• Title/Summary/Keyword: 통계추론

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Exploring the Thalamus of the Human Brain using Tractography Analysis at 3Tesla MRI (3 Tesla MRI에서 트랙토그래피 분석을 이용한 시상 탐색)

  • Im, Sang-Jin;Kim, Joo-Yeon;Baek, Hyeon-Man
    • Journal of the Korean Society of Radiology
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    • v.15 no.4
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    • pp.555-564
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    • 2021
  • Thalamus is known to play an important role in the regulation of nerve function. Thalamus, located in the center of the brain, is involved in sleep, arousal, and emotional regulation, and has been reported to be associated with multiple sclerosis, essential tremors, and neurodegenerative diseases such as Parkinson's disease. In addition, it has been reported that iron deposits in the thalamus can cause depressive symptoms with age. Although there are discrepancies between studies, it can be deduced that the thalamus region has a clear effect on neurological disorders due to a strong relationship between the thalamus and neurological functions such as emotional control and processing. Through tractography analysis, the connectivity between the detailed areas of each subcortical region was investigated in the form of a matrix, showing strong connectivity and weak interhemispheric connectivity. In the 59> group, the WM connectivity of thalamus was found to be weaker than those of the two groups. Comparisons between the two groups showed that the young groups (10-39 and 40-59) had higher connection intensity than the 59> group and that statistically significant differences in 3 connection pathways were found in each hemisphere. A decrease in thalamus-related connection strength in aging has shown that it can affect emotional and neurological disorders such as anxiety and depression, and network measurements can help assess cognitive impairment across clinical conditions.

Development of a surrogate model based on temperature for estimation of evapotranspiration and its use for drought index applicability assessment (증발산 산정을 위한 온도기반의 대체모형 개발 및 가뭄지수 적용성 평가)

  • Kim, Ho-Jun;Kim, Kyoungwook;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
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    • v.54 no.11
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    • pp.969-983
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    • 2021
  • Evapotranspiration, one of the hydrometeorological components, is considered an important variable for water resource planning and management and is primarily used as input data for hydrological models such as water balance models. The FAO56 PM method has been recommended as a standard approach to estimate the reference evapotranspiration with relatively high accuracy. However, the FAO56 PM method is often challenging to apply because it requires considerable hydrometeorological variables. In this perspective, the Hargreaves equation has been widely adopted to estimate the reference evapotranspiration. In this study, a set of parameters of the Hargreaves equation was calibrated with relatively long-term data within a Bayesian framework. Statistical index (CC, RMSE, IoA) is used to validate the model. RMSE for monthly results reduced from 7.94 ~ 24.91 mm/month to 7.94 ~ 24.91 mm/month for the validation period. The results confirmed that the accuracy was significantly improved compared to the existing Hargreaves equation. Further, the evaporative demand drought index (EDDI) based on the evaporative demand (E0) was proposed. To confirm the effectiveness of the EDDI, this study evaluated the estimated EDDI for the recent drought events from 2014 to 2015 and 2018, along with precipitation and SPI. As a result of the evaluation of the Han-river watershed in 2018, the weekly EDDI increased to more than 2 and it was confirmed that EDDI more effectively detects the onset of drought caused by heatwaves. EDDI can be used as a drought index, particularly for heatwave-driven flash drought monitoring and along with SPI.

An Empirical Study on the Effects of Entrepreneurship on Entrepreneurial Intention: Focusing on Moderating Effects of Fear of Entrepreneurial Failure (기업가정신이 창업의지에 미치는 영향에 관한 연구 - 창업실패두려움의 조절효과를 중심으로)

  • Kim, Young Hee;Yang, Dong Woo
    • Korean small business review
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    • v.41 no.4
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    • pp.65-86
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    • 2019
  • This study empirically analyzed how the elements of entrepreneurship and the fear of entrepreneurial failure influence entrepreneurial intention with each other in a situation that encourages startups. In particular, the moderating effect of fear of entrepreneurial failure was verified by dividing the fear of entrepreneurial failure into three sub-variables: fear of financial loss, fear of psychological loss, and fear of career loss. As a result, it was found that proactiveness and risk-taking had a positive effect on entrepreneurial intention, but innovativeness did not. Fear of entrepreneurial failure(all of sub-variables) was found to have no significantly moderating effect on the relationship between entrepreneurship and entrepreneurial intention. Therefore it seemed to have a negative effect as a independent variable. However, considering the regression coefficient(β) is positive or negative depending on the interaction terms of the sub-variables of fear of entrepreneurial failure and the entrepreneurship, it could be inferred that the moderating effect could be positive or negative. Based on this research results, a sophisticated entrepreneurship education program to inspire entrepreneurship and lower the fear of failure is needed in order to promote startups. And at the same time, a social safety net construction plan to reduce the fear of entrepreneurial failure needs to be prepared.

Analysis of the Improvement and Effectiveness of the Experiment to Find Out That Gas Occupies Space (기체가 공간을 차지하고 있음을 알아보는 실험의 개선 방안 및 효과 분석)

  • Chae, Heein
    • Journal of Korean Elementary Science Education
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    • v.43 no.2
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    • pp.269-283
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    • 2024
  • This study compared the characteristics of an experiment f or determining whether gas occupies space presented in elementary school science textbooks to examine the validity of the experiment, identify and improve problems in its presentation, and verify its effectiveness. This study interviewed third-year elementary school teachers who had experience teaching this experiment to students. Based on teachers' opinions and observations, this study identified issues with the current experiment, developed an improved experiment, and determined its effectiveness. Through this analysis, three key findings emerged. First, the study found that the original experiment on gases was presented in the same or highly similar manner in 5 of 7 textbooks (71.4%). Thus, while various textbooks have been developed with the aim of promoting diversity and creativity in scientific literature, most experiments presented in these books are identical. Second, the existing experiment was not suitable for its target audience (third-year elementary school students) and was difficult to observe directly. The interviewed teachers also deemed the validity of the experiment to be considerably low. Finally, the original experiment was improved; this improved version was determined to be highly valid, showing a statistically significant difference compared with the original experiment. The improved experiment was effective for students as it involved activities suitable for their intellectual level and was directly observable through the senses. Thus, the study analyzed and improved an existing science experiment f or elementary students, providing insights into the 2022 revised science authorized textbooks and implications for future textbook development.

Environmental Equity Analysis of the Accessibility of Urban Neighborhood Parks in Daegu City (대구시 도시근린공원의 접근성에 따른 환경적 형평성 분석)

  • Seo, Hyun-Jin;Jun, Byong-Woon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.4
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    • pp.221-237
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    • 2011
  • This study aims to investigate the environmental equity of the accessibility to urban neighborhood parks in the city of Daegu. The spatial distribution of urban neighborhood parks was explored by spatial statistics and the spatial accessibility to them was then evaluated by both minimum distance and coverage approaches. Descriptive and inferential statistics such as proximity ratio, Mann Whitney U test, and logistic regression were used for comparing the socioeconomic characteristics over different accessibilities to the neighborhood parks and then testing the distributional inequity hypothesis. The results from the minimum distance method indicated that Dalseo-gu had the best accessibility to the neighborhood parks while Dong-gu had the worst accessibility. It was apparent with the coverage method that Dalseo-gu had the best accessibility whereas Dong-gu and Nam-gu had the worst accessibility to the neighborhood parks at 500m and 1,000m buffer distances. There existed the spatial pattern of environmental inequity in old towns with respect to population density and the percentage of people under the age of 18. The spatial pattern of environmental inequity in new towns was explored on the basis of the percentage of people over the age of 65, the percentage of people below the poverty level, and the percentage of free of charge rental housing. These results were closely related to the development process of urban parks in Daegu stimulated by the quantitative urban park policy, urban development process, and residential location pattern such as permanent rental housing and free of charge rental housing. This study further extends the existing research topics of environmental justice related to the distributional inequity of environmental disamenities and hazards by focusing on environmental amenities such as urban neighborhood parks. The results from this study can be used in making the decisions for urban park management and setting up urban park policy with considering the social geography of Daegu.

An Analysis on the Effect of Independent Study Project Learning on Self-Directed Learning Ability and Mathematical Self-Efficacy of the Mathematically Gifted Elementary Students (독자적 연구 프로젝트 학습이 초등수학영재의 자기주도적 학습능력과 수학적 자기효능감에 미치는 영향 분석)

  • Goo, Jong Seo;Ryu, Sung Rim
    • Journal of Elementary Mathematics Education in Korea
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    • v.19 no.2
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    • pp.205-230
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    • 2015
  • The purpose of this study is, targeting 5th and 6th grades mathematically gifted elementary students, to analyze the effect of independent study project learning on self-directed learning ability and mathematical self-efficacy, and based on the results, examine the implications that independent study project learning has in special education for the gifted. In order to solve the study problems, 5th grade mathematically gifted elementary students(40) and 6th grade mathematically gifted elementary students(39) who had passed the selection criteria of D education institute for the gifted and had been receiving special education for the gifted were selected. The study results are as below. First, although self-directed learning ability had no significant difference at p<0.05, it statistically had some differences in averages between pre-test and post-test results. Second, although mathematical self-efficacy had no significant difference at p<0.05, it statistically had some differences in averages between pre-test and post-test results. Third, in the aspects of self-directed learning ability and mathematical self-efficacy, independent study project learning had a more positive effect on 5th grade mathematically gifted elementary students than 6th grade mathematically gifted elementary students. In addition, it had significant differences in 'the level of mathematical tasks', a sub-level of mathematical self-efficacy, and 'the openness of learning', 'the initiative of learning', and 'a sense of responsibility for learning', sub-levels of self-directed learning ability. These results imply that independent study project learning has a positive effect on self-directed learning ability and mathematical self-efficacy of mathematically gifted elementary students so that it could be meaningfully used as a teaching method for special education for the gifted at educational sites of independent study project learning.

Developmental Standard of the Short Sensory Profile for Korean Children of School Age (7 to 9 years old) (만 7~9세 학령기아동의 감각통합 임상관찰평가의 발달기준에 관한 일연구)

  • Ji, Seok-Yeon;Kim, Mi-Sun;Keum, Hyo-Jin;Kim, Sung-Hee
    • The Journal of Korean Academy of Sensory Integration
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    • v.7 no.1
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    • pp.27-36
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    • 2009
  • Introduction : Occupational therapists commonly use clinical observation to assess neuromuscular function witch is a fundamental component of sensory integration function. Clinical Observation of Motor and Postural Skills (COMPS) is a standardized assessment with seven items and used to screen if a child's problem is due to neuromuscular and sensory integration system. However, developmental standard of the test need to be validated with Korean children. Objective : This study is purposed to propose developmental standard of the COMPS for Korean children. Method : Seven to nine years old students (76 male and 70 female) participated in this study. In order to find out any difference by gender and age, the data was analyzed using t-test and ANOVA. Results : There is no significant difference by gender for all other items except Prone Extension Position (PEP). There is significant difference between children who are 7 years old and those who are 9 years old for Slow Motion(SM), Finger-Nose Touching (FNT), Asymmetrical Tonic Neck Reflex (ATNR), Supine Flexion(SF). There is also significant difference between those who are 8 years old and 9 years old for SM, FNT, ATNR. However, there is no significant difference between those who are 7 years and 8 years old. Conclusions : This study examines any difference in neuromuscular characteristics by age among school-aged children, based on the COMPS. The result of this study will provide a good evidence to establish developmental standard of COMPS for Korean children. It issuggested to continue further standardization work of the COMPS in order to establish a developmental standard for Korean children.

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Study on Air Logistics Service Provider's Performance Under Post Covid19 Situation: Focusing on Trust and Reciprocity (포스트 코로나 시대의 항공물류 서비스기업의 경영성과에 대한 연구: 신뢰 및 호혜 개념을 중심으로)

  • Moon, Myungjoo;Koh, InKon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.3
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    • pp.135-145
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    • 2022
  • Due to COVID 19, we are facing unprecedented phenomena. Among various industries, the aviation industry, as it is directly affected by the corona crisis is actively establishing various survival strategies, such as expanding cargo transportation. The market size of air cargo transportation is continuously increasing due to the characteristics that distinguish it from other transportation, and as individualism and selfishness deepen in the aftermath of COVID 19, it can be inferred that the concept of reciprocity within distribution channels will become important in the post-corona era. The specific contents of this study(research question) are as follows. First, as a central member of the air logistics distribution channel, logistics service companies business process and the sub-dimensions of trust of are identified, and how trust is built with transportation companies is investigated. Second, the effect of such trust on the various performances of logistics service companies is analyzed. Third, we examine whether the influences of the sub-dimensions of trust change according to the perceived reciprocity of logistics service companies. In addition, we investigate whether the perceived reciprocity changed before and after the corona situation. In particular, this study theoretically integrates the concepts of trust and commitment, which have been distinguished in many prior studies, to improve the parsimony and practicality of the research model. This study will be able to present useful academic and practical implications by empirically examining how trust is built between members of the air logistics distribution channel and furthermore, how much it affects the performance of logistics service companies, and by identifying the moderating effect of reciprocity.

Clinical Study of the Correlation of Tumor Necrosis Factor Alpha and the Proteinuria of Henoch-Schönlein Nephritis and Idiopathic Nephrotic Syndrome (Henoch-Schönlein Purpura 신염과 특발성 신증후군에서 Tumor Necrosis Factor Alpha와 단백뇨와의 관련성에 관한 임상적 연구)

  • Jeong, Dong-Ho;Park, Jeong-Hyun;Jeong, Hye-Cheon;Koo, Hyun-Hoe;Lee, Jun-Ho;Ha, Tae-Sun
    • Clinical and Experimental Pediatrics
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    • v.45 no.2
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    • pp.240-246
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    • 2002
  • Purpose : It is not clear that the development of glomerular injury and aggravation by tumor necrosis factor alpha($TNF-{\alpha}$) is related to intrarenal or serum concentration of $TNF-{\alpha}$. So, we studied the relationship between the concentration of $TNF-{\alpha}$ and aggravation of glomerular damage in the Henoch-$Sch{\ddot{o}}nlein$ nephritis(HSN) and idiopathic nephrotic syndrome(INS). Methods : We collected the sera and urines of 21 patients with Henoch-$Sch{\ddot{o}}nlein$ purpura(HSP) and 22 patients with INS visited Chungbuk National University hospital from March 1998 to March 2001. The concentration of $TNF-{\alpha}$ in the sera and urines were measured by sandwich ELISA. Results : Serum $TNF-{\alpha}$ levels in the HSP patients with renal involvement were significantly higher than those without renal involvement(P=0.009). But urine $TNF-{\alpha}$ levels have no correlation with renal involvement(P=0.088). In the HSN patients, proteinuria have a significant correlation with serum $TNF-{\alpha}$ levels(P=0.004) but less correlation with urine $TNF-{\alpha}$ levels(P=0.053). Otherwise, proteinuria have no correlation with serum $TNF-{\alpha}$ levels(P=0.763) but have a significant correlation with urine $TNF-{\alpha}$ levels(P=0.007) in INS. Conclusion : These result suggest that the serum concentration of $TNF-{\alpha}$ would be important to glomerular involvement in HSP. And, it is interesting that proteinuria shows a significant relation with serum $TNF-{\alpha}$ levels in the HSN, but with urine $TNF-{\alpha}$ levels in the INS. This means the major production of $TNF-{\alpha}$ may be originated by extrarenal inflammation in the HSN and by intrarenal tubulo-interstitial damage due to proteinuria in the INS.

Evaluation on the Implementation of Girl Friendly Science Activity (여학생 친화적 과학활동 프로그램의 운영 평가)

  • Jhun, Young-Seok;Shin, Young-Joon
    • Journal of The Korean Association For Science Education
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    • v.24 no.3
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    • pp.442-458
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    • 2004
  • This study was conducted to develop a plan for a large-scale implementation of the Girl Friendly Science Program based on the results of analysis and investigation of its current pilot implementation, Girl Friendly Science Program materials, which was first developed in 1999 with the support from Ministry of Gender Equality, consist of 1) five theme-based units that are specifically targeted individual students' unique ability, aptitude, and career choice, and 2) differentiated learning materials for 7th through 10th grade female students. All the materials are available at the homepage (http://tes.or.kr/gfsp.cgi) of 'Teachers for Exciting Science(the organization of science teachers in Seoul area)'. Since the materials are well organized by topic and grade level and presented in both Korean word process document and html format, anyone can easily access to the materials for their own instructional use. Ever since its launch the number of visitors to the homepage has been constantly increasing. The evaluation results of the current pilot implementation of the materials that targeted individual students' ability and aptitude showed that it scored high in terms of its alignment to the original purpose, content, level, and effectiveness to implement in classrooms. However, its evaluation scores were low in terms of the convenience for teachers to guide the materials, and its organization and operation. The results also showed a significant change in students' perception of science, and students' positive experiences of science through various interdisciplinary activities. On the other hand, the evaluation of students' experiences with the materials showed that students' assessment about an activity was largely depending on a success or failure of their experiences. Overall, students' evaluation of activities scores were low for simple activities such as cutting off or pasting papers. According to students' achievement test results, differences between pre and post test scores in the Affective Domain was statistically significant (p<0.05), but not in Inquiry Domain. Based on teachers observations, numerous schools where have run this program reported that students' abilities to cooperate, discuss, observe and reason with evidences were improved. In order to implement this program in a larger scale, it is critical to have a strong support of teachers and induce them to change their teaching strategy through building a community of teachers and developing ongoing teacher professional development programs. Finally, there still remain strong needs to develop more programs, and actively discover and train more domestic woman scientists and engineers and collaborate with them to develop more educational materials for girls in all ages.