Systems and Networking
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On design principles for a molecular computer
If the unique information-processing capabilities of protein enzymes could be adapted for computers, then evolvable, more efficient systems for such applications as pattern recognition and process control are in principle possible.
Computing in the home: shifts in the time allocation patterns of households
An empirical study of 282 users of home computers was conducted to explore the relationship between computer use and shifts in time allocation patterns in the household. Major changes in time allocated to various activities were detected. Prior experience with computers (i.e., prior to purchase of the home computer) was found to have a significant impact on the time allocation patterns in the household. The study provides evidence that significant behavior changes can occur when people adopt personal computers in their homes.
As computers become more powerful and sophisticated, computational astrophysicists will be able to find out more about stellar evolution and other astronomical phenomena.
A class of sorting algorithms based on Quicksort
Bsort, a variation of Quicksort, combines the interchange technique used in Bubble sort with the Quicksort algorithm to improve the average behavior of Quicksort and eliminate the worst case situation of O(n2) comparisons for sorted or nearly sorted lists. Bsort works best for nearly sorted lists or nearly sorted in reverse.
Statistical mechanics and disordered systems
Since computers are able to simulate the equilibrium properties of model systems, they may also prove useful for solving the hard optimization problems that arise in the engineering of complex systems.
Special-purpose processors in theoretical physics
Specially designed processors can provide a method for attacking some of the difficult computational problems facing theoretical physicists.
Symbolic mathematical computation
Standard programming languages are inadequate for the kind of symbolic mathematical computations that theoretical physicists need to perform. Higher mathematics systems like SMP address this problem.
Monte Carlo methods in theoretical high-energy physics
Although lattice field theorists have been able to develop new approaches to the Monte Carlo method and to successfully apply them in Bosonic calculations, faster and larger computers are needed for Fermion-field evaluations.
Experimental mathematics: the role of computation in nonlinear science
Computers have expanded the range of nonlinear phenomena that can be explored mathematically. An “experimental mathematics facility,” containing both special-purpose dedicated machines and general-purpose mainframes, may someday provide the ideal context for complex nonlinear problems.
A generalized implicit enumeration algorithm for graph coloring
A generalized algorithm for graph coloring by implicit enumeration is formulated. A number of backtracking sequential methods are discussed in terms of the generalized algorithm. Some are revealed to be partially correct and inexact. A few corrections to the invalid algorithms, which cause these algorithms to guarantee optimal solutions, are proposed. Finally, some computational results and remarks on the practical relevance of improved implicit enumeration algorithms are given.
Amortized analyses of self-organizing sequential search heuristics
The performance of sequential search can be enhanced by the use of heuristics that move elements closer to the front of the list as they are found. Previous analyses have characterized the performance of such heuristics probabilistically. In this article, we use amortization to analyze the heuristics in a worst-case sense; the relative merit of the heuristics in this analysis is different in the probabilistic analyses. Experiments show that the behavior of the heuristics on real data is more closely described by the amortized analyses than by the probabilistic analyses.
Designing for usability: key principles and what designers think
This article is both theoretical and empirical. Theoretically, it describes three principles of system design which we believe must be followed to produce a useful and easy to use computer system. These principles are: early and continual focus on users; empirical measurement of usage; and iterative design whereby the system (simulated, prototype, and real) is modified, tested, modified again, tested again, and the cycle is repeated again and again. This approach is contrasted to other principled design approaches, for example, get it right the first time, reliance on design guidelines. Empirically, the article presents data which show that our design principles are not always intuitive to designers; identifies the arguments which designers often offer for not using these principles—and answers them; and provides an example in which our principles have been used successfully.
Pricing computer services: queueing effects
This article studies the effects of queueing delays, and users' related costs, on the management and control of computing resources. It offers a methodology for setting price, utilization, and capacity, taking into account the value of users' time, and it examines the implications of alternative control structures, determined by the financial responsibility assigned to the data processing manager.
Computer science in secondary schools: curriculum and teacher certification
Computer science in secondary schools is an area of increasing interest and concern to educators as well as to computer science professionals. Each of the next two reports addresses an issue of major importance regarding computer science in secondary schools. The first report recommends computer science courses for the secondary school curriculum, and the second report recommends requirements for teacher certification in computer science.In 1983 the ACM Education Board initiated efforts to formulate recommendations for secondary school computer science. Two task forces, one for curriculum recommendations and the other for teacher certification recommendations, were established under the Education Board's Elementary and Secondary Schools Subcommittee. The work of the two task forces was also supported by the IEEE Computer Society Educational Activities Board, and the final reports from the task forces were jointly approved by the ACM and IEEE-CS boards in July 1984. Thus the reports are significan't not only for the important issues that they address, but also because they represent a joint activity between ACM and the IEEE Computer Society.The work of the two task forces is summarized in the next two reports. The full reports are available as the publication Computer Science in Secondary Schools: Curriculum and Teacher Certification, Order Number 201850, from the ACM Order Department, P.O. Box 64145, Baltimore, MD 21264.
An evaluation of retrieval effectiveness for a full-text document-retrieval system
An evaluation of a large, operational full-text document-retrieval system (containing roughly 350,000 pages of text) shows the system to be retrieving less than 20 percent of the documents relevant to a particular search. The findings are discussed in terms of the theory and practice of full-text document retrieval.
Predicting performance in an introductory computer science course
A group of 269 first-semester freshmen was used to predict both performance in an introductory computer science course and first-semester college grade point average by using information regarding the students' programs and performance in high school along with American College Testing Program (ACT) test scores.
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