ppxscal/embedding_network huggingface dataset:
A Scalable Architecture for MPEG-4 Wavelet Quantization
Authors: Bart Vanhoof, Mercedes Peón, Gauthier Lafruit, Jan Bormans, Lode Nachtergaele, Ivo Bolsens
Venue: Journal of VLSI Signal Processing Systems (1999)

Wavelet-based image compression has been adopted in MPEG-4 for visual texture coding. All wavelet quantization schemes in MPEG-4&mdash;Single Quantization (SQ), Multiple Quantization (MQ) and Bi-level Quantization&mdash;use Embedded Zero Tree (EZT) coding followed by an adaptive arithmetic coder for the compression and quantization of a wavelet image. This paper presents the OZONE chip, a dedicated hardware coprocessor for EZT and arithmetic coding. Realized in a 0.5 &mu;m CMOS technology and operating at 32 MHz, the EZT coder is capable of processing up to 25.6 Mega pixel-bitplanes per second. This is equivalent to the lossless compression of 31.6 8-bit grayscale CIF images (352 &times; 288) per second. The adaptive arithmetic coder processes up to 10 Mbit per second. The combination of the performance of the EZT coder and the arithmetic coder allows the OZONE to perform visual-lossless compression of more than 30 CIF images per second. Due to its novel and scalable architecture, parallel operation of multiple OZONEs is supported. The OZONE functionality is demonstrated on a PC-based compression system.
Displaced subdivision surfaces
Authors: Aaron Lee, Henry Moreton, Hugues Hoppe
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

In this paper we introduce a new surface representing, the displaced subdivision surface. It represents a detailed surface model as a scalar-valued displacement over a smooth domain surface. Our representation defines both the domain surface and the displacement function using a unified subdivision framework, allowing for simple and efficient evaluation of analytic surface properties. We present a simple, automatic scheme for converting detailed geometric models into such a representation. The challenge in this conversion process is to find a simple subdivision surface that still faithfully expresses the detailed model as its offset. We demonstrate that displaced subdivision surfaces offer a number of benefits, including geometry compression, editing, animation, scalability, and adaptive rendering. In particular, the encoding of fine detail as a scalar function makes the representation extremely compact.
Extendable, dispatchable task communication mechanisms
Authors: Stephen Michell, Kristina Lundqvist
Venue: Proceedings of the ninth international workshop on Real-time Ada (1999)

The addition of object-oriented features to Ada has left a disconnection between the object-oriented paradigm and the intertask communication and synchronisation paradigms. The lack of extensibility of tasks and protected types as well as the task synchronisation inheritance anomaly has made design of systems that use them with object oriented features more difficult. This paper proposes Ada language changes that would make protected types and tasks partners in object oriented programming and would cure the inheritance anomaly.
Trace-Based Abstract Interpretation of Operational Semantics
Authors: David A. Schmidt
Venue: Lisp and Symbolic Computation (1998)

We present trace-based abstract interpretation, a unification of several lines of research on applying Cousot-Cousot-style abstract interpretation a.i. to operational semantics definitions (such as flowchart, big-step, and small-step semantics) that express a program&lsquo;s semantics as a concrete computation tree of trace paths. A program&lsquo;s trace-based a.i. is also a computation tree whose nodes contain abstractions of state and whose paths simulate the paths in the program&lsquo;s concrete computation tree. Using such computation trees, we provide a simple explanation of the central concept of collecting semantics, and we distinguish concrete from abstract collecting semantics and state-based from path-based collecting semantics. We also expose the relationship between collecting semantics extraction and results garnered from flow-analytic and model-checking-based analysis techniques. We adapt concepts from concurrency theory to formalize &ldquo;safe&rdquo; and &ldquo;live&rdquo; a.i.&lsquo;s for computation trees; in particular, coinduction techniques help extend fundamental results to infinite computation trees.Problems specific to the various operational semantics methodologies are discussed: Big-step semantics cannot express divergence, so we employ a mixture of induction and coinduction in response; small-step semantics generate sequences of program configurations unbounded in size, so we abstractly interpret source language syntax. Applications of trace-based a.i. to data-flow analysis, model checking, closure analysis, and concurrency theory are demonstrated.
Priority Queues and Sorting Methods for Parallel Simulation
Authors: Miltos D. Grammatikakis, Stefan Liesche
Venue: IEEE Transactions on Software Engineering (2000)

We examine the design, implementation, and experimental analysis of parallel priority queues for device and network simulation. We consider: 1) distributed splay trees using MPI, 2) concurrent heaps using shared memory atomic locks, and 3) a new, more general concurrent data structure based on distributed sorted lists, which is designed to provide dynamically balanced work allocation (with automatic or manual control) and efficient use of shared memory resources. We evaluate performance for all three data structures on a Cray-T3E900 system at KFA-Jülich. Our comparisons are based on simulations of single buffers and a $64 \times 64$ packet switch which supports multicasting. In all implementations, PEs monitor traffic at their preassigned input/output ports, while priority queue elements are distributed across the Cray-T3E virtual shared memory. Our experiments with up to 60,000 packets and two to 64 PEs indicate that concurrent priority queues perform much better than distributed ones. Both concurrent implementations have comparable performance, while our new data structure uses less memory and has been further optimized. We also consider parallel simulation for symmetric networks by sorting integer conflict functions and implementing an interesting packet indexing scheme. The optimized message passing network simulator can process $\sim 500$K packet moves in one second, with an efficiency that exceeds $\sim 50$ percent for a few thousands packets on the Cray-T3E with 32 PEs. All developed data structures now form a parallel library. Although our concurrent implementations use the Cray-T3E ShMem library, portability can be derived from Open-MP or MPI-2 standard libraries, which will provide support for one-way communication and shared memory lock mechanisms.
TouchCounters: designing interactive electronic labels for physical containers
Authors: Paul Yarin, Hiroshi Ishii
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

We present TouchCounters, an integrated system of electronic modules, physical storage containers, and shelving surfaces for the support of collaborative physical work. Through physical sensors and local displays, TouchCounters record and display usage history information upon physical storage containers, thus allowing access to this information during the performance of real-world tasks. A distributed communications network allows this data to be exchanged with a server, such that users can access this information from remote locations as well. Based upon prior work in ubiquitous computing and tangible interfaces, TouchCounters incorporate new techniques, including usage history tracking for physical objects and multi-display visualization. This paper describes the components, interactions, implementation, and conceptual approach of the TouchCounters system.
Dynamically reparameterized light fields
Authors: Aaron Isaksen, Leonard McMillan, Steven J. Gortler
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

This research further develops the light field and lumigraph image-based rendering methods and extends their utility. We present alternate parameterizations that permit 1) interactive rendering of moderately sampled light fields of scenes with significant, unknown depth variation and 2) low-cost, passive autostereoscopic viewing. Using a dynamic reparameterization, these techniques can be used to interactively render photographic effects such as variable focus and depth-of-field within a light field. The dynamic parameterization is independent of scene geometry and does not require actual or approximate geometry of the scene. We explore the frequency domain and ray-space aspects of dynamic reparameterization, and present an interactive rendering technique that takes advantage of today's commodity rendering hardware.
A discussion of cybersickness in virtual environments
Authors: Joseph J. LaViola,  Jr.
Venue: ACM SIGCHI Bulletin (2000)

An important and troublesome problem with current virtual environment (VE) technology is the tendency for some users to exhibit symptoms that parallel symptoms of classical motion sickness both during and after the VE experience. This type of sickness, cybersickness, is distinct from motion sickness in that the user is often stationary but has a compelling sense of self motion through moving visual imagery. Unfortunately, there are many factors that can cause cybersickness and there is no foolproof method for eliminating the problem. In this paper, I discuss a number of the primary factors that contribute to the cause of cybersickness, describe three conflicting cybersickness theories that have been postulated, and discuss some possible methods for reducing cybersickness in VEs.
Distributed reconfiguration of metamorphic robot chains
Authors: Jennifer E. Walter, Jennifer L. Welch, Nancy M. Amato
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

The problem we address is the distributed reconfiguration of a metamorphic robotic system composed of any number of two dimensional hexagonal modules from specific initial to specific goal configurations. We present a distributed algorithm for reconfiguring a straight chain of hexagonal modules at one location to any intersecting straight chain configuration at some other location in the plane. We prove our algorithm is correct, and show that it is either optimal or asymptotically optimal in the number of moves and asymptotically optimal in the time required for parallel reconfiguration. We then consider the distributed reconfiguration of straight chains of modules to a more general class of goal configurations.
Locating and Computing Arbitrarily Distributed Zeros
Authors: D. J. Kavvadias, F. S. Makri, M. N. Vrahatis
Venue: SIAM Journal on Scientific Computing (1999)

The problem of locating and computing with certainty all the simple roots of a twice continuously differentiable function $f\colon [a,b] \subset $ ${\R } \to $ ${\R }$ is studied when some additional information on the distribution of the roots in the interval is available. The framework is the one proposed by [SIAM J. Sci. Comput., 17 (1996), pp. 1232--1248], where only the uniform case was examined. This paper settles some of the problems posed there and generalizes some of its results by considering an arbitrary distribution of the roots in [a,b]. The theoretical results are accompanied by simulations in a number of problems of various size.
Conjectural Equilibrium in Multiagent Learning
Authors: Michael P. Wellman, Junling Hu
Venue: Machine Learning (1998)

Learning in a multiagent environment is complicated by the fact that as other agents learn, the environment effectively changes. Moreover, other agents&lsquo; actions are often not directly observable, and the actions taken by the learning agent can strongly bias which range of behaviors are encountered. We define the concept of a conjectural equilibrium, where all agents&lsquo; expectations are realized, and each agent responds optimally to its expectations. We present a generic multiagent exchange situation, in which competitive behavior constitutes a conjectural equilibrium. We then introduce an agent that executes a more sophisticated strategic learning strategy, building a model of the response of other agents. We find that the system reliably converges to a conjectural equilibrium, but that the final result achieved is highly sensitive to initial belief. In essence, the strategic learner&lsquo;s actions tend to fulfill its expectations. Depending on the starting point, the agent may be better or worse off than had it not attempted to learn a model of the other agents at all.
Privacy-preserving data mining
Authors: Rakesh Agrawal, Ramakrishnan Srikant
Venue: ACM SIGMOD Record (2000)

A fruitful direction for future data mining research will be the development of techniques that incorporate privacy concerns. Specifically, we address the following question. Since the primary task in data mining is the development of models about aggregated data, can we develop accurate models without access to precise information in individual data records? We consider the concrete case of building a decision-tree classifier from training data in which the values of individual records have been perturbed. The resulting data records look very different from the original records and the distribution of data values is also very different from the original distribution. While it is not possible to accurately estimate original values in individual data records, we propose a novel reconstruction procedure to accurately estimate the distribution of original data values. By using these reconstructed distributions, we are able to build classifiers whose accuracy is comparable to the accuracy of classifiers built with the original data.
Energy-Efficient Mobile Cache Invalidation
Authors: Kun-Lung Wu, Philip S. Yu, Ming-Syan Chen
Venue: Distributed and Parallel Databases (1998)

Caching data in a wireless mobile computer can significantly reduce the bandwidth requirement. However, due to battery power limitation, a wireless mobile computer may often be forced to operate in a doze or even totally disconnected mode. As a result, the mobile computer may miss some cache invalidation reports. In this paper, we present an energy-efficient cache invalidation method for a wireless mobile computer. The new cache invalidation scheme is called grouping with cold update-set retention (GCORE). Upon waking up, a mobile computer checks its cache validity with the server. To reduce the bandwidth requirement for validity checking, data objects are partitioned into groups. However, instead of simply invalidating a group if any of the objects in the group has been updated, GCORE retains the cold update set of objects in a group if possible. We present an efficient implementation of GCORE and conduct simulations to evaluate its caching effectiveness. The results show that GCORE can substantially improve mobile caching by reducing the communication bandwidth (thus energy consumption) for query processing.
Editors&lsquo; Foreword: Intelligent Temporal Information Systems in Medicine
Authors: Yuval Shahar, Carlo Combi
Venue: Journal of Intelligent Information Systems (1999)

In this foreword, we first introduce the topics relevant to intelligent temporal information systems in medicine in general, and to the papers of this special issue in particular. We then provide a brief description of each paper. Finally, we describe the selection process for this special issue and thank the people who helped us put together the issue. We conclude with the list of the dedicated reviewers.
Tight Bounds for On-Line Tree Embeddings
Authors: Sandeep Bhatt, David Greenberg, Tom Leighton, Pangfeng Liu
Venue: SIAM Journal on Computing (1999)

Tree-structured computations are relatively easy to process in parallel. As leaf processes are recursively spawned they can be assigned to independent processors in a multicomputer network. However, to achieve good performance the on-line mapping algorithm must maintain load balance, i.e., distribute processes equitably among processors. Additionally, the algorithm itself must be distributed in nature, and process allocation must be completed via message-passing with minimal communication overhead.This paper investigates bounds on the performance of deterministic and randomized algorithms for on-line tree embeddings. In particular, we study trade-offs between computation overhead (load imbalance) and communication overhead (message congestion). We give a simple technique to derive lower bounds on the congestion that any on-line allocation algorithm must incur in order to guarantee load balance. This technique works for both randomized and deterministic algorithms. We prove that the advantage of randomization is limited. Optimal bounds are achieved for several networks, including multidimensional grids and butterflies.
Monte Carlo evaluation of non-linear scattering equations for subsurface reflection
Authors: Matt Pharr, Pat Hanrahan
Venue: Proceedings of the 27th annual conference on Computer graphics and interactive techniques (2000)

We describe a new mathematical framework for solving a wide variety of rendering problems based on a non-linear integral scattering equation. This framework treats the scattering functions of complex aggregate objects as first-class rendering primitives; these scattering functions accurately account for all scattering events inside them. We also describe new techniques for computing scattering functions from the composition of scattering objects. We demonstrate that solution techniques based on this new approach can be more efficient than previous techniques based on radiance transport and the equation of transfer and we apply these techniques to a number of problems in rendering scattering from complex surfaces.
Laziness pays! using lazy synchronization mechanisms to improve non-blocking constructions
Authors: Mark Moir
Venue: Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing (2000)

We present a simple and efficient wait-free implementation of Lazy Large Load-Linked/Store-Conditional (Lazy-LL/SC), which can be used to atomically modify a dynamically-determined set of shared variables in a lock-free manner. The semantics of Lazy-LL/SC is weaker than that of similar objects used by us previously to design lock-free and wait-free constructions, and as a result can be implemented more efficiently. However, we show that Lazy-LL/SC is strong enough to be used in existing non-blocking universal constructions and to build new ones.
A Randomized Fully Polynomial Time Approximation Scheme for the All-Terminal Network Reliability Problem
Authors: David R. Karger
Venue: SIAM Journal on Computing (1999)

The classic all-terminal network reliability problem posits a graph, each of whose edges fails independently with some given probability. The goal is to determine the probability that the network becomes disconnected due to edge failures. This problem has obvious applications in the design of communication networks. Since the problem is $\SP$-complete and thus believed hard to solve exactly, a great deal of research has been devoted to estimating the failure probability. In this paper, we give a fully polynomial randomized approximation scheme that, given any n-vertex graph with specified failure probabilities, computes in time polynomial in n and $1/\epsilon$ an estimate for the failure probability that is accurate to within a relative error of $1\pm\epsilon$ with high probability. We also give a deterministic polynomial approximation scheme for the case of small failure probabilities. Some extensions to evaluating probabilities of k-connectivity, strong connectivity in directed Eulerian graphs and r-way disconnection, and to evaluating the Tutte polynomial are also described.
New clock-gating techniques for low-power flip-flops
Authors: A. G. M. Strollo, E. Napoli, D. De Caro
Venue: Proceedings of the 2000 international symposium on Low power electronics and design (2000)

Two novel low power flip-flops are presented in the paper. Proposed flip-flops use new gating techniques that reduce power dissipation deactivating the clock signal. Presented circuits overcome the clock duty-cycle limitation of previously reported gated flip-flops.Circuit simulations with the inclusion of parasitics show that sensible power dissipation reduction is possible if input signal has reduced switching activity. A 16-bit counter is presented as a simple low power application.
Low-power micromachined microsystems (invited talk)
Authors: Khalil Najafi
Venue: Proceedings of the 2000 international symposium on Low power electronics and design (2000)

Micromachined microsystems and Micro Electro Mechanical Systems (MEMS) have made possible the development of highly accurate and portable sensors and instrument for a variety of applications in the health care, industrial, consumer products, avionics, and defense. Design of low-power circuits for these applications, and use of micromachined sensors and actuators in combination with integrated circuits to implement even lower power microinstruments has now become possible and the focus of attention. This paper reviews the state of the art in the development of micromachined microsystems and MEMS, discusses low-power design approaches for microsystems, and reviews some recent development in power generation and energy harvesting from the environment.
Geometric Mesh Partitioning: Implementation and Experiments
Authors: John R. Gilbert, Gary L. Miller, Shang-Hua Teng
Venue: SIAM Journal on Scientific Computing (1998)

We investigate a method of dividing an irregular mesh into equal-sized pieces with few interconnecting edges. The method's novel feature is that it exploits the geometric coordinates of the mesh vertices. It is based on theoretical work of Miller, Teng, Thurston, and Vavasis, who showed that certain classes of "well-shaped" finite-element meshes have good separators. The geometric method is quite simple to implement: we describe a \sc Matlab code for it in some detail. The method is also quite efficient and effective: we compare it with some other methods, including spectral bisection.
Hybrid Fault Simulation for Synchronous Sequential Circuits
Authors: Bernd Becker, Martin Keim, Rolf Krieger
Venue: Journal of Electronic Testing: Theory and Applications (1999)

We present a fault simulator for synchronous sequential circuits that combines the efficiency of three-valued logic simulation with the exactness of a symbolic approach. The simulator is hybrid in the sense that three different modes of operation&mdash;three-valued, symbolic and mixed&mdash;are supported. We demonstrate how an automatic switching between the modes depending on the computational resources and the properties of the circuit under test can be realized, thus trading off time/space for accuracy of the computation. Furthermore, besides the usual Single Observation Time Test Strategy (SOT) for the evaluation of the fault coverage, the simulator supports evaluation according to the more general Multiple Observation Time Test Strategy (MOT). Numerous experiments are given to demonstrate the feasibility and efficiency of our approach. In particular, it is shown that, at the expense of a reasonable time penalty, the exactness of the fault coverage computation can be improved even for the largest benchmark functions.
Computational geometry
Authors: Pankaj K. Agarwal, Joseph O'Rourke
Venue: ACM SIGACT News (1998)

Problems presented at the open-problem session of the 14th Annual ACM Symposium on Computational Geometry are listed.
Counting Unbranched Subgraphs
Authors: David Ruelle
Venue: Journal of Algebraic Combinatorics: An International Journal (1999)

Given an arbitrary finite graph, the polynomial Q(z) &equals; &Sigma;F &isin; Uz cardF associates a weight zcardF to each unbranched subgraph F of length cardF. We show that all the zeros of Q have negative real part.