• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.81-89
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• 2009

Recently, Guard lamp was divided from electric facilities for general use as dangerous zone of safety management. This paper presents a remote inspection system of guard lamp that can monitor electrical safety factor. Especially, the developed system adopts the measurement algorithm for detecting resistive leakage current($I_{gr}$) flowing based on the phase difference checkable for sensing at a monitor. Also, It was fabricated the repeater for data transmission and the MMI program At this system, we made experiment on stability of resistive leakage current to verify phase comparison detecting algorism.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.170-176
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• 2004

In this study, the relay driver circuit which controls the spacecraft configuration change are implemented and validated. First of all, the specification of the relay driver circuit is defined, and then its circuit meeting the specification defined is designed. In order to verify the design of the relay driver circuit, its circuit was simulated, and then it's confirmed that the relay pulse current and voltage level defined in the specification are obtained, and the results obtained through the functional test of the relay driver circuit are compared and well matched with the simulation results. Also the worst case analysis for confirming the stable operation of the relay driver circuit under the tolerance of each component is performed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.333-341
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• 2008

A remote sensing technique to identify trajectories of breaking waves in the surf zone using oblique digital nearshore videos is proposed. The noise arising from white foam induced by wave breaking has hindered accurate remote sensing of wave properties in the surf zone. For this reason, this paper focuses on image processing to remove the noise and wave trajectory identification essential for wave property estimation. The nearshore video imagery sampled at 3 Hz are used, covering length scale(100 m). Original image sequences are processed through image frame differencing and directional low-pass image filtering to remove the noise characterized by high frequencies in the video imagery. The extraction of individual wave crest features is conducted using a Radon transform-based line detection algorithm in the processed cross-shore image timestacks having a two-dimensional space-time domain. The number of valid wave crest trajectories identified corresponds to about 2/3 of waves recorded by the in-situ sensors.

• Korean Journal of Remote Sensing
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• v.34 no.3
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• pp.535-543
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• 2018

Recently, level meters have been associated with the safety and maintenance of industrial sites and require a wide measurement range. Generally, to ensure the measurement range of the level meter, the measurement environment is improved to reduce the noise or to compensate the distortion of the signal through signal processing. The noise of FMCW (Frequency Modulated Continuous Wave) radar level meter or the distortion of the signal affects the near region characteristics of the level gauge, resulting in a reduction of the minimum detection distance. In this paper, an equalizer filter considering characteristics of window function and bit spectrum is applied to remove the noise in the near region of the level meter to improve the minimum detection distance performance and to improve the measurement reliability in the vicinity of the level meter, which is relatively difficult to detect, we want to improve the detection range.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.585-590
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• 2012

In this paper, a system using vibrating wire sensor and zigbee wireless network has been implemented to monitor and manage the structure. The implemented strain controller drives vibrating wire sensor and computes strain from measuring frequency of the output signal. Temperature sensor is included to compensate strain by temperature. Using two axis acceleration sensor of strain controller can measure the direction of strain or deformation. To measure strain more effectively, wired and wireless communication function is included in this device. As results of experiments, it is shown that the developed system can be effectively applied to measure strain of the structure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.537-545
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• 2009

Though there were many research and development about telemedicine on land recently, not yet applied to that on the shore. In this paper, when emergency clinic situation were generated in a ship on shore, the telemedicine system was designed and implemented for transfer and clinic service to doctors on the land by measuring basic body signals of patients. Presently, wireless communication and inmarsat telephone are usually used by simple questions and clinic consults to remote doctors when emergency situation were happened in the ship. In this paper, the telemedicine system on the shore were developed for improving this problems by measuring patient's fundamental conditions such as the blood pressure, pulse, the respiratory condition, electrocardiogram, body temperature, patient image and sending these information to remote doctors on land for more accurate prescription. The developed system can supply the high level clinic service to emergency patients on the shore and cope with the emergency situation in ship.

• Korean Journal of Remote Sensing
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• v.14 no.4
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• pp.343-352
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• 1998

Spectral reflectance data of upland crops at OSMI bands were collected and evaluated for the feasibility of crop discrimination knowledge-based on crop calendar. Effective bands and their ratio values for discriminating corn from two other legumes were defined with OSMI equivalent bands and their ratio values. For corn discrimination from two other legumes, peanut and soybean, June 22 among measurements dates was the best since all OSMI equivalent bands and their ratio values in June 22 were highly significant for corn separability. Phenological growth stage of a silage corn (rs510) could be estimated as a function of spectral reflectance in vegetative stage. Five growth stage prediction models were generated by the SAS procedures REG and STEPWISE with OSMI equivalent bands and their ratio values in vegetative stage.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.594-603
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• 2021

This study explored the moderating effects of task difficulty for flow, learning motivation, and interesting in distant PBL classes of pre-service teachers. For this, the research model was constructed by analyzing previous studies. The research model verification was conducted by 105 students of taking courses in the curriculum. The distant PBL used a real-time video conference system. Cooperative activities were carried out in real time. After the end of the distant PBL activity, the level of learning motivation, interesting, flow, and task difficulty perception were measured. The collected data were analyzed using a test of the structural model invariance across the groups using a structural equation model. This analysis verifies the difference in path coefficients between measurement models. The control effect of task difficulty was verified through the difference in path coefficient. As a result, it was verified that interesting mediates the influence of learning motivation on flow. And the moderating effect of the perceived task difficulty appeared on the path from learning motivation to interesting.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.121-129
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• 2009

Inspection of an Electrical Meter is an action of measuring power usage to charge electricity rates and Electricity AMR(Automatic Meter Reading) is a system to automatize the action. AMR has been highlighted because it can reduce metering cost by substituting an automatic system for personnel and strengthen customer service. In this paper, we proposed and developed a smart card based AMR framework SCEMS as an alternative to other current AMR Models. This proposed SCEMS uses a java card based multi-application smart card and supports customer service such as various meter rates according to electricity consumption pattern data per household and transaction data that are accumulated in a smart card. This research can be a solution to the problems such as diversity, heterogeneity, and complexity that environmental changes will cause soon to the power supply industry.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06d
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• pp.204-207
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• 2007

최근 대두되고 있는 무선 센서네트워크는 실생활의 많은 부분에 있어 그 응용 분야를 넓혀 가고 있다. 본 연구는 WSN의 응용 중 Human Health Care에 주안을 두어 WSN을 이용한 원격 진료 시스템에 대해 설계 및 구현을 하였다. 원격 진료 시스템을 위해 각 센서 노드들은 인체의 Body 정보를 수집할 수 있는 센서들을 가지고 신체의 각 부위에 부착된다. 또한 각 센서 노드들은 고유의 Human Body Code를 가지고 있으며 이 고유의 Code에 의해 인체의 어느 부위에서 측정된 Data인지를 Sink 노드로 전송하게 된다. Sink 노드는 수집된 정보를 원격에 위치한 의료진들에게 전송하며 원격의 의료진들은 Sink 노드에서 전송된 정보를 바탕으로 진료 정보를 환자 및 User에게 Feedback하게 된다. Human Body Code는 인체를 세분화하고 각 세분화한 신체 부위에 계층적으로 고유의 Code를 부여한다. 본 연구에서는 실제 Human Body Code를 직접 제작한 센서 Node에 주입하여 Human Body Network을 구성하여 인체에서 센싱되는 Data를 원격에 위치한 PC에서 진료 가능한 원격 진료 시스템을 구현하였다.