• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.81-86
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• 2013

In this paper, the parameter identification for localization scheme for the optics-based micro sensor node is conducted. We analyzed short measurement range problem which can be occurred in optical based micro sensor node localization method using a time of flight. And we set up the theory for distance and maximum reflected laser power to overcome the problem by identifying hardware parameters like laser power, effective area of MEMS CCR, sensitivity of photodetector, and so on. Experimental results of measurement of maximum reflected laser power were compared with results of the theory. By using the theory, we can identify hardware parameters of localization scheme to measure particular position of the optics-based micro sensor node.

• IEIE Transactions on Smart Processing and Computing
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• 제3권5호
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• pp.298-305
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• 2014

In this study, a novel Randomly Shifted Certification Authority Authentication protocol was used in ad hoc networks to provide authentication by considering the MAC layer characteristics. The nodes achieve authentication through the use of public key certificates issued by a CA, which assures the certificate's ownership. As a part of providing key management, the active CA node transfers the image of the stored public keys to other idle CA nodes. Finally the current active CA randomly selects the ID of the available idle CA and shifts the CA ownership by transferring it. Revoking is done if any counterfeit or duplicate non CA node ID is found. Authentication and integrity is provided by preventing MAC control packets, and Enhanced Hash Message Authentication Code (EHMAC) can be used. Here EHMAC with various outputs is introduced in all control packets. When a node transmits a packet to a node with EHMAC, verification is conducted and the node replies with the transmitter address and EHMAC in the acknowledgement.

• 전산구조공학
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• 제9권4호
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• pp.141-154
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• 1996

드로네이 요소생성기법은 모델링 영역의 모양에 구애받지 않으면서 요소의 크기제어, 재편성, 국지요소생성 등에 있어서 탁월한 기능을 보여주고 있다. 그러나 생성되는 요소가 선형삼각형요소임으로해서 비압축성 또는 대변위거동의 근사나 복잡한 형상의 영역의 기하학적 근사에 한계를 갖고 있다. 이를 보완하기 위해 기제시된 드로네이 요소생성 알고리즘을 바탕으로한 6절점 삼각요소 생성알고리즘을 제시하여 본 기법의 완성도를 높이고 이를 성형문제에 적용해 보였다.

• Transactions on Control, Automation and Systems Engineering
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• 제3권4호
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• pp.268-271
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• 2001

In this paper, we propose a simplified pollution adaptive mesh generation algorithm using singular elements. The algorithm based on the element pollution error indicator concentrate on boundary nodes. The automatic mesh generation method is followed by either a node-relocation or a node-insertion method. The boundary node relocation phase is introduced to reduce pollution error estimates without increasing the boundary nodes. The node insertion phase greatly improves the error and the factor with the cost of increasing the node numbers. It is shown that the suggested r-h version algorithm combined with singular elements converges more quickly than the conventional one.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1997년도 춘계학술대회 학술발표 논문집
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• pp.259-262
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• 1997

This paper presents a visual servoing of RV-M2 robot manipulators to track and grasp moving object, using pruned dynamic recurrent neural networks(DRNN). The object is stationary in the robot work space and the robot is tracking and grasping the object by using CCD camera mounted on the end-effector. In order to optimize the structure of DRNN, we decide the node whether delete or add, by mutation probability, first in case of delete node, the node which have minimum sum of input weight is actually deleted, and then in case of add node, the weight is connected according to the number of case which added node can reach the other nodes. Using evolutionary programming(EP) that search the struture and weight of the DRNN, and evolution strategies(ES) which train the weight of neuron, we pruned the net structure of DRNN. We applied the DRNN to the Visual Servoing of a robot manipulators to control position and orientation of end-effector, and the validity and effectiveness of the pro osed control scheme will be verified by computer simulations.

• 한국통신학회논문지
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• 제38B권9호
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• pp.751-764
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• 2013

인지무선 애드혹 네트워크(Cognitive Radio Ad-hoc Networks)에서는 노드 간에 라우팅을 수행함에 있어 제어패킷의 전송을 위한 협소대역인 공통 제어 채널을 사용할 경우 무분별한 제어 패킷의 방송형 전송으로 인해 공통제어 채널의 과부화를 유발하고 패킷간의 충돌을 발생시켜 경로탐색의 오버헤드를 증가 시키고 신뢰성을 떨어뜨린다. 본 논문에서는 인지무선 ad-hoc네트워크에서 주사용자의 출현 가능성과 주변 사용자의 상황을 고려하여 패킷충돌을 감소시키는 효율적인 경로 탐색 알고리즘을 제안한다. AODV기반의 인지무선 애드혹 네트워크에서 채널을 통한 경로탐색 과정에서 데이터를 전송하기 위한 이웃 노드와의 공통된 채널이 존재하지 않을 경우 제어 메시지를 전송하지 않는다. 그리고 공통된 채널이 존재 할 경우 채널 기여도를 측정하여 채널 기여도가 작을수록 지연 시킨 후 패킷을 전송하게 된다. 또한 제안된 방법에서는 사용가능한 채널의 수와 채널의 안정성 등을 고려한 규칙을 적용하여 제어 메시지 전송을 조절하도록 한다. 이와 같은 세 가지 단계를 통해 경로 탐색에 사용되는 제어 메시지의 수와 제어 메시지 간의 충돌 확률을 감소시킬 수 있고 경로의 신뢰성을 향상 시킬 수 있다. 모의실험을 통해 기존의 방법 보다 제안된 방법을 이용하여 경로 탐색할 경우 패킷 충돌이 감소됨을 확인 할 수 있었다.

• Toxicological Research
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• 제19권4호
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• pp.285-291
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• 2003

The use of skin whitening agents has been recently increased in various kinds of cosmetic products, although there were some reports that whitening agents might cause allergic contact dermatitis. A murine local lymph node assay (LLNA) has been developed as an alternative to guinea pigs for contact sensitization potential. This study was carried out to investigate the skin sensitization potential of three whitening agents, arbutin, azelaic acid, and kojic acid, by LLNA using a non-radiois-topic endpoint. Female Balb/c mice were exposed topically to a weak allergen, $\alpha$-hexylcinnamalde-hyde (HCA), and three whitening agents following LLNA protocol. Lymph node (LN) weight and cell proliferation in ears and auricular lymph node using bromodeoxyuridine (BrdU) immunohistochemistry were evaluated. LN weights were significantly increased at the HCA group compared to the vehicle control. A weak allergen, HCA elicited 3-fold or greater increase in cell proliferation of lymph nodes as well as increase in cell proliferation of ear as measured by BrdU immunohistochemistry. However, in the case of skin whitening agent groups, there were no significant changes in LN weight and cell proliferation in the ear and lymph node of mice treated with 5, 10 and 20% of three whitening agents compared to the vehicle control. These results show that these three skin whitening agents may not have contact sensitization potentials at tested concentrations in Balb/c mice by LLNA.

• 한국정보통신학회논문지
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• 제10권11호
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• pp.2099-2106
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• 2006

본 논문은 가변의 감지영역을 갖는 무선 센서 네트워크에서 센서노드의 감지에너지 소비를 최소화하기 위한 노드의 위치를 결정하는 방법에 관하여 기술하였다. 감지에너지의 소비를 최소화하기 위해서는 이웃하는 노드들과의 중첩되는 감지면적이 최소화되어야 한다. 중첩영역을 최소로 하는 노드의 위치를 결정하기 위하여, 이웃하는 노드 사이의 감지영역과 전개각 및 각 노드의 감지반경을 이용하여 최적화 식을 유도하였다. 이를 기반으로 한 ASRC(adjustable sensing ranges control)에 의한 새로운 노드 위치방법을 제안하였다. 제 안한 방법은 기존의 조건에 의한 방법과는 달리 수학적 식에 근거하여 유도한 모델로서, 시뮬레이션을 통하여 감지에너지 소모에 대한 유효성을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.657-659
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• 2004

CAN is a serial communication bus for real-time controls and automations in distributed control systems. In distributed control systems, occasionally a sensor module and a controller are not in the same node and physically separated. In order for the signal from a sensor node to reach the controller node, the signal must travel through network. CAN has a certain capabilities to deal with real-time data. However, when many nodes on the networks try to send data on the same network, the arbitration mechanism to solve the data collision problem is necessary. This situation causes the time delay which has detrimental effects on the performance of the control systems. This paper proposes a method to solve the problem due to the time delay in distributed control system using CAN. Time delay is approximated to an element with a rational transfer function using Pade approximation and Mu~synthesis method is applied. Since time delay in the network is not constant, the time delay element is considered to be an uncertainty block with a bound. The proposed method is applied to the experimental system with CAN and proved to be effective.

• 한국자원식물학회지
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• 제11권3호
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• pp.301-306
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• 1998

In order to improve cultivation technuque of C. lanceolata, natural ABA was treated with foliar application periodically during differenctitation of node. The higher is concentration and the earier its foliar application was, the shoter plant height was. Especially, when $10mg;.L{-1}$ of ABA was treated at differentiated stage of 3rd node, plant height was inhibited to 60% of control. But leaf length, leaf width, and number of branches have no significant differnence in comparison wiht control. The fresh weight of subterranean part was similar to control independent of treat-time in the case of $10mg;.L{-1}$. When 1,5 and $10mg;.L{-1}$ of ABA were treated at initial differentiated node stage, plant height inhibited to 20~30% of control, but subterranean part was similar to control. All treatement showed slight antitumor activity by the P388 cytotoxic screening test.