유우(乳牛)의 Trypanosoma에 관(關)한 조사(調査)

김창기,Kim, Chang Ki 대한수의학회 1974 大韓獸醫學會誌 Vol.14 No.2

1. The length of Trypanossoma was $20{\sim}40{\mu}m$ (including flagellum) in dairy cattle in Korea, 2. Crithidia of Trypanosoma was found out in the head of depressed Tabanid fly and 77% in the flies. 3. The Trypanosoma in the tryptose blood agar was changed its form from 6 weeks after cultivation. 4. Infectious rate of Trypanosoma in dairy cattle was the same as in Korean cattle. 5. Infectious rate of Trypanosoma in dairy cattle was higher in summer than in winter. 6. No Trypanosoma was found in the blood from the jugular vein of calves born in winter. 7. Erythrocyte increased while leukocyte decreased in nummber in the blood of the cattle infected with Trypanosoma.

계(鷄)의 거세(去勢)에 관(關)한 연구(硏究) 제(第)1보(報) 부분거세(部分去勢) 및 Diethylstilbestrol이 계추(鷄雛)에 미치는 영향(影響)

김창기,Kim, Chang Ki 대한수의학회 1974 大韓獸醫學會誌 Vol.14 No.2

This experiment was carried out for 42 days to investigate the effect of caponizing and diethylstilbestrol (DES) on body weight gain, rate of feed conversion, weight of carcass and percentage of dressing in young chickens. The chickens used were 128 male Hamphorn of 30 days old. In the body weight gain of chickens, control group was higher than the other groups (P<0.01); $T_1$ group was the lowest group. Rate of feed conversion of control group was higher than $T_2$ and $T_3$ groups.

댓글 분석을 통한 19대 한국 대선 후보 이슈 파악 및 득표율 예측

서대호(Dae-Ho Seo),김지호(Ji-Ho Kim),김창기(Chang-Ki Kim) 한국지능정보시스템학회 2018 지능정보연구 Vol.24 No.3

인터넷의 일상화와 각종 스마트 기기의 보급으로 이용자들로 하여금 실시간 의사소통이 가능하게 하여 기존의 커뮤니케이션 양식이 새롭게 변화되었다. 인터넷을 통한 정보주체의 변화로 인해 데이터는 더욱 방대해져서 빅데이터라 불리는 정보의 초대형화를 야기하였다. 이러한 빅데이터는 사회적 실제를 이해하기 위한 새로운 기회로 여겨지고 있다. 특히 텍스트 마이닝은 비정형 텍스트 데이터를 이용해 패턴을 탐구하여 의미있는 정보를 찾아낸다. 텍스트 데이터는 신문, 도서, 웹, SNS 등 다양한 곳에 존재하기 때문에 데이터의 양이 매우 다양하고 방대하여 사회적 실제를 이해하기 위한 데이터로 적합하다. 본 연구는 한국 최대 인터넷 포털사이트 뉴스의 댓글을 수집하여 2017년 19대 한국 대선을 대상으로 연구를 수행하였다. 대선 선거일 직전 여론조사 공표 금지기간이 포함된 2017년 4월 29일부터 2017년 5월 7일까지 226,447건의 댓글을 수집하여 빈도분석, 연관감성어 분석, 토픽 감성 분석, 후보자 득표율 예측을 수행하였다. 이를 통해 각 후보자들에 대한 이슈를 분석 및 해석하고 득표율을 예측하였다. 분석 결과 뉴스 댓글이 대선 후보들에 대한 이슈를 추적하고 득표율을 예측하기에 효과적인 도구임을 보여주었다. 대선 후보자들은 사회적 여론을 객관적으로 판단하여 선거유세 전략에 반영할 수 있고 유권자들은 각 후보자들에 대한 이슈를 파악하여 투표시 참조할 수 있다. 또한 후보자들이 빅데이터 분석을 참조하여 선거캠페인을 벌인다면 국민들은 자신들이 원하는 바가 후보자들에게 피력, 반영된다는 것을 인지하고 웹상에서 더욱 적극적인 활동을 할 것이다. 이는 국민의 정치 참여 행위로써 사회적 의의가 있다. With the everyday use of the Internet and the spread of various smart devices, users have been able to communicate in real time and the existing communication style has changed. Due to the change of the information subject by the Internet, data became more massive and caused the very large information called big data. These Big Data are seen as a new opportunity to understand social issues. In particular, text mining explores patterns using unstructured text data to find meaningful information. Since text data exists in various places such as newspaper, book, and web, the amount of data is very diverse and large, so it is suitable for understanding social reality. In recent years, there has been an increasing number of attempts to analyze texts from web such as SNS and blogs where the public can communicate freely. It is recognized as a useful method to grasp public opinion immediately so it can be used for political, social and cultural issue research. Text mining has received much attention in order to investigate the public`s reputation for candidates, and to predict the voting rate instead of the polling. This is because many people question the credibility of the survey. Also, People tend to refuse or reveal their real intention when they are asked to respond to the poll. This study collected comments from the largest Internet portal site in Korea and conducted research on the 19th Korean presidential election in 2017. We collected 226,447 comments from April 29, 2017 to May 7, 2017, which includes the prohibition period of public opinion polls just prior to the presidential election day. We analyzed frequencies, associative emotional words, topic emotions, and candidate voting rates. By frequency analysis, we identified the words that are the most important issues per day. Particularly, according to the result of the presidential debate, it was seen that the candidate who became an issue was located at the top of the frequency analysis. By the analysis of associative emotional words, we were able to identify issues most relevant to each candidate. The topic emotion analysis was used to identify each candidate`s topic and to express the emotions of the public on the topics. Finally, we estimated the voting rate by combining the volume of comments and sentiment score. By doing above, we explored the issues for each candidate and predicted the voting rate. The analysis showed that news comments is an effective tool for tracking the issue of presidential candidates and for predicting the voting rate. Particularly, this study showed issues per day and quantitative index for sentiment. Also it predicted voting rate for each candidate and precisely matched the ranking of the top five candidates. Each candidate will be able to objectively grasp public opinion and reflect it to the election strategy. Candidates can use positive issues more actively on election strategies, and try to correct negative issues. Particularly, candidates should be aware that they can get severe damage to their reputation if they face a moral problem. Voters can objectively look at issues and public opinion about each candidate and make more informed decisions when voting. If they refer to the results of this study before voting, they will be able to see the opinions of the public from the Big Data, and vote for a candidate with a more objective perspective. If the candidates have a campaign with reference to Big Data Analysis, the public will be more active on the web, recognizing that their wants are being reflected. The way of expressing their political views can be done in various web places. This can contribute to the act of political participation by the people.

재생에너지 발전량 예측제도를 위한 수치기상예측 모델링 검증

김창기(Chang Ki Kim),김현구(Hyun-Goo Kim),강용혁(Yong-Heack Kang),윤창열(Chang-Yeol Yun),김보영(Boyoung Kim),김진영(Jinyoung Kim),오명찬(Myung Chan Oh) 한국태양에너지학회 2021 한국태양에너지학회 학술대회논문집 Vol.2021 No.11

ERP 도입 후 사용자 만족도 향상을 위한 변화관리 모형에 관한 연구: A사 사례를 중심으로

신현식 ( Hyun Sik Shin ),송용욱 ( Yong Uk Song ),김창기 ( Chang Ki Kim ) 한국정보시스템학회 2010 情報시스템硏究 Vol.19 No.2

This article identifies factors affecting successful ERP systems by focusing on the stages after stabilizing ERP systems and overcoming temporary performance dip by introduction of ERP systems, and suggests change management tactics to control those identified factors. We can not expect that every users are familiar with the usage of an ERP system even after they are informed about the expected advantage of the newly implemented ERP system and trained intensively for changed business process and system usage while implementing a new ERP system. Moreover, even after more than six months usage of the system, the users may still have some trouble due to the reason why they have insufficient information about the expected advantage of the system (recognition gap) and insufficient knowledge about the changed usage of the system (knowledge gap). Hence, this article diagnoses by conducting a case study that those recognition and knowledge gap would have a severe bad influence upon the users` trust and satisfaction on ERP systems. This article suggests an appropriate change management tactics to overcome those recognition and knowledge gap by considering the relationship with the efforts for change management before, during, and after the introduction of ERP systems and performing an in-depth analysis on the users` dissatisfaction and request for update during the stages after the stabilization of the ERP systems. This article also shows a corroborative evidence that these efforts of change management consequently contributes to the solution of users` distrust and dissatisfaction. In sum, this article identifies the factors influencing badly on the magnitude and seriousness of knowledge and recognition gap, and suggests a conceptual research model which says that the satisfaction of ERP users could be uplifted by the solution of their knowledge and recognition gap if we keep making efforts on appropriate change management considering those identified factors during the stages after the stabilization of an ERP system.

A Study on standardization of DNI derived from COMS satellite

Chang Ki Kim(김창기),Yong-Heack Kang(강용혁),Hyungoo Kim(김현구),Shin-Young Kim(김신영),Chang-Yeol Yun(윤창열),Jinyoung Kim(김진영) 한국신재생에너지학회 2017 한국신재생에너지학회 학술대회논문집 Vol.2017 No.9

제주지역 출력제한 해결을 위한 태양광 예보 기술 개발

김창기(Chang Ki Kim),김현구(Hyun-Goo Kim),강용혁(Yong-Heack Kang),김진영(Jinyoung Kim),김병기(Byung-Ki Kim) 한국태양에너지학회 2023 한국태양에너지학회 학술대회논문집 Vol.2023 No.4

전자계 결합특성 및 대류 경계조건을 적용한 수치 해석적 열전달 해석

김창기(Kim, Chang-Ki),김상훈(Kim, Shang-Hoon),정상용(Jung, Sang-Yong) 한국전기전자학회 2009 전기전자학회논문지 Vol.13 No.3

본 논문에서는 정열계 해석을 위해 유한요소법(F.E.M)을 이용한 열전달 해석 기법에 대하여 다루고 있다. 특히, 열전달의 주요 쟁점인 혼합 경계조건을 띄는 대류 경계조건을 자계 문제와 비교하여 갤러킨법(Galerkin Method)으로 정식화하였다. 그리고 해의 신뢰성을 확보하기 위해 자계 해석을 통해 열원이 되는 손실을 구한 후, 반복적 알고리즘을 통해 에너지 평형 방정식을 만족하는 열전달 계수를 산정하여 열전달 문제를 고려하는 자계-열계 결합 해석을 하였다. 마지막으로, 측정치와 비교하여 제안된 방법의 효용성을 증명하였다. The heat transfer analysis applying finite element method has been carried out. Particularly, the convection boundary condition associated with the mixed boundary condition is numerically formulated by the Galerkin method analogous to the magnetic field problem. Also, the coupled electromagnet-thermal field analysis by the proposed heat transfer coefficient computation algorithm is executed to enhance the accuracy of solutions. Finally, the validity of the proposed results is verified by comparison with the measured ones.

공공데이터포털에 등재된 천리안 1호 위성영상 기반 일사량의 검증 및 관측 일사량의 한계점

김창기(Kim Chang Ki),김현구(Kim Hyun-Goo),강용혁(Kang Yong-Heack),김보영(Kim Bo-Young) 한국태양에너지학회 2020 한국태양에너지학회 논문집 Vol.40 No.6

Recently, satellite-derived solar irradiance data, generated by the Korea Institute of Energy Research, has been opened for public use via the Public Big Data Platform organized by the Ministry of Public Administration and Security. These data are the monthly mean of daily total irradiance for the domain with latitude between 32°N and 40°N and longitude between 124°E and 130°E with a horizontal resolution of 1 km. The purpose of this study is to evaluate the monthly mean of daily total irradiance by comparing it with the ground truth obtained from the Automated Synoptic Observing System (ASOS) in the Korea Meteorological Administration (KMA). For the investigation period, that is, from 2012 to 2019, the average value of the correlation coefficients for all stations is 0.913. In addition, the root mean square error, which is normalized to the observation, is 12.2%, which is larger than that reported in previous studies. The ground observations employed for the evaluation were not performed by data quality control system. In the Daejeon station, in-situ observation from ASOS in KMA is significantly different from the measurement that is controlled by a data quality system, which means that in-situ observation from ASOS in KMA would be dangerous for use in the evaluation. With the solar irradiance controlled by the data quality control system, the root mean square error is reduced from 15.8% to 5.3%. Therefore, it is necessary to examine the in-situ observation via data quality control for the quantitative analysis of satellite-derived solar irradiance.

가우시안 거리 가중치를 이용한 Exemplar-based Inpainting

김창기(Chang-Ki Kim),김백섭(Baek-Sop Kim) 한국정보과학회 2009 한국정보과학회 학술발표논문집 Vol.36 No.2C

디지털 영상에서 Image inpainting 기법은 다양한 원인에 의한 영상 훼손이나 제거된 물체를 복원하는 기술을 말한다. 이러한 Inpainting 기법은 편미분 방정식(PDE)을 이용한 방법, 텍스처 병합 기반의 방법들로 나눌 수 있다. 또한 동영상과 단일 정지영상에 따라 그 처리 방법이 달라진다. 기존의 텍스처 병합기반의 방법은 주변 화소(Pixel)를 평활화(Smoothing) 처리를 통해 blur 되어 보이던 단점을 보안한 반면 훼손 또는 제거된 물체가 큰 경우 훼손 영역이 어색하게 복원되는 문제점이 있다. 따라서 본 연구는 단일 정지영상에서 훼손 영역이 크더라도 보다 자연스럽게 복원 될 수 있는 방법을 제안한다.