A study of computational aspects of network models for planning and control

Beginning with the PERT-CPM methodology and progressing through the more general network models, this study critically reviews the computational assumptions, results and possible errors, both by character and magnitude

NASA Lewis Research Center Futuring Workshop

On October 21 and 22, 1986, the Futures Group ran a two-day Futuring Workshop on the premises of NASA Lewis Research Center. The workshop had four main goals: to acquaint participants with the general history of technology forecasting; to familiarize participants with the range of forecasting methodologies; to acquaint participants with the range of applicability, strengths, and limitations of each method; and to offer participants some hands-on experience by working through both judgmental and quantitative case studies. Among the topics addressed during this workshop were: information sources; judgmental techniques; quantitative techniques; merger of judgment with quantitative measurement; data collection methods; and dealing with uncertainty

The ingenuity of common workmen: and the invention of the computer

Since World War II, state support for scientific research has been assumed crucial to technological and economic progress. Governments accordingly spent tremendous sums to that end. Nothing epitomizes the alleged fruits of that involvement better than the electronic digital computer. The first such computer has been widely reputed to be the ENIAC, financed by the U.S. Army for the war but finished afterwards. Vastly improved computers followed, initially paid for in good share by the Federal Government of the United States, but with the private sector then dominating, both in development and use, and computers are of major significance.;Despite the supposed success of public-supported science, evidence is that computers would have evolved much the same without it but at less expense. Indeed, the foundations of modern computer theory and technology were articulated before World War II, both as a tool of applied mathematics and for information processing, and the computer was itself on the cusp of reality. Contrary to popular understanding, the ENIAC actually represented a movement backwards and a dead end.;Rather, modern computation derived more directly, for example, from the prewar work of John Vincent Atanasoff and Clifford Berry, a physics professor and graduate student, respectively, at Iowa State College (now University) in Ames, Iowa. They built the Atanasoff Berry Computer (ABC), which, although special purpose and inexpensive, heralded the efficient and elegant design of modern computers. Moreover, while no one foresaw commercialization of computers based on the ungainly and costly ENIAC, the commercial possibilities of the ABC were immediately evident, although unrealized due to war. Evidence indicates, furthermore, that the private sector was willing and able to develop computers beyond the ABC and could have done so more effectively than government, to the most sophisticated machines.;A full and inclusive history of computers suggests that Adam Smith, the eighteenth century Scottish philosopher, had it right. He believed that minimal and aloof government best served society, and that the inherent genius of citizens was itself enough to ensure the general prosperity

Design and implementation of a language for manipulating algebraic formulae

This thesis explores the possibilities of doing mathematical problems involving algebra on a computer. A language is designed which allows names to occur as unknown quantities. This language has all the facilities of a general purpose language such as IMP, but is designed to be used inter-actively by a user at a console. The language also includes instructions which cause the usual algebraic operations to be applied to expressions. These operators include simplification, differentiation, but not integration. A brief survey is given of other languages in the field, with comments on their capabilities and restrictions. The second part of the thesis describes how the language is implemented. An interpreter is used. Statements of the language are analysed syntactically and then obeyed. Algebraic expressions are stored in byte arrays, using a type of prefix Polish notation. Finally the language is reviewed in the light of recent work done in the field, and suggestions are made for a further version

The 1988 Goddard Conference on Space Applications of Artificial Intelligence

This publication comprises the papers presented at the 1988 Goddard Conference on Space Applications of Artificial Intelligence held at the NASA/Goddard Space Flight Center, Greenbelt, Maryland on May 24, 1988. The purpose of this annual conference is to provide a forum in which current research and development directed at space applications of artificial intelligence can be presented and discussed. The papers in these proceedings fall into the following areas: mission operations support, planning and scheduling; fault isolation/diagnosis; image processing and machine vision; data management; modeling and simulation; and development tools/methodologies

The association of working memory and anxiety with skill acquisition and transfer in young and older adults

Two studies, involving a total of 184 adults between 17 and 89 years of age, were conducted to determine whether age differences in skill acquisition and transfer could be related to age differences in working memory functioning and anxiety. In both experiments, working memory functioning was measured using the Digit Span task (Wechsler, 1997) und the Reading Span tusk (Daneman & Carpenter, 1980), while anxiety levels were measured using the State Trait Anxiety Inventory (Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983). Participants were required to perform a mental arithmetic task in Experiment I, and a visual numerosity task in Experiment 2. In each experiment, participants received 240 trials of the task during u training phase (in which one set of stimuli were used) and 240 trials during a transfer phase (in which a second set of stimuli were used). The results from both studies revealed that partial positive transfer occurred from one phase to another for both young and older adults. This indicates that both age groups learned the skills in a similar way: using a combination of general und specific learning, Moreover, the older adults in both experiments became faster with practice, they generally improved as much as younger adults with practice, and they were able to achieve the same or better levels of accuracy compared to younger adults, This suggests that healthy older adults possess the ability to learn new skills. When scores for working memory span and anxiety were analysed, working memory span was found to correlate significantly with the accuracy levels and reaction times of the young age group in Experiment l, and of both age groups in Experiment 2. Similarly, anxiety levels were related to reaction times for both age groups in both experiments, with higher levels of anxiety also associated with smaller working memory spans for the young adults in both experiments. These results suggest that both working memory span and anxiety hove an impact on the performance of participants, and can account for some of the age differences observed during skill acquisition and transfer