• Journal of Chest Surgery
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• 제22권6호
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• pp.1056-1060
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• 1989

Substernal goiter may be defined as any thyroid enlargement that has 50 to 100 % of its mass inferior to the thoracic inlet. Ectopic substernal goiters are rare, and most substernal gaiters arise from cervical thyroid gland. Fifteen to fifty percent of these patients are asymptomatic. Symptoms, when present, are usually the result of tracheal or esophageal compression. Symptoms are often positional. Standard chest roentgenograms are often diagnostic, but computed tomographic or radioactive iodine scans may be helpful. In symptomatic patients or those in whom explorations are undertaken for diagnostic purpose or exclude carcinoma, surgical removal is indicated. Although cervical thyroids with substernal extension may be safely and successfully removed through a cervical incision, primary substernal goiters by definition derive their blood supply from within the thorax and are better approached by splitting the sternum or through a posterolateral thoracotomy. Recently we experienced a child fist sized secondary posterior mediastinal goiter in 55-year old female. The mass was completely removed through right posterolateral thoracotomy without any complications. The postoperative courses were uneventful.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제13권3호
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• pp.217-233
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• 2009

The purpose of this study is to describe how dynamic geometry systems can be useful in proof activity; teaching sequences based on the use of dynamic geometry systems and to analyze the possible roles of dynamic geometry systems in both teaching and learning of proof. And also dynamic geometry environments can generate powerful interplay between empirical explorations and formal proofs. The point of this study was to show that how using dynamic geometry software can provide an opportunity to link between empirical and deductive reasoning, and how such software can be utilized to gain insight into a deductive argument.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.511-515
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• 2017

Various walking robot platforms have been developed to carry out missions such as explorations, pass of obstacle or inspections of dangerous environments. In this work, a four legs mechanism based on Jansen mechanism is developed, which can trace a certain line. In order to maximize the tracing speed, mechanism design is performed in multiple phases using m.sketch, EdisonDesign and Arduino programs. In design process, control of power path and optimization of the locus of legs(GL/GAC) are found to be most important. A prototype model is constructed and test run to check the validity of the design optimization.

• 대한수학교육학회지:학교수학
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• 제1권2호
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• pp.483-512
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• 1999

The purpose of the research was to investigate the patterns of student's mathematical thinking and behavior and describe the nature of difficulties the student underwent in trigonometry as the student conducted independent explorations within the interactive technology environment. Also, the research identified the connections among multiple representations and merits and shortcomings in using a graphic calculator as a tool. A take-based clinical interview procedure as the method for qualitative research was used to find the cognitive actions of the participant and his interactions with the graphic calculator. A case study report was written for the student. The researcher found that the student moved from operative stage, to constructive stage, to applicable stage of thinking. From Colgan; Graphing has significance both to mathematics and mathematics education in at least three ways since: * graphing represents an important technique, instrument and process in mathematics; * through ‘graphing’, per se, students can be said to be using one symbolic system to extend and acquire an understanding of another(e. g., trigonometric functions and their graphs). * graphing is propaedeutic to other, more advanced topics and concepts in mathematics.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제11권3호
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• pp.209-218
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• 2007

The purpose of this study is to create an interactive tool Geometry Player for geometric explorations. In designing this software, we referred to van Hiele's geometric learning theory of and Duval's cognitive comprehension theory of geometric figures. With Geometry Player, it is easy to construct and manipulate dynamic geometric figures. Teachers can easily present the dynamic process of geometric figures in class, and students can use it as a leaning tool to construct geometric concepts by themselves. It is hoped that Geometry Player can be a useful assistant for teachers and a nice partner for students. A brief introduction to Geometry Player and some application examples are included in this paper.

• 대한안전경영과학회지
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• 제10권4호
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• pp.315-325
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• 2008

This study examines the effect of brand personality on consumer's attitude. Previous research has suggested that the greater the congruity between consumer personalities and brand personalities, the greater the preference for the brand. However, empirical explorations of this hypothesis revealed that the congruity between consumer personalities and brand personalities is limitedly related, if ever, to the preference for the brand. It is partly because of the views of the previous researchers who considered human personality as a uni-dimensional concept, and partly because of the lack of consensus regarding what brand personality really is. This study examines the relative effect of brand personality on company image. In this study, brand personality is represented by the 'Big Five' factors - Sincerity, Excitement, Competence, Sophistication and Ruggedness - which were suggested by Jennifer Aaker.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.231-236
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• 2002

The understanding of underground geologic structures is of great importance for the surface and subsurface constructions, prevention of natural hazards such as land-slides and subsidence, and many other areas. To get the information on the geologic conditions, many of investigations such as geologic survey, geophysical explorations, testings on the physical properties of rocks, drilling tests and logging, and groundwater surveys are usually conducted, and tremendous data are collected accordingly. In general, however, these huge amount of data are interpreted in the individual areas only. If these data are analyzed collectively, much more information on the geologic conditions can be obtained. In this study, 3D visualization of borehole logging data is attempted. Borehole logging data are obtained at the urban subsidence area. To compare the 3D logging data with other geologic and geophysical data such as resistivity tomography data, interface module was developed. The 3D visualization of logging data and the comparison with other data can be helpful for the understanding of underground geologic structures.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.1084-1089
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• 2009

This paper presents the example of landslide triggered by the failure of earth retaining wall. Close examinations such as visual inspections and non-destructive testings revealed that the earth retaining wall does not have enough strength to resist active earth pressure and ground water pressure. This fact is proved to be a direct initiation of landslide. Numerical studies including slope stability analyses and seepage analyses were performed with material properties obtained by geophysical explorations and laboratory tests. The results of numerical studies show that the overturning of the earth retaining wall affects the slope stability, leading to landslide consequently.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권4호
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• pp.315-320
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• 2009

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application areas, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this paper, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggested based on experimental results obtained from simulations. The experimental results are presented to show the effectiveness of the behavior-based control using the proposed potential field generation technique.

• 지구물리와물리탐사
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• 제1권1호
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• pp.43-48
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• 1998

최근 들어 자원의 탐사분야나 지반조사를 위한 지하구조의 규명에 있어서 탄성파 토모그래피가 널리 사용되고 있다. 본 연구에서는 일반적으로 사용되는 파선을 이용한 주시 토모그래피에 Fresnel영역을 간단히 고려하는 알고리듬을 개발하였다. 개발된 알고리듬은 일반적인 주시 토모그래피에서와 같은 정도의 계산량이 소비되면서도 파동의 전파를 보다 잘 묘사할 수 있는 파동 토모그래피에서와 같은 효과를 거둘 수 있었다. 인공 합성자료와 현장자료에 적응한 결과 일반적인 파선 주시 토모그래피와 비교될만한 결과를 얻을 수 있었다.