• 한국자동차공학회논문집
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• 제8권5호
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• pp.138-147
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• 2000

Vehicle suspension systems are parts which effect performances of a vehicle such as ride quality, handing characteristics, straight performance and steering effort etc. Kinematic design is a decision of joints` position for straight performance and steering effort. But, when vehicle is rebounding and bumping, chang of joints` displacement is nonlinear and a surmise of straight performance and steering effort at that joints` position is difficult. So design of suspension systems is done through a inefficient method of tried-and-error depending on designer`s experience. In this paper, kinematic design of suspension systems was done through the optimal design using a genetic algorithm. For this optimal design, the function for quantification of straight performance and steering effort was made, and the kinematic design method of suspension systems having this function as the objective function was suggested.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.97-98
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• 2006

Fusion of decisions from multiple distributed sensor nodes is studied in this work. Based on the canonical parallel fusion model, we derive the optimal likelihood ratio based fusion rule with the assumptions of the generalized Gaussian noise model and the arbitrary fading channel. This optimal fusion rule, however, requires the complete knowledge of the channels and the detection performance of local sensor nodes. To mitigate these requirements and to provide near optimum performance, we derive suboptimum fusion rules by using high and low signal-to-noise ratio (SNR) approximations to the optimal fusion rule. Performance evaluation is conducted through simulations.

• 설비공학논문집
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• 제12권6호
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• pp.570-580
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• 2000

The performance simulation of refrigeration system for the automotive vehicles was peformed, in which the refrigerant was HFC-l34a as an alternative to CFC-12. The coefficient of performance of the system for HFC-l34a was lower than that for CFC-12 operated in the same operating and design conditions. The optimal design conditions were obtained as a function of optimum capacity ratios of condenser and evaporator.

• 한국정보통신학회논문지
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• 제10권2호
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• pp.271-275
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• 2006

STP는 토폴로지 구성방법에 따라 네트워크의 성능이 달라진다. 따라서 효율적인 네트워크 환경을 위하여 최적의 토폴로지를 구성할 필요가 있다. 본 논문은 이더넷에서 스위치들 사이의 효율적인 네트워크 구축을 위한 최적의 토폴로지 구성방법을 제안하였다. 루트스위치에서 송신한 프레임을 같은 도메인 안에 있는 스위치들이 프레임을 수신하는 시간을 수학적 모델로 계산하여 최적의 토폴로지 구성 방법을 도출하였다. 그리고 최적의 토폴로지에서의 루트 스위치의 위치에 따른 성능을 분석하였다. 성능 분석 결과 정방형으로 설계된 망에서 루트스위치가 중앙에 위치하게 설계하는 것이 효과적이라는 결론을 얻을 수 있었다.

• Earthquakes and Structures
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• 제23권5호
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• pp.419-430
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• 2022

The metallic energy dissipation device (EDD) has been widely accepted as a useful tool for passive control of buildings against earthquakes. The distribution of metallic EDDs in a multi-story building may have significant influence on its seismic performance, which can be greatly enhanced if the distribution scheme is properly designed. This paper addresses the optimal distribution problem in the aim of achieving a desired level of performance using the minimum number of metallic EDDs. Five local search heuristic algorithms are proposed to solve the problem. Four base structures are presented as numerical examples to verify the proposed algorithms. It is indicated that the performance of different algorithms may vary when applied in different situations. Based on the results of the numerical verification, the recommended guidelines are finally proposed for choosing the appropriate algorithm in different occasions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3689-3700
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• 2016

It is not practically feasible to apply hardware-based fault-tolerant schemes, such as hardware replication, in mobile devices. Therefore, software-based fault-tolerance techniques, such as checkpoint and rollback schemes, are required. In checkpoint and rollback schemes, the optimal checkpoint interval should be applied to obtain the best performance. Most previous studies focused on minimizing the expected execution time or response time for completing a given task. Currently, most mobile applications run in real-time environments. Therefore, it is extremely essential for mobile devices to employ optimal checkpoint intervals as determined by the real-time constraints of tasks. In this study, we tackle the problem of determining the optimal inter-checkpoint interval of checkpoint and rollback schemes to maximize the deadline meet ratio in real-time systems and to build a probabilistic cost model. From this cost model, we can numerically find the optimal checkpoint interval using mathematical tools. The performance of the proposed solution is evaluated using analytical estimates.

• 한국유체기계학회 논문집
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• 제9권2호
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• pp.13-18
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• 2006

This paper was studied to design Process considered flexibility and reliability of suction and discharge valves. Flexibility and reliability of valves are main important factors in compressor valves design. And they are incompatible with efficiency of compressor. In this study, we have performed the optimal design of CO2 compressor valves to consider these factors. At first, we analyzed performance simulation of compressor to obtain optimal flexibility level of valves. From this simulation, we could get some important data at valve design like the optimal natural frequency and the height of retainer. After that we studied to reliability of valves corresponding to optimal flexibility level by finite element method. For each case bending stress and natural frequency were obtained by it. Also we investigated the fatigue stability to obtain optimal valve shape that ensured to reliability.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1161-1166
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• 1993

The performances of a vehicle active suspension system with an optimal variable structure controller are compared to those of passive suspension system and active suspension systems with sky-hook and optimal controllers. The quater car model has a 2 DOF which accounts for vertical motions of a sprung and a unsprung masses. The transient responses are analyzed when a vehicle passing through a bump with a constant speed and the frequency responses are analyzed for white noise input at wheel. Particulary, RMS responses are also analyzed. It is shown that the optimal variable structure controller gives better performance of the vehicle active suspensio system than an optimal and a sky-hook controller.

• 한국통신학회논문지
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• 제29권5C호
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• pp.700-705
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• 2004

Autoencoder와 Fuzzy c-Means 알고리즘을 이용하여, 불완전한 데이터의 군집화를 위한 알고리즘이 본 논문에서 제안되었다. 본 논문에서 제안된 Optimal Completion Autoencoder Fuzzy c-Means (OCAEFCM)은 손상되어 불완전한 데이터의 최적 복원과 데이터의 군집화를 위해 Autoencoder Neural Network (AENN) 과 Gradient-based FCM (GBFCM)을 이용하였다. OCAEFCM 의 성능평가를 위해 IRIS 데이터와 금융기관에서 취득한 실제 데이터를 사용하였다 기존의 Optimal Completion Strategy FCM (OCSFCM)과 비교했을 때, 제안된 OCAEFCM 이 OCSFCM 보다 18％-20％의 성능 향상을 보여준다.

• 제어로봇시스템학회논문지
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• 제3권4호
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• pp.422-434
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• 1997

In this paper, a two-stage kinematic optimal design for a 3 degree of-freedom (DOF) excavator subsystem, which consists of boom, arm and bucket, is performed. The objective of the first stage is to find the optimal parameters of the joint-actuating mechanisms which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the second stage is to find the optimal link parameters which maximize the isotropic characteristic of the excavator subsystem throughout the workspace. It is illustrated that kinematic/dynamic performances of the kinematically optimized excavator subsystem have improved compared to those of original HE280 excavator, with respect to three performance indices such as maximum load handling capacity, maximum velocity capability, and acceleration capability.