표면 연마 방법에 따른 니티놀 잔류응력 분석

정지선,홍광표,김운용,조명우,Jeong, Ji-Seon,Hong, Kwang-Pyo,Kim, Woon-yong,Cho, Myeong-Woo 한국금형공학회 2017 한국금형공학회지 Vol.11 No.2

Nitinol, a shape memory alloy (SMA), is manufactured from titanium and nickel and it used in various fields such as electrical applications, micro sensors. It is also recommended as a material in medical for implant because it has excellent organic compatibility. Nitinol is intended to be inserted into the human body, products require a high-quality surface and low residual stress. To overcome this problems, explore electrolyte polishing (EP) is being explored that may be appropriate for use with nitinol. EP is a particularly useful machining method because, as a non contact machining method, it produces neither machining heat nor internal stress in the machined materials. Sandpaper polishing is also useful machining method because, as a contact machining method, it can easily good surface roughness in the machined materials. The electrolyte polishing (EP) process has an effect of improving the surface roughness as well as the film polishing process, but has a characteristic that the residual stress is hardly generated because the work hardened layer is not formed on the processed surface. The sandpaper polishing process has the effect of improving the surface roughness but the residual stress remains in the surface. We experimented with three conditions of polishing process. First condition is the conventional polishing. Second condition is the electrochemical polishing(EP). And Last condition is a mixing process with the conventional polishing and the EP. Surface roughness and residual stress of the nitinol before a polishing process were $0.474{\mu}mRa$, -45.38MPa. Surface roughness and residual stress of the nitinol after mixing process of the conventional polishing and the EP were $1.071{\mu}mRa$, -143.157MPa. Surface roughness and residual stress of the nitinol after conventional polishing were $0.385{\mu}mRa$ and -205.15MPa. Surface roughness and residual stress of sandpaper and EP nitinol were $1.071{\mu}mRa$, -143.157MPa. The result shows that the EP process is a residual stress free process that eliminates the residual stress on the surface while eliminating the deformed layer remaining on the surface through composite surface machining rather than single surface machining. The EP process can be used for biomaterials such as nitinol and be applied to polishing of wafers and various fields.

온라인 언급이 기업 성과에 미치는 영향 분석

정지선(Ji Seon Jeong),김동성(Dong Sung Kim),김종우(Jong Woo Kim) 한국지능정보시스템학회 2015 지능정보연구 Vol.21 No.4

인터넷 기술의 발전과 인터넷 상 데이터의 급속한 증가로 인해 데이터의 활용 목적에 적합한 분석방안 연구들이 활발히 진행되고 있다. 최근에는 텍스트 마이닝 기법의 활용에 대한 연구들이 이루어지고 있으며, 특히 문서 내 텍스트를 기반으로 문장이나 어휘의 긍정, 부정과 같은 극성 분포에 따라 의견을 스코어링(scoring)하는 감성분석과 관련된 연구들도 다수 이루어지고 있다. 이러한 연구의 연장선상에서, 본 연구는 인터넷 상의 특정 기업에 대한 뉴스 데이터를 수집하여 이들의 감성분석을 실시함으로써 주가의 등락에 대한 예측을 시도하였다. 개별 기업의 뉴스 정보는 해당 기업의 주가에 영향을 미치는 요인으로, 적절한 데이터 분석을 통해 주가 변동 예측에 유용하게 활용될 수 있을 것으로 기대된다. 따라서 본 연구에서는 개별 기업의 온라인 뉴스 데이터에 대한 감성분석을 바탕으로 개별 기업의 주가 변화 예측을 꾀하였다. 이를 위해, KOSPI200의 상위 종목들을 분석 대상으로 선정하여 국내 대표적 검색 포털 서비스인 네이버에서 약 2년간 발생된 개별 기업의 뉴스 데이터를 수집 · 분석하였다. 기업별 경영 활동 영역에 따라 기업 온라인 뉴스에 나타나는 어휘의 상이함을 고려하여 각 개별 기업의 어휘사전을 구축하여 분석에 활용함으로써 감성분석의 성능 향상을 도모하였다. 분석결과, 기업별 일간 주가 등락여부에 대한 예측 정확도는 상이했으며 평균적으로 약 56%의 예측률을 보였다. 산업 구분에 따른 주가 예측 정확도를 통하여 ‘에너지/화학’, ‘생활소비재’, ‘경기소비재’의 산업군이 상대적으로 높은 주가 예측 정확도를 보임을 확인하였으며, ‘정보기술’과 ‘조선/운송’ 산업군은 주가 예측 정확도가 낮은 것으로 확인되었다. 본 논문은 온라인 뉴스 정보를 활용한 기업의 어휘사전 구축을 통해 개별 기업의 주가 등락 예측에 대한 분석을 수행하였으며, 향후 감성사전 구축 시 불필요한 어휘가 추가되는 문제점을 보완한 연구 수행을 통하여 주가 예측 정확도를 높이는 방안을 모색할 수 있을 것이다. Due to the development of internet technology and the rapid increase of internet data, various studies are actively conducted on how to use and analyze internet data for various purposes. In particular, in recent years, a number of studies have been performed on the applications of text mining techniques in order to overcome the limitations of the current application of structured data. Especially, there are various studies on sentimental analysis to score opinions based on the distribution of polarity such as positivity or negativity of vocabularies or sentences of the texts in documents. As a part of such studies, this study tries to predict ups and downs of stock prices of companies by performing sentimental analysis on news contexts of the particular companies in the Internet. A variety of news on companies is produced online by different economic agents, and it is diffused quickly and accessed easily in the Internet. So, based on inefficient market hypothesis, we can expect that news information of an individual company can be used to predict the fluctuations of stock prices of the company if we apply proper data analysis techniques. However, as the areas of corporate management activity are different, an analysis considering characteristics of each company is required in the analysis of text data based on machine-learning. In addition, since the news including positive or negative information on certain companies have various impacts on other companies or industry fields, an analysis for the prediction of the stock price of each company is necessary. Therefore, this study attempted to predict changes in the stock prices of the individual companies that applied a sentimental analysis of the online news data. Accordingly, this study chose top company in KOSPI 200 as the subjects of the analysis, and collected and analyzed online news data by each company produced for two years on a representative domestic search portal service, Naver. In addition, considering the differences in the meanings of vocabularies for each of the certain economic subjects, it aims to improve performance by building up a lexicon for each individual company and applying that to an analysis. As a result of the analysis, the accuracy of the prediction by each company are different, and the prediction accurate rate turned out to be 56% on average. Comparing the accuracy of the prediction of stock prices on industry sectors, ‘energy/chemical’, ‘consumer goods for living’ and ‘consumer discretionary’ showed a relatively higher accuracy of the prediction of stock prices than other industries, while it was found that the sectors such as ‘information technology’ and ‘shipbuilding/transportation’ industry had lower accuracy of prediction. The number of the representative companies in each industry collected was five each, so it is somewhat difficult to generalize, but it could be confirmed that there was a difference in the accuracy of the prediction of stock prices depending on industry sectors. In addition, at the individual company level, the companies such as ‘Kangwon Land’, ‘KT & G’ and ‘SK Innovation’ showed a relatively higher prediction accuracy as compared to other companies, while it showed that the companies such as ‘Young Poong’, ‘LG’, ‘Samsung Life Insurance’, and ‘Doosan’ had a low prediction accuracy of less than 50%. In this paper, we performed an analysis of the share price performance relative to the prediction of individual companies through the vocabulary of pre-built company to take advantage of the online news information. In this paper, we aim to improve performance of the stock prices prediction, applying online news information, through the stock price prediction of individual companies. Based on this, in the future, it will be possible to find ways to increase the stock price prediction accuracy by complementing the problem of unnecessary words that are added to the sentiment dictionary.

포스터 제작 협동 활동과 연계한 인성교육 프로그램이 초등학교 통합학급 학생의 인성역량, 장애학생 수용태도 및 친사회성에 미치는 영향

정지선(Jeong Ji Seon),이숙향(Lee Suk Hyang) 한국자폐학회 2020 자폐성 장애연구 Vol.20 No.1

The purpose of this study was to find out the effects of character education program connected with poster production cooperative activities on the character competency, acceptance toward students with disabilities, and pro-social behavior. For this study, 2 students with disabilities and their 51 peers without disabilities(4th and 5th graders) in each inclusive classroom of A elementary school and 2 students with disabilities and their 44 peers without disabilities of B elementary school participated in this study as an experimental and control groups, respectively. This program was conducted twice a week, 20 times for the experimental group and the differences between the two groups were analyzed before and after intervention to find out the effects of this program. The results of analysis were as follows: First, the character competency score of students without disabilities in the experimental group was significantly improved compared with those of the control group and there were positive changes in the character competency score of students with disabilities in the experimental group. Second, acceptance toward students with disabilities was significantly improved in the students without disabilities in the experimental group. Third, there were positive changes in pro-social score of the students with disabilities in the experimental group. Based on the results, limitations and implications for future studies were provided. 본 연구는 포스터 제작 협동 활동과 연계한 인성교육 프로그램이 초등학교 통합학급학생의 인성역량, 장애학생 수용태도 및 친사회성에 미치는 영향에 대하여 알아보았다. 본 연구를 위해 A초등학교 4학년과 5학년에 재학 중인 장애학생 2명과 그들이 속해있는 각 통합학급 비장애학생 51명이 실험집단으로, B초등학교 4학년과 5학년에 재학 중인 장애학생과 그들이 속해 있는 각 통합학급 비장애학생 44명이 통제집단으로 각각 참여하였다. 실험집단 학생들에게 포스터 제작 협동 활동과 연계한 인성교육 프로그램을 주 2회씩 총 20회기 실시하였으며 본 프로그램의 효과를 조사하기 위해 중재 전·후의 두 집단 간 차이를 분석하였다. 그 결과 첫째, 실험집단 비장애학생의 인성역량이 통제집단에 비해 유의하게 향상되었으며, 실험집단 장애학생의 인성역량에도 긍정적인 변화가 나타났다. 둘째, 실험집단 비장애학생의 장애학생 수용태도가 통제집단에 비해 유의하게 향상되었다. 셋째, 실험집단 장애학생의 친사회성 점수에도 긍정적인 변화가 나타났다. 이러한 결과를 토대로 포스터 제작 협동 활동과 연계한 인성교육 프로그램의 긍정적인 영향과 관련된 요인과 의의를 살펴보고 후속연구에 대해 제언하였다.

개복 담낭절제술 후 오랜 기간 후에 발생한 혈액 담즙증

정지선 ( Jee Sun Jeong ),음영욱 ( Young Ook Eum ),장지혜 ( Ji Hye Jang ),정은 ( Eun Chung ),양현 ( Hyun Yang ),김현선 ( Hyun Seon Kim ),배일헌 ( Il Hun Bae ),박선미 ( Seon Mee Park ) 대한췌장담도학회 2014 대한췌담도학회지 Vol.19 No.1

A 77-year-old woman was admitted with 5 days history of melena. She had an open cholecystectomy 30 years ago. Abdominal computed tomography and duodenoscopy revealed massive hemobilia. Angiography showed right hepatic arterial fistula to common bile duct near the surgical clip. Embolization was done successfully and the patient recovered. We experienced a case of a massive hemobilia which was occurred after a long period of time since open cholecystectomy without pseudoaneurysmal change of the right hepatic artery. And we suggest the direct vessel injury and fistula between the bile duct and a blood vessel as a possible cause of hemobilia in this case. Korean J Pancreatobiliary 2014;19(1):42-46

RP-HPLC를 이용한 백소엽(白蘇葉)과 자소엽(紫蘇葉)의 카페익산과 로즈마린산 분석

김병연 ( Byung Youn Kim ),정지선 ( Ji Seon Jeong ),권하정 ( Ha Jeong Kwon ),이제현 ( Je Hyun Lee ),홍선표 ( Seon Pyo Hong ) 대한본초학회 2008 大韓本草學會誌 Vol.23 No.3

RP-HPLC-PAD를 이용한 갈근(葛根)과 갈근(葛根) 함유 처방의 Puerarin과 Daidzin 분석

초진영 ( Chen Ying Chiao ),권하정 ( Ha Jeong Kwon ),정지선 ( Ji Seon Jeong ),이제현 ( Je Hyun Lee ),홍선표 ( Seon Pyo Hong ) 대한본초학회 2008 大韓本草學會誌 Vol.23 No.4

Objectives: This study presents a reversed-phase high-performance liquid chromatography- pulsed amperometric detection (RP-HPLC-PAD) method for the determination of puerarin and daidzin in Puerariae Radix extract and Chinese medicinal preparations. Methods: Chromatographic separation was performed using a 10% acetonitrile with a reversed-phase column (Unison UK-C18, 100 mm×2.0 mm I.D.; 3 μm). The analyses were detected by pulsed amperometric detector (PAD) in alkaline conditions by combining with post-column NaOH solution. Geniposide was used as an internal standard. Results: The limit of detection (S/N=3) and the limit of quantification (S/N=10) were 0.025 ng, 0.075 ng for puerarin, and 0.05 ng, 0.15 ng for daidzin, respectively. The intra- and inter-day precisions (RSDs) were less than 6.5% and average recoveries of puerarin were 99.7-101.3% and those of daidzin were 101.0-102.8%. Conclusions: According to above results, we developed a determination method for puerarin and daidzin in Puerariae Radix with high sensitivity and selectivitely.