• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.4
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• pp.282-288
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• 2014

Three-dimensional multimedia industry such as 3D TV, movie and broadcast has been developed vividly. For generating 3D contents with high quality, virtual auditory display, so called VAD, is being researched to offer more realistic experience to listeners. When people render VAD using headphones or two speakers, head-related transfer function(HRTF) plays a key role. The best solution is measuring all individuals' HRTFs, but it is hard to measure all listeners' HRTFs. To overcome this difficulty, many research groups have tried to construct their own measurement system and to build HRTF databases. However, some of them have not enough subjects or spatial resolution and they are mainly focused on Caucasian. There exists difference between Korean and Caucasian in a view of physical features. In other words, if Koreans hear three-dimensional sound rendered by HRTF database based on Caucasian, performance might be hindered. To verify this possibility and remedy the drawbacks, construction of new HRTF database aimed at Korean is needed. Therefore, our laboratory built HRTF measurement system which can measure HRTF of three-dimensional space with dense spatial resolution. With this system, 55 Korean males and 45 females' HRTFs were measured and Korean HRTF database was built based on these data.

• Journal of Chest Surgery
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• v.21 no.3
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• pp.454-461
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• 1988

Myasthenia gravis is a functional neuromuscular disorder with characteristic voluntary muscle weakness. The role of thymus in pathogenesis of this disorder has become apparent that thymectomy in treatment has gained acceptance. Between January 1976 and June 1987, twenty patients underwent thymectomy for myasthenia gravis at the Department of Thoracic and Cardiovascular Surgery, College of Medicine, Korea University. A clinical study that is focused on the factors affecting the operative results was analyzed and the following results were obtained. Among the 20 patients, male to female ratio was 8:12 and the age of onset was ranged from 3 years to 67 years. The chief complaints in order of frequency were as follows; ocular symptoms such as ptosis and diplopia[7 cases], general weakness[4 cases], swallowing difficulty[3 cases], dyspnea[3 cases], dysphasia[1 case], headache[1 case] and dizziness[1 case]. The severity of disease was classified by modified Osserman`s method that Group IIa was 8 cases, Group IIb; 7 cases, Group IIc; 3 cases and Group I; 2 cases. In histopathology of thymus, the most frequent finding was hyperplasia[11 cases] followed by thymoma[4 cases], normal tissue[3 cases] and malignant` thymoma[2 cases]. There were two cases of postoperative complications; one case was wound infection and the other was mediastinitis. One case of malignant thymoma died due to respiratory failure with pulmonary metastasis. There was 16 cases[80%] of improvement after thymectomy as follows; complete remission was 4 cases[20%], marked improvement was 9 cases[45%] and subjective improvement only was 3 cases[15%]. The effect of severity and duration of disease on operative result has statistically significant. The effect of thymus histopathology on operative result was not statistically significant. But there were comparable results between thymoma cases and non-thymoma cases.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.212-220
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• 2013

This study analyzed the effect of fairness of personnel management systems of public organizations on job satisfaction and job performance. For hits, satisfaction, problems, and improvements of personnel management systems were investigated targeting 4 personnel management systems which are being operated in Chungcheongnam-do and analyzed the correlations between job satisfaction and job performance with it. Personnel fairness has the positive effect on job satisfaction and performance of public servants. When personnel management is done by considering career, degrees of work difficulty, and efforts, job satisfaction and performance can increase. This shows that fair personnel management plays the important role in organizations and employees' morale. As the various personnel management systems are being operated in Chungcheongnam-do, the fact that personnel management of public servants is done according to objective evaluation materials and procedures with the same principles should be recognized.

• Journal of Educational Research in Mathematics
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• v.14 no.3
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• pp.305-325
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• 2004

This study is on the teaching-learning of parameter concept in secondary school mathematics. In our school mathematics curriculum, parameter concept is explicitly presented at high school mathematics textbook. But student have difficulty in understanding parameter concept because this concept is implicitly used in the textbook from 7-grade mathematics. Moreover, it is true that mathematics teacher give a little attention to student's understanding of parameter con- cept. In this study, we analyzed concept definition of parameter and the extension of parameter on the basis of preceding research, our mathematical curriculum, mathematical dictionaries. After that, we concluded that parameter is explicitly called in t where x= f(t), y= g(t) and parameter is implicitly treated in the learning of relation between quantities in our mathematical curriculum. We pointed to the importance of parameter concept in the successful learning of school algebra. Specially, when the level of algebra is in the learning of relation between quantities, parameter is the key concept for understanding and representing of families of equations or functions. In mathematics class, students have opportunity to reflect that what the role of each variable(parameter, dependent variable, independent variable etc.) is, and where the information which determines it comes from. It is for mathematical communications as well as learning school algebra. Therefore, mathematics teacher's didactical attention is more needed to student have a good concept image of parameter before they learn explicitly its concept definition.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.181-189
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• 2004

The purpose of this study was to investigate the effects of sleep/wake behavior for shift workers in the iron and steel industry using wrist actigraph for 59 male workers on a continuous full-day three-team three-shift system of backward rotation including on-duty and off-duty periods. The wrist actigraph data were recorded for 15 days (l shift cycle) for each subject. The sleep length at home during night shift decreased significantly as compared to the morning or evening shifts. The night shift nap length increased significantly in all sections as compared to the morning or evening shifts. The nap length in the Steel Manufacturing Process and Rolling Process during night shift decreased significantly as compared to the Machine Maintenance Section, the Forwarding of Products Section, and the Field Management Section. However, the sleep length at home while off-duty period increased significantly. The percentage of nap length during night shift in the Rolling Process, Steel Manufacture Process, and the other three types of jobs was 16.0%, 20.4%, and about 50.0%, respectively. The nap length during night shift for the above 50 year olds increased significantly as compared to the below 50 year olds. Finally, we discussed the role of nap-taking during the burden on night shift workers and the increased difficulty in continuing their job.

• Journal of Microbiology and Biotechnology
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• v.24 no.8
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• pp.1015-1025
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• 2014

Microorganisms that live in the rhizosphere play a pivotal role in the functioning and maintenance of soil ecosystems. The study of rhizospheric cyanobacteria has been hampered by the difficulty to culture and maintain them in the laboratory. The present work investigated the production of the plant hormone indole-3-acetic acid (IAA) and the potential of biofilm formation on the rhizoplane of pea plants by two cyanobacterial strains, isolated from rice rhizosphere. The unicellular cyanobacteria Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 that were isolated from a rice rhizosphere, were investigated. Production of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 was measured under experimental conditions (pH and light). The bioactivity of the cyanobacterial auxin was demonstrated through the alteration of the rooting pattern of Pisum sativum seedlings. The increase in the concentration of L-tryptophan and the time that this amino acid was present in the medium resulted in a significant enhancement of the synthesis of IAA (r > 0.900 at p = 0.01). There was also a significant correlation between the concentration of IAA in the supernatant of the cyanobacteria cultures and the root length and number of the pea seedlings. Observations made by confocal laser scanning microscopy revealed the presence of cyanobacteria on the surface of the roots and also provided evidence for the penetration of the cyanobacteria in the endorhizosphere. We show that the synthesis of IAA by Chroococcidiopsis sp. MMG-5 and Synechocystis sp. MMG-8 occurs under different environmental conditions and that the auxin is important for the development of the seedling roots and for establishing an intimate symbiosis between cyanobacteria and host plants.

• Journal of KIISE:Information Networking
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• v.34 no.2
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• pp.88-99
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• 2007

P2P systems are distributed data sharing systems, and each node in them plays the role of client as well as server. There are several studies using Distributed Hash Table, such as Chord, CAN, Tapestry, Pastry, but these systems don't consider the physical latency, therefore they have a weakness of difficulty to guarantee stable performance. To improve this problem, we present the TP2P system. This system is a self-organizing hierarchical overlay system and it uses Chord routing mechanism for lookup data. This system is organized by several subnets, each subnet is organized by physically close nodes, and global network organized by all nodes. In each subnet, one node finds a data, it saves in a node in the subnet, therefore it has higher probability to reduce physical lookup latency than Chord system. And each node has global information of some nodes in its subnet, and it is used to lookup data, therefore the number of hops decrease about 25% as well as the physical lookup latecy are reduced.

• Journal of the Korea Computer Industry Society
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• v.8 no.4
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• pp.295-302
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• 2007

Because Mobile computing uses radio transfer communications division carrying along information terminal, internet link computer and information technology of human body effectively, when, where, who, can offer role that is center enemy of available modern technology moving and reconsider new technology to physiological sounding, and reconstruct creatively. Specially, can offer possibility that can intervene in process that motive living body change before military register symptoms are developed of disease on silver society. But, much parameters data processing, standard anger of data of that is vague. same time collection of data can lift difficulty etc.. Therefore, this research excludes time limitation constituent inflecting Mobile computing, and result that analysis experiments because is proper and Mobile nerve mechanical code Tuesday that do with bioelectricity signal method select and embody system by access that become correct analysis, is becomes model of living body signal Mobile analysis device, and person could apply Mobile living body measuring device m-HSS (mobile-Hardware-software system) that measuring is possible by scientific access.

• Journal of Korean Medical classics
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• v.25 no.3
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• pp.23-38
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• 2012

Objective : Ankylosing Spodylitis(AS) is a chronic inflammatory disease that is notorious for its difficulty to cure. This study aims to interpret the mechanism of AS in the Traditional Korean Medical(TKM) perspective, and to understand the role of the spine. Method : Clinical manifestations of AS, epidemiological data and clinical cases were interpreted by traditional methodology. Result : The young age group of patients suffering from this condition suggests that the cause of this condition is not solely linked to deficiency of the Kidney[腎], which is a general cause for bone disease. Its symptoms are linked to obstruction in the upper body, which results in disturbance of Jeong(精) collection in the lower body. Based on other accompanying symptoms, together with its character as an autoimmune disease, a strong link to the spirit of the heart[心神] can be suggested. Conclusion : AS is closely linked not only to essence of kidney[腎陰], but to the spirit of the heart[心神] as well. From the TKM analysis of the spine, we can understand it as the basic pathway for the fundamental Gi(氣) circulation.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.356-367
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• 2011

In this paper, we proposed a new car engine sealing inspection system based on image processing and understanding. The car engine sealing inspection plays very important role for protecting leakage caused by inappropriate sealing, which is a crucial point for productivity of car engines. The proposed inspection system has been aimed to enhance the previously proposed sealing inspection systems based on image processing, which have high computation complexity and low performance for correctly inspecting some contamination by oil with similar color with that of sealing. Moreover, the previously proposed system has a difficulty in installing the camera system on the sealing machine. The proposed system considers a difference of images before and after sealing obtained from one static camera. By utilizing a difference of images, the proposed system shows very robust performance using a proposed simple depth checking algorithm for some contamination cases by oil with similar color with that of sealing and the total inspection system is simple and cheap to implement. According to the experiments conducted in a real car product line, the proposed inspection system shows better inspection performance and needs smaller implementation cost than three other previously proposed system working in current car sealing inspection systems.