• Fire Science and Engineering
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• v.26 no.4
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• pp.24-30
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• 2012

The purpose of this study is to analyze the problem in measuring the differential pressure between the fire area and the neighboring smoke control zone as well as the opening force of a fire door and to present the actual values measured by an objective method. NFSC 501A specifies that the force necessary to open an access door when operating a smoke control system shall be less than 110 N. When the smoke control system does not operate in the space where it is installed, the door opening force can be measured by the test method in KS F 2805. However, when the smoke control system operates, additional opening force is required to overcome the force generated by the differential pressure between the fire area and smoke control room. Therefore, it can be seen that the method proposed by the standard has insufficient reliability. The analog measuring device and digital measuring device showed that the opening forces, $F_a$ and $F_d$, of the fully closed door before the smoke control system were 27.8 N and 27.4 N, respectively. When the door remained open by $5^{\circ}$, the opening forces, $F_a$ and $F_d$, were 33 N and 33.6 N, respectively. When the smoke control system operated and the door was fully closed, the door opening forces, $F_a$ and $F_d$, were 77.6 N and 76.0 N, respectively. Therefore, since the door opening forces are different from the criteria presented by KS F 2805, it is required to review the criteria appropriately.

• Journal of KIISE:Information Networking
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• v.33 no.6
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• pp.407-419
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• 2006

As substituting IPv6 network for all IPv4 network in a short time seems unattainable due to high cost and technical limitation, IPv4 and IPv6 are expected to coexist for a certain period of time. Under the co]existing environment of IPv4 and IPv6, interworking brings a number of extra security considerations even if it may have no security problem for each protocol respectively. Thus, the analysis and solutions for those various attacks toward IPv4/IPv6 interworking-related security are inevitably required for the sake of effective transition and settlement to IPv6. In this paper we carried out a proper rule of packet filtering for IPv6-in-IPv4 tunneling interworking environment to protect the IPv4/IPv6 interworking-related security attacks. Design and implementation of the packet filtering system suitable for IPv4/IPv6 tunneling environment in the form of Linux netfilter and ip6tables are also shown. Thru this study, the packet filtering system was found operating correctly ill the tunneling mechanism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.112-119
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• 2016

This study aims to examine propping by the controlling shareholders and the corporate value of Korean firms with agency problems and propping perspectives. Propping refers to a transfer of resources from a higher ownership firm to a lower ownership firm, in order to prevent the latter from going bankrupt. This study used a sample of 4,077 companies listed on the KRX data exchange from 2004 to 2014. We used proxy variables such as long-term supply contracts, asset and business sales, credit facilities, loans, and equity investments to affiliates as wealth transfer instruments of the controlling shareholders. We found that propping occurred by the equity investment of affiliates in Korean firms. Also, we found that the Korean firm's value was decreased by the affiliate equity investment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.201-208
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• 2017

Recently, the installation of photovoltaic(PV) systems has been increasing due to the worldwide interest in eco-friendly and abundant solar energy. On the other hand, a PV system has approximately 25% power loss while the energy generated from solar cells is transformed to the power coupling point through a power conversion system (DC/AC). If the output voltage of a string in the PV system is lower than the operating range of the inverter when a part of module in the string has a shadow due to weather conditions, the string is not synchronized and the whole efficiency of output power in a PV system may be reduced significantly. Therefore, to overcome this problem, this paper proposes a novel control method to compensate for the lower voltage by introducing a DC/DC voltage regulator for each string in a PV system, which adopts a concept for MPPT (Maximum Power Point Tracking) control function using the P&O algorithm and adopts constant voltage control method used in an existing inverter. This paper also implements a 2kW DC/DC voltage regulator based on the proposed algorithm and performs a variety of scenario-based experiments. From the simulation result, it was confirmed that the operation efficiency in the proposed method is improved compared to the existing method.

• Journal of Nutrition and Health
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• v.38 no.7
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• pp.533-543
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• 2005

The purpose of this study was to determine the iron status of preschool children in Ulsan, Korea. The study was con-ducted using 95 children aged 3 to 6 years by investigating the anthropometric indices and assessing the dietary intakes and biochemical analysis. A questionnaire for dietary intakes using 24-hr recall method were carried out by the mothers of the 95 subjects. And also a study was conducted to assess hematological and biochemical status of iron and prevalence of iron deficiency. The average height and weight were 105.4 $\pm$ 7.0 cm, 18.7 $\pm$ 3.2 kg in boys, 103.8 $\pm$ 6.7 cm, 17.6 $\pm$ 2.7 kg in girls. These were lower than the body growth standard values of Korean pediatrics. There was not a significant difference in both between boys and girls. For the daily nutrient intake, energy was 1201.5 $\pm$ 280.9 kcal (79.3$\%$RDA), protein was 63.8 $\pm$ 28.2 g (219.4$\%$RDA), iron was 11.9 $\pm$ 4.5 mg (133.2$\%$RDA). The iron nutritional status by hematological assay found that Hct was 34.7 $\pm$ 2.0 ($\%$), Hb was 12.0 $\pm$ 0.8 g/dl, RBC was 4.3 $\pm$ 0.3 ($10^6/{\mu}l$), MCV was 80.5 $\pm$ 3.0 fL, MCH was 27.8 $\pm$ 1.1 pg and MCHC was 34.6 $\pm$ 0.6 g/dl. The biochemical measurement of serum iron was 75.6 $\pm$ 30.3 ${\mu}g$/dl, TIBC was 320.3 $\pm$ 34.1 ${\mu}g$/dl, serum ferritin was 30.0 $\pm$ 14.8 ${\mu}g$/dl, Zinc-Protophor-phyrin (ZPP) was 32.7 $\pm$ 8.0 ${\mu}g$/dl, and ZPP/Heme was 71.1 $\pm$ 19.5 ($\mu$mole/mol heme). The prevalence with Hct, Hb, TS and serum ferritin less than cut-off value was $8.4\%,\;9.5\%,\;12.6\%$ and $4.4\%$ respectively. But the prevalence of iron deficiency estimated with ZPP and ZPP/Heme criteria were $25.3\%$ and $27.4\%$, and were higher than in case of any other indices. The prevalence of iron deficiency anemia ((low Hb (< 11.0 g/dl) and low serum ferritin (< 10 ${\mu}g$/L) or low TS (3-4 yews: < $12\%$, 5-6 years: < $14\%$)) was found in only one 3 year old girl. The prevalence of iron deficiency except Hct and Hb was the highest in 3 year group, but the prevalence by Hct and Hb was the highest in 5 year group. Iron deficiency and iron deficiency anemia do not seem to be a major public health problem in preschool children in Ulsan.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.16-27
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• 2006

The wireless transmission medium inherently broadcasts a signal to all neighbor nodes in the transmission range. Existing asynchronous MAC protocols do not provide a concrete solution for reliable broadcast in link layer. This mainly comes from that an omni-directional broadcasting causes to reduce the network performance due to the explosive collisions and contentions. This paper proposes a reliable broadcast protocol in link taller based on directional antennas, named MDB(MAC protocol for Directional Broadcasting). This protocol makes use of DAST(Directional Antennas Statement Table) information and D-MACA(Directional Multiple Access and Collision Avoidance) scheme through 4-way handshake to resolve the many collision problem wit]1 omni-directional antenna. To analyze its performance, MDB protocol is compared with IEEE 802.11 DCF protocol [9] and the protocol 2 of reference [3], in terms of the success rate of broadcast and the collision rate. As a result of performance analysis through simulation, it was confirmed that the collision rate of the MDB protocol is lower than those of IEEE 802.11 and the protocol 2 of reference [3], and that the completion rate of broadcast of MDB protocol is higher than those of IEEE 802.11 and the protocol 2 of reference [3].

• Journal of Distribution Science
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• v.4 no.2
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• pp.5-20
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• 2006

Retail is called location business because it is one of the most important factors to estimate management of stores for retailers who are going to sell products directly to customers. Retailers' management achievements are shown in sale in general. Therefore, retailers tend to focus on ways to increase the numbers of customers in order to raise sales. First of all, in this research, I am going to examine the most fundamental models such as Reilly's retail gravitation, converse model, huff probability model and multiful losit model in selecting stores. Secondly, I am going to provide the process and analyzing ways to predict estimated sales amount with the previous theory model. Also I am going to predict estimated sales amount of the department store L which is located in D metorpolitan city. Lastly, I am going to argue about the problem of this research and the next research subject. Our main goal is to provide ways to complement and inspect sales estimation models, which can be used in fields after taking characters of high class structure of Korea into consideration on the base of previous researches. According to the result of the research, my conclusion is that if the process of analysis and changing factors are complemented, revise model, which can reflect reality of Korea, will be provided. Therefore, in the future study, we have to build up theory models to suit for our retail market through critic reviews about the existing high class structure of Korea.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2761-2765
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• 2016

Opisthorchiasis is a health problem in rural communities of Thailand, particularly in the northeast and north regions. Therefore, this study aimed to investigate raw fish consuming behavior related to liver fluke infection among the population at risk for opisthorchiasis and cholangiocarcinoma (CCA). A cross-sectional descriptive study was conducted in Meuang Yang district, Nakhon Ratchasima province, northeast Thailand, between June and October 2015. Participants were screened for CCA, and samples who had a high score of CCA risk were purposively selected. A predesigned questionnaire was utilized to collect the data from all participants. $X^2-test$ was used for analysis of associations between demographic data and raw fish consumption. The results revealed that participants had past histories of stool examination (33.0%), liver fluke infection (21.0%), praziquantel use (24.0%), raw fish consumption (78.0%), relatives family consuming raw fish (73.0%), and relatives family with CCA (3.0%). Participants consumed several dished related to liver fluke infection, mainly raw fermented fish (13.0%), under smoked catfish (5.00%), raw pickled fish (4.00%), and raw spicy minced fish salad (3.00%). The most common types of cyprinoid fish were Barbodes gonionotus (39%), Hampala dispar (38%), Puntius brevis (37%), Cyclocheilichthys armatus (33%), Puntioplites proctozysron (32%), and Luciosoma bleekeri (30%), respectively. Participants had a low level of knowledge (mean=3.79, SD=0.74), moderate attitude (mean=7.31, SD=7.31) and practice (mean=38.64, SD=6.95) regarding liver fluke prevention and control. Demographic variables like age (>36 years old; $X^2-test=17.794$, p-value=0.001), education (primary school; $X^2-test=18.952$, p-value=0.001), marital status (married; $X^2-test=12.399$, p-value=0.002), and income (<5,000 baht; $X^2-test=27.757$, p-value=0.015) were significantly associated with raw fish consumption. This result indicates that the population had risk consumption for liver fluke infection particularly of various cyprinoid fishes that are $2^{nd}$ intermediate hosts. Therefore, health education is required to improve their behavior.

• The KIPS Transactions:PartD
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• v.10D no.2
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• pp.267-276
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• 2003

Many countries have established eBook standards adequate to their environments. In USA, OEB PS is announced for distribution and display of eBooks, in Japan, JepaX is announced for storage and exchange, and in Korea, EBKS is made for clear exchange of eBook contents. These diverse objectives lead to different content structures. These variety of content structure will cause a problem in exchanging them. To correctly exchange eBook contents, the content structure should be considered. So, In this paper, we study conversion methods of standard eBooks contents based on Korean eBook standard, with contemplating content structure. To convert contents properly, the mapping relations should be clearly defined. For this, we consider standard's structure and extension mechanisms, and use path notations and namespaces for precise description. Moreover, through analysis of each mapping relationships, we classify conversion cases into automatic, semi-automatic, and manual conversions. Finally we write up conversion scripts and experiment with them.

• Journal of the Korean Institute of Gas
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• v.7 no.4 s.21
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• pp.44-52
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• 2003

In this work dynamic heat transfer in a CPFS (cable penetration fire stop) system built in the firewall of nuclear power plants is three-dimensionally investigated to develop a test-simulator that can be used to verify effectiveness of the sealant. Dynamic heat transfer in the fire stop system is formulated in a parabolic PDE (partial differential equation) subjected to a set of initial and boundary conditions. First, the PDE model is divided into two parts; one corresponding to heat transfer in the axial direction and the other corresponding to heat transfer on the vertical planes. The first PDE is converted to a series of ODEs (ordinary differential equations) at finite discrete axial points for applying the numerical method of SOR (successive over-relaxation) to the problem. The ODEs are solved by using an ODE solver In such manner, the axial heat flux can be calculated at least at the finite discrete points. After that, all the planes are separated into finite elements, where the time and spatial functions are assumed to be of orthogonal collocation state at each element. The initial condition of each finite element can be obtained from the above solution. The heat fluxes on the vertical planes are calculated by the Galerkin FEM (finite element method). The CPFS system was modeled, simulated, and analyzed here. The simulation results were illustrated in three-dimensional graphics. Through simulation, it was shown clearly that the temperature distribution was influenced very much by the number, position, and temperature of the cable stream, and that dynamic heat transfer through the cable stream was one of the most dominant factors, and that the feature of heat conduction could be understood as an unsteady-state process.