• 호남수학학술지
• /
• 제33권2호
• /
• pp.279-300
• /
• 2011

For a subset system M on any poset, M-Scott notions, such as M-way below relation,M-continuity,M-Scott convergence (of nets and filters respectively) and M-Scott topology are proposed Any approximating auxiliary relation on a poset can be represented by an M-way below relation such that this poset is M-continuous. It is shown that a poset is M-continuous iff the M-Scott topology is completely distributive. The topology induced by the M-Scott convergence coincides with the M-Scott topology. If the M-way below relation satisfies the property of interpolation then a poset is M-continuous if and only if the M-Scott convergence coincides with the M-Scott topological convergence. Also, M-continuity is characterized by a certain Galois connection.

• 대한공업교육학회지
• /
• 제30권2호
• /
• pp.3-11
• /
• 2005

The purpose of this study is to measure the level of the key competencies of industrial high school students and to use it as the basic material so as to improve the key competencies. The subject was 359 industrial high school students(boys: 244, girls: 115) in Seoul, Daejeon, Gwangju, and Busan. The instrument used to measure the key competencies is that developed by Cheol-Young Jeong, which was partly revised with the help of a group of experts. The results of this study showed some of skills were below an average of 3.0, which were writting skill(M=2.85) and speaking skill(M=2.96) in communication skills, logical thinking(M=2.98) in problem solving skills, leadership skill(M=2.88) in interpersonal skills, and self-improvement skill(M=2.96) and the spirit of public service(M=2.93) in self-management and self-improvement skills. But technology skills were above an average of 3.0. And it appeared that technology skills(P=.023) depended on having a certificate or not, and so did communication skills(P=.020) and problem solving skills(P=.034) on the types of a course(employment or entrance into a college). So, to strengthen the key competencies which appeared below an average of 3.0 in this study, not only does the curriculum of industrial high schools need to be reorganized, but systematic strengthening program of key competencies should also be developed.

• 환경생물
• /
• 제37권4호
• /
• pp.579-584
• /
• 2019

독수리 11개체에 GPS를 부착하여 비행특성을 분석하였다. 한국에 월동기간은 평균 131일(SD=17.4)이었고, 평균 비상 비율은 19.6%이었다. 비행고도는 100 m 이하가 21.6%이었으며, 101~200 m는 25.3%, 201~300 m는 19.0%로, 300 m 이하가 65.9%이었다. 시간대별 비상률과 고도는 양의 상관관계(r=0.929)를 보였고, 월별 비행고도 비율은 대부분 101~200 m에 가장 많은 비율을 나타냈다(p<0.05). 월동기 독수리는 비행비율을 낮추고 300 m 이하 고도에서 비행하였다. 독수리의 넓은 행동권, 높은 비행비율, 높은 고도 비행특성은 사회적 상호작용에 의해먹이를 찾는 효율적인 비행방법으로 판단된다.

• Journal of Korean Vacuum Science & Technology
• /
• 제3권1호
• /
• pp.74-78
• /
• 1999

For a high efficient field emission display (FED), the specific vacuum conditions below 10-7 Torr should be required. However, because the FED has the geometrical restriction due to its micro size, the thin film getters can be proposed for chemical pumping as a way to reduce impurity gases in the panel. The thin film getters, developed by employing the coating of new materials such as NI or Pt on getter surface, can be used without any activation process and show the enhanced sorption characteristics. Especially, using the Zr (1${\mu}{\textrm}{m}$) thin film getters with the Pt surface layer, the significant gettering for various active gases could be achieved from 9$\times$10-5 Torr to 1$\times$10-6 Torr or below. this good sorption properties is mainly contributed to the surface coating layer which shows the catalytic effect for gas dissociation and protects the getter materials against oxidation.

• 한국산학기술학회논문지
• /
• 제11권4호
• /
• pp.1248-1253
• /
• 2010

본 논문은 SDS-TWR(Symmetric Double-Sided Two-Way Ranging)의 Ranging 오차를 보정하기 위하여 균등거리비율 개념을 적용한 위치인식 보정 알고리즘인 AEDR(Algorithm for localization using the concept of Equivalent Distance Rate)을 제안하고, 위치인식 실험을 통해 위치인식 측정 성능을 분석하였다. SDS-TWR의 Ranging 오차는 실험에 의하면 비콘노드와 이동노드의 특정 거리구간에서 평균 1m~8m로 측정되었다. 그러나 제안한 AEDR에 의한 위치인식 성능은 실험을 통해 전체적으로 교내 강당과 복도 모두에서 SDS-TWR 보다 4배 정도 우수하였으며, 측정된 3~10m 이상의 위치인식 오차를 평균 2m 내외로, 3m 이내의 위치인식 오차를 평균 1m 내외로 각각 감소시킬 수 있음을 확인하였다. 특히 AEDR은 LOS(Line Of Sight) 보다 NLOS(Non Line Of Sight)에서 훨씬 더 위치인식 보정 성능이 우수함을 나타내며, 대부분의 센서 네트워크의 환경이 NLOS임을 고려할 때 AEDR이 실제환경에서의 위치인식에 큰 도움을 줄 수 있다고 판단된다.

• 설비공학논문집
• /
• 제19권5호
• /
• pp.386-393
• /
• 2007

This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of $120m^3$, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.

• 한국산학기술학회논문지
• /
• 제11권3호
• /
• pp.914-919
• /
• 2010

CSS(Chirp Spread Spectrum)기반에서 SDS-TWR(Symmetric Double Side-Two-Way Ranging)의 거리측정 정확도는 실험에 의하면 전파환경 간섭으로 인해 일부 레인징 구간에서 매우 큰 오차가 발생함을 확인하였다. 본 논문에서는 이러한 문제를 해결하기 위해 레인징 오차를 감소시킬 수 있는 측정거리의 오차비율 오프셋을 적용한 SDS-TWR의 보정 알고리즘($CA_d$)을 제안하였다. $CA_d$는 두 노드를 LOS(Line Of Sight)환경에서 1~25m까지 1m 간격으로 SDS-TWR으로 거리 값을 측정하여, 거리보정에 필요한 각 파라미터의 값을 계산한 후 이를 사용하여 거리값을 보정한다. 제안한 보정 알고리즘의 성능분석 결과, $CA_d$는 SDS-TWR에 비해 오차가 평균 95cm, 최대 오차가 526cm 감소하였고, 는 25m에서 약 60cm의 오차가 발생함을 확인하였다. 이러한 결과를 볼 때 제안한 $CA_d$는 LOS 환경에서 SDS-TWR에 비해 매우 정밀한 정확도를 가진 것으로 판단된다.

• 설비공학논문집
• /
• 제9권3호
• /
• pp.323-332
• /
• 1997

It was reported by some researchers that two-stage parallel-plate ESPs, commonly called electronic air cleaners, show decreasing behavior of collection efficiency as particle size decreases below about $0.03{\mu}m$. This phenomenon is attributed to partial particle charging characteristics, where some of incoming particles are not charged in the charging cell of 2-stage parallel-plate ESP. One way to improve the decreasing collection efficieny in that particle size range is to enforce particle charging quantity in the charging cell. In the present study, in order to do this a 2-wire series-type charging cell modified from a 1-wire normal-type one was suggested and investigated theoretically and experimentally concerning improvement of the collection efficiency. It was confirmed from the experimental and theoretical works that the collection efficiency was apparently improved.

• 한국가스학회지
• /
• 제23권1호
• /
• pp.41-46
• /
• 2019

LNG는 주된 기화기인 해수를 이용하는 해수식 기화기를 이용하여 가스 상태로 소비자에 공급되고 있다. 그러나 겨울철 해수 온도가 $5^{\circ}C$이하로 저하되면 수중 연소식 기화기를 사용하게 되며 이 때 막대한 LNG 기화 소요 비용이 발생하게 된다. 이를 절감하기 위하여 현재의 해수식 기화기의 1단 해수공급을 2단으로 공급하는 공정을 고안하여 그 효과를 분석하였다. 해석 결과, 6m 전열관의 외부에 해수를 2단으로 3m씩 가열할 때 온도가 $1.8^{\circ}C$가 저하되어 해수 온도 $2.5^{\circ}C$까지도 LNG의 기화온도를 $0^{\circ}C$이상으로 배출할 수 있는 것으로 해석되었다. 인천 생산기지에 이 공정이 적용된다면 연간 동계 운전비용 절감량은 LNG 11,770 Ton, 절감액은 117.6억 원으로 분석되었다. LNG를 전량 수입하는 국내 여건에서는 해수 2단 공급 공정을 적용한다면 막대한 에너지와 비용을 절감할 수 있는 매우 효과적인 공정이 될 수 있음을 알 수 있다.

• 한국학교보건학회지
• /
• 제9권2호
• /
• pp.161-170
• /
• 1996

This research was performed to screen eye health status for pre-school children (4~5 age) and establish as eye health checking system m community health center. This data was collected from 1st February, 1995 to 31st October, 1995. To screen the state of their vision, the Developed Visuual Test (D.V.T) was used for pre-school children. This is used at home by their parents and then it is also used among the kindergarten health team at Jung-gu health center in Seoul. This was done with the and of Randot and Han Choun Souk tests. The total number of children who were tested was 1441. Among the children, children aged 5 were 707, and those aged 4 were 734. The results of this study were as follows; * Description of the health status for the pre-school children. 1. The rate of children average vision in both eyes, whose was below 05 by Han Choun Souk are 7.6% (age 4) and 4.8% (age 5). 2. Only 20 4% (age 5) and 30 8% (age 4) of the pre-school children had been tested through the ophthalmic department. 3. The children with a level below 05 (Han Choun Souk test) had been tested only 43% (age 4), and 12% (age 5) 4. There was no particular difficulty in understanding the D.Y.T: 13.9% (age 4), 11.6% (age 5) of the tested children had eye problems. 5. 231 cases were trichiasis, entropin, strabismus, and amblyopia. * The different visual tests. The results of the visual tests between the two groups (parents and health teams) are similar and it shows that parents can easily test at home. * Delivery system of the D.V.T questionnaire The way children's parents received the D.V.T questionnaire were carried out by two ways By mall from the community health center. Send through the institution, for example the kindergarten school The receipt rate of this D.V.T questionnaire sent through the institution was higher than sent by mall.