inour new traffic controller so that the worst case delay boundis minimized by streaming the traffic flow. We can provethat there exists a minimum (average) input rate p* suchthat Dr(R) = D(R) for p \le p* and Dr(R) p*. Using the extended regulator can effectivelycontrol the delay when the average heterogeneous traffic rateis high. The issues are particularly useful for IntegratedServices where a flow may over claim its share of resourceand for Differentiated Services where a class of traffic flowsmay posses very high rates.
Future Challenges in VLSI Design
Authors: José A. B. Fortes
Venue: Proceedings of the IEEE Computer Society Annual Symposium on VLSI (ISVLSI'03) (2003)

In the current and coming decades VLSI design - whichcurrently enables us to build million-transistor chips - willbecome Gigascale (GSI) design and Terascale ScaleIntegration (TSI) design, respectively. In this context,''gigascale'' and ''terascale'' signifies more than onebillion and one trillion devices per chip, respectively.From a system design perspective, this increase inintegration levels is qualitatively different from pastintegration improvements of similar magnitudes. Inparticular, manufacturing defects will increase, deviceswill get less reliable, interconnect will be orders ofmagnitude slower than transistors, new nanotechnologieswill emerge, and signal and power management issueswill be aggravated. It is plausible that newnanotechnologies will be used to complement or replaceCMOS. This paper (and its presentation) discusses someof the unique system design challenges posed byanticipated nanoscale CMOS and molecular electronicstechnologies, and presents some ground-breakingsuggestions of novel system-level approaches to deal withthese challenges.
A Paradigm for Concurrency Control Protocols for Distributed Databases
Authors: Amr El Abbadi
Venue:  (1987)

In this thesis, we present a paradigm for concurrency control protocols for distributed replicated databases. This paradigm presents a framework for both developing and analyzing concurrency control protocols, especially those that are designed to handle partitioning failures. Any concurrency control protocol that is an instance of the paradigm must be correct. We show that several known protocols are instances of this paradigm. Consequently, these seemingly unrelated protocols can now be compared and their understanding is simplified. We also present two new concurrency control protocols: the virtual partitions protocol and the accessibility thresholds protocol. Both protocols allow the reading and writing of data in spite of site and communication failures, even when these failures lead to network partitioning. In neither protocol is it ever necessary for a read operation to physically access more than one copy, which makes these protocols desirable for applications where efficient read operations are necessary. The accessibility thresholds protocol provides the database designer with much flexibility in trading off the cost of executing operations and the availability of data objects. Unlike previous protocols, the cost of executing operations on an object is separated from the read and write availability of that object.
Developing Efficient Interpreters Based on Formal Language Specifications
Authors: Arnd Poetzsch-Heffter
Venue:  (1993)

The paper reports on extensions to the MAX system enabling the generation and refinement of interpreters based on formal language specifications. In these specifications, static semantics is defined by an attribution mechanism that allows to enrich syntax trees by control flow graphs. The dynamic semantics is defined by evolving algebras, a framework that has been successfully used to specify realistic programming languages. We apply the combined framework to a non-trivial example language and show how the resulting language specification can be refined in order to improve the efficiency of the generated interpreters. The framework provides enough modularity and flexibility so that such refinements can be carried out by local changes. We explain the implementation of the extensions to MAX and discuss applications of the system.
A software re-engineering method using domain models
Authors: J.-M. DeBaud, S. Rugaber
Venue: Proceedings of the International Conference on Software Maintenance (1995)

Current software reengineering technology is typically based on program analysis methods such as parsing and data flow analysis. This is inadequate for two reasons. First, such methods inherently fail to capture the context or purpose of the program. Second, the results of the program comprehension are not directly usable in program evolution. We introduce a method that addresses both of these problems. We use a domain model to understand the context of a program and an object oriented framework to record that understanding. The main step of this method consists of the construction of an executable domain model whose scope covers a family of target programs. A program is then reverse engineered using the domain model both as a guide and as a recording medium. In the last step, developers reengineer the target artifact using its abstract domain driven representation. We present a thorough example to illustrate this approach. Issues raised by the confluence of domain analysis and representation, reverse engineering, and artifact evolution are discussed. Implications on future work in the area are suggested.
Investigations in Geometric Subdivisions: Linear Shattering and Cartographic Map Coloring
Authors: Robert Freimer
Venue:  (2000)

< We consider three computational geometry problems: shattering, coloring < cartographic maps and Bruce''s suntan lotion problem. < < A subdivision ${\cal S}\subseteq\Re^d$ {\em shatters} a set of $n$ < objects if each object is contained within the closure of its own cell < of ${\cal S}$. We consider the problem of shattering polyhedra with < $N$ total vertices using an arrangement of hyperplanes. We show that < finding a minimum shattering of points in $\Re^2$ is \NP-Complete. A < restricted version using axes-parallel hyperplanes is also < \NP-Complete. The actual number of shattering hyperplanes required < varies between $O(n^{1/d})$ and $n-1$. We present algorithms that < produce locally optimal solutions with at most $n-1$ shattering < hyperplanes. For $\Re^2$, we achieve $O(n^2\log{n}+N^2)$ time < complexity. We have implemented a simplified version. For < $\Re^d,d\ge3$, we have an $O(N^d(n+\log{N}))$ time algorithm. We give < an $O(N^4)$ time approximation algorithm which guarantees a solution < within a factor of $1+\ln{n}$ of optimal for $\Re^2$. Detecting < whether a set of line segments is shatterable is shown to be < \3SUM-Hard. < < We consider cartographic map coloring for use in Geographical < Information Systems. The published proofs of the famous four-color < theorem yield impractical polynomial-time algorithms. Instead, we < implemented Thomassen''s linear-time five-coloring algorithm. Political < maps often require generalizations to the standard four-coloring < problem. We allow each country to have $m$ disjoint pieces, which is < Heawood''s $m$-pire problem. We also count node adjacency between < countries; such adjacency graphs are known as map graphs. If $k$ < regions meet at a point, we conjecture for $k\ge5$ that < $\lfloor\frac{3}{2}k\rfloor$ colors suffice. By combining $m$-pires with < node adjacency and islands, we can model actual GIS instances. We < implemented Br{\''e}laz''s $Dsatur$ heuristic, since no specific algorithm < exists for coloring our resulting {\em cartographic graphs}. < < Given convex polygon \P, let \D1, \D2\ be disks centered on \P''s < boundary with radii $r_1$ and $r_2$, chosen so that < $\P\subseteq\D1\cup\D2$ and $r_1+r_2$ is minimized. Bruce''s Suntan < Lotion problem asks for the disks'' locations and sizes. We describe the < optimal cover for a triangle when $r_2=0$ and generalize the solution to < convex polygons; the minimum covering disk can be found in linear time. < We show the best one-disk solution is always optimal; no superior < two-disk solution exits. <
On a Class of Concatenated (2 log2N-1)-Stage Interconnection Networks
Venue: Proceedings of the 1996 International Symposium on Parallel Architectures, Algorithms and Networks (1996)

Most static scheduling algorithms that schedule parallel programs represented by directed acyclic graphs (DAGs) are sequential. Parallelization, of scheduling algorithms is a new research area. This paper discusses the essential issues of parallel static scheduling and presents an efficient parallel scheduling algorithm, the HPMCP a1gorith.m. The proposed algorithm has been implemented on an Intel Paragon machine. It produces high-quality scheduling and is much faster than existing sequential and parallel algorithms. static scheduling and presents an efficient parallel scheduling algorithm, the HPMCP a1gorith.m. The proposed algorithm has been implemented on an Intel Paragon machine. It produces high-quality scheduling and is much faster than existing sequential and parallel algorithms. 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
Dining Philosophers that Tolerate Malicious Crashes
Authors: Mikhail Nesterenko, Anish Arora
Venue: Proceedings of the 22 nd International Conference on Distributed Computing Systems (ICDCS'02) (2002)

We present a solution to the problem of dining philosophers. Our solution tolerates malicious crashes. In a malicious crash the faile d process behaves arbitrarily for a finite time and then ceases all operation undetectably to other processes. The tolerance of our solution is achieved by the combination of stabilization and crash failure locality. Stabilization allows our program to recover from an arbitrary state. Crash failure locality ensures that only a limited number of processes are affected by a process crash. The crash failure locality of our solution is optimal.Finally,we argue that the malicious crash fault model and its extensions are worthy of further study as they admit tolerances that are not achieved under stronger fault models and are unnecessary under weaker fault models.
Model-Checking Algorithms for Continuous-Time Markov Chains
Authors: Christel Baier Boudewijn Haverkort, Holger Hermanns Joost-Pieter Katoen
Venue: IEEE Transactions on Software Engineering (2003)

Continuous-time Markov chains (CTMCs) have been widely used to determine system performance and dependability characteristics. Their analysis most often concerns the computation of steady-state and transient-state probabilities. This paper introduces a branching temporal logic for expressing real-time probabilistic properties on CTMCs and presents approximate model checking algorithms for this logic. The logic, an extension of the continuous stochastic logic CSL of Aziz et al., contains a time-bounded until operator to express probabilistic timing properties over paths as well as an operator to express steady-state probabilities. We show that the model checking problem for this logic reduces to a system of linear equations (for unbounded until and the steady-state operator) and a Volterra integral equation system (for time-bounded until). We then show that the problem of model-checking time-bounded until properties can be reduced to the problem of computing transient state probabilities for CTMCs. This allows the verification of probabilistic timing properties by efficient techniques for transient analysis for CTMCs such as uniformization. Finally, we show that a variant of lumping equivalence (bisimulation), a well-known notion for aggregating CTMCs, preserves the validity of all formulas in the logic.
A Fully Qualified Analog Design Flow for Non Volatile Memories Technologies
Authors: C. Roma
Venue: Proceedings of the 2nd International Symposium on Quality Electronic Design (2001)

The wide range and rapid increase in the complexity of CAD tools demand proven and safe design flows. This paper presents a fully validated methodology integrated as analog design flow to design non volatile memories. Specifically, it has been applied to designs in 0.35um EEPROM and 0.13um Flash Memory processes developed in our company. The remarkable feature of the proposed methodology is the excellent integration between CAD tools released by different vendors and internally developed solutions. Furthermore, we show a flow which provides full compatibility and flexibility among analog design steps that could cut down time-to-design, time-to-market and streamline the design quality, thus enhancing the circuit yield and robustness.
Locks and Full Disclosure
Authors: Bruce Schneier
Venue: IEEE Security and Privacy (2003)

The full disclosure versus bug secrecy debate is a lot larger than computer security. Matt Blaze's article on master-key locking systems in this issue (page 24) is a case in point. It turns out that the ways we've learned to conceptualize security and attacks in the computer world are directly applicable to other areas of security like door locks. But the most interesting part of this story is that the locksmith community went ballistic after Blaze published his research on master-key lock vulnerability. 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
Direction and Scope of Comprehension-Related Activities by Procedural and Object-Oriented Programmers: An Empirical Study
Authors: Cynthia L. Corritore, Susan Wiedenbeck
Venue: Proceedings of the 8th International Workshop on Program Comprehension (2000)

This study examines the direction and scope of comprehension-related activities of professional programmers carrying out several comprehension and maintenance activities over time. Procedural and object-oriented (OO) programmers studied a program and subsequently performed modifications during two sessions. Results showed that the OO programmers tended to use a strongly top-down approach to program understanding during an early phase of study of the program but increasingly used a bottom-up approach during the maintenance tasks. The procedural programmers used a more bottom-up orientation throughout all activities. The scope of the activities was greater for the procedural than for the OO programmers. However, regardless of paradigm, the programmers over time built a broad, rather than a localized, view of the program.
Improving Usefulness of Software Quality Classification Models Based on Boolean Discriminant Functions
Authors: Taghi M. Khoshgoftaar
Venue: Proceedings of the 13th International Symposium on Software Reliability Engineering (2002)

The cost-effectiveness of software reliability control endeavors can be increased if a software quality estimation was available prior to system tests and operations.If all likely fault-prone (fp) modules were identified prior to operations, then enhanced software reliability can be obtained.Boolean Discriminant Functions (BDFs) have been applied in the past as quality classification models.Simplicity and ease in model interpretation, make BDFs an attractive technique for software quality estimation.Software quality classification models based on BDFs, provide stringent rules for classifying not fault prone modules (nfp), thereby predicting a large number of modules as fp.Such models are practically not useful from software quality assurance and software management points of view.This is because, given the large number of modules predicted as fp, project management will face a difficult task of deploying, cost-effectively, the always-limited reliability improvement resources to all the fp modules.This paper proposes the use of "Generalized Boolean Discriminant Functions" (GBDFs) as a solution for improving the practical and managerial usefulness of classification models based on BDFs.In addition, the use of GBDFs avoids the need to build complex hybrid classification models in order to improve usefulness of models based on BDFs.A case study of a full-scale industrial software system is presented to illustrate the promising results obtained from using the proposed classification technique using GBDFs.
Implicit Point Location in Arrangements of Line Segments with an Application to Motion Planning
Authors: K P Agarwal, van M Kreveld
Venue:  (1992)

Let $\cal S$ be a set of $n$ (possibly intersecting) line segments in the plane. We show that the arrangement of $\cal S$ can be stored implicitly into a data structure of size $O(n\log^2n)$ so that the following query can be answered in time $O(n^{1/2}\log^2n)$: Given two query points, determine whether they lie in the same face of the arrangement of $\cal S$ and, if so, return a path between them that lies within the face. This version of the {\em implicit point location} problem is motivated by the following motion planning problem: given a polygonal robot $R$ with $m$ vertices and a planar region bounded by polygonal obstacles with $n$ vertices in total, preprocess them into a data structure so that, given initial and final positions of $R$, one can quickly determine whether there exists a continuous collision-free translational motion of $R$ from the initial to the final position. We show that such a query can be answered in time $O((mn)^{1/2} \, \log^2 \, mn)$ using $O(mn \, \log^2 mn)$ storage.