• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2206-2207
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• 2008

본 논문에서는 분전반에서의 화재 위험 요소와 화재위험 요소에 대한 현장 실태조사 결과를 분석하였다. 분전반에서의 화재 위험 요소는 크게 전기적 요인, 환경적 요인, 물리적 요인으로 나눌 수 있으며 전기적 요인으로는 단락, 과부하(과전류), 접촉불량, 전류 불평형 등이 있으며 환경적 요인으로는 수분(염분 등), 먼지(분진, 목분, 철분 등), 온도(고온) 등에 의한 절연파괴, 기기 손상, 오동작 등이 있다. 물리적 요인으로는 기계적인 진동이나 충격 등에 의한 전기적 접속부의 이완에 의한 발열 등을 들 수 있다. 이러한 화재 위험 요인에 대하여 현장실태조사를 실시한 결과, 일부 분전반에서 내부에 먼지 등 이물질이 차단기, 전선, 단자대 등의 표면에 부착되어 있음을 확인할 수 있었으며 수분이나 염분 등의 영향으로 전극간 절연물 표면의 열화로 화재가 발생할 가능성이 있다. 또한, 적외선 열화상 분석결과, 일부 차단기 단자에서 국부 발열이 관측되었으며, 부하 분담의 불평형에 의한 발열도 확인되었다. 이러한 위험요인에 의한 화재 예방을 위하여 규정된 전선 굵기의 사용과 적정 체결압력의 확보, 상간 전류 불평형을 줄이기 위한 부하 분담의 조정이 필요하다. 향후, 분전반에서의 전기화재, 감전사고 등 전기재해의 예방을 위하여 지속적이고 체계적인 유지관리는 물론 사고 발생 전에 이상 징후를 사전에 감지하여 조치를 취할 수 있도록 하는 기술의 개발과 현장 적용이 요구된다.

• Aerospace Engineering and Technology
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• v.12 no.2
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• pp.14-23
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• 2013

Fault management design of the satellite describes preparations for failures which can occur during operational phase. Fault management design contains detection and isolation function of anomaly, and also it contains function to maintain the satellite in safe condition until the ground station finds out a cause of failure and takes a countermeasure. Unlike normal operation, safing operation is automatically performed by Power Control and Distribution Unit and Integrated Bus Management Unit which loads Flight Software without intervention of ground station. Since fault management operation is automatical, fault management logic and functionality of relevant hardware should be thoroughly checked during ground test phase, and error which is similar to actual should be carefully applied without damage. Verification test for fault management design is conducted for various subsystems of satellite. In this paper, we show the design process of fault management design verification test for Electrical Power Subsystem and Attitude and Orbit Control Subsystem of Low Earth Orbit satellite flight model and the test results.

• Journal of Korean Society for Geospatial Information Science
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• v.11 no.2 s.25
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• pp.53-59
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• 2003

Many facilities have been constructed due to the rapid development of science and economy, and the tendency for larger sizes and higher stories in constructing are being accelerated due to the development of technologies, and the efficient use of limited spaces. The safety problems of constructions are being frequently brought up. So, a technique by which the monitoring of the safety of constructions can be easily done must be developed as soon as possible. In this research an management system for structure's displacement using satellite survey was studied. The results of having established the management system for structure's displacement as a GPS positioning system were that data acquisition was easier than that from using normal survey equipment, and data from the satellite survey can be applied to the database of management system. The data of the GPS suey were rather large values to determine the safety of single stories, but can probably be used in establishing the management system using the structure's displacement.

• Composites Research
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• v.28 no.4
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• pp.148-154
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• 2015

In order to detect damage in early stages and properly maintaining structures, the structural health monitoring technology is employed. In most cases, active-sensing SHM needs many piezoelectric (PZT) sensors and actuators. Thus, if there is a defect on PZT used for active-sensing SHM, the structural status could be misclassified. This study, for reliable SHM performance, investigated to detect defects of sensors by using the admittance-based sensor diagnostics. This study also introduced an algorithm that can diagnose sensor defects based only on data measured from the sensors in case that information about the changes in adhesive and environmental investigation, this study confirms that the proposed algorithm could be efficiently applied to real-world structures in which a significant temperature variation could take place.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.211-220
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• 2018

The standard data link layer encryption provided by CCSDS has a structure that encodes HDLC frame into it using an AES algorithm. However, CCSDS is standard method has a structure in which the receiving side cannot request a re-activation when noise interference occurs over an unstable channel. SES Alarmed has a structure that enables the receiving side to additionally detect errors and perform re-activation requests in an operational structure similar to that of link encryption in CCSDS. The SES Alarmed related paper was intended to identify the optimum range of thresholds and identify data corruption due to channel noise. In this paper, the focus was on reducing the re-activation process if the HDLC frame, excluding the password Sync code, consistently exceeds any threshold levels. The HDLC frame order was changed and the results of using SES Alarmed were proposed and compared.

• Composites Research
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• v.31 no.6
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• pp.429-434
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• 2018

We investigate strain transmissions of a surface bonded distributed optical fiber sensor considering strain variation according to positions. We first derive a strain transmission ratio depending on a wavelength of a strain distribution of the host structure from an analysis model. The strain transmission ratio is compared with numerical results obtained from the finite element method using ABAQUS. We find that the analytical results agree well with the numerical results. The strain transmission ratio is a function of a wavelength, i.e. the strain transmission ratio decreases (increases) as the wavelength of the host strain decreases (increases). Therefore, if an arbitrary strain distribution containing various wavelengths is given to a host structure, a distorted strain distribution will be observed in the distributed optical fiber sensor compare to that of the host structure, because each wavelength shows different strain transmission ratio. The strain transmission ratio derived in this study will be useful for accurately identifying the host strain distribution based on the signal of a distributed optical fiber sensor.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1347-1356
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• 2022

In this paper, we investigate the properties of CoGe thin film-based galvanic cells as a function of their dimension (cell length, width, etc.) and show their application as sensors to Arduino-based IoT sensor networks to detect water contact. Because these CoGe thin film-based galvanic cells do not require mechanical strains or temperature gradients unlike piezoelectric and thermoelectric energy harvesters, we think that these thin film-based galvanic cells are more suitable for self-powered sensor networks demanding sustainable and robust energy harvesters. In the past, a sputter-deposited CoGe thin film has not been intensively investigated for energy harvesting appilcations. Thus, in this study, we perform a feasibility study of galvanic cells composed of a sputter-deposited CoGe thin film to see if they can be applied as potential self-powered sensors. We believe that this paper will be of great help in developing even more enhanced sensor networks.

• 한국노년학
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• v.39 no.4
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• pp.883-893
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• 2019

The purpose of this study is to analyze the characteristics of the elderly patients with depression who were admitted to the hospital with intentional self-harm. 3,280 patients were selected from KCDC database(2011-2015) using STATA 12.0. Analysis results show that gender(female), residence(micropolitan city), result of suicide(death), risk factors(financial problems, psychological problems, physical disease, conflicts with family, place(non-residence) method of suicide(poisoning) were statistically significant. The hospital should detect the elderly patient with depression when they admitted.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.685-686
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• 2023

상수도관의 수질 및 부식도 검사에는 파이프에 손상을 입히지 않고 지속적인 방법이 필요하다. 초음파는 이를 만족하면서 상태를 확인할 수 있고 주파수가 높을수록 해상도가 좋아져 정밀한 측정이 가능하다는 장점이 있다. 이러한 특성을 이용해 상수도관 모니터링 시스템으로 초음파 기반의 Scanning Acoustic Microscopy(SAM)과 Convolutional Neural Network(CNN)을 사용하는 새로운 방법을 제안한다. 기존의 Non-Destructive Testing(NDT)방식의 단점을 보완하면서 더 높은 해상도로 상수도관을 점검하는 방식으로, SAM 을 이용하여 부식으로 인한 파이프 두께 변화와 부유물의 여부 및 수질을 동시에 감지하고 얻은 데이터를 CNN 으로 분석했다. CNN 의 높은 정확도 결과로 이 시스템의 파이프 부식도 및 수질 모니터링에 대한 적합성을 보여주었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.4
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• pp.374-381
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• 2024

This paper delves into the application of the short-wave infrared (SWIR) region, with a focus on the synthesis and optical characteristics of silver sulfide (Ag₂S) nanostructures. SWIR offers advantages such as reduced damage to biological tissues and enhanced optical transparency, making it valuable across various domains. The study introduces three distinct synthesis methods, each showcasing the ability to obtain nanostructures with improved optical properties. These research findings open up the possibility of providing tailored solutions in detection, imaging, and other applications by controlling the size and ligands of Ag₂S nanoparticles. This paper provides new insights into the utilization of Ag₂S in the SWIR region, which is expected to foster advancements in future technologies.