• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.3
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• pp.1-7
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• 2010

Cognitive Radio, which adaptively utilizes the vacant licensed spectrum band, is considered as an effective way to alleviate the scarcity of spectrum resource shortage. In order to guarantee the non-interference transmission of primary system, spectrum sensing, especially in quiet period, is proposed. However, it is insufficient to avoid the unacceptable interference caused by Cognitive Radios, because the primary user may appear anytime that is unpredictable. In this paper, we address the deficiency of conventional spectrum sensing and propose a novel Cognitive Radio receiver structure with monitoring function block to detect the appearance of primary user in a real-time manner. Simulations prove that the proposed eigenvalue based detection method together with the two-threshold decision procedure performs properly.

• Korean Journal of Veterinary Research
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• v.49 no.2
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• pp.141-147
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• 2009

In Korea, burial is the most common method of disposing animal carcasses culled due to brucellosis infection. However, burial has many disadvantages such as shortage of appropriate burial sites, possibile pollution of ground water supply, and negative view of the public. In this study, we have reviewed 3 legal methods for disposing bovine carcasses, which are burial, incineration, and rendering. We also described the overall process, advantages and disadvantages, and required costs for each method. About 75% of bovine brucellosis outbreak farms had less than 3 reactors, and in our study, rendering required the least amount of cost for farms with a small number of reactors (1-3 heads). Our findings suggest that the use of rendering should be encouraged for farms with bovine brucellosis and other methods considered only if rendering is inappropriate.

• Journal of the Korean Society for Library and Information Science
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• v.54 no.2
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• pp.105-125
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• 2020

This study attempts to identify the influence factors on the numbers of visitors and reference room users of public libraries through log-log multiple regression models, using the Korean National Libraries Statistical Data 2018. The fact found is summarized as follows; Even though books collection and seating capacities might be the most important factors in attraction of visitors and reference room users to public libraries in the past when the storage and propagation of knowledge and information was the top function of public libraries, very various and compound factors such as cultural or lifetime education programs, library operation, and user activities have an effect on inducing people to visit and use public libraries at present. This means that these days, public libraries are being transformed into some kinds of comprehensive cultural center where software elements such as cultural programs, user education, events, budget, membership, opening days, building style and age, and group activities rather than hardware elements such as books, literature material, and facilities constitute their essential parts in connection with visitor and user induction.

• Journal of the Korean association of regional geographers
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• v.14 no.5
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• pp.507-520
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• 2008

The two districts, 'Xita' and 'Manrong' in Shenyang City, the cases of this study, form ethnic enclave economies revolving around small business enterprises run by Korean Chinese. This ethnic enclave economy appeared as Korean Chinese came to have 'double ethnic resources'-Korean Chinese and Koreans living in China, and to play the role of middlemen. This was helped by the Chinese government's encouragement(to attract the capitals of South Korea), and the experiences of Korean Chinese who had played in South Korea. This 'double ethnic enclave economy' has put Korean Chinese in a position where they cooperate with Koreans in China on the one hand, but are forced to compete with them on the other. For the development of a Chinese Korean economy, therefore, it is needed to enhance the cooperation with Koreans living in China within the ethnic enclave economies and at the same time to increase economic activities outside of the enclave economy.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.328-338
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• 2018

Central Asia (Uzbekistan, Kazakhstan, Kyrgyzstan) is a hot and arid continental climate, with most areas (68%) consisting of barren vegetation, desert, and meadows. The main agricultural areas for crop production include irrigated farmland, non-irrigated farmland, grassland, prairie and mountain. We are experiencing climate change with recent climate variability increasing. Agriculture is one of major economic sectors and provides a means of livings for the rural population of Central Asia, especially the poor. In the past two decades, Central Asia has experienced a high population growth rate, with Kazakhstan at 16.8%, Uzbekistan at 34.5% and Kyrgyzstan at 28.4%. As a major industry, Kazakhstan has the largest share of exports of agricultural products followed by petroleum, mineral resources, steel, and chemicals. Uzbekistan is the fifth largest cotton exporter as well as the sixth largest cotton producer in the world. Kyrgyzstan exports ores, stones, cultured pearls, and minerals. These three countries are rich in mineral resources, agricultural products, and energy resources. However, not only do they have difficulties in economic development due to the weakness of logistics and industrial infrastructure, but they also have imperceptible cooperation and investment among countries due to insufficient research and development. Through this study, we will investigate national outlook, economic indicators, major agricultural products, import and export status, and agricultural technology cooperation status, and study how Korean agricultural industry advances into these countries through SWOT analysis. Through this, we hope to contribute to the basic data of Central Asian studies and cooperation and investment in agriculture in each country. In addition, in order to increase cooperative exchange and investment in these countries, we will prepare a Central Asia logistics hub for the rapidly changing interKorean railroad era.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.490-497
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• 2007

Odontoma is defined as a benign odontogenic tumor containing enamel, dentin as well as cementum and constitued 22% of all odontogenic tumors. Although the lesions are commonly asymptomatic, they may be discovered routine radiographic examination. Odontomas often cause disturbances in the eruption of teeth such as, impaction or delayed eruption, retention of primary teeth, or abnomalities in the position of the teeth such as tipping or displacement of adjacent teeth. Radiologically, odontomas manifest as a dense radiopaque lesion surrounded by a thin radiotransparent halo. However, in some cases, radiopacity was not quite clear and images of the teeth shadowed very tiny odontomas. And at early development stages of odontoma, calcification remains immature and is difficult to diagnose on radiographs. This suggests that when delayed eruption of the teeth is found, periapical radiographs should be taken to clarify whether any small area of radiopaque material exists. This case report shows tiny odontomas involving an impacted tooth and crowding and we remove the tiny odontoma surgically.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.667-674
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• 2008

In this paper, operational problems of Busan Port and competitiveness deciding factors are analyzed by field data research and interview with employees in shipping companies and terminal operation companies. In the analysis, the problems Busan Port currently has are identified as follows: 1) low price competitiveness, 2) Lack of new port back facilities and connecting transportion system 3) Lack of operation ability of container terminal 4) Inefficient pour labor supply system. In order to strengthen the competitiveness and leap up to a hub port in North East Asia, Busan port is investigated to enhance below requirements. 1) Hiring more equipment and increase productivity in terminal 2) Integrating terminal operation companies to react maximization of vessel 3) Maintaining cost advantages 4)Proactively inviting global carriers to participate in the terminal operation 5)Making business environment for Global Terminal Operator to participate in the terminal operation in order to take advantage of their global marketing power.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.144-151
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• 2005

Erosion is believed to be the predominant cause of teeth wear in children and young adults, although there will at ways be a contribution from attrition and abrasion. The pH of cola is known to be low and have, therefore, been implicated in the increasing incidence of erosion. The aim of present study was to evaluate the effect of cola on the progression of erosive demineralization in human enamel using demineralization model in vitro. Six groups of human enamel slap were immersed(5 min each bath) in fresh cola, with immersions taking place with or without agitation, and under 3 regimes of frequency intake(low intake, 1 immersion/day; medium, 5/day; high, 10/day). Quantitative assessments of surface erosion were done over an 8-day interval using surface microhardness testing. 1. The average pH of cola was 2.5, which was acidic enough to cause tooth erosion. 2. All the enamel specimen exposed to cola showed erosion like lesions and surface hardness decreased in proportion to the length of immersion (p<0.05). 3. The surface hardness of enamel decreased in proportion to the frequency of immersion (p<0.05). 4. Increased degassing from the drink by gitation accelerated the enamel softening compared with those without agitation.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.127-135
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• 2008

The purpose of study was to evaluate the amount and the accuracy of oral health care information in childcare books. Thirty five Korean childcare books were selected and analyzed. Twenty eight(80%) books contained information about oral health care and the average amount was 4.8 pages(1.2%). Among those books, the book that a dentist wrote the content and the book that was given advice from a dentist were one(3.6%) and one(3.6%), respectively. The eruption time and sequence of deciduous teeth and the toothbrushing method were described in 96.4% and 82.1% of those books. The books which contained the other oral health care contents were less than half. Three(10.7%) books contained inaccurate contents. Therefore, dentist should give oral health care information to parents more actively. And it seemed to be necessary to study other information sources like magazines, TV programs, internet resources, and education programs by health centers and department of obsterics.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.352-358
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• 2020

Glanzmann's thrombasthenia (GT) is a rare, autosomal recessive inherited congenital disorder, characterized by impaired blood coagulation due to platelet dysfunction. It was first reported by the pediatrician Glanzmann in 1918. GT affects both males and females, and it is more common in regions of the Middle East, India, and France, where intermarriage is common. It has an incidence of about 1 in 1,000,000 people. In South Korea, according to the Division of Rare Diseases, Korea Centers for Disease Control and Prevention, around 200 cases have been reported in 2018. Clinical symptoms include petechia, ecchymosis, epistaxis, and gingival bleeding. The spontaneous loss of deciduous teeth can result in excessive bleeding with that blood transfusion should be considered. Preventing hemorrhages and hemostasis are most important factors in dental treatment. Local bleeding can be controlled by compression, but platelet transfusion can be required by prolonged bleeding. Pediatric dentists can minimize the gingival bleeding by control of the oral hygiene to prevent gingivitis and dental caries. The importance of oral hygiene and periodic recall check-up should be emphasized. During dental treatment, the examination and the treatment plan of patient should be modified to prevention of hemorrhages carefully. A 6-year-old girl with GT was referred for the treatment of dental caries, and resin restoration was performed under nitrous oxide inhalation sedation. After treatment, compression was required for the bleeding control.