• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.2
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• pp.240-252
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• 1998

The purpose of this study is to develop a method for predicting the aerodynamic performance of the low speed airfoils in the 2-dimensional, steady and viscous flow. For this study, the airfoil geometry is specified by adopting the longest chord line system and by considering local surface curvature. In case of the inviscid incompressible flow, the analysis is accomplished by the linearly varying strength vortex panel method and the Karman-Tsien correction law is applied for the inviscid compressible flow analysis. The Goradia integral method is adopted for the boundary layer analysis of the laminar and turbulent flows. Viscous and inviscid solutions are converged by the Lockheed iterative calculating method using the equivalent airfoil geometry. The analysis of the separated flow is performed using the Dvorak and Maskew's method as the basic method. The wake effect is also considered by expressing its geometry using the formula of Summey and Smith when no separation occurs. The computational efficiency is verified by comparing the computational results with experimental data and by the shorter execution time.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.7
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• pp.73-84
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• 2020

Existing studies disagree over the core predictors of firm-level financial choices in developing countries. The general practice only validates the traditional capital structure model, which leads to inconsistency and a lack of novelty. This study removed overfitting issues among existing factors and presented the most reliable and advanced capital structure model in Pakistani firms. The panel data include 368 Pakistani companies from 19 non-financial sectors over the period 2004 to 2017. We apply Akaike and Bayesian Information Criteria to remove overfitting issues among inconsistent proxies in the capital structure model. The fixed effects regression is used for basic results and the Generalized Method of Moments is applied to control the endogeneity. Besides the conventional proxies, we report that credit rating, distance from bankruptcy, managerial concentration, and institutional quality are the most advanced capital structure determinants in Pakistan. These predictors remain significant across firm size and growth levels. Also, the findings confirm that new predictors are reliable to define capital structure dynamics and improve the speed of adjustment in overall and sub-sample analysis. The major findings suggest that managers and policymakers should consider these advanced predictors to design their financial settings in firms.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.376-384
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• 2021

This study wants to provide basic data on effective escape safety plans when residents of apartment complex use residential convenience facilities. The findings of the analysis are as follows. First, when this study applied the actual number of users (No=54) of those facilities, the existence of elevator for escape reduced the escape time by 189.0 seconds. Second, when the number of users was calculated on the standard of the number of people who can be accommodated for performance based design (No=316), the existence of the elevator for escape reduced the escape time by 173.5 seconds. Finally, when the number of users was calculated on the standard of installing fire-fighting facilities (No=122), the existence of the elevator for escape reduced the escape time by 159.2 seconds. As a result, it was found that elevator for escape reduces the escape time from fire. Accordingly, it is necessary to revise the construction law to make it obligatory for residential convenience facilities to be equipped with elevator for escape. Currently, apartment buildings lower than 30 stories have either elevator for passengers or elevator for escape. Thus, in future studies, it is necessary to compare escape times in fire depending on the kinds of elevator, and identify the usefulness of elevator for escape.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.449-455
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• 2022

Objectives: In order to provide basic data for future researchers, this study aims to explore future tasks after reviewing the changes in port safety management due to the enforcement of the Special Act on Port Safety. Methods: The provisions of the Special Act on Port Safety were analyzed and the latest literature related to port safety management was reviewed. Results: There are two major changes that have stemmed from the Special Act on Port Safety: 1. The scope of application for port participants has been expanded, safety education has been made compulsory, and safety management plans have been established and implemented for each business site. 2. The government is operating a port safety consultative body for each port and has hired one port safety inspector for each of the eleven local maritime and fisheries offices across the country. Future tasks include elaboration of port safety accident statistics, strengthening shipping companies' responsibility for stevedore safety, the unification of contracts, and government interest and support for port safety facilities. Conclusions: The primary feature of the Special Act on Port Safety is the emphasis on autonomous safety management by participants in port transportation. In addition, the enactment of the special law has allowed the Ministry of Maritime Affairs and Fisheries to actively intervene in port loading and unloading safety.

• Journal of the Korean Institute of Rural Architecture
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• v.24 no.1
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• pp.1-8
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• 2022

Among Korea's national folk cultural heritage, eight villages have been designated, and 37 years have passed since Hahoe Village was first designated in 1984. All eight villages have been constantly inhabited by residents from the past to the present, so the cultural value of inferring the lives of our ancestors in the past is very high. However, due to the inconvenience of the settlement environment in existing houses due to changes in the living environment, buildings such as various residential facilities and warehouses have been installed and expanded without permission, losing the original cultural property landscape and building. In addition, complaints and conflicts from residents are accumulating due to the poor living environment in the village. Therefore, this study intends to present guidelines for conservation and maintenance that can embrace changes in resident's housing and living environment, based on the 'maintenance of original form', the grand principle of the Cultural Properties Protection Law about the Jeju Seongeup Village. In particular, the maintenance plan is largely subdivided into legalization, demolition, expansion and reconstruction, and detailed standards for each item and examples applied are proposed. Through this, it aims to become basic data on the starting point of realistic improvement measures for cultural properties and residents to coexist.

• Journal of The Korea Institute of Healthcare Architecture
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• v.30 no.1
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• pp.7-17
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• 2024

Purpose: This study is to present basic data and standards for calculating the space composition and area required when planning a neonatal intensive care unit. Methods: Review domestic and foreign facility standards and regulations related to the current neonatal intensive care unit, select a regional neonatal intensive care center designated by the Ministry of Health and Welfare as a case hospital, and organize a space program for the construction plan of the neonatal intensive care unit through analysis of characteristics such as facility size and function composition. Results and Implications: The size, facility area, and detailed room composition characteristics of the neonatal intensive care unit in Korea were confirmed, and essential rooms and appropriate areas were derived when planning the construction of the neonatal intensive care unit. Korea's legal facility standards related to neonatal intensive care units are lower than the actual hospital status and overseas standards, and the facility standards of the medical law need to be improved.

• Journal of Mechanical Science and Technology
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• v.16 no.6
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• pp.839-850
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• 2002

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components'characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the turbine inlet temperature occurred. However, in case of ramp increase of the fuel longer than step increase of the fuel, the overshoot of the turbine inlet temperature was effectively reduced.

• International Commerce and Information Review
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• v.6 no.2
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• pp.107-127
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• 2004

The rapid development of internet information technology has increased interest in e-Trade these days, but it is not activated greatly up to now. In order to promote e-Trade, it is essential to construct cooperative process such as connecting systems among trade related parties. Building e-Trade platform which is based on the infrastructure of the past trade automatic system is key point of promoting e-Trade. To do this, a study on the basic concept and specific components of e-Trade platform is needed absolutely. At this point of view, after this paper has examined domestic and foreign studies on the fundamental technologies about electronic commerce, it drew several key technologies that could be applied to e-Trade considering the current IT trend. Then it evaluates these technologies according to Technology Reference Model(TRM) of the National Computerization Agency. This will help us to show the operation strategy as well as the concept of future e-Trade platform and its composition. On the basis of the theoretical background, this paper classified NCA's technology model into 6 fields, which are application. data, platform, communication, security and management. Considering the key technologies, e-Trade platform has to be mutually connected and accept international standards such as XML. In the aspect of business side, trade relative agencies' business process as well as trading company's process has to be considered. Therefore, e-Trade platform can be classified into 3 parts which are service, infrastructure and connection. Infrastructure part is compared of circulating and managing system of electronic document, interface and service framework. Connecting service (application service) and additional service (application service) consist of service part. Connecting part is a linking mutual parts and can be divided into B2B service and B20 service. The organization operating this e-trade platform must have few responsibilities and requirements. It needs to positively accept existing infrastructure of trade automatic system and improving the system to complete e-trade platform. It also have to continuously develop new services and possess ability to operate the system for providing proper services to demanders. As a result, private sector that can play a role as TTP(Third Trust Party) is adequate for operating the system. In this case, revising law is necessary to support the responsibility and requirement of private sector.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.49-58
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• 2019

In the era of the 4th industrial revolution, the development of information technology brought various benefits, but it also increased social interest in privacy issues. As the possibility of personal privacy violation by big data increases, academic discussion about privacy management has begun to be active. While the traditional view of privacy has been defined at various levels as the basic human rights, most of the recent research trends are mainly concerned only with the information privacy of online privacy protection. This limited discussion can distort the theoretical concept and the actual perception, making the academic and social consensus of the concept of privacy more difficult. In this study, we analyze the privacy concept that is exposed on the internet based on 12,000 news data of the portal site for the past one year and compare the difference between the theoretical concept and the socially accepted concept. This empirical approach is expected to provide an understanding of the changing concept of privacy and a research direction for the conceptualization of privacy for current situations.

• Journal of the Korea Society of Computer and Information
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• v.28 no.3
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• pp.149-157
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• 2023

The purpose of this study is to suggest that performers in the performing arts actively utilize the loading dock and stage door when evacuating from the stage space of a performance hall in a crisis situation. Therefore, first, we analyzed the system related to the performance hall's safety. The stage evacuation type was classified into A, B, C, and D forms by applying the building law audience evacuation standards. Second, statistical data were organized based on measurement data, and the characteristics of each form were summarized. Third, the network reliability measurement method was borrowed to evaluate the evacuation safety of the evacuation route in the stage space. We confirmed quantitatively that the direction of the loading dock direction and stage door direction on the stage is advantageous for evacuation. In this study, it was possible to distinguish the advantage of evacuation according to the type of evacuation, (A(0.1274)>B(0.1228).>.C(0.0487)) with A being the most advantageous. These results can be expected to improve the evacuation safety of the stage, and furthermore, they are expected to be used as basic data for stage evacuation.