A new model of job design: Initial evidence and implications for future research

Clegg and Spencer's (2007) model of job design synthesizes and extends recent conceptions of the job design process by incorporating variables such as knowledge, motivation, and trust into a cyclical and dynamic system. The objective of this study was to examine the sequential organization of variables that comprise the model, as a basis from which to justify further investigations of the model's dynamic properties. Data were collected via questionnaires from 432 participants in two work organizations. Results obtained from structural equation modeling are broadly supportive of the proposed relationships between the variables. Implications of this initial study for future research and practice are discussed. © 2011 Wiley Periodicals, Inc.     

A STUDY OF SPECIMEN SIZE ON J-R CURVE BEHAVIOUR

This paper presents results from an experimental programme to study size effects in J-R curves. Results are presented from unloading compliance R curve tests on different sized single edge notch bend specimens of nickel aluminium bronze and compared with previously published R curve data on a Ti3A1-2.5V titanium and an HY 100 steel alloy. The crack growth resistance was measured in terms of the standard fracture resistance J, J corrected for crack growth and the J modified parameter proposed by Ernst. It was observed that following a region of size independence small specimen J-R curves could fall either above or below the large specimen curve. It was found that although the limit to J controlled crack growth could be extended the limit is not unique but dependent on material type.     

Quantitative characterization of the substructure of AISI 316 stainless steel resulting from creep

The substructure of AISI 316 stainless steel resulting from creep deformation has been quantitatively characterized using transmission electron microscopy. The specimens were tested at temperatures and stresses ranging from 593° to 816°C and 8000 to 35,000 psi, respectively. Subgrains whose boundaries are predominantly (111) twist boundaries were formed in all tests at and above 704°C but were observed very infrequently at 650°C and were completely absent after creep at 593°C. The subgrain diameter,d, and the mobile dislocation density, ρ, were found to vary with the applied stress, σ_a, according to:d =kσ_a ^-1 and ρα σ_a ². Subgrain misorientation varys from less than 0.1 to 1 deg in each specimen seemingly independent of all parameters evaluated. A double triple node dislocation configuration was frequently observed in all specimens. Its relation to the deformation process is discussed in a mechanism involving the breaking of attractive dislocation nodes. Formerly Graduate Student, Materials, Science and Metallurgical Engineering Department, University of Cincinnati, Cincinnati, Ohio 45221     

Fracture mechanics assessment of industrial pressure vessel failures

Fracture mechanics assessment procedures, such as BSI PD6493; 1991, R6 and ASME XI, have become well established in industry. These published procedures provide methods for assessing the acceptability of flaws in fusion welded structures. For such procedures to be used with confidence, it is essential that their application be validated by comparison with large scale fracture mechanics tests, and actual structural failures. This paper describes eight industrial pressure vessel failures, for which PD6493 fracture assessments have been performed. It has been demonstrated that the assessment procedures are safe to use, provided that input data are reliable.     

Model-based ideal testing of hardware description language (HDL) programs

Software and Systems Modeling - An ideal test is supposed to show not only the presence of bugs but also their absence. Based on the Fundamental Test Theory of Goodenough and Gerhart (IEEE Trans...     

Design and implementation of a multiagent stock trading system

Stock trading is one of the key items in an economy and estimating its behavior and taking the best decision in it are among the most challenging issues. Solutions based on intelligent agent systems are proposed to cope with those challenges. Agents in a multiagent system (MAS) can share a common goal or they can pursue their own interests. That nature of MASs exactly fits the requirements of a free market economy. Although existing studies include noteworthy proposals on agent‐based market simulation and researchers discuss theoretical design issues of agent‐based stock exchange systems, unfortunately only a very few of the studies consider exact development and implementation of multiagent stock trading systems within the software engineering perspective and guides to the software engineers for constructing such software systems starting from scratch. To fill this gap, in this paper, we discuss the development of a multiagent‐based stock trading system by taking into consideration software design according to a well‐defined agent oriented software engineering methodology and implementation with a widely‐used MAS software development framework. Each participant in the system is first designed as belief–desire–intention agents with their facts, goals, and plans, and then belief–desire–intention reasoning and behavioral structure of the designed agents are implemented. Lessons learned during design and development within the software engineering perspective and evaluation of the implemented multiagent stock exchange system are also reported. Copyright © 2011 John Wiley & Sons, Ltd.     

Efficiently serving dynamic data at highly accessed web sites

We present architectures and algorithms for efficiently serving dynamic data at highly accessed Web sites together with the results of an analysis motivating our design and quantifying its performance benefits. This includes algorithms for keeping cached data consistent so that dynamic pages can be cached at the Web server and dynamic content can be served at the performance level of static content. We show that our system design is able to achieve cache hit ratios close to 100% for cached data which is almost never obsolete by more than a few seconds, if at all. Our architectures and algorithms provide more than an order of magnitude improvement in performance using an order of magnitude fewer servers over that obtained under conventional methods.