• Journal of Biosystems Engineering
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• v.36 no.5
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• pp.319-325
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• 2011

This study was conducted to figure out the diagnosis basis of cooling performance depending on water amount in the refrigerant of air conditioner, which can be estimated by the temperatures and pressures along the refrigerant circulation line. A car air conditioner of SONATA III (Hyundai motor Co., Korea) was tested at maximum cooling condition at the engine speed of 1500 rpm in the room controlled at 33~$35^{\circ}C$ air temperature and 55~57% relative humidity conditionally. Measured variables were temperature differences between inlet and outlet pipe surfaces of the compressor, condenser, receive drier and evaporator; and high pressure and low pressure in the refrigerant circulation line; and temperature difference between inlet and outlet air of the cooling vent of evaporator. In this study, changes of the water amount in the refrigerant were correlated to the temperatures and pressure changes and also water amount caused poor cooling performance. As water amount increased in the refrigerant in the air conditioner, the performance of the cooling or the heat transfer became worse. Temporal variations of the surface temperature of the evaporator outlet pipe and the low-side pressure showed various patterns that could estimate the water amount. When the water amount caused bad cooling performance, the patterns of the temperature of the evaporator outlet pipe indicated irregular fluctuation greater than $5^{\circ}C$. When the diagnosis system is using just external sensors of the low-side pressure and the temperatures of inlet and outlet air of cooling vent of the evaporator, the precise pattern of bad cooling performance caused by excess water amount in the cooling line was irregular pressure fluctuation, 25 kPa under 120 kPa, and temperature, $12^{\circ}C$ and less.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.75-81
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• 2007

This paper dealt with the design and implementation of an expert system to monitor and diagnose the lightning arresters in GIS substations. The expert system consists of a data acquisition module(DAM) based on microprocessor and diagnostic algorithms. The DAM measures and analyzes several parameters necessary for the arrester diagnosis such as system voltages, leakage current components, and temperatures. Also, it includes an intelligent surge counter which can record the date and tin, the polarity, and the amplitude of surge currents. All the data acquired is transmitted to a remote computer by a low rate wireless network specified in IEEE 802.15.4 to avoid electromagnetic intereference under high voltage and large current environments. The decision-making for the arrester diagnosis completes with a Java Expert System Shell(JESS) which is composed of a knowledge base, an inference engine and a graphic user interface(GUI).

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.600-602
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• 2006

Some abnormal signals diagnostics and analysis through an important equivalent circuits modeling for passive elements under severe accident conditions have been performed. Unlike the design basis accidents, there are inherently some uncertainties in the instrumentation capabilities under the accident conditions. So, the circuit simulation analysis and diagnosis methods are used to assess instruments in detail when they give apparently abnormal readings as an accident alternative method. The simulations can be useful to investigate what the signal and circuit characteristics would be when similar to a variety of symptoms that can result from the environmental conditions such as high temperature, humidity, and pressure condition. In this paper, a new simulator through an analysis of the important equivalent circuits modeling under temperature accident conditions has been designed, the designed simulator is composed of the LabVIEW code as a main tool and the out-put file of the Multi-SIM code as an engine tool is exported to in-put file of the LabVIEW code. The procedure for the simulator design was divided into two design steps, of which the first step was the diagnosis method, the second step was the circuit simulator for the signal processing tool. It has three main functions which are a signal processing tool, an accident management tool, and an additional guide from the initial screen. This simulator should be possible that it could be applied a output signal analysis to some transient signal by variation of the resistance passive elements in the R-L-C equivalent circuit modeling under various degraded conditions in NPPs.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1439-1443
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• 2011

Bimodal Tram is the new conceptual and environmental-friendly public transportation which adopted series hybrid system. The generator driven by CNG engine supplies the electric power to Battery and traction motor. The generator installed on the vehicle will experience the mechanical vibration and electrical transient variation. Those may cause some defects on the generator which will be the hazardous effects to the vehicle. This paper has investigated the possibility to find out some diagnostic features for the defects of generator through the voltage and current generated from it. Those were analyzed in both time and frequency regions. For the next, more works will be needed to complete the purpose of this paper.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.99-104
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• 2011

Pilots are exposed to carcinogenic substances like radiation, ozone, exhaust gas from jet engine, and electromagnetic wave, their environment can be very hazardous. I designed this study to know if there is any difference between pilots and general people in cancer incidence. I analyzed cancer cases between 1999 and 2008, and investigated their age, site, aircraft types, and sex. I compared pilot's cancer incidence with general people during same periods. Statistical analysis was performed with standardized incidence ratio (SIR). 10 cases were high performance pilots, 5 cases were low performance pilots. The average age when the diagnosis had been made was $39{\pm}7.8$. Pilot's incidence ratio was lower than people's, the most common cancer was kidney, and there was no lung cancer. Cancer is influenced by gene and environment, each country has different patterns. The low incidence ratio in Korean pilots might be due to "healthy worker effect". I think we should perform further investigation on kidney cancer.

• Journal of Multimedia Information System
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• v.6 no.4
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• pp.303-308
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• 2019

The personal health record platform can store and manage medical records, health-monitoring data such as blood pressure and blood sugar, and life logs generated from various wearable devices. It provides services such as international standard-based medical document management, data pattern analysis and an intelligent inference engine, and disease prediction and domain contents. This study aims to construct a foundation for the transmission of international standard-based medical documents by mapping the diagnosis items of a general health examination, special health examination, life logs, health data, and life habits with the international standard terminology systems. The results of mapping with international standard terminology systems show a high mapping rate of 95.6%, with 78.8% for LOINC, 10.3% for SNOMED, and 6.5% when mapped with both LOINC and SNOMED.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.12 no.1
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• pp.80-92
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• 2008

Background: The consequences of disordered breathing patterns are not only distressing to the patient but also expensive to our health care systems if they are not diagnosed and treated. So we performed this study to investigate clinical significants trough gigong, yoga and hyperventilation in oriental medicine and westen medicine Objective: To review the relationship of electrogastrography with autonomic nervous system and to study its clinical application. Method: We investigate the research results through internet search engine, Pubmed. Conclusion: Electrogastrography is a reliable, non-invasive method for recording gastric myoelectrical activity and is used for objectification of diagnosis related to gastric peristalsis. Gastric myoelectrical activity seem to involve autonomic nervous system, especially parasympathetic nervous system. The study should be continuing about relationship between electrogastrography and autonomic nervous system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.321-324
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• 2013

디젤엔진에서 노킹 현상은 엔진의 성능 및 수명에 직접적인 영향을 주는 중요한 인자이며, 엔진 밸런스 또한 엔진 출력 및 내구성에 직접적인 영향을 미치는 중요한 인자이다. 따라서 노킹 진단 및 엔진 밸런스 보정 알고리즘을 적용하여 ECU를 최적화 하고자 한다. 또한 OBD-II 표준을 사용하여 차량 위주의 진단기를 개발하여 운전자 중심의 진단 서비스를 제공하며, 자동차 고장진단 신호 및 센서 출력 신호를 실시간 통신이 제공 될 수 있게 한다. 이를 위해 자동차 고장진단 신호 및 센서출력 신호를 유선시스템과 무선 시스템인 블루투스 모듈을 이용하여 실시간 통신이 제공 될 수 있는 OBD-II 진단기 S/W를 설계 및 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.220-222
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• 2006

분산 어플리케이션은 동시에 여러 사용자가 각기 다른 환경에서 동기화된 프로세서를 사용하기 때문에 일정 한 성능을 유지하는 것이 무엇보다 중요하다. 진단엔진은 시스템을 진단하여 시스템 결함의 원인을 발견하여 시스템이 자가치료가 가능하게 한다. 적응형 미들웨어는 진단엔진을 사용해서 분산 어플리케이션이 로컬환경에 맞는 고른 서비스를 유지 할 수 있도록 한다. 본 논문은 베이지안 네트워크를 사용한 적응형 미들웨어의 진단엔진을 제안한다. 베이지안 네트워크는 상황인지분야에서 널리 사용되는 추론기법으로서, 수집 된 데이터를 통해서 그 구조를 학습하고 데이터를 증거 값으로 시스템 진단을 한다. 본 논문은 실험 대상자로부터 윈도우시스템에서 두 시간 동안 데이터를 수집하여 한 시간은 베이지안 네트워크 학습에 사용하고, 나머지는 베이지안 네트워크 성능평가에 사용하였다. 실험 결과 학습된 두 개의 베이지안 네트워크 모델은 각각 95.41%, 99.77%의 정확성을 보였다.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.410-413
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• 1998

A passive approach for enhancing fault detection and isolation performance of multiple observer based fault detection isolation schemes(FDIS) is proposed. The FDIS has a hierarchical framework to perform detection and isolation of faults of interest, and diagnosis of process faults. The decision unit comprises of a rule base and fuzzy inference engine and removes some difficulties of conventional decision unit which includes crisp logic and threshold values. Emphasis is placed on the design and evaluation methods of the diagnostic rule base. The suggested scheme is applied for the FDIS design for a DC motor driven centrifugal pump system.