A Study on Bias Effect on Model Selection Criteria in Graphical Lasso

Young-Geun Choi,Seyoung Jeong,유동현 계명대학교 자연과학연구소 2018 Quantitative Bio-Science Vol.37 No.2

Graphical lasso is one of the most popular methods to estimate a sparse precision matrix, which is an inverse of a covariance matrix. The objective function of graphical lasso imposes an 1 A study on Bias Effect on Model Selection Criteria in Graphical Lasso Young-Geun Choi1, Seyoung Jeong2, Donghyeon Yu2* 1SK Telecom, Seoul 04539, Korea 2Department of Statistics, Inha University, Incheon 22212, Korea (Received Oct 8, 2018; Revised Nov 4, 2018; Accepted Nov 12, 2018) Abstract Graphical lasso is one of the most popular methods to estimate a sparse precision matrix, which is an inverse of a covariance matrix. The objective function of graphical lasso imposes an ℓ-penalty on the (vectorized) precision matrix, where a tuning parameter controls the strength of the penalization. The selection of the tuning parameter is practically and theoretically important since the performance of the estimation depends on an appropriate choice of tuning parameter. While information criteria (e.g. AIC, BIC, or extended BIC) have been widely used, they require an asymptotically unbiased estimator to select optimal tuning parameter. Thus, the biasedness of the ℓ- regularized estimate in the graphical lasso may lead to a suboptimal tuning. In this paper, we propose a two-staged bias-correction procedure for the graphical lasso, where the first stage runs the usual graphical lasso and the second stage reruns the procedure with an additional constraint that zero estimates at the first stage remain zero

한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

蕭綱 詩의 形成背景 硏究

鄭根姬 한국중국문화학회 2000 中國學論叢 Vol.9 No.-

本文主旨在于探討梁代宮□詩人蕭綱詩的形成背景. 主要論述齊梁宮□詩的政治 ? 社會和文學背景以及詩人在此發展中的作用. 宮□詩在齊梁文學史上具有代表性, 後成爲唐代近□詩發展的基礎. 梁代有了自我意識的覺醒, 對美的新追求, 玄學的興趣, 經過新變的文學發展, 南朝民歌的盛行, 帝王中心的文學交遊, 都使得文學得以繁榮, 其中帝王的影響起着巨大的作用. 蕭綱是第二代蕭氏王朝的統治者. 在梁代的文學環境中, 澤受了尊師徐□的影響而後確立了他的文學觀. 以蕭綱爲首的東宮中心文學集團推動了宮□詩的發展. 宮□詩吸取六朝各詩派之藝術技巧, 故得以躍爲梁詩壇之主流. 宮□詩具有自己的特殊風格, 特有的文學價値和意義.

[논문]풍쇄전로슬래그의 연직배수재 활용성에 관한 실험적 연구

권정근,임종철 釜山大學校生産技術硏究所 2008 生産技術硏究所論文集 Vol.67 No.-

풍쇄전로슬래그로 천연골재를 대체할 수 있을지에 대한 가능성 여부를 판단하기 위해서는 현장시험에서의 그 효과를 확인하는 것이 가장 중요하다. 이를 위해서는 현장 적용에 앞서 실제 적용 시 발생할 가능성 있는 문제점 들을 인지하고,그들에 대한 대책을 세우는 것이 바람직하다. 여러 문제점들에 대한 다양한 조건들을 우선적으로 실내에서 실내모형실험을 실시하고 이들 문제점들에 대한 해결책을 확보한 후 실제에 적용하는 것이 합리적이며,경제적인 접근방법이라고 볼 수 있다. 따라서,본 연구에서는 실내모형실험을 실시하여 풍쇄전로슬래그를 Sand Drain 또는 Pack Drain에 대용할 경우 발생할 수 있는 문제점을 현장 시험시공 전에 파악하였고,더욱 완성도 높은 현장시험을 할 수 있도록 하였다. 또한,실내모형실험의 결과분석을 통해 연직배수재로서의 이용가능성이 높다고 판단되어 현장시험시공을 실시하였으며,개량사 대체 재료로서의 검증을 실시 · 분석하였다.

敎育大學 實科 實驗實習의 效率化를 위한 資料開發 硏究

鄭原圭,尙貞基,鄭模根,李時元 釜山敎育大學 1987 부산교육대학 논문집 Vol.23 No.1

This study is to research the better ways of management in the practical arts-education in primary schools. The primary school teachers' concrete experiences are made use of to improve their teaching methods in teachers college, a teacher training institute. Therefore this research is supposed to be able to fix on the aim of practical arts-education. Accordingly the questionaires of the problems caused on the scene of education are given to the present teachers in the seasonal system of Pusan Teachers College and Jinju Teachers College. The aim of this research is to develop the materials to improve the educational effectiveness in the practical art-education of teachers college. The result is as follows : 1. According to the questionaires, the problems in the education of the practical course for elementry schools are mainly due to the deficiency of its materials. On the other hand, the teaching methods depending on experiment and practice together should be applied to the class. 2. In the current practical textbook, experiment, practice and observation are shown in the units separately in the contents. The Fifth Educational Revised Plan compared to the current educational curriculum, the units of computer and life are newly showed in the life function scope of the sixth grade textbook. Besides the contents of teaching and the factors of teaching are revised a little. The current educational curriculum, therefore, should be supplied more faithfully. 3. In order to develop the textbook of the practical arts-education of the teachers college, the contents of practical arts-education textbook mainly by experiment and practice are made up of the five scopes of the departments of agriculture, commerce, fishing, household management, etc... 4. To get rid of the formal procedures of abstraction and theory, the practical arts-education of the teachers college quickly needs to make the practical application of audiovisual aids and to introduce the manufactured mechanical apparatus helpful to developing the practical materials by itself. 5. At the departments of practical arts-education of the nation-wide Teachers Colleges, the facilities and equipments of experiment and practice are now as follows : The Ministry of Education shows the standard of equipments, that is, the 7 kinds of laboratories and 179 kinds of experimental apparatus, but the average rates of laboratories of 11 Teachers Colleges is 10.37 percent. So the Ministry of Education should reconsider the standard of its equipments. 6. To develop the practical arts-education of the teachers college, the general institute of practical arts-education should be set up. The kinds of laboratory and its structure (or scale) are shown on each scope.

蕭綱의 文學的 生涯 考察

鄭根姬 한국중국문화학회 1998 中國學論叢 Vol.7 No.-

本文考察了梁代宮體詩人蕭綱的文學生平. 主旨在于是論述齊梁宮體詩人蕭綱的文學生涯以及詩人文學作品在此發展中的作用. 宮體詩在齊梁文學史上具有代表性, 後展成爲唐代近體詩的根源. 梁代有了活潑的文學交遊, 文學也卽得以繁榮, 其中帝王的影響其着巨大的作用. 蕭綱是第二代蕭氏王朝的統治者. 在梁代的文學環境中, 澤受了尊師徐리的影響而後確立了他的文學觀. 以蕭綱爲首的東宮中心文學集團得到地推動宮體詩的發展.

랫드에서 법제유황과 비법제유황의 독성비교

김근수, 정유리, 이남진, 홍성희, 유종훈, 정재황, 강종구 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.2

본문참고

簫綱 樂府詩 小考

鄭根姬 한국중국문화학회 1999 中國學論叢 Vol.8 No.-

本論文的硏究目的主要是在探索蕭綱樂府詩的文學特質, 題材與表現技巧, 進而評定蕭綱樂府詩在文學史上的美學價値. 本論文以梁代宮體詩人蕭綱的樂府詩八十七首爲硏究對象. 在二百八十五首蕭綱宮體詩中, 樂府詩一介흔重要的體裁. 主旨在于是論述蕭綱樂府詩的題材, 形式以及表現上的特徵. 蕭綱樂府詩題材是艶情o日常o邊塞o詠物o遊仙, 其中艶情詩最多. 艶情詩的所謂情, 主要詩女性的心理活動. 詩題大部分是曲o行o篇o歌, 詩形最多占有五言八句, 五言四句. 樂府詩里用華麗的文辭, 出現多種的女性形象, 知道了當時女性的生活環境.

양측성 전정장애 환자들의 전정기능검사

이근호,김재일,정필섭,전범석,이광우 대한신경과학회 1996 대한신경과학회지 Vol.14 No.4

[논문]억지말뚝을 이용한 자립식 흙막이 공법의 해석기법 개발

권정근,임종철,김창영 釜山大學校生産技術硏究所 2008 生産技術硏究所論文集 Vol.67 No.-

억지말뚝을 이용한 자립식 흙막이 공법은 많은 실험과 현장적용을 통해 경제적이며 효율적인 공법으로 입증되었다(김,2006). 그러나 지반공학적인 이론적 확립이 되어 있지 않았다. 이에 이론적인 해석기법의 개발을 위해 실제 시공여건을 반영한 단계굴착을 통한 실내모형실험이 수행되었다. 본 연구에서는 단계굴착에 따른 흙막이 벽체 및 억지말뚝의 거동과,단계굴착에 따른 흙막이 벽체와 억지말뚝에 작용하는 토압과 응력을 분석하였다. 그 결과를 바탕으로 지반의 파괴 메카니즘을 제안하였으며 연결부,엄지말뚝,억지말뚝의 해석기법을 개발하였다.