ppxscal/embedding_network huggingface dataset:
Tests of probabilistic models for propagation of roundoff errors
Authors: T. E. Hull, J. R. Swenson
Venue: Communications of the ACM (1966)

In any prolonged computation it is generally assumed that the accumulated effect of roundoff errors is in some sense statistical. The purpose of this paper is to give precise descriptions of certain probabilistic models for roundoff error, and then to describe a series of experiments for testing the validity of these models. It is concluded that the models are in general very good. Discrepancies are both rare and mild. The test techniques can also be used to experiment with various types of special arithmetic.
An integrated scheme for object-based video abstraction
Authors: Changick Kim, Jenq-Neng Hwang
Venue: Proceedings of the eighth ACM international conference on Multimedia (2000)

In this paper, we present a novel scheme for object-based key-frame extraction facilitated by an efficient video object segmentation system. Key-frames are the subset of still images which best represent the content of a video sequence in an abstracted manner. Thus, key-frame based video abstraction transforms an entire video clip to a small number of representative images. The challenge is that the extraction of key-frames needs to be automated and context dependent so that they maintain the important contents of the video while remove all redundancy. Among various semantic primitives of video, objects of interest along with their actions and generated events can play an important role in some applications such as object-based video surveillance system. Furthermore, on-line processing combined with fast and robust video object segmentation is crucial for real-time applications to report unwanted action or event as soon as it happens. Experimental results on the proposed scheme for object-based video abstraction are presented.
Learning Markov networks: maximum bounded tree-width graphs
Authors: David Karger, Nathan Srebro
Venue: Proceedings of the twelfth annual ACM-SIAM symposium on Discrete algorithms (2001)

Markov networks are a common class of graphical models used in machine learning. Such models use an undirected graph to capture dependency information among random variables in a joint probability distribution. Once one has chosen to use a Markov network model, one aims to choose the model that &ldquo;best explains&rdquo; the data that has been observed&mdash;this model can then be used to make predictions about future data. We show that the problem of learning a maximum likelihood Markov network given certain observed data can be reduced to the problem of identifying a maximum weight low-treewidth graph under a given input weight function. We give the first constant factor approximation algorithm for this problem. More precisely, for any fixed treewidth objective k, we find a treewidth-k graph with an f(k) fraction of the maximum possible weight of any treewidth-k graph.
Runtime optimizations for a Java DSM implementation
Authors: R. Veldema, R. F. H. Hofman, R. A. F. Bhoedjang, H. E. Bal
Venue: Proceedings of the 2001 joint ACM-ISCOPE conference on Java Grande (2001)

Jackal is a fine-grained distributed shared memory implementation of the Java programming language. Jackal implements Java's memory model and allows multithreaded Java programs to run unmodified on distributed-memory systems. This paper focuses on Jackal's runtime system, which implements a multiple-writer, home-based consistency protocol. Protocol actions are triggered by software access checks that Jackal's compiler inserts before object and array references. We describe optimizations for Jackal's runtime system, which mainly consist of discovering opportunities to dispense with flushing of cached data. We give performance results for different runtime optimizations, and compare their impact with the impact of one compiler optimization. We find that our runtime optimizations are necessary for good Jackal performance, but only in conjunction with the Jackal compiler optimizations described in [24]. As a yardstick, we compare the performance of Java applications run on Jackal with the performance of equivalent applications that use a fast implementation of Java's Remote Method Invocation (RMI) instead of shared memory.
A conceptual framework for network and client adaptation
Authors: B. Badrinath, Armando Fox, Leonard Kleinrock, Gerald Popek, Peter Reiher, M. Satyanarayanan
Venue: Mobile Networks and Applications (2000)

Modern networks are extremely complex, varying both statically and dynamically. This complexity and dynamism are greatly increased when the network contains mobile elements. A number of researchers have proposed solutions to these problems based on dynamic adaptation to changing network conditions and application requirements. This paper summarizes the results of several such projects and extracts several important general lessons learned about adapting data flows over difficult network conditions. These lessons are then formulated into a conceptual framework that demonstrates how a few simple and powerful ideas can describe a wide variety of different software adaptation systems. This paper describes an Adaptation Framework in the context of the several successful adaptation systems and suggests how the framework can help researchers think about the problems of adaptivity in networks.
Fast hierarchical clustering and other applications of dynamic closest pairs
Authors: David Eppstein
Venue: Journal of Experimental Algorithmics (JEA) (2000)

We develop data structures for dynamic closest pair problems with arbitrary distance functions, that do not necessarily come from any geometric structure on the objects. Based on a technique previously used by the author for Euclidean closest pairs, we show how to insert and delete objects from an <i>n</i>-object set, maintaining the closest pair, in <i>O</i>(<i>n</i> log<sup>2</sup> <i>n</i>) time per update and <i>O</i>(<i>n</i>) space. With quadratic space, we can instead use a quadtree-like structure to achieve an optimal time bound, <i>O</i>(<i>n</i>) per update. We apply these data structures to hierarchical clustering, greedy matching, and TSP heuristics, and discuss other potential applications in machine learning, Gröbner bases, and local improvement algorithms for partition and placement problems. Experiments show our new methods to be faster in practice than previously used heuristics.
Evaluation of Fast Rotation Methods
Authors: Gerben Hekstra
Venue: Journal of VLSI Signal Processing Systems (2000)

In this paper, we present a comprehensive inventory and evaluation of fast rotation methods. Fast rotations are arithmetic methods for performing orthonormal rotation at a very low cost in implementation. We show that there are different implementation forms for fast rotations, and propose a classification for them. We compare fast rotation methods with a direct form and with a factored form implementation, and examine the trade-offs that existbetween the angle of rotation, the accuracy in scaling, and the cost of performing the rotation.
Using a theoretical multimedia taxonomy framework
Authors: Rachelle S. Heller, C. Dianne Martin, Nuzi Haneef, Sonja Gievska-Krliu
Venue: Journal on Educational Resources in Computing (JERIC) (2001)

Multimedia (MM) is a polysemous term, a term with many definitions, and in this case, many roots. In this paper, multimedia is defined as the seamless integration of two or more media. Each ancestor brings another requirement, muddying the field and making it difficult to work through. A multimedia taxonomy based on a previous media taxonomy is proposed to help organize the discipline. The taxonomy helps to classify the space called multimedia and to draw attention to difficult issues. The paper outlines the forms contributing to multimedia&mdash;text, sound, graphics, and motion&mdash;and aligns them with probable formats&mdash;elaboration, representation, and abstraction&mdash; and sets them within a context&mdash;audience, discipline, interactivity, quality, usefulness, and aesthetics. The contexts are more clearly defined in two areas: interactivity and the information basis for a discipline. Examples are presented describing the use of the taxonomy in the design and evaluation of student projects in a computer science-based multimedia course.
Application of automated design migration to alternating phase shift mask design
Authors: Fook-Luen Heng, Lars Liebmann, Jennifer Lund
Venue: Proceedings of the 2001 international symposium on Physical design (2001)

The use of phase shifted mask (PSM) has been demonstrated to be a powerful resolution enhancement technique (RET) for the printing of features at dimensions below the exposure wavelength in deep submicron technologies. Its implementation in physical design has introduced non-conventional design ground rules, which impact the traditional layout migration process and designers productivity. In this panel discussion paper, we propose a solution to extend the traditional constraint-based layout migration and legalization approach. The solution has been demonstrated to be very effective in practice.
Finding minimum congestion spanning trees
Authors: Renato Werneck, João Setubal
Venue: Journal of Experimental Algorithmics (JEA) (2000)

Given a weighted graph <i>G = (V, E)</i>, a positive integer <i>k</i>, and a penalty function <i>w<inf>p</inf></i>, we want to find <i>k</i> spanning trees on <i>G</i>, not necessarily disjoint, of minimum total weight, such that the weight of each edge is subject to a penalty given by <i>w<inf>p</inf></i> if it belongs to more than one tree. The objective function to be minimized is Σ<i><inf>e∈E</inf>W<inf>e</inf>(i<inf>e</inf>)</i>, where <i>i<inf>e</inf></i> is the number of times edge <inf>e</inf> appears in the solution and <i>W<inf>e</inf>(i<inf>e</inf>) = i<inf>e</inf>w<inf>p</inf>(e, i<inf>e</inf>)</i> is the aggregate cost of using edge <i>e i<inf>e</inf></i> times. For the case when <i>W<inf>e</inf></i> is weakly convex, which should have wide application in congestion problems, we present a polynomial time algorithm; the algorithm's complexity is quadratic in <i>k</i>. We also present two heuristics with complexity linear in <i>k</i>. In an experimental study we show that these heuristics are much faster than the exact algorithm also in practice. These experiments present a diverse combination of input families (four), varying <i>k</i> (up to 1000), and penalty functions (two). In most inputs tested the solutions given by the heuristics were within 1% of optimal or much better, especially for large <i>k</i>. The worst quality observed was 3.2% of optimal.
Constant-time filtering with space-variant kernels
Authors: Alain Fournier, Eugene Fiume
Venue: Proceedings of the 15th annual conference on Computer graphics and interactive techniques (1988)

Filtering is an essential but costly step in many computer graphics applications, most notably in texture mapping. Several techniques have been previously developed which allow prefiltering of a texture (or in general an image) in time that is independent of the number of texture elements under the filter kernel. These are limited, however, to space-invariant kernels whose shape in texture space is the same independently of their positions, and usually are also limited to a small range of filters.We present here a technique that permits constant-time filtering for space-variant kernels. The essential step is to approximate a filter surface in texture space by a sum of suitably-chosen basis functions. The convolution of a filter with a texture is replaced by the weighted sum of the convolution of the basis functions with the texture, which can be precomputed. To achieve constant time, convolutions with the basis functions are computed and stored in a pyramidal fashion, and the right level of the pyramid is selected so that only a constant number of points on the filter kernel need be evaluated.The technique allows the use of arbitrary filters, and as such is useful to explore interesting mappings and special filtering techniques. We give examples of applications to perspective and conformal mappings, and to the use of filters such as gaussians and sinc functions.
Collaborative virtual environments in the year of the dragon
Authors: Samuli Pekkola, Mike Robinson, Markku-Juhani O. Saarinen, Jonni Korhonen, Saku Hujala, Tero Toivonen
Venue: Proceedings of the third international conference on Collaborative virtual environments (2000)

Three suggestions are made for extensions from and to CVE's: awareness of others, multiple media, and scalability. Awareness of others and their activities is strongly desirable in all media and applications, not just in CVE's. Multiple media are not seriously catered for in existing CVE's, and a suitable architecture will precede popular applications. CVE's need to be scalable to greater numbers of people, and achieving this also has implications for greater flexibility and reconfigurability. With respect to awareness of others, we argue that the Web and most document handling applications are unaware of others in the workgroup or community, and this limits the ability to support real work practice. We present a Web application (CRACK!) that provides 'people-awareness' in the Web, between the Web and VR's, and that should be extensible to other standard document handling programs. With respect to multiple media, we argue that many media are needed for collaboration, since each has its own special benefits and affordances. We present a scalable architecture for handling multiple media (VR, video, audio, text, and documents). An important feature of the architecture is that the presentation level integration. With respect to scalability we note that upward scalability is important as it also gives a new ability to join, re-divide, and thus create new 'worlds'. We give an example of a novel dynamic partitioning algorithm to achieve upward scalability. We argue that 'downward' scalability to e.g. mobiles, and 'sideways scalability' to specialist e.g. audio or video devices is important in achieving multiple media CVE's. Taken together, these innovations may stimulate new generations of CVE's.
Graphical user interface of FIESTA—software for faults identification and estimation of testability of VLSI circuits
Authors: Mykola Blyzniuk, Taras Panchak, Wieslaw Kuzmicz, Witold Pleskacz
Venue: Proceedings of the symposium on Contemporary computing in Ukraine (2000)

We present the graphical user interface (GUI) of FIESTA software tools. It is based on the proposed principles of open systems development. FIESTA was designed as UNIX application and works under Solaris 2.5.1. Graphical user interface of FIESTA has been developed with the use of Tel/Tk 8.2 design environment.
Computer simulations of diffusion-limited reactions
Authors: Roan Dawkins, Daniel Ben-Avraham
Venue: Computing in Science and Engineering (2001)

In many situations it is possible to model a system by entities that diffuse and occasionally react upon encounter. Examples include chemical reactions, electron-hole recombination, annealing of defects in crystals, interacting excitons (solitons, photoexcited states, and so on), predator-prey models, and the spreading of ideas through social intercourse. For concreteness and without loss of generality, we shall refer to the interacting entities as particles.
Thread-specific heaps for multi-threaded programs
Authors: Bjarne Steensgaard
Venue: Proceedings of the 2nd international symposium on Memory management (2000)

Garbage collection for a multi-threaded program typically involves either stopping all threads while doing the collection or involves copious amounts of synchronization between threads. However, a lot of data is only ever visible to a single thread, and such data should ideally be collected without involving other threads. Given an escape analysis, a memory management system may allocate thread-specific data in thread-specific heaps and allocate shared data in a shared heap. Garbage collection of data in a thread-specific heaps can be done independent of other threads and of data in their thread-specific heaps. For multi-threaded programs, thread-specific heaps allow reduced garbage collection latency for active threads. On multi-processor computers, thread-specific heaps allow concurrent garbage collection of different thread-specific heaps with minimal synchronization overhead. We present an escape analysis and a sample memory management system using thread-specific heaps.
A precise numerical analysis program
Authors: Oliver Aberth
Venue: Communications of the ACM (1974)

A description is given of a program for computing the solution to a small number of standard numerical analysis problems to any specified accuracy, up to a limit of 2000 correct decimal places. Each computed number is bounded in an interval with a multiple precision midpoint. Arithmetic operations involving these numbers are executed according to interval arithmetic concepts, with non-significant digits automatically discarded. Details are supplied of problem specification and problem computation.
Addition in an arbitrary base without radix conversion
Authors: Stephen Soule
Venue: Communications of the ACM (1975)

hnique; using it, one may add and subtract numbers represented in any radix, including a mixed radix, and stored one digit per byte in bytes of sufficient size. Radix conversion is unnecessary, no looping is required, and numbers may even be stored in a display (I/O) format. Applications to Cobol, MIX, and hexadecimal sums are discussed.
Collapsing the transistor chain to an effective single equivalent transistor
Authors: A. Chatzigeorigiou, S. Nikolaidis
Venue: Proceedings of the conference on Design, automation and test in Europe (1998)

The most common practice to model the transistor chain, as it appears in CMOS gates, is to collapse it to a single equivalent transistor. This method is analyzed and improvements are presented in this paper. Inherent shortcomings are removed and an effective transistor width is calculated taking into account the operating conditions of the structure, resulting in very good agreement with SPICE simulations. The actual time point when the chain starts conducting which influences significantly the accuracy of the model is also extracted. Finally, an algorithm to collapse every possible input pattern to a single input is presented.
Adaptive correction of program statements
Authors: E. B. James, D. P. Partridge
Venue: Communications of the ACM (1973)

A method of analyzing statements in a programming language which can tolerate a considerable inaccuracy in their specification is proposed. This method involves principles at present mainly confined to studies in the area of artificial intelligence such as feature extraction, approximate tree matching, and strategy improvement by feedback from the matching process. A pilot program incorporating the principles is described and preliminary operating results are presented. A final section surveys further principles which are currently being investigated.
Typed memory management via static capabilities
Authors: David Walker, Karl Crary, Greg Morrisett
Venue: ACM Transactions on Programming Languages and Systems (TOPLAS) (2000)

Region-based memory management is an alternative to standard tracing garbage collection that makes operation such as memory deallocation explicit but verifiably safe. In this article, we present a new compiler intermediate language, called the Capability Language (CL), that supports region-based memory management and enjoys a provably safe type systems. Unlike previous region-based type system, region lifetimes need not be lexically scoped, and yet the language may be checked for safety without complex analyses. Therefore, our type system may be deployed in settings such as extensible operating systems where both the performance and safety of untrusted code is important. The central novelty of the language is the use of static capabilities to specify the permissibility of various operations, such as memory access and deallocation. In order to ensure capabilities are relinquished properly, the type system tracks aliasing information using a form of bounded quantification. Moreover, unlike previous work on region-based type systems, the proof of soundness of our type system is relatively simple, employing only standard syntactic techniques. In order to show how our language may be used in practice, we show how to translate a variant of Tofte and Talpin's high-level type-and-effects system for region-based memory management into our language. When combined with known region inference algorithms, this translation provides a way to compile source-level languages to CL.
Optimal Sequence of Inter-GenerationalBorrowing and Lending Leading to Escape fromthe Poverty Trap through an Invisible Hand
Authors: Mehrdaad Ghorashi
Venue: Computational Economics (2000)

The overlapping generations (OLG) model of micro-based macroeconomics has been utilized in order to calculate the optimal sequence of inter-generational transfer payments and evaluate its effects on the operation of an economy which suffers from the poverty trap. Each generation has been assumed to live for two periods and aims to find the optimal relationship between its borrowing from the previous generation and its lending to the next generation so that its discounted utility function is maximized. This optimization is subjected to budget constraints, the competitiveness of labor and capital markets and the equilibrium condition of savings and capital. Individuals in all of the generations are assumed to pay no attention to the utility level of the next generation (i.e. they do not have altruism). Furthermore, government limits the domain of choices of the generations with the additional constraint that the borrowing and lending amounts of each generation should be positively correlated. Each generation, when it compares its discounted utility levels corresponding to the two options &ndash; i.e. participation in the payment system or not, assuming perfect information &ndash; understands that participation in the system is beneficial and thus wishes to share in the payments system. This participation consists of two parts, one is borrowing when young (saving together with consuming), and the other is lending when old (consuming only). A moral hazard may thus occur due to the fact that the young generation after borrowing decides not to pay its share back to the new young generation when it becomes old. Thus, the government is also necessary in order to prevent this moral hazard. However, no special objective function of the government enters the problem formulation. It is observed that, as an important side effect, the sequence of transfer payments obtained can not only bring the economy out of the poverty trap, but it also raises the stable equilibrium level of the capital-labor ratio to a level higher than that is achievable by a comparable competitive economy without transfer payments. The steady-state obtained has another advantage over the competitive equilibrium, viz., such an improved equilibrium is dynamically efficient and in this equilibrium the economy would operate within the golden rule situation. These side effects, which are the benefits received by the whole economy as a result of the decisions made by selfish generations, seem to be inter-generational interpretations of the Invisible Hand concept of Adam Smith.
Notes on recursion elimination
Authors: R. S. Bird
Venue: Communications of the ACM (1977)

Various methods of recursion elimination are applied to the schematic recursive procedure: proc S(x); px then N(x); S(&fnof;x); S(gx); M(x) fi. Procedures with this general form arise in connection with tree traversal and sorting algorithms. Each method of recursion removal involves the use of one or more stacks, and the solutions are compared on the basis of their running time.