• Korea journal of population studies
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• v.18 no.2
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• pp.70-97
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• 1995

The main purpose of this paper is to analyze the trend of urbanization and population distribution in North Korea. Although North Korean data lack comparable details, attention has been given to the comparison of urban system between North and South Korea. In North Korea, the pace of urbanization was most rapid just after the Korean War, from 1954 to 1960. However, the pace slowed down markedly in the early 1970s and has remained sluggish since then. North Korea is currently much less urbanized than South Korea. As specific features of urbanization in North Korea, emergence of new cities along inland borders, prominence of intermediate-sized cities, and sudden population growth of major cities due to boundary expansion are stressed. Available demographic data also indicate an overwhelming primacy of Pyongyang Municipality in the urban system, and rapid growth of satellite cities in the west-central region. It appears that, in North Korea, urbanization process has been a product of the government's development policies rather than individual's socioeconomic motivation to migrate urbanward. Finally, migration issues after unification of the Korean Peninsula and related problems are discussed in this study.

• Imaging Science in Dentistry
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• v.40 no.1
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• pp.9-14
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• 2010

Purpose : We evaluated the absorbed doses to the organs and calculated the effective doses when using the digital panoramic radiography. Materials and Methods : The absorbed dose averages in major organs of oral and maxillofacial region were measured using the Dental head phantom (CIRS Co., USA), $^nLi_2B_4O_7$ TLD chip and UD-716AGL dosimeter (Matsushita Electric Industrial Co., JPN) when performing indirect and direct digital panoramic radiography. Effective doses were calculated from correspond to ICRP 2007 recommendations for two panoramic radiography. Results : The absorbed dose average on indirect and direct digital panoramic radiography was highest in parotid glands as measured 1259.6 mGy and 680.7 mGy respectively. Absorbed dose average in another organs were high in order of esophagus, submandibular gland, tongue and thyroid gland on both types of digital panoramic radiography. The absorbed dose average was higher on indirect type than direct one (p<0.05). The effective dose was higher on indirect type than direct one as measured 13.28 mSv and 8.70 mSv respectively. Conclusion : The absorbed doses in salivary gland and oral mucosa were high. However, thyroid gland also demands the attention on radiography due to high tissue weighting factor in spite of the low absorbed dose.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.241-246
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• 2015

The interest of New Renewable Energy is increasing globally because of the increment of the uncertainty for the energy's supply and demand, and the increment of the frequency in weather anomaly and its damages. One of the New Renewable Energies, Hydrogen receives attention as the future energy that can deal with global environment regulation. Fuel Cell Electric Vehicle (FCEV) is an environment-friendly vehicle that uses Hydrogen as fuel. The electric power for FCEV is generated by chemical reaction with Oxygen from the air and Hydrogen. Hyundai Motor Company (HMC) has developed a proprietary fuel cell system since 2005. In 2012, HMC is the first car maker that mass-produces the ix35 FCEV to the worldwide such as North America, Europe, etc. In order to develop and improve the FCEV technology, data acquisition and analysis of the driving vehicle information is essential. Therefore, the monitoring system is developed, which is consist of datalogger, Automatic Vehicle Location (AVL) server and main server. Especially, WCDMA technology is integrated into the system which enables the data analysis without any restriction of time and region. The main function of the system is the analysis of the driving pattern and the component durability, and the safety monitoring. As a result, ix35 FCEV has successfully developed by using the developed monitoring system. The system is going to take an advantage of development in the future FCEV technology.

• Journal of the Korean earth science society
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• v.22 no.2
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• pp.112-119
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• 2001

The Yangsan fault in the southeastern Korea has been receiving increasing attention in its seismic activity. In this fault region, by using the extended coda-normalization method for 707 seismograms of local earthquakes, were obtained 0.009f$^{-1.05}$ and 0.004f$^{-0.70}$ for fitting values of Q$_p^{-1}$ and Q$_s^{-1}$, respectively. These results indicate that Q$_p^{-1}$ and Q$_s^{-1}$ in the southeastern Korea is the lowest level in the world although the exponent values agree well with those in the other areas. The low Q-1 is not related to the movement of the Yangsan fault but to the tectonically inactive status like a shield area.

• Tuberculosis and Respiratory Diseases
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• v.39 no.3
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• pp.271-277
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• 1992

Diffuse panbronchiollitis (DPB), a rare progressive disorder, has lately been receiving increasing attention. DPB is a disease of obscure etiology, characterized by chronic inflammation localized mainly in the region of respiratory bronchiole just distal to the terminal bronchioles. In 1983, Homma and coworkers reported 82 cases of a new clinicopathological entity, DPB, in Japan. Also DPB is a disease largely restricted geographically to Japan but the prevalence in other countries is extremely low. Histoloically, it is characterized by a suppurative bronchiolitis involving primarily the respiratory and terminal bronchioles with subsequent progression to bronchiectasis. The disease progresses rapidly and results in respiratory failure due to repeated respiratory infections. We experienced a cases of DPB accompanied with chronic maxillary sinusitis in both sinuses. Diagnosis of DPB was comfirmed by pathological results from thoracoscopic lung biopsy, typical radiological findings, clinical symptoms and pulmonary function test. After treatment with erythromycin for 6 months, the patient's condition and the typical micronodular densities on the chest radiography improved. A few case of DPB was reported in Korea. We report a case of DPB through thoracoscopic lung biopsy.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.825-832
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• 2010

Although a critical section reaches its flexural strength in reinforced concrete structures, the structure does not always fail because moment redistribution occurs during the formation of plastic hinges. Inelastic deformation in a plastic hinge region results in plastic rotation. A plastic hinge mainly depends on material characteristics. In this study, a plastic hinge length and plastic rotation are evaluated using the flexural curvature distribution which is derived from the material models given in Eurocode 2. The influence on plastic capacity the limit values of the material model used, that is, ultimate strain of concrete and steel and hardening ratio of steel(k), are investigated. As results, it is appeared that a large ultimate strain of concrete and steel is resulting in large plastic capactiy and also as a hardening ratio of steel increases, the plastic rotation increases significantly. Therefore, a careful attention would be paid to determine the limit values of material characteristics in the RC structures.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.506-511
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• 2004

Biometrics is getting more and more attention in recent years for security and other concerns. So far, only fingerprint recognition has seen limited success for on-line security check, since other biometrics verification and identification systems require more complicated and expensive acquisition interfaces and recognition processes. Hand-Geometry has been used for biometric verification and identification because of its acquisition convenience and good performance for verification and identification performance. Hence, it can be a good candidate for online checks. Therefore, this paper proposes a Hand-Geometry recognition system based on geometrical features of hand. From anatomical point of view, human hand can be characterized by its length, width, thickness, geometrical composition, shapes of the palm, and shape and geometry of the fingers. This paper proposes thirty relevant features for a Hand-Geometry recognition system. However, during experimentation, it was discovered that length measured from the tip of the finger was not a reliable feature. Hence, we propose a new technique based on Genetic Algorithm for extraction of the center of nail bottom, in order to use it for the length feature.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.3
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• pp.263-267
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• 2014

Super junction trench gate power MOSFETs have been receiving attention in terms of the trade-off between breakdown voltage and on-resistance. The vertical structure of super junction trench gate power MOSFETs allows the on-resistance to be reduced compared with conventional Trench Gate Power MOSFETs. The heat release of devices is also decreased with the reduction of on-resistance. In this paper, Lattice Temperature of two devices, Trench Gate Power MOSFET and Super junction trench gate power MOSFET, are compared in several temperature circumstance with the same Breakdown Voltage and Cell-pitch. The devices were designed by 100V Breakdown voltage and measured from 250K Lattice Temperature. We have tried to investigate how much temperature rise in the same condition. According as temperature gap between top of devices and bottom of devices, Super junction trench gate power MOSFET has a tendency to generate lower heat release than Trench Gate Power MOSFET. This means that Super junction trench gate power MOSFET is superior for wide-temperature range operation. When trench etching process is applied for making P-pillar region, trench angle factor is also important component. Depending on trench angle, characteristics of Super junction device are changed. In this paper, we focus temperature characteristic as changing trench angle factor. Consequently, Trench angle factor don't have a great effect on temperature change.

• Journal of the Korean GEO-environmental Society
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• v.4 no.3
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• pp.69-77
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• 2003

This study was carried out to evaluate the WASP5 model parameters and to analyze the sensitivity of parameters in Daechung Reservoir. The values predicted by the model and tendency were very similar to the observed data at Daejeon intake, so it is possible to predict water quality of the Daejeon intake region in the future. Results from the sensitivity analysis showed that Chlorophyll-a was sensitive to variations in saturated growth rate of phytoplankton, endogenous respiration rate of phytoplankton, extinction coefficient and temperature. T-N was sensitive to mineralization rate of dissolved organic nitrogen and temperature. T-P was affected by T-P load, temperature, extinction coefficient, mineralization rate of dissolved organic phosphorus and saturated growth rate of phytoplankton. BOD was influenced by deoxygenation rate and temperature, and DO was influenced by temperature. Adequate input data was applied and assessed through the model sensitivity analysis. So it is possible to distinguish the input data which need careful attention when it has application to model.

• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.123-132
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• 2011

Recently, DVC (Distributed Video Coding) is receiving a lot of attention as one of the low complexity video encoding techniques suitable for various applications with computation-limited and/or power-limited environment, and is being actively studied for improving the coding efficiency. This paper proposes a rate-distortion based selective block encoding scheme. First, the motion information is obtained in the process of generating side information at decoder and received through the feedback channel, and then, based on this information, the proposed method performs a selective block encoding based on rate-distortion optimization. Experimental results show that the performance of the proposed scheme reaches up to 2.2 dB PSNR gain over the existing scheme. Moreover, it is shown that the complexity can be reduced by encoding parts of region considering rate-distortion cost.