• Proceedings of the KIPE Conference
• /
• 2015.11a
• /
• pp.139-140
• /
• 2015

본 논문에서는 73kW IPMSM으로 구동되는 직렬 하이브리드 전기자동차 구동시스템에서 직류 전압의 운영 수준에 따른 전력변환시스템의 효율을 분석하였다. 여러 직류 전압 수준에 대한 배터리, 커패시터 및 3상 인버터의 손실을 PSIM을 이용한 시뮬레이션을 통해 분석하여 효율을 알아보았다. 직류 동작 전압을 증가시키면 배터리와 커패시터에서의 손실은 감소하지만, 인버터의 손실은 도통 손실과 스위칭 손실의 변동정도에 따라 달라진다. 분석 결과로 $300V_{dc}$에서 $600V_{dc}$로 직류 전압 운영 수준을 증가시키는 경우에 전력변환시스템의 효율은 증가하는 것을 확인하였다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.47-47
• /
• 2021

글로벌 물산업의 규모는 2019년 기준 약 1,000조원 수준으로 2024년까지 연평균 3.5%의 성장률을 달성할 것으로 예측하고 있다. 특히 코로나 19의 영향으로 디지털 물산업에 대한 투자가 증가하고 있으며 4차산업혁명 등으로 지속 성장이 예상되고 있다. 이러한 디지털 물산업 시장의 성장은 물산업분야의 기술경쟁력의 중요도가 더욱 높아질 것을 예상하게 한다. 우리나라의 물산업에 있어서 기술경쟁력 분석을 위해 많은 연구가 진행되어왔으나 대부분 설문조사에 근거한 정석적 분석에 의존하여 왔다. 정성적인 분석에 의존한 연구의 경우, 대상 응답자들이 특정 분야에 치중되어 분석되거나 긍정적으로 판단하는 경향이 있어 우리나라의 물산업 기술의 현재 상황을 과대평가할 가능성이 있다. 또한 연구시점, 설문분야에 따라 결과가 상이할 수 있어 결과의 신뢰성 및 시계열적 추이분석이 어려워 물산업정책 수립을 위해 활용되는데 한계가 존재하였다. 본연구에서는 기존의 정성적 분석에서 벗어나 정량적인 자료에 근거하여 우리나라의 물산업 기술수준과 시장지배를 동시에 고려하여 분석하였다. 물산업의 기술영향력지수(Cites per Patent)와 시장지배력지수(Patent Family Size)를 기준으로 선도국가와 국내 물산업 기술수준 및 시장영향력을 비교하고 평가하였다. 연구결과의 정책적 활용을 위해 물기술과 물시장의 상이한 분류체계를 물시장 중심으로 재분류하여 물산업 기술경쟁력을 분석하여 제시하였다. 연구결과 우리나라의 국내 기술영향력 중 가장 낮은 분야는 하수도 디지털 분야로 선도국가 대비 30% 수준이었으며 시장지배력분야 또한 하수분야로 7% 수준으로 파악되었다.

• Journal of the Korean Society for information Management
• /
• v.35 no.1
• /
• pp.103-127
• /
• 2018

This study examined differences in job stresses, depression and state anxiety levels relating to sociological characteristics of records managers and studying whether the mediating effect of state anxiety levels significantly occurs on the depression followed by their job stresses. So we distributed questionnaires of 9 factors including sociological characteristics to record managers, asking them job stresses, depression, and state anxiety levels, and collected 98 questionnaires finally. We analyzed the effect of mediation on the surveyed data using Regression Analysis. As a result, it was found that there is a full mediating effect of state anxiety level between job stress and depression, and that, therefore, state anxiety levels of the record managers must be managed to lower their depression levels.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.12
• /
• pp.57-64
• /
• 2008

In this paper, we propose a system-level simulator for the performance analysis of a Solid-State Disk (SSD) in PC environment by using TLM (Transaction Level Modeling) method. Our method provides quantitative analysis for a variety of architectural choices of PC system as well as SSD. Also, it drastically reduces the analysis time compared to the conventional RTL (Register Transfer Level) modeling method. To show the effectiveness of the proposed simulator, we performed several explorations of PC architecture as well as SSD. More specifically, we measured the performance impact of the hit rate of a cache buffer which temporarily stores the data from PC. Also, we analyzed the performance variation of SSD for various NAND Flash memories which show different response time with our simulator. These experimental results show that our simulator can be effectively utilized for the architecture exploration of SSD as well as PC.

• Convergence Security Journal
• /
• v.22 no.5
• /
• pp.81-87
• /
• 2022

The purpose of this paper is to take a look the effect of the physical security level of companies possessing national core technology on security performance and work efficiency. To this end, a survey was set out for about 200 security officers for a month. In the survey, the independent variable was physical security level, the parameter was security performance, and the dependent variable was work efficiency. Reliability analysis, validity analysis, discriminant validity analysis, etc. were analyzed for causality through SPSS. As a result, "Physical Security Level ⇒ Security Performance, Security Performance ⇒ Work Efficiency" was adopted, but "Physical Security Level ⇒ Work Efficiency" was rejected. Therefore, it was found that the physical security level affects work efficiency through security performance, which is a parameter. However, it was found that the physical security level did not directly affect work efficiency. In order to improve work efficiency in the future, improving security performance should be a priority.

• Journal of the Korean Chemical Society
• /
• v.57 no.5
• /
• pp.640-655
• /
• 2013

The purpose of this study is to analyze the cognitive demands level of the description about 'changes of state' and 'kinetic theory' on the 'science 1' textbooks by the 2007 revised curriculum. The three types of curriculum analysis taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science 1' textbooks. The most higher level of cognitive demands about the concepts have been discussed here due to the focus of the concepts. The first, the cognitive demand level about 'three states of substances' depending on the motion of their particles in 6 textbooks is a early formal operational stage because of using by the application of kinetic theory. The second, the cognitive demand level about 'diffusion' and 'evaporation' is a early formal operational stage, because the particles move around faster so they can change their position. The third, the cognitive level of the pressure and volume in a gas is a early formal operational stage because of explaining only phenomena in simple correspondence with formal model of kinetic theory. And simple functional relationships beyond linear on the graph of the volume and pressure of gas, the volume and temperature of gas is also a early formal operational stage. The fourth, the cognitive level of the energy of heat by a change of the state is also a early formal operational stage because kinetic theory picture accepted as providing explanation by the change of the state. And functional relationships beyond linear on the graph of the explanation of boiling point of water in water is also a early formal operational stage.

• Journal of the Korean Chemical Society
• /
• v.65 no.1
• /
• pp.37-47
• /
• 2021

In this study, the model cognition level of high school science-gifted students about the two types of acid-base models taught in secondary schools was analyzed. In order to find out the model cognition level of students, 12 items were developed based on the acid-base reaction and the dissociation reaction of acids and bases. The subjects of the study were 95 students of two science-gifted schools. As a result of the questionnaire analysis, model cognition levels were analyzed 6 levels in the context of consistency, inconsistency, and unexplainable scope of the two models. In the acid-base reaction item, the largest percentage of students cognized only understanding of the two models. In the acid-base dissociation reaction item, they understood the two models and perceived the 'Known Ignorance' that cognizes the limitations of one model. However, there was only one student who perceived the limitations of both models and all of the 'Unknown Ignorance' that the model could not explain. Through this, we argued that there is a need for educational efforts to raise the model cognition level of science-gifted students.

• International Journal of Highway Engineering
• /
• v.10 no.4
• /
• pp.65-77
• /
• 2008

LOS(Level of Service) concept are popularly used in many countries as the MOEs to evaluate the road construction and operation plans. However, MOEs such as travel time and delay only measure quantitative factors describing traffic flow, although qualitative factors such as scenic, comfort and reliable factors are very important for roadway drivers to define the LOS. Therefore, this paper are focusing on verifying the difference between perceived LOS and LOS in KHCM, and proving qualitative factors affecting Drivers' Perceived LOS in Urban Arterial. As a result, following outputs are obtained; (1) verifying the difference between perceived LOS(PLOS) and LOS in KHCM (2) proving that qualitative factors such as scenic and driver behavior factors affects PLOS (3) suggesting that qualitative factors should be considered in MOEs of LOS

• Electronics and Telecommunications Trends
• /
• v.20 no.2 s.92
• /
• pp.115-127
• /
• 2005

본 고에서는 국내 인터넷전화서비스의 사업환경을 살펴보고 향후 시장을 전망하였다. 사업환경 분석은 시장, 사업자 그리고 정책환경 측면에서 분석을 실시한다. 시장 분석에서는 인터넷전화의 가입의향과 PSTN 해지의향, 인터넷전화서비스 선호 고객의 특성 등을 조사 분석하였다. 사업자 분석에서는 현재 인터넷전화서비스를 제공하고 있거나 향후 제공할 예정인 사업자들을 대상으로 이들이 추구할 전략 방향을 분석하고 이로부터 유사한 전략을 추구할 전략집단을 도출하였다. 정책환경은 그간의 인터넷전화의 정책동향과 정책 이슈를 중심으로 분석하였다. 시장전망은 가정용과 기업용을 구분하여 실시하며, 가정용은 다시 시내번호 인터넷전화와 070 인터넷전화를 구분하여 시장을 전망하였다. 기업용은 기업의 규모에 따라 인터넷전화 이용형태가 상이한 점을 반영하여 시장 전망을 실시하였다. 그 결과, 가정용 인터넷전화의 포화수준은 시내번호 인터넷전화가 155만 회선, 070 인터넷전화가 약 382만 회선으로 추정되었으며 기업용 070 인터넷전화의 포화수준은 약 130만 회선으로 추정되었다. 그 과정에서 시내번호 인터넷전화의 새로운 요금수준에 대한 고객의 수용도, 상호접속의 정비 시점이 인터넷전화 확산에 큰 영향을 미치는 요인임을 발견할 수 있었다.

• The Journal of Society for e-Business Studies
• /
• v.16 no.3
• /
• pp.129-143
• /
• 2011

In modern industrial society, the importance of inter enterprise collaboration is more emphasizing for the survival of companies and strengthening its competitiveness. The studies using IT systems effect on inter-enterprise collaboration are already taken several times. However, there is not much systematic research to evaluate the informatization level of B2B collaboration. In this paper, we examined the level of B2B collaboration and the use of IT systems for each business area in small and medium-sized collaborative enterprise which are classified into shipbuilding, automobile, and electronic industry. We verified that the level of collaboration between companies are significant to the level of IT use for each business area by regression analysis. The conclusion of this study is that the level of B2B collaboration and the use of IT systems for each business area are different.