• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 추계학술발표대회 개요집
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• pp.144-146
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• 2005

Dual electromagnetic sensor is used for sensing the weld line. The sensor consists of excitation and two sensing coil wound over the ferro-magnetic core. By using the dual sensor, the effect of noise is minimized. It is based on the generation of eddy currents in the welding plate by passing current through the excitation coil. The sensor can be used to track the butt joints having no gap between them, where a vision based sensor fails to track. Sensor sensitivity depends on the number of coil turns, frequency of excitation, distance of a sensor from the work piece, diameter of core, etc. The whole system consists of a sensor, a signal processing board, a motion controller and a personnel computer (PC). The raw sensor signal is processed using the signal processing board. It consists of amplification, rectification, filtering, averaging, offset adjustment, etc. Based on sensor data, the motion controller adjusts the position of a welding torch.

• 대한임베디드공학회논문지
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• 제6권6호
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• pp.369-376
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• 2011

Since wireless sensor networks generally have the capability of network recovery, malfunction of a few sensor nodes in a sensor network does not cause a crucial problem paralyzing the sensor network. The malfunction of the sink node, however, is critical. If the sink node of a sensor network stops working, the data collected by sensor nodes cannot be delivered to the gateway because no other sensor nodes can take the place of the sink node. This paper proposes a TDMA-based wireless sensor network equipped with dual sink nodes, with a view to preventing data loss in the case of malfunction of a sink node. A secondary sink node, which synchronizes with a primary sink node and receives data from other sensor nodes in normal situations, takes the role of the primary sink node in the case of malfunction of the primary sink, thereby eliminating the possibility of data loss. The effectiveness of the proposed scheme is demonstrated through experiments.

• 한국광학회지
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• 제8권2호
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• pp.161-164
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• 1997

편광유지 광섬유를 이용한 주파수가 안정화된, 두 개의 서로 수직으로 편광된 종모우드를 갖는 He-Ne레이저 빛을 LoTa $O_{3}$ 위상변조기로 구성된 센서부(sensor head)로 전달해 줌으로써 원격에서 전기장을 측정할 수 있는 hybrid, heterodyne 간섭식 센서를 구성하였다. In/quadrature-phase위상변조풀이 방식을 이용하여 전기광학 효과에 의해 서로 수직으로 편광된 두 모우드 사이에 유도된 위상차이를 측정함으로써 항상 높은 검지율을 유지할 수 있는 전기장 센서를 구성하고, 이를 이용하여 광학 물질에 유도된 복굴절도 측정을 할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.725-728
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• 1988

Image restoration technique using dual sensor is presented in this paper. Digital Radiography image (1024xlO24) is obtained by conventional resolution sensor. We also obtain local DR image data by high resolution sensor. Two dimensional maximum entropy power spectrum estimation (2-D ME PSE) is applied to low resolution image and high resolution image for the purpose of the power spectrum estimation of each image. A class of linear algebraic restoration filter, parametric projection filter (PPF), is derived from the power spectrums of each image. It is shown that the noise energy may be considerably reduced through the PPF.

• 한국군사과학기술학회지
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• 제20권3호
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• pp.337-344
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• 2017

In this paper, the optical axis alignment(OAA) of an infrared sensor(IRS) using a microwave sensor(MWS) was presented as a method of an axis alignment to minimize the problems that could be caused by the misalignment of the two sensors in the missile including the dual-mode sensor. The azimuth(AZ) and elevation(EL) angles of the two targets used for each sensor test were calculated by using the transformation equation and the test results of the MWS and IRS, and then the proposed OAA was verified by comparing the angles. Furthermore, the validity of the proposed OAA was demonstrated by confirming the abnormality of the OAA through the test results of the electro optical head(EOH) of the IRS which was equipped with a tilt on the missile fuselage.

• 대한기계학회논문집A
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• 제40권8호
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• pp.721-724
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• 2016

실제 사용되는 기계 구조물의 수명 예측은 공정산포, 미래의 하중조건, 손상 모델의 불완전성 등으로 인하여 실험실에서 얻은 결과와 차이를 보일 수 밖에 없다. 본 연구에서는 이러한 불확실성이 내포된 기계 구조물의 피로파괴를 사전에 예지하기 위해 이중센서를 개발하고, 상온에서 단축 피로 하중을 받는 구조물에 적용하여 실증하였다. 이중 센서는 피로하중을 받는 대상 구조물보다 약간 더 큰 응력이 인가되도록 고안된 감지 구조물에 변형률 게이지를 부착한 형태이며, 균열이 센서자체에 먼저 발생함으로써 피로파괴를 예지하며, 쌍으로 제작된 감지부의 변형률 차를 이용하여 변동하중 하에서도 정상상태와 고장상태를 구분이 가능하다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.172-177
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• 1998

An experimental study on the prediction of grinding wheel wear by dual detection methods was conducted by the laser displacement and acoustic emission(AE) system. The laser displacement sensor was located above the head of the grinding wheel and the AE sensor was set under the workpiece, where the wheel were condition can be detected. It was found that the dual detection methods by laser displacement system and AE system made it possible to predict the wheel wear. From the experiments, the root mean square(RMS) values both methods was found to be proportional to the grinding wheel wear.

• International Journal of Advanced Culture Technology
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• 제4권2호
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• pp.27-33
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• 2016

This paper proposes to increase the node energy efficiency, which rapidly drops during the transmission of L-TEEN (Layered Threshold sensitive Energy Efficient sensor Network protocol), using the method of DL-TEEN (Dual-hop Layered TEEN). By introducing dual-hop method in the data transmission, the proposed single-hop method for short-range transmission and multi-hop transmission method between the cluster heads for remote transmission was introduce. By introducing a partial multi-hop method in the data transmission, a single-hop method for short range transmission method between the cluster heads for remote transmission was introduces. In the proposed DL-TEEN, the energy consumption of cluster head for remote transmission reduces and increases the energy efficiency of sensor node by reducing the transmission distance and simplifying the transmission routine for short-range transmission. As compared the general L-TEEN, it was adapted to a wider sensor field.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권5호
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• pp.2063-2081
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• 2018

A resource allocation algorithm is proposed in this paper to simultaneously minimize the total system power consumption and maximize the system throughput for the downlink of multi-user multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems. With the Lagrange dual decomposition method, we transform the original problem to its convex dual problem and prove that the duality gap between the two problems is zero, which means the optimal solution of the original problem can be obtained by solving its dual problem. Then, we use convex optimization method to solve the dual problem and utilize bisection method to obtain the optimal dual variable. The numerical results show that the proposed algorithm is superior to traditional single-objective optimization method in both the system throughput and the system energy consumption.

• 한국전자파학회논문지
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• 제29권11호
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• pp.898-905
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• 2018

본 논문에서는 대지, 대공 표적을 포착 추적할 수 있는 적외선 및 가시광 센서가 탑재된 이종센서 영상탐색기의 종합 성능시험을 위해 구축한 HILS(Hardware In-the-Loop Simulation) 시스템 내에 적외선 표적원을 제안한다. 이 통합시스템은 다양한 종류의 표적과 시나리오 기반 이동 표적의 궤적을 모사하기 위해 열원 및 광원을 출력하는 100개의 모듈로 구성하였다. 또한 표적에 대한 위치, 속도, 방향, 배경 클러터와 재밍 환경 등을 모사할 수 있다. 이종센서 영상탐색기의 시험평가를 위해 구축된 HILS 시스템의 전체 시스템 구성과 적외선 표적원의 설계 및 측정 결과를 제시한다. 향후에, 구축된 HILS 시스템에서 모의비행 시나리오 기반으로 동적 실시간 포착 추적에 대한 단일 또는 이종센서가 탑재된 이종센서 영상탐색기의 성능을 시험할 예정이다.