• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
• /
• pp.612-615
• /
• 2005

Korea Aerospace Research Institute(KARl) has been receiving Terra and Aqua MODIS data at ground station of Daejeon since July 2002. MODIS data can cover whole East Asia including the Korean Peninsula, Japan and The East China each almost scene and is monitoring ocean, atmosphere and land. By this time, over two thousand scenes have been archived including Terra and Aqua in the storage system and they occupied about over 10TB of disk space. In this study, Web-Downloading system of MODIS data developed on WWW is including following main functions: spectral subset (250m, 500m, 1000m chnnels) Level 1B data of HDF format, result display, ftp download and statistic viewer etc. Users using this system can directly download MODIS data on WWW with a few input parameters. This system is available via the Internet URL after October 2005 on the following, 'http://webmodis.kari.re.kr/'

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.504-509
• /
• 2001

CD-ROM drive is improved in rotation speed up to 10,000 rpm. But Vibration and Noise are also increased simultaneously more and more. So many attempts are tried to reduce the unexpected effects. Most attempts are not enough to cover the increasement of Noise and Vibration. Merely availed tries are accumulated in many part and it makes the structure complicated. The Axiomatic approach could arrange the order of design and estimate the optimum design in good oder. In Axiomatic Approach, the composition is divided by Customer Requirement, Functional Requirement, Design Parameter and Design Matrix in large portion. This method also could show more effective way to design before making a prototype.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.291-296
• /
• 2001

Recently, many methods are studied to analyze the noise of HDD and to reduce it. In this study, the simulation tool(SPATH) was developed to analyze a noise of HDD. The prediction technique of sound pressure level(SPL) of a given structural shape enables us to design a cover and a base with much less vibration and noise. In this paper, we measured the force of disk-spindle motor and predicted SPL from HDD by computational simulation. To get a SPL of HDD by computational simulation, modal analysis and forced vibration analysis were performed with ANSYS, and sound radiation was computed using SYSNOISE. The calculated results were compared with experimental results and a good agreement was obtained.

• 정보저장시스템학회:학술대회논문집
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.14-15
• /
• 2005

In near-field recording (NFR) optics using solid immersion lens (SIL), near-field air gap induces unwanted spherical aberration, defocus and astigmatism. This phenomenon can be explained with the apodization of phase and amplitude between each linearly polarized light. In this paper, we analyzed the effect of phase and amplitude apodization with the fundamental multiple beam interference theory, and we compared resultant diffracted patterns on the image plane for the Si-disk first surface media structure and cover-layer incident media structure.

• 소성∙가공
• /
• 제9권6호
• /
• pp.590-597
• /
• 2000

A finite element formulation lot the simulation of axisymmetric sheet hydroforming is proposed, and an implicit program is coded. In order to describe normal anisotropy of steel sheet, Hill's non-quadratic yield function (Hill, 1979) is employed. Frictional contacts among sheet surface, rigid tool surface, and flexible hydrostatic pressure are considered using mesh normal vectors based on finite element of the sheet. Applied hydraulic pressure is also considered as a function of forming rate and time and treated as an external loading. The complete set of the governing relations comprising equilibrium and interfacial equations is approximately linearized for Newton-Raphson algorithm. In order to verify the validity of the developed finite element formulation, the axisymmetric bulge test is simulated. Simulation results are compared with other FEM results and experimental measurements and showed good agreements. In axisymmetric hydroforming processes of a disk cover, formability changes are observed according to the hydraulic pressure curve changes.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2002년도 추계 학술대회논문집
• /
• pp.114-119
• /
• 2002

A numerical model is employed for design of a spinner device to dry the 5-th generation LCD glass panel. The turbulent flow in a spinner is driven by rotation of a large disk and suction by the exhaust system connected to vacuum chamber, which is simulated by using the FLUENT package. Based on numerical simulation, the required capacity of exhaust system is assessed. The effects of the presence of cover on the flow characteristics are examined. A computational trouble shooting is attempted to resolve the problem of panel rising which occurred in real experiments.

• 한국정보과학회논문지:데이타베이스
• /
• 제29권1호
• /
• pp.79-88
• /
• 2002

인터넷에서 사용되는 많은 데이터들이 XML로 표현되고 있는 추세이다. 이러한 XML 데이터는 트리 형태로 표현되므로 이것을 저장하고 질의하는 시스템으로 그 모델링 능력 때문에 객체 저장소가 적합하다. 객체 저장소에서 XML의 각 노드는 객체로 저장된다. XML 질의의 특징은 정규 경로식으로 표현되는 것이며 이것은 XML 트리의 각 객체를 탐색하면서 처리된다. 정규 경로식을 지원하기 위하여 여러 인덱스들이 제안되었지만 이러한 인덱스들은 디스크 공간이라는 제약 때문에 모든 가능한 경로에 대한 인덱스를 제공하지는 못한다. 이러한 상태에서 정규 경로식을 잘 지원하기 위해서 블록 탐색과 시그니처 방법을 이용하여 질의를 효과적으로 처리하는 최적 객체 탐색 기법을 제안하였다. 시그니처는 트리의 각 노드에 시그니처를 첨가하여 탐색 범위를 줄이는 것이다. 블록 탐색은 한 페이지 내에 있는 접근 가능한 객체들을 미리 처리함으로써 디스크 I/O를 줄이는 것이다. 이와 같은 두가지 방법을 같이 이용하면 일반적인 질의 처리보다 월등히 나은 성능을 보인다는 것을 실험을 통하여 보였다.

• Journal of Astronomy and Space Sciences
• /
• 제38권4호
• /
• pp.203-215
• /
• 2021

The auroral observation has been started at Jang Bogo Station (JBS), Antarctica by using a visible All-sky camera (v-ASC) in 2018 to routinely monitor the aurora in association with the simultaneous observations of the ionosphere, thermosphere and magnetosphere at the station. In this article, the auroral observations are introduced with the analysis procedure to recognize the aurora from the v-ASC image data and to compute the auroral occurrences and the initial results on their spatial and temporal distributions are presented. The auroral occurrences are mostly confined to the northern horizon in the evening sector and extend to the zenith from the northwest to cover almost the entire sky disk over JBS at around 08 MLT (magnetic local time; 03 LT) and then retract to the northeast in the morning sector. At near the magnetic local noon, the occurrences are horizontally distributed in the northern sky disk, which shows the auroral occurrences in the cusp region. The results of the auroral occurrences indicate that JBS is located most of the time in the polar cap near the poleward boundary of the auroral oval in the nightside and approaches closer to the oval in the morning sector. At around 08 MLT (03 LT), JBS is located within the auroral oval and then moves away from it, finally being located in the cusp region at the magnetic local noon, which indicates that the location of JBS turns out to be ideal to investigate the variabilities of the poleward boundary of the auroral oval from long-term observations of the auroral occurrences. The future plan for the ground auroral observations near JBS is presented.

• Anatomy and Cell Biology
• /
• 제56권2호
• /
• pp.252-258
• /
• 2023

The human fetal sacroiliac joint (SIJ) is characterized by unequal development of the paired bones and delayed cavitation. Thus, during the long in utero period, the bony ilium becomes adjacent to the cartilaginous sacrum. This morphology may be analogous to that of the temporomandibular joint (TMJ). We examined horizontal histological sections of 24 fetuses at 10-30 weeks and compared the timing and sequences of joint cartilage development, cavitation, and ossification of the ilium. We also examined histological sections of the TMJ and humeroradial joint, because these also contain a disk or disk-like structure. In the ilium, endochondral ossification started in the anterior side of the SIJ, extended posteriorly and reached the joint at 12 weeks GA, and then extended over the joint at 15 weeks GA. Likewise, the joint cartilage appeared at the anterior end of the future SIJ at 12 weeks GA, and extended along the bony ilium posteriorly to cover the entire SIJ at 26 weeks GA. The cavitation started at 15 weeks GA. Therefore, joint cartilage development seemed to follow the ossification of the ilium by extending along the SIJ, and cavitation then occurred. This sequence "ossification, followed by joint cartilage formation, and then cavitation" did not occur in the TMJ or humeroradial joint. The TMJ had a periosteum-like membrane that covered the joint surface, but the humeroradial joint did not. After muscle contraction starts, it is likely that the mechanical stress from the bony ilium induces development of joint cartilage.

• Restorative Dentistry and Endodontics
• /
• 제31권4호
• /
• pp.282-289
• /
• 2006

본 연구의 목적은 5급 복합레진 수복물에 각종 레진 전색제를 적용한 후, 수복물의 교합면측과 치은측 변연 미세누출에 대한 레진 전색제의 감소효과를 평가하기 위하여 시행하였다. 40개의 발거된 대구치의 협면 치경부에 5급 와동을 형성하고 복합레진을 충전한 후, 사용된 레진 전색제에 따라 다음 과 같이 4개의 군으로 분류하였다; 복합레진 표면과 변연부에 레진 전색제를 적용하지 않은 대조군, 복합레진 표면과 변연부에 각각 레진 전색제를 적용한 Fortify Plus 군, BisCover 군 및 PermaSeal 군으로 분류하였다. 각 군의 시편을 실온의 증류수에 24시간 동안 보관한 후, $5^{\circ}C$와 $55^{\circ}C$에서 1,000회의 열 순환을 시행하고 2% methylene blue 용액에 4시간동안 침적시켰다. 각 치아는 저속의 diamond disk 를 이용하여 각 수복물의 중앙부를 따라 협, 설 방향으로 양분 하고 20배율의 광학 입체현미경 하에서 각각 교합면측과 치은측 변연 미세누출을 평가하였다. 각 군의 교합면측과 치은측 변연 미세누출에 대한 유의성을 검정을 시행하여 다음과 같은 결과를 얻었다. 1. 교합면측 변연 미세누출은 사용된 레진 전색제 간에 통계학적으로 유의한 차이를 나타내지 않았다. 2. 치은측 변연 미세누출은 대조군과 Fortify Plus 군이 PermaSeal 군보다 통계학적으로 높게 나타났으며, 또한 Fortify Plus 군은 Biscover 군보다 통계학적으로 높은 변연 미세누출을 나타내었다 (p < 0.05). 3. 대조군과 Fortify Plus 군은 교합면측 보다 치은측 변연에서 통계학적으로 더 높은 미세누출을 나타내었다 (p < 0.05). 4. BisCover 군과 PermaSeal 군은 교합면측과 치은측의 변연 미세누출 간에 통계학적으로 유의한 차이를 나타내지 않았다. 본 연구를 종합하면, 5급 복합레진 수복물의 교합면측 변연 미세누출에 대한 레진 전색제의 감소효과는 크게 나타나지 않았지만, 치은측 변연 미세누출에 대한 레진 전색제의 감소효과는 사용된 레진 전색제에 따라 서로 다르게 나타났다.