Comparing Two Meta-Heuristic Approaches for Solving Complex System Reliability Optimization
Hadi Akbarzade Khorshidi,
Sanaz Nikfalazar
Issue:
Volume 4, Issue 2-1, April 2015
Pages:
1-6
Received:
21 January 2015
Accepted:
22 January 2015
Published:
2 March 2015
Abstract: Using meta-heuristic approaches to solve reliability and redundancy allocation problems (RRAP) has become attractive for researchers in recent years. In this paper, an optimization model is presented to maximize system reliability and minimize system cost simultaneously for multi-state weighted k-out-of-n systems. The model tends to optimize system design and maintenance activities over functioning periods that provides a dynamic modeling. A recently developed meta-heuristic approach imperialist competitive algorithm (ICA) and genetic algorithm (GA) are used to solve the model. The computational results have been compared to find out which approach is more appropriate for solving complex system reliability optimization models. It is shown that GA can find the better solution while ICA is a faster approach. In addition, an investigation is done on different parameters of the ICA.
Abstract: Using meta-heuristic approaches to solve reliability and redundancy allocation problems (RRAP) has become attractive for researchers in recent years. In this paper, an optimization model is presented to maximize system reliability and minimize system cost simultaneously for multi-state weighted k-out-of-n systems. The model tends to optimize system...
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Power Assessment of the Human Ankle during the Stance Phase of Walking for Designing a Safe Active Prosthesis in Below-Knee Amputees
Sara Soltani Ch.,
Ali Esteki
Issue:
Volume 4, Issue 2-1, April 2015
Pages:
7-11
Received:
2 February 2015
Accepted:
5 February 2015
Published:
2 March 2015
Abstract: Many studies have been done on the biological human ankle and prosthesis replaced with this limb. Although some of these works targeted to design a prosthesis which mimics the behavior of biological ankle, additional system is required to support the elastic components; any of them have obviously introduced an active system in designing ankle prosthesis until now. In this study the power of the non-disabled human ankle joint was examined during the stance phase of walking in sagittal plane. The study aimed to better understand the ankle’s dynamic behavior for designing foot prosthesis with active mechanism. Kinematic and Kinetic data of the lower limb were collected from 18 healthy, young subjects (i.e. 6 females and 13 males) walking over a speed range of slow, normal and fast (i.e. 0.86 to 1.80 m/s). The ankle moment versus angle curves were plotted and total, mean and maximum values of powers were calculated for each trial. The results indicated that the total, mean and maximum values of the power could increase as the walking speed increased. The main findings of this study were the total, mean and maximum values of the power as a function of the linear velocity of walking. These results showed that the speed of 1.06 m/s was a critical velocity, below which the system was negative, showing energy consumer system, and above it the system was positive, suggesting generated energy. With the intent to design a prosthesis mimicking a biologic foot, an augmented system which is able to adjust the power to the speed is necessary.
Abstract: Many studies have been done on the biological human ankle and prosthesis replaced with this limb. Although some of these works targeted to design a prosthesis which mimics the behavior of biological ankle, additional system is required to support the elastic components; any of them have obviously introduced an active system in designing ankle prost...
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