• 한국분말재료학회지
• /
• 제6권1호
• /
• pp.18-35
• /
• 1999

Phase equilibria in the system Si3N4-TiC-TiCxN1-x-C-N were determined by thermodynamic calculations (CALPHAD-method). The reaction peaction paths for Si3N4-TiC and SiC-TiC composites in the Ti-Si-C-n system were simulated at I bar N2-pressure and varying terpreatures. At a temperature of 1923 K two tie-triangles (TiC0.34N0.66+SiC+C and TiC0.13N0.87+SiC+Si3N4) and two 2-phase fieds (TiCxN1-x+SiC; 0.13

• 한국세라믹학회지
• /
• 제24권1호
• /
• pp.23-32
• /
• 1987

Synthesis of high purity ultrafine Si3N4 and ${\beta}$-Sialon powders was investigated via the simultaneous reduction and nitriding of amorphous SiO2, SiO2-Al2O3 system prepaerd by hydrolysis of alkoxides, using carbonablack as a reducing agent. In Si(OC2H5)4-C2H5 OH-H2 O-NH4OH system, hydrolysis rate increased with increasing reaction temperature and pH. Pure ${\alpha}$-Si3N4 was formed at 1350$^{\circ}C$ for 5 hrs in N2 atmosphere. In Si(OC2H5)4-Al(OC3H7)3-C6H6-H2 O-NH4OH system, weight loss increased as Si/Al ratio decreased. Single phase ${\beta}$-Sialon consisted of Si/Al=2 was formed at 1350$^{\circ}C$ in N2 and minor phases of ${\alpha}$-Si3N4, AIN, and X-phase were existed besides theSialon phase at other Si/Al ratios. The Si3N4 and Sialon powders synthesized from alkoxides consisted of uniform find particles of 0.05-0.2$\mu\textrm{m}$ in diameter, respectively.

• 한국정보통신학회논문지
• /
• 제25권6호
• /
• pp.757-765
• /
• 2021

2018년 미 국방부 국가안보전략에 포함된 다영역작전 수행을 위해서는 C4I 체계 간의 적시적인 데이터 공유가 선행되어야 가능하다는 것을 인식하고 문제 해결을 위해 노력하고 있다. 한국군도 수 차례 연구를 통해 C4I 체계간 데이터 연동과 표준화에 대한 문제가 제기 되었고, 이를 해결하기 위한 새로운 방안의 수립이 필요한 상황이다. 본 연구에서는 미국방성이 2003년 데이터 전략 수립 후 이를 구현하기 위해 약 20여 년간 추진해온 사례 분석을 통해 문제 해결 방안을 도출하고, 한국군 C4I체계 운용환경에 적합한 데이터 전략 수립, 데이터 모델 개발, 데이터 공유를 위한 표준 선정, 그리고 공유 데이터 개발 절차를 제안함으로써, 한국군 C4I체계간 데이터 공유 능력을 향상시키고자 한다.

• Journal of the Optical Society of Korea
• /
• 제13권4호
• /
• pp.464-467
• /
• 2009

The grating projection method with phase-shifting technique is very useful in measuring the 3-dimensional (3D) shape with high accuracy and speed. In this work, we have developed an ultra high-speed digital laser grating projection system using a high-power laser diode and a highsensitivity CMOS camera. With our system, the optical measurement required to find out the profile of a 3D object could be carried out within 2.6 ms, which is a significant ($\sim$10 times) improvement compared with those of the previous studies.

• 융합보안논문지
• /
• 제12권4호
• /
• pp.57-69
• /
• 2012

C4ISR 체계는 군사작전 지휘통제를 위한 중요 수단이다. 그러므로, 지휘통제체계의 마비를 위한 각종 변형된 사이버테러 시도에 노출되기 쉽다. 일반적인 정보체계는 IDS와 방화벽을 주요 정보보호 수단으로 활용하고 있으며, C4ISR 체계 역시 IDS와 방화벽을 주요 정보보호 수단으로 활용하고 있다. 그러나, IDS의 예상외의 행위패턴에 대한 잦은 오탐지와 변형된 공격패턴에 대한 미탐지로 인해 C4ISR 체계에서의 IDS의 활용이 제한되고 있다. 이번 연구에서는 IDS 탐색과정에서 변형 공격패턴이나 예상 외의 패턴을 자동 생성하는 IDS 구조를 제안한다. 제안하는 IDS 구조는 패턴의 생성과 검증을 통해 오탐지 또는 미탐지를 감소시킴으로써, C4ISR 체계에서의 정보보호를 향상시킬 것을 기대한다.

• 한국세라믹학회지
• /
• 제21권2호
• /
• pp.143-148
• /
• 1984

In this study we mainly dealt with the effects of organic retarder(calcium lignosulfate) on the early hydration process of clinker minerals. From a consideration of the hydration process of tricalcium silicate $(C_3S)$ tricalcium silicate $(C_3S)$-tricalcium aluminate $(C_3A)$ tricalcium silicate $(C_3S)$-tetracalcium aluminof-errite $(C_4AF)$ systems with calcium lignosulfate the following results were obtained. 1. when 0.25wt% of CLS was added to $C_3S$ the hydration process was progressed normally but adding of 0.5wt% its hydration was greatly retarded. 2. The hydration of $C_3S$-$C_3A$ system was progressed normally up to 0.5wt% but by adding gypsum its hydration was retarded slightly. 3. The hydration of $C_3S$-$C_4AF$ system was greatly retarded even with 0.25wt% of CLS but by adding gypsum its hydration process was recovered normally.

• 한국경영과학회지
• /
• 제36권4호
• /
• pp.1-16
• /
• 2011

It is important not only to introduce the C4I(Command and Control, Communication, Computer, Intelligence) system for realizing the NCW(Network Centric Warfare) but also to evaluate the synergistic effect by the C4I system. However, the study effort for evaluating the system's synergistic effect is insufficient compared with introducing the system. Therefore, in this paper, we proposed a model that measures the synergistic effect of combat power by the warfare information system. To measure the synergistic effect of warfare information system, the network power must be considered, so we also proposed a new methodology for measurement of network power based on SNA(Social Network Analysis), not Metcalfe's law. A model we proposed is a model that measures the raised combat power by the network effectiveness. The methodology and model we proposed in this paper will be used usefully to analyze the practical effect of constructing future warfare information system.

• 한국통신학회논문지
• /
• 제25권3A호
• /
• pp.352-361
• /
• 2000

본 논문에서는 주파수 다중경로 페이딩과 Near/Gar 영향을 받는 Multi-Carrier CDMA 시스템의 성능을 분석하였다. 성능 분석을 위해 사용한 파라미터들을 Multi-Carrier의 수, 다중사용자의 수, RAKE 수신기의 가지수, 주파수 선택성 다중경로 페이딩의 감쇄지수, 그리고 CDMA 다중사용자의 분포와 세기이다. Multi-Carrier CDMA 시스템에서 Near/Far 영향을 분석하기 위하여 3가지 간섭 분포 모델을 설정하였다. 첫 번째 모델은 다중사용자가 간섭파 대 반송파 비인 I/C를 -4dB에서 4dB 사이에서 2 dB씩의 차이를 가지며 20%씩 균일하게 분포하는 경우이다. 두 번째 모델은 다중사용자가 I/C 비를-2dB에서 2dB 사이에서 2dB씩의 차이를 가지며 33.3%씩 균일하게 분포하는 경우이다. 그리고 세 번재 모델은 모든 다중사용자가 I/C가 0dB로 신호 전력과 간섭전력이 동일하게 분포하여 전력이 완전하게 제어된 경우이다. 그리고 본 논문에서는 주파수 선택성 다중경로 페이딩의 영향을 감소시키기위하여 RAKE 수신기를 채용한 Multi-Carrier CDMA 시스템을 제안하였다. 이 시스템에서는 제시한 3가지 간섭 분포 모델중에서 세 번째 모델(완전 전력제어가 된 경우)이 가장 좋은 성능을 나타내었고, 간섭파의 전력과 신호파의 전력차이가 적을수록 희망 신호에 영향을 주는 간섭 신호의 전력량이 적어서 Multi-Carrier CDMA 시스템의 성능이 향상됨을 알 수 있었다.

• 대한간호학회지
• /
• 제9권2호
• /
• pp.73-83
• /
• 1979

The objectives of this study have been conducted to establish effective clinical teaching program to I.C.U in terms of proper assignment of the clients for the students, proper rotation schedule, priorities in critical nursing problems and selection of the teaching and learning. We have analyzed statistically 1,850 patients who have been admitted during a period from January 1977 to October 31 1979 in Ewha Woman's University Hospital. The results are as follows: 1. The proportion to the total inpatients number was 6.5% and mortality rate was 16.3%. 2. The average hospitalized days were 5.8 days in I.C.U and the total death was occured from 1 st hospital day to 5th hospital day. So it shows a certain difficulties for clinical experiences of the senior students in I.C.U. 3. In the age of the death, 41.3% of the patients were in the 41-60 year age group. It shows highest mortality rate in socially active and productive age groups. 4. The mortality rates of the departments of the medicine was 18.7%, general surgery 18.5%, and neurosurgery 14.7%. 5. The number of patients admitted to the department of neurosystem was 30.6%, cardiovascular system 22.6%, respiratory system 11.1 ％ and urinary system 2.9%. 6. On utilizing instruments and machine for diagnosis and client's assessment in I.C.U, they have utilized everything a usual. But they never utilize angiogram and cardiac catheterization in cardiovascular system, and retroperitoneal pneumography in the urologic system. Further more we would recommend as follows 1. In consideration of the average hospital days and the date of death, the rotation program for clincal experience need to be adjusted as continuing practice program in apposite to current alternative practice program for comprehensive nursing care. 2. Socioeconomic needs for the patient's families and himself should be emphasized by the students in addition to physical needs. 3. Course content for critical care might be built up in considering of core disease centered nursing problems. 4. The diagnostic procedures and client's assessment items which could not experience in our university hospital by the students might be considered and refilled as filled trips to another hospital and visual aids.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 D
• /
• pp.781-783
• /
• 2000

1bit full adder have 3 input (including carry_in) and 2 outputs(Sum and Carry_out). Because of 1 bit full adder's propagation delay. We usually use 4-bit binary full adder with fast carry, 74LS283. The 74LS283 is positive logic circuit chip. But the logic function of binary adder is symmetrical, so it can be possible to use it not only positive logic but also the negative logic. This thesis use symmetrical property. such as $C_{i+1}(\bar{a_i}\bar{b_i}\bar{c_i})=C_{i+1}{\bar}(a_i,\;b_i,\;c_i)$ and $S_i(\bar{a_i}\bar{b_i}\bar{c_i})=\bar{S_i}(a_i,\;b_i,\;c_i)$. And prove this property with logic operation. Using these property, the 74LS283 adder is possile as the negation logic circuit. It's very useful to use the chip in negative logic. because many system chip is negative logic circuit. for example when we have negative logic chip with 74LS283. we don't need any not gate for 74LS283 input, and just use output of adder(74LS283) as the negation of original output.