• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1107-1112
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• 2002

An easy elevator originated is an opened system to compare an existing equipment, and learning efficient is high as a wiring that the sequence control circuit is on and off. The structure of an equipment to be controled from the first floor to the fifth floor is constructed by a lamp to express the function of the open-close of the door according to the cage moving, to express the mechanical actuation of the forward-reverse break and motor of load and of hand-worked control component of Push-Button S/W, L/S and Relay. In order to act of the elevator function that these components connected, designed the auto program and the sequence control circuit. Consequently the process that these(1~5steps) operated the cage with an auto program of the elevator and the sequence control circuit is controled by the step of forward and reverse that the L/S1~L/S5 of sensor adjust function let posit, by the adjustable S/W1~S/W5 of PLC testing panel and the S/W1~S/W5 which installed on the transparent acryl plate of a frame. In here, improved apparatus is the learning equipment of combined use to study the principle and the technique of the originated sequence control circuit and the auto program of PLC.

• 한국기계가공학회지
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• 제13권3호
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• pp.28-34
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• 2014

In this paper, we propose a trajectory tracking controller for a two-wheeled mobile robot (WMR) with nonholonomic constraints using a fuzzy sliding-mode controller-based hyperbolic function. The proposed controller is composed of two separate controllers. The sliding-mode controller is used for attitude control of the WMR, and the fuzzy controller-based hyperbolic function is designed to adjust the reach time of the sliding-mode control. Simulation results on a linear and a circular trajectory show that the proposed controller improves the control performance. The proposed controller reduces the reach time by as much as 47% compared to the controller proposed by Xie et al.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3245-3271
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• 2016

To obtain well-dehazed images at the receiver while sustaining low bit rates in the transmission pipeline, this paper investigates the effects of image dehazing methods using dehazing contrast-enhancement filters on image compression for surveillance systems. At first, this paper proposes a novel image dehazing method by using a new method of calculating the transmission function—namely, the direct denoising method. Next, we deduce the dehazing effects of the direct denoising method and image dehazing method based on dark channel prior (DCP) on image compression in terms of ringing artifacts and blocking artifacts. It can be concluded that the direct denoising method performs better than the DCP method for decompressed (reconstructed) images. We also improve the direct denoising method to obtain more desirable dehazed images with higher contrast, using the saliency map as the guidance image to modify the transmission function. Finally, we adjust the parameters of dehazing contrast-enhancement filters to obtain a corresponding composite peak signal-to-noise ratio (CPSNR) and blind image quality assessment (BIQA) of the decompressed images. Experimental results show that different filters have different effects on image compression. Moreover, our proposed dehazing method can strike a balance between image dehazing and image compression.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권5호
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• pp.896-909
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• 2010

IEEE 802.11 medium access control (MAC) employs the distributed coordination function (DCF) as the fundamental medium access function. DCF operates with binary exponential backoff (BEB) in order to avoid frame collisions. However it may waste wireless resources because collisions occur when multiple stations are contending for frame transmissions. In order to solve this problem, a binary negative-exponential backoff (BNEB) algorithm has been proposed that uses the maximum contention window size whenever a collision occurs. However, when the number of contending stations is small, the performance of BNEB is degraded due to the unnecessarily long backoff time. In this paper, we propose the adaptive BNEB (A-BNEB) algorithm to maximize the throughput regardless of the number of contending stations. A-BNEB estimates the number of contending stations and uses this value to adjust the maximum contention window size. Simulation results show that A-BNEB significantly improves the performance of IEEE 802.11 DCF and can maintain a high throughput irrespective of the number of contending stations.

• 융합신호처리학회논문지
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• 제12권1호
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• pp.56-61
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• 2011

많은 제어기법들이 제어계의 제어성능을 개선하기 위해 제안되고 있다. 제어계에서 제어에 대한 자유도는 독립적으로 조정할 수 있는 페루프 전달함수의 수로 결정된다. 목표치 추종 및 외란억제에 2자유도 제어기법이 많이 이용되고 있다. 본 논문에서는 PID 제어기를 2자유도 제어기법을 이용하여 제어계를 설계할 수 있는 정규화법을 제안하였다. 제안한 설계법은 제어대상의 전달함수의 계수값을 이용하여 계의 전달함수를 정규화 하고, 제어기의 계수들이 결정되도록 하였다. 이 방법으로 설계된 제어계를 이용하여 2자유도 제어계를 구성하였고, 시뮬레이션 결과를 통하여 제안한 알고리즘의 유효성을 확인 하였다.

• 대한조선학회논문집
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• 제31권2호
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• pp.38-44
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• 1994

1960년대 Auto-Pilot 시스템이 대양을 항해하는 선박에 장착되면서 운항경제성 및 선원 승선감의 견지에서 Auto-Pilot시스템의 제어 알고리듬이 연구되기 시작하였다. 초기에는 PD제어로 시작하였으나 잦은 타동작으로 인한 기구 마모를 줄이기 위해 실제 선수각과 설정선수방위 차가 어느 상한치 이상에서만 타각을 조작하는 on-off 제어를 도입하였다. 본 논문에서는 Auto-Pilot 시스템의 제어 알고리듬에 optimal제어, adaptive제어 등을 적용하여 제어기법간의 비교를 cost function을 통하여 수행함으로써 Auto-Pilot 시스템에 대한 최적의 제어기법을 조사하였다. Adaptive 제어를 위한 선박 조종운동방정식의 parameterization 과정을 검토하였고 adaptive 알고리듬의 장점이 파라미터 추정이 잘못된 경우의 수치시뮬레이션 결과로부터 분명히 알 수 있었다.

• 한국콘텐츠학회논문지
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• 제9권5호
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• pp.91-98
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• 2009

최근 디지털카메라의 기술 개발은 빛이 부족한 상황에서도 사진용 플래시와 같은 장비를 사용하지 않고서 사진을 촬영할 수 있는 다양한 고감도 기능을 탑재하는 경향이다. 또한 다양한 고감도에 적용시킬 수 있는 디지털카메라의 노이즈감소기능도 동시에 개발되고 있다. 그러나 노이즈가 발생하기 쉬운 고감도 상황에서 디지털카메라의 노이즈감소기능은 노이즈를 감소시키는 동시에 이미지의 해상도도 감소시키는 경향을 보인다. 따라서 본 연구에서는 디지털카메라의 노이즈감소기능이 이미지 해상도에 미치는 영향을 실험을 통해 양적으로 수치화 하고자 한다. 실험은 해상도와 노이즈 타깃을 디지털카메라의 감도별로 촬영하고, 측정값을 분석한 결과 노이즈감소기능이 적용될 때 최대 15%까지 해상도가 감소하는 것을 확인할 수 있었다. 이와 같은 연구는 디지털카메라의 사용자에게는 노이즈감소기능의 정확한 활용을 가능하게 하며 제조사에게는 노이즈감소기능을 검증해 볼 수 있게 할 것이다.

• 한국항만학회지
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• 제15권1호
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• pp.37-46
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• 2001

Fuzzy logic control(FLC) is composed of three parts : fuzzy rule-bases, membership functions, and scaling factors. Well-defined fuzzy rule-base should contain proper physical intuition on the plant, so are needed lots of experiences of the skillful expert. When membership functions are considered, some parameters on the memberships function such as function shape, support, allocation density should be selected well. The rule of scaling factors is 'scaling'(amplifying or reducing) for both input and output signals of the FLC to fit in the membership function support and to operate the plant intentionally. To get a better performance of the FLC, it is necessary to adjust the parameters of the FLC. In general, the adaptation of the scaling factors is the most effective adjustment scheme, compared with that of the fuzzy rule-base or membership function parameters. This study proposes the adaptation scheme of the scaling factors. When the adaptation is performed on-line, the stability of the adaptive FLC should be guaranteed. The stable FLC system can be designed with stability analysis in the sense of Lyapunov stability. To adapt the scaling factors for the error signals, the concept of the conventional MRAC would be introduced into slightly modified form. A tracking accuracy of the control system would be enhanced by the modified shape and support of the membership function. The simulation is achieved on the pilot plant with the hydraulic steering control of a UCT(Unmanned Container Transporter) of which modeling dynamics have lots of severe uncertainties and modeling errors.

• 융합정보논문지
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• 제12권3호
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• pp.259-269
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• 2022

본 연구는 배우자 사별을 경험한 여성 노인을 대상으로 우울이 삶의 만족도에 미치는 영향에서 가족기능의 매개효과를 파악하기 위한 서술적 조사연구이다. 본 연구는 2021년 3월부터 4월까지 A시에 거주하는 배우자 사별경험이 있는 60세 이상 여성 노인 192명을 대상으로 자료 수집하였다. 자료 분석은 SPSS 27.0 Statistics Program을 이용하였으며, 우울과 삶의 만족도와의 관계에서 가족기능의 매개효과를 분석하기 위하여 계층적 다중회귀분석(Hierarchical Multiple Regression) 방법으로 분석하였다. 연구결과 배우자 사별을 경험한 여성 노인의 우울이 삶의 만족도에 미치는 영향에서 가족기능이 완전매개 효과가 있음을 확인하였다. 본 연구결과를 바탕으로 배우자와의 사별을 경험한 여성 노인의 원만한 적응을 돕기 위해 가족기능을 향상 시킬 수 있는 다양한 프로그램 개발과 적용이 필요하다.

• 전자공학회논문지B
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• 제31B권7호
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• pp.170-178
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• 1994

The nearest neighbor classification rule is widely used because it is not only simple but the error rate is asymptotically less than twice Bayes theoretical minimum error. But the method basically use the whole training patterns as the reference vectors. so that both storage and classification time increase as the number of training patterns increases. LVQ(Learning Vector Quantization) resolved this problem by training the reference vectors instead of just storing the whole training patterns. But it is a heuristic algorithm which has no theoretic background there is no terminating condition and it requires a lot of iterations to get to meaningful result. This paper is to propose a new training method of the reference vectors. which minimize the given error function. The nearest neighbor network,the network version of the nearest neighbor classification rule is proposed. The network is funtionally identical to the nearest neighbor classification rule is proposed. The network is funtionally identical to the nearest neighbor classification rule and the reference vectors are represented by the weights between the nodes. The network is trained to minimize the error function with respect to the weights by the steepest descent method. The learning algorithm is derived and it is shown that the proposed method can adjust more reference vectors than LVQ in each iteration. Experiment showed that the proposed method requires less iterations and the error rate is smaller than that of LVQ2.