• Journal of Chest Surgery
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• v.39 no.8 s.265
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• pp.655-658
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• 2006

Mesothelial cyst is a rare mediastinal tumor and usually presents in the right cardiophrenic angle. However, it sometimes occurs in atypical locations and it’s locating in the posterior mediastinum, especially, is very rare. A large cystic mass of the posterior mediastinum between pericardium and vertebral body was incidentally recognized in a patient of a 30-year-old woman admitted due to traffic accident. Even though it was very large in size measuring 18 em at longest diameter and is extending mainly to the left pleural cavity, she had no symptomatic complaints. Complete excision was performed through video-assisted thoracoscopic surgery with a additional small working window, which was necessary for dissecting the deepest point to the right pleural cavity. She is in good condition without recurrence on long-term follow-up.

• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.617-629
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• 2012

This study aims to find out critical areas of a soil loss and propose feasible measures to reduce the water quality deterioration by a soil lose. As a study area, the So-ok stream catchment locating at the upper area of Daecheong Reservoir is selected and intensive field observation was carried out. RUSLE model is applied to assess the impact of the pollution migration by a soil ross from the critical areas during storms on the water quality of Chusori embayment. As results, total amount of the soil ross assessed against to the critical area on which major type of land use is a orchard for fruits is 54.3 ton/ha/yr and that of an abandoned mine site is about 200 ton/ha/year. In particular as effective measures, a plantation of an appropriate species of fruit trees and an application of ecologic restoration schemes are proposed against to the orchard and the abandoned mine site, respectively.

• School Mathematics
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• v.5 no.1
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• pp.43-58
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• 2003

This study intends to compare the structure of contents and the way of developing concepts in mathematics textbooks of south and those of north Korea. After thorough investigations of the textbooks from south and north Korea, the following three characteristics were identified. First, the mathematics textbooks of south Korea tends to spread out contents across several grades, while those of north Korea have a tendency of centralization in terms of locating contents Second, in the textbooks of South Korea, mathematics concepts are permeated through real world situations, and students gradually acquire those concepts mostly through activities. This is different from the approach of the north Korean textbooks in which various problems play a key role in explaining concepts. Third, the main strategy of introducing contents in the textbooks of south and that of north Korea corresponds to 'guidance' and 'explanation' respectively. Exploratory questions leading to the concepts are more emphasized in the textbooks of south Korea, on the other hand, meaningful explanations play an important role in the textbooks of north Korea.

• Smart Structures and Systems
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• v.4 no.3
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• pp.343-365
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• 2008

In this study, the frequency domain method which utilizes the evaluation of changes in the structural mode shape is adopted to identify regions which contain localized damages. Frequency response function (FRF) values corresponding to the modal frequency, analogous to the mode shape coefficients, are used since change in natural frequency of the system is usually insignificant for localized damage. This method requires only few sensors to obtain the dynamic response of the structure at specific locations to determine the FRF via fast-Fourier transform (FFT). Numerical examples of an aluminum plate, which includes damages of varying severity, locations and combinations of multiple locations, are presented to demonstrate the feasibility of the method. An experimental verification of the method is also done using an aluminum plate with two different degrees of damage, namely a half-through notch and a through notch. The inconsistency in attaining the FRF values for practical applications due to varying impact load may be overcome via statistical averaging, although large variations in the loading in terms of the contact duration should still be avoided. Nonetheless, this method needs special attention when the damages induce notable changes in the modal frequency, such as when the damages are of high severity or cover more extensive area or near the boundary where the support condition is modified. This is largely due to the significant decrease in the frequency term compared to the increase in the vibration amplitude. For practical reasons such as the use of limited number of sensors and to facilitate automation, extending the resolution of this method of identification may not be efficient. Hence, methods based on wave propagation can be employed as a complement on the isolated region to provide an accurate localization as well as to trace the geometry of the damage.

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.477-485
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• 2020

Finite element (FE) model based structural damage detection (SDD) methods play vital roles in effectively locating and quantifying structural damages. Among these methods, structural model updating should be conducted before SDD to obtain benchmark models of real structures. However, the characteristics of updating parameters are not reasonably considered in existing studies. Inspired by the l_∞ norm regularization, a novel anti-sparse representation method is proposed for structural model updating in this study. Based on sensitivity analysis, both frequencies and mode shapes are used to define an objective function at first. Then, by adding l_∞ norm penalty, an optimization problem is established for structural model updating. As a result, the optimization problem can be solved by the fast iterative shrinkage thresholding algorithm (FISTA). Moreover, comparative studies with classical regularization strategy, i.e. the l₂ norm regularization method, are conducted as well. To intuitively illustrate the effectiveness of the proposed method, a 2-DOF spring-mass model is taken as an example in numerical simulations. The updating results show that the proposed method has a good robustness to measurement noises. Finally, to further verify the applicability of the proposed method, a six-storey aluminum alloy frame is designed and fabricated in laboratory. The added mass on each storey is taken as updating parameter. The updating results provide a good agreement with the true values, which indicates that the proposed method can effectively update the model parameters with a high accuracy.

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.415-424
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• 2020

Recently, many structural damage detection (SDD) methods have been proposed to monitor the safety of structures. As an important modal parameter, mode shape has been widely used in SDD, and the difference of vectors was adopted based on sensitivity analysis and mode shapes in the existing studies. However, amplitudes of mode shapes in different measured points are relative values. Therefore, the difference of mode shapes will be influenced by their amplitudes, and the SDD results may be inaccurate. Focus on this deficiency, a multi-strategy SDD method is proposed based on the included angle of vectors and sparse regularization in this study. Firstly, inspired by modal assurance criterion (MAC), a relationship between mode shapes and changes in damage coefficients is established based on the included angle of vectors. Then, frequencies are introduced for multi-strategy SDD by a weighted coefficient. Meanwhile, sparse regularization is applied to improve the ill-posedness of the SDD problem. As a result, a novel convex optimization problem is proposed for effective SDD. To evaluate the effectiveness of the proposed method, numerical simulations in a planar truss and experimental studies in a six-story aluminum alloy frame in laboratory are conducted. The identified results indicate that the proposed method can effectively reduce the influence of noises, and it has good ability in locating structural damages and quantifying damage degrees.

• Journal of Korean Medical classics
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• v.13 no.2 s.17
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• pp.86-95
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• 2000

Following is the result through translating. studying, and analyzing San Zhi Shan(三指禪), the book worked by Zhou Xue Ting(周學霆). 1. The chapter of Mai Xue Yuan Liu(脈學源流) explains the Xiang Shu Xue(象數學) viewpoint, the part that pulse is based on Lu guan(律管). 2. The chapter of Liu Bu Mai Jie(六部脈解) explains that emphasizing Shen(神) through understanding the shape of pulse(脈象) is more important than the locating the area of the shape of pulse(脈象). 3. The chapter of Zuo Xin Tan Zhong Can Dan Shen Xiao Chang You Fei Xiang Zhong Pi Wei Ming Da Chang Bian(左心膽中肝膽腎小腸 右肺胸中脾胃命大腸辨) exhibits the different view about the position of pulse from Li Shi Zhen(李時珍)'s. the chapter in which Zhou(周) arranges Heart{\cdot}Small\;Intestine{\cdot}Liver{\cdot}Gall\;Bladder{\cdot}Kidneys{\cdot}and$ Bladcler(心 小腸 肝 膽 腎 膀胱) in left hand and $Lungs{\cdot}Large{\cdot}Intestine{\cdot}Spleen{\cdot}Stomach{\cdot}Kidney{\cdot}and$ The gate of Vitality(肺 大腸 脾 胃 腎 命門) in right hand. From the above results, I'm sure that San Zhi Shan(三指禪)which has headed down to descendants as the special book about the study of pulse has developed the theory of pulse. Therefore I expect that the more profound study about this will be going on.

• Journal of Advanced Navigation Technology
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• v.24 no.5
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• pp.343-347
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• 2020

This paper presents the development of a software for tracking the location of objects in the water and for creating a three-dimensional hull map. The objective of this software, as a software for underwater hull cleaning robot, is to map the location of underwater hull cleaning robot and to locate the position of sensor by identifying the shaded area of acoustic communication. For the software designed for mapping the location of cleaning robot in the water, the height and intensity were applied as variables for underwater ultrasonic communication. The software for creating a three-dimensional hull was developed by OpenGL using scanned lines from a blueprint of a ship. This software can help identifying the location of underwater hull cleaning robot without actual visibility and can be used to maintain a stable communication status by locating the position of sensor by easily spotting the shaded area of acoustic communication caused by the curved area of the bottom of the ship.

• Korean Journal of Cognitive Science
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• v.10 no.1
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• pp.57-66
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• 1999

We believe that science experiments in a laboratory are essential for science education. Scientific experiments begin with situations set by selecting and locating tools and reagents. and by proper experimental behavior, and thereafter situations are changed by natural laws and intermediate experimental behavior. While scientists and students do experiments, they build a cognitive model internally, do causal reasoning on the model to derive system behavior, and then learn scientific truth. We suggest not only a representation method for a 2-dimentional model and for ontological entities necessary in causal reasoning, but also an inferencing method to derive behavior. Chemistry experiments are chosen for the implementation. For the ontological entities, we consider experimental tools, reagents and their heirarchical structures, physics and chemistry natural laws, and functional abstraction knowledge. In order to show the usefulness of our methods, we have developed a program, called ACUArtificial Chemistry Laboratory), which provides an experiment environment where students can do non-predetermined experiments, and shows experiment려 system behavior similar to what happens in the same situation in a real world and descriptions about why it happens.

• Journal of Korean Library and Information Science Society
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• v.36 no.3
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• pp.213-231
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• 2005

Yeonhaengrok is a document recorded by one member of the envoy sent to the China from 17 to 19 century. Ik-mo Lee, a member of the envoy, wrote a full explanation of the visit from Nov. 24 1796 to Mar. 7 1797 in his writing $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$. $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$, which is omitted in the complete collection of $\ulcorner$Yeonhaengrok${\lrcorner}$, has been newly found at the Family of Suwon Baek's house locating at the Sanggum Vil., Yongsan Town, Jangheung County of Chonnam Province. $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$ contains an historical meaning that it is an official record of the official envoy that was sent first after the Injong's enthronement in China. This study observed the bibliographical features of $\ulcorner$Byongjin Yeonhaengrok${\lrcorner}$, the time of the transcription, the progress of receiving by the Suwon Baek family. And certified the details of the Byongjin envoy, going and returning between Hanyang and Beijing, staying schedules of the envoy in Beijing.