• Korean Journal of Human Ecology
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• v.15 no.2
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• pp.209-225
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• 2006

The purpose of this study is to research the actual condition of environment and management of outdoor play at child care centers in Seoul, and to present a planning guideline for outdoor play environment. For this purpose, data were collected by a structured questionnaire and subjects were 164 directors of child care centers located in Seoul. The contents of the questionnaire were composed of general facts about the respondent and facility, environmental condition, managerial condition, and director's understanding about outdoor play. The data were then analyzed using the frequency, percentage, mean and crosstab. The major results have shown the following: 1) Most child care centers in Seoul had some space for outdoor play. 62% of them used front yard and 11 % a rooftop. 2) The space usually included fixed play instruments such as slide and complex unit structures, sand play area, and open area. It also had many natural elements as shrubs and earth. 3) 78% of the centers had a schedule for outdoor play. The schedule operates flexibly according to each center's own day schedule. Generally, a time for outdoor play was 21 to 30 minutes. 4) The directors of child care centers thought highly of outdoor play for it contributes to the balanced development of children. They answered that equipments and spaces, program devices, and teacher's understanding are some of the important factors for active outdoor play. 5) Most of them wanted wood-working area (construction activity area), water play area, and cages.

• Knowledge Management Research
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• v.13 no.2
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• pp.19-35
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• 2012

This study empirically investigates the differences of dominant management problems (hereafter, DMPs) among transplants in different degree of localization, based on the exploratory case study on the nine transplants of Hyundai/Kia suppliers in US using AHP(Analytic Hierarchy Process) technique. On the results of the literature review, this study divides the DMPs of transplants into three main categories such as building human infrastructure, stabilizing manufacturing processes, and building learning network. Each categories is also divided into four subcategories. The degree of localization includes two variables such as the localization stage and the employee size of transplant. Main findings are as follows. First, 'Communication among Korean and local employees' is important DMP in all transplants examined. Second, 'Local adaptation of Korean manufacturing technology' and 'Education on the Korean culture and management practices' are more important DMPs for less-localized transplants than more-localized ones. On the contrary, 'Motivating local employees' is more important DMP for more-localized transplants than less-localized ones. Third, 'Education on the technology and quality' is more important DMP for transplants in post-production stage than in stabilization stage. On the contrary, 'Staffing local employees' is more important DMP for transplants in stabilization stage than in post-production stage. Fourth, 'Acquiring test and measurement equipments' is more important DMP for small-sized transplants than large-sized ones. On the contrary, 'adopting new technology' and 'Building local suppliers network' are more important DMPs for large-sized transplants than small-sized ones.

• Journal of Advanced Navigation Technology
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• v.21 no.3
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• pp.306-311
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• 2017

In the future ubiquitous network, information will collect data from various sensors in the field. Since the sensor nodes are equipped with small, often irreplaceable, batteries with limited power capacity, it is essential that the network be energy-efficient in order to maximize its lifetime. In this paper, we propose an effective network routing method that can operate with low power as well as the transmission of data and information obtained from sensor networks, and identified the number of sensors with the best connectivity to help with the proper placement of the sensor. These purposes of this research are the development of the sensor middle-ware to integrate the maritime information and the proposal of the routing algorithm for gathering the maritime information of various sensors. In addition, for more secure ship navigation, we proposed a method to construct a sensor network using various electronic equipments that are difficult to access in a ship, and then construct a communication system using NMEA(the national marine electronics association), a ship communication standard, in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1515-1521
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• 2013

AIS is a core service in the maritime safety domain. AIS Message type #6 and #8(for binary date) can be used for carrying any kind of MSI(Maritime Safety Information). The MSC(Maritime Safety Committee) approved SN/Circ. 289 on Guidance on the use of AIS Application-Specific Messages in 2010. The MSI that carried by AIS-ASM can support to reduce the maritime accidents. Since a new AIS-ASM service places an additional load on the VDL(VHF Data Link), there should be a deployment process for new AIS-ASM services. In this paper we analyze the AIS-ASM services and survey the extended functions and systems for each AIS-ASM service. We also present the survey of the statistical analysis of local AIS messages. and suggest preliminary research topics for the deployment of new AIS-ASM services. VDL monitoring system, system for detection and removal of malfunctioning AIS equipments, and value analysis process of the MSI services are required.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.443-451
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• 2017

This paper's objectives are to investigate the criteria for ergonomic evaluation of indoor bike coordinated with virtual images, and to compare HMD-based VR bike with 2D-based one. 12 experts performed delphi method with an aim to determine ergonomic evaluation criteria that were classified into 4 categories(Usability, Emotion, User Values, Reality). 2D-based bike and HMD-based one were compared according to part of final criteria through fuzzy-logic question performed by 20 subjects. Though there were no confidential difference in usability, HMD-based VR bicycle resulted in greater scores than 2D-based one in elements related with emotion, user value and reality statistically. It is expected that this research results will be used as references to evaluate ergonomic design of other indoor exercise equipments combined with VR or AR.

• Environmental Engineering Research
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• v.25 no.4
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• pp.479-487
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• 2020

Current assumptions are used in the formulation of pseudo-first (PFO) and second-order (PSO) models to describe the kinetic data of filtration based on ideal operating conditions. This paper presents a new model developed with pseudo n^th order and based on real assumption. A comparison was performed between PFO, PSO and the new model to highlight their performance and the optimisation of the pseudo-order equation, using MATLAB software. Adsorption characteristic of bovine serum albumin adsorption on the track-etched membrane are used as a medium based on protein filtration data were extracted from the literature for different concentrations to demonstrate the comparison between PFO/PSO and the new model. The pseudo first and second-order kinetic models were applied to test the experimental data and they did not provide reasonable values. The results show that the predicted values are consistent with experimental values giving a good correlation coefficient R² = 0.997 and a minimum root mean squared error RMSE = 0.0171. Indeed, the experimental results follow the new model and the optimal pseudo equation order n = 1.115, the most suitable curves for the new model. As a result, we used different experimental adsorption data from the literature to examine and check the applicability and validity of the model.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.7
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• pp.1129-1136
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• 2008

The gaiter is one of the personal protective equipments worn in various industrial sites. This study was performed on humans to investigate the physiological strain of wearing gaiters and to compare control gaiters that are currently on the market and new gaiters that are developed for alleviating heat stress. Experiments were conducted in a climatic chamber of WBGT $30.0\pm0.7^{\circ}C$ under five differed experimental conditions: None, Control A, Control B, New A, New B. The results were as follows. The temperature inside gaiters was significantly lower in both New A and New B than in both Control A and Control B and the difference between news and controls was 1$^{\circ}C$ (p<.01). The humidity inside gaiters in both New A and New B were higher than that in Control A, and lower than that in Control B (p<.01). The outermost surface temperature of the gaiter was the lowest in None and it increased in the following order: New B < New A < Control A < Control B. Mean skin temperature was higher by 0.14$^{\circ}C$ in wearing gaiters than in no gaiters. Skin temperatures in lower body were lower in Control than in New and skin temperature in upper body were higher in Control than in New (p<.01). Local sweat rate, total weight loss and subjective sensations did not show a significant difference according to the gaiters. It was concluded that wearing gaiters affected distribution of skin temperature and local sweat rate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.87-92
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• 2003

In rocket systems, somtimes special devices or equipments are installed near the nozzle exit area where high temperature and pressure combustion gas flows. To pretect these subsystems from severe thermal environment, it is necessary to have accurate thermal data measured from the experimental liquid rocket firing test. Test variables were combustion pressure (200, 300, 400 psi) and mixture ratio (1.5, 2.0, 2.5) and quartz was used as a heat probe. Measurement technique used in this research can be also applied to measure the radiative heat flux inside the combustion chamber which is important imput data for the liquid rocket regenerative cooling system design.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.3
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• pp.214-219
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• 1993

Counter balance valve is used as one part of hydraulic motor brake system. The function of this valve is to protect over-run or free falling of inertia load. But occasionally the brake system with counter balance valve makes some undesirable problems such as pressure surges or vibrations. These problems may hurt system safety and driver's conformability. Nevertheless, studies on dynamic characteristics of hydraulic system including counter balance valve are very rare, so further accumulation of research results are required. In this study, for the purpose of easy estimation about dynamic characteristics of hydraulic system including counter balance valve, precise formulation describing fluid dynamics and valve dynamics under various boundary conditions were made. The equations obtained in the preceding process include some parameters that must be got experimentally. Flow coefficients of valve and choke are the most significant ones among the parameters. So these parameters are obtained experimentally in this study, and experimental equations obtained from the experimental data were used for numerical calculation. The equations were analysed by numerical integration using Runge-Kutta method, because the equations contain various nonlinear terms. From the numerical analysis, it was verified that the dynamic response of counter balance valve and pressure variation at each elements can be estimated very easily. So the analysing method developed in this study enabled very easy estimating the relation between the performances of counter balance valve and various physical parameters related to the valve. Conclusively, it is said that the results obtained in this study can be used very usefully to develop a new type counter balance valve or to apply the valve to actual hydraulic system for various industrial equipments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.4
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• pp.505-513
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• 2009

Recently, researches on the construction information for construction of high-tech cities are under performed. RTLS(Real-Time location system) for gathering the dynamic location information of construction resources in construction sites, such as workers, materials and equipments, is one of the developments. Especially, construction resources can be managed efficiently with the dynamic location information and the improvement of safety and the reduction of cost are expected. To introduce the RTLS to the construction sites, the installation location of AP(Access Point) must be simulated using the 3-dimensional visibility analysis considering the propagation distance of AP. In this research, 3-dimensional signal simulation software based on the spatial data using surveying terrestrial LiDAR is developed. The simulated results are compared with the signal strength of field experiments for 4 test sites. As a result, the signal strength from the propagation model is most similar to that of field experiment at the front of the main building and the maul playground of Konkuk University. The visibilities in that sites are higher than other sites. among 4 test sites.