81,617 research outputs found
Reordering computations for parallel execution
The computations are reordered in the SOR algorithm to maintain the same asymptotic rate of convergence as the rowwise ordering to obtain parallelism at different levels. A parallel program is written to illustrate these ideas and actual machines for implementation of this program are discussed
An M-step preconditioned conjugate gradient method for parallel computation
This paper describes a preconditioned conjugate gradient method that can be effectively implemented on both vector machines and parallel arrays to solve sparse symmetric and positive definite systems of linear equations. The implementation on the CYBER 203/205 and on the Finite Element Machine is discussed and results obtained using the method on these machines are given
M-step preconditioned conjugate gradient methods
Preconditioned conjugate gradient methods for solving sparse symmetric and positive finite systems of linear equations are described. Necessary and sufficient conditions are given for when these preconditioners can be used and an analysis of their effectiveness is given. Efficient computer implementations of these methods are discussed and results on the CYBER 203 and the Finite Element Machine under construction at NASA Langley Research Center are included
Active control and system identification of rotordynamic structure
Four current research projects are summarized: (1) active control of rotor system dynamics; (2) attenuation of rotor vibration using controlled pressure hydrostatic bearings; (3) a new seal test facility for measuring isotropic and anisotropic linear rotordynamic characteristics; and (4) the use of rotordynamic instability thresholds to accurately measure bearing rotordynamic characteristics
Reform of Preservice Science Education: An Example from a State-Supported University
The ongoing movement to reform the teaching and learning of mathematics and science began as an effort targeting grades K-12. This movement, however, also has significant implications for institutions of higher education, especially in the area of teacher preparation. Northeast Louisiana University has utilized an extensive system of support, including vital National Science Foundation funding, to redesign its science curriculum for elementary education majors. Four courses featuring the content areas of biology, chemistry, geosciences, and physics and integrated with respect to content and methodology were collaboratively developed by education and science faculty. and were approved as requirements for all preservice majors. Preliminary evaluation results with respect to students’ content knowledge and attitude are favorable. Ongoing efforts include the development of activities designed to further integrate the courses with respect to content and the execution of focused evaluative studies to reflect the degree of implementation of the reform practices that have been modeled by the university faculty
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Questionnaires, in-depth interviews and focus groups
With fast changing technologies and related human interaction issues, there is an increased need for timely evaluation of systems with distributed users in varying contexts (Pace, 2004). This has led to the increased use of questionnaires, in-depth interviews and focus groups in commercial usability and academic research contexts. Questionnaires are usually paper based or delivered online and consist of a set of questions which all participants are asked to complete. Once the questionnaire has been created, it can be delivered to a large number of participants with little effort. However, a large number of participants also means a large amount of data needing to be coded and analysed. Interviews, on the other hand, are usually conducted on a one-to-one basis. They require a large amount of the investigator’s time during the interviews and also for transcribing and coding the data. Focus groups usually consist of one investigator and a number of participants in any one session. Although the views of any one participant cannot be probed to same degree as in an interview, the discussions that are facilitated within the groups often result in useful data in a shorter space of time than that required by one-to-one interviews.
All too often, however, researchers eager to identify usability problems quickly throw together a questionnaire, interview or focus group that, when analysed, produces very little of interest. What is often lacking is an understanding of how the research method design fits with the research questions (Creswell, 2003) and how to appropriately utilise these different approaches for specific HCI needs. The methods described in this chapter can be useful when used alone but are most useful when used together with other methods. Creswell (2003) provides a comprehensive analysis of the different quantitative and qualitative methods and howthey can be mixed and matched for overall better quality research. Depending on what we are investigating, sometimes it is useful to start with a questionnaire and then, for example, follow up some specific points with an experiment, or a series of interviews, in order to fully explore some aspect of the phenomenon under study.
This chapter describes how to choose between and design questionnaires, interviews and focus group studies and using two examples illustrates the advantages of combining a number of approaches when conducting HCI research
Recruiting Older Workers: Realities and Needs of the Future Workforce
This chapter examines literature pertaining to the recruitment of older workers. It begins by addressing the question of relevance and why older worker recruitment matters. It then examines what is known about older workers, including their attitudes, motivations, and behaviors. Next the chapter addresses what employers are looking for in older workers and, more specifically, discusses the continuum of employers’ practices from those that aggressively try to attract and retain older workers and apply a conservation model of older worker management to those that apply a depreciation model and focus primarily on retrenchment and downsizing older employees. Finally, it addresses how employers can recruit older workers through changes in organizational policies and practices
Aging, Retirement and Human Resources Management: A Strategic Approach
This chapter introduces the organizational view of retirement by exploring the relationship between organizational strategy and human resource management decisions regarding retirement. The authors begin with an overview of organizational strategy and discuss two methods used to plan for an aging and retiring workforce. Several key human resource decisions related to retirement are then addressed. In the pre-retirement phase, the role of HR In helping employees to prepare for retirement Is discussed, focusing primarily on financial planning and other retirement-related benefits. Next, human resource decisions pertaining to managing a retirement-ready workforce are discussed, addressing specifically the issues of knowledge transfer and motivating performance. Finally, interactions with individuals after retirement are discussed by looking at recruitment and bridge employment
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