Testing of linear models for optimal control of second-order dynamical system based on model-reality differences

In this paper, the testing of linear models with different parameter values is conducted for solving the optimal control problem of a second-order dynamical system. The purpose of this testing is to provide the solution with the same structure but different parameter values in the model used. For doing so, the adjusted parameters are added to each model in order to measure the differences between the model used and the plant dynamics. On this basis, an expanded optimal control problem, which combines system optimization and parameter estimation, is introduced. Then, the Hamiltonian function is defined and a set of the necessary conditions is derived. Consequently, a modified model-based optimal control problem has resulted. Follow from this, an equivalent optimization problem without constraints is formulated. During the calculation procedure, the conjugate gradient algorithm is employed to solve the optimization problem, in turn, to update the adjusted parameters repeatedly for obtaining the optimal solution of the model used. Within a given tolerance, the iterative solution of the model used approximates the correct optimal solution of the original linear optimal control problem despite model-reality differences. The results obtained show the applicability of models with the same structures and different parameter values for solving the original linear optimal control problem. In conclusion, the efficiency of the approach proposed is highly verified

The applicability of performance-based funding mechanisms in Malaysian Public Universities

A performance-based funding (PBF) mechanism is now widespread in educational institutions in both developed and developing countries. The Malaysian Government also has intention to implement PBF in public universities, yet no study has explored the applicability of PBF implementation in Malaysian public universities to date. Hence, this study examined the drivers to the introduction of PBF in Malaysian public universities. An exploratory two-phased mixed-methods approach was employed to retrieve views from participants pertaining to PBF implementation in order to develop a survey questionnaire based on the gathered information. The selected participants for the semi-structured interviews were senior officers from the Bursar Office, while the respondents of the survey questionnaires composed of Dean and Deputy Dean of all Malaysian public universities. Thematic, descriptive, and inferential analyses were applied to examine the gathered qualitative and quantitative data. The outcomes signified that the main applicability drivers to the implementation of PBF were government objectives, level of understanding, and autonomy. All the drivers exhibited significant relationships with PBF implementation, whereas statistically significant differences were observed in autonomy between Research/Apex Universities and Focused Universities. On the contrary, no significant difference was noted between government objectives and level of understanding across university categories. The study outputs enable the Malaysian Government to have greater confidence in developing and implementing the PBF mechanism in Malaysian public universities

The Effect of Dynamical Gauge Field on the Chiral Fermion on a boundary

We study the effect of dynamical gauge field on the Kaplan's chiral fermion on a boundary in the strong gauge coupling limit in the extra dimension. To all orders of the hopping parameter expansion, we prove exact parity invariance of the fermion propagator on the boundary. This means that the chiral property of the boundary fermion, which seems to survive even in the presence of the gauge field from a perturbative point of view, is completely destroyed by the dynamics of the gauge field.Comment: 16 pages (including 7 figures), LaTeX, UT-675, KEK-TH-39

Needs of Distance Learners at the Institute of Distance Education and Learning, Universiti Putra Malaysia

This is a survey study on a sample of 61 postgraduate students pursuing the Master of Science (Human Resource Development) degree at the Faculty of Educational Studies. This program coordinated by the Institute of Distance Education and Learning (IDEAL) at Universiti Putra Malaysia (UPM). The study focuses on learners' needs and support services required during the course of study at IDEAL. The area of study encompasses the personal, administrative and academic aspects of learner needs. The personal aspect is made up of learner readiness and guidance and counseling needs whereas the administrative aspect refers to the administrative and management support. The academic aspect includes learning materials and resources, course delivery, teaching and learning strategy and methodology as well as learner-facilitator interactions. Data were collected using self-designed questionnaires. Each questionnaire is made up of 70 items using the Likert-like scale and an open-ended question with three responses. The result revealed a learner profile which can be described as mostly males, married, aged more than 26 years, majority of whom have more than 10 years of work experience, and are either very far (>200km) or very near (<50) from the learning centre

Axial Vibration Analysis on Drillstring

The problem of drill string vibration occurs in drilling operations and it will affect the usage life of drill pipe and drill bits. Three types of vibration, which are axial, lateral and torsional vibrations exist in the drill string. In order to being able to guide a drillstring in any direction, came the significant task of modelling the whole process mathematically and physically. This paper will study on the axial vibration in drill string by using finite element modelling analysis to observe the dynamic behavior of drill string under several conditions. The structure of drill string mainly consists of drill pipe, which is 80% of the total drill string length, drill collars which are used to provide additional weight and stabilize the drill string, and drill bit which are used for drilling operation. Due to vibrations, are costly. Sometimes these parts can break unpredictably, or the bits may be dull while drilling. When this situation occurs, the whole assembly of drillstring has to be pulled out of the well, to replace the damaged parts in order to continue the drilling process. Axial vibration will increase the risk of early fatigue of components such as bit life reduction, pipe fatigue and failure in drill string. In this project, finite element analysis method is used to find the modal and harmonic frequencies of drill string. Using real field data, a drill string model is designed using ANSYS simulation software. The case studies on drill string model include surface drilling, intermediate drilling, and slim hole drilling. Parametric studies of this project consists of three parts, which are the effect of drill pipe length on frequency of drill string, the effect of rotary speed on frequency of drill string, and the effect of Weight On Bit (WOB) on harmonic response of drill string. The simulation is expected to generate natural frequency of drill string under different depth and harmonic frequency of the drill string when subjected to axial force. Drill string dynamic behavior under influence of length, speed and force will be observe

Family, learning environments, learning approaches, and student outcomes in a Malaysian private university

This paper presents the quantitative findings from a mixed methods study of students and faculty at a private medical university in Malaysia. In particular, the relationships among students’ individual characteristics, general self-efficacy, family context, university and classroom learning environments, curriculum, approaches to learning, and measures of students’ academic achievement, self-directed learning readiness and mental health at the student level. Data were collected from 392 students attending a private medical university in Malaysia. The findings from the partial least square path (PLSPATH) suggest that: (a) parental involvement continues to impact and influence student learning process, and related student outcomes, at the university level, and (b) a surface approach to learning is related to poor quality processes and outcomes and a deep approach to learning is related to high quality processes and outcomes

Numerical modelling of agglomerate degradation

In the processing industries particulate materials are often in the form of powders which themselves are agglomerations of much smaller sized particles. During powder processing operations agglomerate degradation occurs primarily as a result of collisions between agglomerates and between agglomerates and the process equipment. Due to the small size of the agglomerates and the very short duration of the collisions it is currently not possible to obtain sufficiently detailed quantitative information from real experiments to provide a sound theoretically based strategy for designing particles to prevent or guarantee breakage. However, with the aid of computer simulated experiments, the micro-examination of these short duration dynamic events is made possible. This thesis presents the results of computer simulated experiments on a 2D monodisperse agglomerate in which the algorithms used to model the particle-particle interactions have been derived from contact mechanics theories and, necessarily, incorporate contact adhesion. A detailed description of the theoretical background is included in the thesis. The results of the agglomerate impact simulations show three types of behaviour depending on whether the initial impact velocity is high, moderate or low. It is demonstrated that high velocity impacts produce extensive plastic deformation which leads to subsequent shattering of the agglomerate. At moderate impact velocities semi-brittle fracture is observed and there is a threshold velocity below which the agglomerate bounces off the wall with little or no visible damage. The micromechanical processes controlling these different types of behaviour are discussed and illustrated by computer graphics. Further work is reported to demonstrate the effect of impact velocity and bond strength on the damage produced. Empirical relationships between impact velocity, bond strength and damage are presented and their relevance to attrition and comminution is discussed. The particle size distribution curves resulting from the agglomerate impacts are also provided. Computer simulated diametrical compression tests on the same agglomerate have also been carried out. Simulations were performed for different platen velocities and different bond strengths. The results show that high platen velocities produce extensive plastic deformation and crushing. Low platen velocities produce semi-brittle failure in which cracks propagate from the platens inwards towards the centre of the agglomerate. The results are compared with the results of the agglomerate impact tests in terms of work input, applied velocity and damage produced