• Title/Summary/Keyword: best focal point

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APPLICATION OF HISTOGRAM OUTLIER ANALYSIS ON THE IMAGE DEGRADATION MODEL FOR BEST FOCAL POINT SELECTION

  • Shin, Hyun-Kyung
    • Journal of applied mathematics & informatics
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    • v.27 no.1_2
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    • pp.175-182
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    • 2009
  • Microscopic imaging system often requires the algorithm to adjust location of camera lenses automatically in machine level. An effort to detect the best focal point is naturally interpreted as a mathematical inverse problem [1]. Following Wiener's point of view [2], we interpret the focus level of images as the quantified factor appeared in image degradation model: g = $f{\ast}H+{\eta}$, a standard mathematical model for understanding signal or image degradation process [3]. In this paper we propose a simple, very fast and robust method to compare the degradation parameters among the multiple images given by introducing outlier analysis of histogram.

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The Clinical Value of Dual Time Point F-18 FDG PET/CT Imaging for the Differentiation of Colonic Focal Uptake Lesions (장관 내 국소 섭취증가 병소의 감별에 있어 추가 지연 F-18 FDG PET/CT의 임상적 유용성)

  • Kim, Jin-Suk;Lim, Seok-Tae;Jeong, Young-Jin;Kim, Dong-Wook;Jeong, Hwan-Jeong;Sohn, Myung-Hee
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.4
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    • pp.309-316
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    • 2009
  • Purpose: F-18 FDG can be accumulated in the liver, bowel, kidney, urinary tract, and muscles physiologically. The aim of this study was to evaluate the clinical value of dual time point 18F-FDG PET /8 imaging for the differentiation of the colonic focal uptake lesions. Materials and Methods: One hundred thirty two patients (M:F = 77:55, Age 62.8$\pm$11.6 years) underwent $^{18}$F-FDG PET/CT at two time points, prospectively: early image at 50-60 min and delayed image at 4-4.5 hours after the intravenous injection of $^{18}$F-FDG. Focally increased uptake lesions on early images but disappeared or shifted on delayed images defined a physiological uptake. For the differential evaluation of persistent focal uptake lesions on delayed images, colonoscopy and histopathologic examination were performed. SUVmax changes between early and delayed images were also compared. Results: Among the 132 patients, 153 lesions of focal colonic uptake were detected on early images of $^{18}$F-FDG PET/CT. Of these, 72 (47.1%) lesions were able to judge with physiological uptake because the focal increased uptake disappeared from delayed image. Among 81 lesions which was showed persistent increased uptake in delayed image, 61 (75.3%) lesions were confirmed as the malignant tumor and 14 (17.3%) lesions were confirmed as the benign lesions including adenoma and inflammatory disease. Remaining 6 (7.4%) lesions were confirmed as the physiological uptake because there was no particular lesion in the colonoscopy. In the malignant lesions, the calculated dual time point change for SUVmax ($\Delta$%SUVmax) was 20.8$\pm$18.7%, indicating a significant increase in SUVmax between the two point (p<0.01). In contrast, the change in SUVmax for the non-malignant lesions including benign lesions and physiological uptake was -13.7%$\pm$24.2%. For the differentiation of the malignant and non-malignant focal colonic uptake lesions, $\Delta$%SUVmax was the most effective parameter, and the cut-off value using -5% provided the best sensitivity, specificity, and accuracy. Conclusion: The dual time point $^{18}$F-FDG PET/CT imaging with SUVmax change evaluation could be an important noninvasive method for the differentiation of malignant and benign focal colonic uptake lesions including physiologic uptake.

Description of Range Control System in Space Center

  • Yun, Sek-Young;Choi,Yong-Tae;Lee, Hyo-Keun
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.53.2-53
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    • 2002
  • NARO Space Center is being developed as a national project for the Korea Space Development Program. Among the major missions of the Space Center, the Range Control System is the focal point for all command and control operation of the Space Center. The acquired data from the Tracking Stations and the on-site facilities is processed and distributed in the Control Center. Data processing or data fusion is needed for the exact tracking of the Launch Vehicle from several tracking systems. The first phase, which is the best telemetry source is selected among data streams that are received from each telemetry stations using some pre-defined criterion. Trajectory data and major telemetry parameters...

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The Hope of the Stroke Patients (뇌졸중환자의 희망)

  • 김이순
    • Journal of Korean Academy of Nursing
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    • v.27 no.1
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    • pp.212-227
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    • 1997
  • Cerebrovascular diseases in Korea is an important health problem since mortality and mobidity have been increased rapidly. It marked the 2nd cause of specific death rates in 1993. The stroke causes physical function disorder due to hemiparalysis and emotional disorder, and stroke patients experience helplessness, powerlessness. sense of alienation and loss of hope. These feelings make the rehabilitation difficult because they lose the will of life. The subjects of the study were seven citizens who live in Pusan, are over 50 years old and belong to low income-level. The data were collected from Jan. to Sep. 1995. The researcher as a caregiver and volunteer made confidence of them and asked for their agreement on the purpose of the study. The subjects expressed their experience as openheartedly as possible. The analysis of the data was made through the phenomenological analytic method suggested by Giorgi, which is as follows ; as an unit of description which include the subject' expressions and the researcher's observation, it is examined the theme that express the hope experience with the subject's language(underlining), and the focal meanings are identified. The focal meaning is the crystalization of the theme, which is written in the language of the researcher. After intergrating the focal meaning and make the situated structural description as the meaning of the hope experience identified on each subject's point. After intergrating the situated structural description and make the general structural description as the meaning of the hope experience identified on total subject's point then the systemizing of the structure of the hope experienced phenomena and the flowing of the conciousness was researched. The conclusions of this study was as follows : The ten sources of hope which the subjects experienced were sorted as under 〈mutual relations to others : spouse, children, relatives, fellow believer. health professioner. associate patient group〉, 〈spiritual dependence〉. 〈recovery of physical function〉. 〈rumination of the past life〉, 〈expectation of the future〉. 〈economic power〉, 〈belief〉, 〈ability〉. 〈spontaneous participation〉 and 〈recovery of roles〉. Their hope was spoken out by the following two kinds of linguistics. First. the hope was expressed in the affirmative expression as follows : 〈 to be dependable〉, 〈to make efforts〉, 〈to keep under control〉, 〈to desire〉, 〈to be pleasant〉, 〈to be peaceful〉, 〈to be grateful〉, 〈to give help〉, 〈self-confidence. Courage〉, 〈to be happy〉, 〈to satisfy oneself〉, 〈to share with others〉, 〈to understand〉 and 〈to be affected, be impressed〉 Second, the hope was expressed in the negative on pression as under : 〈to be distressed〉, 〈to be uneasy〉, 〈to be sorry, be unsatisfied〉 〈despair〉, 〈to abandon〉, 〈to be fearful〉, 〈to suffer〉, 〈to bear a burden〉 〈to be confused〉, 〈to be solitary〉, 〈chest trouble〉, 〈to feel heavy〉 〈grief〉, 〈to be daunted〉, 〈to get angry〉, 〈to be uncomfortable〉, 〈to have something regretable〉 and 〈to feel guilty〉. And their hope was expressed by the following four behavioral expressions : 〈physical sphere〉, 〈psychological sphere〉, 〈social support sphere〉 and 〈spiritual sphere〉. The reaction patterns of their hope experience appeared in the following 4 coping method : 〈conquest type〉, 〈dependence type〉, 〈adaptation type〉 and 〈fate type〉. Finally, in the hope structure the sense of certainty don't always coexict with the sense of uncertainty, When the stroke patients try to search for the best quality of life, the senses of certainty and uncertainty make a continual cyclic system in the hope structure.

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Analysis on the Measurement Results of the Focus Motor Position in MSC (Multi-Spectral Camera) on KOMPSAT - II

  • Heo, H.P.;Kong, J.P.;Kim, Y.S.;Park, J.E.;Chang, Y.J.;Lee, S.H.
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.372-375
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    • 2006
  • The MSC is a high resolution multi-spectral camera system which is mounted on the KOMPSAT-II satellite. The electro-optic camera system has a refocusing mechanism which can be used in-orbit by ground commands. By adjusting locations of some elements in optics, the system can be focused precisely. The focus mechanism in MSC is implemented with stepper motor and potentiometer. By reading the value of the potentiometer, rough position of the motor can be understood. The exact location of the motor can not be acquired because the information from the potentiometer can not be so accurate. However, before and after certain events of the satellite, like a satellite launch, the direction of the movement or order of the magnitude of the movement can be understood. In this paper, the trend analysis of the focus motor position during the ground test phase is introduced. This result can be used as basic information for the focus calibration after launch. By studying the long term trend, deviation from the best focal point can be understood. The positions of the focus motors after launch are also compared.

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A Study on the Evaluation and Improvement of Student Convenient Facilities at University Campuses, based on Universal Design Concept - Focused on the university campuses in Texas, U.S.A. - (유니버설디자인 개념에 의거한 대학내 학생편의시설 평가 및 개선방향에 대한 연구 - 미국 텍사스주를 중심으로 -)

  • Kim, Won-Pil
    • Journal of the Korean Institute of Educational Facilities
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    • v.21 no.3
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    • pp.19-28
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    • 2014
  • Student halls and their convenient facilities have been a focal point for various student activities at university campus. It has been for most of the student a place of unique memories and of attachment often associated with those good and bad school days. However, it is questionable whether these facilities are supportive and accessible for all of the students and other users including the handicapped. Therefore, based on the concept of UD(universal design) which was widely applied to U.S. institutions, this study intended to evaluate student hall facilities in U.S. and to provide an improvement direction for Korean UD application. For that purpose, four universities were selected for an in-depth analysis and 76 survey indices were utilized based on previous research. It was found that (1) design consideration without braille sign for VIP(visually impaired person) in student buildings can be differently approached with electronic devices; (2) the best demonstration of UD in student buildings can be seen in spacious flat pathway, easy access through ramp and wide entry area, necessary for people in wheel-chairs, but used by all, implying an increase of the ratio of public space; (3) one of the good UD features is an attractive physical environment rather than institutional appearance, in which they ultimately will support and completely adaptable at optimal levels by everyone; (4) consistent maintenance and management maximize the potential of UD principles and minimize physical limitations.

A Spatial Statistical Approach to Residential Differentiation (I): Developing a Spatial Separation Measure (거주지 분화에 대한 공간통계학적 접근 (I): 공간 분리성 측도의 개발)

  • Lee, Sang-Il
    • Journal of the Korean Geographical Society
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    • v.42 no.4
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    • pp.616-631
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    • 2007
  • Residential differentiation is an academic theme which has been given enormous attention in urban studies. This is due to the fact that residential segregation can be seen as one of the best indicators for socio-spatial dialectics occurring on urban space. Measuring how one population group is differentiated from the other group in terms of residential space has been a focal point in the residential segregation studies. The index of dissimilarity has been the most extensively used one. Despite its popularity, however, it has been accused of inability to capture the degree of spatial clustering that unevenly distributed population groups usually display. Further, the spatial indices of segregation which have been introduced to edify the problems of the index of dissimilarity also have some drawbacks: significance testing methods have never been provided; recent advances in spatial statistics have not been extensively exploited. Thus, the main purpose of the research is to devise a spatial separation measure which is expected to gauge not only how unevenly two population groups are distributed over urban space, but also how much the uneven distributions are spatially clustered (spatial dependence). The main results are as follows. First, a new measure is developed by integrating spatial association measures and spatial chi-square statistics. A significance testing method based on the generalized randomization test is also provided. Second, a case study of residential differentiation among groups by educational attainment in major Korean metropolitan cities clearly shows the applicability of the analytical framework presented in the paper.

How can the development of neighbourhood renewal strategies in Malaysia be informed by best practice and transferable lessons from developed countries (선진국 도시재생 사례비교를 통한 말레이시아 주거재생 전략의 모색)

  • Tin, Wan Jiun;Lee, Seok-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.469-486
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    • 2017
  • Economy-based urban redevelopment is the main priority in Malaysia, but has resulted in social problems such as gentrification, loss of heritage and identity, inequity, etc. Hence, it is crucial for the government to seek other alternatives rather than being solely reliant on urban redevelopment. Neighborhood renewal is a strategy involving the integration of redevelopment, rehabilitation, revitalization and preservation that aims to improve deprived areas using a more holistic approach. The aim of this paper is to review the neighborhood renewal policies in developed countries and to identify those elements that can be adopted in Malaysia. This study is conducted via a literature review. It was found that neighborhood renewal which integrates people-based, place-based and system-based policies highlights the importance of diversity, thereby aiming for resource optimization, community engagement and urban governance with the focal point of the fair, equity and systematic provision of resources. This paper concluded that neighborhood renewal in Malaysia should be initiated by locals with an emphasis on real local participation and a sustainable funding system. The government and local authorities should be observers rather than implementers.

Comparison of the Accuracy of Stereo Camera Calibration According to the Types of Checkerboards (체커보드의 유형에 따른 스테레오 카메라 캘리브레이션의 정확도 비교)

  • Kim, Eui Myoung;Kwon, Sang Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.38 no.6
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    • pp.511-519
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    • 2020
  • For camera calibration, a checkerboard is generally used to determine the principal point, focal length, and lens distortions. The checkerboard has a planar and three-dimensional shape, and camera calibration parameters are affected by the size of the checkerboard, the placement of the target, and the number of target points. In this study, the accuracies of the types of checkerboards were compared using checkpoints for stereo camera calibration, and the purpose of this study was to propose the best performance checkerboard. The checkerboard with large flat shape showed comparatively high accuracy through comparison with the check points. However, due to the size of the checkerboard, it was inconvenient to move and rotate, and there was a disadvantage in that it was difficult to shoot so that the target points could all appear in the stereo camera. The checkerboard, which was manufactured in a small size in a flat shape, was easy to move and rotate but had the lowest three-dimensional accuracy. The checkerboard with targets with height values had the hassle of having to determine the three-dimensional coordinates of the target points by using observation equipment for camera calibration, but it was small in size, convenient to move and rotate, and showed the highest three-dimensional accuracy.

Pareto Ratio and Inequality Level of Knowledge Sharing in Virtual Knowledge Collaboration: Analysis of Behaviors on Wikipedia (지식 공유의 파레토 비율 및 불평등 정도와 가상 지식 협업: 위키피디아 행위 데이터 분석)

  • Park, Hyun-Jung;Shin, Kyung-Shik
    • Journal of Intelligence and Information Systems
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    • v.20 no.3
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    • pp.19-43
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    • 2014
  • The Pareto principle, also known as the 80-20 rule, states that roughly 80% of the effects come from 20% of the causes for many events including natural phenomena. It has been recognized as a golden rule in business with a wide application of such discovery like 20 percent of customers resulting in 80 percent of total sales. On the other hand, the Long Tail theory, pointing out that "the trivial many" produces more value than "the vital few," has gained popularity in recent times with a tremendous reduction of distribution and inventory costs through the development of ICT(Information and Communication Technology). This study started with a view to illuminating how these two primary business paradigms-Pareto principle and Long Tail theory-relates to the success of virtual knowledge collaboration. The importance of virtual knowledge collaboration is soaring in this era of globalization and virtualization transcending geographical and temporal constraints. Many previous studies on knowledge sharing have focused on the factors to affect knowledge sharing, seeking to boost individual knowledge sharing and resolve the social dilemma caused from the fact that rational individuals are likely to rather consume than contribute knowledge. Knowledge collaboration can be defined as the creation of knowledge by not only sharing knowledge, but also by transforming and integrating such knowledge. In this perspective of knowledge collaboration, the relative distribution of knowledge sharing among participants can count as much as the absolute amounts of individual knowledge sharing. In particular, whether the more contribution of the upper 20 percent of participants in knowledge sharing will enhance the efficiency of overall knowledge collaboration is an issue of interest. This study deals with the effect of this sort of knowledge sharing distribution on the efficiency of knowledge collaboration and is extended to reflect the work characteristics. All analyses were conducted based on actual data instead of self-reported questionnaire surveys. More specifically, we analyzed the collaborative behaviors of editors of 2,978 English Wikipedia featured articles, which are the best quality grade of articles in English Wikipedia. We adopted Pareto ratio, the ratio of the number of knowledge contribution of the upper 20 percent of participants to the total number of knowledge contribution made by the total participants of an article group, to examine the effect of Pareto principle. In addition, Gini coefficient, which represents the inequality of income among a group of people, was applied to reveal the effect of inequality of knowledge contribution. Hypotheses were set up based on the assumption that the higher ratio of knowledge contribution by more highly motivated participants will lead to the higher collaboration efficiency, but if the ratio gets too high, the collaboration efficiency will be exacerbated because overall informational diversity is threatened and knowledge contribution of less motivated participants is intimidated. Cox regression models were formulated for each of the focal variables-Pareto ratio and Gini coefficient-with seven control variables such as the number of editors involved in an article, the average time length between successive edits of an article, the number of sections a featured article has, etc. The dependent variable of the Cox models is the time spent from article initiation to promotion to the featured article level, indicating the efficiency of knowledge collaboration. To examine whether the effects of the focal variables vary depending on the characteristics of a group task, we classified 2,978 featured articles into two categories: Academic and Non-academic. Academic articles refer to at least one paper published at an SCI, SSCI, A&HCI, or SCIE journal. We assumed that academic articles are more complex, entail more information processing and problem solving, and thus require more skill variety and expertise. The analysis results indicate the followings; First, Pareto ratio and inequality of knowledge sharing relates in a curvilinear fashion to the collaboration efficiency in an online community, promoting it to an optimal point and undermining it thereafter. Second, the curvilinear effect of Pareto ratio and inequality of knowledge sharing on the collaboration efficiency is more sensitive with a more academic task in an online community.