• 한국공간구조학회논문집
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• 제1권1호
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• pp.157-166
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• 2001

In general, the cutting pattern of the membrane structures is determined by dividing the complicated curved 3-D surface into several 2-D plane strip by using flattening technique. In this procedure, however, some discrepancies ore occurred between actual stresses of equilibrated state and designed uniform stresses because the material properties are not considered. These deviations can cause the critical structural problems, wrinkling or overstress, and thus a optimization process should be considered. In this paper, a new analytical method for determining an optimum cutting pattern considering material properties is presented. Here, iterative procedure is introduced to decrease the errors caused in numerical process. The optimization method proposed can diminish the deviations occurred by material properties and numerical errors, simultaneously. As a results, it is shown that the final stress distributions for the HP shell model are sufficiently near to design stress distributions, and it can be concluded that this method can be used to obtain the optimized cutting pattern of membrane structures.

• 한국산학기술학회논문지
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• 제15권9호
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• pp.5610-5620
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• 2014

본 연구는 일부 사무직 행정공무원들의 직무스트레스 수준을 파악하고 사회심리적 요인(A형 행동유형, 통제신념, 자기존중감)과 직무스트레스와의 관련성을 규명하고자 시도하였다. 연구대상은 C도청에 근무하고 있는 공무원 634명(남자 505명, 여자 129명)이었으며, 자료 수집은 2013년 2월 18일부터 3월 10일까지의 기간 동안에 구조화된 무기명 자기기입식 설문지를 이용한 설문조사에 의하였다. 연구결과, 조사대상자의 직무스트레스 수준은 성별, 연령, 학력, 결혼상태, 직급, 근무경력, 공무원생활에 대한 만족도, 흡연상태, 음주상태, 수면시간, A형행동유형, 통제신념 및 자기존중감에 따라서 유의한 차이를 보였다. 사회심리적 요인과 직무스트레스 수준과의 상관관계를 보면, 업무요구도는 내적 통제신념과 유의한 음의 상관관계를 보였으며, 업무의 자율성은 A형행동유형, 내적 통제신념 및 자기존중감과 유의한 음의 상관관계를 보였다. 상사의 지지도는 외적 통제신념과 유의한 음의 상관관계를 보였다. 위계적다중회귀분석 결과 직무스트레스 수준에 영향을 미치는 요인으로는 연령, 주관적인 건강상태, 직위, 잔업시간, 질병으로 인한 결근, 업무에 대한 만족도, 수면시간, 여가시간, 외래진료경험유무, A형행동유형, 통제신념 및 자기존중감이 선정되었으며 이들의 설명력은 32.1%이었다. 위의 모델에서 보면 A형행동유형, 통제신념 및 자기존중감 등의 사회심리적 요인이 추가됨으로 해서 15.0%의 설명력을 증가시켜 직무스트레스에 사회심리적 요인이 큰 영향을 미치고 있음을 알 수 있었다.

• 동의생리병리학회지
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• 제24권3호
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• pp.525-532
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• 2010

Dypepsia is the most common gastrointestinal disease and mainly occurs by stress or food. According to the cause of dyspepsia, the clinical characteristics and the curative process are different in patients. The purpose of this study is to compare acute dyspepsia patients depending on food factor and stress factor. For this study, we analyzed the cause, and the symptoms of 59 acute dyspepsia patients and divided them into two groups: one group is 27 acute dyspepsia patient group caused by stress factor (stress factor group). The other group is 32 acute dyspepsia patient group caused by food factor (food factor group). In addition, we carried out HRV test and compared HRV index between two groups. There was no significant difference in past illness involved in gastrointestinal tract diseases between two groups. There were big differences in the frequency of chest discomfort, thurst, lack of appetite, and exhaustion after meals between two groups. There were many changes of tongue fur in food factor group. But there were many changes of tongue body in stress factor group. The pulse pattern is mostly wiry in stress factor group. But, The pulse pattern is mostly slippery in food factor group. HF, TP were significantly lower than food factor group in stress factor group, it means autonomic nerve system was more suppressd in stress factor group than food factor group. Food factor group improved sooner than stress factor group. This study presented the clinically different characteristics (past medical history, symptoms, tongue diagnosis, pulse pattern, curative process) of acute dyspepsia depending on food factor and stress factor. Thus, it provides the necessity of oriental medical diagnosis and treatment called pattern identification for acute dyspepsia.

• 대한치과보철학회지
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• 제34권1호
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• pp.31-69
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• 1996

The purpose of this investigation was to analyze stress distribution in implant supporting tissue according to different types of attachments such as combination bar attachment, Hader bar attachment, O-Ring attachment and Dal-Ro attachment that are used in mandibular overdenture by using two osseointegrated implants, to study the influence that POM IMC used in bar type attachment has in implant supporting tissue and compare the preceding analyses to find out an effective stress distribution method. Three dimensional photoelastic method was used to obtain the following results. (A) Analysis of stress distribution according to attachment type 1. Under vertical load condition, compressive stress was seen at implant supporting area of working side on all the photoelastic models but in Hader bar attachment tensional stress was seen at distal upper area of implant supporting area. Relatively Hader bar and O-Ring attachment showed even stress distribution pattern. 2. Under vertical load condition, compressive stress at implant apex area and tensional stress at implant lateral supporting area were seen at nonworking side of all models. 3. Under $25^{\circ}$ lateral load condition, general compressive stress was seen at working side implant supporting area in most of the models, especially at distal upper supporting area higher compressive stress concentration was seen in combination bar attachment and tensional stress concentration, in Hader bar attachment. 4. Under $25^{\circ}$ lateral load condition, compressive stress at implant apex area and tensional stress at implant lateral supporting area were seen at nonworking side of all models, except O-Ring model which showed compressive stress only. (B) Influence of POM IMC to stress distribution in bar type attachment 5. Under vertical load condition, better stress distribution pattern was seen at working side of combination bar and Hader bar attachment model using POM IMC. 6. Under vertical load condition, stress value was increased at nonworking side of combination bar attachment model using POM IMC and tendency of increasing compression was seen at nonworking side of Hader bar attachment model using POM IMC. 7. Under $25^{\circ}$ lateral load condition, better stress distribution pattern was seen at working side of combination bar attachment model using POM IMC but tendency of increasing stress was seen on working side of Hader bar attachment model using POM IMC. 8. Under $25^{\circ}$ lateral load condition, stress reduction was seen at nonworking side of combination bar attachment model using POM IMC but tendency of increasing stress was seen at nonworking side of Hader bar attachment model using POM IMC.

• 디지털융복합연구
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• 제14권12호
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• pp.323-333
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• 2016

본 연구는 일부 여대생의 자아존중감, 무망감, 우울, 통제위치 및 A형행동유형과 취업스트레스간의 관련성을 파악하고 취업스트레스에 미치는 융복합적 영향을 분석하였다. 조사대상은 전북지역에서 임의로 선정된 531명의 여대생으로 하였으며, 자료수집은 2016년 3월 28일부터 4월 29일까지 자기기입식 설문지를 통해 이루어졌다. 위계적다중회귀분석 결과, 자아존중감이 낮을수록, 무망감이 높을수록, 우울이 높을수록, 외적통제위치가 높을수록, A형행동 유행이 높을수록 취업스트레스가 높았으며 이들의 설명력은 43.2%이었다. 공분산 구조분석 결과, 자아존중감, 무망감, 우울, 통제위치 및 A형 행동유형과 취업스트레스의 인과관계가 확인되었다. 이상의 연구결과를 볼 때, 여대생의 취업스트레스를 낮추기 위해서는 자아존중감을 높이고 무망감, 우울, 통제위치 및 A형행동유형을 낮추는 노력이 필요하다. 이러한 결과는 여대생의 취업스트레스를 줄이는 프로그램 및 정책 개발에 활용이 기대된다. 향후연구에서는 취업스트레스에 영향을 미치는 추가요인에 대한 분석이 필요하다.

• 동의신경정신과학회지
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• 제32권1호
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• pp.1-11
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• 2021

Objectives: To investigate the prevalence of acute stress disorder (ASD) and post-traumatic stress disorder (PTSD) in patients with traffic injuries. In addition, PTSD patients was classified using 'pattern identification for jing ji and zheng chong'. Methods: Questionnaires such as the primary care PTSD screen for DSM-5(PC-PTSD-5), Korean version of PTSD checklist-5 (PCL-5-K), and the instrument of pattern identification for jing ji and zheng chong were conducted on 195 patients within 3 days to 1 year after traffic accidents. Patients were recruited from six medical institutions. Collected data were used to determine the prevalence of acute stress disorder and post-traumatic stress disorder. Results: On PC-PTSD-5, the prevalence was 39.1% for ASD and 50% for PTSD. On PCL-5-K, the prevalence was 20.4% for ASD and 29.3% for PTSD. Satisfying both PC-PTSD-5 and PCL-5-K, the prevalence was 18.2% for ASD and 25.8% for PTSD. As a result of pattern identification for jing ji and zheng chong, 'weakness of heart and gall bladder type' accounted for the highest proportions in both ASD and PTSD groups. Conclusions: In this study, the prevalence was 39.1% for ASD and 50% for PTSD by PC-PTSD-5. Satisfying both PC-PTSD-5 and PCL-5-K, the prevalence was 18.2% for ASD and 25.8% for PTSD. Further large-scale prospective studies are needed to analyze the prevalence of ASD and PTSD, the rate of progression from ASD to PTSD, and the type of pattern identification.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.401-407
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• 2004

This study is on the constant-current stress corrosion test related to the load stress in welded zone and non-welded zone of high tensile strength steel for natural gas transmission. The surface corrosion pattern of the welded zone of API 5L-X65 specimens for natural gas transmission showed global corrosion and narrow pitting, and the pitting was increased by increasing the load stress. Initially, the average relative electrode potential and the average relative current of the high tensile strength steel for natural gas transmission specimens was decreased suddenly, and the average relative electrode potential was higher and the average relative current was lower in welded zone than base metal. and the average relative electrode potential was decreased by increasing the load stress, and the average relative current was somewhat increased by increasing the load stress. The corrosion rate was less in welded zone than base metal, and the corrosion rate was decreased by increasing the load stress.

• Steel and Composite Structures
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• 제19권1호
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• pp.131-152
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• 2015

Easy detection and evaluation of defect in the tube structure is a continuous problem and remains a significant demand in tube inspection technologies. This study is aimed to automate defect detection using the pattern recognition approach based on the classification of high frequency stress wave signals. The stress wave signals from vibrational impact excitation on several tube conditions were captured to identify the defect in ASTM A179 seamless steel tubes. The variation in stress wave propagation was captured by a high frequency sensor. Stress wave signals from four tubes with artificial defects of different depths and one reference tube were classified using the autoregressive (AR) algorithm. The results were demonstrated using a dendrogram. The preliminary research revealed the natural arrangement of stress wave signals were grouped into two clusters. The stress wave signals from the healthy tube were grouped together in one cluster and the signals from the defective tubes were classified in another cluster. This approach was effective in separating different stress wave signals and allowed quicker and easier defect identification and interpretation in steel tubes.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.259-267
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• 2016

Most manufacturing processes, including welding, create residual stresses. Residual stresses can reduce material strength and cause fractures. For estimating the reliability and aging of a welded structure, residual stresses should be evaluated as precisely as possible. Optical techniques such as holographic interferometry, electronic speckle pattern interferometry (ESPI), Moire interferometry, and shearography are noncontact means of measuring residual stresses. Among optical techniques, ESPI is typically used as a nondestructive measurement technique of in-plane displacement, such as stress and strain, and out-of-plane displacement, such as vibration and bending. In this study, ESPI was used to measure the residual stress on the welded part of butt-welded American Society for Testing and Materials (ASTM) A36 specimens with $CO_2$ welding. Four types of specimens, base metal specimen (BSP), tensile specimen including welded part (TSP), compression specimen including welded part (CSP), and annealed tensile specimen including welded part (ATSP), were tested. BSP was used to obtain the elastic modulus of a base metal. TSP and CSP were used to compare residual stresses under tensile and compressive loading conditions. ATSP was used to confirm the effect of heat treatment. Residual stresses on the welded parts of specimens were obtained from the phase map images obtained by ESPI. The results confirmed that residual stresses of welded parts can be measured by ESPI.

• 한국치위생학회지
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• 제17권1호
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• pp.27-37
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• 2017

Objectives: The purpose of the study is to investigate the correlation between stress and smartphone addiction in some university students. Methods: The subjects were 220 health major students in D area. The study was conducted for 2 weeks, in June, 2016. The questionnaire consisted of general characteristics of the subjects, awareness toward stress, stress-coping pattern, and smartphone addiction. Data was analyzed through SPSS 18.0 program. Results: In the analysis of stress levels according to general characteristics, female group showed higher experience compared to male group (high group 46.10, subgroup 44.38) (p<0.05). Male group and higher stress group showed higher experience in problem solving, social support, and emotional stress coping (p>0.05). Stress and stress coping (r=0.322), stress and smartphone addiction (r=0.299) showed positive correlation. The significant factors of smartphone addiction were average daily using time (${\beta}=0.477$, p<0.001), study stress (${\beta}=0.177$, p<0.05), social stress (${\beta}=0.323$, p<0.01), problem solving (${\beta}=-0.320$, p<0.001), social support (${\beta}=0.064$, p<0.05), and emotional stress coping (${\beta}=0.264$, p<0.001). These factors explained 30.8% of the variance in smartphone addiction. Conclusions: The results from this study indicated that stress had a negative impact on smartphone addictions in subjects. It is necessary to provide smartphone addiction management for stress management.