Robust observer-based fault estimation and accommodation of discrete-time piecewise linear systems

In this paper a new integrated observer-based fault estimation and accommodation strategy for discrete-time piecewise linear (PWL) systems subject to actuator faults is proposed. A robust estimator is designed to simultaneously estimate the state of the system and the actuator fault. Then, the estimate of fault is used to compensate for the effect of the fault. By using the estimate of fault and the states, a fault tolerant controller using a PWL state feedback is designed. The observer-based fault-tolerant controller is obtained by the interconnection of the estimator and the state feedback controller. We show that separate design of the state feedback and the estimator results in the stability of the overall closed-loop system. In addition, the input-to-state stability (ISS) gain for the closed-loop system is obtained and a procedure for minimizing it is given. All of the design conditions are formulated in terms of linear matrix inequalities (LMI) which can be solved efficiently. Also, performance of the estimator and the state feedback controller are minimized by solving convex optimization problems. The efficiency of the method is demonstrated by means of a numerical example.     

Evaluating R&D investment efficiency in China's high-tech industry

Research and development (R&D) investment activity plays a crucial role in developing high-tech industries. In recent decades, China has made sustained investments in its domestic high-tech industries, with the goal of increasing their productivity. This paper investigates the effect of this investment on relative R&D efficiency across China's high-tech sectors. Data Envelopment Analysis (DEA) was used to generate quantitative indices for sector comparisons. The analysis of this study indicates that overall R&D investment efficiency did not increase from 1998 to 2009, despite R&D expenditure increasing by 2188%. Over the same period, most sectors suffered from decreasing returns to scale (DRS), presumably also reflecting the inefficient R&D investment. Most of the sectors showed significant fluctuation on R&D investment efficiency. This research result indicates that the problem of China's high-tech industry may be from the inefficiency of its technology commercialization processes, and therefore represents a critical parameter for policy makers and managers.     

Intrinsic Factors for Continued ERP Learning: A Precursor to Interdisciplinary ERP Curriculum Design

Unilateral enterprise resource planning (ERP) curriculum improvements from the instructor's perspective are likely to generate only limited success. Understanding student motivations and beliefs with ERP systems is the missing link to effective ERP education. Relatively little attention in the ERP literature has been given to student learning associated with ERP experience, and almost none to factors influencing current and expected student beliefs and behaviors relative to ERP. The complexity of ERP systems demands that beliefs and behaviors be considered when planning ERP curricula. In the present study, the Theory of Planned Behavior was extended to examine students’ intentions to explore additional aspects of ERP after their class exercises. When considering all students, attitude and subjective norm had positive and significant effects on intentions to continue ERP learning. Subjective norm also affected attitude, and availability of support materials had a positive effect on subjective norm. Distinctive patterns are found for the construct relationships between student groups who valued ERP education (the engaged) and those who placed little or no value on ERP education (the undecided). Results from competing model analyses indicate that support materials influenced the engaged and undecided groups differently. Strategies for ERP curriculum design are provided.     

The impact of participation in sports on educational attainment—New evidence from Germany

We analyze the impact of exercising sports during childhood and adolescence on educational attainment. The theoretical framework is based on models of allocation of time and educational productivity. Using the rich information from the German Socio-Economic Panel (GSOEP), we apply generalized ordered probit models to estimate the effect of participation in sport activities on secondary school degrees and professional degrees. Even after controlling for important variables and selection into sport, we find strong evidence that the effect of sport on educational attainment is statistically significant and positive.     

Test Fairness: Internal and External Investigations of Gender Bias in Mathematics Testing

What two major approaches have been used to study gender bias in test scores? How do statistical DIF detection methods differ? How does DIF screening of items affect mean score differences?     

Extinction and retraining of simultaneous and successive flavor conditioning

In three experiments, rats received pairings of flavor conditioned stimuli with polycose unconditioned stimuli, in either a simultaneous or a sequential relation. Both temporal relations produced excellent conditioned increases in consumption of the flavors. Separate presentation of the flavors resulted in extinction in both cases. However, restoring the pairing of the flavor with polycose resulted in reconditioning only with the sequential, not with the simultaneous, relation.