• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.36-42
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• 2016

In multi-level-cell based storage devices, TLC NAND has been employed solid state drive due to cost effectiveness. Since TLC has slow performance and low endurance compared with MLC, TLC based storage has adopted SLC buffer scheme to improve performance. To improve SLC buffer scheme, this paper proposes page overwriting method in SLC block. This method provides data updates without erase operation within a limited number. When SLC buffer area is filled up, FTL should execute copying valid pages and erasing it. The proposed method reduces erase counts by 50% or more compared with previous SLC buffer scheme. Simulation results show that the proposed SLC buffer overwrite method achieves 2 times write performance improvement.

• Journal of Environmental Health Sciences
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• v.43 no.5
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• pp.382-392
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• 2017

Objectives: The purpose of this study is to obtain basic data on the development of a risk communication model through an investigation of risk perception for radon and identify effective risk communication channels. Methods: A questionnaire was used to evaluate differences in perception level according to respective communication channels. A chi-squared test was used to analyze the difference in pre- and post-risk communication by communication channel. One-way ANOVA was used to analyze the difference in the radon risk perception rate for each communication channel. Results: All of the communication channels resulted in increased radon risk perception, but there was no statistical difference between them in terms of perception (p>0.05). However, based on previous findings that it is effective to use a multi-channel approach, it is considered that communication channels based on duplicate avenues is most appropriate. Conclusions: It is expected that this study will be used as basic data to better understand the formation of public opinion about radon risk and to understand the social reaction to each risk factor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.131-139
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• 2011

In this paper, we propose a double-faced window printed antenna for aircraft applications. The proposed antenna structure consists of a feeding line and a multi-loop radiator located on different sides of the window to use the limited given-area effectively. The proposed antenna is optimized by the genetic algorithm in conjunction with the FEKO EM simulator. The optimized antenna is built and installed on a 1/10 sized KUH-Surion mock-up and antenna performances such as the reflection coefficient and the radiation patterns are measured. The optimized antenna shows a half power matching bandwidth of about 33 % at 60 MHz and an average bore-sight gain of about -3.49 dBi. To verify the reception capability of the optimized antenna, we simulated the received power according to a flight scenario. The result confirms that the optimized antenna shows a minimum received power level above -60 dBm at a range of 200 km, which is similar to the pole antenna that is currently used as a FM voice antenna for KUH-Surion.

• Child Health Nursing Research
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• v.9 no.1
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• pp.18-27
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• 2003

The purpose of this study is to compare the educational needs and perception of mothers of normal neonates and high risk infants. This research was designed as a descriptive study. Data were collected for two months from April 2002 to March 2002. Subjects were 41 mothers of high risk infants and 60 mothers of normal neonates in one general hospital in Seoul participated in the study. Measurement tools used in this study were the educational needs scale developed by Cho Kyoul Ja et al and the neonatal perceptive inventories scale developed by Broussard. They ask mothers to rate each item on a four point Likert type scale. The collected data were analyzed using SPSS 8.0 program. The variables were listed as frequency, mean, standard deviation, X2 test, t-test, ANOVA. The results were as follows: The educational needs of the mothers of primi pregnancy was higher than the mothers of multi pregnancy. The educational needs on management of diseases such as prevention of infection, symptoms of disease, mental development, attachment promotion, congenital metabolism test, management of convulsion, care of vomiting and fever were higher than general care of infants such as immunization, measurement of temperature, hiccough care, follow up care. The informations must be included in nursing intervention program to reduce the mothers' stress level. In conclusion, in order to promote positive mother infant relationship, nurse need to give information and educate the mothers of high risk infant and normal neonate.

• Korean Journal of Social Welfare
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• v.69 no.3
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• pp.97-119
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• 2017

There has been no studies that compare services of residential care centers, group homes, and foster homes although out-of-home care services differ from each other depending on the types of out-of-home care. This study compared care satisfaction of 481 children in residential care centers, group homes, and foster homes for five years. Futhermore, factors that predict care satisfaction of the children were identified using multi-level modeling analyses. As results, this study found that care satisfaction of children in group homes was the higher than that in foster homes and residential care centers. In addition, self-esteem, social support, and types of out-of-home services were identified as significant predictors of changes in care satisfaction. Based on the study results, suggestions to help children adapt to out-of-home care and improve out-of-home care satisfaction were made.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.687-697
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• 2004

This paper is aimed to guide ocean-going companies to reasonable decisions and to increase the competitiveness of Korean shipping industry by clarifying the determinants of political costs of ocean-going companies, which only depend for the enormous amount of money to introduce the operating fixed assets, or the vessels, upon the supporting policy from the government or the loan from the related financial institutions. As independent variables of the political costs, 5 elements were settled such as company size(sales, total assets and market share), debit ratio, capital concentration ratio, profitability(operating profit) and marine risk(sales fluctuation). To verify the relations and the effect level between dependent variables and political costs, the Multiple Regression Analysis Model was applied The result of the analysis shows significantly positive relations between size variables and political cost of shipping industry. Moreover, debt ratio and profitability were proved significant related with political costs of shipping industry.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.485-486
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• 2007

Wireless Sensor Networking is state of the art technology that has a wide range of potential applications. Sensor network generally consists of a large number of distributed nodes that organize themselves into a multi-hop wireless network. Each node has one or more sensors, embedded processors and low-power radios, and is normally battery operated because of small size. In this paper wireless sensor networking technology applies to the environment monitoring system in the underground. This system can monitor a pollution level of the underground in realtime for keeping up a comfortable environment.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.777-786
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• 1995

This paper describes several algorithms for technology mapping of logic functions into interesting and popular FPGAs that use look-up table memories. In order to improve the technology mapping for FPGA, some existing multi-level logic synthesis, decomposition reduction and packing techniques are analyzed and compared. And then new algorithms such as node-pair decomposition, merging fanin, unified reduction and multiple output decomposition which are used for combinational logic design, are proposed. The cost function is used to minimize the number of CLBs and edges of the network. The cost is a linear combination of each weight that is given by user. Finally we compare our new algorithm with previous logic design technique［8］. In an experimental comparison our algorithm requires 10% fewer CLB and nets than SIS-pga.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.264-269
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• 2012

Die slide injection marvelously reduces the cost and time in processing plastic products because they can simplify the conventional process through eliminating additional process. However, this process must resolve some defects like whitening, resin infiltration, blowhole, resin overflow, etc. In this study, the process parameters of the injection molding are optimized by using the finite element method and Taguchi method. The injection molding analysis is simulated by employing the Moldflow insight 2010 code and the 2nd injection is by adopting the Multi-stage injection code. The process parameters are optimized by using the $L_{16}$ orthogonal array and smaller-the-better characteristics of the Taguchi method that was used to produce an airtight container (coolant reservoir tank) from polypropylene (PP) plastic material.rodanwhile, the optimum values are confirmed to be similar in 95% confidence and 5% significance level through analysis of variance (ANOVA). rooreover, new products and old products were compared by mdasuring the dimensional accuracy, resulting in the improvement of dimensional stability more than 5%.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.607-624
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• 2018

We review SAFT equation of state (EOS) which is based on TPT theory and statistical-mechanical principles, and confirm that it can be used as a useful tool to predict vapor-liquid phase equilibria of associating fluid mixtures. We examine theoretical structure of PC-SAFT EOS in great detail, and then assess the applicability and performance of the EOS while applying it to various mixtures containing nonpolar components, polar components and associating components in a stage-wise manner. In contrast to the conventional engineering EOS, PC-SAFT EOS can accurately predict nonideal behaviors of those mixtures without using semi-empirical binary interaction parameter. This is because the SAFT theory is based on a rigorous theoretical framework at molecular level which effectively accounts for various intermolecular interactions, and it thus provides substantial benefits in applying the SAFT EOS to complex thermodynamic phenomena of multi-component mixtures.