• 한국산학기술학회논문지
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• 제21권4호
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• pp.156-163
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• 2020

본 연구는 구급대원을 대상으로 현 출동벨에 대한 스트레스를 파악하고 출동벨에 대한 요구 및 개선점을 파악하여 현실적으로 적용 가능한 출동벨 변경을 위한 기초자료로 제공하기 위한 조사연구이다. 자료 수집은 2019년 8월 28일부터 9월 21일까지 자발적 의사에 의해 연구에 동의하는 대상자 267명을 대상으로 온라인 설문조사로 수집되었다. 연구도구는 구조화된 설문지를 이용하였다. 연구결과는 SPSS/WIN 23.0을 사용하여 평균과 표준편차, 백분율 및 빈도 분석, 독립표본 t-검정으로 분석하였다. 현 근무지의 구급 출동벨 유형은 복합형이 143명(53.4%)으로 가장 많았고 출동벨에 대한 부정적인 생각이 132명(49.4%)으로 높아 주기적인 교체가 필요하다고 사료된다. 상황별 스트레스로는 취침 중에 출동벨을 들었을 때 4.35±0.94로 가장 높았다. 일평균 구급출동 횟수에 따른 취침 중 스트레스에서는 9회 이상과 9회 미만 출동하는 그룹이 통계학적으로 유의미한 차이를 보였다(p<0.05). 구급대원이 원하는 출동벨의 유형으로는 '부드러운 음악'과 '자연의 소리' 등으로 현 출동벨의 교체를 원하는 비율이 168명(62.9%)으로 절반 이상을 차지하였고, 24개월 이내로 주기적인 출동벨의 교체를 원하는 비율도 163명(91.6%)으로 높기 때문에 출동벨에 대한 개선이 필요할 것으로 사료된다.

• 한국철도학회논문집
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• 제20권5호
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• pp.649-657
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• 2017

본 연구의 목적은 궤도형식별로 사용레일의 피로수명을 평가하는 것이다. 이를 위해 궤도형식별 사용레일에 대한 실내피로시험을 수행하여 파괴확률 50%~0.01% 의 S-N 선도를 도출하고, 실험데이터에 대한 가중치 확률해석기법을 사용하여 피로수명을 산출하였다. 여기서, 레일표면요철 및 열차속도를 고려한 사용레일의 휨응력은 기존 연구결과 도출된 레일휨응력 예측식을 이용하여 구하고, S-N 선도로부터 사용레일의 잔존수명을 평가하였다. 평가결과, 자갈도상의 경우 레일의 피로수명이 현 레일교환기준에 비해 약 2억톤 이상 높았고, 콘크리트도상의 레일 피로수명이 자갈궤도에 비해 약 3억톤 이상 높은 것으로 나타났다. 따라서 누적통과톤수에 의한 레일교환기준을 자갈궤도와 콘크리트궤도로 구분할 필요가 있으며, 레일연마를 통한 레일관리가 이루어진다면 기준값이 아닌 목표값으로 관리할 필요가 있다.

• 한국전자통신학회논문지
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• 제5권6호
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• pp.637-644
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• 2010

본 연구는 양식장의 수질 환경 인자의 특성을 과학적으로 분석 요약하여 데이터에 의미를 부여하고자 하는 의도와 주기적 교체가 필요한 용존산소 센서에 대한 비용 절감 차원에서 용존 산소 예측을 위한 다중 회귀 모형식을 개발하는데 목적을 두었다. 고흥 거금도에 위치한 두 양식장의 2008.11월~2009.1월 동절기 데이터의 상관성 분석에서 수온은 용존산소와 pH에서는 음의 상관성을 나타냈고 pH는 염도와 용존산소에서 양의 상관성을 나타냈다. 2009년 금호수산 양식장의 수질인자에 대한 월별 통계량 값과 계절별 수질인자 간 차이를 표로 제시하였고 용존산소 예측을 위한 다중회귀 모형식을 개발하여 실제 관측치와 추정치와의 결과를 그래프로 제시하였다. 개발 된 다중 회귀식은 수온이 용존산소에 음의 영향을 주고 pH는 용존산소에 양의 영향을 준다. 또한 수온이 pH에 비해 용존산소 예측에 월등하게 큰 영향을 미치는 걸로 나타났다.

• 전기학회논문지
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• 제61권11호
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• pp.1758-1764
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• 2012

A large number of wire rope has been used in various inderstiries as Cranes and Elevators from expanding the scale of the industrial market. But now, the management of wire rope is used as manually operated by rope replacement from over time or after the accident.It is caused to major accidents as well as economic losses and personal injury. Therefore its time to need periodic fault diagnosis of wire rope or supply of real-time monitoring system. Currently, there are several methods has been reported for fault diagnosis method of the wire rope, to find out the feature point from extracting method is becoming more common compared to time wave and model-based system. This method has implemented a deterministic modeling like the observer and neural network through considering the state of the system as a deterministic signal. However, the out-put of real system has probability characteristics, and if it is used as a current method on this system, the performance will be decreased at the real time. And if the random noise is occurred from unstable measure/experiment environment in wire rope system, diagnostic criterion becomes unclear and accuracy of diagnosis becomes blurred. Thus, more sophisticated techniques are required rather than deterministic fault diagnosis algorithm. In this paper, we developed the fault diagnosis of the wire rope using probability density estimation techniques algorithm. At first, The steady-state wire rope fault signal detection is defined as the probability model through probability distribution estimate. Wire rope defects signal is detected by a hall sensor in real-time, it is estimated by proposed probability estimation algorithm. we judge whether wire rope has defection or not using the error value from comparing two probability distribution.

• Asian-Australasian Journal of Animal Sciences
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• 제15권5호
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• pp.665-670
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• 2002

The expediency of replacing cost prohibitive and often inaccessible traditional protein supplements prompted the monitoring of hematological parameters was carried out in female goats at 0, 30, 60 and 90 days post feeding. Rumen environment was (3), respectively fed supplements containing either a leaf meal mixture (LMTM) of Leucaena leucocephala-Morus alba-Tectona grandis (2:1:1) or traditional protein supplements groundnut cake (GNC) or soybean meal (SBM) and wheat straw as basal diet. The periodic monitoring of hematological parameters was carried out in female goats at 0, 30, 60 and 90 days post feeding. Rumen environment was studied in bucks in a $3{\times}3$ switch over design. Rumen liquor was collected at 0, 2, 4, 6 and 8 h post feeding after 4 weeks of feeding. The goats fed on LMTM or GNC had similar dry matter intake (g/kg $W^{0.75}$), which was significantly (p<0.05) higher than SBM. Except for packed cell volume (PCV), none of the blood biochemical constituents (Hemoglobin, serum glucose, total protein, serum albumin (A) and globulin(G), A:G ratio, alkaline phosphatase, transaminases) varied significantly due to replacement of 50% dietary protein by LMTM throughout the experiment. GNC group had significantly higher level of PCV than other treatments. However, the level of serum total protein (p<0.01) tended to increase from 60th day onwards irrespective of dietary treatments. The average rumen pH was significantly higher (p<0.001) on SBM followed by LMTM and GNC, respectively. Total volatile fatty acid (TVFA) production was comparable in goats given LMTM or GNC supplements, the corresponding values were significantly different (p<0.001) when compared with SBM. The ammonical-N, total-N and TCA-precipitable-N (mg/100 ml SRL) did not differ significantly among dietary treatments. It may be concluded that supplementing wheat straw with LMTM based concentrate had no adverse effect on voluntary intake, blood biochemical profile and rumen fermentation pattern of the goats.

• 한국치위생학회지
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• 제16권6호
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• pp.849-861
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• 2016

Objectives: The purpose of the study was to investigate the relationships among snack habits, oral health practice, and oral health status in preschool children. Methods: The subjects were 209 preschool children and their mothers in Jeonbuk from March 24 to May 30, 2014. The study instruments comprised snack habits, oral health practice, and oral health status. Data were analyzed for independent t-test, one way ANOVA and hierarchical multiple regression using SPSS Win 21.0 version. Results: Higher dft index was shown in the older age (p=0.033), lower mother's education (p<0.001), lower mother's daily toothbrushing (p<0.001), check-up after tooth-brushing (p<0.001), tooth-brushing practice before sleeping (p<0.001), tooth-brushing practice after snack (p<0.001), regular dental check-up (p<0.001), fluoride and sealant for prevention caries (p<0.001), limitation of sugar snack intake (p<0.007), periodic replacement toothbrush (p=0.022). The cause of higher dft index included soda (p<0.001), yogurt (p<0.001), snack (p=0.002), bread and cake (p=0.002) and caramel and candy (p<0.001). Fruit (p<0.001), vegetable (p<0.001) and milk (p=0.004) decreased dft index. Factors affecting oral health status were tooth-brushing practice before sleeping, tooth-brushing practice after snack, regular dental check-up, fluoride and sealant for prevention caries, and intake of soda, yogurt, caramel, candy, and fruit. The explanation power of the final model was 67.6%. Conclusions: It is necessary to develop the oral health education program for the preschool children and mothers to enhance the best oral health condition.

• 대한족부족관절학회지
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• 제23권3호
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• pp.91-99
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• 2019

Purpose: This retrospective study reports the intermediate-term clinical outcomes including the practical function in daily and sports activities after total ankle arthroplasty for end-stage rheumatoid arthritis, as well as the effects of modification of perioperative anti-rheumatic medications. Materials and Methods: Twelve patients were followed for a minimum of 2 years after total ankle replacement for end-stage rheumatoid arthritis. Perioperative anti-rheumatic medications in all patients were modified based on a specific guideline. Clinical evaluations consisted of American Orthopaedic Foot and Ankle Society (AOFAS) scores, Foot and Ankle Outcome Score (FAOS), and Foot and Ankle Ability Measure (FAAM) scores. Periodic radiographic evaluation was conducted to detect changes in ankle alignment and postoperative complications. Results: Mean AOFAS, FAOS, and FAAM scores improved significantly from 37.5 to 81.2, 39.1 to 72.4, and 33.8 to 64.0 points at final follow-up, respectively (p<0.001). Functional outcomes in daily and sports activities at final follow-up were found to be 76.5 and 55.8 points for the FAOS and 70.5 and 57.5 points for the FAAM, respectively. As early postoperative complications, there was one case of local wound necrosis, one case of medial malleolar fracture, and one case of deep peroneal nerve injury. Radiological evaluation revealed two cases of asymptomatic heterotopic ossification and one case of progressive arthritis in the talonavicular joint. Reoperation was performed in only one patient (8.3%) with a medial soft tissue impingement at a mean of 35.6 months follow-up. Conclusion: Total ankle arthroplasty appears to be an effective surgical option for end-stage rheumatoid arthritis. Practical functions in daily and sports activities were significantly improved at intermediate-term follow-up. Modification of perioperative anti-rheumatic medications can be one of the solutions to reduce the postoperative complication rate.

• 수산해양기술연구
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• 제49권2호
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• pp.116-125
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• 2013

Jigging and angling fishery is prevalent in the East Sea of Korea and this fishery needs many lamps to attract the fish. And the fishing boat uses 24~47 ballasts by the vessel's tonnage to turn on the fishing lamp. A 3.5kW magnetic-type ballast being currently used at many fishing boats can drive two 1.5kW metal-halide lamps. Meanwhile, this ballast has large weight (25kg) and volume. Therefore it is one of reason for the over-consumption of energy and the fire, resulted from overheat and electrical short, occurs occasionally because the ballast is installed at narrow and hot engine room. In addition, most of magnetic ballast has several problems such as periodic condenser replacement, low energy efficiency and making lamp short life, etc. So it is necessary to improve or develop newly the electronic ballast, which has to be smaller, lighter and more efficient. An electronic ballast was designed for the fishing boat by considering duration and electromagnetic interference in the study. Its weight and volume are respectably 40% and 66% compared to current ballast on the basis of PCB. The metal-halide lamp's spectrum of the designed ballast was nearly same to that of the current ballast in the test of lighting. In particular, the light stability was improved and there isn't any radio interference. As mentioned above, it is expected that the developed electronic ballast can replace current magnetic ballast because of many advantages related to energy-saving.

• 한국압력기기공학회 논문집
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• 제6권2호
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• pp.28-33
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• 2010

As a part of license renewal for the continued operation of Wolsong unit 1, the periodic safety review report was submitted near the end of design lifetime, 2012, and now is under reviewing. Major components of primary system such as pressure tubes, feeder pipes and so on are being replaced and many components of secondary system are also being repaired. So the license renewal of Wolsong unit 1 is expected to be acquired without significant issues. But on the other hand, steam generators of Wolsong unit 1 had the good performance and therefore the replacement and repair for the steam generator are not needed. Recently it is reported that some cracks were detected in a few of european steam generator with Alloy 800 tubes and the cause of cracks was the outer diameter stress corrosion cracking(ODSCC) due to the concentration of chemical impurities on the outer surface of tube. Accordingly the overall review on this issue was performed. The long-term operation is likely to results to form the concentration mechanism for the tube corrosion as the sludge build-up in the secondary side of steam generator and the crack in the crevice between tube and tube-sheet and expansion transitions is apt to be occurred. In this paper, the history of steam generator inspection and operation of Wolsong unit 1 are reviewed and the reliability of steam generator tube is evaluated and the steam generator aging management program for Wolsong unit 1 is introduced.

• 산업경영시스템학회지
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• 제43권3호
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• pp.95-100
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• 2020

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. The representative type of the degeneration is wear of tool or machine. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore a periodic preventive resetting the process is necessary. The total cost consists of three items: adjustment cost (or replacement cost), non-conforming cost due to product out of upper or lower limit specification, and quality loss cost due to difference from the process target value and the product characteristic value among the conforming products. In this case, the problem of determining the adjustment period or wear limit that minimizes the total cost is called the 'process mean shift' problem. It is assumed that both specifications are set and the wear level can be observed directly. In this study, we propose a new model integrating the quality loss cost, process variance, and production volume, which has been conducted in different fields in previous studies. In particular, for the change in production volume according to the increasing in wear level, we propose a generalized production quantity function g(w). This function can be applied to most processes and we fitted the g(w) to the model. The objective equation of this model is the total cost per unit wear, and the determining variables are the wear limit and initial process setting position that minimize the objective equation.