ppxscal/embedding_network huggingface dataset:
Optimal policy for label switched path setup in MPLS Networks
Authors: T. Anjali, C. Scoglio, J. C. de Oliveira, I. F. Akyildiz, G. Uhl
Venue: Computer Networks: The International Journal of Computer and Telecommunications Networking (2002)

An important aspect in designing a multiprotocol label switching (MPLS) network is to determine an initial topology and to adapt it to the traffic load. A topology change in an MPLS network occurs when a new label switched path (LSP) is created between two nodes. The LSP creation involves determining the route of the LSP and the according resource allocation to the path. A fully connected MPLS network can be used to minimize the signaling. The objective of this paper is to determine when an LSP should be created and how often it should be re-dimensioned. An optimal policy to determine and adapt the MPLS network topology based on the traffic load is presented. The problem is formulated as a continuous time Markov decision process with the objective to minimize the costs involving bandwidth, switching, and signaling. These costs represent the trade-off between utilization of network resources and signaling/processing load incurred on the network. The policy performs a filtering control to avoid oscillations which may occur due to highly variable traffic. The new policy has been evaluated by simulation and numerical results show its effectiveness and the according performance improvement. A sub-optimal policy is also presented which is less computationally intensive and complicated.
Executable Object Modeling with Statecharts
Authors: David Harel, Eran Gery
Venue: Computer (1997)

Most object-oriented methods use a graphical notation, and most also adopt a state-based formalism to specify behavior. But most also fail to rigorously define the semantics of the languages they use to describe behavior. Without rigorous semantics, OO models can never be precise enough to produce fully executable models and enable automatic code synthesis. These issues are complicated and go beyond recommending a modeling approach or methodology-they are language design concerns, requiring rigorous mathematical underpinnings. Both syntax and semantics must be fully worked out: Any possible combination of constructs must be clearly characterized as syntactically legal or illegal, and each legal combination must be given a unique and formal meaning.In this article, the authors describe their integrated set of diagrammatic languages for object modeling built around statecharts and their supporting tool, Rhapsody, which produces a fully executable model and allows automatic code synthesis. As a result of the authors' collaboration with the team that defined the Unified Modeling Language, this language set and Rhapsody are consistent with UML.
Topological Considerations for the Diagnosability Conditions of Analogue Circuits Using a Pair of Conjugate Trees
Authors: Luis Hernández-Martínez, Arturo Sarmiento-Reyes
Venue: Journal of Electronic Testing: Theory and Applications (2003)

The idea of using topological conditions in the analysis of nonlinear circuits has attracted the attention of researchers in recent years. This paper introduces a method that foccusses on the problem of analogue circuit diagnosis. The method determines the topological conditions for assessing the diagnosability of analogue circuits by resorting to the pair of conjugate trees. The method deals with circuits containing V&ndash;resistors, I&ndash;resistors, independent current and voltage sources, nullators and norators. More active elements can also be included by using appropriate models based on nullator and norator schemes.
Efficient summarization of spatiotemporal events
Authors: Peggy Agouris, Anthony Stefanidis
Venue: Communications of the ACM (2003)

Raster datasets at discrete temporal instances capture a variety of spatiotemporal phenomena. These phenomena and the respective datasets that capture them may span various spatial and temporal scales, like a car's trajectory as it is captured by various cameras at video rates, or the long-term erosion of a river's edge captured by an annual series of aerial imagery.
Early Jump-Out Corner Detectors
Authors: J. Cooper, S. Venkatesh, L. Kitchen
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1993)

The authors present two new corner detectors. One works by using dissimilarity, along the contour direction to detect curves in the image contour, and the other estimates image curvature along the contour direction. These operators are fast, robust to noise, and require no subjective thresholding.
Current budgets for user services
Authors: Frances Bardello Craig
Venue: Proceedings of the 7th annual ACM SIGUCCS conference on User services (1979)

User Services organizations differ from one installation to another. These differences cover the scope of the responsibilities, the names of the organizations, the number of staff performing user services activities, salaries of the user services staff members, and budgets supporting the organizations. Although, there are indeed many differences, there are many common elements among user services organizations.A survey to identify the characteristics of user services organizations will be conducted. This talk will focus on the results of the survey. The initial sample of twenty or thirty universities will provide sufficient data for a more extensive survey. 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
On Lower Bounds for the Redundancy of Optimal Codes
Authors: Roberto De Prisco, Alfredo De Santis
Venue: Designs, Codes and Cryptography (1998)

The problem of providing bounds on the redundancy of an optimal code for a discrete memoryless source in terms of the probability distribution of the source, has been extensively studied in the literature. The attention has mainly focused on binary codes for the case when the most or the least likely source letter probabilities are known. In this paper we analyze the relationships among tight lower bounds on the redundancy r. Let r &ge; &phis;_D,i(x) be the tight lower bound on r for D-ary codes in terms of the value x of the i-th most likely source letter probability. We prove that &phis;_D,i-1(x) &le; &phis;_D,i(x) for all possible x and i. As a consequence, we can bound the redundancy when only the value of a probability (but not its rank) is known. Another consequence is a shorter and simpler proof of a known bound. We also provide some other properties of tight lower bounds. Finally, we determine an achievable lower bound on r in terms of the least likely source letter probability for D &ge; 3, generalizing the known bound for the case D = 2.
A Highly Effective Partition Selection Policy for Object Database Garbage Collection
Authors: Jonathan E. Cook, Alexander L. Wolf, Benjamin G. Zorn
Venue: IEEE Transactions on Knowledge and Data Engineering (1998)

We investigate methods to improve the performance of algorithms for automatic storage reclamation of object databases. These algorithms are based on a technique called partitioned garbage collection, in which a subset of the entire database is collected independently of the rest. We evaluate how different application, database system, and garbage collection implementation parameters affect the performance of garbage collection in object database systems. We focus specifically on investigating the policy that is used to select which partition in the database should be collected. Three of the policies that we investigate are based on the intuition that the values of overwritten pointers provide good hints about where to find garbage. A fourth policy investigated chooses the partition with the greatest presence in the I/O buffer. Using simulations based on a synthetic database, we show that one of our policies requires less I/O to collect more garbage than any existing implementable policy. Furthermore, that policy performs close to a locally optimal policy over a wide range of simulation parameters, including database size, collection rate, and database connectivity. We also show what impact these simulation parameters have on application performance and investigate the expected costs and benefits of garbage collection in such systems.
Rendering optimisations for stylised sketching
Authors: Holger Winnemöller, Shaun Bangay
Venue: Proceedings of the 2nd international conference on Computer graphics, virtual Reality, visualisation and interaction in Africa (2003)

We present work that specifically pertains to the rendering stage of stylised, non-photorealistic sketching. While a substantial body of work has been published on geometric optimisations, surface topologies, space-algorithms and natural media simulation, rendering-specific issues are rarely discussed in-depth even though they are often acknowledged. We investigate the most common stylised sketching approaches and identify possible rendering optimisations. In particular, we define uncertainty-functions, which are used to describe a human-error component, discuss how these pertain to geometric perturbation and textured silhouette sketching and explain how they can be cached to improve performance. Temporal coherence, which poses a problem for textured silhouette sketching, is addressed by means of an easily computed visibility-function. Lastly, we produce an effective yet surprisingly simple solution to seamless hatching, which commonly presents a large computational overhead, by using 3-D textures in a novel fashion. All our optimisations are cost-effective, easy to implement and work in conjunction with most existing algorithms.
Extending standard UML with model composition semantics
Authors: Siobhán Clarke
Venue: Science of Computer Programming (2002)

There is a well documented problem in the software engineering field relating to a structural mismatch between the specification of requirements for software systems and the specification of object-oriented software systems. The structural mismatch happens because the units of interest during the requirements phase (for example, feature, service, capability, function, etc.) are different to the units of interest during object-oriented design and implementation (for example, object, class, method, etc.). The structural mismatch results in support for a single requirement being scattered across the design units and a single design unit supporting multiple requirements--this in turn results in reduced comprehensibility, traceability and reuse of design models.This paper presents an approach to designing systems based on the object-oriented model, but extending this model by adding new decomposition capabilities. The new decomposition capabilities support a way of directly aligning design models with individual requirements. Each model contains a design of an individual requirement, with concepts from the domain (which may appear in multiple requirements) designed from the perspective of that requirement. Standard UML is used to design the models decomposed in this way. Composition of design models is supported, and it is specified with a composition relationship. A composition relationship specifies how models are to be composed by identifying overlapping concepts in different models and specifying how models should be integrated. This paper describes changes required to the UML metamodel to support composition relationships. Two kinds of integration strategies are discussed--merge and override.
Implementation of Generalized Finite Element Methods for Homogenization Problems
Authors: A. W. Rüegg
Venue: Journal of Scientific Computing (2002)

The implementation of a generalized Finite Element Method (FEM) for problems with coefficients or geometry that oscillate locally at a small length scale &epsiv;&Lt;1 is described. Two-scale FE-spaces are combined conformingly with standard FE. Numerical experiments show that the complexity of the algorithm is independent of the micro length scale &epsiv;.
Point-based modelling and rendering using radial basis functions
Authors: Patrick Reuter, Ireneusz Tobor, Christophe Schlick, Sébastien Dedieu
Venue: Proceedings of the 1st international conference on Computer graphics and interactive techniques in Australasia and South East Asia (2003)

A point-based 3D surface modelling technique combined with a new point rendering technique is presented. Surfaces are modelled by specifying a set of unorganized points on the surface. An implicit representation of the surface through these points minimizing the bending energy is then calculated using radial basis functions while guaranteeing a specifiable continuity. The surface is directly rendered view-dependently in an output-sensitive multiresolution manner without the creation of a polygonal mesh representation. This is done by the local generation of 3D surface points for the rendering adapted to the output device. A new texturing technique using the material properties of the points is presented.
Vector-Based Arc Segmentation in the Machine Drawing Understanding System Environment
Authors: Dov Dori
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (1995)

Arcs are important primitives in engineering drawings. Along with bars, they play a major role in describing both the geometry and the annotation of the object represented in the drawing. Extracting these primitives during the lexical analysis phase is a prerequisite to syntactic and semantic understanding of engineering drawings within the Machine Drawing Understanding System. Bars are detected by the orthogonal zig-zag vectorization algorithm. Some of the detected bars are linear approximations of arcs. As such, they provide the basis for arc segmentation. An arc is detected by finding a chain of bars and a triplet of points along the chain. The arc center is first approximated as the center of mass of the triangle formed by the intersection of the perpendicular bisectors of the chords these points define. The location of the center is refined by recursively finding more such triplets and converging to within no more than a few pixels from the actual arc center after two or three iterations. The high performance of the algorithm, demonstrated on a set of real engineering drawings, is due to the fact that it avoids both raster-to-vector and massive pixel-level operations, as well as any space transformations.
A Digital Signal Processor with IEEE Floating-Point Arithmetic
Authors: Guy R. L. Sohie, Kevin L. Kloker
Venue: IEEE Micro (1988)

A overview is given of Motorola's DSP96002, a digital signal processor that implements IEEE-standard floating-point arithmetic. It is designed for graphics, image processing, spectral analysis and scientific computing applications. Performance peaks at 40.5 Mflops (million floating-point operations per second) and 13.5 MIPS (million instructions per second) and 18 Mflops on assembly-language benchmarks. The DSP is software-compatible with the fixed-point 56000/1 family architecture and instruction set. The 96002 achieves compatibility with other processors and databases, higher mathematical accuracy, and better error handling than implementations that do not conform to the IEEE standard. The 96002's on-chip memories, dual-bus architecture, and transparent DMA are suitable for multiprocessor systems in which many 96002s connect with minimum external components. These features result in a smaller-footprint, lower-cost system than other microprocessors or data-path chips. On-chip support for the fast access modes of external memories achieves near-SRAM (static random-access memory) performance with high-density DRAM/VRAM (dynamic RAM/virtual RAM) devices. An on-chip circuit emulation controller provides full access and control of the machine state for system debugging. A variety of software and hardware development tools support the 96002.
Once Upon A Time, There Was A Demo...
Authors: Guillermo Arango
Venue: IEEE Software (1995)

Computer technology, including software, has reached a point where it can beexcavated and studied archeologically. Such excavations can be very insightful:Several years ago, when I was building a program library for numericalcalculation, my mentor professor at Tokyo University was Ayao Amemiya. This man, who built Japan¿s first computer in 1952, brought me a dusty book, Acta Mathematics, written by L. Bourguet in 1883. We used the book to implementfomulas for Maclaurin expansion of a gamma function. Now Guillermo Arangohas unearthed another jewel, written 160 years ago. I hope you enjoy this treasure with an excavator¿s eye.
CASiNO: component architecture for simulating network objects
Authors: Abdella Battou, Bilal Khan, Daniel C. Lee, Spencer Marsh, Sean Mountcastle, David Talmage
Venue: Software&mdash;Practice Experience (2002)

We describe the Component Architecture for Simulating Network Objects (CASiNO) useful for the implementation of communication protocol stacks and network simulators. This framework implements a rich, modular coarse-grained dataflow architecture, with an interface to a reactor kernel that manages the application's handlers for asynchronous I/O, real timers and custom interrupts. These features enable developers to write applications that are driven by both data flow and asynchronous event delivery, while allowing them to keep these two functionalities distinct. We provide an example program and expository comments on the program to illustrate the use of the CASiNO framework.
Forwarders vs. centralized server: an evaluation of two approaches for locating mobile agents
Authors: Sara Alouf, Fabrice Huet, Philippe Nain
Venue: Performance Evaluation (2002)

This paper evaluates and compares the performance of two approaches for locating an agent in a mobile agent environment. The first approach dynamically creates a chain of forwarders to locate a moving agent, whereas the second one relies on a centralized server to perform this task. Based on a Markov chain analysis, we compute the performance of each scheme (time to reach an agent, number of forwarders) and compare them first with simulations and second with experimental results obtained by using ProActive, a Java library. Depending on the system parameters we identify the best scheme and observe that over a LAN the server yields the best performance, whereas the forwarders yield the best performance over a MAN.
Independently Updated Views
Authors: Uday R. Kulkarni, Richard G. Ramirez
Venue: IEEE Transactions on Knowledge and Data Engineering (1997)

Independently updated views (IUVs) are updated versions of a relational view. Unlike traditional views, updating an IUV changes only that IUV and not the underlying database. Updates to an IUV are stored in a differential table (DT) and incorporated when the IUV is accessed. There is no restriction on the type of query used to define the IUV. Applications of IUVs include alternative scenarios for decision support, local updating of distributed snapshots, and CAD versioning. IUVs allow versions to be defined on dynamic databases. This may cause inconsistencies because both the IUV and the base tables on which the IUV is defined can be updated independently of one another. We introduce "overlapping updates" that cause such inconsistencies and present algorithms for their detection and resolution using timestamps. These algorithms do not impose additional overhead on the database and require only the modification of the DT. A performance analysis indicates that the cost of querying IUVs is reasonable for a wide range of queries, views, and access strategies. We also consider a materialized implementation of IUVs. Materialized IUVs do not require a DT, relying instead on additional system columns for operation codes and timestamps. Results suggest a mix of implementation strategies for different types of IUV applications, depending on the frequency and nature of queries on the IUVs, the IUV sizes, and how actively the base tables are updated.
Joint Frequency and Symbol Synchronization Schemes for an OFDM System
Authors: Ching-P. Hung, Yu T. Su
Venue: Wireless Personal Communications: An International Journal (1999)

This paper proposes two multi-stage joint symbol timing and carrier frequency synchronization schemes for an orthogonal frequency division multiplex (OFDM) system. Simultaneous estimation of symbol timing and frequency offset is derived from the maximum likelihood (ML) principle, assuming a cyclic prefix (guard interval) is inserted in each OFDM symbol. One of the proposed algorithms derives an initial frequency estimate in the first stage that reduces the frequency uncertainty to only two or three sub-carrier spacings. The timing information and a finer frequency estimate that has a resolution of a sub-carrier spacing are obtained in the second stage. The third stage provides an estimation for the residual fractional frequency error. The other algorithm bypasses the first stage for one can use the second stage alone to search for the timing and frequency offsets. However, the computing complexity of the second stage is higher than that of the first stage, thus the three-stage algorithm is a preferred choice unless the frequency uncertainty is small. Simulation results show that both algorithms yield excellent performance not only in white Gaussian channels but also in multipath fading channels.
Starfire: Extending the SMP Envelope
Authors: Alan Charlesworth
Venue: IEEE Micro (1998)

The Sun Microsystems Starfire Ultra 10000 server is today's largest uniform-memory-access symmetric multiprocessor system. It uses an active centerplane with four address routers, and a 16x16 data crossbar to provide 64 processors with a memory bandwidth of 10,667 MBps. The use of point-to-point routers allows the system to be dynamically reconfigured into multiple hardware-protected operating system domains, with hot-swappable boards. This paper describes the interconnect implementation, and compares its price and performance to other multiprocessor architectures using the TPC-D benchmark.
Prediction of Performance and Processor Requirements in Real-Time Data Flow Architectures
Authors: S. Som, R. R. Mielke, J. W. Stoughton
Venue: IEEE Transactions on Parallel and Distributed Systems (1993)

Presents a new data flow graph model for describing the real-time execution of iterativecontrol and signal processing algorithms on multiprocessor data flow architectures.Identified by the acronym ATAMM, for Algorithm to Architecture Mapping Model, themodel is important because it specifies criteria for a multiprocessor operating system toachieve predictable and reliable performance. Algorithm performance is characterized byexecution time and iteration period. For a given data flow graph representation, the modelfacilitates calculation of greatest lower bounds for these performance measures. Whensufficient processors are available, the system executes algorithms with minimumexecution time and minimum iteration period, and the number of processors required iscalculated. When only limited processors are available or when processors fail,performance is made to degrade gracefully and predictably. The user off-line is able tospecify tradeoffs between increasing execution time or increasing iteration period. The approach to achieving predictable performance is to control the injection rate of inputdata and to modify the data flow graph precedence relations so that a processor isalways available to execute an enabled graph node. An implementation of the ATAMMmodel in a four-processor architecture based on Westinghouse's VHSIC 1750A Instruction Set Processor is described.
Digital Libraries
Authors: E. A. Fox
Venue: Computer (1993)

The history of modern information processing and the technology underlying it is reviewed. The development of hypertext is examined. Current technology and current efforts to expand information processing are discussed. The future of digital libraries is outlined.