• Journal of the Korea Furniture Society
• /
• v.25 no.4
• /
• pp.331-337
• /
• 2014

The purpose of this paper is to evaluate the moment resistance of glulam post-to-base connections by applying quasi-static cyclic loads. The connectors consisted of inserted plates and drifted pins according to the load direction. The connection types employed in this study were total three including two unidirectional types (H, V) and the multi-directional type (M). The moment resistance of 8 mm-plate M-type is compared to 6 mm plate. Total four types of Post-to-base connection are prepared and tested under pseudo-static reversed cyclic loading. Test results showed that the yield moment of multi-directional connection is about 2 times higher than that uni-directional connections. The ductility ratio of multi-directional connection determined by EEEP was higher that that of uni-directional connection. It was becoming higher as the thickness of plate is increased. The Finite Element Analysis was conducted to estimate the stress distribution behavior of tested connections. Results showed the failure of multi-directional type were caused by the split of pined hole and the shear failure of lifted part of post.

• International Journal of Vascular Biomedical Engineering
• /
• v.3 no.2
• /
• pp.17-24
• /
• 2005

The main purpose of our study is to propose a new methodology to develop the multi-parametric measure including linear and nonlinear measures of heart rate variability diagnosing cardiovascular disease. We recorded electrocardiogram for three recumbent postures; the supine, left lateral, and right lateral postures. Twenty control subjects (age: $56.70{\pm}9.23$ years), 51 patients with angina pectoris (age: $59.98{\pm}8.41$ years) and 13 patients with acute coronary syndrome (age: $59.08{\pm}9.86$ years) participated in this study. To develop the multi-parametric measure of HRV, we used the multiple discriminant analysis method among statistical techniques. As a result, the multiple discriminant analysis gave 75.0% of goodness of fit. When the linear and nonlinear measures of HRV are individually used as a clinical tool to diagnose cardiac autonomic function, there is quite a possibility that the wrong results will be obtained due to each measure has different characteristics. Although our study is a preliminary one, we suggest that the multi-parametric measure, which takes into consideration the whole possible linear and nonlinear measures of HRV, may be helpful to diagnose the cardiovascular disease as a diagnostic supplementary tool.

• Journal of the Korean Home Economics Association
• /
• v.47 no.9
• /
• pp.27-36
• /
• 2009

The purpose of this study to gather information on demographic statistics, children’s attachment to their mothers, and daily stress variants in order to assess their effects on child’s self-concept and depression within multi-ethnic familiy settings. A questionnaire survey was used to targeted 3rd, 4th, 5th and 6th graders in elementary schools in Jeonnam. A total of 158 children were surveyed. SPSS for Windows 12.0 was used to carry out descriptive, and comparative statistical analysis such as Cronbach's $\alpha$, correlations analysis, and a hierarchical regression analysis. Result showed that the most significant variant affecting self-concept among children from multi-ethnic families was attachment to their mothers. Other related individual variants were in order of importance, communication skills, feelings of alienation, and mothers’ nationalities. The variant most responsible for having an affect on depression among children from multi-entnic families was the attachment to their mothers. Other related individual variants were in order of importance, feelings of alienation, stress from peer relationships, mothers’ nationalities, and stress from economic and physical environments.

• Journal of Korean Society for Quality Management
• /
• v.43 no.1
• /
• pp.31-42
• /
• 2015

Purpose: System consists of a lot of units with coherent function. In design phase, various units could be considered with the same function. In this study, we consider the alternative units with the same function and redundancy allocation to maximize system reliability in multi level system. Methods: The redundancy allocation problem with the alternative units in multi level system is formulated. Memetic algorithm(MA) is proposed to optimize the redundancy allocation problem. In addition, the performance of the proposed algorithm is explained by a numerical experiment. Results: MA showed better results than genetic algorithm(GA) and the convergence of the solutions in MA was also faster than GA. In addition, we could know from experiment that system reliability is increased and the chosen unit for redundancy allocation is changed if cost limit is increased. Conclusion: The chose unit for redundancy allocation is changed as resource constraints. It means we need to consider the alternative units in system design. In the future, we need to consider various problem related to redundancy allocation in multi level system and develop the better method to enhance search performance.

• Journal of Korean Society for Quality Management
• /
• v.47 no.4
• /
• pp.701-711
• /
• 2019

Purpose: The problem of optimizing redundancy allocation in multi-level systems is considered when each item in a multi-level system has alternative items with the same function. The number of redundancy of multi-level system is allocated to maximize the reliability of the system under path set and cost limitation constraints. Methods: Based on cost limitation and path set constraints, a mathematical model is established to maximize system reliability. Particle swarm optimization is employed for redundant allocation and verified by numerical experiments. Results: Comparing the particle swarm optimization method and the memetic algorithm for the 3 and 4 level systems, the particle swarm optimization method showed better performance for solution quality and search time. Particularly, the particle swarm optimization showed much less than the memetic algorithm for variation of results. Conclusion: The proposed particle swarm optimization considerably shortens the time to search for a feasible solution in MRAP with path set constraints. PS optimization is expected to reduce search time and propose the better solution for various problems related to MRAP.

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.321-325
• /
• 2007

Recently, demands on thin multi-layer printed circuit boards(PCB) have been rapidly increased with broad spread of personal portable digital appliances such as multi-media. In case of mobile phone, however, the fact that PCBs have low flexural strength might cause defects. The purpose of this study is to improve the flexural strength by substituting the well-known GFRP(glass fiber reinforced plastic) for CFRP(carbon fiber reinforced plastic). Firstly, finite element simulation was carried out using ABAQUS to find out a unique CFRP layer that has a role to sustain the applied forces mainly in PCB. Secondly, three point bending tests were conducted with the newly designed CFRP PCB model to verify the improvement of the flexural strength. Consequently, it is shown that PCB layered with the CFRP on both outer sides of the board can be used to improve the flexural strength effectively.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.38 no.1
• /
• pp.139-152
• /
• 2013

The purpose of this study is to claim the validity of tuning the architecture of neural network models for multi-class classification. A neural network model for multi-class classification is basically constructed by building a series of neural network models for binary classification. Building a neural network model, we are required to set the values of parameters such as number of hidden nodes and weight decay parameter in advance, which draws special attention as the performance of the model can be quite different by the values of the parameters. For better performance of the model, it is absolutely necessary to have a prior process of tuning the parameters every time the neural network model is built. Nonetheless, previous studies have not mentioned the necessity of the tuning process or proved its validity. In this study, we claim that we should tune the parameters every time we build the neural network model for multi-class classification. Through empirical analysis using wine data, we show that the performance of the model with the tuned parameters is superior to those of untuned models.

• Structural Engineering and Mechanics
• /
• v.53 no.5
• /
• pp.897-919
• /
• 2015

In this study, the effects of ground shocks due to explosive loads on the dynamic response of historical masonry bridges are investigated by using the multi-point shock response spectrum method. With this purpose, different charge weights and distances from the charge center are considered for the analyses of a masonry bridge and depending on these parameters frequency-varying shock spectra are determined and applied to each support of the two-span masonry bridge. The net blast induced ground motion consists of air-induced and direct-induced ground motions. Acceleration time histories of blast induced ground motions are obtained depending on a deterministic shape function and a stationary process. Shock response spectrums determined from the ground shock time histories are simulated using BlastGM software. The results obtained from uniform and multi-point response spectrum analyses cases show that significant differences take place between the uniform and multi-point blast-induced ground motions.

• The Journal of Korean Society for School & Community Health Education
• /
• v.13 no.1
• /
• pp.33-43
• /
• 2012

Objectives: The study has a purpose of contributing to understanding children of multi-cultural families and healthy development of children by examining influences of parental attachment perceived by the children on their anger trait and anger expressions. Methods: The data were collected from 113 students in grade 4~6, and analyzed using descriptive statistics, t-test, pearson correlation coefficient by the SPSS/PC 18.0 program. Results: The result showed the stable attachment with parents significantly influences children's anger and expression(anger out/control). And mother's attachment was significantly stronger than father's attachment, especially mutual trust and communication. Father's attachment had significantly negative influences state-trait anger and anger out/in, and mother's attachment had significantly negative influences state-trait anger and anger out. Actually father's attachment had stronger influences children's anger and anger expression. Conclusions: There was relationship between father's attachment and anger trait/ expression by children of multi-cultural families. For the effective management of multi-cultural children's anger, programs focusing on improving father-child relationships need to be established.

• Journal of the Korean housing association
• /
• v.22 no.1
• /
• pp.43-55
• /
• 2011

The purpose this study is to develop indicators that measure the healthy housing condition of multi-family housing. The major findings are as follow: first, healthy housing was defined by physical, mental, social, and management aspects and proposed the conceptual model of hierarchy structure of evaluation of healthy housing by literature reviews. Second, evaluating items were selected based on literature reviews of existing indicators and preceding studies about both domestic and overseas multi-family housing. The evaluating indicators were identified as a total of 87 evaluating items which were composed of four dimensions and 16 attributes on the basis of the conceptual model. They cover comprehensive scope of the multi-family housing such as unit, building, complex, and site. Third, as the measurement, the 5-point ordinal scale measure was suggested. The evaluating measurement including measure standards, measure methods, and measure contents were developed by each evaluating items. Lastly, the weighting of evaluating indicators was developed by AHP method conducted by survey of an expert group. Items were identified as high contributors or low contributors. The weighting of these items could suggest several evaluations according to the situation. The level of healthy housing condition may be evaluated by both total evaluation and a specific field of evaluation.