• Smart Structures and Systems
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• 제14권4호
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• pp.679-697
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• 2014

The strain data acquired from structural health monitoring (SHM) systems play an important role in the state monitoring and damage identification of bridges. Due to the environmental complexity of civil structures, a better understanding of the actual strain data will help filling the gap between theoretical/laboratorial results and practical application. In the study, the multi-scale features of strain response are first revealed after abundant investigations on the actual data from two typical long-span bridges. Results show that, strain types at the three typical temporal scales of $10^5$, $10^2$ and $10^0$ sec are caused by temperature change, trains and heavy trucks, and have their respective cut-off frequency in the order of $10^{-2}$, $10^{-1}$ and $10^0$ Hz. Multi-resolution analysis and wavelet shrinkage are applied for separating and extracting these strain types. During the above process, two methods for determining thresholds are introduced. The excellent ability of wavelet transform on simultaneously time-frequency analysis leads to an effective information extraction. After extraction, the strain data will be compressed at an attractive ratio. This research may contribute to a further understanding of actual strain data of long-span bridges; also, the proposed extracting methodology is applicable on actual SHM systems.

• Molecules and Cells
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• 제20권3호
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• pp.392-400
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• 2005

The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The $Ser^{83}$ to Thr substitution in Methylovorus sp. strain SS1, and the $Ser^{83}$ to Leu and $Asp^{87}$ to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.409-412
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• 2004

Microstructures and mechanical properties of microalloyed cold forging steel and cold forged prototype automobile part are characterized. The work hardening according to the increase of plastic strain plays a major role in increasing the tensile strength of microalloyed cold forging steel during cold forming. On the other hand, inhomogeneous distribution of plastic strain causes variations in microstructure and mechanical properties. The relation between inhomogeneous distribution of plastic strain and variations in microstructure and mechanical properties is discussed. The variation of mechanical property in cold forged automobile part is analyzed using quantitative evaluation of plastic strain from finite element method.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.73-78
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• 2003

The residual stresses and. distortions of structures by welding exert negative effect on the safety of railroad structures. This investigation performs a thermal elasto-plastic analysis using finite element techniques to evaluate residual stresses in butted-welded joint. Considering this initial residual stresses, local stress and strain at the critical location (weld toe) during the loading were analyzed by elastic plastic finite element analysis. Fatigue crack initiation life and fatigue crack propagation life of butt-welded specimen were predicted by local strain approach and Neuber's role and Paris law. It is demonstrated that fatigue life estimates by local strain approach closely approximate the experimental results.

• 센서학회지
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• 제30권6호
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• pp.420-428
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• 2021

In this study, linearized sweeping of a wavelength sweeping laser was realized. This technique was used to measure the strain on a fiber Bragg grating(FBG) sensor. For linear sweeping, PID control over the wavelength difference between linear and nonlinear sweeping was employed. The performance test showed that linear sweeping with a 46 nm range and a 1 kHz frequency held up well with a 99.5 % decrement in nonlinearity after the 120th feedback. When attached to a strain gage, the FBG sensor registered strain that matched the data sheet within a difference of 4.5[με]. Altogether, linear sweeping can play a leading role in monitoring a safety of large SOC structures as well as in other wavelength sweeping laser related fields.

• 한국직업건강간호학회지
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• 제20권1호
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• pp.55-64
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• 2011

Purpose: This study was to investigate the relationship between the level of emotional labor and occupational job stress of hospital nursing staff. Methods: The survey was conducted from Mar. to Oct. 2009 to collect data from clinical nurses (N=496). Results: The study showed that nurses without religion and those working in big-sized hospitals had higher scores in emotional labor, and those of 26~30 years old felt the highest stress in the occupational role. The same applied to the married, more work experienced, atheist and those working in big-sized hospitals. Unmarried, under educated nurses with less work experience working in the big-sized hospitals showed higher scores in personal strain. The scores of the personal resources depended on religion, work experience, marital status and position of their jobs. Emotional labor was positively correlated with an occupational role and personal strain, respectively, but the emotional labor, occupational role and personal strain were negatively correlated with personal resources respectively. Conclusion: Intervention program is required to reduce overload of nurse's role and to relieve physical and psychological strains of the under-30-age-group. Also, social support and rational/cognitive coping must be reinforced.

• Journal of Applied Biological Chemistry
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• 제56권3호
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• pp.147-156
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• 2013

The objectives of this study were to investigate the effect of Lactobacillus paracasei subsp. tolerans JG22 isolated from pepper leaf jangajji on the mutagenic activity of N-methyl, N'-nitro, N-nitrosoguanidine (MNNG) and 2-nitrofluene (2-NF) and to evaluate the effect of physico-chemical pretreatment on the antimutagenic activity of the strain. The viable cells of JG22 strain displayed a significantly high (p <0.05) antimutagenic activity against both mutagens tested. The antimutagenic effect of JG22 strain seems to be positively correlated with the amounts of the cells in the incubation time. This strain produced the antimutagenic activity of the maximum levels after preincubation for 30 min. The binding of this strain against the mutagenic compounds might be mainly present in the cell wall fraction rather than the cytosol fraction. Pretreatment with proteolytic enzymes and simulated gastric and intestinal juices and at different pH values had no significant effect on two mutagens removal by the viable cells. However, the binding activity of the mutagen by the strain seems to be affected by heating, enzymes including $\alpha$-amylase and lysozyme, divalent ions, and sodium metaperiodate. Thus, carbohydrates consisting of the cell walls may be important elements responsible for the binding of MNNG and 2-NF by this strain. In conclusion, the binding of the mutagens to cells of JG 22 strain may play a vital role in suppressing the process of mutagenesis induced by mutagens.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.1078-1080
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• 2002

The pressure variation of interstitial fluid is one of the most important factors in bone physiology. In order to understand the role of interstitial fluid and the biomechanical interactions between fluid and solid constituents within bone, poroelastic theory was applied. The purpose of this study is to describe the behavior of calf vertebral trabecular bone composed of the porous solid trabeculae and the viscous bone marrow by using a commercial finite element analysis program based on the poroelasticity. In this study, the model was numerically tested for 5 different strain rates, i. e., 0.001, 0.01, 0.1, 1.0, and 10 per second. The material properties of the calf vertebral trabecular bone were utilized from the previous experimental study. Two asymptotic poroelastic response, the drained and undrained deformation, were predicted. From the predicted results for the simulated five strain rate, it was found that the pore pressure generation has a linearly increasing behavior when the strain rate is the highest at 10 per second, other wise it showed a nonlinear the strain rate Increased. Based on the results of the present study, it was suggested that the calf vertebral trabecular bone could be modeled as a porous material and its strain rate dependent material behavior could be predicted.

• 한국가족복지학
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• 제54호
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• pp.7-39
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• 2016

본 연구는 취업모의 양육태도에 영향을 미치는 환경적 요인인 직장과 가정 사이의 역할갈등의 방향적(일${\rightarrow}$가정 역할갈등, 가정${\rightarrow}$일 역할갈등)측면과 유형적측면(시간, 긴장, 행동갈등)을 살펴보고, 취업모의 직장-가정 역할갈등(WFC)과 양육태도의 관계를 분석함으로써 정책적 실천적 함의를 제공하는 데 목적이 있다. 이를 위해 부산 울산 지역의 미취학 자녀를 둔 취업모 267명에 대한 설문조사 자료를 토대로 다중회귀분석을 실시하였다. 주요결과는 다음과 같다. 첫째, 취업모의 직장-가정 역할갈등(WFC)의 방향적 측면과 양육태도를 검증해본 결과, 취업모의 일${\rightarrow}$가정 역할갈등(WIF) 총합이 높을수록 애정적 양육태도에는 부적인 영향을, 거부적 양육태도와 통제적 양육태도에는 정적인 영향을 미치는 것으로 나타났다. 반면, 취업모의 가정${\rightarrow}$일 역할갈등(FIW) 총합이 높을수록 자율적 양육태도에는 부적인 영향을 미치는 것으로 나타났다. 둘째, 취업모의 직장-가정 역할갈등(WFC)의 유형적 측면(시간, 긴장, 행동갈등)과 양육태도를 검증해본 결과, 행동갈등과 시간갈등은 양육태도에 영향을 미치지 못하는 반면 긴장갈등은 양육태도에 영향을 미치는 것으로 나타났다. 취업모의 일${\rightarrow}$가정 긴장갈등이 높을수록 애정적 양육태도에 부적인 영향을, 거부적 양육태도와 통제적 양육태도에는 정적인 영향을 미치는 것으로 나타났다. 또한, 취업모의 가정${\rightarrow}$일 긴장갈등이 높을수록 애정적 양육태도와 자율적 양육태도에 부적인 영향을 미치는 것으로 나타났다. 이러한 결과를 바탕으로 본 연구의 함의와 제언이 제시되었다.

• 한국콘텐츠학회논문지
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• 제20권8호
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• pp.251-261
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• 2020

본 연구에서는 OECD 국가들 간 출산율의 차이를 설명하기 위해 새로운 관점을 제시하고자 한다. 출산율과 관련된 기존 연구들은 대체로 저출산에 대한 국가의 정책적 대응에 초점을 맞추고 있다. 본 연구에서는 직무긴장이라는 요인, 일-가정 갈등을 중심으로 직무긴장과 연관된 수 있는 삶의 만족도, 그리고 가정 내에서 가사노동의 균등한 분배와 출산율 간의 관계에 대해 살펴보았다. OECD에서 제시한 자료를 바탕으로 퍼지셋 질적비교분석을 시행하여 다음과 같은 결과를 확인할 수 있었다. 첫째, 낮은 수준의 직무긴장, 높은 수준의 삶의 만족도, 가사노동의 균등한 분배 및 높은 수준의 GDP를 특징으로 하는 국가들이 대체로 높은 수준의 출산율을 보인다. 둘째, 직무긴장과 삶의 만족도, 그리고 가사노동의 측면에서 좋은 수치를 보이는 경우 GDP가 높은 수준의 출산율과 반드시 연결되는 것은 아니다. 이와 같은 결과를 바탕으로 본 연구에서는, 한국의 출산율 제고를 위해서 일-가정 양립 및 가사노동의 균등한 분배를 가능하게 하는 노동환경 및 조직문화가 필요하고 이를 통해 삶의 만족도를 증진시키는 과정이 필요하다는 점을 제안하였다.