• International Journal of Precision Engineering and Manufacturing
• /
• 제7권2호
• /
• pp.41-45
• /
• 2006

This paper deals with human spatial cognition using visual and auditory stimulation. More specially, this investigation is to observe the relationship between the head and the eye motor system for the localization of visual target direction in space and to try to describe what is the role of right-side versus left-side pinna. In the experiment of visual stimulation, nineteen red LEDs (Luminescent Diodes, Brightness: $210\;cd/^2$) arrayed in the horizontal plane of the surrounding panel are used. Here the LEDs are located 10 degrees apart from each other. Physiological parameters such as EOG (Electro-Oculography), head movement, and their synergic control are measured by BIOPAC system and 3SPACE FASTRAK. In the experiment of auditory stimulation, one side of the pinna function was distorted intentionally by inserting a short tube in the ear canal. The localization error caused by right and left side pinna distortion was investigated as well. Since a laser pointer showed much less error (0.5%) in localizing target position than FASTRAK (30%) that has been generally used, a laser pointer was used for the pointing task. It was found that harmonic components were not essential for auditory target localization. However, non-harmonic nearby frequency components was found to be more important in localizing the target direction of sound. We have found that the right pinna carries out one of the most important functions in localizing target direction and pure tone with only one frequency component is confusing to be localized. It was also found that the latency time is shorter in self moved tracking (SMT) than eye alone tracking (EAT) and eye hand tracking (EHT). These results can be used in further study on the characterization of human spatial cognition.

• 천문학회지
• /
• 제48권5호
• /
• pp.313-323
• /
• 2015

Active galactic nuclei (AGN) are known for irregular variability on all time scales, down to intra-day variability with relative variations of a few percent within minutes to hours. On such short timescales, unexplored territory, such as the possible existence of a shortest characteristic time scale of activity and the shape of the high frequency end of AGN power spectra, still exists. We present the results of AGN single-dish fast photometry performed with the Korean VLBI Network (KVN). Observations were done in a “anti-correlated” mode using two antennas, with always at least one antenna pointing at the target. This results in an effective time resolution of less than three minutes. We used all four KVN frequencies, 22, 43, 86, and 129 GHz, in order to trace spectral variability, if any. We were able to derive high-quality light curves for 3C 111, 3C 454.3, and BL Lacertae at 22 and 43 GHz, and for 3C 279 at 86 GHz, between May 2012 and April 2013. We performed a detailed statistical analysis in order to assess the levels of variability and the corresponding upper limits. We found upper limits on flux variability ranging from ~1.6% to ~7.6%. The upper limits on the derived brightness temperatures exceed the inverse Compton limit by three to six orders of magnitude. From our results, plus comparison with data obtained by the University of Michigan Radio Astronomy Observatory, we conclude that we have not detected source-intrinsic variability which would have to occur at sub-per cent levels.

• 천문학회보
• /
• 제35권1호
• /
• pp.39.2-39.2
• /
• 2010

In this paper, I present the domestic development of near infrared camera systems for the ground telescope and the space satellite. These systems are the first infrared instruments made for astronomical observation in Korea. KASINICS (KASI Near Infrared Camera System) was developed to be installed on the 1.8m telescope of the Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. KASINICS is equipped with a $512{\times}512$ InSb array enable L band observations as well as J, H, and Ks bands. The field-of-view of the array is $3.3'{\times}3.3'$ with a resolution of 0.39"/pixel. It employs an Offner relay optical system providing a cold stop to eliminate thermal background emission from the telescope structures. From the test observation, limiting magnitudes are J=17.6, H=17.5, Ks=16.1 and L(narrow)=10.0 mag at a signal-to-noise ratio of 10 in an integration time of 100 s. MIRIS (Multi-purpose InfraRed Imaging System) is the main payload of the STSAT-3 in Korea. MIRIS Space Observation Camera (SOC) covers the observation wavelength from $0.9{\mu}m$ to $2.0{\mu}m$ with a wide field of view $3.67^{\circ}{\times}3.67^{\circ}$. The PICNIC HgCdTe detector in a cold box is cooled down below 100K by a micro Stirling cooler of which cooling capacity is 220mW at 77K. MIRIS SOC adopts passive cooling technique to chill the telescope below 200K by pointing to the deep space (3K). The cooling mechanism employs a radiator, a Winston cone baffle, a thermal shield, MLI of 30 layers, and GFRP pipe support in the system. Opto-mechanical analysis was made in order to estimate and compensate possible stresses from the thermal contraction of mounting parts at cryogenic temperatures. Finite Element Analysis (FEA) of mechanical structure was also conducted to ensure safety and stability in launching environments and in orbit. MIRIS SOC will mainly perform the Galactic plane survey with narrow band filters (Pa $\alpha$ and Pa $\alpha$ continuum) and CIB (Cosmic Infrared Background) observation with wide band filters (I and H) driven by a cryogenic stepping motor.

• 천문학회지
• /
• 제52권6호
• /
• pp.227-233
• /
• 2019

We report the performance of the 13.7-meter Taeduk Radio Astronomy Observatory (TRAO) radio telescope. The telescope has been equipped with a new receiver, SEQUOIA-TRAO, a new backend system, FFT2G, and a new VxWorks operating system. The receiver system features a 16-pixel focal plane array using high-performance MMIC preamplifiers; it shows very low system noise levels, with system noise temperatures from 150 K to 450 K at frequencies from 86 to 115 GHz. With the new backend system, we can simultaneously obtain 32 spectra, each with a velocity coverage of 163 km s^-1 and a resolution of 0.04 km s^-1 at 115 GHz. The new operating system, VxWorks, has successfully handled the LMTMC-TRAO observing software. The main observing method is the on-the-fly (OTF) mapping mode; a position-switching mode is available for small-area observations. Remote observing is provided. The antenna surface has been newly adjusted using digital photogrammetry, achieving a rms surface accuracy better than 130 ㎛. The pointing uncertainty is found to be less than 5" over the entire sky. We tested the new receiver system with multi-frequency observations in OTF mode. The aperture efficiencies are 43±1%, 42±1%, 37±1%, and 33±1%, the beam efficiencies are 45±2%, 48±2%, 46±2%, and 41±2% at 86, 98, 110, and 115 GHz, respectively.

• 한국전자파학회논문지
• /
• 제23권1호
• /
• pp.1-13
• /
• 2012

능동 위상 배열레이더(AESA radar: Active Electronically Scanned Array radar)는 전자적으로 빔을 조향함으로써 빔 조향 시간이 비약적으로 빨라져, 기존의 기계식 빔 조향 레이더에 비해 레이더에서 수행할 수 있는 다중 임무처리 능력이 크게 향상되었다. 이러한 다중 임무 처리 능력을 최대화하면서 레이더의 전체 성능을 향상하기 위해, 레이더에 주어진 시간, 에너지, 처리 능력 등의 한정된 자원을 실시간으로 효율적으로 관리, 운용할 수 있는 레이더 자원 관리 기술의 중요성이 크게 대두되었다. 그 중 레이더 빔 스케줄링 기술은 레이더 자원 관리의 핵심적인 요소라 할 수 있다. 본 논문에서는 레이더 빔 스케줄링을 위한 다양한 dispatching rule을 비교 분석하고, 특히 빔의 처리 시간 지연 정도에 따라 SPF(Shortest Processing time First)와 ERF(Earliest Request time First)를 차등적으로 적용하여 빔의 우선 순위를 정하는 dispatching rule을 제안, 그 성능의 우월성을 입증하였다.

• 한국지반공학회지:지반
• /
• 제13권5호
• /
• pp.101-124
• /
• 1997

The root pile system is insitu soil reinforcement technique that uses a series of reticulately installed micropiles. In terms of mechanical improvement by means of grouted reinform ming elements, the root pile system is similar to the soil nailing system. The main difference between root piles and soil nailing are due to the fact that the reinforcing bars in root piles are normally grouted under high pressure and that the alignments of the reinforcing members differ. Recently, the root pile system has been broadly used to stabilize slopes and retain excavations. The accurate design of the root pile system is, however, a very difficult tass owing to geometric variety and statical indetermination, and to the difficulty in the soilfiles interaction analysis. As a result, moat of the current design methods have been heavily dependent on the experiences and approximate approach. This paper proposes a quasi-three dimensional method of analysis for the root pile system applied to the stabilization of slopes. The proposed methods of analysis include i) a technique to estimate the change in borehole radium as a function of the grout pressure as well as a function of the time when the grout pressure is applied, ii) a technique to evaluate quasi -three dimensional limit-equilibrium stability for sliding, iii) a technique to predict the stability with respect to plastic deformation of the soil between adjacent root piles, and iv) a quasi -three dimensional finite element technique to compute stresses and dis placements of the root pile structure barred on the generalized plane strain condition and composite unit cell concept talon형 with considerations of the group effect and knot effect. By using the proposed technique to estimate the change in borehole radius as a function of the grout pressure as well as a function of the time, the estimations are made and compar ed with the Kleyner 8l Krizek's experimental test results. Also by using the proposed quasi-three dimensional analytical method, analyses have been performed with the aim of pointing out the effects of various factors on the interaction behaviors of the root pile system.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권8호
• /
• pp.3307-3312
• /
• 2015

The papillary patterned lesion of thyroid may be challenging with many diagnostic pitfalls. Tumor stroma plays an important part in the determination of the tumor phenotype. CD34 is thought to be involved in the modulation of cell adhesion and signal transduction as CD34(+) fibrocytes are potent antigen-presenting cells. Smooth muscle actin (SMA) positivity could be diagnostic for fibroblast activation during tumorigenesis. We aimed to examine the expression of CD34 and alphaSMA in the stroma of papillary thyroid hyperplasia, papillary thyroid carcinoma and papillary tumors of uncertain malignant potential in order to elucidate their possible differential distribution and roles. A total number of 54 cases with papillary thyroid lesions were studied by routine H&E staining, CD34 and ASMA immunostaining. ASMA was not expressed in benign papillary hyperplastic lesions while it was expressed in papillary carcinoma, indicating that tumors have modulated stroma. Although the stroma was not well developed in papillary lesions with equivocal features of uncertain potentiality, CD34 was notable in such cases with higher incidence in malignant cases. So ASMA as well as CD34 could predict neoplastic behavior, pointing to the importance of the stromal role. Differences between groups suggest that the presence of CD34 + stromal cells is an early event in carcinogensis and is associated with neoplasia, however ASMA+ cells are more likely to be associated with malignant behavior and metastatic potential adding additional tools to the light microscopic picture helping in diagnosis of problematic cases with H&E.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권10호
• /
• pp.5195-5199
• /
• 2012

Objectives: Global cancer statistical data show that India has one of the highest incidence rates of oral cancer worldwide. Early detection is extremely important as it results in lower morbidity and death rates. The present study was undertaken to assess awareness of oral cancer and knowledge of its early signs and risk factors in the general public of the semi-urban Gorakhpur area of Uttar Pradesh (India). It was also intended to educate the same population for early detection by increasing their ability to recognize signs and risk factors. Method: A questionnaire-based household survey was conducted over a period of one month in different parts of Gorakhpur district, a region where tobacco use is apparently very high. A total of 2,093 persons participated in the survey. The collected data were analyzed using SPSS software to assess and associate oral cancer awareness with the prevalence, and abstract risk factors, as well as other confounding variables. Results: The general awareness, knowledge of signs and risk factors of oral cancer were found to be proportionate to the literacy level with the highest rate of awareness being among high school and graduates and lowest among illiterates. It was also observed that on most of these dimensions the younger age groups (<30 years) were significantly more knowledgeable. Conclusion: Overall, the awareness of oral cancer in the high-risk population of Gorakhpur was not satisfactory, pointing to a need for further dissemination of information on this issue and its associated risks. This is especially important for the youngsters, as this may possibly help them keep away from the deleterious habit of tobacco indulgence in any form. If necessary risk factor cessation counselling should be provided.

• 한국콘텐츠학회논문지
• /
• 제16권4호
• /
• pp.624-633
• /
• 2016

빅 데이터의 시대 수많은 정보들이 출몰하고 있고 이를 효과적으로 전달하기 위한 인포그래픽 연구들이 이슈화되고 있지만 신용카드명세서를 통해 전달되는 수치정보에 대한 시각화연구는 그 중요성에 비해 매우 미흡하다. 신용카드이용명세서를 중심으로 수치정보 유형을 분석하여 각 정보특성에 따른 효과적인 시각화방법이 무엇인지 연구하였다. 수치정보의 유형은 비교분석, 시간변화의 추이, 비율, 관계, 범위와 분포 등으로 모색되었고 각 정보의 특성에 적합한 그래프형태로 제작하여 가장 효과적이고 이상적인 시각적 형태를 연구하였다. 따라 본 연구는 수치특성을 갖고 있는 신용카드이용명세서에 나타난 수치정보를 전달하기 위한 효과적인 시각적 형태를 짚어줌으로서 시각화의 기준점을 제시하는 의미가 있다.

• 한국콘텐츠학회논문지
• /
• 제5권2호
• /
• pp.187-197
• /
• 2005

본 논문에서는 위치 기반 서비스에서 이동 객체의 궤적을 색인하기 위해 기존에 제안되었던 TB-트리의 성능을 개선시킬 수 있는 확장된 TB-트리(Extented TB-Tree:ETB-Tree)를 제안한다. ETB-트리는 선행 노드를 직접적으로 접근하기 위해 이동 객체의 처음 세그먼트와 마지막 세그먼트가 저장된 단말 노드를 가리키는 포인터 정보와 더불어 디스크에서의 페이지를 가리키는 페이지 번호를 별도의 테이블에 같이 유지함으로써 저장시 동일한 이동 객체의 선행노드를 빨리 검색할 수 있고, 궤적 질의시에도 바로 디스크에 접근해 해당 객체의 제적들을 검색함으로써 검색 성능을 향상시킬 수 있다. 아울러 ETB-트리는 새로운 이동 객체의 제적 정보가 삽입될 때마다 메모리 상의 트리 구조 뿐만 아니라 디스크에 반영함으로써 트리의 일관성을 유지한다. 마지막으로, 성능 평가를 분석한 결과, 제안하는 색인 기법이 기존의 색인 기법들에 비해 삽입과 제적 질의의 검색 측면에서 더 우수함을 보임을 알 수 있다.