ppxscal/embedding_network huggingface dataset:
Prequential and Cross-Validated Regression Estimation
Authors: Dharmendra S. Modha, Elias Masry
Venue: Machine Learning (1998)

Prequential model selection and delete-one cross-validation are data-driven methodologies for choosing between rival models on the basis of their predictive abilities. For a given set of observations, the predictive ability of a model is measured by the model&lsquo;s accumulated prediction error and by the model&lsquo;s average-out-of-sample prediction error, respectively, for prequential model selection and for cross-validation. In this paper, given i.i.d. observations, we propose nonparametric regression estimators&mdash;based on neural networks&mdash;that select the number of &ldquo;hidden units&rdquo; (or &ldquo;neurons&rdquo;) using either prequential model selection or delete-one cross-validation. As our main contributions: (i) we establish rates of convergence for the integrated mean-squared errors in estimating the regression function using &ldquo;off-line&rdquo; or &ldquo;batch&rdquo; versions of the proposed estimators and (ii) we establish rates of convergence for the time-averaged expected prediction errors in using &ldquo;on-line&rdquo; versions of the proposed estimators. We also present computer simulations (i) empirically validating the proposed estimators and (ii) empirically comparing the proposed estimators with certain novel prequential and cross-validated &ldquo;mixture&rdquo; regression estimators.
Components of Software Development Risk: How to Address Them? A Project Manager Survey
Authors: Janne Ropponen, Kalle Lyytinen
Venue: IEEE Transactions on Software Engineering (2000)

Software risk management can be defined as an attempt to formalize risk oriented correlates of development success into a readily applicable set of principles and practices. By using a survey instrument we investigate this claim further. The investigation addresses the following questions: 1) What are the components of software development risk? 2) how does risk management mitigate risk components, and 3) what environmental factors if any influence them? Using principal component analysis we identify six software risk components: 1) scheduling and timing risks, 2) functionality risks, 3) subcontracting risks, 4) requirements management, 5) resource usage and performance risks, and 6) personnel management risks. By using one-way ANOVA with multiple comparisons we examine how risk management (or the lack of it) and environmental factors (such as development methods, manager's experience) influence each risk component. The analysis shows that awareness of the importance of risk management and systematic practices to manage risks have an effect on scheduling risks, requirements management risks, and personnel management risks. Environmental contingencies were observed to affect all risk components. This suggests that software risks can be best managed by combining specific risk management considerations with a detailed understanding of the environmental context and with sound managerial practices, such as relying on experienced and well-educated project managers and launching correctly sized projects.
The psychology of multimedia databases
Authors: Mark G. L. M. van Doorn, Arjen P. de Vries
Venue: Proceedings of the fifth ACM conference on Digital libraries (2000)

Multimedia information retrieval in digital libraries is a difficult task for computers in general. Humans on the other hand are experts in perception, concept representation, knowledge organization and memory retrieval. Cognitive psychology and science describe how cognition works in humans, but can offer valuable clues to information retrieval researchers as well. Cognitive psychologists view the human mind as a general-purpose Ysymbol-processing system that interacts with the world. A multimedia Yinformation retrieval system can also be regarded as a symbol-processing system that interacts with the environment. Its underlying information retrieval model can be seen as a cognitive framework that describes how the describe the design and implementation of a combined text/image retrieval system (as an example of a multimedia retrieval system) that is inspired by cognitive theories such as Paivio's dual coding theory and Marr's theory of perception. User interaction and an automatically created thesaurus that maps text concepts and internal image concept representations, generated by various feature extraction algorithms, improve the query formulation process of the image retrieval system. Unlike most``multimedia databases'' found in literature, this image retrieval system uses the the functionality provided by an extensible multimedia DBMSthat itself is part of an open distributed environment.
Effective jump-pointer prefetching for linked data structures
Authors: Amir Roth, Gurindar S. Sohi
Venue: ACM SIGARCH Computer Architecture News (1999)

Current techniques for prefetching linked data structures (LDS) exploit the work available in one loop iteration or recursive call to overlap pointer chasing latency. Jump pointers, which provide direct access to non-adjacent nodes, can be used for prefetching when loop and recursive procedure bodies are small and do not have sufficient work to overlap a long latency. This paper describes a framework for jump-pointer prefetching (JPP) that supports four prefetching idioms: queue, full, chain, and root jumping and three implementations: software-only, hardware-only, and a cooperative software/hardware technique. On a suite of pointer intensive programs, jump pointer prefetching reduces memory stall time by 72% for software, 83% for cooperative and 55% for hardware, producing speedups of 15%, 20% and 22% respectively.
Assigning codes in wireless networks: bounds and scaling properties
Authors: Roberto Battiti, Alan A. Bertossi, Maurizio A. Bonuccelli
Venue: Wireless Networks (1999)

In the Code Division Multiple Access (CDMA) framework, collisions that can occur in wireless networks are eliminated by assigning orthogonal codes to stations, a problem equivalent to that of coloring graphs associated to the physical network. In this paper we present new upper and lower bounds for two versions of the problem (hidden and primary collision avoidance &ndash; HP-CA &ndash; or hidden collision avoidance only &ndash; H-CA). In particular, optimal assignments for special topologies and heuristics for general topologies are proposed. The schemes show better average results with respect to existing alternatives. Furthermore, the gaps between the upper bound given by the heuristic solution, the lower bound obtained from the maximum-clique problem, and the optimal solution obtained by branch and bound are investigated in the different settings. A scaling law is then proposed to explain the relations between the number of codes needed in Euclidean networks with different station densities and connection distances. The substantial difference between the two versions HP-CA and H-CA of the problem is investigated by studying the probabilistic distribution of connections as a function of the distance, and the asymptotic size of the maximum cliques.
Combining tasking and transaction
Authors: Jörg Kienzle
Venue: Proceedings of the ninth international workshop on Real-time Ada (1999)

This position paper discusses the issues in design and development of a transaction support for Ada 95. Transactions and other fault tolerance mechanisms are reviewed, and their applicability in a concurrent programming language is analyzed. Possible ways of integration are presented, and implementation problems are discussed.
Comparing the effectiveness of fine-grain memory caching against page migration/replication in reducing traffic in DSM clusters
Authors: An-Chow Lai, Babak Falsafi
Venue: Proceedings of the twelfth annual ACM symposium on Parallel algorithms and architectures (2000)

In this paper, we compare and contrast two techniques to improve capacity/conflict miss traffic in CC-NUMA DSM clusters. Page migration/replication optimizes read-write accesses to a page used by a single processor by migrating the page to that processor and replicates all read-shared pages in the sharers' local memories. R-NUMA optimizes read-write accesses to any page by allowing a processor to cache that page in its main memory. Page migration/replication requires less hardware complexity as compared to R-NUMA, but has limited applicability and incurs much higher overheads even with tuned hardware/software support. In this paper, we compare and contrast page migration/replication and R-NUMA on simulated clusters of symmetric multiprocessors executing shared-memory applications. Our results show that: (1) both page migration/replication and R-NUMA significantly improve the system performance over &ldquo;first-touch&rdquo; migration in many applications, (2) page migration/replication has limited opportunity and can not eliminate all the capacity/conflict misses even with fast hardware support and unlimited amount of memory, (3) R-NUMA always performs best given a page cache large enough to fit an application's primary working set and subsumes page migration/replication, (4) R-NUMA benefits more from hardware support to accelerate page operations than page migration/replication, and (5) integrating page migration/replication into R-NUMA to help reduce the hardware cost requires sophisticated mechanisms and policies to select candidates for page migration/replication.
Using the visual differences predictor to improve performance of progressive global illumination computation
Authors: Valdimir Volevich, Karol Myszkowski, Andrei Khodulev, Edward A. Kopylov
Venue: ACM Transactions on Graphics (TOG) (2000)

A novel view-independent technique for progressive global illumination computing that uses prediction of visible differences to improve both efficiency and effectiveness of physically-sound lighting solutions has been developed. The technique is a mixture of stochastic (density estimation) and deterministic (adaptive mesh refinement) algorithms used in a sequence and optimized to reduce the differences between the intermediate and final images as perceived by the human observer in the course of lighting computation. The quantitive measurements of visibility were obtained using the model of human vision captured in the visible differences predictor (VDP) developed by Daly [1993]. The VDP responses were used to support the selection of the best component algorithms from a pool of global illumination solutions, and to enhance the selected algorithms for even better progressive refinement of image quality. The VDP was also used to determine the optimal sequential order of component-algorithm execution, and to choose the points at which switchover between algorithms should take place. As the VDP is computationally expensive, it was applied exclusively at the design and tuning stage of the composite technique, and so perceptual considerations are embedded into the resulting solution, though no VDP calculations were performed during lighting simulation. The proposed illumination technique is also novel, providing intermediate image solutions of high quality at unprecedented speeds, even for complex scenes. One advantage of the technique is that local estimates of global illumination are readily available at the early stages of computing, making possible the development of a more robust adaptive mesh subdivision, which is guided by local contrast information. Efficient object space filtering, also based on stochastically-derived estimates of the local illumination error, is applied to substantially reduce the visible noise inherent in stochastic solutions.
On the Validity of the Maximum Principle and of the Euler--Lagrange Equation for a Minimum Problem Depending on the Gradient
Authors: Arrigo Cellina, Stefania Perrotta
Venue: SIAM Journal on Control and Optimization (1998)

We consider the limiting case $\alpha =\infty$ of the problem of minimizing $$ \int_\Omega (\|\nabla u(x)\|^{\alpha} + g(u)) dx \hbox { on $u \in u_0 + W^{1,\alpha}_0(\Omega )$}, $$ where g is differentiable and strictly monotone. If this infimum is finite, it is evidently attained; we show that any minimizing function u satisfies the appropriate form of the Euler--Lagrange equation, i.e., for some function p, $$ \div \, p(x) = g'(u(x)) \quad{\rm for}\quad p(x) \in \partial j_B(\nabla u(x)), $$ where jB is the indicator function of the closed unit ball in the Euclidean norm of ${\Bbb R}^N$ and $\partial$ is the subdifferential of the convex function jB.
Walk-Time Address Adjustment for Improving the Accuracy of Dynamic Branch Prediction
Authors: Chien-Ming Chen, Chung-Ta King
Venue: IEEE Transactions on Computers (1999)

Dynamic branch prediction has been an effective technique for boosting the performance of modern high performance microprocessors. Since hardware predictors only have a limited number of 2-bit counters but programs often have a large, variable number of branches, two branches in the programs may thus be mapped to the same 2-bit counter. Predictions for these two branches may interfere with each other. This, in turn, reduces the prediction accuracy. In this paper, we discuss how a pre-run-time optimization technique, called address adjustment, can help to reduce branch interference. The technique adjusts the addresses of conditional branches in the given program by inserting NOP instructions at appropriate locations. In this way, the mapping between the conditional branches and the 2-bit counters can be controlled and branch interference can be minimized. Address adjustment can be applied at compile or link time, and the latter makes it a walk-time transformation technique [4]. Three possible address adjustment schemes are investigated: constrained address adjustment, relaxed address adjustment, and branch classification. Experimental results show that address adjustment can reduce branch misprediction ratios on existing hardware predictors. Among the three methods, branch classification has the most improvement.
SQLEM: fast clustering in SQL using the EM algorithm
Authors: Carlos Ordonez, Paul Cereghini
Venue: ACM SIGMOD Record (2000)

Clustering is one of the most important tasks performed in Data Mining applications. This paper presents an efficient SQL implementation of the EM algorithm to perform clustering in very large databases. Our version can effectively handle high dimensional data, a high number of clusters and more importantly, a very large number of data records. We present three strategies to implement EM in SQL: horizontal, vertical and a hybrid one. We expect this work to be useful for data mining programmers and users who want to cluster large data sets inside a relational DBMS.
Robots with a gentle touch: advances in assistive robotics and prosthetics
Authors: W. S. Harwin
Venue: Technology and Health Care (1999)

As healthcare costs rise and an aging population makes an increased demand on services, so new techniques must be introduced to promote an individuals independence and provide these services. Robots can now be designed so they can alter their dynamic properties changing from stiff to flaccid, or from giving no resistance to movement, to damping any large and sudden movements. This has some strong implications in health care in particular for rehabilitation where a robot must work in conjunction with an individual, and might guiding or assist a persons arm movements, or might be commanded to perform some set of autonomous actions. This paper presents the state-of-the-art of rehabilitation robots with examples from prosthetics, aids for daily living and physiotherapy. In all these situations there is the potential for the interaction to be non-passive with a resulting potential for the human/machine/environment combination to become unstable. To understand this instability we must develop better models of the human motor system and fit these models with realistic parameters. This paper concludes with a discussion of this problem and overviews some human models that can be used to facilitate the design of the human/machine interfaces.
Online association rule mining
Authors: Christian Hidber
Venue: ACM SIGMOD Record (1999)

We present a novel algorithm to compute large itemsets online. The user is free to change the support threshold any time during the first scan of the transaction sequence. The algorithm maintains a superset of all large itemsets and for each itemset a shrinking, deterministic interval on its support. After at most 2 scans the algorithm terminates with the precise support for each large itemset. Typically our algorithm is by an order of magnitude more memory efficient than Apriori or DIC.
Mutual disambiguation of recognition errors in a multimodel architecture
Authors: Sharon Oviatt
Venue: Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit (1999)

As a new generation of multimodal/media systems begins to define itself, researchers are attempting to learn how to combine different modes into strategically integrated whole systems. In theory, well designed multimodal systems should be able to integrate complementary modalities in a manner that supports mutual disambiguation (MD) of errors and leads to more robust performance. In this study, over 2,000 multimodal utterances by both native and accented speakers of English were processed by a multimodal system, and then logged and analyzed. The results confirmed that multimodal systems can indeed support significant levels of MD, and also higher levels of MD for the more challenging accented users. As a result, although speech recognition as a stand-alone performed far more poorly for accented speakers, their multimodal recognition rates did not differ from those of native speakers. Implications are discussed for the development of future multimodal architectures that can perform in a more robust and stable manner than individual recognition technologies. Also discussed is the design of interfaces that support diversity in tangible ways, and that function well under challenging real-world usage conditions,
Transformation of Families of Matrices to Normal Forms and its Application to Stability Theory
Authors: Alexei A. Mailybaev
Venue: SIAM Journal on Matrix Analysis and Applications (1999)

Families of matrices smoothly depending on a vector of parameters are considered. Arnold [Russian Math. Surveys, 26 (1971), pp. 29--43] and Galin [ Uspekhi Mat. Nauk, 27 (1972), pp. 241--242] have found and listed normal forms of families of complex and real matrices (miniversal deformations), to which any family of matrices can be transformed in the vicinity of a point in the parameter space by a change of basis, smoothly dependent on a vector of parameters, and by a smooth change of parameters. In this paper a constructive method of determining functions describing a change of basis and a change of parameters, transforming an arbitrary family to the miniversal deformation, is suggested. Derivatives of these functions with respect to parameters are determined from a recurrent procedure using derivatives of the functions of lower orders and derivatives of the family of matrices. Then the functions are found as Taylor series. Examples are given. The suggested method allows using efficiently miniversal deformations for investigation of different properties of matrix families. This is shown in the paper where tangent cones (linear approximations) to the stability domain at the singular boundary points are found.
Minimax Control of Parabolic Systems with State Constraints
Authors: Nadir Arada, Jean-Pierre Raymond
Venue: SIAM Journal on Control and Optimization (1999)

In this paper we study a minimax control problem for parabolic equations in the presence of pointwise state constraints. The terminology minimax here refers to a cost functional defined with a $L^{\infty}$-norm. The directional derivatives of the $L^{\infty}$-norm are elements of $(L^{\infty})'$. Therefore, the adjoint equation may involve finitely additive measures in place of Radon measures. To overcome this difficulty, we introduce a compactification (of Stone--\u{C}ech type). We prove necessary optimality conditions which are new, both in the case with no state constraints and in the case with state constraints. Under some convexity conditions, these optimality conditions are also sufficient.
Caveat emptor&excl;
Authors: Audrey Biloon
Venue: International Journal of Network Management (1999)

A standard contract &lpar;one printed on a standard form, with standard language&rpar; can be changed or fully rewritten to meet your company&apos;s specific needs. Buying equipment without a contract that meets your company&apos;s specific needs and that is drafted or reviewed by legal counsel &lpar;specifically a lawyer who knows your company&apos;s needs well&rpar; is the equivalent of buying a potential lawsuit. Prevention of problems with a good contract and legal help is your company&apos;s best insurance against waste and&sol;or litigation. Copyright &copy; 1999 John Wiley Sons, Ltd.
Absolute Stabilization and Minimax Optimal Control of Uncertain Systems with Stochastic Uncertainty
Authors: V. A. Ugrinovskii, I. R. Petersen
Venue: SIAM Journal on Control and Optimization (1999)

This paper is concerned with existence and optimality properties of so-called guaranteed cost controllers for an uncertain system subject to structured uncertainty. The uncertainty in the system is assumed to have a stochastic character and to satisfy certain stochastic integral constraints. It is shown that a minimax optimal guaranteed cost state feedback controller for a stochastic system can be synthesized as a state feedback controller absolutely stabilizing this system. For each initial state of the system, this controller can be found by parametric optimization of solutions of a parameter-dependent generalized matrix Riccati equation arising in stochastic $H_\infty$ theory.
2001 (Invited talk. Abstract only): a statistical odyssey
Authors: Daryl Pregibon
Venue: Proceedings of the fifth ACM SIGKDD international conference on Knowledge discovery and data mining (1999)

This talk is an interim report on the 5 year plan launched in 1996 to provide a theoretical and computational foundation of Statistics for massive data sets. The plan coincided with the formation of AT T Labs and the proposed research agenda of the InfoLab, which is both a physical laboratory and an interdisciplinary collection of information researchers in CS, mathematics, and Statistics. At the halfway point of this odyssey we can identify some success stories but more importantly it is an opportune time to re-calibrate the challenges and the milestones.
New tiling techniques to improve cache temporal locality
Authors: Yonghong Song, Zhiyuan Li
Venue: ACM SIGPLAN Notices (1999)

Tiling is a well-known loop transformation to improve temporal locality of nested loops. Current compiler algorithms for tiling are limited to loops which are perfectly nested or can be transformed, in trivial ways, into a perfect nest. This paper presents a number of program transformations to enable tiling for a class of nontrivial imperfectly-nested loops such that cache locality is improved. We define a program model for such loops and develop compiler algorithms for their tiling. We propose to adopt odd-even variable duplication to break anti- and output dependences without unduly increasing the working-set size, and to adopt speculative execution to enable tiling of loops which may terminate prematurely due to, e.g. convergence tests in iterative algorithms. We have implemented these techniques in a research compiler, Panorama. Initial experiments with several benchmark programs are performed on SGI workstations based on MIPS R5K and R10K processors. Overall, the transformed programs run faster by 9% to 164%.