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Artifactual Perfusion Defects due to the Parameters of Reconstruction Filter in Tc-99m-MIBI Myocardial SPECT Images (Tc-99m-MIBI 심근 SPECT 영상에서 재구성 필터에 의한 인위적 관류결손에 관한 연구)

  • Kwark, Cheol-Eun;Lee, Kyung-Han;Lee, Dong-Soo;Park, Yong-Woo;Chung, June-Key;Lee, Myung-Chul;Seo, Joung-Don;Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
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    • v.29 no.1
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    • pp.41-47
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    • 1995
  • Tc-99m-MIBI(Sestamibi) myocardial SPECT along with T1-201 tomographic imaging has demonstrated wide application and high image qualify sufficient for the diagnosis of myocardial perfusion defect, which consequently reflects regional myocardial blood flow, The qualitative values of myocardial SPECT with Tc-99m-MIBI as well as the quantitative cases depend in some degree on the reconstruction techniques of multiple projections. Filtered backprojection(FBP) is the common standard for reconstruction rather than the complicated and time-consuming arithmetic methods. In FBP it Is known that the distribution of radioactivity in reconstructed transverse slices varies with the selected filter parameters such as cutoff frequencies and order(Butterworth case). The cutoff frequencies basically remove and decrease the true radioactive distribution and alter the pixel counts, which lead to underestimation of true counts in specific myocardial regions. In this study, we have investigated the effect of cutoff frequencies of reconstruction filter on the artifactually induced perfusion defects, which are often demonstrated near inferior and/or inferoseptal cardiac walls due to the intense hepatic uptake of Tc-99m-MIBI. A computerized method for identifying the relative degree of artifactual perfusion defect and for comparing those degrees along with the relative amount of hepatic uptake to myocardium was developed and patient images were studied to observe the quantitative degree of underestimation of myocardial perfusion, and to propose some reasonable thresh-old of cutoff frequency in the diagnosis of perfusion defect quantitatively. We concluded that from the quantitative viewpoint cutoff frequencies may be used as high as possible with the sacrifice of homogeneity of image quality, and those frequencies lower than the common 0.3 Nyquist frequency would reveal severe degradation of radio-active distribution near inferior and/or Inferoseptal myocardium when applying Butterworth or low pass filter.

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The Effects of Cooperative Learning to Study the Unit 'Metabolism' in High School: Application of STAD Model (고등학교 생물 '물질대사' 단원에서 협동학습의 효과: STAD 모형의 적용)

  • Chung, Young-Lan;Lee, Hye-Won
    • Journal of The Korean Association For Science Education
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    • v.23 no.1
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    • pp.35-46
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    • 2003
  • Problem solving ability, having been thought as one of the most important goals of science education is also a primary task for the current education. Indeed, the students' problem solving ability has shown almost no actual progress, despite our long accumulated science education. Under this circumstances, cooperative learning, a way to grow students' positive inter-dependence and problem solving ability in the basis of their active participation and discussion, was proposed as an effective teaching method. But, results have not consistently shown the advantage of cooperative learning over traditional learning for promoting academic achievement in science. Studies have consistently shown greater effectiveness on affective aspects. But, relatively few have focused on biology in Korea. The purpose of this study was to examine the effects of cooperative learning on the achievement and attitude of high school biology students. The pretest-posttest control group design was applied. The sample consisted of 50 11th-grade female students in experimental group(cooperative learning Student Team Achievement Division model) and 50 students in control group(traditional learning). Students in both groups recieved identical content instruction on the unit 'II. Methabolism'. These groups were treated for 13 hours during 5 weeks. Achievement data were collected using a 24-item multiple-choice test(content validity= .85). Science attitude was measured by an instrument which adapted by Kim In Hee(1994). The instrument(Cronbach $\alpha$=.89) included 40 items in four subscales: attitude toward science, social meaning of science, attitude toward science class, and scientific attitude. An analysis of covariance (ANCOVA) was used as the data analysis procedure. For the achievement data, no significant difference exists between the cooperative and traditional groups (p> .05). But, cooperative learning was effective in low-ability students(p < .05). For the science learning attitude data, cooperative learning was more effective than the traditional one(p< .05). Students in the cooperative group acheived better than those in traditional one especially in the subscale of attitude toward science class. There was no meaningful difference of the two methods in both high and average ability students, while cooperative learning was more effective than the traditional one in low ability students(p<.05).

Design of a Bit-Serial Divider in GF(2$^{m}$ ) for Elliptic Curve Cryptosystem (타원곡선 암호시스템을 위한 GF(2$^{m}$ )상의 비트-시리얼 나눗셈기 설계)

  • 김창훈;홍춘표;김남식;권순학
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.12C
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    • pp.1288-1298
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    • 2002
  • To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.

The Influence of Adjuvants on Herbicide Activity of Streptomyces scopuliridis KR-001 (토양 방선균 Streptomyces scopuliridis KR-001 균주 배양액의 살초활성을 증가시키는 Adjuvant 탐색)

  • Kim, Jae Deok;Sin, Hoon Tak;Kim, Young Sook;Ko, Young Kwan;Cho, Nam Kyu;Hwang, Ki Hwan;Koo, Suk Jin;Choi, Jung Sup;Park, Kee Woong
    • Weed & Turfgrass Science
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    • v.4 no.4
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    • pp.288-294
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    • 2015
  • This study was conducted to investigate efficient adjuvants to increase herbicidal efficacy of metabolites from Streptpmyces scopuliridis KR-001. Commonly used 21 adjuvants mixed with the metabolites were applied to eight weed species (six grass weeds and two broadleaved weeds). Based on the visual evaluation, two adjuvants, LE7 (Polyoxyethylene lauryl ether) and EP4C (Sodium bis (2-ethylhexyl) sulfosuccinate), were selected as most efficient adjuvants to elevate herbicidal efficacy of the metabolites. Higher efficacy in the LE7 and EP4C was obtained when overall spray volume was $2,000L\;ha^{-1}(65{\mu}g\;a.i.\;ml^{-1})$ than $1,000L\;ha^{-1}(130{\mu}g\;a.i.\;ml^{-1})$. Field study demonstrated that $1,300{\mu}g\;ml^{-1}$ of metabolites from KR-001 applied with EP4C at concentration of $2{\mu}g\;ml^{-1}$ provided a highly effective post-emergence weed control which was almost equivalent to the glufosinate-ammonium at $540g\;a.i.\;ha^{-1}$. On the basis of these results, combination and multiple application methods could be developed to enhance herbicidal efficacy of metabolites from KR-001.

Analysis of Bone Marrow Micrometastasis Using RT-PCR in Patients with Small Cell Lung Carcinoma (소세포 폐암에서 역전사 중합효소 연쇄반응(RT-PCR)을 이용한 골수 미세전이(naicronaetastasis)의 분석)

  • Kim, Tae-You;Park, Jong-Kook;Ryoo, Baek-Ryeol;Im, Yung-Hyuck;Kang, Yoon-Koo
    • Tuberculosis and Respiratory Diseases
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    • v.47 no.6
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    • pp.797-806
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    • 1999
  • Background: About 20% of small cell lung cancer(SCLC) patients have bone marrow(EM) metastasis at the time of diagnosis and the remaining patients are also considered with micrometastasis. In an attempt to detect EM micrometastasis, we used cytokeratin(CK)-20 as a molecular marker, which is specific for epithelial cells. Method: A sensitive RT-PCR assay was used to compare CK-20 expression both in SCLC cell line H209 and normal leukocyte and to evaluate EM aspirates of 28 SCLC patients. Result: H209 cell line showed CK-20 expression but normal leukocyte did not, suggesting CK-20 expression is lung tissue-specific. Of 28 patients(11 limited disease, 17 extensive disease), only 2(1/11, 1/17) samples tested revealed positive signal for CK-20. Two patients with CK-20 expression had EM metastasis or multiple bone involvement during follow-up. Conclusion: Although circulating tumor cells were detected in EM of small portion of patients with bone metastasis, CK-20 doesn't seem to be a reliable marker for the detection of micrometastasis in SCLC. This study emphasizes that identification of more specific marker for micrometastsis is mandatory prior to clinical application.

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Mapping Categories of Heterogeneous Sources Using Text Analytics (텍스트 분석을 통한 이종 매체 카테고리 다중 매핑 방법론)

  • Kim, Dasom;Kim, Namgyu
    • Journal of Intelligence and Information Systems
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    • v.22 no.4
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    • pp.193-215
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    • 2016
  • In recent years, the proliferation of diverse social networking services has led users to use many mediums simultaneously depending on their individual purpose and taste. Besides, while collecting information about particular themes, they usually employ various mediums such as social networking services, Internet news, and blogs. However, in terms of management, each document circulated through diverse mediums is placed in different categories on the basis of each source's policy and standards, hindering any attempt to conduct research on a specific category across different kinds of sources. For example, documents containing content on "Application for a foreign travel" can be classified into "Information Technology," "Travel," or "Life and Culture" according to the peculiar standard of each source. Likewise, with different viewpoints of definition and levels of specification for each source, similar categories can be named and structured differently in accordance with each source. To overcome these limitations, this study proposes a plan for conducting category mapping between different sources with various mediums while maintaining the existing category system of the medium as it is. Specifically, by re-classifying individual documents from the viewpoint of diverse sources and storing the result of such a classification as extra attributes, this study proposes a logical layer by which users can search for a specific document from multiple heterogeneous sources with different category names as if they belong to the same source. Besides, by collecting 6,000 articles of news from two Internet news portals, experiments were conducted to compare accuracy among sources, supervised learning and semi-supervised learning, and homogeneous and heterogeneous learning data. It is particularly interesting that in some categories, classifying accuracy of semi-supervised learning using heterogeneous learning data proved to be higher than that of supervised learning and semi-supervised learning, which used homogeneous learning data. This study has the following significances. First, it proposes a logical plan for establishing a system to integrate and manage all the heterogeneous mediums in different classifying systems while maintaining the existing physical classifying system as it is. This study's results particularly exhibit very different classifying accuracies in accordance with the heterogeneity of learning data; this is expected to spur further studies for enhancing the performance of the proposed methodology through the analysis of characteristics by category. In addition, with an increasing demand for search, collection, and analysis of documents from diverse mediums, the scope of the Internet search is not restricted to one medium. However, since each medium has a different categorical structure and name, it is actually very difficult to search for a specific category insofar as encompassing heterogeneous mediums. The proposed methodology is also significant for presenting a plan that enquires into all the documents regarding the standards of the relevant sites' categorical classification when the users select the desired site, while maintaining the existing site's characteristics and structure as it is. This study's proposed methodology needs to be further complemented in the following aspects. First, though only an indirect comparison and evaluation was made on the performance of this proposed methodology, future studies would need to conduct more direct tests on its accuracy. That is, after re-classifying documents of the object source on the basis of the categorical system of the existing source, the extent to which the classification was accurate needs to be verified through evaluation by actual users. In addition, the accuracy in classification needs to be increased by making the methodology more sophisticated. Furthermore, an understanding is required that the characteristics of some categories that showed a rather higher classifying accuracy of heterogeneous semi-supervised learning than that of supervised learning might assist in obtaining heterogeneous documents from diverse mediums and seeking plans that enhance the accuracy of document classification through its usage.

Analysis of User′s Satisfaction to the Small Urban Spaces by Environmental Design Pattern Language (환경디자인 패턴언어를 통해 본 도심소공간의 이용만족도 분석에 관한 연구)

  • 김광래;노재현;장동주
    • Journal of the Korean Institute of Landscape Architecture
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    • v.16 no.3
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    • pp.21-37
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    • 1989
  • Environmental design pattern of the nine Small Urban Spaces at C.B.D. in City of Seoul are surveyed and analyzed for user's satisfaction and behavior under the environmental design evaluation by using Christopher Alexander's Pattern Language. Small Urban Spaces as a part of streetscape are formed by physical factors as well as visual environment and interacting user's behavior. Therefore, user's satisfaction and behavior at the nine Urban Small Spaces were investigated under the further search for some possibilities of application of those Pattern Languages. A pattern language has a structure of a network. It is used in sequence, going through the patterns, moving always from large patterns to smaller, always from the ones which create comes simply from the observation that most of the wonderful places of the city were not blade by architects but by the people. It defines the limited number of arrangements of spaces that make sense in any given culture. And it actually gives us the power to generate these coherent arrangement of space. As a results, 'Plaza', 'Seats'and 'Aecessibility' related design Patterns are highly evaluated by Pattern Frequency, Pattern Interaction and their Composition ranks, thus reconfirm Whyte's Praise of urban Small Spaces in our inner city design environments. According to the multiple regression analysis of user's evaluation, the environmental functions related to the satisfaction were 'Plaza', 'Accessibility' and 'Paving'. According to the free response, user's prefer such visually pleasing environmental design object as 'Waterscape' and 'Setting'. In addition to, the basic needs in Urban Small Spaces are amenity facilities as bench, drinking water and shade for rest.

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Application of Polymerase Chain Reaction (PCR) to the Diagnosis of Tuberculosis (Polymerase Chain Reaction (PCR)을 이용한 결핵의 진단에 관한 연구)

  • Kim, Ho-Joong;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo;Kim, Keun-Youl;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
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    • v.39 no.6
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    • pp.517-525
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    • 1992
  • Background: Since its development by Saiki et al, polymerase chain reaction (PCR) has been very useful in various fields of molecular biology. PCR can be used for the detection of a very small amount of microbial agent, and is especially useful in those patients who are difficult to diagnose microbiologically or serologically. Mycobacterium tuberculosis is a very slowly growing organism and AFB staining frequently shows false negative results, and therefore PCR would be a very rapid, easy, and sensitive diagnostic method for the diagnosis of Mycobacterium tuberculosis. Method: To compare PCR with conventional methods in diagnosing Mycobacterium tuberculosis in sputum, we used sputa of patients who visited or were admitted to Seoul National University Hospital. The amplification targets were 383 base pair DNA, a part of 2520 base pair DNA encoding 65 kD Mycobacterium tuberculosis specific protein (the primers are TB-1, -2), and 123 base pair DNA, a part of IS6110 fragment, which multiple copies are known to exsist PCR one genome (the primers are Sal I-1, -2). We also requested AFB staing and culture to the lab of Seoul National University Hospital with the same sample and compared the results. Results: 1) Using TB-1, -2 primers, PCR was positive in 73.1% (19/26) of culture positive sputa, in 12.5% (1/8) of culture negative. but clinically diagnosed tuberculous sputa, and was negative in all sputa of patients who were clinically diagnosed as non-tuberculous etiology. 2) Using Sal I-I, -2 primers, PCR was positive in 94.1% (32/34) of culture positive sputa, in 23.1% (6/26) of culture negative, but clinically diagnosed tuberculous sputa, and was negative in 87.5% (14/16) of sputa from patients who were clinically diagnosed as non-tuberculous etiology. Conclusion: PCR could be a very rapid, sensitive and specific method for the diagnosis of Mycobacterium tuberculosis in sputa, and further studies should be followed for the development of easier method.

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FACTORS AFFECTING CHILDREN'S DENTAL UTILIZATION: AN APPLICATION OF THE ANDERSEN MODEL (앤더슨 뉴만모형을 이용한 아동의 치과의료이용행태에 영향을 미치는 요인에 관한 연구)

  • Kim, Soo-Nam;Lee, Heung-Soo;Kim, Kyung-Hey;Kim, Dae-Eop;Park, Deug-Hee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.25 no.1
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    • pp.162-170
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    • 1998
  • The purpose of this study is to provide framework for understanding children's dental utilization. In this paper Andersen-Newman's model is applied to the use of dental visits. This model consists of predisposing, enabling, and need components that describe a person's decision to use dental health services. One thousand, nine hundred seven children and their mothers were selected for the study. The children were fourth grade to sixth grade in elementary schools in Iksan city, Korea. Models are operationalized using stepwise multiple regression analysis and path analysis. The number of independent variables used in the analysis was 39 in total, ie 32 predisposing components, 6 enabling components, and 1 need component. Children's Dental utilization was measured based on the number of visits. The data collected by means of a questionnaire survey. In this study, the amount of variance by the model was 25 percent. Predisposing factors had the greatest effect on utilization. Number of restricted activity days caused by oral disease, having a regular dental care, and susceptibility on oral disease of children were found to have significant major effects on dental utilization of children. Mother's dental visits was most important factor affecting dental utilization of children.

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The Recognition Characteristics of Science Gifted Students on the Earth System based on their Thinking Style (과학 영재 학생들의 사고양식에 따른 지구시스템에 대한 인지 특성)

  • Lee, Hyonyong;Kim, Seung-Hwan
    • Journal of Science Education
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    • v.33 no.1
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    • pp.12-30
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    • 2009
  • The purpose of this study was to analyze recognition characteristics of science gifted students on the earth system based on their thinking style. The subjects were 24 science gifted students at the Science Institute for Gifted Students of a university located in metropolitan city in Korea. The students' thinking styles were firstly examined on the basis of the Sternberg's theory of mental self-government. And then, the students were divided into two groups: Type I group(legislative, judicial, global, liberal) and Type II group(executive, local, conservative) based on Sternberg's theory. Data was collected from three different type of questionnaires(A, B, C types), interview, word association method, drawing analyses, concept map, hidden dimension inventory, and in-depth interviews. The findings of analysis indicated that their thinking styles were characterized by 'Legislative', 'Executive', 'Anarchic', 'Global', 'External', 'Liberal' styles. Their preference were conducting new projects and using creative problem solving processes. The results of students' recognition characteristics on earth system were as follows: First, though the two groups' quantitative value on 'System Understanding' was very similar, there were considerable distinctions in details. Second, 'Understanding the Relationship in the System' was closely connected to thinking styles. Type I group was more advantageous with multiple, dynamic, and recursive approach. Third, in the relation to 'System Generalization' both of the groups had similar simple interpretational ability of the system, but Type I group was better on generalization when 'hidden dimension inventory' factor was added. On the system prediction factor, however, students' ability was weak regardless of the type. Consequently, more specific development strategies on various objects are needed for the development and application of the system learning program. Furthermore, it is expected that this study could be practically and effectively used on various fields related to system recognition.

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