• 대한산업공학회지
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• 제30권1호
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• pp.17-26
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• 2004

In this study, the usability evaluation of a menu-structure was performed using spreading activation model with respect to human's memory retrieval. Spreading Activation Model is effectively used to understand the process of information retrieval, so it can be used as a theoretical background for modeling of the process of human's information retrieval. For spreading activation test (SAT), subjects were presented with 67 pairs of menu titles, which consist of a menu title in the high level menu item and a menu title for the next lower level menu item, from Korea University's web site. For performance tests, three scenarios were developed with longer reaction times and ambiguous associations found in the SAT to reflect the existing problems of the website. As a result, the SAT was found to bean effective tool to enhance the website usability because the SAT could bea substitute for the performance test with a high correlation $({\rho}=0.735,\;{\alpha}=0.05)$. After remaining menu titles with slow reaction times and ambiguous associations found in SAT, the website usability was significantly improved with faster reaction times and less ambiguous associations proven with smaller number of web-page visits. Therefore, the SAT could be used as a methodology to design and evaluate the user-centered menu structure related to human's association structure.

• Toxicological Research
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• 제35권4호
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• pp.395-402
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• 2019

Subcutaneous adipose tissue (SAT) accumulation is a constitutional disorder resulting from metabolic syndrome. Although surgical and non-surgical methods for reducing SAT exist, patients remain non-compliant because of potential adverse effects and cost. In this study, we developed a new minimally-invasive approach to achieve SAT reduction, using a microneedle (MN) patch prepared from gelatin, which is capable of regulating fat metabolism. Four gelatin types were used: three derived from fish (SA-FG, GT-FG 220, and GT-FG 250), and one from swine (SM-PG 280). We applied gelatin-based MN patches five times over 4 weeks to rats with high-fat diet (HD)-induced obesity, and determined the resulting amount of SAT. We also investigated the histological features and determined the expression levels of fat metabolism-associated genes in SAT using hematoxylin and eosin staining and western blotting, respectively. SAT decreased following treatment with all four gelatin MN patches. Smaller adipocytes were observed in the regions treated with SA-FG, GT-FG 250, and SM-PG 280 MNs, demonstrating a decline in fat accumulation. The expression levels of fat metabolism-associated genes in the MN-treated SAT revealed that GT-FG 220 regulates fatty acid synthase (FASN) protein levels. These findings suggest that gelatin MN patches aid in decreasing the quantity of unwanted SAT by altering lipid metabolism and fat deposition.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.556-558
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• 2022

본 논문에서는 인공지능 알고리즘을 운용할 수 있는 고성능 소형 컴퓨터인 젯슨 나노를 기반으로 차량 추적 기능을 가진 캔위성 시스템을 제안한다. 캔위성 시스템은 캔위성과 지상국으로 구성되며, 캔위성은 대기권 내에서 낙하하며 장착된 센서를 통해 얻은 데이터를 무선통신을 이용해 지상국으로 전송한다. 기존 캔위성은 단순히 수집된 정보를 지상국에 전송하는 임무로 제한되며, 제한된 낙하 시간과 무선통신의 대역폭 제한으로 효율적인 임무 수행에는 한계가 있었다. 본 논문에서 제안하는 젯슨 나노 기반의 캔위성은 사전에 학습된 신경망 모델을 이용하여 공중에서 촬영한 영상에서 차량의 위치를 실시간으로 탐지 후, 2축 모터를 이용하여 카메라를 움직여 차량을 추적한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.39-41
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• 2004

This paper demonstrates the in-house development of the subsystem C&DH in a D-SAT satellite project of Astronautic Technology (M) Sdn. Bhd. (ATSB). D-SAT is a non-imaging satellite. It will carry a dosimeter as the payload for scientific objectives. Since one of the D-SAT project establishment intended objectives is to demonstrate the research and development skill of the ATSB engineers on the satellite system building, most of the subsystems of the D-SAT are developed in-house including the C&DH subsystem. C&DH subsystem plays an important role for managing data handling tasks and general operation of the satellite system. The C&DH development includes the research and study on the hardware and software design, the design of both the hardware and software, the development of the software system, the integration between the software and the hardware system and the implementation of the subsystem into the satellite system. This program allows ATSB to accomplish the engineers with expertise not only in the C&DH subsystem but other subsystems too besides developing knowledge in the management of a space project that covers not only on the technical issues but issues relating to the economic, political and legal issues.

• 대기
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• 제25권3호
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• pp.461-472
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• 2015

The sudden stratospheric warming (SSW), which is characterized by an abrupt increase of polar stratospheric temperature by several tens of degrees in a week, has been known to affect tropospheric weather and climate on sub-seasonal time scale in the boreal winter. Such downward coupling has been often examined in North Atlantic and Europe, but rarely examined in East Asia. In this study, by applying the two definitions of SSW to the reanalysis data, the possible impacts of the SSW events on the surface air temperature (SAT) and tropospheric circulation in East Asia are analyzed. It is found that Eurasian continent, including Siberia and the Northeast Asia, tends to experience anomalously cold SAT for up to sixty days after the SSW events. The resulting SAT anomalies largely resemble those associated with negative Artic Oscillation. However, over East Asia, SSW-related SAT change is weak and not statistically significant. Only during the extreme SSW events when the downward coupling between the stratosphere and troposphere is strong, East Asia exhibits significantly cold SAT anomalies. This relationship is presented by grouping SSW events into those followed by cold SAT anomalies over East Asia and those by warm anomalies for varying threshold values of the SSW events.

• 동력기계공학회지
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• 제17권2호
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• pp.21-28
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• 2013

Phenomenon of droplet impingement with high temperature wall needs to be investigated because atomization process of droplet and cooling process of the wall by the impingement are very important in industry, thus studies concerned with temperature of piston wall have been conducted in spray characteristics analysis of diesel engine. Hence, in this study, we defined $DT_{sat}(=T_w-T_{sat})$ superheat degree of the wall by difference between $T_w$ considering surface temperature of piston in the actual engine and $T_{sat}$ saturation temperature of the fuel and then investigated spray behavior of wall impinging with variance of the boiling process. In this study, in order to analyze wall impingement of droplet in accordance with difference of boiling condition, calculational conditions were set as $DT_{sat}=40K$(nucleate boiling), $DT_{sat}=140K$(transition boiling), and $DT_{sat}=240K$(film boiling). As a result, it can be found that fuel vapor increases and droplet mass decreases in the order of the nucleate boiling, transition boiling, and film boiling.

• Journal of Astronomy and Space Sciences
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• 제32권3호
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• pp.257-268
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• 2015

Characteristics of delta-V requirements for deploying an impactor from a mother-ship at different orbital altitudes are analyzed in order to prepare for a future lunar CubeSat impactor mission. A mother-ship is assumed to be orbiting the moon with a circular orbit at a 90 deg inclination and having 50, 100, 150, 200 km altitudes. Critical design parameters that are directly related to the success of the impactor mission are also analyzed including deploy directions, CubeSat flight time, impact velocity, and associated impact angles. Based on derived delta-V requirements, required thruster burn time and fuel mass are analyzed by adapting four different miniaturized commercial onboard thrusters currently developed for CubeSat applications. As a result, CubeSat impact trajectories as well as thruster burn characteristics deployed at different orbital altitudes are found to satisfy the mission objectives. It is concluded that thrust burn time should considered as the more critical design parameter than the required fuel mass when deducing the onboard propulsion system requirements. Results provided through this work will be helpful in further detailed system definition and design activities for future lunar missions with a CubeSat-based payload.

• 인터넷정보학회논문지
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• 제9권2호
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• pp.89-105
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• 2008

지금까지 테스트 데이터를 자동으로 생성하기 위한 대부분의 연구는 프로그램에 포인터가 존재하지 않는 경우만을 대상으로 하였다. 최근에 포인터가 있는 경우에도 테스트 데이터를 자동으로 생성할 수 있는 방법들이 제안되었지만 테스트할 프로그램 경로를 완전하게 명시해야 하는 경로 기반 방법이거나 프로그램을 실제 실행해야 하는 방법들이다. 이 논문에서는 프로그램 경로를 완전하게 명시하지 않아도 포인터가 있는 프로그램에 대하여 테스트 데이터를 생성할 수 있는 새로운 방법을 제안한다. 제안된 방법은 테스트 데이터 생성 문제를SAT(SATisfiability) 문제로 변환하고 SAT 해결도구를 이용하여 자동으로 테스트 데이터를 생성하는 정적 방법이다. 이를 위해 프로그램을 1차 관계 논리 언어인 Alloy로 변환하고 Alloy 분석기를 통하여 테스트 데이터를 생성한다.

• 한국항공우주학회지
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• 제45권2호
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• pp.154-162
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• 2017

인공위성의 시스템 설계 및 운용에 대한 이해증진을 목적으로 국내에서는 2012년을 시작으로 매년 캔위성 경연대회가 개최되고 있다. 본 논문에서 제안한 캔위성은 2016년 경연대회에 출전한 SCSky(Smart Call from the Sky) CanSat으로, 주요임무는 캔위성에 탑재된 스마트폰을 이용하여 영상통화 연결을 통해 위성체 내 외부 및 비행영상 획득을 목표로 하고 있으며, 임무 구현을 위해 형상기억합금 와이어를 적용한 원격터치시스템을 개발하였다. 아울러 부가적인 임무로 비행 임무동안 보다 넓은 범위의 지상관측영상 획득을 목적으로 형상기억합금스프링을 적용한 광역스캔카메라 메커니즘을 개발하였다. 본 논문에서는 상기 캔위성에 대한 임무를 비롯해 개발 탑재체 및 캔위성 시스템 소개, 최종 비행시험결과에 대하여 서술하였다.

• 정신신체의학
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• 제7권1호
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• pp.42-50
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• 1999

감정표현불능증은 감정과 공상을 언어적으로 표현하는 능력의 어려움을 특징으로 하는 정신기능의 특정 장애를 의미한다. 이는 초기에 정신신체질환에서 언급되었음에도 불구하고 감정표현불능증적 특성은 내과적 그리고 정신과적장애를 가진 환자들에게서 폭 넓게 관찰되고 있다. 본 연구는 Scored Archetypal 9 Test(SAT9)파 한국판 토론토 감정표현불능증 척도-20(TAS-20K)를 사용하여 알코올리즘 환자들에서의 감정표현불능증적 특성을 조사하기 위해 계획되었다. 20명의 알코올리즘 환자들과 24명의 정상대조군이 본 연구를 수행하였다. 결과는 다음과 같다. 1) SAT9과 TAS-20K에서 알코올리즘 환자군은 정상대조군에 비하여 좀 더 alexithymic하였다. 2) 두 군간 성별사이의 감정표현불능증 척도는 통계학적으로 유의한 차이가 없었다. 3) 두 군간 나이나 교육정도와 감정표현불능증 척도사이에는 통계학적으로 유의한 상관은 없었다. 4) SAT9과 TAS-20K은 환자군에서 통계학적으로 유의한 상관을 보여주었다.