• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.314-315
• /
• 2011

최근에 $Eu^{3+}$ 이온이 첨가된 적색 형광체에 대한 연구가 활발히 진행되고 있다. 현재 상업적으로 이용 가능한 적색 형광체와 비교하여 $GdVO_4$를 모체로 갖는 적색 형광체는 우수한 열적 안정성과 광학적 특성을 나타낸다. 본 연구에서는 고효율의 적색 형광체를 개발하기 위하여 고상 반응법을 사용하여 $Gd_{1-x}VO_4$ : $Eu_x^{3+}$ 형광체를 합성하였다. $Gd_{1-x}VO_4$ : $Eu_x^{3+}$ 형광체 분말 시료는 활성체인 $Eu^{3+}$의 함량을 0, 0.05, 0.10, 0.15, 0.20 mol로 변화시키며, 초기 물질 $Gd_2O_3$ (99.99%), $H_3BO_3$ (99.99%), $Eu_2O_3$ (99.9%)를 화학 적량으로 준비하였다. 분말은 볼밀과 건조 작업을 거친 후, 500$^{\circ}C$ 전기로에서 5시간 동안 하소 공정, 1,100$^{\circ}C$에서 6시간 동안 소성시켰다. 합성된 형광체 분말의 XRD 측정한 결과에 의하면, $Eu^{3+}$의 함량비에 관계없이 모든 분말 시료들에서 주 피크는 24.7$^{\circ}$와 33.2$^{\circ}$에 최대값을 갖는 (200)와 (112)면의 회절 신호들이 관측되었고, 상대적으로 약한 회절 세기를 갖는 (101), (211), (301), (103), (312)와 (420)면의 회절 신호들은 각각 18.6$^{\circ}$, 31.1$^{\circ}$, 40.1$^{\circ}$, 44.6$^{\circ}$, 49.2$^{\circ}$와 57.1$^{\circ}$에서 나타났다(Fig. 1). 이결과를 JCPDS(86-0996)와 비교함으로써, 합성된 형광체 분말의 결정 구조는 정방정계임을 확인할 수 있었다. $Eu^{3+}$의 함량비가 0.05 mol에서 0.15 mol로 증가함에 따라 주 피크인 (200)면의 회절 신호의 세기는 증가한 반면, 0.20 mol에서는 급격하게 감소하였으며, 이 경우에 반치폭의 크기는 0.16$^{\circ}$이었다. 결정 입자의 크기를 결정하기 위하여 (200)면의 회절 피크에 대한 정보를 잘 알려진 Scherrer의 식에 대입하여 계산한 결과, $Eu^{3+}$의 함량비가 0 mol인 경우에, 평균 크기는 48 nm이었다. $Eu^{3+}$ 함량비를 증가함에 따라 결정 입자의 크기도 비례하여 증가하였으며, 0.15 mol에서 최대값을 나타내었으나, 농도 억제 효과로 인하여 0.20 mol 에서는 현저히 감소하였다. 표면 형상의 변화를 관측한 SEM 측정 결과에 의하면, $Eu^{3+}$의 함량비가 0 mol에서 0.15 mol로 증가함에 따라 결정 입자의 모양은 사다리꼴 형태에서 모서리가 둥글게 깎인 구형으로 변형되는 것을 관측할 수 있었으며 평균 크기는 500 nm이었다(Fig. 2). $Eu^{3+}$의 함량이 0.20 mol인 경우에 결정 입자의 형상은 더욱 구형에 접근하였으나, 평균 크기는 최소값을 나타내었다. 실험 결과로부터, 적절한 함량비를 갖는 $Eu^{3+}$ 이온을 첨가함으로써 적색 형광체 $Gd_{1-x}VO_4$ : $Eu^{3+}$ 분말의 결정 크기와 발광 세기를 제어할 수 있음을 제안한다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2008.11a
• /
• pp.197-201
• /
• 2008

Conceptual cost estimates for domestic highway projects have generally been conducted using governmental unit-price references. Inaccuracies in governmental unit-price data has repeatedly addressed in the Korean construction industry which often lead to poor decision making and cost management practices. Thus, needs for developing a better way of conceptual cost estimating has been widely recognized. This research is considered as the first step in developing such model using real-world cost data based on actual construction activities. The data analyzed in this paper includes 41 P.S.C (Prestressed Concrete) Box bridges which broke into 4 categories based on construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). Actual design documents; including actual cost estimating documents, drawings and specifications were carefully reviewed to effectively break down cost structures for PSC girder bridges. Among more than 40 cost categories for each P.S.C girder bridge type, 7 of them were identified which accounted for more than 95% of total construction cost (ILM: 99.47%, MSS: 99.22%, FSM: 98.18%, and FCM: 98.12%). In order to validate the clustering of cost categories, the variation of each cost category has been investigated which resulted in between -1.16 % and 0.59%.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.44 no.4 s.316
• /
• pp.28-35
• /
• 2007

Airbone laser altimeters have been utilized for 3D topographic mapping of the earth, moon, and planets with high resolution and accuracy, which is a rapidly growing remote sensing technique that measures the round-trip time emitted laser pulse to determine the topography. The traveling time from the laser scanner to the Earth's surface and back is directly related to the distance of the sensor to the ground. When there are several objects within the travel path of the laser pulse, the reflected laser pluses are distorted by surface variation within the footprint, generating multiple echoes because each target transforms the emitted pulse. The shapes of the received waveforms also contain important information about surface roughness, slope and reflectivity. Waveform processing algorithms parameterize and model the return signal resulting from the interaction of the transmitted laser pulse with the surface. Each of the multiple targets within the footprint can be identified. Assuming each response is gaussian, returns are modeled as a mixture gaussian distribution. Then, the parameters of the model are estimated by LMS Method or EM algorithm However, each response actually shows the skewness in the right side with the slowly decaying tail. For the application to require more accurate analysis, the tail information is to be quantified by an approach to decompose the tail. One method to handle with this problem is proposed in this study.

• Journal of the Korea Concrete Institute
• /
• v.14 no.3
• /
• pp.291-298
• /
• 2002

Recently, construction of reinforced concrete tall buildings is widely increased according to the improvement of material quality and design technology. Therefore, differential shortenings of columns due to elastic, creep, and shrinkage have been an important issue. But it has been neglected to predict the Inelastic behavior of RC structures even though those deformations make a serious problem on the partition wall, external cladding, duct, etc. In this paper, analysis system for prediction and compensation of the differential column shortenings considering time-dependent deformations and construction sequence is developed using the objected-oriented technique. Developed analysis system considers the construction sequence, especially time-dependent deformation in early days, and is composed of input module, database module, database store module, analysis module, and analysis result generation module. Graphic user interface(GUI) is supported for user's convenience. After performing the analysis, the output results like deflections and member forces according to the time can be observed in the generation module using the graphic diagram, table, and chart supported by the integrated environment.

• Journal of the Korea Convergence Society
• /
• v.8 no.7
• /
• pp.341-348
• /
• 2017

The aim of this study is to distinguish children with high-functioning autism spectrum disorder (ASD) from the norm group by identifying their Intelligence with Korean Wechsler Intelligence Scale for Children-Fourth Edition (K-WISC-IV) profile analysis. The article were administered to 90 children with high-functioning ASD (6-16) years and has surveyed the average of the Full scale IQ, index scores, and subtest scores of K-WISC-IV. Also, this study has conducted a single-subject T-test in order to verify whether Full scale IQ, index scores, subtest scores are different from those of the norm group. The results show that children with high-functioning ASD achieved significantly lower scores on Processing Speed Index, compared to the norm group. Furthermore, their scores in Comprehension, Picture Concept, Picture completion, Coding, and Symbol Search were significantly lower than those of the norm group. It is likely that what have turned out to be the cognitive weaknesses of high-functioning ASD children by K-WISC-IV analysis, including slow process speed, low social judgement, and difficulty in visual stimuli in everyday life are interrelated to their unique characters.

• 한국지구과학회:학술대회논문집
• /
• 2010.04a
• /
• pp.110-110
• /
• 2010

2009년 7월 23일-24일 양일간의 APEC MTF 컨퍼런스는 APEC 회원 경제가 아시아-태평양지역에서 광업부문의 지속가능한 발전의 주제를 토의할 기회를 제공했다. 본 컨퍼런스는 APEC의 광업부문의 지속가능한 발전이라는 프로젝트의 중요 부분이며 컨퍼런스의 활발한 참여는 프로젝트의 성공을 증진시켰다. 지속가능한 발전에 대한 안건이 수년간 APEC의 핵심부분이었으며, 특히 광업장관(MRM)회의에 상정되어 왔다. 2004년 6월 칠레 안토파가스타의 제1차 회의에서, 광업장관들은 APEC 지역에서 광업 및 금속산업의 지속가능한 발전은 부를 창출하고, 환경사업을 창출하며, 사회적으로 책임있는 발전을 도모하며 사회를 위한 향상된 가치를 만들어낸다는데 동의했다. 초기의 action item들 중에서 지속가능한 발전에 있어서 광물 및 금속의 기여를 규명하는 것도 있었다. 광업에 있어서 지속가능한 발전에 대한 안건의 토의는 2005년 10월 한국의 경주 제2차 APEC MRM 회의에서 속계되었다. 관련된 action task는 채광 후 토지운영 뿐만 아니라 에너지 효율기술, 광업 오염 통제 기술과 같은 환경친화적인 채광기술에 대한 정보교환 및 협조를 독려하는 것이었다. 2007년 호주 퍼스의 제3차 회의에서 APEC MRM 회의는 특히 지구화의 시대에 APEC 지역 광물자원의 지속가능한 발전에 대한 긴밀한 지역적 협조에 대한 필요성을 인지하고 있다. 장관들은 역시 광업부문에서 지속가능한 발전에 대한 APEC 위상을 정립하기 위한 작업을 주도하기로 했으며 APEC 경제의 공통관심사를 UNCSD에 반영키 위한 자료제공을 하기로 결정했다. APEC 광업분야의 지속 가능한 개발에 관한 APEC MTF회의는 호주, 캐나다, 칠레, 중국, 인도네시아, 일본, 말레이시아, 파푸아 뉴기니, 페루, 필리핀, 한국, 러시아, 싱가포르, 타이완, 태국, 미국, 베트남에서 자신들의 지속 가능한 개발을 위한 활동에 관한 발표나 의견을 제시하였다. 세계 은행이나 AIM에서도 발표를 하였다. 중요한 소주제들은 다음과 같다. $\cdot$ APEC MTF가 APEC 광업분야의 지속 가능한 발전을 추구하는데 있어 적절한 포럼이라는 것 $\cdot$ 기업들이 사회적 책임(CSR)을 성실히 이행할 필요가 있다는 것 $\cdot$ 수자원과 인적자원의 부족을 다룰 필요가 있다는 것 $\cdot$ 적절한 광산 복구가 필요하다는 것이다. 한국은 "광업분야의 지속가능한 발전을 위한 환경과 광업간의 균형"이라는 프로젝트 아이디어를 제안했다. 인도네시아와 말레이시아는 한국측 프로젝트 수행의 중요성을 강조했다. 러시아 연방은 "광업에 있어 투자 활성화"라는 프로젝트 아이디어를 제안했다. 이 관점에서 MTF는 APEC 투자전문가 그룹과의 협력을 지지했으며 이 포럼간 활동을 활성화시키기 위하여 APEC 사무국에 요청했다. 이 프로젝트는 세계 광업분야의 투자를 증진시키는 최적관행 분석에 따라 제안될 것이고 수행될 것이다. 말레이시아는 광업 및 광업 산업의 지속가능한 발전지시자를 위한 역량구축 프로젝트를 제안했다. 태국은 말레이시아의 제안을 지지했으며 공동프로젝트를 제안했다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.6
• /
• pp.485-492
• /
• 2014

In regards to natural disasters, vulnerability analysis is a component of the disaster risk analysis with one of its objectives as a basis for planning priority setting activities. The volcano eruption raises many casualties and property in the surrounding area, especially when the volcano located in densely populated areas. Volcanic eruptions cannot be prevented, but the risk and vulnerability can be reduced which involve careful planning and preparations that anticipate a future crisis. The social vulnerability as social inequalities with those social factors can influence the susceptibility of various groups to harm and govern their ability to respond. This study carried out the methods of Social Vulnerability Index (SoVI) to measure the socially created vulnerability of the people living in Merapi proximal hamlets in Central Java, Indonesia that refers to the socioeconomic and demographic factors that affect the resilience of communities in order to describe and understand the social burdens of risk. Social vulnerability captured here, using a qualitative survey based-data such as interviews to local people with random ages and background to capture the answer vary, also interviews to stakeholders to help define social vulnerability variables. The paper concludes that by constructing the vulnerability index for the hamlets, the study reveals information about the distribution and causes of social vulnerability. The analysis using SoVI confirms that this method works well in ensuring that positive values indicating high social vulnerability and vice versa.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.1
• /
• pp.135-145
• /
• 2020

This research is mainly aimed at finding out about the effects of the safety and health management system on corporate performance through systematic operation by efficiently allocating material and human resources within the company by participating all employees and stakeholders in order to prevent and maintain industrial accidents and the optimal working environment, and how to maintain and activate the safety and health management system at the center of electric contractors.The analysis results are as follows. First, management, organizational management and resource preparation will have a positive impact on the management capability of the electric power corporation. It was assessed that the more well-transmitted and understood within the organization, the better the construction plan, the better the equipment management status, the more positively the management capability of electric works was to be achieved. Second, management, organizational management and resource preparation will have a positive impact on corporate management performance.This seems to have a positive effect on a company's business performance when the standards of OHSAS are met with construction plan and construction equipment management are high as related information such as industrial safety and health laws are strengthened and companies' safety and health activities, advanced safety and culture are released to facilitate organizational management.Third, the management ability of the electric power corporation will have a mediated effect on the effect of management, organization management and resource preparation on the performance of the enterprise. This means that the direct effect of the independent variable management organization on corporate management performance is .401 The indirect effect is .168.658 shows that the direct effect of resource preparation on corporate management performance is .423, the indirect effect is .178 and the total effect.It was analyzed at 643.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.9 no.4
• /
• pp.145-152
• /
• 2009

Domestic Kori-1 MCR was partially modified in 2007 and will be renovated entirely in 2013. Digital devices partially replacing original analog devices have been introduced and standard alone computer systems such as SPDS have been integrated into the plant computer. Upgrading KSNP's MCR based on the ditalization is planned for 2015. However, the site engineers and operators are reluctant to the advanced systems. Therefore, a prototype for the KSNP's advanced MCR has been developed to increase the acceptance level of the operators and field engineers and also, to evaluate user interfaces and I&C architecture. For enhancing support of the operators' work, a P&ID based display system composed of multi-layers, which are linked through a context sensitive menu each other, has been adopted. The $1^{st}$ layer displays a simplified P&ID, the $2^{nd}$ layer control related diagrams such as controllers and logic diagrams, the $3^{rd}$ layer trends, etc. The end point view of MCR for KSNP is also suggested considering reliability and operability of the digital systems. Additionally, modernization strategies over the overhaul periods, that do not have much impact on operation and configuration efforts are suggested.

• The Journal of Small Business Innovation
• /
• v.20 no.1
• /
• pp.47-57
• /
• 2017

Closing the book for the recent accounting period and issuing financial statements is one of the most common challenges for companies. This study examines a case of an automated financial close process and discusses issues related to its implementation. First, the study introduces the closing process of a case company including the purpose, improvement plan, and designing process. Second, the study discusses the impacts of the newly adopted system. Specifically, it reveals that under the new plan, close process automation has been maximized. It also shows that raw data validation has been improved so that past data errors can be categorized by their types and removed before the closing process begins. The order of the process has also been redefined saving closing time. Third and finally, difficulties and considerations for successful use of the system have been discussed. This study aims to provide useful information to companies which consider implementing more organized closing systems. We expect that this study will be helpful to small and medium enterprises which suffer from delayed closing but have little experience with automated BPM system.