• 한국소음진동공학회논문집
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• 제12권10호
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• pp.749-757
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• 2002

Excessive vibration in flexible structures is a problem encountered in many different fields, causing fatigue of structural components. Passive techniques, though sometimes limited in their capabilities, have been used in the past to attenuate vibrations. Recently active techniques have been developed to enhance vibration control performance beyond that provided by their passive counterparts. Most often, the focus of active control methods has been to suppress structure displacements. In cases where vibration results in structure failures, displacement suppression may not be the best choice of control approaches (it can, in fact, increase dynamic loads which would be even more harmful to supports) . This paper presents two optimal control methods for attenuating steady state vibrations in flexible structures. One method minimizes shaft displacements while another minimizes dynamic reaction forces. The two methods are applied to a model of a typical flexible structure system and their results are compared. It is found that displacement minimization can increase loads, while load minimization decreases loads.

• 한국통신학회논문지
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• 제29권5C호
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• pp.673-682
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• 2004

적응 빔포밍(beam-forming)기법은 디지털보청기 시스템에서 노이즈를 제거하기 위한 적절한 방식이다. 적응 빔포밍 기법은 디지털 신호처리프로세서의 발전과 더불어 최근에 주목을 받고 있는 방식으로 신호처리 과정에서 일반적으로 LMS(Least Mean Square)알고리즘을 사용하여 웨이트 벡터를 업데이트 시킨다. 본 논문에서는 신호의 환경에 따라 적응상수가 변화하는 가변스텝사이즈 알고리즘을 적용한 고속 웨이블렛 기반 적응알고리즘를 제안한다. 제안한 알고리즘을 적응 빔포머 방식인 디지털보청기 시스템에 적용하여 기존 시간영역 알고리즘과 그 특성을 비교하여 그 결과 제안한 알고리즘이 디지털보청기 시스템에 적합함을 입증한다. 그리고 제안한 알고리즘은 계산량에서도 시스템의 환경변화에도 안정하게 수렴한다는 장점이 있는 것을 보인다.

• 천문학회보
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• 제42권2호
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• pp.84.3-85
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• 2017

Korea Astronomy and Space Science Institute (KASI) has been developing the Camera System for the Total Solar Eclipse (TSE) observation. In 2016 we have assembled a simple camera system consisting of a commercial camera lens, a polarizer, bandpass filters, and a Canon camera to observe the solar corona during the Total Solar Eclipse in Indonesia. For 2017 TSE observation, we have studied and adapted the compact coronagraph design proposed by NASA. The compact coronagraph design dramatically reduces the volume and weight, and used for TSE observation. The camera is used to test and verify key components including function of bandpass filter, polarizer, and CCD during observing the Total Solar Eclipse. In this poster we focus on optical engineering works including designing, analyzing, testing, and building for the TSE observation.

• Animal cells and systems
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• 제3권4호
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• pp.359-363
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• 1999

Urochordates, the most primitive group in phylum Chordata, are mostly sessile as adults although some are free living. Presently, the ancestral stock of urochordates as weir as chordates has been the focus of interest and two conflicting hypotheses have been presented. A free swimming ancestor is one and a sessile, filter feeding ancestor is the other. To clarify the phylogenetic relationships within the urochordates, 22 urochordates and five others as outgroups were used. And we applied neighbor joining, maximum likelihood, and maximum parsimony methods to partial 18S rDNA sequences. The inferred phylogeny in all analyses indicates that order Aplousobranchia of class Ascidiacea appears to be the most ancestral group among urochordates. But it is not clear for the low bootstrap value. The remaining two orders of ascidians, Phlebobranchia and Stolidobranchia, form monophyletic groups respectively, which are well supported by high bootstrap values. These two orders are closer to classes of Thaliacea and Appendicularia than to the Aplousobranchia. While class Appendicularia is strongly supported by the monophyletic group, the phylogenetic position of class Thaliacea is unclear in this study.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.55-57
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• 2007

$CO_2$ laser sees that is most suitable to get this effect through minimum formation damage and advantage that is root enemy of effect that happen in minimum cellular tissue depth of 0.1mm is stable living body organization or internal organs institution. Formation damage by ten can be related in formation's kind or energy density, length of evaporation time. If shorten evaporation time, surroundings cellular thermal damage 200 - because happen within 400ums laser beam in rain focus sacred ground surroundings cellular, tissue without vitiation me by evaporation Poe of very small floor as is clean steam can. Application is possible to vulva cuticle cousins by a paternal aunt quantity, uterine cancer, cuticle tumor by laser system that $CO_2$ laser gets into standard in obstetrics and gynecology application. Because effect that super pulse output is ten enemies of laser if uniformity one pulse durations are short almost is decreased, most of all pulse module special quality of pulse style $CO_2$ laser for obstetrics and gynecology mode stabilization by weight very, in this research to get into short pulse duration and higher frequency density, do switching by high frequency in DC-DC Converter output DC's ripple high frequency to be changed, high frequency done current ripple amount of condenser for output filter greatly reduce can. Ripple of output approximately to Zero realization applying possible inductor realization through a special quality experiment do.

• Preventive Nutrition and Food Science
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• 제11권4호
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• pp.305-310
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• 2006

The Web is an important source of information for health care consumers, and the resources they find on the Web have a direct affect on their health outcomes. Despite the enormous benefits of online health care, the quality of health information on the Internet is an area of increasing concern. Therefore, there's a need to develop quality assessment tools that can filter out poor quality online health information. The purpose of this study is to explore the critical attributes for assessing website quality and for developing quality assessment measurements. We completed three focus group discussions with 24 participants that were administered by a moderator and based on specifically focused group questions. The results suggest that the most important quality criteria, as identified by the respondents, were related to issues of credibility and accuracy. To determine the credibility of Internet health information, the respondents stated one must consider the following: the information source, disclosure of the author's or organization's credentials/qualifications, disclosure of ownership and the updating of the content. For the accuracy of content, elements such as a statement of purpose, evidence-based information, relevance and completeness should be considered. Interactivity, accessibility, and design were additional quality criteria.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권4호
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• pp.1555-1570
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• 2016

For monitoring forest fires, a real-time system to prevent fires in wider areas should be supported consistently. However, there has still been a lack of the support for real-time system related to forest fire monitoring. In addition, the 'real-time' processing in a forest fire detection system can lead to excessive consumption of energy. To solve these problems, the intelligent data acquisition of sensing nodes is required, and the maximum energy savings as well as rapid and accurate detection by flame sensors need to be done. In this regard, this paper proposes a node built-in filter algorithm for intelligent data collection of sensing nodes for the rapid detection of forest fires with focus on reducing the power consumption of the remote sensing nodes and providing efficient wireless sensor network-based forest environment monitoring in terms of data transmission, network stability and data acquisition. The experimental result showed that battery life can be extended through the intelligent sampling of remote sensing nodes, and the average accuracy of the measurement of flame detection based on the distance is 44%.

• Current Optics and Photonics
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• 제4권5호
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• pp.428-433
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• 2020

Recently, the on-chip autofocus (AF) function has become essential to the CMOS image sensor. An auto-focus usually operates using phase detection of the photocurrent difference from a pair of AF pixels that have focused or defocused. However, the phase-detection method requires a pair of AF pixels for comparison of readout. Therefore, the pixel variation may reduce AF performance. In this paper, we propose a color-selective AF pixel with a plasmonic nanostructure in a 0.9 μ㎡ pixel. The suggested AF pixel requires one pixel for AF function. The plasmonic nanostructure uses metal-insulator-metal (MIM) stack arrays instead of a color filter (CF). The color filters are formed at the subwavelength, and they transmit the specific wavelength of light according to the stack period and incident angles. For the optical analysis of the pixel, a finite-difference time-domain (FDTD) simulation was conducted. The analysis showed that the MIM stack arrays in the pixels perform as an AF pixel. As the primary metric of AF performance, the resulting AF contrasts are 1.8 for the red pixels, 1.6 for green, and 1.5 blue. Based on the simulation results, we confirmed the autofocusing performance of the MIM stack arrays.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.25.3-25.3
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• 2009

To search for the quasars at z > 7 in early universe, we are developing a optical camera which has a $1k\times1k$ deep depletion CCD chip, with later planned upgrade to HAWAII-2RG infrared array. We are going to attach the camera to the cassegrain focus of Otto Struve 2.1m telescope at McDonald observatory of University of Texas at Austin, USA. We present the design of a hardware interface to attach the CCD camera to the telescope. It consists of focal reducer, filter wheel, and guiding camera. Focal reducer is needed to reduce the long f-ratio (f/13.7) down to about 4 for wide field of view. The guiding camera design is based on that of DIAFI offset guider which developed for the McDonald 2.7m telescope.

• 한국실내디자인학회논문집
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• 제23권1호
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• pp.34-42
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• 2014

The early post-war modern architecture introduced to Korea in the 60's and 70's have reached its 50 year cycle to emerge as candidates for the registered heritage. However, conservation is a complicated topic when applied to modern architecture due to its social and political status among general public, and is often a sacrificial target for demolition or insensitive alteration. This research tries to identify significant values extracted from the intrinsic characteristics of modern architecture, that can be applied to conducting successful renovation projects on modern architecture. The conservational values of modern architecture to be maintained are identified in this paper as: flexible open space, material and structural system, and extension of interior-exterior relation. These values are examined through the filter of comparative analysis on domestic and international conservation standards, along with cross-examination on recently renovated local works performed on the modern architecture of the period. This research aims to bring focus on conducting respectful conservation and renovation to modern architecture by identifying the significant values that is intrinsic to the modern architecture and is worth preserving.