• Korean journal of applied entomology
• /
• v.36 no.1
• /
• pp.43-47
• /
• 1997

This study was carried out in the laboratory to clarify effects of different temperature of Protopulvinaria mangiferae(Green) on development, survivorship and reproduction. Developmental period of the mango shieldscale from crawlers to preoviposition adult decreased as temperature increased. The threshold temperature andthermal constants for the development of one generation were 11.7"C and 1000.0 day-degrees, respectively. At25$^{\circ}$C and 30$^{\circ}$C, survival rate from egg to preoviposition adult were 82% and 6096, respectively. Hatchability ofeggs was more than 99% at both condition. The reproductive period overaged 50 days(2SnC) and 33 days(30$^{\circ}$C). After mature adult began to reporduce, and more than 50% of the crawlers emerged during the firsthalf of their life time. The net reproduction rate per generation(R), mean length of a generation0 and intrinsicrate of natural increase(r, ) were higher at 25$^{\circ}$C than at 30"C, and the values measured at 25$^{\circ}$C were 132.6, 76.2 and 0.064/female/day, respectively.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2018.05a
• /
• pp.37-40
• /
• 2018

빅데이터 산업 부상과 함께 교육 데이터 분석 분야가 새롭게 주목받고 있다. 교육 현장에서 학습 데이터의 양과 종류는 꾸준히 증가하고 있고 이를 분석하기 위한 정보기술도 계속 발전하고 있다. 한편, 학교 교육은 사회적 성취와 밀접한 관련이 있어 사회이동의 중요한 수단이 되는 만큼 학교 교육으로부터 이탈할 위험이 있는 학생들을 조기에 발견하여 이탈을 방지하는 것은 매우 중요하다. 본 논문은 대학생의 중도탈락을 예방하기 위해 로지스틱 회귀분석과 다층 퍼셉트론 기법을 이용해 학습 데이터를 분석하여 예측 모델을 생성하고 해당 모델을 평가한다. 평가 결과, 다층 퍼셉트론 모델이 로지스틱 회귀분석 모델에 비해 정확도와 재현율은 우수하였지만 정밀도는 약간 저조하였다.

• Journal of Industrial Convergence
• /
• v.6 no.1
• /
• pp.35-56
• /
• 2008

포화상태인 인증사장은 신규기업 유치 보다 기존기업 유지를 통해 이탈율을 최소한으로 줄여야 한다. 기업의 여건, 성향, 요구사항 등을 분석하여, 고객관리시스템을 도입하여야 한다. 수많은 기업정보를 세분화하여 분류하고 이것을 이용하여 고객정보를 관리해야 한다. CRM은 고객관리를 효율적으로 할 수 있는 정보관리시스템이다. CRM 시스템을 효과적인 구축을 위해서는 설문지 및 QFD을 통해서 고객의 요구사항을 파악하고, SWOT을 통해 외부환경 및 내부역량을 파악한다. 또한, 내부적으로 CRM 체크리스트를 작성하고, 체크리스트에 기록된 내용을 분석하여 나온 결과를 중심으로 하여 부족한 부분에 대해서는 집중적으로 개선방안을 수립해야 한다. 고객의 등급을 RFM에 의해 분류하여 관리해야 한다. 고객의 등급 및 분류에 따라 마케팅 전략을 수립하여 운영 및 관리를 해야 한다. CRM 구축을 통해 CRM 인프라를 강화하고 CRM 전략을 수립해야 마케팅 및 기술 경쟁력을 확보할 수 있을 것이다.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.1
• /
• pp.261-268
• /
• 2013

In this paper, we propose the algorithm that improves the linearity of the walking assistant robot on lateral slopes. The walking assistant robot goes out of the course due to the rotational moment which is caused by the weight of the robot and the slope. To compensate this, we give the weight to each driving axle after comparing the real rotational angular velocity with the target rotational angular velocity which is entered by an user. The results of applying the algorithm to the real walking assistant robot show that the yaw axis deviation of the robot without the algorithm diverges, but the yaw axis deviation of the robot with the algorithm lies within 20cm, which can be recognized as stable. In addition, the changing rate of the course deviation is stabilized and shows no more course deviation, after moving 300cm.

• Geotechnical Engineering
• /
• v.13 no.5
• /
• pp.155-168
• /
• 1997

The phenomena of detachment and movement of One particles are one of the important mechanisms both in geotechnical and geoenvironmental engineering. In geoenvironmental engineering, in particular, movement of fine particles may facilitate the transport of contaminants since the particle surfaces absorb contaminants before movement. Weathered granitic residual soils, which are the most abundant in Korea. contain large quantities of fine particles up to 50%. The characteristics of fine particle movement of weathered granitic residual soils are investigated in this paper. Samples are obtained from Poiiong, Shinnaedong in Seoul and Andong in Kyungpook : each of the samples represents typical residual soil types in Korea. Laboratory experiments for the three adopted soil types are performed. It is found that effluent concentration of the samples is influenced by porosity, fine particle percentage and particle size distribution. The critical velocity decreases as the fine particle percentage increases and the rate of change of erosion rate increases as the porosity increases. And well-graded samples showed less effluent concentrations compared to poorly-graded samples. The governing equation on the physical mechanism of fine particle movement and its nomerical solution scheme are suggested on the basis of the test results.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.8 no.3
• /
• pp.187-196
• /
• 2014

This paper suggests linearity enhancement algorithm to Ensure safety of Mobile Walker on Slope. Mobile Walker happens to get off track due to external forces from Walker's weight and the degree of the slope while slope driving. In order to compensate this, this research used the controller that estimates the external forces according to the slope of road surface and adjusts it to the motor output. Also, through comparisons between targeted rotational angular velocity which the user inputs and its velocity of the robot, algorithm was applied which applies a weight to each shaft. As a result of applying the proposed correction controller, it diverges in case of non-compensation experiments that deviates when moving, but it case of applying the ramp calibration algorithm, the deviation distance at max was within 10cm that it keeps safe driving, and change rate of deviation distance was also stabilized after 1m where no more changes occurred.

• Nuclear Engineering and Technology
• /
• v.27 no.6
• /
• pp.877-887
• /
• 1995

YGN 3 is the first nuclear power plant to use the Core Protection Calculator (CPC) as the core protection system and the Core Operating Limit Supervisory System (COLSS) as the core monitor-ing system in Korea. The CPC is designed to provide on-line calculations of Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD) and to initiate reactor trip if the core conditions exceed the DNBR or LPD design limit. The COLSS is designed to assist the operator in implementing the Limiting Conditions for Operation (LCOs) in Technical Specifications for DNBR/Linear Heat Rate (LHR) margin, azimuthal tilt, and axial shape index and to provide alarm when the LCOs are reached. During YGN 3 initial startup testing, extensive CPC/COLSS related tests ore peformed to ver-ify the CPC/COLSS performance and to obtain optimum CPC/COLSS calibration constants at var, -ious core conditions. Most of test results met their specific acceptance criteria. In the case of missing the acceptance criteria, the test results ore analyzed, evaluated, and justified. Through the analysis and evaluation of each of the CPC/COLSS related test results, it can be concluded that the CPC/COLSS are successfully Implemented as designed at YGN 3.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05b
• /
• pp.543-548
• /
• 1996

이 연구의 목적은 고리 3/4호기 및 영광 1/2호기의 음의 중성자속 변화율에 의한 원자로 트립(NFRT) 설정치를 제거하여 불의의 제어봉 낙하 사고시에 원자로 트립을 방지하는 것이다. 현재의 인허가된 안전해석 방법론에 의하면 제어봉 낙하사고시에 NFRT에 의하여 원자로가 트립되고 결국 발전소의 이용율이 감소하게 되는데 본 연구에서 적용된 새로운 방법론으로는 이 NFRT 보호신호 없이도 제어봉 낙하사고시에 발전소의 안전성을 입증할 수 있다. 안전분석은 주기별로 다른 핵설계 자료 즉, 냉각재 온도상수, 전출력에서의 제어봉가 및 제어봉 삽입한계 등을 이용하여 수행되었다. 웨스팅하우스형 연료인 OFA 및 V5H에 대하여 고리 4호기 6주기외 3개 주기에 대하여 분석되었다. 분석된 주기들에 대해서 NFRT 신호 없이도 핵비등 이탈률(DNBR) 설계기준을 모두 만족하였다. 그러므로 고리 3/4호기 및 영광 1/2호기의 NFRT 신호는 제거할수 있고 이로써 제어봉 낙하사고시의 발전소 불시정지를 방지할수 있다.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.32 no.4
• /
• pp.189-212
• /
• 2021

The purpose of this study is to analyze an usage behavior for the public library website through web traffic. For this purpose, using Google Analytics and growth hacking technique, the data of A public library website log was analyzed for three months from August 1, 2021 to October 31, 2021. As a result of the study, the young age group of 18-24 years old and 25-34 years old recorded a high rate of new member registration, & it was found that the inflow rate through SNS was high for external inflows. As a result of analysis for the access rate by time, it was found that the time with the highest inflow rate was between 10 am and 11 am both on Wednesday and Friday. As a access channel, the access rate using mobile (64.90%) was quite high, but at the same time, the bounce rate (27.20%) was higher than the average (24.93%), & the rate of duration time (4 minutes 33 seconds) was lower than thee average (5 minutes 22 seconds). Finally, it was found that the utilization rate of reading program events and online book curation service, which the library focuses on producing and promoting, is very low. These research results can be used as basic data for future improvement of public library websites.

• Communications of Mathematical Education
• /
• v.19 no.1 s.21
• /
• pp.25-32
• /
• 2005

현재 한국의 많은 대학의 수학과는 낮은 지원율 신입생 미충원 그리고 전과/편입학/자퇴 등 높은 이탈 등으로 학생자원 부족에서 오는 생존이 위협되는 위기에 처해있다. 실제로 몇 년 사이에 학생 모집이 중단됨으로서 폐과가 진행 중인 대학의 수학과가 나타나고 있다. 한국의 대학교육에서 수학과가 퇴조하는 이러한 현재 상황의 진행이 3-5년 후 대학 및 대학원의 수학전공은 어떤 상황에 있을 것인가? 학생자원 감소라는 현재의 추세가 계속 진행된다면, 대학의 학문 체계와 대학교육에서 수학의 위치 역할은 무엇을 의미하는가? 이러한 대학의 수학전공에 지원하는 학생자원 부족 문제는 진지하게 구체적으로 다루고 도전하고 해결 방안을 구해야 할 문제인가? 아니면 일시적인 퇴조 현상에 대한 기우인가?