Results 1  10
of
85
Register Allocation via Graph Coloring
, 1992
"... Chaitin and his colleagues at IBM in Yorktown Heights built the first global register allocator based on graph coloring. This thesis describes a series of improvements and extensions to the Yorktown allocator. There are four primary results: Optimistic coloring Chaitin's coloring heuristic pessimis ..."
Abstract

Cited by 135 (4 self)
 Add to MetaCart
Chaitin and his colleagues at IBM in Yorktown Heights built the first global register allocator based on graph coloring. This thesis describes a series of improvements and extensions to the Yorktown allocator. There are four primary results: Optimistic coloring Chaitin's coloring heuristic pessimistically assumes any node of high degree will not be colored and must therefore be spilled. By optimistically assuming that nodes of high degree will receive colors, I often achieve lower spill costs and faster code; my results are never worse. Coloring pairs The pessimism of Chaitin's coloring heuristic is emphasized when trying to color register pairs. My heuristic handles pairs as a natural consequence of its optimism. Rematerialization Chaitin et al. introduced the idea of rematerialization to avoid the expense of spilling and reloading certain simple values. By propagating rematerialization information around the SSA graph using a simple variation of Wegman and Zadeck's constant propag...
On the Dynamics and Significance of Low Frequency Components of Internet Load
 Internetworking: Research and Experience
, 1992
"... Dynamics of Internet load are investigated using statistics of roundtrip delays, packet losses and outoforder sequence of acknowledgments. Several segments of the Internet are studied. They include a regional network (the Jon yon Neumann Center Network), a segment of the NSFNet backbone and a cro ..."
Abstract

Cited by 84 (0 self)
 Add to MetaCart
Dynamics of Internet load are investigated using statistics of roundtrip delays, packet losses and outoforder sequence of acknowledgments. Several segments of the Internet are studied. They include a regional network (the Jon yon Neumann Center Network), a segment of the NSFNet backbone and a crosscountry network consisting of regional and backbone segments.
Grand Tour and Projection Pursuit
 Journal of Computational and Graphical Statistics
, 1995
"... The grand tour and projection pursuit are two methods for exploring multivariate data. We show how to combine them into a dynamic graphical tool for exploratory data analysis, called a projection pursuit guided tour. This tool assists in clustering data when clusters are oddly shaped and in finding ..."
Abstract

Cited by 65 (19 self)
 Add to MetaCart
The grand tour and projection pursuit are two methods for exploring multivariate data. We show how to combine them into a dynamic graphical tool for exploratory data analysis, called a projection pursuit guided tour. This tool assists in clustering data when clusters are oddly shaped and in finding general lowdimensional structure in high dimensional, and in particular, sparse data. An example shows that the method, which is projectionbased, can be quite powerful in situations which may cause methods based on kernelsmoothing grief. The projection pursuit guided tour is also useful for comparing and developing projection pursuit indices and illustrating some types of asymptotic results. 1 Introduction In this paper we show that two graphical methods for exploring high (say p) dimensional data, the grand tour (Asimov, 1985; Buja and Asimov, 1986), a dynamic tool, and projection pursuit (Kruskal, 1969; Friedman and Tukey, 1974; Huber, 1985), a static tool, naturally complement each o...
Autonomous selfassembly in swarmbots
 IEEE Trans. Robot
, 2006
"... Summary. Multirobot systems have been studied in tasks that require the robots to be physically linked. In such a configuration, a group of robots may navigate a terrain that proves too difficult for a single robot. On the contrary, many collective tasks can be accomplished more efficiently by a gr ..."
Abstract

Cited by 64 (33 self)
 Add to MetaCart
Summary. Multirobot systems have been studied in tasks that require the robots to be physically linked. In such a configuration, a group of robots may navigate a terrain that proves too difficult for a single robot. On the contrary, many collective tasks can be accomplished more efficiently by a group of independent robots. This paper is about swarmbot, a robotic system that can operate in both configurations and autonomously switch from one to the other. We examine the performance of a single robot and of groups of robots selfassembling with an object or another robot. We assess the robustness of the system with respect to different types of rough terrain. Finally, we evaluate the performance of swarms of 16 physical robots. At present, for selfassembly in autonomous, mobile robotics, swarmhots is the state of the art for what concerns reliability, robustness and speed.
GGobi: Evolving from XGobi into an Extensible Framework for Interactive Data Visualization
, 2006
"... GGobi is a direct descendent of a data visualization system called XGobi that has been around since the early 1990’s. GGobi’s new features include multiple plotting windows, a color lookup table manager, and an XML (Extensible Markup Language) file format for data. Perhaps the biggest advance is tha ..."
Abstract

Cited by 43 (10 self)
 Add to MetaCart
GGobi is a direct descendent of a data visualization system called XGobi that has been around since the early 1990’s. GGobi’s new features include multiple plotting windows, a color lookup table manager, and an XML (Extensible Markup Language) file format for data. Perhaps the biggest advance is that GGobi can be easily extended, either by being embedded in other software or by the addition of plugins; either way, it can be controlled using an API (Application Programming Interface). An illustration of its extensibility is that it can be embedded in R. The result is a full marriage between GGobi’s direct manipulation graphical environment and R’s familiar extensible environment for statistical data analysis.
Feature Detection in Linked Derived Spaces
 in Proceedings of the IEEE Visualization 1998
"... This paper describes by example a strategy for plotting and interacting with data in multiple metric spaces. The example system was designed for use with timevarying computational fluid dynamics (CFD) datasets, but the methodology is directly applicable to other types of field data. The central obj ..."
Abstract

Cited by 33 (1 self)
 Add to MetaCart
This paper describes by example a strategy for plotting and interacting with data in multiple metric spaces. The example system was designed for use with timevarying computational fluid dynamics (CFD) datasets, but the methodology is directly applicable to other types of field data. The central objects embodied by the tool are portraits, which show the data in various coordinate systems, while preserving their spatial connectivity and temporal variability. The coordinates are derived in various ways from the field data, and an important feature is that new and derived portraits can be created interactively. The primary operations supported by the tool are brushing and linking: the user can select a subset of a given portrait, and this subset is highlighted in all portraits. The user can combine highlighted subsets from an arbitrary number of portraits with the usual logical operators, thereby indicating where an arbitrarily complex set of conditions holds. The system is useful for ex...
Bayesian Treed Models
 Machine Learning
, 2000
"... When simple parametric models such as linear regression fail to adequately approximate a function across an entire set of data, an alternative may be to consider a partition of the data, and then use a separate simple model within each subset of the partition. Such an alternative is provided by ..."
Abstract

Cited by 32 (1 self)
 Add to MetaCart
When simple parametric models such as linear regression fail to adequately approximate a function across an entire set of data, an alternative may be to consider a partition of the data, and then use a separate simple model within each subset of the partition. Such an alternative is provided by a treed model which uses a binary tree to identify such a partition. However, treed models go further than conventional trees (eg CART, C4.5) by tting models rather than simple means or proportions across the partition. In this paper, we propose a Bayesian approach for nding and tting parametric treed models, in particular focusing on Bayesian treed regression. The potential of this approach is illustrated by a crossvalidation comparison of predictive performance with neural nets, MARS, and conventional trees on simulated and real data sets. Keywords: binary trees, Markov chain Monte Carlo, model selection, stochastic search. 1 Hugh Chipman is Associate Professor of Statistics...
Simultaneous NonParametric Regressions of Unbalanced Longitudinal Data
, 1997
"... : The aim of this paper is to simultaneously estimate n curves corrupted by noise it means several observations of a random process. The non parametric estimation of the sampled paths leads to a new kind of functional principal components analysis when simultaneously takes into account a dimensional ..."
Abstract

Cited by 27 (10 self)
 Add to MetaCart
: The aim of this paper is to simultaneously estimate n curves corrupted by noise it means several observations of a random process. The non parametric estimation of the sampled paths leads to a new kind of functional principal components analysis when simultaneously takes into account a dimensionality and a smoothness constraint. Furthermore, the use of Bsplines approximations to estimate the curves allows the study of unbalanced longitudinal data. The relationship between the choice of the smoothing parameter and that of dimensionality is discussed. A simulation study shows good behaviors of this proposed estimate compared to n independent smoothing splines under generalized cross validation. Finally, the methodology of this paper is illustrated by its application to a real world data set. Keywords: Nonparametric regression, functional principal component analysis, hybrid splines, Bsplines, rainfall data. 1 Introduction The aim of this paper is the functional estimation of severa...
Distributed Performance Monitoring: Methods, Tools and Applications
 IEEE Transactions on Parallel and Distributed Systems
, 1994
"... A method for analyzing the functional behavior and the performance of programs in distributed systems is presented. We use hybrid monitoring, a technique which combines advantages of both software monitoring and hardware monitoring. The paper contains a description of a hardware monitor and a softwa ..."
Abstract

Cited by 22 (4 self)
 Add to MetaCart
A method for analyzing the functional behavior and the performance of programs in distributed systems is presented. We use hybrid monitoring, a technique which combines advantages of both software monitoring and hardware monitoring. The paper contains a description of a hardware monitor and a software package (ZM4/SIMPLE) which make our concepts available to programmers, assisting them in debugging and tuning of their code. A short survey of related monitor systems highlights the distinguishing features of our implementation. As an application of our monitoring and evaluation system, the analysis of a parallel ray tracing program running on the SUPRENUM multiprocessor is described. It is shown that monitoring and modeling both rely on a common abstraction of a system's dynamic behavior and therefore can be integrated to one comprehensive methodology. This methodology is supported by a set of tools. Keywords (Index Terms, Key Phrases): hardware monitoring, hybrid monitoring, eventdri...
Approximation Spline De La Prévision D'un Processus Fonctionnel Autorégressif D'ordre 1
, 1996
"... We present a method to approximate and forecast, on an entire interval, a continuous time process. For this purpose, we use the modelization of ARH(1) processes, defined by Bosq (1991). We deal with the practical problem of the discretization of the observed trajectories and approximate them by mean ..."
Abstract

Cited by 21 (4 self)
 Add to MetaCart
We present a method to approximate and forecast, on an entire interval, a continuous time process. For this purpose, we use the modelization of ARH(1) processes, defined by Bosq (1991). We deal with the practical problem of the discretization of the observed trajectories and approximate them by means of splines functions. We show by simulations that for "well chosen" smoothing parameters, good prediction can be obtained compared to the "predictable" part of the process. Finally, we apply this model to forecast road traffic and compare it to a SARIMA model. Key words : functional prediction, ARH(1) process, smoothing spline, principal component analysis. AMS 1991 subject classification : 62H25, 62G07, 62M20: 1 Introduction Cet article s'int'eresse `a la pr'evision d'un processus pr'esentant naturellement une composante p'eriodique. C'est le cas des donn'ees 'etudi'ees dans la section 5, issues de l'observation du trafic horaire autoroutier `a un poste de p'eage. On se propose de pr'ev...