• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.380-385
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• 2001

The paper presents a new multidisciplinary design optimization architecture using optimal sensitivity and coordination of interdisciplinary design variables. Original design problem is decomposed into a number of sub-problems that represent individual engineering analysis. The coupled effects between sub-problems are computed by interdisciplinary design variables. System level coordination is determined by optimal parameter sensitivity calculated by finite difference method. The proposed. MDO strategy is applied to a simplified model of rotorcraft blade design associated with structures and aerodynamic disciplines.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1822-1830
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• 2002

The paper describes the development of a decomposition based multidisciplinary design optimization (MDO) method that coordinates each of disciplinary subspace optimization (DSO). A multidisciplinary design system considered in the present study is decomposed into a number of subspaces based on their own design objective and constraints associated with engineering discipline. The coupled relations among subspaces are identified by interdisciplinary design variables. Each of subsystem level optimization, that is DSO would be performed in parallel, and the system level coordination is determined by the first order optimal sensitivities of subspace objective functions with respect to interdisciplinary design variables. The central of the present work resides on the formulation of system level coordination strategy and its capability in decomposition based MDO. A fluid-structure coupled design problem is explored as a test-bed to support the proposed MDO method.

• Earthquakes and Structures
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• 제21권6호
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• pp.653-667
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• 2021

In this study, cyclic loading tests were conducted on the precast concrete (PC) wide beam (WB)-column joints. Two beam-column joint specimens were fabricated with the arrangement and anchorage details of the reinforcing bars penetrating the beam and column as variables. Through a cyclic loading test, the lateral load-story drift ratio responses, seismic performance characteristics (e.g., ductility, overstrength factor), energy dissipation, strength and stiffness degradations of each specimen were compared and analyzed based on the various indices and the current structural codes (ACI 318-19 and ACI 374.1-05 report). In addition, the shear lag effect was confirmed through the gauge values of the PC beam, and the differences in seismic performance between the specimens were identified on that basis.

• 복식문화연구
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• 제29권6호
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• pp.810-827
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• 2021

Indonesian women have emerged as global consumers, and various studies are needed to expand the global fashion market targeting their needs. In this study, a survey was conducted to determine the fashion design preferences of Indonesian Muslim women according to demographic characteristics and religious variables. In this study, Indonesian women aged from their teens to their 40s were surveyed by questionnaire during June 2020. This yielded 301 survey responses, which were analyzed using χ²-test, t-test, ANOVA, and Duncan's multiple range test using SPSS23. The results of the study are as follows: Analysis of the demographic characteristics of Indonesian Muslim women and the degree of acceptance of fashion trends according to religious variables showed significant differences according to age, monthly income, and the extent to which they wore a hijab. Analysis of the demographic characteristics of the women and the degree of acceptance of the fitted garment according to religious variables showed significant differences depending on their age, whether they were married, their monthly income, religious faithfulness, the extent to which they wore a hijab, and the degree of acceptance of Islamic discipline. After examining the difference in Muslim women's preferred fashion images (according to demographic characteristics and religious variables), significant differences were identified according to their age, income, extent to which they wore a hijab, and the degree of Islamic discipline with regard to clothing.

• 대한기계학회논문집A
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• 제29권3호
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• pp.395-402
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• 2005

Recently Multidisciplinary Design Optimization Based on Independent Subspaces (MDOIS), an MDO (multidisciplinary design optimization) algorithm, has been proposed. In this research, an MDO problem is defined for design of a belt integrated seat considering crashworthiness, and MDOIS is applied to solve the problem. The crash model consists of an airbag, a belt integrated seat (BIS), an energy absorbing steering system, and a safety belt. It is found that the current design problem has two disciplines - structural nonlin- ear analysis and occupant analysis. The interdisciplinary relationship between the disciplines is identified and is addressed in the system analysis step in MDOIS. Interdisciplinary variables are belt load and stiffness of the seat, which are determined in system analysis step. The belt load is passed to the structural analysis subspace and stiffness of the seat back frame to the occupant analysis subspace. Determined design vari- ables in each subspace are passed to the system analysis step. In this way, the design process iterates until the convergence criterion is satisfied. As a result of the design, the weight of the BIS and Head Injury Crite- rion (HIC) of an occupant are reduced with specified constraints satisfied at the same time. Since the system analysis cannot be formulated in an explicit form in the current example, an optimization problem is formu - lated to solve the system analysis. The results from MDOIS are discussed.

• Computers and Concrete
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• 제30권1호
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• pp.75-83
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• 2022

This study introduced a post-tensioned precast concrete system that was developed and designed to improve the performance of joints by post-tensioning. Full-scaled specimens were tested to investigate flexural performances at the negative moment region, where the test variables were the presence of slabs, tendon types, and post-tensioned lengths. A specimen with slabs exhibited significantly higher stiffness and strength values than a specimen without slabs. Thus, it would be reasonable to consider the effects of a slab on the flexural strength for an economical design. A specimen with unbonded mono-tendons had slightly lower initial stiffness and flexural strength values than a specimen with bonded multi-tendons but showed greater flexural strength than the value specified in the design codes. The post-tensioned length was found to have no significant impact on the flexural behavior of the proposed post-tensioned precast concrete system. In addition, a finite element analysis was conducted on the proposed post-tensioned precast concrete system, and the tests and analysis results were compared in detail.

• Child Health Nursing Research
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• 제16권1호
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• pp.73-83
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• 2010

Purpose: This study was designed to analyze recent trends in pediatric oncology research in Korea and suggest future research directions in this area. Methods: Studies (105) selected from http://www.riss4u.net for last 15 yr were used. They were analyzed by publication type, field and design of the study, study participants, main theme, and outcome variables used in intervention studies. Results: 1. Of the 105 studies, 67 were master and doctoral dissertations and 49.5% of studies were conducted in nursing. 2. There were 73 (69.5%) quantitative studies and 20 (19.1%) qualitative research studies and the most frequently used study design was that of a descriptive study. 3. Children with cancer undergoing treatment and their parents, mostly mothers, were the participants most frequently studied. 4. Most themes were psychological/spiritual problems, coping, and family function. 5. Most frequently measured outcome variables were nausea/vomiting, fear/anxiety and adjustment. Conclusion: The results indicate that future research should include more well-designed intervention studies to develop new intervention protocols and to confirm the effect of previous study findings. It is also necessary to use an interdisciplinary approach to deal with physical and psychosocial needs of these children and their families including siblings and fathers of children with cancer.

• Journal of Ship and Ocean Technology
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• 제8권2호
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• pp.41-60
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• 2004

Ship design process requires lots of complicated analyses for determining a large number of design variables. Due to its complexity, the process is divided into several tractable designs or analysis problems. The interdependent relationship requires repetitive works. This paper employs collaborative optimization (CO), one of the multidisciplinary design optimization (MDO) techniques, for treating such complex relationship. CO guarantees disciplinary autonomy while maintaining interdisciplinary compatibility due to its bi-level optimization structure. However, the considerably increased computational time and the slow convergence have been reported as its drawbacks. This paper proposes the use of an approximation model in place of the disciplinary optimization in the system-level optimization. Neural network classification is employed as a classifier to determine whether a design point is feasible or not. Kriging is also combined with the classification to make up for the weakness that the classification cannot estimate the degree of infeasibility. For the purpose of enhancing the accuracy of a predicted optimum and reducing the required number of disciplinary optimizations, an approximation management framework is also employed in the system-level optimization.

• 대한기계학회논문집A
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• 제28권2호
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• pp.109-117
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• 2004

Optimization has been successfully applied to systems with a single discipline. As many disciplines are involved in coupled fashion, MDO (multidisciplinary design optimization) technology has been developed. MDO algorithms are trying to solve the coupled aspects generated from interdisciplinary relationship. In a general MDO algorithms, a large design problem is decomposed into small ones which can be easily solved. Although various methods have been proposed for MDO, the research is still in the early stage. This research proposes a new MDO method which is named as MDOIS (Multidisciplinary Design Optimization Based on Independent Subspaces). Many real engineering problems consist of physically separate components and they can be independently designed. The inter-relationship occurs through coupled physics. MDOIS is developed for such problems. In MDOIS, a large system is decomposed into small subsystems. The coupled aspects are solved via system analysis which solves the coupled physics. The algorithm is mathematically validated by showing that the solution satisfies the Karush-Kuhn-Tucker condition.

• 유통과학연구
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• 제15권7호
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• pp.53-59
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• 2017

Purpose - In the airline industry, an airport plays an important role. There are a lot of employees who work at an airport, and most of the workers experience restraints regarding leisure activities. Thus, there is a need for studying the internal marketing in the airport to better serve the worker. Although there is a lack of well-structured research regarding the restrictions and satisfaction factors experienced by the airport employees for their leisure activities, this research studies how the restrictions and satisfaction factors influence each other in relation to the internal marketing in the airport. The purpose of this research is to provide a detailed, real time research method for studying the restrictions and satisfaction factors in relation to the internal marketing that are experienced by the airport employees regarding their leisure activities. Research design, data, and methodology - This survey was conducted for airport employees working in two shifts. The questionnaire is 152 copies. The analysis method was used as SPSS statistical package 21.0 and Netminer 4.0 program. Social networks were analyzed for leisure satisfaction and leisure restrictions. Results - As a result of analyzing the linkage between variables for leisure satisfaction, most of the variables of leisure satisfaction are satisfied with "psychological factor" and "social factor". However, "educational factor" and "environmental factor" are not satisfied. In order to improve the leisure satisfaction of airport workers in the future, it is necessary to have an environment where leisure activities can be performed and related education. As a result of analyzing the linkage between variables of leisure restrictions, most of the variables in leisure restrictions are "personal factors" and "temporal factors". However, there are few restrictions on "cost-efficient" and "environment-friendly". Conclusions - In the future, in order to reduce the leisure restrictions of airport workers, they need to reduce work stress, psychological time and leisure allowance for leisure activities. However, it is difficult to solve these problems due to realistic problems including the specificity of working at the airport. This research presents an interdisciplinary analysis of how the restrictions and satisfaction factors influence each other in order to further advance the understanding of the constraints and satisfaction that are experienced by the airport employees.