• Journal of Korean Society of Transportation
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• v.35 no.3
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• pp.197-209
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• 2017

With the advent of age that people spend more time and money on leisure activities, there is increasing interest in professional sport games. The location of large scale sport facilities has substantial impacts on existing transportation pattern because the facility attracts and generates massive traffic volume within a short period of time. This study aims to develop a mode choice model of leisure trips of which the destinations are a sport facility. A structured SP (stated preference) survey questionnaires were developed through an experimental design, and professional sport spectators were asked to state their preference in the choice of transport mode to the sport facility. The survey results show that public transportation is preferred to passenger cars for their trip to big sports event, implying that the convenience of back home trip after the event is an important factor of their mode choice. This study is a rare research on the trip pattern to sports complex in Korea, which provides policy implications on the provision of mass transit including subway system to large scale sport complexes. And it is also expected that this study contributes to future researches on leisure trip pattern.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.314-323
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• 2022

Vessel Traffic Services (VTS) operators perform traffic management tasks using VTS systems and sensor equipment designated as VTS facilities to promote the safety and efficiency of vessel traffic. The necessary VTS information for effective operations could be obtained through the additional access of various information channels other than the designated VTS facility. To unify these various information access windows, the development of the VTS cloud system is in progress. In this study, the operational information analysis for VTS was performed through VTS tasks-facility linkage analysis to identify the user required information according to the introduction of the VTS cloud system. The VTS task analysis was performed through research of the international and domestic literature, and expert interviews. The necessary information were identified and linked according to the VTS facilities. As a result of the analysis, 37 categories of necessary information were identified for internal and external information windows, and 8 information windows were selected other than the present VTS equipment. The identified user requirements would be applied to the structure design of the VTS cloud system. In the future, it is necessary to update user requirements through scenario-based user operation analysis and to conduct additional research on the system interface design.

• Wind and Structures
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• v.29 no.5
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• pp.323-337
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• 2019

Wind tunnel testing technique has been established as a powerful experimental method for predicting wind-induced loads on high-rise buildings. Accurate assessment of the design wind load combinations for tall buildings on the basis of wind tunnel tests is an extremely important and complicated issue. The traditional design practice for determining wind load combinations relies partly on subjective judgments and lacks a systematic and reliable method of evaluating critical load cases. This paper presents a novel optimization-based framework for determining wind tunnel derived load cases for the structural design of wind sensitive tall buildings. The peak factor is used to predict the expected maximum resultant responses from the correlated three-dimensional wind loads measured at each wind angle. An optimized convex hull is further developed to serve as the design envelope in which the peak values of the resultant responses at any azimuth angle are enclosed to represent the critical wind load cases. Furthermore, the appropriate number of load cases used for design purposes can be predicted based on a set of Pareto solutions. One 30-story building example is used to illustrate the effectiveness and practical application of the proposed optimization-based technique for the evaluation of peak resultant wind-induced load cases.

• Journal of the Korea Society of Computer and Information
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• v.28 no.1
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• pp.121-127
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• 2023

In this study, the design conditions and CFD analysis results are compared and reviewed in SCR that can optimally reduce nitrogen compounds. To this end, it was analyzed and compared using CFD to see if the design criteria were satisfied for the shell and tube areas of the boiler. In the SCR system, the analysis area is the gas/air heat exchanger on the shell side, and eight tubes of the gas/air heat exchanger on the tube side. Through CFD analysis, the gas velocity distribution on the primary catalyst side of the SCR system was designed to be 2.4%, and the NH3/NOx molar ratio distribution was 3.7%, which satisfied the design criteria. In addition, the uniformity of the temperature distribution was confirmed and the required condition of 260℃ or higher was satisfied. The angle of the gas entering the catalyst met the design conditions at 2.9 degrees, and the pressure loss that occurred also satisfied the design requirements. Through this CFD analysis, it was confirmed that it was designed and operated by satisfying the design conditions required for each area.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.1
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• pp.1-14
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• 2003

In this study, to take the object of this thesis on understanding the characteristics on marketing structure and marketing distribution of landscape materials after consideration in the side of prices trends which is important factors for analysis in understanding the market of landscape materials. To do this, Analysis is divided into the prices trends. The investigation of prices trends and marketing distribution are to collect data refer to purchases and sales reports, these results are used to analyzed the operative factor of forming market structure. The periodic range of this thesis is limited from 1996 to 2000 and analytic articles is limited on 609 landscape materials(planting materials : 567 articles, facility materials : 7 articles, the other : 35 articles). The results of the whole prices trends and marketing distribution survey can be summarized as follows : 1. Prices trends of showing 3 types of landscape materials : In cases of planting, facility and the others materials, the annual average increasing rate of the index number of price was 3.1%, 3.4%, 3.1% while the KPRC(Korea Price Research Center) price was 3.98% for the past five years. 2. GSP(Government Specified Prices) Prices trends of showing 3 types of landscape materials : In cases of planting, facility and the others materials, the annual average increasing rate of the index number of price was 3.7%, 1.2%, 2.6% while the KPRC(Korea Price Research Center) price was 3.98% for the past five years. This increase indicates a small price margin, particularly, the GSP price of planting materials should be adjusted to a realistic level. 3. Native and exotic product Prices trends of showing 3. types of landscape materials : In cases of Native planting, facility and the others materials, the annual average increasing rate of the index number of price was 3.2%, 3.2%, 3.6% while cases of exotic was 3.1%, 1.0%, 5.8% for the past five years. The index number increase of prices of exotic landscape materials were fluctuated more than those the native landscape materials.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.51-60
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• 2011

Purpose: This study was to investigate visual performance and subjective satisfaction with multifocal soft contact lenses at near works in university students. Methods: In a cross-over study design, 26 students (6 male, 20 female) who did not have any ocular disorder with at least 20/20(1.0) binocular vision were fitted with singlevision lenses (SofLens$^{TM}59$, Bausch + Lomb Co. USA) or multifocal lenses (SofLens Multifocal, Bausch + Lomb Co. USA). After 2 weeks, visual performance assessments included visual acuity, stereoacuity and contrast sensitivity function at distance and near. Near point of accommodation, accommodative facility, near point of convergence, vergence facility and near range of clear vision at near were examined. Students' satisfaction and preference were measured using survey questionaries. Results: Subjects maintained at least 20/20 binocular vision with multifocal and single-vision lenses at distance and near. There was no difference between multifocal and single-vision lenses in stereoacuity, contrast sensitivity function and vergence facility at far and near. The near point of accommodation, accommodative facility, near point of convergence and the near range of clear vision with multifocal lenses were better than single-vision lenses. On the survey questionaries, subjects reported that they preferred and satisfied with multifocal lenses with near works, and single-vision lenses with distance works. Conclusions: The majority of university students preferred multifocal to single vision lenses because multifocal lenses provided better visual performance at near works. This study suggests that multifocal lens is helpful for young adult in prolonged near works.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.452-459
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• 2023

The core power control is an important issue for the study of dynamic characteristics in China initiative accelerator driven subcritical system (CiADS), which has direct impact on the control strategy and safety analysis process. The CiADS is an experimental facility that is only controlled by the proton beam intensity without considering the control rods in the current engineering design stage. In order to get the optimized operation scheme with the stable and reliable features, the variation of beam intensity using the continuous and periodic control approaches has been adopted, and the change of collimator and the adjusting of duty ratio have been proposed in the power control process. Considering the neutronics and the thermal-hydraulics characteristics in CiADS, the physical model for the core power control has been established by means of the point reactor kinetics method and the lumped parameter method. Moreover, the multi-inputs single-output (MISO) logical structure for the power control process has been constructed using proportional integral derivative (PID) controller, and the meta-heuristic algorithm has been employed to obtain the global optimized parameters for the stable running mode without producing large perturbations. Finally, the verification and validation of the control method have been tested based on the reference scenarios in considering the disturbances of spallation neutron source and inlet temperature respectively, where all the numerical results reveal that the optimization method has satisfactory performance in the CiADS core power control scenarios.

• Journal of the Korean housing association
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• v.26 no.6
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• pp.181-190
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• 2015

This study emphasizes a new senior housing type which can provide individual housing units and common facilities for retirees, particularly who will be retired from universities. It is called a university-based retirement community. This study conducted a questionnaire survey to investigate future residents' needs for architectural environments that included housing types, common facility features, and proximity, and also development methods in response to the university involvement levels. The survey questionnaire was administered in one national university in Korea. A total of 214 responses were valid for statistical analyses. Major findings are as follows: Over 65% of the respondents were willing to live in the university-based retirement community. Regarding the location of the community, they responded the community would not need to be located on campus. Preferred common facilities in the UBRC were indoor fitness centers, the shuttle bus stops connecting to the adjacent areas, and bath and sauna facilities. The respondents emphasized university's contribution toward offering educational programs for UBRC residents. Lastly, their responses to the university role and involvement in the development and construction process were identified. This study results are expected to provide essential information for facilitating the Korean model of university-based retirement communities in the future.

• The Journal of Korean Association of Computer Education
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• v.10 no.4
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• pp.51-59
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• 2007

There is the meager level of applying computers to mathematics education. It is because the effective mathematics educational softwares and the various contents that make students' spontaneous participation through the interaction with computers are insufficient. As a solution to solve it, we design and implement the graphic component, graphic entities and function types that are supported in the component was identified through analyzing the mid/high school curriculum, using a simple script language to invoke the functionality of the component improves reusability and extendability. The component can be used to produce the mathematics educational softwares and contents easily that need the facility to draw various functions and geometric figures.

• Wind and Structures
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• v.36 no.4
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• pp.263-275
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• 2023

As a new kind of construction facility for high rise buildings, the integral steel platform scaffold system (ISPS) consisting of the steel skeleton and suspended scaffold faces high wind during the construction procedure. The lattice structure type and existence of core tubes both make it difficult to estimate the wind load and calculate the wind-induced responses. In this study, an aeroelastic model with a geometry scale ratio of 1:25 based on the ISPS for Shanghai Tower, with the representative square profile, is manufactured and then tested in a wind tunnel. The first mode of the prototype ISPS is a torsional one with a frequency of only 0.68 Hz, and the model survives under extreme wind speed up to 50 m/s. The static wind load and wind vibration factors are derived based on the test result and supplementary finite element analysis, offering a reference for the following ISPS design. The spacer at the bottom of the suspended scaffold is suggested to be long enough to touch the core tube in the initial status to prevent the collision. Besides, aerodynamic wind loads and cross-wind loads are suggested to be included in the structural design of the ISPS.