• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.735-742
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• 2017

In this study, an effective model-based sensor fault detection methodology that can detect and isolate PEM temperature sensors fault is introduced. In fuel cell vehicle operation process, the stack temperature affects durability of a fuel cell. Thus, it is important for fault algorithm to detect the fault signals. The major objective of sensor fault detection is to guarantee the healthy operations of the fuel cell system and to prevent the stack from high temperature and low temperature. For the residual implementation, parity equation based on the state space is used to detect the sensors fault as stack temperature and coolant inlet temperature, and residual is compared with the healthy temperature signals. Then the residuals are evaluated by various fault scenarios that detect the presence of the sensor fault. In the result, the designed in this study fault algorithm can detect the fault signal.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.613-619
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• 2016

A pneumatic control valve performs a major role in controlling the flow of a system or the level of a key tank in many power plants, and its performance should be guaranteed during the plant's lifetime. Its operation starts by supplying air to the pneumatic actuator or by exhausting the air from the actuator. To control the valve position, the amount of air supply or exhaust is adjusted by a control loop where various accessaries are equipped. In this paper, air leakage in the air supply line, changes in the valve packing force, and false adjustments of zero and the span of the positioner are simulated and analyzed using a 2-in pneumatic valve with a position control loop including an I/P converter and positioner, where the valve position is controlled within ${\pm}2%$ of the control pressure at 67% opening position.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1333-1342
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• 2018

Until now, Electroencephalography(: EEG) has been the most important and convenient method for the diagnosis and treatment of epilepsy. However, it is difficult to identify the wave characteristics of an epileptic EEG signals because it is very weak, non-stationary and has strong background noise. In this paper, we analyse the effect of dimensionality reduction methods on Epileptic EEG feature selection and classification. Three dimensionality reduction methods: Pincipal Component Analysis(: PCA), Kernel Principal Component Analysis(: KPCA) and Linear Discriminant Analysis(: LDA） were investigated. The performance of each method was evaluated by using Support Vector Machine SVM, Logistic Regression(: LR), K-Nearestneighbor(: K-NN), Decision Tree(: DR) and Random Forest(: RF). From the experimental result, PCA recorded 75% of highest accuracy in SVM, LR and K-NN. KPCA recorded 85% of best performance in SVM and K-KNN while LDA achieved 100% accuracy in K-NN. Thus, LDA dimensionality reduction is found to provide the best classification result for epileptic EEG signal.

• The Journal of Sustainable Design and Educational Environment Research
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• v.18 no.1
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• pp.38-48
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• 2019

The purpose of this study is to present a more effective daily checklist than the formal routine check before the experiment to prevent accidents in the university laboratory. To do this, we reconstructed the current daily checklist and previous research data and conducted a second Delphi survey. As a result, there were four general safeties such as arranging the laboratory, three mechanical safeties such as abnormal condition of machine and tool tightening parts, three electric safeties such as prohibition of loading around the electric distribution panel, six chemical safeties such as handling and managing harmful factors, three items of fire safety such as fire extinguisher inspection, five cases of gas safety gas container inspection, one item of biological safety such as the state of hand sterilizer management and one other item, which were provided in the daily checklist as twenty six categories in total. According to the opinions of related experts, it is necessary to have an easy and simplified daily checklist for actual daily checkups.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.2
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• pp.185-195
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• 2018

As machines have been automated in the field of industries in recent years, it is a paramount importance to manage and maintain the automation machines. When a fault occurs in sensors attached to the machine, the machine may malfunction and further, a huge damage will be caused in the process line. To prevent the situation, the fault of sensors should be monitored, diagnosed and classified in a proper way. In the paper, we propose a sensor fault detection scheme based on SVM and CNN to detect and classify typical sensor errors such as erratic, drift, hard-over, spike, and stuck faults. Time-domain statistical features are utilized for the learning and testing in the proposed scheme, and the genetic algorithm is utilized to select the subset of optimal features. To classify multiple sensor faults, a multi-layer SVM is utilized, and ensemble technique is used for CNN. As a result, the SVM that utilizes a subset of features selected by the genetic algorithm provides better performance than the SVM that utilizes all the features. However, the performance of CNN is superior to that of the SVM.

• Journal of Korean Public Health Nursing
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• v.5 no.1
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• pp.53-69
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• 1991

가정간호사업 도입에 대한 대상자의 필요성에 대한 인식을 알아보고자, 1988년 7월 1일부터 동년 8월말까지 서울시내 5개 대학병원에서 퇴원하는 환자 390명과 환자 보호자 380명, 주민 780명, 총 1550명을 대상으로 조사한 결과 다음과 같은 결론을 얻었다. 1. $81\%$의 대상자가 가정간호 사업 도입이 필요하다고 한 반면 $7.5\%$는 필요 없다고 하였으며, $11.5\%$는 잘 모르겠다고 하였다. 필요성 인식 율은 주민이 $83\%$, 환자보호자가 $79\%$, 환자가 $78\%$로서 세 집단 간에 유의한 차이 가 있었다. (P<.01). 인구학적 변수별로 보았을 때, 교육수준과 가정수입에 따라 인식 율에는 유의한 차이가 있어서 (P<.001, P<.01), 교육수준이 높을수록, 수입이 많을수록 높았다. 2. 필요성 인식 율은 가정간호사업 이용의사에 따라서도 유의한 차이가 있어서 (P<.001), 이용의사가 많은 군이 인식 율도 높았다. 3. 환자들의 필요성 인식 율은 퇴원시기에 대한 의견과 병원비 지출액에 따라 유의한 차이가 있어서 (P<.05, P<.02), 퇴원시기가 적절하다는 군이 부적절, 하다는 군보다, 또한 병원비 지출액이 적을수록 인식 율이 높았다. 진단명에 따라서는 피부 및 피하조직 진환$(100\%)$, 임신 및 출산에 관련된 합병증$(90\%)$, 신경 및 감각기계 질환$(85\%)$, 부상 및 중독$(83\%)$, 신생물$(79\%)$, 등에서 필요성 인식 율이 높았다. 4. 가정간호사업 이용에 대한 대상자의 의견을 $47.8\%$가 이용할 의사가 있었고, $49.9\%$는 상황에 따라 결정하겠다고 하였으며, $3.2\%$는 이용하지 않겠다고 응답하였다. 인구학적 변수별로 보았을 때, 연령별로는 노년층, 성별로는 남성이, 교육수준은 낮은 군이, 의료보험을 가진 군이 이용할 의사가 많았으며, 통계적으로 유의한 차이가 있었다. (P<.01, p<.001, p<01, p<.01). 5. 환자들의 가정간호사업 이용 의사는 퇴원시의 상태에 따라서 유의한 차이가 있어서 (P<.02), 상태 가 입원 시와 변화가 없거나 악화된 군이 이용할 의사가 많았다. 진단별로는 내분비계 질환$(63\%)$, 신생물$(57\%)$, 혈액 및 조혈기능 장애$(55\%)$, 부상 및 중독$(55\%)$, 등이 이용할 의사가 많았다. 6. 대상자들이 가정간호사업의 장점으로 생각하는 것은 환자의 심리적 안정$(66\%)$, 시간 절약$(57\%)$, 가족의 편이$(57\%)$, 환자 간호에 대해 배운다$(53\%)$, 질병 과정을 배운다$(51\%)$ 등이었다. 7. 대상자들이 가정간호사업의 단점으로 생각하는 것은 응급시에 대처하기가 어렵다$(49\%)$, 환자가 불안해 할 것이다$(41\%)$ 가정환경이 환장에게 부적합하다$(43\%)$ 등이었다. 8. 가정간호사업에서 수용할 수 있는 간호 업무로$50\%$ 이상의 대상자가 지정한 것은 활력징후측정, 경구 및 비경구 투약, 운동과 휴식지도, 개인 위생관리, 보건교육, 정신 심리 간호 등이었다. 9. 가정간호사업에 대한 지불방법은 $32.9\%$가 제공된 업무에 따라 지불해야 한다는 의견으로 가장 많았다.

• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.655-660
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• 2009

Purpose : To compare birth weight between infants with a single umbilical artery (SUA) and normal infants, investigate the associated anomalies of infants with SUA and isolated SUA (no abnormality of external appearance on birth, except SUA), and determine the prognosis of infants with isolated SUA. Methods : Live-born infants with SUA (n=59) detected by physical examination from among 15,193 live births in seven university hospitals in Korea between January 1, 2004, to August 1, 2007, were reviewed retrospectively, with 236 normal infants serving as the control group. Results : A statistical difference was observed between the groups in birth weight and in vitro fertilization. The incidence of infants with SUA was 0.37%. Congenital malformations were observed in 21 infants with cardiovascular (n=15, 25.4%), gastrointestinal (n=2, 3.4%), genitourinary (n=9, 15.3%), neuromusculoskeletal (n=6, 10.2%), central nervous system (n=1, 1.7%), chromosomal (n=1, 1.7%), and other (n=3, 5.1%) abnormalities. There were 49 (83.1%) infants with isolated SUA in this study population; among them, the associated congenital malformations were cardiovascular (n=6, 12.2%) and genitourinary (n=6, 12.2%) abnormalities. Two infants with cyanotic heart disease were operated and four infants with acyanotic heart disease showed improvements without any treatment. Six infants with genitourinary abnormalities on renal ultrasound had mild hydronephrosis without further consequences. Conclusion : The incidence of structural abnormalities in the cardiovascular and genitourinary systems is high and the genitourinary anomalies associated with isolated SUA have relatively good prognosis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.328-333
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• 1983

Due to fast industrialization and reduced agricultural population, there has been increased farm mechanization to reduce the labor requirement. In rice production, mechanical transplanting has been increasingly popular due to the heavy labor requirement in hand transplanting and development of convenient transplanters. For mechanical transplanting, rice seedlings is grown in boxes with limited soils under super dense population, thus short period of exposure to unfavorable temperature and poor water management would cause severe damage to rice seedlings such as seedling damping off and the similar physiological disorders. Several chemicals were evaluated for their effectiveness to control the disease and disorders, and other effects as plant growth stimulants. 3-hydroxy-5-methylisoxazole-a soil fungicide, Metalozyl-a fungicide which controls mildew, SF 8002-the composite of above two chemicals, and Isoprothiolane-a fungicide which controls rice blast were found to be effective controling seedling damping off and similar physiological disorders, and improvement of physiological characteristics of the seedlings such as the amount of bleeding sap, rooting ability, negative geotrophism, and regrowth after cutting. The results indicated that the chemicals will be very effective raising healthy seedlings even under unfavorable environments by the improvement of physiological activities of seedlings and preventing seedling damping off and the similar physiological disorders.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.160-168
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• 2003

In Korea, a large portion of aerial power-transmission cables is installed in the mountains. In the case of a fire in the mountains, steel wires coated with zinc and aluminum wires of those power cables exposed to the fire or near around will be deteriorated by the blaze and the high temperature. Deterioration proceeds by interactions of a variety of factors like quality, manufacturing process, the condition of installation and exposure environment of a wire, and so on. Generally, the characteristic of a conductor affect by a forest fire can not be analyzed without the effect through simulating a forest fire. However, there are little research accomplishments of that kind of simulation about it, and there's been no analysis of a sample exposed to an actual forest fire. This thesis shows the experimental results that apply to a new wire by an artificial flame-maker because it's difficult to directly analyze the characteristic of deterioration by a forest fire. Those results include the intensity of extension and wrench for a conductor. In addition, there's been an experiment and analysis about the mechanical characteristics of the wire of ACSR 480[$\textrm{mm}^2$] which was removed from Pohang area by a forest fire. Then, the database will be made to predict the state of deteriorated wires by a forest fire using those two data, and data necessary to diagnose the life state of an ACSR wire affected by a forest fire will be given.

• Tuberculosis and Respiratory Diseases
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• v.52 no.1
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• pp.46-53
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• 2002

Background: Pulmonary aspergilloma is relatively common in korea. It arises from the colonization and proliferation of Aspergillus in preexisting lung parenchymal cavities, in particular tuberculosis. The most common symptom in this disorder is hemoptysis, which mayor may not be massive and life threatening. A routine chest radiography and computed tomography (CT) are the most important diagnostic procedures. A surgical resection of the aspergilloma has recently been recommended, because of the relatively low incidence of postoperative complications than in the past. A more concentrated sample of patients with aspergilloma, who either underwent a thoracotomy or tested positive for aspergillus antibodies, were reviewed. Method : The medical records of twenty-two patients with aspergilloma, who had a proven thoracotomy (9 cases), or who tested positive for the diagnostic procedure and/or aspergillus antibodies (13 cases) from January 1995 to December 2000, were reviewed retrospectively. Results : The most common underlying lung disease was a current or old healed tuberculosis, and 3 patients had cultures of mycobacterium other than tuberculosis (MOTT). The mean time until the aspergilloma was detected 5.91 years in the healed tuberculosis cases. The others cases involved a lung abscess, bronchiectasis and without lung disease. The extrapulmonary disease was alcoholism and diabetes. Hemoptysis was most common in 72.7%. A computed tomography (CT) is useful for diagnosis. The right upper lobe, especially the posterior segment, is the most common location. Bronchial artery embolization is ineffective for a long term follow-up. A lobectomy is most common in a thoracotomy, and intra-operative and post-operative complications are rare. During follow-up, the mortality rate, not from the aspergilloma but from respiratory failure, was 13.6%. Conclusion : Aspergilloma is a common cavitary lung disease, It mainly arises from tuberculosis, either current or healed, but extra-pulmonary disease including alcoholism or diabetes are other possible risk factors. Their most common problem in aspergilloma is hemoptysis. Surgery has a low risk of post-operative complications and is recommended in relatively preserved lung function or healthy patients. Medical maneuvers including embolization, and the local insertion of certain materials needs to be studied more closely.