• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.15-25
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• 2015

The growth of impermeable layers in the city center due to today's urban development is emerging as a major cause of urban heat island effects as well as recurring inland flood damages. In order to cope with such disasters caused by climatic changes, an artificial ground afforestation system is suggested as a fundamental solution that addresses both water environment and heat environment. For the afforestation system to replace the current disaster prevention facilities, quantitative performance verification through related numerical analysis models and actual survey monitoring is necessary. Therefore, this study seeks to propose the performance predication method for the heat environment of the afforestation system by looking into correlations between measurements by physical vegetation indicators such as LAI and FVC and forecasts from FASST, a vegetation canopy model used by US Corps of Engineers.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.564-570
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• 1997

The most important factor for the desalination system is the fresh water production cost dependent upon the possible energy source which should be obtained easily and with low price. Recently in Korea the demand of LNG, as a cheap and clean energy which does not cause an environmental problem, has sharply been increased. In general, LNG is storaged in a tank as a liquid state below -162 'C. When it is serviced, however, the LNG absorbs energy from a heating source and transforms to the gaseous state with high pressure. During this process a huge amount of cold energy accumulated in LNG is wasted. This waste cold energy can be utilized for producing fresh water from sea water using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique, a qualitative and quantitative data regarding the freezing behavior of sea water is needed in advance. The goal of this study, therefore, are to reveal the freezing mechanism of sea water, to measure the freezing rate, and to investigate the freezing heat-transfer characteristics. The experimental results help to provide a general understanding of the sea water freezing behavior in a Rectangular vessel cooled from below.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.843-859
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• 2018

Cybersecurity has emerged as a serious problem in Korea and there have been relevant movements to improve domestic cybersecurity policy and system. However, discussions have yet to result in actual progress and the legislation for improvement of cybersecurity policy and system have been stagnant until now. As evidenced by the introduction of primary government legislation bill for national cybersecurity in 2017, the preparations for improvements to the policy and system are still in progress. However, we cannot be positive about the possibility of implementing these improvements during the process. Recognition of the importance of cybersecutiry has gradually risen and is more prevalent than in years past, however, in-depth discussions are not being made. In principle, misunderstandings about cybersecurity itself and insufficient understandings of the relevant legislation seem to cause such problems. Therefore, it is necessary to review key issues related to the improvement of cybersecurity policy and system and reconsider tasks for the future. Such issues include the relationship between cybersecurity and fundamental rights, establishing responsibility and capability of each of entities for cybersecurity, and the role of the military in cybersecurity. This type of in-depth discussion will be helpful for finding ways to improve upon cybersecurity policy and system. Moreover, this study aims to key issues with questionnaire survey and political and normative inquiry.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.89-98
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• 1997

Compression waves propagating in a high speed railway tunnel impose large pressure fluctuations on the train body or tunnel structures. The pressure fluctuations can cause ear discomfort for the passengers and increase the aerodynamic resistance of trains. As a fundamental research to resolve the pressure wave phenomenon in the tunnel, a steady theory of Chester-Chisnell- Whitham was applied to a simple shock tube with a sudden cross-sectional area reduction to model trains inside the tunnel. The results of the present theoretical analysis were compared with the experiments of the shock tube. The results show that the reflected compression wave from the model becomes stronger as the strength of incident compression wave and the blockage ratio increase. However, the compression wave passing through the model is not strongly dependent on the blockage ratio. The theoretical results are in good agreement with the experiments.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.2
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• pp.140-144
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• 2001

Backgrounds & Objectives : Prolonged hearing loss was considered as one of the factors which have the potential to cause vocal changes. However, the analysis of quality of phonation in hearing loss patients has not been achieved enough. The purpose of the study was to evaluate the difference in objective acoustic parameters between long-term hearing impaired patients and normal control group. Material & Methods : The material of this investigation comprised a group of 20 patients (M : F=10 : 10) with moderate or profound hearing loss(over 50dB). The duration of all hearing loss was over 1 year. All of them underwent the acoustic examinations comprising electroglottography, multidimensional voice program and formant analysis during phonation of the bowels /a/ with free confortable tone and /i/ with voluntary high tone. The results of the acoustic examinations were compared with those of a control group, composed of 20 sex- and age-matched normal hearing subjects. Results : In the male hearing loss subjects, the significant increase was detected in pitch and shimmer during phonation of /a/ and in pitch during phonation of /i/. In addition, this group was characterized by decreased fundamental frequency during phonation of /i/. In female, there was no difference between hearing loss group and normal control group except a decreased formant 1 frequency. Conclusion : Long-term moderate and profound sensorineural hearing loss could affect the objective voice parameters.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.27 no.1
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• pp.5-10
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• 2016

Variable systemic diseases affect larynx and vocal fold and result in voice change. Asthma and chronic obstructive pulmonary disease make increase of intra-abdomimal pressure followed by reflux of gastric acid, which stimulate vagal-bronchopulomary reflex aggravating cough and respiratory disturbance. Fungal laryngitis in the general population is extremely rare, but can occur in immunocompromised AIDS patients. Although, initially, empirical antifungal therapy for candidiasis is often given without biopsy, diagnostic direct laryngoscopy and biopsy is imperative if a substantial clinical response is not rapidly achieved. In the highly active anti-retroviral therapy era, HIV-positive patients are living longer and are at higher risk for developing non-AIDS-defining malignancies. The incidence of head and neck cancer (HNC) which is related with human papilloma virus infection has increased. The survival is significantly lower among the AIDS-HNC patients with CD4 counts ${\leq}200cells/{\mu}L$. Rheumatoid arthritis (RA) cause voice disturbance by developing cricoarytenoid joints fixation or nodule on vocal fold. Post-menopausal voice disorder (PMVD) is caused by decreased secretion of estrogen-progesterone resulting in decrease of fundamental frequency (F0). Hormonal replacement therapy is helpful to reduce F0 decrease. RA and PMVD result in slight voice change, but it could crucial in professional voice user.

• Progress in Superconductivity
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• v.11 no.1
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• pp.13-18
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• 2009

Partial discharge measurements in cryogenic dielectric materials of HTS transformer are very important because partial discharge was regarded as primary source for ageing and breakdown of cryogenic materials. But, partial discharge measurement techniques and its effects in low temperature high voltage environments were not suggested and there exist only a few reports on this research fields. Therefore, in order to implement reliable HTS transformers, partial discharge diagnosis techniques for cryogenic materials of HTS transformers were investigated using partial discharge (PD) pattern analysis methods. In this works, four different types of artificial defects including turn to turn insulation, free moving particle, void and protrusion, have been fabricated since it was commonly regarded that they might cause the sudden service failures of the power apparatus. For this purpose, these defects are installed into the dielectric materials in liquid nitrogen and experimental investigations have been carried out for the diagnosis of HTS transformer. And various PD patterns caused by the amount of quench of superconductors were analyzed. Throughout this works, the different PD patterns in cryogenic dielectric materials in liquid nitrogen, and PD measuring technique could be the fundamental steps to establish diagnosis technologies of HTS transformer for power applications.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.611-614
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• 1991

In variable speed driving system of three phase induction motor controlled by an inverter, because of the switching of semiconductor devices in inverter, an appreciable amount of harmonic components of voltage waveform can cause the motor to generate losses, torque ripple, acoustic noise and oscillation of semiconductor devices. In this paper a new PAM type PWM inverter using IGBT is described. The output waveforms in the proposed PAM type PWM inverter are investigated both theoretiically and experimentally. The line-voltage waveform is composed of fundamental component and the sidebands of carrier frequency. The lower order harmonics are not included in the output wave form. As each inverter arm does not operate during two-thirds period, the heats, generated in the devices are reduced. That is, the size of the inverter system can he minimized because of the reduction in the heat dissipating equipment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.6
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• pp.1157-1162
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• 2001

This paper deals with inspect algorithm using visual system. One of the major problems that arise during polymer production is the estimation of the noise of the color product.(bad pallets) An erroneous output can cause a lot of losses (production and financial losses). Therefore new methods for real-time inspection of the noise are demanded. For this reason, we have presented a development of vision system algorithm for the defect inspection of PE color pallets. First of all, in order to detect the edge of object, the differential filter is used. And we apply to the labelling algorithm for feature extraction. This algorithm is designed for the defect inspection of pallets. The labelling algorithm permits to separate all of the connected components appearing on the pallets. Labelling the connected regions of a image is a fundamental computation in image analysis and machine vision, with a large number of application. Also, we suggested vision processing program in window environment. Simulations and experimental results demonstrate the performance of the proposal algorithm.

• The Journal of Internal Korean Medicine
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• v.21 no.5
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• pp.739-745
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• 2000

xWe studied about the causes of hypertension in the occidental and oriental medical records and the results are as follows. 1. The causes of hypertension in oriental medicine can be divided into wind, fire, phlegm and deficiency of Qi in our body, and broadly into three categories as emotions in excess, improper diet and damages of endogenous etiological factors. 2. Hypertension is the disease of undermining of fundamental aspects while prevailing incidental aspects and liver, heart and kidneys are the organs mainly related to hypertension. 3. The main pathological factors of hypertension are as follows; the disorder of Yin and Yang makes the situation of the deficiency of the vital essence of kidneys and the exuberance of the vital essence of liver and they are the fundamentals to be taken hypertension and finally make the state of the deficiency of both Yin and Yang. 4. In the point of occidental medical view, the essential hypertension is a disease of unknown etiology and we think it occurs not on the only one factor but on the various factors and secondary hypertension occurs from the diseases of the substances and the vessels of kidneys.