• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.101-110
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• 2000

Population ecology of Rhynchocypris keumgangensis have been investigated at upper part of the Han River in Korea from January to December, 1995. The habitat was low water temperature and clean area, and stream form was Aa. The major cohabitation fish was Phoxinus phoxinus. The total lengths in this population indicated that below 40 mm group is one year old, 40~65 mm group is two years old, 65~80 mm group is three year and the 80 mm longer group is regarded over four years old. There were no differences in total length distribution between the female and the male. The males became sexually mature, when longer than 45 mm and females longer than 65 mm in total length. Spawning season was from April to mid May with the water temperature in $11{\sim}14^{\circ}C$ and the properous period was April. The mean number of eggs in ovary was 1,616. The sex ratio all the year round of the female to the male was 1 : 0.75. The current velocity of the spawning ground was 44 (20~80) cm/sec and water depth was 35 (5~70) cm. Eggs were laied in 5~15 cm deep underneath the immaculate pebbles (2~6 cm). Sex ratio of the female to the male was 1 : 6.90 for spawning behavior.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.36.2-36.2
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• 2013

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation infrared space telescope optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. The focal plane instruments onboard SPICA will enable us to resolve many astronomical key issues from the formation and evolution of galaxies to the planetary formation. The FPC-S (Focal Plane Camera - Sciecne) is a near-infrared instrument proposed by Korea as an international collaboration. Owing to the capability of both low-resolution imaging spectroscopy and wide-band imaging with a field of view of $5^{\prime}{\times}5^{\prime}$, it has large throughput as well as high sensitivity for diffuse light compared with JWST. In order to strengthen advantages of the FPC-S, we propose the studies of probing population III stars by the measurement of cosmic near-infrared background radiation and the star formation history at high redshift by the discoveries of active star-forming galaxies. In addition to the major scientific targets, to survey large area opens a new parameter space to investigate the deep Universe. The good survey capability in the parallel imaging mode allows us to study the rare, bright objects such as quasars, bright star-forming galaxies in the early Universe as a way to understand the formation of the first objects in the Universe, and ultra-cool brown dwarfs. Observations in the warm mission will give us a unique chance to detect high-z supernovae, ices in young stellar objects (YSOs) even with low mass, the $3.3{\mu}$ feature of shocked circumstance in supernova remnants. Here, we report the current status of SPICA/FPC project and its extragalactic sciences.

• Korean Journal of Biological Psychiatry
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• v.27 no.1
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• pp.18-26
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• 2020

Objectives The aim was to find effective vectorization and classification models to predict a psychiatric diagnosis from text-based medical records. Methods Electronic medical records (n = 494) of present illness were collected retrospectively in inpatient admission notes with three diagnoses of major depressive disorder, type 1 bipolar disorder, and schizophrenia. Data were split into 400 training data and 94 independent validation data. Data were vectorized by two different models such as term frequency-inverse document frequency (TF-IDF) and Doc2vec. Machine learning models for classification including stochastic gradient descent, logistic regression, support vector classification, and deep learning (DL) were applied to predict three psychiatric diagnoses. Five-fold cross-validation was used to find an effective model. Metrics such as accuracy, precision, recall, and F1-score were measured for comparison between the models. Results Five-fold cross-validation in training data showed DL model with Doc2vec was the most effective model to predict the diagnosis (accuracy = 0.87, F1-score = 0.87). However, these metrics have been reduced in independent test data set with final working DL models (accuracy = 0.79, F1-score = 0.79), while the model of logistic regression and support vector machine with Doc2vec showed slightly better performance (accuracy = 0.80, F1-score = 0.80) than the DL models with Doc2vec and others with TF-IDF. Conclusions The current results suggest that the vectorization may have more impact on the performance of classification than the machine learning model. However, data set had a number of limitations including small sample size, imbalance among the category, and its generalizability. With this regard, the need for research with multi-sites and large samples is suggested to improve the machine learning models.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.1
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• pp.75-92
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• 2007

2002년 프론티어사업의 일환으로서, 10년간 1200억의 예산으로 미래형 신개념비행체 기술개발사업을 시작한 스마트무인기사업은, $2002{\sim}2003$년 수행한 개념연구를 통해 미래형 신개념 고속 수직이착륙 항공기 개념으로서 틸트로터 개념을 선정하고 이의 개발에 매진하고 있다. 사업단에서는 우선, 항공 선진국에서 지난 반세기 동안 시행한 다양한 비행체 개념연구결과에 대해 자체적인 비교 분석 및 국제공동 연구를 근간으로하여, 당시 틸트로터에 필적하는 가능성을 보였던 스탑트로터(보잉사), 복합자이로콥터(카터콥터사) 개념이 아닌, 틸트로터 비행체의 기술개발을 결정하게 되었다. 각각의 비행체 개념이 갖는 위험성과 도전성, 그리고 소요기술, 설계특성, 개발 위험도 등에 대한 면밀한 분석을 기초로 한 사업단의 체계적 의사결정은 주효했다. 스탑트로터개념은 비행시험의 잇단 실패와 지연/잠정 중단사태가 이어졌고, 복합자이로콥터 또한 잇단 비행사고로 2002년 기록한 148kts를 능가하는 고속성능 시현에 지금까지 실패함으로써, 실용화 가능한 고속수직이착륙기로서의 검증을 위해서는 해결해야할 기술적 과제가 많이 남아있음을 보여주고 있다. 반면, 틸트로터 개념의 경우 V-22의 설계 수정형에 대한 성공적인 비행시험완료 및 인증획득으로 전면양산승인이 2005년 결정되어 458대가 (미해병대(360), 해군(48), 공군(50)) 납품될 예정이고, 2010년 인증획득을 목표로 민수용으로 개발중인 BA609의 순조로운 비행시험진행, 무인기로 개발된 Eagle Eye 기술시현기의 비행 시험성공과 2003년 미 해양경찰청으로부터 Deep Water 프로그램의 장거리 순찰임무 주력기종 선정과 같이 군용, 상용, 무인용 고속 수직이착륙 시장의 전 방위적 진입이 현실화되고 있다. 이에 따라 항공업계의 반응은 2가지 방향으로 나뉘고 있다. 하나는 유럽의 ERICA 프로그램과 같이 틸트로터 기술 개발을 서두르자고 주장하는 방향이고, 다른 하나는 시콜스키의 X2 프로그램과 같이 틸트로터와는 차별화된 독자적인 고속 수 직이착륙 비행체 개념 개발을 시도하는 것이다. 이러한 배경으로 국내 독자적인 기술력으로 지난해까지 일구어낸 성공적인 스마트무인기 상세설계 종료 및 축소형 비행체 전환비행성공은 그 의의가 매우 크다고 할 수 있다. 본 논문은 틸트로터 개발사를 통해, 신개념 비행체 개발의 어려움과 교훈을 알아보고, 세계에서 2번째로 틸트로터 기술을 개발하고 있는 스마트무인기 사업의 현황과 기술적 특징 및 의의의 정리, 그리고 틸트로터의 대안으로 진행중인 새로운 고속 VTOL 비행체 연구현황에 대한 소개 와 간단한 기술적 평가를 포함시켰다.

• Journal of The Korean Association For Science Education
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• v.37 no.4
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• pp.637-650
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• 2017

It is necessary for undergraduate students whose citizenship reaches a maturity stage to recognize the importance of citizen participation in social issues related to science and technology and to be able to make meaningful use of citizens' rights and responsibilities. Therefore, in order to understand the actual status of undergraduate students' perceptions and practice capacity for citizen participation in science and technology, university students were selected from the department of arts physical studies (33 cases), humanities social studies (62 cases), and science engineering studies (67 cases) at D university in Gyeonggi province. Then, we investigated the scientific technology and society's interaction oriented by citizen participation, responsible decision-making ability, and the effectiveness of the social issue by scientific technology. Analyses of the results reveal that the overall perception level of the students about the interaction between scientific technology and society was high according to department of the arts physical studies, humanities social studies, science engineering studies, in that order, but the scores were not all in average. Therefore, it was found that the current undergraduate students lacked a deep understanding of the interaction between scientific technology and society regardless of the major field. In addition, the students' perception on citizen participation in the interaction between scientific technology and society was found to be problematic regardless of the major field. In responsible decision-making ability, undergraduate students were found to have difficulties in selecting the best alternative in terms of individual beliefs and welfare of others and formulating the action strategies. In addition, the self-confidence of the students about knowledge, skill, and capacity for action related science and technology in the effectiveness of the social issue by scientific technology was very low regardless of major field. We discussed educational implications of these findings.

• Journal of Korean Society of Archives and Records Management
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• v.20 no.2
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• pp.67-83
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• 2020

Many local governments in Korea provide online services for people to easily access the audio-visual archives of events occurring in the area. However, the current method of managing these archives of the local governments has several problems in terms of compatibility with other organizations and convenience for searching of the archives because of the lack of standard metadata and the low utilization of image information. To solve these problems, we propose the metadata design and machine learning-based automatic indexing technology for the efficient management of the image archives of local governments in Korea. Moreover, we design metadata items specialized for the image archives of local governments to improve the compatibility and include the elements that can represent the basic information and characteristics of images into the metadata items, enabling efficient management. In addition, the text and objects in images, which include pieces of information that reflect events and categories, are automatically indexed based on the machine learning technology, enhancing users' search convenience. Lastly, we developed the program that automatically extracts text and objects from image archives using the proposed method, and stores the extracted contents and basic information in the metadata items we designed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.212-218
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• 2020

When Radiofrequency energy is applied to the human body, the vibration width is very short. Therefore, the electrolyte burn generated when using the direct current does not occur. Ion molecules, polarized molecules, etc., vibrate more than 40,000 times per second, converting them into frictional heat to generate deep heat. The blood flow of capillaries increases 4-5 times more than at rest, increasing the supply of oxygen, nutrients, antibodies, and white blood cells. In addition, the electrochemical reaction does not occur because the vibration width and the pulsation period are very short. It is a physical factor treatment method that does not stimulate the sensory nerves and motor nerves. In this study, an isotonic exercise is performed in a young normal adult using a Radiofrequency pain treatment device. The purpose of this study is to integrate rehabilitation therapy by measuring electromyography data during isotonic exercise and confirming the effect on changes in motor neuron response. The EMG data generated when isotonic exercise of the forearm biceps muscle and the EMG data measured after the use of a Radiofrequency pain treatment device after exercise were RMS, respectively, and verified through t-test. It was confirmed that there was a significant difference in both men and women because the t-value was smaller than the significance level p (<.05).

• Korean Journal of Comparative Education
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• v.24 no.5
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• pp.71-95
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• 2014

This is a pilot study of multifaceted longitudinal research project to explore educational experiences of students with multicultural family backgrounds in Korea. Especially for this pilot study, I selected three foreign-born immigrant youths and tried to explore how these youths describe constraints of their learning experience in different culture. The data for this study were mainly collected through qualitative research methods. For a better understanding of the research participants' perceptions in this study, narrative inquiry and series of semi-structured in-depth interviews were conducted for a period of four months which corresponds to one semester of school system in Korea. As a result, this study found that there is an urgent need to establish a systemic and developmentaly appropriate language education programs that ensure educating the language to the foreign-born immigrant youths because their academic achievement, interpersonal relationships, and future depend greatly on the fluency of Korean language. It was also found that it is necessary to take appropriate educational actions in supporting alternative schools where the foreign-born immigrant youths can fully and seriously considered as a whole person. Although this study has some limitations in examining every single aspect of the current state of education of students with multicultural backgrounds in Korea, it provides deep insight into some of their initial educational experiences and proposes several ways to improve these educational programs for them.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.165-172
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• 2020

In this paper we propose an uses on-device-based edge computing technology and big data analysis methods through the use of on-device-based edge computing technology and analysis of big data, which are distributed computing paradigms that introduce computations and storage devices where necessary to solve problems such as transmission delays that occur when data is transmitted to central centers and processed in current general smart factories. However, even if edge computing-based technology is applied in practice, the increase in devices on the network edge will result in large amounts of data being transferred to the data center, resulting in the network band reaching its limits, which, despite the improvement of network technology, does not guarantee acceptable transfer speeds and response times, which are critical requirements for many applications. It provides the basis for developing into an AI-based facility prediction conservation analysis tool that can apply deep learning suitable for big data in the future by supporting intelligent facility management that can support productivity growth through research that can be applied to the field of facility preservation and smart factory industry with integrated hardware technology that can accommodate these requirements and factory management and control technology.

• Nuclear Engineering and Technology
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• v.18 no.4
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• pp.273-280
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• 1986

The purpose of this study is to obtain the experimental data of the forced flow dryout heat flux in a heat generating debris bed which simulates the degraded nuclear reactor core after severe accident. An experimental investigation has been conducted of dryout heat flux in an inductively heated bed of steel particles with upward forced flow rising coolant circulation system under atmospheric pressure. The present observations were mainly focused on the effects of coolant mass flux, particle size, bed height, and coolant subcooling on the dryout heat flux The data were obtained when carbon steel particles in the size distribution 1.5, 2.5, 3.0 and 4.0 mm were placed in a 55 mm ID Pyrex glass column and inductively heated by passing radio frequency current through a multiturn work coil encircling the column. Distilled water was supplied with variation of mass flux from 0 to 3.5 kg/$\textrm{cm}^2$ s as a coolant in the tests, while the bed height was selected as 55 mm and 110 mm. Inlet temperature of coolant varied by 2$0^{\circ}C$ and 8$0^{\circ}C$. The principal results of the tests are: (1) Dryout heat flux increases with increase of upward forcing mass flux and particle size; (2) The dryout heat flux at the zero mass flux obviously depends on the Particle size as Previous studies; (3) The forced flow dryout heat flux in the shallow bed is somewhat higher than that in the deep bed,