• Title/Summary/Keyword: case-control studies

Search Result 1,587, Processing Time 0.026 seconds

A Study on Selecting Geospatial Framework Data Using Factor Analysis (요인분석을 이용한 기본공간정보 선정에 관한 연구)

  • Choe, Byong Nam;Lee, Ji Hun;Park, Jin Sik;Kang, In Gu
    • Spatial Information Research
    • /
    • v.23 no.5
    • /
    • pp.53-64
    • /
    • 2015
  • Several countries have built National Spatial Data Infrastructure (NSDI) for information sharing among various fields. One of the important factors of NSDI is framework data, which is the most commonly used geospatial data across various fields. Previous studies on the framework data suggest components based on frequency survey and case study. However, such research methods do not have objectivity in setting the components of the framework data. This research uses factor analysis with 104 medium-level layers from the most widely used National Base Map and 5 layers from the other sources including cadastre and aerial image. Each layer is scaled with usage level as four different patterns of 1) background data, 2) reference data, 3) base data, and 4) other data, respectively. The analysis results show that the layers are grouped into 5 to 7 factors according to the patterns. ANOVA reveals that the mean differences between the factors with high values and the other factors with low values under each pattern are statistically significant. Such high value factors under each pattern consist of similar layers, close to identical, with those under the other categories. This research proposes framework data system, including transportation, building, hydrography, elevation, administrative district, digital orthoimagery, geodetic control, and cadastral based on the analysis results. Proposed framework in this research will be a basis of establishing spatial data sharing system. For sharing proposed framework data in various fields, these data must be established and distributed as actual standard and also related future researches should be performed.

The Development of a Multi-Purpose Irradiator and the Characteristic of Dose Distribution (다목적 방사선 조사장치 개발 및 선량분포특성)

  • Lee, Dong-Hoon;Ji, Young-Hoon;Lee, Dong-Han;Kim, Yoon-Jong;Hong, Seung-Hong
    • Journal of the Institute of Electronics Engineers of Korea SC
    • /
    • v.39 no.6
    • /
    • pp.42-48
    • /
    • 2002
  • The design, construction and performance test of a convenient multi-purpose irradiator is described. A multi-purpose irradiator using Cesium-137 has been developed for studies of low dose radiation effects in biology and for calibration of Thermo Luminescent dosimeter(TLD). During the operation, three rods of radioactive material which are 10cm in length revolve 180 degrees and irradiate biological samples, or TLD, and return to their shielded position, after the programmed time. A programmable Logic Controller(PLC) controls the sequence of operation, interlock, motor rotation and safety system. The rotation speed of biological samples can vary up to 20 RPM. A real time monitoring system was also incorporated to check and control the operation status of the irradiator. The capacity of the irradiation chamber was 4.5 liters. The isodose distribution at arbitrary vertical planes was measured by using film dosimetry. The dose-rate was 0.13 cGy/min in air and 0.11 cGy/min in water equivalent material in the case of Cesium-137. Range of activity was 2 Ci. The homogeneity of dose distribution in the chamber was ${\pm}$7%. The actual radiation level on the surface was within permissible levels. The irradiator had a maximum 0.35 mR/min radiation leakage on its surface.

The Appropriation of Public Space and Logic of Exclusion: A Case of the Tap-Gol Park from late 1990's to early 2000's (공공 공간의 전유와 배제 논리: 1990년대 후반부터 2000년대 초반까지 탑골공원의 사례)

  • Lee, Kangwon
    • Journal of the Korean Geographical Society
    • /
    • v.48 no.6
    • /
    • pp.944-966
    • /
    • 2013
  • This study attempts to highlight the cultural importance of urban public space by analyzing the changes Tap-Gol Park from late 1990's to early 2000's, a park located in the heart of Seoul, underwent in its meanings and uses. Public space, a product of modern urban planning, is characterized by its openness and accessibility and represents the vitality of modern city, serving as a meeting place for citizens with different social backgrounds at such occasions as gatherings and festivals. While the government or a few dominant groups try to control the public and their behavior in public space by giving a specific meaning to it and specifying its use, people constantly set their foot in it and view the space as a place differently for each individual's personal or social reasons. It is therefore not very surprising that the meaning of public space has never been successfully defined. Following the traces of attempts to define the meaning of public space and considering how public space can be efficiently used will shed light on what types of groups, especially ages and classes participated in the contest for the use of public space and expressed their own cultures in urban society through various negotiations.

  • PDF

The Comparative Study between Korean and Indian Students regarding Relationship among Self-leadership Types, Performance and Class Attendance Attitudes (학습태도를 매개변수로 한 셀프리더십 유형과 학업성과간 관계: 한국과 인도간 비교연구)

  • Park, Ki-Ho;Park, Sang-Hyeok
    • Journal of Digital Convergence
    • /
    • v.9 no.4
    • /
    • pp.253-265
    • /
    • 2011
  • A number of organizations have had big interests in studies concerning leadership and not only academia but also psychological areas do also. Until now, leadership has been accentuated by managers or team leaders especially. Recently, however, the concept of self-leadership directing one's own activities through self-control or self-management is being focused on in practices and in academia. This study is to investigate the influence between self-leadership strategies as predictors and learning performance in IT classes as dependents variables mediated by attitude of attendance focused on the social science students in two universities (Korea(116 samples) and India(36 samples)). And this research tried to compare difference between two university students. As a result of empirical analysis, Korean learners making an effort by themselves show a tendency to think constructively. Namely, even though the level of difficulty may be high, by positive self-talk, respondents usually make an effort to get high academic performance. In case of Indian respondents, students who are in behavior-oriented show higher academic performance. Research results can give us direction of task-taking attitudes in firms or learning attitudes in teaching organizations and implications to human resource managers who are in charge of improving learning performance or productivity.

The Empirical Research on Tax Effect with the Cooperate Conversion of Private Company (개인기업의 법인전환에 따른 세무효익 연구)

  • Lee Jae-Sung;Seo Il
    • Management & Information Systems Review
    • /
    • v.7
    • /
    • pp.401-426
    • /
    • 2001
  • The form of company divides private and coporate companies. In general. private company has direct connection with owner's fortunes. On the contrary, cooperate company is established by a group of people who invest capital funds on their company and has an independent character. In the case of private company, their are many merits that owner can obtain all the benefits without divisions. However, the owner can mix up the control of accounting between public and private matters. As a result confusing, it is difficult to estimate financial situation of company and is limited to fund supply. Futhermore, owner has unlimited liabilities with law credit as a social cognition. Especially, the government tries to induce conversion of private company into cooperation one on the basis of benefits of tax and so on. In those situations, the purpose of this thesis is to study the management benefits with the conversion of private company into cooperate one focucing on the related tax reduction effect. To do this, I have reviewed all of the related textual achievements and tested the real significancy of tax reduction effect of conversion empirically. Finally, I have concluded that the conversion of private company into coporate one has many benefits including significant tax reduction effect. In other side, I have considered and reviewed many difficulties related conversion privated company into cooperate one and suggested some improvements as results. This thesis is comprises 5 chapters as follows; The first chapter explains purposes and methodologies and extents of this study. The second chapter deals the theoretical basis of conversion of private company into cooperate one and cooperates diverse benefits and types and processes of conversion. The preceding research achievements are also reviewed in this chapter. The third chapter deals empirical testing on the real tax reduction effect of the conversion. The analysis is proceeded through t-test of difference of tax between pre and after conversion. The result is presented so positively that I can conclude that cooperate conversion of private company has real benefit of tax reduction. The forth chapter deals the difficulties and improvements related with conversion. They are considered and reviewed at various aspects such as practical, financial and tax aspect. In fifth chapter, I summarise all of the significant points of this study and have conclusions in various aspects at last. In final point, this study is not enough in sample numbers and sample collecting area for empirical testing of significant tax reduction effect of cooperate conversion and research of more foreign achievements. Those are remained as continuing future studies.

  • PDF

Revised STandards for Reporting Interventions in Clinical Trials of Acupuncture(STRICTA) : Extending the CONSORT Statement (STRICTA(침 임상연구에서 중재 보고를 위한 표준) 개정판: CONSORT Statement의 확충안)

  • Lee, Hyang-Sook;Cha, Su-Jin;Park, Hi-Joon;Seo, Jung-Chul;Park, Jong-Bae J.;Lee, Hye-Jung
    • Korean Journal of Acupuncture
    • /
    • v.27 no.3
    • /
    • pp.1-23
    • /
    • 2010
  • Objectives and methods : The Standards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA) were published in five journals in 2001 and 2002. These guidelines, in the form of a checklist and explanations for use by authors and journal editors, were designed to improve reporting of acupuncture trials, particularly the interventions, thereby facilitating their interpretation and replication. Subsequent reviews of the application and impact of STRICTA have highlighted the value of STRICTA as well as scope for improvements and revision. To manage the revision process a collaboration between the STRICTA Group, the CONSORT Group, and the Chinese Cochrane Centre was developed in 2008. An expert panel with 47 participants was convened that provided electronic feedback on a revised draft of the checklist. At a subsequent face-to-face meeting in Freiburg, a group of 21 participants further revised the STRICTA checklist and planned dissemination. Results : The new STRICTA checklist, which is an official extension of CONSORT, includes six items and 17 sub-items. These set out reporting guidelines for the acupuncture rationale, the details of needling, the treatment regimen, other components of treatment, the practitioner background, and the control or comparator interventions. In addition, and as part of this revision process, the explanations for each item have been elaborated, and examples of good reporting for each item are provided. In addition, the word "controlled" in STRICTA is replaced by "clinical", to indicate that STRICTA is applicable to a broad range of clinical evaluation designs, including uncontrolled outcome studies and case reports. Conclusions : It is intended that the revised STRICTA, in conjunction with both the main CONSORT Statement and extension for nonpharmacologic treatment, will raise the quality of reporting of clinical trials of acupuncture.

Heavy Metal Contents and Antioxidant Activity and Cytotoxic Effect of Red Sea Bream (Pagrus major): Comparative Studies in Domestic and Imported Red Sea Bream (Pagrus major) (국내산 및 수입산 참돔의 중금속 함량 및 항산화 활성과 세포독성 효과 비교)

  • Hwang, Seong Yeon;Bae, Jin Han;Lim, Sun-Young
    • Journal of Life Science
    • /
    • v.25 no.4
    • /
    • pp.450-455
    • /
    • 2015
  • This study compared the heavy metal contents and the effects of extracts from domestic and imported red sea bream on the antioxidant activity and cytotoxicity of human cancer cell lines. The antioxidant activity was measured using the fluorescently sensitive dye, 2’-7’ dichlorofluorescein-diacetate (DCFH-DA), and antiproliferative activity against AGS human gastric adenocarcinoma and HT-29 human colon cancer cell lines, which was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Domestic red sea bream had a higher mercury content when compared to imported red sea bream, but there was no significant difference in the lead content. Treatments with acetone/methylene chloride (A+M) and methanol (MeOH) extracts from domestic and imported red sea bream dose-dependently decreased the H2O2 induced ROS production, compared to the control. The cell viability showed that treatments with the A+M and MeOH extracts had cytotoxicity in the growth of AGS and HT-29 cancer cells. In the case of AGS, the extracts from the domestic red sea bream were higher in inhibiting cancer cell growth, compared to imported red sea bream. Our results demonstrate that the heavy metal contents of domestic and imported red sea bream were below the limit of the Food Code of Korea. The results of the biological activities indicate that the antioxidant activity of extracts from imported red sea bream was more effective, while the extracts from the domestic red sea bream were stronger in cytotoxic activity.

Genome-Wide Association Analyses on Blood Pressure Using Three Different Phenotype Definitions

  • Park, Ji-Wan;Uhmm, Saan-Yong;Shin, Chol;Cho, Nam-H.;Cho, Yoon-Shin;Lee, Jong-Young
    • Genomics & Informatics
    • /
    • v.8 no.3
    • /
    • pp.108-115
    • /
    • 2010
  • Hypertension is the most prevalent disease worldwide and is itself a risk factor for cerebral, cardiac, and renal diseases. The inconsistency of candidate genes suggested by previous genomewide association studies (GWASs) may be due to not only differences in study design and genetic or environmental background but also the difference in the power of analysis between continuous traits and discrete traits. We analyzed 352,228 single nucleotide polymorphisms (SNPs) in 8842 unrelated Koreans obtained from Ansan and Ansung cohorts. We performed a series of GWA analyses using three different phenotype models; young hypertensive cases (278 subjects) versus elderly normotensive controls (680 subjects); the upper 25% (2211 hypertensive cases) versus the lower 25% of the SBP distribution (2211 hypotensive controls); and finally SBP and DBP as continuous traits (8842 subjects). The numbers of young hypertensive cases and elderly normotensive controls were not large enough to achieve genomewide significance. The model comparing the upper 25% subjects to the lower 25% of subjects showed a power that was approximate to that of QTL analysis. Two neighboring SNPs of the ATP2B1 gene, rs17249754 (SBP, p=$2.53^{-10}$; DBP, p=$1.28{\times}10^{-8}$) and rs7136259 (SBP, p=$1.30{\times}10^{-9}$; DBP, p=$6.41{\times}10^{-8}$), were associated with both SBP and DBP. Interestingly, a SNP of the RPL6 gene, rs11066280, revealed a significant genomewide association with SBP in men only (p=$3.85{\times}10^{-8}$), and four SNPs located near the MAN2A1 gene showed a strong association with DBP only in elderly men aged 60-70 years (e.g., rs6421827, p=$4.86{\times}10^{-8}$). However, we did not observe any gene variant attaining genomewide significance consistently in the three phenotype models except for the ATP2B1 gene variants. In general, the association signal with blood pressure was stronger in women than in men. Genes identified in GWASs are expected to open the way for prevention, early diagnosis, and personalized treatment of hypertension.

Exploratory Sensitivity Analysis of Environmental Equity to Spatial to Measures (공간척도 유형에 따른 환경적 형평성의 민감도 분석)

  • Jun, Byong-Woon
    • Journal of the Korean association of regional geographers
    • /
    • v.12 no.4
    • /
    • pp.508-521
    • /
    • 2006
  • The results of environmental equity analysis vary dramatically depending on different methods used. The information and data available to the researcher are also often uncertain and imprecise in empirical studies. A sensitivity analysis approach was used too handle uncertainties and methodological inconsistencies in environmental equity analysis. This paper explores the sensitivity of environmental equity analysis to two spatial measures such as proximity and scale. Two experiments were implemented to evaluate the effects of two spatial measures on the environmental equity analysis using a combination of control and experimental factors. Fulton County, Georgia was selected as a case study area for these experiments. Two major data sets including demographic characteristics and toxic release inventory (TRI) database for the study area in 1990 were integrated into a GIS environment. Two statistical analyses such as independent samples t-test and coefficient of variation were performed to determine the environmental equity in the study area and to compare the relative variability in the socioeconomic characteristics of populations over different spatial measures. The findings from two experiments indicate that the outcomes of environmental equity analysis are slightly sensitive to the buffer distance used to determine the impact zones of TRI facilities, but not to the geographic scale used in the analysis. The findings also suggest that the consequences of these choices can alter spatially and statistically the results in environmental equity analysis.

  • PDF

Study on the Risk of Flammability & Combustion of Liquid Mixtures such as Alcohols (알코올류 등의 액체 혼합물에 대한 인화 및 연소 위험성에 관한 연구)

  • Koh, Jae-Sun
    • Journal of the Society of Disaster Information
    • /
    • v.15 no.4
    • /
    • pp.634-647
    • /
    • 2019
  • Purpose: Currently, many chemicals are used in industrial and real life, and many substances are used in the form of a single substance, but most of them are used in the form of a mixture, and there is a need for a criterion for judging the danger of these substances. Method: Therefore, this study aims to confirm the risk criteria of the mixture through experimental studies on flammable mixtures in order to secure the effectiveness of the details of the existing Dangerous Goods Safety Management Act angerous Goods Judgment Criteria and to ensure the reliability and reproducibility of the dangerous goods judgment. Result: Experimental results show that alcohol flash point is mixed with water, which is a non-flammable liquid. Similar flash point trends occurred around 60% on an alcohol basis. In addition, in the case of flammable-combustible mixtures, there was little change in flash point if the flash point difference of the two materials was not large, and if the flash point difference of the two materials was low, the flash point tended to increase with the increase of the high flash point material. Conclusion: In the future, the test results may provide reference data on the experimental criteria for the flammable liquids that are cracked at the fire site.