• Proceedings of the KIEE Conference
• /
• 2001.04a
• /
• pp.485-487
• /
• 2001

Electric power has traditionally been supplied to the demander through power generation, its transmission, and final distribution system. It is, however, expected that the various dispersed power system will be located near demanders and act as a power source based on the efficient management of electric power demanders and the optimal utilization of substitute energy. More stable electric power and efficient utilization of various power sources can be guranteed through the connection of the dispersed power system into the existing power system. It is the purpose of this study that, in the case of the connection of dispersed power system into the existing distribution line, effects of the connection on the power quality and plans for protection of power equipments are discussed and solutions of them are proposed.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.433-436
• /
• 2011

스마트폰, 아이패드, 갤력시S, 탭 등 비약적인 과학기술의 발전으로 생활수준이 향상함에 따라, 한강 르네상스 및 4대강 살리기 사업, 각종 생태하천복원 등 새로운 수변문화공간 구축을 위한 공공 사업에서 첨단무선통신기술을 융합한 신개념의 서비스와 문화가 요구되고 있다. 서울시, 서울인근 지역의 강, 하천에 유량이 유입되는 주요지점에 수중환경감지 센서설치. 주변오염지역 감지 및 수중환경 생태를 실시간 감지하여 이상 징후(BOD, COD, DO, 전도, 탁도 등)발생이 예상되는 주변 오염원인 공장, 폐기처리장, 폐수처리장 등의 시설물을 D/B 관리하여 오염원 관련 피해주민에게 실시간 공지하여 대형사고 예방 및 청정하천 수중환경유지를 목표로 한다. 본 논문에서는 수중환경(하천, 호수, 강 등)대한 지능적이고, 효율적인 관리를 위해 센서수중환경에 적합한 4세대 센서 보드 설계 및 블록다이어그램 설계, 통신기술, 인터페이스 개발을 통해 수중환경에 적합한 센서 및 데이터 획득기술 개발한다.

• Korean Journal of Materials Research
• /
• v.14 no.4
• /
• pp.251-259
• /
• 2004

In the development of the advanced spent fuel management process based on the molten salt technology, it is essential to choose the optimum material for the process equipment handling molten salt. Corrosion behavior of Ni 200 and Ni-base alloys in molten salt of LiCl-$Li_2$O under oxidation atmosphere was investigated in the temperature range of $650～800^{\circ}C$ for 24～312 hrs. The order of corrosion rate was Ni 200 > Inconel 690 > Inconel 601 > Inconel 600. Inconel 600 alloy showed the highest corrosion resistance among the examined alloys, but Ni 200 exhibited the highest corrosion rate. Corrosion products of Inconel 600 and Inconel 601 were $Cr_2$$O_3$ and $NiFe_2$$O_4$. In case of Inconel 690, a single layer of $CrO_2$$O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2$O$_4$ and inner layer of $Cr_2$$O_3$ were formed with increase of corrosion time. Inconel 600 showed local corrosion behavior and Inconel 601, 690 showed uniform corrosion behavior.

• Journal of the Korean Society of Safety
• /
• v.11 no.2
• /
• pp.16-24
• /
• 1996

In this study we simulate the fatigue test of a compact tension specimen and obtain the displacements, stresses and strains by using the finite element method. And we examine the path independency of $\Delta$J integral values and compare it with $\Delta$J integral values calculated from load-load line displacement curve. From the results of this study, we can find that $\Delta$J integral show the path Independency for saturated materials. We can also find that the path independency of $\Delta$J Is not satisfied when different material Is assumed near the crack tip, but the difference in $\Delta$J is small. And $\Delta$J integral values calculated from load-load line displacement is very analogous with those from integration path but always have lower values than those from integration paths. In the case of crack closing, we found that $\Delta$J integral values from load-load line displacement should be calculated with the load Increment values based on the crack opening point. The unsaturated material is also simulated and its $\Delta$J shows different values according to the path, but the difference is small.

• Journal of the Korean Society of Safety
• /
• v.12 no.2
• /
• pp.45-56
• /
• 1997

Fracture behavior of ex-serviced 1Cr-0.5Mo steel was measured at room($24^{\circ}C$) and elevated($538^{\circ}C$) temperature and compared with that measured with virgin 1Cr-0.5Mo steel. Compact C(T) specimens were machined from the base and welded test materials. In case of the C(T) specimens of the weld, fatigue precrack was introduced along the fusion line so that following crack growth should occurs along the region of heat affected zone. It was observed that the J-R curve of the serviced material was significantly lower than that of the virgin material at room temperature. Brittle fracture was observed in the serviced material. On the other hand, at elevated temperature no noticeable difference was found between the J-R curves of the virgin and the serviced material. The measured J-R curves were also compared with those of the 1.25Cr-0.5Mo steel obtained from the other literatures. Optical microscopy and SEM examination of the serviced material reveal the carbide in/along the grain boundary which shows material degradation due to long-term usage. An example of application of the measured J-R curves is shown.

• Smart Media Journal
• /
• v.6 no.3
• /
• pp.9-14
• /
• 2017

This paper is a study on the hardware implementation of the encryption and decryption block of the lightweight block cipher algorithm LEA which can be used for tiny devices in IoT environment. It accepts all secret keys with 128 bit, 192 bit, and 256 bit sizes and aims at the integrated implementation of encryption and decryption functions. It describes design results of applying pipeline method for performance enhancement. When a decryption function is executed, round keys are used in reverse order of encryption function. An efficient hardware implementation method for minimizing performance degradation are suggested. Considering the number of rounds are 24, 28, or 32 times according to the size of secret keys, pipeline of LEA is implemented so that 4 round function operations are executed in each pipeline stage.

• The KIPS Transactions:PartB
• /
• v.8B no.1
• /
• pp.43-49
• /
• 2001

이동통신 채널과 같이 에러 발생율이 높은 환경에서 부호화된 비디오를 전송할 때 채널에어에 손상된 비트스트림은 복호되기 어려울 뿐만 아니라, 비트스트림의 다른 부분으로까지 에러를 전파시킨다. 한 프레임에 손실블록이 있을 때 기존방법에서는 주변블록들의 움직임벡터 평균을 구하거나 비슷한 예측을 통해 손실블록의 움직임벡터를 복원한다. 그러나 손실블록이 움직이는 객체의 경계부근에서 발생할 때 기존방법은 효율적이지 못한다. 따라서 제안 알고리즘은 기존방법보다 정확한 움직임벡터를 예측하기 위해 손실블록의 주변블록들 중세서 동일한 움직임을 갖는 블록들로 구성된 영역을 찾은 후, 동일움직임영역에 포함된 블록들의 움직임벡터를 이용하여 손실된 블록을 복원한다. 실험결과 제안방법이 기존방법에 비해 PSNR과 시각적인 화질면에서 우수한 성능을 보임을 알 수 있다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.20 no.6
• /
• pp.209-220
• /
• 2010

Evaluating performance in public sector aims to enhance the efficiency of organizations. Evaluating the efficiency which is the ratio between input and output, organizations set directions of improvement. This research applied Data Envelopment Analysis(DEA) useful to evaluating the efficiency of organizations in public sector. Decision Making Units(DMU) of this research are 21 Information Security Organizations of departments/agencies. As the results, the mean of efficiency score of 21 DMUs is a little more than 50%. Means of departments(8 DMUs) and agencies/committees(11 DMUs) are similar to the total efficiency score. For these results, the decision makers of the information security organizations in public sector have to strive to improve the inefficiency.

• The Journal of Korean Physical Therapy
• /
• v.15 no.3
• /
• pp.346-360
• /
• 2003

The purpose of this study was to evaluate effects of education and stabilization exercise of lumbar neutral zone is range of motion and pain of lumbar spine on the with non-specific low back pain. And the randomly selected each twenty patients out of the forty non-specific low back pain patients were classified as an stabilization exercise group and the other the patients were in a control group. stabilization exercise group in non-specific low back pain patients participated in exercise program of Richardson & Jull (1995) four week from October 1st, 2002 to February 28st, 2003 in Daegu 00 hospital. The conclusion were as follows: 1. After 4 weeks of therapy, Visual analogue scale in stabilization exercise group and control group with non-specific low back pain patients were not significantly decreased(p>.05). 2. Remodified Schober test in range of motion lumbar spine of stabilization exercise group and control group with non-specific low back pain patients were significantly increased(p<.05). 3. Finger-to-Floor test in range of motion whole spine of stabilization exercise group and control group with non-specific low back pain patients were not significantly increased(p>.05). 4. Visual analogue scale, Remodified Schober test and Finger-to-Floor test in pre and post treatment of stabilization exercise group and control group with non-specific low back pain patients were significant different(p<.05). 5. Visual analogue scale, Remodified Schober test and Finger-to-Floor test in stabilization exercise group and control group with non-specific low back pain patients were not significant different(p>.05).

• Journal of The Korean Dental Society of Anesthesiology
• /
• v.7 no.1
• /
• pp.1-5
• /
• 2007

Background: It is well known that nasotracheal intubation is comfort for patient compared to oral intubation. We sometimes delay extubation when it is thought that the patient can not maintain airway, or there may be other emergency associated with airway. And we sometimes experience complaint of discomfort of nasotracheal tube. But, we could not find any report on degree of discomfort of delayed nasotracheal intubation. Methods: Eighteen patients in whom extubation of nasotraceal tube was delayed after operation because of difficulties of airway mamagement were selected. We surveyed the discomfort of nasotracheal tube with 0 to 10 visual analogue scale (VAS) and compared with the pain of operation site (VAS). Result: The VAS of nasotracheal intubation was $6.7{\pm}3.4$, and VAS of the primary operation site was $3.5{\pm}2.4$, and VAS of flap harvest site was $5.5{\pm}2.7$. 10 of the patients complained of nasotracheal suction extremely and 6 patients complained of respiratory difficulties. Conclusions: Nasotracheal intubation was discomfort and there must be intervention.