• Proceedings of the KSME Conference
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• 2001.11b
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• pp.921-927
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• 2001

Steady flow bench test is a practical, powerful and widely used test in most engine manufacturers to give a design concept of a new engine. In order to use steady data as a performance index, it is necessary to build some database, which can correlate the port characteristics with engine data. However, it is very hard to investigate all port and valve shapes with experimental tools. The steady flow scheme is relatively simple and its results are bulk ones such as flow rate and momentum of flow. Therefore a CFD code can be easily applied to the port evaluation. In this study, the steady flow test was simulated through two and three-dimensional analysis on intake port design for comparing with experimental data and confirming the feasibility of applying analytic method. For this purpose, the effect of valve curvature on flow rate was estimated by a CFD code. There results were compared with those of real steady flow tests. As a result, the 2-D analysis described the phenomena qualitatively well, and also the results of 3-D analysis were almost consistent with experimental data.

• Journal of Power System Engineering
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• v.3 no.2
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• pp.57-63
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• 1999

The fabrication of $Al_2O_3/Al$ composites by pressureless infiltration technique was made to investigate the effects of processing variables such as content of Mg, processing temperature and time on the infiltration behavior of molten Al and microstructure. When the pure Al was infiltrated into mixtures of Mg and $Al_2O_3$ powder, processing temperature required to spontaneous infiltration was decreased and critical processing temperature and Mg content were $700^{\circ}C$ and 3wt% respectively. The content of Mg was found the most powerful variable for infiltration of molten Al. The infiltration ratio increased with Mg content and processing temperature, however the $Al_2O_3/Al$ composites which were fabricated by high Mg content and processing temperature resulted in non uniform dispersion of $Al_2O_3$ particles by excessive interfacial reaction. XRD pattern indicated that $MgAl_2O_4$ and AIN was observed at the interface of $Al_2O_3$ particles and in the Al matrix as reaction products.

• Journal of KSNVE
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• v.8 no.5
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• pp.949-956
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• 1998

Complex and large lattice type structures are frequently used in design of bridge, tower, crane and aerospace structures. In general, in order to analyze these structures we have used the finite element method(FEM). This method is the most widely used and powerful method for structural analysis lately. However, it is necessary to use a large amount of computer memory and computational time because the FEM requires many degrees of freedom for solving dynamic problems exactly for these complex and large structures. For analyzing these structures on a personal computer, the authors developed the transfer stiffness coefficient method(TSCM). This method is based on the concept of the transfer of the nodal dynamic stiffness coefficient matrix which is related to force and displacement vector at each node. And we suggested TSCM for free vibration analysis of complex and large lattice type structures in the previous report. In this paper, we formulate forced vibration analysis algorithm for complex and large lattice type structures using extened TSCM. And we confirmed the validity of TSCM through computational results by the FEM and TSCM, and experimental results for lattice type structures with harmonic excitation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.4
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• pp.409-417
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• 2009

Nowadays, the construction sites are growing in city every year, so complaints for construction noise have increased more and more. To analyze this noise scientifically, construction noise prediction program was developed in 1998 and 2005 but it is too difficult to apply program in field because there is few soundproof facilities and it can't understand the coordinate system and so on. The aim of this study is to develop noise prediction program to apply in construction sites. For this, the problems of existing program was analyzed and survey was performed to get requestion of field overseer and upgraded program. To get reliability of program, it was compared with sound measurement value in field. As a result, construction sound prediction program have various soundproof facilities data than existing program. It can also analyze multi receiver point at the same time for several construction machinery. Most of all, it is more powerful to set receiver or source in the axis of X, Y, Z. so program user can make use of it easily. An average of difference is -0.9~1.8 dB.

• Computers and Concrete
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• v.21 no.1
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• pp.47-54
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• 2018

Artificial neural network models can be successfully used to simulate the complex behavior of many problems in civil engineering. As compared to conventional computational methods, this popular modeling technique is powerful when the relationship between system parameters is intrinsically nonlinear, or cannot be explicitly identified, as in the case of concrete behavior. In this investigation, an artificial neural network model was developed to assess the residual compressive strength of self-compacted concrete at elevated temperatures ($20-900^{\circ}C$) and various relative humidity conditions (28-99%). A total of 332 experimental datasets, collected from available literature, were used for model calibration and verification. Data used in model development incorporated concrete ingredients, filler and fiber types, and environmental conditions. Based on the feed-forward back propagation algorithm, systematic analyses were performed to improve the accuracy of prediction and determine the most appropriate network topology. Training, testing, and validation results indicated that residual compressive strength of self-compacted concrete, exposed to high temperatures and relative humidity levels, could be estimated precisely with the suggested model. As illustrated by statistical indices, the reliability between experimental and predicted results was excellent. With new ingredients and different environmental conditions, the proposed model is an efficient approach to estimate the residual compressive strength of self-compacted concrete as a substitute for sophisticated laboratory procedures.

• Women's Health Nursing
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• v.21 no.4
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• pp.308-320
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• 2015

Purpose: The aim of this study was to determine the predictive factors for maternal role development for mothers of premature infants. Methods: A descriptive correlational study was conducted. A total sample of 121 mothers of premature infants following discharge from the neonatal intensive care unit were recruited using two strategies; an internet-based survey and an in-person data collection in a tertiary university hospital in Korea. A self-report questionnaire was used to collect data regarding personal, birth variables, marital intimacy, maternal attachment, maternal identity and maternal role development. Results: A hierarchical multiple regression analysis indicated that parity, maternal attachment, marital intimacy and maternal identity were predictors for maternal role development for mothers of premature infants, accounting for 70% of the variance. Among these variables, maternal attachment is the most powerful predictor for maternal role development. Conclusion: Nursing interventions during hospitalization to post-discharge education that includes parents of premature babies with positive interaction between couples strengthening marital intimacy and promotes maternal attachment that leads to integrate maternal identity should be considered by priority. Community-based family services such as home visits should be focused on maximizing the predictive factors for maternal role development in transition to motherhood that can contribute to maternal health as well as optimal growth and development of premature infants.

• Women's Health Nursing
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• v.13 no.2
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• pp.77-87
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• 2007

Purpose: This study was examined the quality of the sexual life among married women in terms of the factor structure of Sexual Quality of Life(SQOL) and evaluated the predictive value of 11 variables for SQOL. Method: Two hundred and ninety-three married women completed the Korean version SQOL scale with information on age, education, length of marriage, family income, health, sexual knowledge, coital frequency, harmony with family members, levels of affection, and general and sexual communication. Data were analysed with principal components and regression analyses. Result: The SQOL scale had two clearly defined factors, Negative Quality of Sexual Life and Positive Quality of Sexual Life, on which all scale items were significantly loaded, accounting for 54.3% of the total variance. Independent regression analysis showed all variables except education to be significant predictors of SQOL with interpersonal variables (general and sexual communication, affection and harmony with family members) being the most powerful predictors. However when the 11 variables were combined together in stepwise analysis, only 6 variables (general communication, age, affection, coital frequency, sexual knowledge and health) were significant, accounting for 39% of the total variance. Conclusion: The Korean version SQOL scale is a good measure to tackle SQOL in married women. To enhance SQOL, strengthening interpersonal interaction focusing on general/sexual communication, affection and harmony with family members seems to be more important than sexual activities and personal characteristics.

• Korean Journal of Adult Nursing
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• v.16 no.1
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• pp.102-110
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• 2004

Purpose: This study was done to identify the degree that perceived social support effects the self esteem of the elderly. Method: A structured questionnaire was administered to 203 elderly subjects from April 2003 to June 2003. The data were analyzed with an SPSS program for escriptive statistics, Pearson's correlation coefficients, t-test, ANOVA, and stepwise multiple regression. Result: The level of social support was moderate; family support received the highest score among sources of support. In types of support, appraisal support was the highest score and material was the lowest. The level of self esteem was also moderate. The score of social support showed a slightly high positive correlation with self esteem. In general characteristics, several variables were significantly related to self esteem. The most powerful predictor of self esteem was material support by family and the variance explained was 19.6%. A combination of material support by family, informational support by relatives, perceived economic status, perceived health status, and having a subject to depend on accounted for 39.8% of the variance in self esteem of the elderly. Conclusion: To increase the self esteem of the elderly, it is necessary to consolidate material support by family.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.4
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• pp.214-220
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• 2007

Recently, most embedded systems have the multi-functions mixed the hardware with the software. The existing sequence programming methods are not suitable to implement the embedded system with multi-functions. So, it can be overcome the limit of a facility implementation by introducing the operating system in system. Also, due to the requirement about the better convenient and comfortable meeting or lecture environment, the necessity of electronic white-board is getting higher. Specially, the education using multimedia information is much more desirable for various and improved lecture at the high school and the university. But the sequence program which have been managed in existing electronic white-board system has some difficulties to achieve the software-oriented systems which has to accomplish many functions. In this paper, we propose the method to implement a facility of electronic white-board through using the embedded linux with excellent performance. The embedded linux presents the powerful software environment for the implementation of an embedded system and makes the realization of many various functions easy because it follows kernel characteristics of linux. In this paper, we describe the details for the structure of hardware, kernel source and device driver of a developed electronic white-board.

• Lingua Humanitatis
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• v.6
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• pp.295-320
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• 2004

$\ulcorner$Xixiangji[West chamber]$\lrcorner$ is one of the most popular Chinese dramas which was first translated into Korean by Chung-hee Kim in 1811. $\ulcorner$Dongsanggi[East chamber]$\lrcorner$is a Korean drama which was written in Chinese by Ok Lee in 1791. It adopted the form of Chinese traditional drama, $\ulcorner$xixianji$\lrcorner$. 1 think theses are very interesting examples which show how we accepted Chinese dramas through translation or modification and created our own dramas in the past. 1 quoted their names in the title because it is thought that they can represent the direction of the stream of cultural exchange between two countries in the past. The direction has recently changed. Han stream[Korean cultural effect] has become very powerful in whole Asia in last 10 years. Cultural exchange between Korea and China has been very steady and popular over 2000 years before the 20th century We used to have cultural identity by using Chinese character and accept many of the cultural aspects from China. Now, we are trying to reestablish the relationship which has been cut off for about 50years. In this paper I tried to retrospect the results of cultural exchange in the past and argue about the problems we are now facing by examining interchange or acceptance of the Chinese drama including translations and theatrical performances. 1 also tried to suggest the diverse ways of mutual exchange to uplift the cultural level of two countries.