• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.4
• /
• pp.809-816
• /
• 2010

This paper proposed about a load-balanced multi-agent model in mobile distribution environment to monitor moving patients and to deal with a situation of emergency. This model was designed to have a structure based on distribution framework by expanding a mobile system, and provides healthcare services based on real time situational information on moving patients. In order to overcome the limitation of middleware when we design system, we provided an abstract layer between applications and their base network infrastructure so that balance between QoS requests and network life can be maintained. In addition, clustering was used in cells for the efficient load distribution among multi-agents. By using Clustering FCM, we got optimal resources and had solve about transmission delay.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.3
• /
• pp.551-559
• /
• 2016

The present trend of increasing the penetration levels of Distributed Generator (DG) in the distribution network has made the issue of Islanding crucial for the reliable operation of the network. The islanding, if not detected early may lead to the collapse of the system as it can drive the distribution system to the cascaded failure. In this paper, an extensive study of the effect of DG placement and sizing is performed by dividing the system into different zones to obtain a reduced effect of islanding. The siting and sizing of DG is carried out to improve the overall voltage profile or/and reduction in active power loss using two stage Genetic Algorithm (GA). In the first stage a basic knockout selection is considered and the best population is taken for next stage, where roulette selection for crossover and mutation is performed for optimal placement and sizing of DGs. The effect of the islanding, due to load variations is reduced by optimal siting and sizing of DG. The effectiveness of the proposed scheme is tested on the IEEE 33 and 69 radial bus systems and the results obtained are promising.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.1
• /
• pp.133-151
• /
• 2019

In order to achieve faster content distribution speed and stronger fault tolerance, a P2P peer can connect to multiple peers in parallel and receive chunks of the data simultaneously. A critical issue in this environment is selecting a set of nodes participating in swarming sessions. Previous related researches only focus on performance metrics, such as downloading time or the round-trip time, but in this paper, we consider a new performance metric which is closely related to the network and propose a peer selection algorithm that produces the set of peers generating optimal worst link stress. We prove that the optimal algorithm is practicable and has the advantages with the experiments on PlanetLab. The algorithm optimizes the congestion level of the bottleneck link. It means the algorithm can maximize the affordable throughput. Second, the network load is well balanced. A balanced network improves the utilization of resources and leads to the fast content distribution. We also notice that if every client follows our algorithm in selecting peers, the probability is high that all sessions could benefit. We expect that the algorithm in this paper can be used complementary to existing methods to derive new and valuable insights in peer-to-peer networking.

• Smart Structures and Systems
• /
• v.18 no.3
• /
• pp.389-403
• /
• 2016

Structural deflection can be identified from measured strains from long gague sensors, but the sensor layout scheme greatly influences on the accuracy of identified resutls. To determine the optimal sensor layout scheme for accurate deflection identification of the tied arch bridge, the method of optimal layout of long-gauge fiber optic sensors is studied, in which the characteristic curve is first developed by using the bending macro-strain curve under multiple target load conditions, then optimal sensor layout scheme with different number of sensors are determined. A tied arch bridge is studied as an example to verify the effectiveness and robustness of the proposed method for static and dynamic deflection identification.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.4 no.2
• /
• pp.9-16
• /
• 2001

In this paper, general design process for Tracked Fighting Vehicle has been suggested. Stress analysis and optimal design for ply angle of IFV's composite upper hull has been calculated using KMA CIFV and it is contained exploratory development of design process. In this point, this paper applied composite to IFV's upper hull. Finite element mesh has been made using Matlab program, and we have analyzed stress based on the given material properties and ply arrangement. For each load condition, load distribution in plane and failure index are calculated by using Tasi-Hill criterion, which is composite failure criterion and analyzing change of failure index as change of ply angle. Finally, optimal ply angles of upper hull are calculated using KMA CIFV. We can estimate the decrease of weight for IFV's upper hull.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2006.04a
• /
• pp.283-290
• /
• 2006

Cable-stayed bridge is a bridge that consists of one or more pylons, with cables supporting the deck. Cable-stayed bridges have come into wide use recently because of their economy, stability, and excellent appearance. It is possible to achieve a uniform moment distribution in the stiffening girders mainly by prestressing the cables, which leads to a more economical design in material and weight than other types of bridges. However, to achieve a more uniform moment distribution is vague objective, so it cannot be easily defined as the optimization problem. In other words, the minimization of cost or weight as the objective is not directly related to the optimization of cable prestressing. Therefore, it has been considered as one of the most important, difficult and also interesting topics among many researchers and bridge engineers to determine the optimal tensioning strategy how to apply prestressing forces of the cables of cable-stayed bridge. A number of approaches (Wang et al. 1993, $Negr\~{a}o\;and\;Sim\~{o}es$ 1997, Agrawal 1997, Janjic et al. 2003) to determine the optimal cable tensions have been proposed in the literature. Among these approaches the unit load method (Janjic et al. 2003) is considered in this paper because it can take into account the actual construction process while other approaches are based on the configuration of the final structure only. In this paper, '2-step approach' based on the unit load method is proposed to find the optimal tensioning strategy especially for the atypical asymmetric bridge under construction, which has continuous deck supported by one pylon and stay cables. Some numerical results will be given to show the validity of the new approach suggested in this paper.

• KIEE International Transactions on Power Engineering
• /
• v.4A no.4
• /
• pp.207-213
• /
• 2004

In this paper, the on-line volt/var control algorithms of the Load Tap Changer (LTC) transformer and Shunt Capacitor (SC) are proposed for distribution volt/var compensation. In the existing volt/var control of the distribution substation, the feeder voltage and reactive power demand of the distribution are mainly controlled by the LTC transformer tap position and on/off operation of the Sc. It is very difficult to maintain volt/var at the distribution networks within the satisfactory levels due to the discrete operation characteristics of the LTC and SC. In addition, there is the limitation of the LTC and SC operation times, which affects their functional lifetimes. The proposed volt/var control algorithm determines an optimal tap position of the LTC and on/off status of the SC at a distribution substation with multiple connected feeders. The mathematical equations of the proposed method are introduced. A simple case study is performed to verify the effectiveness of the proposed method.

• Journal of Environmental Impact Assessment
• /
• v.22 no.6
• /
• pp.713-724
• /
• 2013

In terms of waste load allocation, inequality of waste load discharge must be considered as well as economic aspects such as minimization of waste load abatement. The inequality of waste load discharge between areas was calculated with Gini coefficient and was included as one of the objective functions of the multi-objective waste load allocation. In the past, multi-objective functions were usually weighted and then transformed into a single objective optimization problem. Recently, however, due to the difficulties of applying weighting factors, multi-objective genetic algorithms (GA) that require only one execution for optimization is being developed. This study analyzes multi-objective waste load allocation using NSGA-II-aJG that applies Pareto-dominance theory and it's adaptation of jumping gene. A sensitivity analysis was conducted for the parameters that have significant influence on the solution of multi-objective GA such as population size, crossover probability, mutation probability, length of chromosome, jumping gene probability. Among the five aforementioned parameters, mutation probability turned out to be the most sensitive parameter towards the objective function of minimization of waste load abatement. Spacing and maximum spread are indexes that show the distribution and range of optimum solution, and these two values were the optimum or near optimal values for the selected parameter values to minimize waste load abatement.

• Proceedings of the KIEE Conference
• /
• 1998.07c
• /
• pp.1059-1062
• /
• 1998

This paper which can simulate FRIENDS(Flexible Reliable Intelligent Electrical eNergy Delivery System) model of distribution electrical system presents a new algorithm. In the operation of FRIENDS model, dispersed energy storage(DES) systems have an important role. We can use the active and reactive power of DES to control customer's voltage. In this, the former means load levelling operation and the later means voltage control operation of DES. We focus our research on load levelling operation of DES. We develope an algorithm to get an optimal capacity and operation schedule of DES and then apply it to the FRIENDS model. The results show the effectiveness of the proposed method.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.2_1
• /
• pp.231-238
• /
• 2023

This paper develops the theory for a novel fault-tolerant, permanent magnet biased, 6-active-pole, homopolar magnetic bearing. The Lagrange Multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrices for the failed bearing. some numerical examples of distribution matrices are provided to illustrate the new theory. Simulations show that very much the same dynamic responses (orbits or displacements) are maintained throughout failure events (up to any combination of 3 coils failed for the 6 pole magnetic bearing) while currents and fluxes change significantly. The overall load capacity of the bearing actuator is reduced as coils fail. The same magnetic forces are then preserved up to the load capacity of the failed bearing.