Evolutionary learning and global search for multi-optimal PID tuning rules

With the advances in microprocessor technology, control systems are widely seen not only in industry but now also in household appliances and consumer electronics. Among all control schemes developed so far, Proportional plus Integral plus Derivative (PID) control is the most widely adopted in practice. Today, more than 90% of industrial controllers have a built-in PID function. Their wide applications have stimulated and sustained the research and development of PID tuning techniques, patents, software packages and hardware modules. Due to parameter interaction and format variation, tuning a PID controller is not as straightforward as one would have anticipated. Therefore, designing speedy tuning rules should greatly reduce the burden on new installation and ‘time-to-market’ and should also enhance the competitive advantages of the PID system under offer. A multi-objective evolutionary algorithm (MOEA) would be an ideal candidate to conduct the learning and search for multi-objective PID tuning rules. A simple to implement MOEA, termed s-MOEA, is devised and compared with MOEAs developed elsewhere. Extensive study and analysis are performed on metrics for evaluating MOEA performance, so as to help with this comparison and development. As a result, a novel visualisation technique, termed “Distance and Distribution” (DD)” chart, is developed to overcome some of the limitations of existing metrics and visualisation techniques. The DD chart allows a user to view the comparison of multiple sets of high order non-dominated solutions in a two-dimensional space. The capability of DD chart is shown in the comparison process and it is shown to be a useful tool for gathering more in-depth information of an MOEA which is not possible in existing empirical studies. Truly multi-objective global PID tuning rules are then evolved as a result of interfacing the s-MOEA with closed-loop simulations under practical constraints. It takes into account multiple, and often conflicting, objectives such as steady-state accuracy and transient responsiveness against stability and overshoots, as well as tracking performance against load disturbance rejection. These evolved rules are compared against other tuning rules both offline on a set of well-recognised PID benchmark test systems and online on three laboratory systems of different dynamics and transport delays. The results show that the rules significantly outperform all existing tuning rules, with multi-criterion optimality. This is made possible as the evolved rules can cover a delay to time constant ratio from zero to infinity based on first-order plus delay plant models. For second-order plus delay plant models, they can also cover all possible dynamics found in practice

Malaysia and China students’ feedback on the implementation of critical thinking pedagogy: a case study

Having a knowledgeable and highly skilled human capital is an important factor for Malaysia to transform its economy towards achieving a developed nation and high-income status by the year 2020. Hence, the Malaysian government strives to improve the enrolment of local and international post-graduate students by providing an effective learning process to ensure their quality. This research aimed at describing the impact of critical thinking pedagogy using case-based learning in curriculum studies course among postgraduate students. It was a case study with qualitative approach. Interview technique was used in this study whereby five students who enrolled in curriculum studies course were selected as the respondents. The study sample underwent learning through critical thinking pedagogy using SCSCBL interactive application. Overall, the findings showed that the teaching approach of using the case-based learning can promote critical thinking skills among pre-service and in-service teachers. This study has provided positive implications on the postgraduates’ soft skill development as preparation for their future career

El dólar chino vinculado al de Hong Kong durante la crisis global

This paper explores the domestic price level and trade competitiveness of Hong Kong in addition to the compatibility of this dollar-based currency board to the criteria inspired by the optimum currency area (OCA) theory. On price and competitiveness, findings point out that during the turmoil Hong Kong had not performed as well as that in the past and an apparent reason for this is the inflows of hot capital from abroad especially of the US that fuelled rising property prices. On conformity to the OCA criteria, the findings broadly corroborate the fixed exchange regime with the US as the monetary anchor country but at the same time China appears as a prospective contender to US as the monetary anchor. In the longer run, amidst the prolonged economic and monetary weaknesses in the US plus the emergence of renminbi as a global currency, Hong Kong might as well unify its exchange rate with the Chinese money.Este documento explora el nivel de precios internos y la competitividad comercial de Hong Kong, además de la compatibilidad de esta caja de conversión basada en el dólar con los criterios inspirados en la teoría de la zona monetaria óptima (ZMO). En cuanto al precio y la competitividad, los hallazgos señalan que durante la agitación Hong Kong no se había desempeñado tan bien como en el pasado y una razón aparente de esto son las entradas de capital proveniente del extranjero, especialmente de los Estados Unidos, que impulsaron el alza de los precios de las propiedades. En conformidad con los criterios de la ZMO, los hallazgos corroboran ampliamente el régimen de cambio fijo con los Estados Unidos como ancla monetaria, pero, al mismo tiempo, China aparece como un posible candidato a contendor de Estados Unidos como ancla monetaria. A más largo plazo, en medio de la prolongada debilidad económica y monetaria en los Estados unidos, más el surgimiento del renminbi como moneda global, Hong Kong podría también unificar su tipo de cambio con el dinero chino

TRIZ: an alternate way to solve problem for student

Inventive problem solving is an alternative way of solving problem for student. 60 years ago, in 1956, Altshuller published a new, constructive and methodical approach ideas on problem solving to offer to the world. Even though TRIZ originally meant for fields of industry domains, it has solved problems in other field using some common principles. Thus, this methodology has spread to over 35 countries across the world. It is now being taught in several universities and it has been applied by a number of global organizations who have found it particularly useful to solve their problem. In 2017, KSSM curriculum has been revised to cope up this 21st century demand. This paper is a potentially useful for TRIZ beginner, as an alternative to solve problem comparable to common problem solving method. This paper also discussed the limitation of other common problem method which leads the advantages of using TRIZ

A Richer Understanding of Australia’s Productivity Performance in the 1990s: Improved estimates based upon firm-level panel data

Australia’s productivity performance is characterized by important differences across continuing firms, frequent entry of new firms, and substantial exit of firms which, for one reason or another, decide to cease production. These basic facts call into question the appropriateness of measuring productivity using an aggregate production function that is based upon a representative firm. This study relaxes the standard assumptions that industries are comprised of a set of homogeneous firms, the set of which are constant over time. Instead, we apply a semi-parametric production to continue production. The model controls for the relationship between productivity shocks and input choices and the inter-relationship between these and the decision to continue production. Using the Business Longitudinal Survey we estimate an improved set of production functions for twenty-five two-digit industries in Australia. We use these results to examine aggregate industry-level productivity performance. We use a new aggregation method in calculating these changes which allows us to separate productivity changes and output composition changes which sheds new light on industry-level productivity performance in Australia