• Earthquakes and Structures
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• 제17권1호
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• pp.49-61
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• 2019

A novel asymmetrical resistance friction damper (ARFD) was proposed in this study to be applied on a rocking column base. The damper comprises multiple steel plates and was fastened using high-strength bolts. The sliding surfaces can be switched into one another and can cause strength to be higher in the loading direction than in the unloading direction. By combining the asymmetrical resistance with the restoring resistance that is generated due to an axial load on the column, the rocking column base can develop a self-centering behavior and achieve high connection strength. Cyclic tests on the ARFD proved that the damper performs a stable asymmetrical hysteretic loop. The desired hysteretic behavior was achieved by tuning the bolt pretension force and the diameter of the round bolt hole. In this study, full-scale, flexural tests were conducted to evaluate the performance of the column base and to verify the analytical model. The results indicated that the column base exhibits a stable self-centering behavior up to a drift angle of 4%. The decompression moment and maximum strength reached 42% and 88% of the full plastic moment of the section, respectively, under a column axial force ratio of approximately 0.2. The strengths and self-centering capacity can be obtained by determining the bolt pretension force. The analytical model results revealed good agreement with the experimental results.

• 디자인학연구
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• 제11권3호
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• pp.219-228
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• 1998

자동차에 대한 사용자의 욕구 다양화와 개성화가 '차량 꾸미기'로 표출되는 현상이 심화되고, 그에 따른 디자인 측면의 질적 저하와 성능과 기능 측면에서의 안정성에 우려가 발생되고 있다. 한국에 있어서의 튜닝은 관련 법규 및 전문 업의 미비상태와 무절제한 튜니으올 인해 전체적인 조형성과 기능적인 측면이 무시된 덧 대기식 작업이라는 지적과 함께 사회적 문제까지 비화되고 있는 현실이다. 본 연구에서는 커스터마이징을 도입하여 드레스업 용품과 다양한 튜닝 부품을 개발하여 고객 만족에 접근하고 있는 해외 양산 차 메이커와 전문 튜너(tuner)들을 중심으로 튜닝 사례와 드레스 업 용품 류를 차량의 부위별로 고찰해 보았다. 향후 자동차 스타일링의 방향설정에 있어서의 과제는 일반 소비자의 의식이 개인의 특성이 강조된 코디네이션에 대한 개념추구가 더욱 심화될 것이며, 라이프 스타일에 보다 밀착된 형태로의 소비자 니즈의 세련 화는 한층 진전될 것이다. 그 동안 국내 자동차시장의 소비자는 제품디자인을 생사자 중심에서 제시된 틀 안에서 수용하여 왔으나, 생산구조, 사회구조, 산업형태의 변화와 그에 따른 디자인 행위 그리고 디자인 가치의 변화를 초래할 것이다. 그에 따라 메이커와 디자이너는 이러한 환경 구조의 전환을 인지하고 또 다른 가능성을 모색하는 관계로써 상품 이면에 내재한 사회 문화적 의미, 즉 기호의 생산과 소비에 대해 진지하게 성찰할 필요가 있으리라 사료된다.

• 대한전기학회논문지
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• 제35권5호
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• pp.177-184
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• 1986

An effective cartesian coordinate model is presented to control a robot motion along a prescribed timebased hand trajectory in cartesian coordinates and to provide an adaptive feedback design approach utilizing self-tuning control methods without requiring a detailed mathematical description of the system dynamics. Assuming that each of the hybrid variable set of velocities and forces at the cartesian coordinate level is mutually independent, the dynamic model for the cartesian coordinate control is reduced to first-order SISO models for each degree of freedom of robot hand, including a term to represent all unmodeled effects, by which the number of parameters to be identified is minimized. The self-tuners are designde to minimize a chosen performance criterion, and the computed control forces are resolved into applied joint torques by the Jacobian matrix. The robustness of the model and controller is demonstrated by comparing with the other catesian coordinate controllers.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.291-294
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• 1999

This paper presents a GaAs MESMET self oscillating mixer for high efficiency L-band frequency conversion with small chip area consumption. Main circuit topology is consist of cascoded two FET with resonating part. The circuit is designed as unstably nonlinear for limited frequency band. FET with drain shorted to source is used for frequency tuning element. Linear conversion gain of -18.83 ㏈ is achieved with 9mA and 4V consumption. Input 1㏈ compression point is more than 11㏈m. The chip area is 1.4$\times$1.4 mm.

• 제어로봇시스템학회논문지
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• 제6권1호
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• pp.8-14
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• 2000

In this paper, three adaptive sliding mode control algorithms, which self-tune both the sliding mode gain and the boundary layer thickness, are proposed. The first algorithm uses a gain adaptation rule is combined with the boundary layer thickness adaptatioin rule to satisfy the sliding condition. In the third algorithm, the computation burden of the second algorithm is reduced further, and therefore no extra cost is required for real-time implementation. Due to the mixed sliding mode gain and the boundary layer thickness adaptation scheme, the tracking error and the chattering of the control input can be reduced greatly.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1998년도 추계학술대회 학술발표 논문집
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• pp.324-329
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• 1998

In this paper, neural networks predictive PID (NNPPID) control system is proposed to reduce the vibration of structure. NNPPID control system is made up predictor, controller, and self-tuner to yield the optimal parameters of controller. The neural networks predictor forecasts the future outputs based on present input and output of structure. The controller is PID type whose parameters are yielded by neural networks self tuning algorithm. Computer simulations show displacements of multi-story structures applied to NNPPID system about environmental load-wind forces and earthquakes.

• 대한전기학회논문지:전력기술부문A
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• 제48권4호
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• pp.434-443
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• 1999

In this paper, neural network predictive PID (NNPPID) control system is proposed to reduce the vibration of building structure. NNPPID control system is made up predictor, controller, and self-tuner to yield the parameters of controller. The neural networks predictor forecasts the future output based on present input and output of building structure. The controller is PID type whose parameters are yielded by neural networks self-tuning algorithm. Computer simulations show displacements of single and multi-story structure applied to NNPPID system about disturbance loads-wind forces and earthquakes.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1999년도 추계학술대회논문집
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• pp.363-369
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• 1999

In these days, there are a lot of studies in the port automation, for example, unmanned container trasporter, unmanned gantry crain, and automatic terminal operation systems and so on. In terms of loading and unloading equipments. we can consider container transporter. This paper describes the automatic control for the UCT(unmanned container transporter), especially steering control systems. UCT is now operated on ECT port in Netherland and tested on PSA ports in Singapore. So we present a design on the controller using neural network PID(NNPID) controller to control the steering system and we use the neural network self-tuner to tune the PID parameters. The computer simulations show that our proposed controller has better performances than those of the other.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.48-50
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• 1994

In this paper, the optimal fuzzy controller of exciter and governor in synchronous generator improve the stability of power system with varying loads and disturbances in power system. Parameters of the proposed fuzzy controller were optimally self-tuned by the steepest descent method and were applied to power system stabilization. The related simulation results show that the proposed control technique are more powerful than the conventional ones for reductions of undershoot and for minimization of settling time.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권1호
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• pp.173-187
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• 2022

Recent studies have focused on self-management of hypertension using smart devices (cellular phones, tablets, watches). It has proven to be an effective tool for early detection and control of high Blood Pressure (BP) without affecting patients' daily routines. This systematic review surveys the existing self-monitoring systems, evaluate their effectiveness and compares the different approaches. We investigated the current systems in terms of various attributes, including methods used, sample size, type of investigation, inputs/ outputs, rate of success in controlling BP, group of users with higher response rate and beneficiaries, acceptability, and adherence to the system. We identified some limitations, shortcomings, and gaps in the research conducted recently studying the impact of mobile technology on managing hypertension. These shortcomings can generate future research opportunities and enable it to become more realistic and adaptive. We recommended including more observable factors and human behaviors that affect BP. Furthermore, we suggested that vital monitoring/logging and medication tuning are insufficient to improve hypertension control. There is also a need to observe and alter patient behavior and lifestyles.