• International conference on construction engineering and project management
• /
• 2009.05a
• /
• pp.409-416
• /
• 2009

This paper presents a tool called Quality-Cost optimization system (QCOS), which integrates Multi-Objective Genetic Algorithm (MOGA) and Quality Function Deployment (QFD), for tradeoff between quality and cost of the unitized metal curtain-wall unit. A construction owner as the external customer pursues to maximize the quality of the curtain-wall unit. However, the contractor as the internal customer pursues to minimize the cost involved in designing, manufacturing and installing the curtain-wall unit. It is crucial for project manager to find the tradeoff point which satisfies the conflicting interests pursued by the both parties. The system would be beneficial to establish a quality plan satisfying the both parties. Survey questionnaires were administered to the construction owner who has an experience of curtain-wall project, the architects who are the independent assessor, and the contractors who were involved in curtain-wall design and installation. The Customer Requirements (CRs) and their importance weights, the relationship between CRs and Technical Attributes (TAs) consisting of a curtain-wall unit, and the cost ratios of each components consisting curtain-wall unit are obtained from the three groups mentioned previously. The data obtained from the surveys were used as the QFD input to compute the Owner Satisfaction (OS) and Contractor Satisfaction (CS). MOGA is applied to optimize resource allocation under limited budget when multi-objectives, OS and CS, are pursued at the same time. The deterministic multi-objective optimization method using MOGA and QFD is extended to stochastic model to better deal with the uncertainties of QFD input and the variability of QFD output. A case study demonstrates the system and verifies the system conformance.

• Journal of Korean Clinical Nursing Research
• /
• v.15 no.1
• /
• pp.67-77
• /
• 2009

Purpose: This study was aimed to investigate the effects of Lebed method exercise (LME) on nurses' depression, anxiety and stress. The LME is a therapeutic exercise and movement program developed by Sherry Lebed Davis and expected to lessen the stress level of nurses and enhance the nursing job's satisfaction and efficiency. This study was utilized a non equivalent control group pre-post test design. Method: The subjects were 36 nurses in total; 18 in experimental group and 18 in control group. The data were collected from March to August, 2008. For the experimental group, 8 hour-long lectures on stress management and LME were given for 12 weeks. For the control group, only lectures on stress management was given. Depression, anxiety, perceived stress, and heart rate variability were measured on the subjects in both groups as pre- and post tests. The data were analyzed by Kolmogrov-Smirov test and P-P plot, t-test and $x^2-test$ using the SPSS program. Results: As proposed in the hypothesis, the subjects in the experimental group experienced less depression (t=2.286, p=.029), less anxiety (t=3.319, p=.002) and less perceived stress(t=2.862, p=.007) than those in the control group. Conclusion: The LME is considered an effective exercise to improve depression, anxiety, and to lessen stress for the nurses. The LME program has potential to be one of the effective stress management interventions for nurses in the future.

• Ocean Systems Engineering
• /
• v.13 no.2
• /
• pp.173-193
• /
• 2023

Reliable prediction of the motion of FOWT (floating offshore wind turbine) and associated mooring line tension is important in both design and operation/monitoring processes. In the present study, a 5MW OC4 semisubmersible wind turbine is numerically modeled, simulated, and analyzed by the open-source numerical tool, OpenFAST and in-house numerical tool, Charm3D-FAST. Another commercial-level program FASTv8-OrcaFlex is also introduced for comparison for selected cases. The three simulation programs solve the same turbine-floater-mooring coupled dynamics in time domain while there exist minor differences in the details of the program. Both the motions and mooring-line tensions are calculated and compared with the DeepCWind 1/50 scale model-testing results. The system identification between the numerical and physical models is checked through the static-offset test and free-decay test. Then the system motions and mooring tensions are systematically compared among the simulated results and measured values. Reasonably good agreements between the simulation and measurement are demonstrated for (i) white-noise random waves, (ii) typical random waves, and (iii) typical random waves with steady wind. Based on the comparison between numerical results and experimental data, the relative importance and role of the differences in the numerical methodologies of those three programs can be observed and interpreted. These comparative-study results may provide a certain confidence level and some insight of potential variability in motion and tension predictions for future FOWT designs and applications.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.28 no.4
• /
• pp.409-415
• /
• 2015

For the design of Concrete-Filled Steel Tube(CFST) columns, the outside diameter D to the steel tube thickness t ratio(D/t ratio) is limited to prevent the local buckling of steel tubes. Each design code proposes the respective model to compute the maximum D/t ratio using the yield strength of steel $f_y$ or $f_y$ and the elastic modulus of steel E. Considering the uncertainty in $f_y$ and E, the reliability index ${beta}$ for the local buckling of a CFST section can be calculated by formulating the limit state function including the maximum D/t models. The resulted ${beta}$ depends on the maximum D/t model used for the reliability analysis. This variability in reliability analysis is due to ambiguity in choosing computational models and it is called as "modelling uncertainty." This uncertainty can be considered as "non-specificity" of an epistemic uncertainty and modelled by constructing possibility distribution functions. In this study, three different computation models for the maximum D/t ratio are used to conduct reliability analyses for the local buckling of a CFST section and the reliability index ${beta}$ will be computed respectively. The "non-specific ${beta}s$" will be modelled by possibility distribution function and a metric, degree of confirmation, is measured from the possibility distribution function. It is shown that the degree of confirmation increases when ${beta}$ decreases. Conclusively, a new set of reliability indices associated with a degree of confirmation is determined and it is allowed to decide reliability index for the local buckling of a CFST section with an acceptable confirmation level.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.7
• /
• pp.337-352
• /
• 2017

Clone-and-own reuse is an approach to creating new software variants by copying and modifying existing software products. A family of legacy software products developed by clone-and-own reuse often requires high maintenance cost and tends to be error-prone due to patch-ups without refactoring and structural degradation. To overcome these problems, many organizations that have used clone-and-own reuse now want to migrate their legacy products to software product line (SPL) for more systematic reuse and management of software asset. However, with most of existing methods, variation points are embedded directly into design and code rather than modeled and managed separately; variation points are not created ("engineered") systematically based on a variability model. This approach causes the following problems: it is difficult to understand the relationships between variation points, thus it is hard to maintain such code and the asset tends to become error-prone as it evolves. Also, when SPL evolves, design/code assets tend to be modified directly in an ad-hoc manner rather than engineered systematically with appropriate refactoring. To address these problems, we propose a feature-oriented method for extracting a SPL asset from a family of legacy applications. With the approach, we identify and model variation points and their relationships in a feature model separate from implementation, and then extract and manage a SPL asset from legacy applications based on the feature model. We have applied the method to a family of legacy Notepad++ products and demonstrated the feasibility of the method.

• Journal of Korean Society of Transportation
• /
• v.34 no.5
• /
• pp.409-420
• /
• 2016

Korea is expected to enter 'Super Aged Society' in 2026. However, as walking is the very basic human right of mobility, securing safe and convenient moving of elderly people comprising the majority of transportation vulnerable is thought to be the most basic welfare, which can be easily neglected. From this perspectives, this study provides the walking characteristics of elderly people to be used in design of pedestrian facilities. The analysis of the measurements using Motion Analysis Systems shows that all walking factors of elderly people is 75% level of the younger group. Elderly group shows slower movement, reduced shoulder movement and increased ankle movement compared to the others. Also, foots are risen less and ground repulsive force is increased. Cluster analysis shows that the group of the elderly shows high variability inside the group, and 2 or 3 clusters can be formed with factors of Walking, Balance and Muscles. These walking characteristics can be used in designing pedestrian road, slope and step height of roadway facilities.

• Journal of the Korean Society of Tobacco Science
• /
• v.21 no.2
• /
• pp.109-118
• /
• 1999

A model predicted describing the effect of cigarette making materials on the level of filter ventilation was developed and evaluated. The developed model was expressed in terms of a linear and quadratic relationship which was validated with experimental measurements for different porosity of plug wrap and tipping paper, unencapsulated pressure drop of filter plug and cigarette column and vent position. Forty-six experimental frequencies were determined as a result of using three levels with five factors Box-Behnken design and analyzed by the multiple regression analysis with backward stepwise in STATISTICA/PC under restricted conditions. The four factors, except filter pressure drop variable, were statistically significant at the level of 0.05 but most of all linear by linear interactions were comparatively lower significant. By the analysis of linear and quadratic regression coefficient, filter ventilation of the cigarette was affected by porosity of plugwrap (5.87, -4.25), porosity of tip paper (5.68, -1.00), vent position (-3.87, 3.08), tobacco column pressure drop (2.56, 0.66), and filter pressure drop (1.50, 0.58) in the decreasing order. It should be emphasized that the major conclusion of this study was not that any particular parameter was linear or quadratic on any limit scale, but that there were highly significant relationships among factors involving linear, quadratic and their interaction and perhaps even linearity between and within factors. While, there is also quite strong evidence that vent position from mouth end and cigarette making materials are reverse relationship on this experimental model. On the basis of the result, it can be concluded that the porosity of the plug wrap and tipping paper has a marked effect on degree of filter ventilation rate. The F-value of plug wrap and tipping paper porosity among five factors were 39.2 and 36.8 respectively with P-value of 0.000 indicating higher significant for both factors. According to the analysis of variance, the model fitted for filter ventilation was significant at 5% confidence level and the coefficient of determination ($R^2$=0.84) was the proportion to variability in the data well fitted for by the model.

• Asian-Australasian Journal of Animal Sciences
• /
• v.22 no.7
• /
• pp.1016-1025
• /
• 2009

Two experiments were conducted to determine energy and nutrient digestibility in four sources of distillers dried grains with solubles (DDGS) produced from corn and fed to growing pigs. The objective was to test the hypothesis that energy and nutrient digestibility in DDGS does not vary if samples are procured from ethanol plants that use similar production technologies and use corn that is grown within a narrow geographical area. The four sources of DDGS that were used were procured from ethanol plants that were less than 10 yr old and located within 250 km of each other. In Exp. 1, five growing barrows (initial BW = 71.4 kg) that were fitted with a T-canula in the distal ileum were allotted to a 5${\times}$5 Latin square design and used to measure apparent (AID) and standardized (SID) ileal digestibility of AA in the four sources of DDGS. Results of this experiment showed that the SID of CP and all AA except Cys and Pro were greater (p<0.05) in two of the DDGS sources than in the other two sources. Exp. 2 was conducted to measure the concentration of DE and ME and the apparent total tract digestibility (ATTD) of energy, N, P, ether extract, NDF, and ADF in corn and in the same four sources of DDGS as used in Exp. 1. Five pigs (initial BW = 29.7 kg) that were placed in metabolism cages and allotted to a 5${\times}$5 Latin square design were used. Results of Exp. 2 showed that the average DE and ME in DDGS were 4,072 and 3,750 kcal/kg DM, respectively, which was less (p<0.01) than the DE and ME in corn (4,181 and 4,103 kcal/kg DM, respectively). The average ATTD for P in DDGS was 56.1%, which was greater (p<0.01) than the ATTD for P in corn (31.9%). The ATTD for ADF in DDGS was also greater (p<0.05) than in corn, but the ATTD for ether extract and NDF were greater (p<0.05) in corn than in DDGS. It is concluded that energy and nutrient digestibility vary among sources of DDGS even when the DDGS is procured from ethanol plants that use corn grown within a narrow geographical region. Thus, factors other than corn growing region are responsible for the variability of energy and nutrient digestibility in DDGS.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1998.11a
• /
• pp.158-162
• /
• 1998

향에 의해 유발되는 감성에 대한 중추신경계 및 자율신경계의 반응의 변화를 측정하기 위해 안정시키는 향과 각성시키는 향을 사용하여 주관적 평가와 동시에 시행하였다. 안정시키는 향으로 1% Lavendar 향을 사용하였고, 각성시키는 향으로 0.8% Jasmin 향을 사용하였으며, 안정상태를 향자극 전후에 측정하여 대조군으로 사용하였다. 중추신경계의 지표로 뇌파측정을 하였고 뇌파의 전극은 international 10-20 system에서 4 채널을 사용하였으며, 자율신경계의 지표로는 심전도, heart rate, 피부저항, 피부온도를 기록하였다. 뇌파의 분석은 Fast Fourier Transform analysis의 power spectra로 하였고, 그 frequency bands는 theta(4-8Hz), alpha(8-l3Hz), beta(14-30Hz)로 하였다 또한 심전도를 이용하여 심전도 상의 연속적인 R-R peak간 시간간격을 시계열 데이터로 재구성한 Heart rate variability 분석도 하였다. HRV 분석을 보다 정확히 할 수 있도록 호흡이 심전도에 미치는 영향을 제거하기 위하여 호흡을 분당 20회로 일정하게 하였다 생체신호 측정과 동시에 실시한 주관적 검사에서 lavendar 향은 친숙하게, jasmin 향은 활기차고 상쾌하고 유쾌하게 평가되었다. 뇌파 분석에서 lavendar 향을 주었을 때 theta의 증가 양상을 보였으며, Jasmin 향을 주었을 때는 모든 채널에서 beta 파의 증가 양상을 보였다. 또한 HRV 분석 결과 부교삼신경의 활동성이 부각되는 HF/LF의 값이 lavendar에서는 대조 자극보다 높게 나타났으며, jasmin에서는 대조자극보다 낮은 값이 나타나는 경향을 보였다. 결론적으로 안정과 각성의 후각 자극으로 인한 감성의 변화를 뇌파와 자율신경계 등의 생체지표로 관찰할 수 있었다.정하는 감성요인의 차이를 알 수 있었으며 또한 essential oil에서는 성별 차이가 없는데 반해 페르몬 향의 경우 성별의 차이를 나타내었다.. 방법을 타액과 혈청내 testosterone 농도 측정에 응용하여 RIA의 결과와 비교하여 본 바 상관관계가 타액에서 r=0.969, 혈청에서 r=0.990으로 두 결과가 잘 일치하였다. 본 실험에서 측정된 한국인 여성의 타액내 testosterone농도는 107.7$\pm$12.0 pmol／l이었고, 남성의 타액내 농도는 274.2$\pm$22.1 pmol／l이었다. 이상의 결과로 보아 본 연구에서 정립된 EIA 방법은 RIA를 대신하여 소규모의 실험실에서도 활용할 수 있을 것으로 사려된다.또한 상실기 이후 배아에서 합성되며, 발생시기에 따라 그 영향이 다르고 팽창과 부화에 관여하는 것으로 사료된다. 더욱이, 조선의 ${\ulcorner}$구성교육${\lrcorner}$이 조선총독부의 관리하에서 실행되었다는 것을, 당시의 사범학교를 중심으로 한 교육조직을 기술한 문헌에 의해 규명시켰다.nd of letter design which represents -natural objects and was popular at the time of Yukjo Dynasty, and there are some documents of that period left both in Japan and Korea. "Hyojedo" in Korea is supposed to have been influenced by the letter design. Asite- is also considered to have been "Japanese Letter Jobcheso." Therefore, the purpose of this study is to loo

• Bulletin of the Society of Naval Architects of Korea
• /
• v.26 no.3
• /
• pp.9-20
• /
• 1989

It is important to enhance the safety of ship structures as much as possible in order to prevent the disastrous collapse of structures. In fact, the strength problem of structures is closely related with the safety problem of structures. Recently, the direct calculation method using a rational approach based on the first principle is implemented into the structural design process instead of adopting empirical approach based on the rules. The structural designer have shown increased concern with the problem of adequacy of conventional design method based on the safety factor since it does not fully take into account some degree of variability of the applied loads on and the strength of ship structures. To deal with the analysis of structures effectively, it is necessary to have three stages being equally treated. The first one is load analysis, second one response analysis, third one safety analysis. For marine structures, most of research effort has been however put into the first and second stages. The third stage is normally done by simple procedures. Hence, the various probabilistic methods are compared in order to establish the reliability analysis techniques for ship structures. As a result, the advanced level 2 method is selected as a most effective and accurate reliability method. The validity of this method is further demonstrated by comparing the results with the conventional method for the problem of the longitudinal strength of hull girder of Ro-Ro ship.