• 전자공학회논문지B
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• 제33B권5호
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• pp.138-151
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• 1996

This paper proposes a genetic fuzzy controller ensemble (FCE) for improving the control performance of of fuzzy controller in the non-linear and complex problems. The design procedure of each fuzzy controller in the FCF consists of the following two stages, each of which is performed by different genetic algorithms. The first stage generates a fuzzy rule base that covers the training examples as many as possible. The second stage builds fine-tuned membership funcitons that make the control error as small as possible. These two stages are repeated independently upon the different partition patterns of input-output variables. The control performance of the proposed method is compared with that of wang and mendel's approach[1] in terms of either the percentage of successful controls reaching to the goal or the average traveling distance.

• ETRI Journal
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• 제36권1호
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• pp.69-79
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• 2014

The scheduling scheme in packet switching networks is one of the most critical features that can affect the performance of the network. Hence, many scheduling algorithms have been suggested and some indices, such as fairness and latency, have been proposed for the comparison of their performances. While the nature of Internet traffic is bursty, traditional scheduling algorithms try to smooth the traffic and serve the users based on this smoothed traffic. As a result, the fairness index mainly considers this smoothed traffic and the service rate as the main parameter to differentiate among different sessions or flows. This work uses burstiness as a differentiating factor to evaluate scheduling algorithms proposed in the literature. To achieve this goal, a new index that evaluates the performance of a scheduler with bursty traffic is introduced. Additionally, this paper introduces a new scheduler that not only uses arrival rates but also considers burstiness parameters in its scheduling algorithms.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.161-167
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• 2015

The performance of high power LEDs highly depends on the junction temperature. Operating at high junction temperature causes elevation of the overall thermal resistance which causes degradation of light intensity and lifetime. Thus, appropriate thermal management is critical for LED packaging. The main goal of this research is to improve thermal resistance by optimizing and comparing nano-pore silicon-based thermal substrate to insulated metal substrate and direct bonded copper thermal substrate. The thermal resistance of the packages are evaluated using computation fluid dynamic approach for 1 W single chip LED module.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.243-249
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• 2005

To improve the ride comfort and handling characteristics of a vehicle, an active suspension which is controlled by external actuators can be used. An active suspension can control the vertical acceleration of a vehicle and the tire deflection to achieve the desired suspension goal. For this purpose, Model Predictive Control (MPC) scheme is applied with the assumption that the preview information of the oncoming road disturbance is available. The predictive control approach uses the output prediction to forecast the output over a time horizon and determines the future control over the horizon by minimizing the performance index. The developed method is applied to a half car model of four degrees-of-freedom and numerical simulations show that the MPC controller improves noticeably the ride qualities and handling performance of a vehicle.

• Journal of electromagnetic engineering and science
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• 제13권4호
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• pp.199-207
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• 2013

Meeting electromagnetic compatibility (EMC) requirements can be a significant challenge for engineers designing today's electronic devices. Traditional approaches rely heavily on EMC design rules. Unfortunately, these design rules aren't based on the specific EMC requirements for a particular device, and they don't usually take into account the specific function of the circuits or the many design details that will ultimately determine whether the device is compliant. This paper describes a design methodology that relates design decisions to the product's EMC requirements. The goal of performance-based EMC design is to ensure that electronic designs meet EMC requirements the first time the product is tested. More work needs to be done before this concept reaches its full potential, but electronic system designers can already derive significant benefit by applying this approach to products currently under development.

• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.292-298
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• 2022

Femtocell networks can be a potential method for increasing the capacity of LTE networks, especially in indoor areas. However, unplanned deployment of femtocells results in co-tier interference and cross-tier interference problems. The interference reduces the advantages of implementing femtocell networks to a certain extent. The notion of Fractional Frequency Reuse (FFR) is proposed in order to reduce the impact of interference on the system's performance. In this paper, a dynamic approach for efficiently partitioning the spectrum is suggested. The goal is to enhance the capacity of femtocells, which will improve the performance of the system. The suggested strategy allocates less resources to the macrocell portion of the network, which has a greater number of femtocells deployed to maximize the utilization of available resources for femtocell users. The spectrum division would be dynamic. The proposed strategy is evaluated through a simulation using MATLAB tool. In conclusion, the results showed that the proposed scheme has the potential to boost the system's capacity.

• 제어로봇시스템학회논문지
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• 제6권3호
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• pp.317-328
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• 2000

This paper presents an effective approach to collision-free motion planning of a robot in the work-space including time-varying obstacles. The free arc is defined as a set composed of the configuration points of the robot satisfying collision-free motion constraint at each sampling time. We represent this free arc with respect to the new coordinate frame centered at the goal configuration and there for the collision-free path satisfying motion constraint is obtained by connecting the configuration points of the free arc at each sampling mined from the sequence of free arcs the optimality is determined by the performance index. Therefore the complicated collision-free motion planning problem of a robot is transformed to a simplified SUB_Optimal Collision Avoidance Problem(SOCAP). We analyze the completeness of the proposed approach and show that it is partly guaranteed using the backward motion. Computational complexity of our approach is analyzed theoretically and practical computation time is compared with that of the other method. Simulation results for two cally and practical computation time is compared with that of the other method. Simulation results for two SCARA robot manipulators are presented to verify the efficacy of the proposed method.

• Smart Structures and Systems
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• 제31권2호
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• pp.141-154
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• 2023

After an earthquake, information regarding potential damage to buildings close to the epicenter is very important during the initial emergency response. This study proposes the use of crowdsourced measured acceleration response data collected from smartphones located within buildings to perform system identification of building structures during earthquake excitations, and the feasibility of the proposed approach is studied. The principal advantage of using crowdsourced smartphone data is the potential to determine the condition of millions of buildings without incurring hardware, installation, and long-term maintenance costs. This study's goal is to assess the feasibility of identifying the lowest fundamental natural frequencies of buildings without knowing the orientations and precise locations of the crowds' smartphones in advance. Both input-output and output-only identification methods are used to identify the lowest fundamental natural frequencies of numerical finite element models of a real building structure. The effects of time synchronization and the orientation alignment between nearby smartphones on the identification results are discussed, and the proposed approach's performance is verified using large-scale shake table tests of a scaled steel building. The presented results illustrate the potential of using crowdsourced smartphone data with the proposed approach to identify the lowest fundamental natural frequencies of building structures, information that should be valuable in making emergency response decisions.

• 정보관리학회지
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• 제25권3호
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• pp.83-97
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• 2008

본고는 사서교사가 정보이용교육을 실시하는 데 필수적인 수행평가 방법 및 도구를 개발하기 위한 것이다. 사서교사의 정보이용교육에서 중요한 영역이 평가이다. 그런데 지금까지 사서교사의 교육 활동은 평가 방법에 대한 연구가 거의 없는 실정이다. 다만, 초 중등학교 정보와 도서관 교육과정에 평가 영역이 제시되어 있을 뿐이다. 이에, 사서교사가 실시하는 정보이용교육을 위한 수행평가 방법 및 도구의 개발은 중요한 의미를 갖는다. 평가 방법과 도구는 평가이론과 목표준거에 입각하여 개발되어야 한다. 본고의 최종적인 목적은 현장 사서교사들이 수행평가이론과 목표준거를 바탕으로 정보이용교육을 위한 다양한 수행평가 방법, 도구, 사례를 구현할 수 있도록 하는 데 있다.

• 한국정보시스템학회지:정보시스템연구
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• 제32권1호
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• pp.147-178
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• 2023

Purpose The mail goal of this study is to find out factors influencing users' satisfaction of public application with the emphasis of service quality of public web and public value. For this purpose, we applied IS success model to develop the research model that explains users's satisfaction and public performance. Design/methodology/approach The proposed research model was developed based on IS success model along with two moderating effects - Service Quality of Public Web and Public Value in order to empirically test proposed causal relationships withing the model. A total of 377 survey responses were analyzed by forming the structural equation modeling with AMOS 24.0. Findings The analysis results show that the service, information, and system quality from IS success model are positively associated with user satisfaction, which in turn is positively associated with public app performance. The results also show that the relationship between user satisfaction and public app performance is positively moderated by public value. However, the relationship between public app service quality and user satisfaction isn't moderated by public web service quality.