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Association for Computing Machinery

Articles Tagged: Measurement

Articles & Features

Use of motion field warping to generate cardiac images

In this study, we developed an algorithmic method to analyze late contrast-enhanced (CE) magnetic resonance (MR) images, revealing the so-called hibernating myocardium. The algorithm is based on an efficient and robust image registration algorithm. Using our method, we are able to integrate the static late CE MR image with its corresponding cardiac cine MR images, constructing cardiac motion CE MR images, which are referred to as cardiac cine CE MR images. This method appears promising as an improved cardiac viability assessment tool

By Gang Gao, Paul Cockshott, September 2007

PDF | HTML | In the Digital Library

Prefix compression of sparse binary strings

Note from ACM Crossroads: Due to errors in the layout process for printing on paper, the version of this article in the printed magazine contained several errors (mostly related to superscripts). This HTML version is the accurate version. Please refer to this HTML version instead of the printed version and accept our apologies for any inconvenience.

By David Salomon, March 2000

PDF | HTML | In the Digital Library

The Texas Tech tornado cluster

By Per Andersen, September 1999

PDF | HTML | In the Digital Library

Parallel processing in heterogeneous cluster architechtures using JavaPorts

By Demetris G. Galatopoullos, Elias S. Manolakos, March 1999

PDF | HTML | In the Digital Library

The Damocles Sword of Academic Publishing

Doctoral students often find it hard to understand at what level of productivity they should be. Through an analysis of resums of doctoral students in the Management Information Systems (MIS) field, a better understanding of what is expected of current students as compared to former students is achieved. Both conference presentations and publications in journals are examined. Finally, there is an examination of whether the quantity of publications can be related to the ranking of the school that a student attends.

By Kai Larsen, November 1998

PDF | HTML | In the Digital Library


Robotic soccer is a challenging research domain involving multiple agents that need to collaborate in an adversarial environment to achieve specific objectives. This article describes CMUnited, the team of small robotic agents that we developed to enter the RoboCup-97 competition. We designed and built the robotic agents, devised the appropriate vision algorithm, and developed and implemented algorithms for strategic collaboration between the robots in an uncertain and dynamic environment. The robots can organize themselves in formations, hold specific roles, and pursue their goals. In game situations, they have demonstrated their collaborative behaviors on multiple occasions. The robots can also switch roles to maximize the overall performance of the team. We present an overview of the vision processing algorithm which successfully tracks multiple moving objects and predicts trajectories. The paper then focuses on the agents' behaviors ranging from low-level individual behaviors to coordinated, strategic team behaviors. CMUnited won the RoboCup-97 small-robot competition at IJCAI-97 in Nagoya, Japan.

By Manuela Veloso, Peter Stone, Kwun Han, Sorin Achim, April 1998

PDF | HTML | In the Digital Library

A human's eye view

Frameless Rendering (FR) is a rendering paradigm which performs stochastic temporal filtering by updating pixels in a random order, based on most recent available input data, and displaying them to the screen immediately [1]. This is a departure from frame-based approaches commonly experienced in interactive graphics. A typical interactive graphics session uses a single input state to compute an entire frame. This constrains the state to be known at the time the first pixel's value is computed. Frameless Rendering samples inputs many times during the interval which begins at the start of the first pixel's computation and ends with the last pixel's computation. Thus, Frameless Rendering performs temporal supersampling - it uses more samples over time. This results in an approximation to motion blur, both theoretically and perceptually.This paper explores this motion blur and its relationship to: camera open shutter time, current computer graphics motion-blur implementations, temporally anti-aliased images, and the Human Visual System's (HVS) motion smear quality (see 'quality' footnote) [2].Finally, we integrate existing research results to conjecture how Frameless Rendering can use knowledge of the Human Visual System's blurred retinal image to direct spatiotemporal sampling. In other words, we suggest importance sampling (see 'sampling' footnote) by prioritizing pixels for computation based on their importance to the visual system in discerning what is occurring in an interactive image sequence.

By Ellen J. Scher Zagier, May 1997

PDF | HTML | In the Digital Library

Reasoning about computational resource allocation

Anytime Algorithms are algorithms that exchange execution time for quality of results. Since many computational tasks are too complicated to be completed at real-time speeds, anytime algorithms allow systems to intelligently allocate computational time resources in the most effective way, depending on the current environment and the system's goals. This article briefly covers the motivations for creating anytime algorithms, the history of their development, a definition of anytime algorithms, and current research involving anytime algorithms.

By Joshua Grass, September 1996

PDF | HTML | In the Digital Library

Dependency diagrams

A method of illustrating program structure by showing how sections depend on each other is presented. This suggests an intuitive metric for program partitioning, which is developed with supporting theory.

By Mark Ray, February 1996

PDF | HTML | In the Digital Library