• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.534-543
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• 2006

As the topology frequently varies, more cluster reconstructing is needed and also management overheads increase in the wireless ad hoc/sensor networks. In this paper, we propose a multi-hop clustering algorithm for wireless sensor network topology management using dynamic pre-clusterhead scheme to solve cluster reconstruction and load balancing problems. The proposed scheme uses weight map that is composed with power level and mobility, to choose pre-clusterhead and construct multi-hop cluster. A clusterhead has a weight map and threshold to hand over functions of clusterhead to pre-clusterhead. As a result of simulation, our algorithm can reduce overheads and provide more load balancing well. Moreover, our scheme can maintain the proper number of clusters and cluster members regardless of topology changes.

• Advances in materials Research
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• v.1 no.4
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• pp.311-347
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• 2012

Infections are caused due to the infiltration of tissue or organ space by infectious bacterial agents, among which Staphylococcus aureus bacteria are clinically most relevant. While current treatment modalities are in general quite effective, several bacterial strains exhibit high resistance to them, leading to complications and additional surgeries, thereby increasing the patient morbidity rates. Titanium dioxide is a celebrated photoactive material and has been utilized extensively in antibacterial functions, making it a leading infection mitigating agent. In view of the property amelioration in materials via nanofication, free-standing titania nanofibers (pure and nominally doped) and nanocoatings (on Ti and Ti6Al4V implants) were fabricated and evaluated to assess their efficacy to mitigate the viability and growth of S. aureus upon brief (30 s) activation by a portable hand-held infrared laser. In order to gauge the effect of exposure and its correlation with the antibacterial activities, both isolated (only titania substrate) and simultaneous (substrate submerged in the bacterial suspension) activations were performed. The bactericidal efficacy of the IR-activated $TiO_2$ nanocoatings was also tested against E. coli biofilms. Toxicity study was conducted to assess any potential harm to the tissue cells in the presence of photoactivated materials. These investigations showed that the photoactivated titania nanofibers caused greater than 97% bacterial necrosis of S. aureus. In the case of titania-coated Ti-implant surrogates, the bactericidal efficacy exceeded 90% in the case of pre-activation and was 100% in the case of simultaneous-activation. In addition to their high bactericidal efficacy against S. aureus, the benignity of titania nanofibers and nanocoatings towards tissue cells during in-vivo exposure was also demonstrated, making them safe for use in implant devices.

• Lingua Humanitatis
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• v.6
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• pp.213-240
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• 2004

This paper argues that Koguryo historically belonged to Korea based on the linguistic homogeneity among Koguryo, Sinra, and Paekche. The language of Koguryo shows the following four distinct properties from Chinese. First, Koguryo, Sinra, and Kara share a dual structure of national birth myths, and the directional vocabulary found in the countries also shows the evidence that the Korean people moved from North to South. Chinese, on the other hand, has no indication of these facts. Second, the place names in Koguryo shared the same properties with those of the countries in the Korean Peninsula at the same period, but were different from those of China. It is also noticeable that the national name of Korea, adopted from the national name of Koruryo, was announced to the world and that Korea has been acknowledged as our national name since then. The legitimate lineage of Koguryo > Parhay > Hu-Koguryo > Korea proves that Koguryo belonged to Korea historically, Third, the names of kings were very similar among the Three Kingdoms, but distinct from those of China. The names of kings were created on the basis of the sun as well as nature and human functions or activities like nuri (world), Piryu (originated from the name of a river), onjo (all over world), Chumong Hwar-bo (a person who is good at shooting), Paem-bo (a baby crawling like a snake), K\ulcornerchir-bo, Isa-bo, etc. This is a common characteristic among the Three Kingdoms, but clearly different from China. Fourth, the governmental names were very similar among the Three Kingdoms, but distinct from Chinese ones. These linguistic properties shared among the Koguryo, Packche, and Sinra are never accidental, but provide reliable evidence that the countries were founded by the Korean people. Koguryo, therefore, belonged to Korea historically.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.2
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• pp.86-92
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• 2007

This paper presents the development of fire-fighting and rescue robot for Outdoor Environment. In the procedure of this development, we follow Target Oriented Design (TOD) which is recognized as the systematic methodology to design a system by specifying the target clearly. For some real fire fighting tasks (e.g. tasks in shopping street and a market), narrow road make it difficult for existing fire engine to access the firing place. On the other hand, for dangerous tasks (e.g. gasoline station and a storehouse) the explosive materials make it impossible for fire-fighters to access the firing place. Moreover, the smoke and the high-temperature caused by fire make fire fighting difficult. In this situation, the solution is to develop the fire-fighting and rescue robot. TOD is performed firstly by analyzing the environment properties of fro place and the demanded tasks and the fire-fighting and rescue robot is manufactured. For safety, the fire fighting robot should be controlled by remote operation to keep the operator away from the fire, and the control system is divided into three parts: the robot controllers, controller for remote operating device and wireless communication system. We have selected and developed appropriate hardware and software for each part of control system with considering TOD. As a result, the fire-fighting robot functions correctly and the performance and usefulness of our control architecture is validated by successfully performing some fire-fighting tasks.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.1
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• pp.15-24
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• 2008

This paper proposes a scheme of global image contrast enhancement using local contrast improvement. Methods of global image contrast enhancement redistribute the image gray level distribution using histogram equalization without considering image properties, and cause the result image to include image pixels with excessive brightness. On the other hand, methods of the block-based local image contrast enhancement have blocking artifacts and a problem of eliminating important image features during an image process to reduce them. In order to solve these problems, the proposed method executes the block-based histogram equalization on temporary images that an input image is divided into various fixed-size blocks. And then it performs the global contrast enhancement by applying the global histogram equalization functions to the original input image. Since the proposed method selects the best histogram equalization function from temporary images that are improved by the block-based local image contrast enhancement, it has the advantages of both the local and global image contrast enhancement approaches.

• Bulletin of the Korean Chemical Society
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• v.26 no.3
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• pp.433-439
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• 2005

To gain further insight on the relationship between structure and functions of glutathione S-transferase (GST), the three tyrosine 108 mutants, Y108A, Y108F, and Y108W, of human GST P1-1 were expressed in Escherichia coli and purified to electrophoretic homogeneity by affinity chromatography on immobilized GSH. The substitution of Tyr 108 with alanine resulted in significant decrease of the GSH-conjugation activity and the GSH peroxidase activity, but approximately 63% increase of steroid isomerase activity toward ${\Delta}^5$–[androstene 3,17-dione. On the other hand, the substitution of Tyr 108 with phenylalanine resulted in decreases of $k_{cat}\;and\;k_{cat}/K_m{^{EPNP}}$ by 2 orders of magnitude, suggesting that Tyr 108 residue of hGSTP1-1 are considered to be important for the catalysis and the binding of the epoxide substrates. The substitution of Tyr 108 with tryptophan resulted in significant decreases of the specific activities toward EPNP, cumene hydroperoxide and ${\Delta}^5$–ndrostene 3,17-dione, but approximately 2-fold increase on the enzyme-catalyzed addition of GSH to DCNB. We conclude from these results that Tyr 108 in hGST P1-1 plays very different roles depending upon the nature of the electrophilic substrates.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.7
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• pp.1087-1099
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• 2010

This study explores the retail environment factors of the changes mentioned in the "Factors and Directions of the Change of the Apparel Retail Structure in Korea" (Part I) to understand the changes in apparel retail institutions. This study was done through a literature research method and the results are as follows. First, changing consumer needs and trends require extensive new products, a method to manufacture diverse products according to the market demand, and the necessity to manufacture based on trends in demand. This limits the role of mass production, which brought about more flexible manufacturing modes, scaled down manufacturing factories, promoted more cooperative subcontract relationships, and increased global sourcing which uses other companies at the most appropriate global venue. How to organize and use cooperative networks that benefit companies is the key to global competitiveness in the new era and the information technology developed around retail shops plays a key role. Consequently, the management of consumers and their information becomes critical and retail distribution functions become a key corporate function. In addition, it is difficult for small shops to introduce effective new technologies that encourage the growth of large companies. Second, apparel companies that use to benefit from scale merits based on the previous mass production system are now becoming effective by using economies of scale through mass retailing while shops are enlarging their sizes as a way to survive. On the other hand, inexpensive clothes become even more inexpensive while expensive ones become even more expensive, promoting polarization and diverse price ranges that widen consumer options.

• Journal of Korean Society of Disaster and Security
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• v.6 no.1
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• pp.1-8
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• 2013

Walking is one of human functions and has been the base of the development of human civilization. Walking ability had made the first village and urban pattern of the mankind. Cities had been constructed for pedestrian's convenience and happy life. But conventional cities have been crowded by the rapid increasing vehicles and population since material civilization had developed. On the other hand, pedestrian space has been neglected urban districts. Chose this study to suggest a direction for improvement by following the direction of the city characteristics and roadside pedestrian space. 1. Investigate the relationship and the significance and problems of pedestrian space by finding survey of the literature and discussion with those that affect the behavior of the pedestrian environment around. 2. For a comfortable pedestrian space on the improvement of the pedestrian area of space (physical and psychological) and gait characteristics, service levels and basic data. 3. Chose how to extract the most appropriate of the best alternatives presented several proposals based on the above survey of the literature data and field survey.

• Archives of design research
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• v.17 no.4
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• pp.347-352
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• 2004

The function of history is divided into two: justification and reflection. Justification confers causality on the consequences of history, and thereby putting emphasis on the inevitability of present. From the perspective of reflection, on the other hand, history is what is selected from several possibilities, and in this respect, present is not necessarily inevitable. The former is conservative; the latter, reformative. History, however, takes both of the functions. History reproduces a community by preserving memories of the community through a record, and leads to the evolution of a community through reflection. Emerged in the precess of industrialization, Korean design, despite its relatively short history, is witnessing a growing desire to prove its existence through history. While, it is also noteworthy that there is an increasing interest in looking at the history of Korean design from the perspective of reflection. I propose four propositions necessary to study of the history of Korean design. They are as follow; 1) History is interpretation; 2) The history of the institution should be overcome; 3) A simplifying progressive view of history should be restrained; 4) Foundation for study should be established.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.5
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• pp.1281-1287
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• 2003

In this research 2 sample compounds are made and analyzed in terms of the in vivo and in vitro effects on the ovariectomized rats. The 2 compounds are prescribed based on pathologic patterns of osteoporosis, and added calcium citrate from tuna bone powder. SG is for menopausal women(Type I osteoporosis) and GN is for senile men(Type II osteoporosis). Through these, SG manifested Significant effects on the T4, osteocalcin level, and through the histological changes of osteoid tissues and lipocytes. On the other hand GN showed significant increase on the biochemical markers of osteocalcin, TALP, even in histological features and bone mineral density and intensity of femur it showed meaningful changes. But In the results of RT-PCR on the IL-1β, IL-6, TNF α, there weren't coherent results with in vivo test, that is they were increased in the sample compound group than control group. These increase of bone resorption was seemed that those cytokines had the osteoclasts promote their own resorptive functions after fragments of bone tissues were increased in the cavity. And this clearance of inner fragments help the bone to strengthen its own substance. Putting together above facts, the sample compounds, SG and GN, made of tuna bone powder and herbal solutions are predicted that there would be pharmacological actions improving the osteoporosis initiated from the disorders of calcic absorption and increase of bone resorption. And GN has more effective actions than SG at least in the animal model.