• Journal of the Korean Society of Radiology
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• v.3 no.3
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• pp.27-35
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• 2009

In this study, the basic research verifying possibility of applications as radiology image sensor in Digital Radiography was performed, the radiology image sensor was fabricated using double layer technique tio decrease dark current. High efficiency material in substitution for a-Se have been studied as a direct method of imaging detector in Digital Radiography to decrease dark current by using Hetero junction already used as solar cell, semiconductor. Particle-In-Binder method is used to fabricate radiology image sensor because it has a lot of advantages such as fabrication convenient, high yield, suitability for large area sensor. But high leakage current is one of main problem in PIB method. To make up for the weak points, double layer technique is used, and it is considered that high efficient digital radiation sensor can be fabricated with easy and convenient process. In this study, electrical properties such as leakage current, sensitivity is measured to evaluate double layer radiation sensor material.

• Composites Research
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• v.30 no.2
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• pp.116-125
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• 2017

The purpose of this study is to develop silicon carbide fiber showing an excellent mechanical properties under highly oxidative conditions at high temperature. Polycarbosilane(PCS) as a preceramic precursor was used for making the SiC fiber. PCS fiber was taken by melt spinning method followed by melting the PCS at $300{\sim}350^{\circ}C$ in N2 gas. The Curing of PCS fiber was carried out in air oxygen chamber, prior to high temperature pyrolysis. Degree of cure was calculated by characteristic peak's ratio of Si-H to $Si-CH_3$ in FT-IR spectra before and after curing of PCS fiber. The properties of SiC fiber was affected greatly by the degree of cure. The SiC fiber produced by controlling fiber tension during heat treatment showed good properties. The SiC fiber exposed to $1000^{\circ}C$ at air from 1 min. up to maximum 50 hrs showed around 60% reduction in tensile strength. We found that large amount of carbon content on the fiber surface after long-term exposure has resulted in lower tensile strength.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.148-148
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• 2017

방역 차량의 약액탱크, 차량의 연료, 워셔액 등의 탱크 내부에는 잔존량을 측정하기 위해 기둥과 floating box로 이루어진 부력식 수위레벨센서가 사용되고 있으나 액체레벨에 따라 float이 상하로 움직이는 측정원리상 차량 주행 중 정확성이 매우 떨어진다(Park et al. 2016). 방역차량이 주행 중 분사할 때, 슬로싱 현상과 방역소독기의 노즐과 펌프에서 발생하는 진동으로 인해 기존의 부력식 센서를 이용한 약제 살포량 측정방법은 정확성이 매우 떨어지는 경향이 있다. 본 연구의 목적은 방역차량이 주행하면서 분사할 때, 수위레벨 센서를 이용한 약제살포량 측정의 정확성을 개선하는 것으로 디지털 칼만필터, Low pass filter와 댐퍼를 제작하여 이용했다. 본 연구에서는 압력식 레벨센서를 이용해 약액탱크의 높이당 단면적과 수위를 측정하여 약제살포량을 계산했다. Python 2.7을 이용해 디지털 칼만필터와 Low pass filter(LPF)를 구현하였으며 3D프린터를 이용해 댐퍼를 제작했다. 실내에서 슬로싱 현상을 인공적으로 만들어 필터와 댐퍼의 수위 측정 정확성 개선효과를 확인 후 실제 방역차량에 부착하여 비포장도로에서 주행하면서 분사할 때 필터와 댐퍼의 효과를 확인하였다. 댐퍼의 공극률(p)을 바꿔가며 수위 측정 정확성 개선효과를 확인하였다. 실내, 현장 실험 결과, 칼만필터가 LPF보다 개선효과가 더 크지만 데이터 50개 처리에 1.71초의 시간지연이 발생했다. 댐퍼는 수위센서를 고정시키고 유체의 운동을 방해하여 이상치와 큰 오차제거에 효과적이었다. 칼만필터와 댐퍼를 동시에 이용할 경우, 수위 측정정확성 $R^2$는 0.9985, 0.9981로 ${\pm}4.3cm$의 범위내에서 수위를 측정할 수 있었다. 필터의 시간지연과 수위 측정정확성을 고려하여 데이터 기록간격을 3초로 설정하면 ${\pm}3cm$이내에서 약탱크 내 수위를 측정할 수 있었다. 공극률(p)가 0.294, 0.291, 0.17에서 측정정확성 $R^2$는 각각 0.9897, 0.9858, 0.9872 로 p가 0.294에서 개선효과가 가장 좋았으나 개선효과의 차이는 크지 않았다.

• KDI Journal of Economic Policy
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• v.14 no.3
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• pp.97-124
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• 1992

The recent sharp increase in wages has driven many Korean manufacturing firms to move into technology-intensive fields. The task of industrial restructuring is, however, rather difficult for small and medium-sized enterprises (hereafter, "SMEs") which suffer from limited R&D resources. If the R&D activities of SMEs are left unattended, industrial restructuring process may be retarded. Hence, the government-sponsored programs can be justified when used to promote the technological level of SMEs. Because of the limited internal R&D resources of SMEs, in particular human resources, the government-sponsored programs that depend on financial subsidies to stimulate the R&D activities of SMEs may not be recommended. Rather, a more desirable policy is programs to subsidize outside sourcing of SMEs. Basic principles of the program are; (i) that the government should establish R&D laboratories which are specialized in joint researches with SMEs in each industry; (ii) research projects of the laboratories should be funded by SMEs; the government's support covers only fixed costs such as construction costs in order to avoid moral hazard problem. (iii) technology adviser programs sponsored by the government should be improved; geographical distribution is to be expanded and the activities are to be monitored by local governments. Also foreign networks need be strengthened.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.307-317
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• 2011

Game character customizing has evolved with the desires of users who want to enjoy the scarcity value; thereby, the category which is subjected to character customizing is extending. However, despite such a great interest, character customizing interface has been created for the sake of the convenience of each game developing company, without proven guidelines. The confusion of designers who create interface is caused by using independently created interface without testing the optimal form of interface according to manipulative activity which integrates game character customizing interface, and this confusion leads to the discomfort of users. All the more, studies on character customizing have been mostly concerned with the preference for certain characters according to user propensity or character producing methods. Therefore, basic research into interface relative to character customizing is insufficient. Accordingly, through the development of universal guidelines appropriate for game character customizing interface. the discomfort of users is to be removed. This paper conducted an investigative analysis of the current interface of games which support character customizing, and classified the type of interface. Then, the paper researched 16 types of games that support character customizing out of games ranked within top 50 in the on-line game ranking. As a result of the analysis, the characteristic feature of every game appeared in the offer of detailed optional factors. Those detailed optional factors could be classified, to some extent; however, their manipulative interfaces were discovered not to be classified into different types. The results of this paper will be used as an analytic system in the preparation of the guidelines of game character customizing interface, down the road.

• Journal of Technology Innovation
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• v.23 no.3
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• pp.201-223
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• 2015

Existing research on international standardization has largely taken a qualitative approach focusing on comparative studies of national institutions and policies on standards or international rivalries from the perspectives of international relations or innovation studies. While there exists a handful of quantitative studies, they are mostly confined to simple numeric counts of essential patents, new work item proposals, or secretaries staffing international standards development organizations (SDOs). This study aims to contribute to our understanding of the dynamics of international standardization by the analysis of the data coding systematically national activities in the standardization process of the International Organization for Standardization (ISO), by far the largest international SDO. Our analysis of the four critical types of standardization documents generated in the Working Group 7 of the ISO/IEC Joint Technical Committee 1 reveals interesting dynamics among key players of global ICT standards regime. First, while the US takes a dominant share of the personnel as well as new work item proposals for standardization, its quality of activities rather falls behind as it mostly focuses on keeping in check other countries' standardization activities. Second, European countries tend to spread their effort evenly across different types of standardization activities. Finally, despite such differences between the US and European countries, both rely heavily on multinational companies to gain an advantage in the voting stage of standardization process.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2037-2046
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• 2000

It has been reported that the inhibition effect of pH on activated sludge follows noncompetitive inhibition kinetics. However. the noncompetitive inhibition kinetic equation can not be directly applied to pH inhibition because of the difficulty in quantification of pH in terms of inhibitor concentration. So, many empirical equations have been developed to describe the pH inhibition effect especially for acidic condition. In this research. the pseudo toxic concentration ($C_{PT}$) concept model to quantify pH inhibition effect on activated sludge was proposed and compared to other existing models. The $C_{PT}$ concept model can explain the reduction of the maximum specific growth rate (${\mu}_{max}$) caused by the pH inhibition more accurately than any other models, at a wide range of pH. The only model parameter. $K_I$ can be easily estimated by Lineweaver-Burk linearization method.

• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.550-566
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• 2018

In the era of the 4th industrial revolution, enhancing achievement evaluation based on process oriented instruction is essential. It assists human growth both cognitively and mentally. The purpose of this study is to analyze current condition of high school achievement evaluation in Daejeon region for enhancing English class based on achievement Assessment. Analyzing high school achievement evaluation plans as well as analyzing items of paper and pencil test using TELL program was conducted. Reanalysis of global citizen theme-based English according to core achievement standard was performed. The questionnaire was analyzed using the SPSS Win 20.0 Program to figure out significant difference of instructional method, the rate of students' grade improvement, English class related to the state of career recognition. T-test, ANOVA was performed to determine if there was a difference between the individual instructional variables. The research result is designed to construct or develop English class based on achievement evaluation while providing each high school with the result of current state of high school achievement evaluation. Specific characteristics of individual achievement result was conducted in terms of analyzing distribution of answer sheet response in order to be used as information for managing each high school achievement evaluation.

• Journal of Conservation Science
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• v.27 no.2
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• pp.201-209
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• 2011

While consolidants based on tetraethoxysilane (TEOS) have been widely used for the consolidation of decaying stone heritages, TEOS-based consolidants suffer from practical drawbacks, such as crack formation of the gel during the drying phase due to the developed capillary force. We have prepared new TEOS-based consolidants containing flexible (3-glycidoxypropyl) trimethoxysilane (GPTMS) in order to reduce capillary force development during gel drying. In this study, we have prepared TEOS/GPTMS-based consolidants containing ETEOS in order to improve the surface hydrophobisity. The physical properties of the TEOS/GPTMS/ETEOS solution with different hydrolysis were compared with those of the commercial products Wacker OH$^{(R)}$. The contact angle of the surface increased with the addition of the ETEOS, which is higher than that of Wacker OH$^{(R)}$. The sol-gel mechanism was manipulated by the degree of hydrolysis as well as the amount of ETEOS. The properties and the applicability of the developed consolidants for the decayed Korean granites are also investigated.

• Current Research on Agriculture and Life Sciences
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• v.15
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• pp.123-131
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• 1997

The alternation of light transmissivity of covering films used in most greenhouses over years become of concern. Recently, durable films over 0.1mm in thickness which having 3~5 years life time were popularly used in many greenhouses. However, the films have been replaced yearly with new ones because of lowering light transmittance. The replacement caused negative environmental impact as well as cost increasement. This study was conducted to find fundamental data for developing of a cleaning machine for covering films of greenhouses.