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In this paper, a novel Lyapunov–Krasovskii stable fuzzy proportional-integral-derivative (PID) (FPID) controller is introduced for load frequency control of a time-delayed micro-grid (MG) system that benefits from a fuel cell unit, wind turbine generator and plug-in electric vehicles.

Using the Lyapunov–Krasovskii theorem, the adaptation laws for the consequent parameters and output scaling factors of the FPID controller are developed in such a way that an upper limit (the maximum permissible value) for time delay is introduced for the stability of the closed-loop MG system. In this way, there is a stable FPID controller, the adaptive parameters of which are bounded. In the obtained adaptation laws and the way of stability analyses, there is no need to approximate the nonlinear model of the controlled system, which makes the implementation process of the proposed adaptive FPID controller much simpler.

It has been shown that for a different amount of time delay and intermittent resources/loads, the proposed adaptive FPID controller is able to enforce the frequency deviations to zero with better performance and a less amount of energy. In the proposed FPID controller, the increase in the amount of time delay leads to a small increase in the amount of overshoot/undershoot and settling time values, which indicate that the proposed controller is robust to the time delay changes.

Although the designed FPID controllers in the literature are very efficient in being applied to the uncertain and nonlinear systems, they suffer from stability problems. In this paper, the stability of the FPID controller has been examined in applying to the frequency control of a nonlinear input-delayed MG system. Based on the Lyapunov–Krasovskii theorem and using rigorous mathematical analyses, the stability conditions and the adaptation laws for the parameters of the FPID controller have been obtained in the presence of input delay and nonlinearities of the MG system.

This study aims to investigate the feasibility of proposed microgrid (MG) that comprises photovoltaic, wind turbines, battery energy storage and diesel generator to supply a residential building in Grindelwald which is chosen as the test location.

Three operational configurations were used to run the proposed MG. In the first configuration, the electric energy can be vended and procured utterly between the main-grid and MG. In the second configuration, the energy trade was performed within 15 kWh as the maximum allowable limit of energy to purchase and sell. In the third configuration, the system performance in the stand-alone operation mode was investigated. A whale optimization technique is used to determine the optimal size of MG in all proposed configurations. The cost of energy (COE) and other measures are used to evaluate the system performance.

The obtained results revealed that the first configuration is the most beneficial with COE of 0.253$/KWh and reliable 100%. Furthermore, the whale optimization algorithm is sufficiently feasible as compared to other techniques to apply in the applications of MG.

The value of the proposed research is to investigate to what extend the integration between MG and main-grid is beneficial economically and technically. As opposed to previous research studies that have focused predominantly only on the optimal size of MG.

This paper aims to examine the pedagogical strategies and challenges of selected multigrade (MG) schoolteachers in Albay, Philippines.

This study utilized a case study design using a validated semi-structured instrument with in-depth interviews to ten MG teachers, observation and document analysis. Qualitative data analyses such as content and thematic analyses were used in analyzing the data.

The results show that MG teachers use a variety of overlapping and supplementary instructional strategies such as (1) teaching one topic to all grades and at varying levels of difficulty using differentiated activity, (2) “jump-jump strategy”/teaching one grade while others work independently and (3) peer teaching or tutoring. However, there are several pedagogical challenges that MG teachers are faced with: (1) conflict between the medium of instructions and grade grouping, (2) problems with lesson planning, (3) unfocused instruction, (4) insufficient learners' materials, (5) absence of training prior to MG teaching and (6) the negative perception of the effectiveness of MG instructions.

The research is limited within the context of the participants and focuses on the pedagogical strategies and challenges in the implementation of MG teaching.

The results of this study can serve as a reference on how to support and strengthen MG instruction.

This study provides a research-based overview of MG schools from the grassroots level and adds to the limited studies of MG education in the Philippines.

Much previous research on improving information retrieval applications has focused on developing entirely new systems with advanced searching features. Unfortunately, most users seldom utilize these advanced features. This research explores the use of a software agent that assists the user during the search process. The agent was developed as a separate, stand‐alone component to be integrated with existing information retrieval systems. The performance of an information retrieval system with the integrated agent was subjected to an evaluation with 30 test subjects. The results indicate that agents developed using both results from previous user studies and rapidly modeling user information needs can result in an improvement in precision. Implications for information retrieval system design and directions for future research are outlined.

The specific challenges with which companies pursuing international manufacturing strategies are faced, if their output also contains a service dimension, are addressed. A theoretical framework is proposed based on three virtually complementary perspectives by integrating international production, demand, and contemporary ICT‐based theory. Subsequently, an exploratory case study in a pure service environment is described that illustrates the value of the framework. The present study provides a starting‐point for further research in the international manufacturing sector. It is possible, for example, to apply the theoretical framework to case studies in internationally‐operating companies delivering a mix of goods and services. Moreover, the framework has proven to be useful in improving the European structure of the case company. This is a notable and promising side‐effect of the exploratory study, at least from a managerial point of view.

Asian languages such as Japanese, Korean and in particular Chinese, are beginning to gain popularity in the information retrieval (IR) domain. The quality of IR systems has traditionally been judged by the system’s retrieval effectiveness which, in turn, is commonly measured by data recall and data precision. This paper proposes and describes a process for generating an automatic Chinese thesaurus that can be used to provide related terms to a user’s queries to enhance retrieval effectiveness. In the absence of existing automatic Chinese thesauri, techniques used in English thesaurus generation have been evaluated and adapted to generate a Chinese equivalent. The automatic thesaurus is generated by computing the co‐occurrence values between domain‐specific terms found in a document collection. These co‐occurrence values are in turn derived from the term and document frequencies of the terms. A set of experiments was subsequently carried out on a document test set to evaluate the applicability of the thesaurus. Results obtained from these experiments confirmed that such an automatic generated thesaurus is able to improve the retrieval effectiveness of a Chinese IR system.

Increased investment of a photovoltaic (PV) array makes it essential for the client to attain better results from the PV system. The nonlinearity of the PV array and the revolution and rotation of the earth require the appliance of maximum power point tracking (MPPT) to the system. Accordingly, grid connected PV systems have turn out to be renowned, because they do not require battery back-ups to accomplish MPPT. Stand-alone systems could also attain MPPT; however, they require appropriate battery back-ups for this function.

This survey intends to formulate a review on the PV-based microgrid (MG) systems. Here, the literature analyses on diverse techniques associated with PV-based MG systems. It reviews 65 research papers and states the significant analysis. Initially, the analysis depicts various controllers that are contributed in different papers. Subsequently, the analysis also focuses on various features such as PV capacity and inverter topology, and it also analyses the renewable grid source that are exploited in each paper. Furthermore, this paper provides the detailed study regarding the chronological review and performance achievements in each contribution. Finally, it extends the various research issues which can be useful for the researchers to accomplish further research on PV-based MG systems.

This paper has presented a detailed review on PV-based MG systems that were enumerated in the above sections. Here, various controllers along with their better achievements were analyzed and described. From the review, it was known that several PV-based MG systems were really at the point for enabling better power output and conversion efficiency. In conclusion, this paper reviewed about 65 research papers and declared the significant analysis. Initially, the analysis also focused on various controller classifications in PV-based MG systems that were reviewed in this paper. Subsequently, the analysis also focused on various features, such as PV capacity and inverter topology. The analysis also reviewed the performance achievements and renewable gird source that were exploited in PV-based MG systems. At last, this paper has presented various research issues which can be useful for the researchers to accomplish further research on the features of PV-based MG systems.

This paper presents a brief analysis of PV-based MG systems. This is the first work that uses PV-based MG systems for better regulation of MPPT.

This study aims to investigate the daily performance of the proposed microgrid (MG) that comprises photovoltaic, wind turbines and is connected to the main grid. The load demand is a residential area that includes 20 houses.

The daily operational strategy of the proposed MG allows to vend and procure utterly between the main grid and MG. The smart metre of every consumer provides the supplier with the daily consumption pattern which is amended by demand side management (DSM). The daily operational cost (DOC) CO2 emission and other measures are utilized to evaluate the system performance. A grey wolf optimizer was employed to minimize DOC including the cost of procuring energy from the main grid, the emission cost and the revenue of sold energy to the main grid.

The obtained results of winter and summer days revealed that DSM significantly improved the system performance from the economic and environmental perspectives. With DSM, DOC on winter day was −26.93 ($/kWh) and on summer day, DOC was 10.59 ($/kWh). While without considering DSM, DOC on winter day was −25.42 ($/kWh) and on summer day DOC was 14.95 ($/kWh).

As opposed to previous research that predominantly addressed the long-term operation, the value of the proposed research is to investigate the short-term operation (24-hour) of MG that copes with vital contingencies associated with selling and procuring energy with the main grid considering the environmental cost. Outstandingly, the proposed research engaged the consumers by smart meters to apply demand-sideDSM, while the previous studies largely focused on supply side management.

This paper proposes a model based on minority game (MG) theory to support the decision-making regarding the efficient allocation and exploitation of resources/services among the partners of a cloud manufacturing (CMfg) system. CMfg system is a new manufacturing paradigm to share manufacturing capabilities and resources on a cloud platform. The use of a decision model to organize and manage the resources and services provided by the autonomous participants of a CMfg has crucial relevance for the system's effectiveness and efficiency.

This research proposes a noncooperation model based on MG theory. The MG is designed to make decisions on the use of resources/services among the partners of CMfg with private information. A simulation environment was developed to test the efficiency of the proposed decision model. Moreover, an ideal decision model with complete information among the partners was used as a benchmark model.

The simulation results show how the application of the proposed MG model outperforms the MG model usually proposed in the literature. In particular, the proposed decision model based on private information has an efficiency closer to the ideal model with complete information among the partners of a CMfg.

This paper advances knowledge about the application of MG in the field of CMfg system. The proposed decision-making model based on MG is a promising approach to help enterprises, and especially small and medium enterprises, to participate in CMfg initiatives and to develop their business.

The purpose of this paper is to design and develop precipitation hardened Al-Mg alloy imparting enhanced strength with acceptable ductility through minor addition of Sc and Cr by using multi-objective genetic algorithm-based searching. In earlier attempts of strengthening aluminum alloys, owing to the formation of Al₃Sc and Al₇Cr phase, addition of Sc and Cr have yielded attractive precipitation hardening, respectively. Both the Al-Sc and Al-Cr system are quench sensitive due to presence of a sloping solvus in their phase diagrams. It is also known that both the Al₃Sc and Al₇Cr phases nucleate directly from the supersaturated solid solution without formation of GP-zones or transient phases prior to the formation of the Al₃Sc and Al₇Cr. Sc also found to have beneficial effect on the corrosion property of such alloys. In view of the above, it is of interest to explore the possibility of enhancing the age hardening effect in Al-Mg alloy by addition of Sc and Cr.

The paper uses an approach where experimental information of two different alloy systems (namely, Al-Mg-Sc and Al-Cr) has been combined to generate a single database involving the potential features of both the systems with the aim to formulate the suitable artificial neural network (ANN) models for strength and ductility. The models are used as the objective functions for the optimization process. The patterns of the optimized Pareto front are analyzed to recognize the optimal property of the alloy system. The hitherto unexplored Al-Mg-Sc-Cr alloy, designed from the Pareto solutions and suitably modified on the basis of prior knowledge of the system, is then synthesized and characterized.

The paper has demonstrated the ANN- and genetic algorithm (GA)-based design of a hitherto unexplored alloy by utilizing the existing information concerning the component alloy systems. The paper also established that analyses of the Pareto solutions generated through multi-objective optimization using GA provide an insight of the variation of the parameters at different combination of strength and ductility. It also revealed that the Al-Mg-Sc-Cr alloy has exhibited a two-stage age hardening effect. The first and second stages are due to the precipitation of Al₃Sc and Al₇Cr phases, respectively.

In the present study the two alloy systems are used in tandem to develop models to describe the properties involving the distinct mechanistic features of phase evolution inherent in both the systems. Though the ANN models having the capability to capture huge non-linearity of a system have been employed to predict the convoluted effects of those characteristics when an alloy containing Mg, Sc and Cr are added simultaneously, but the ANN models predictions can be checked experimentally by the future researchers.

The paper demonstrates the role of scandium and chromium addition on the ageing characteristics of the alloy by analyzing the age hardening behavior of the designed alloy in cast and cold rolled condition clearly.

The approach stated in this paper is a novel one, in the sense that experimental data of two different alloy systems have been clubbed to generate a single database with the aim to formulate the suitable ANN models for strength and ductility.