• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.212-215
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• 2019

지난 4월4일 고성 산불로 사망자 2명과 부상자 1명, 가옥 500여 채, 삼림 1757ha가 불에 탔다. 강원 산불에 이어 영덕지진 등에서 늑장대응을 보여준 재난방송시스템에는 많은 국민들에게 실망감을 안겨주었다. 재난방송 주관방송사인 KBS는 물론, MBC, SBS의 경우도 재난방송시스템에 관련 된 측면에서 본다면 아직 이웃나라 인 일본에 비해서는 매우 열악한 형편이다. 그럼에도 불구하고 점점 대형화, 다발화 하는 재난발생에 대응하기 위해서는 국가적인 차원에서도 특단의 조치가 필요하다. 미국의 경우는 차세대 재난정보 전달체계인 IPAWS(Integrated Public Alert and Warning System)를 개발해 지상파뿐만 아니라, 케이블TV, SNS 등 다양한 매체를 통해 재난정보를 신속하게 전달하고 있다. 일본도 이와 유사한 재난경보전달시스템인 J-Alert를 개발해 2020년까지는 '재난 약자 제로(Zero)시대'를 목표로 구현하고 있다. 우리나라는 지난 아현동 KT 화재사건에서도 경험했듯이 통신이 먹통이 되는 통신블랙아웃도 경험했다. 따라서 대형재난발생 시는 신속한 재난경보전달시스템이 재난피해를 줄일 수 있는 가장 중요한 생명줄이 될 수 있다. 미국이나 일본의 경우는 재난방송전달시스템을 관련법령으로 제도화 하고 있다. 특히, 일본에는 재난에 관한 모법이라고 할 수 있는 (1)"재해대책기본법"이 있는데, 이는 재해로부터 국토, 국민의 생명과 재산을 보호하기 위한 기본법으로 규정되어 있다. 그 밖에도 (2)방송법 (3)대규모지진대책특별 조치법 (4)국민보호법 (5)소방조직법 (6)수해방지법 등으로 규정하고 있다. 과거 일본도 우리나라와 같이 대형 산불이 잦았으나 요즘은 소형 산불만 발생하는 추세다. 이는 NHK가 보유한 700여 대의 로봇카메라와 전 국토를 샅샅이 감시하는 CCTV 덕택이다. 또한, NHK 보도국의 '기상 재해센터'는 재난에 대비해 40여 명의 전문 인력이 24시간 대응체제를 갖추고 있다. 나아가 NHK는 전국 12개의 거점지역에 헬리콥터 15대를 배치하여 신속하게 취재하고 있다. 이 뿐만 아니라, 46개의 지역방송국을 7개의 거점방송국으로 분할하여, 거점방송국마다 40여명의 카메라맨을 상주시켜 언제든지 재난을 취재할 수 있도록 하고 있다. 세계 각국에서 사용하고 있는 방송 주파수는 공공재(公共材)다. 국제전기통신연합(ITU : International Telecommunication Union)으로부터 주파수를 할당받아 사용하고 있기 때문에 주파수에 관한 사용 권한은 각국의 국민 모두에게 있다. 그러나 효과적인 주파수 활용을 전제로 정부가 일정한 자격을 갖춘 방송사업자에게 일시적으로 주파수 사용권을 위임하고 있다. 따라서 일본 정부도 국가적인 위기나 대형 재난발생으로 국민들의 생명과 재산이 위협받고 있을 때에는 공공재인 주파수를 즉시 재난방송으로 사용할 수 있도록 <재해대책기본법 제6조>와 방송법 제108조에 규정하고 있다.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.49-55
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• 2019

This study sought to investigate whether mean speaking fundamental frequency (SFF) can be predicted by parameters of voice and speech range profile (VRP and SRP) in Korean normal adults. Moreover, it explored whether gender differences exist in the absolute differences between the SFF and estimated SFF (ESFF) predicted by the VRP and SRP. A total of 85 native Korean speakers with normal voice participated in the study. Each participant was asked to perform the VRP task using the vowel /a/ and the SRP task using the first sentence of a Korean standard passage "Ga-eul". In addition, the SFF was measured with electroglottography during a passage reading task. Predictive factors of the SFF were explored and the absolute difference between the SFF and the ESFF (DSFF) was compared between gender groups. Results indicated that predictive factors were age, gender, minimum pitch and pitch range for the VRP (adjusted $R^2=.931$), and pitch range (in semi-tones) and maximum pitch for the SRP (adjusted $R^2=.963$), respectively. The SFF and ESFF predicted by the VRP and SRP showed a strong positive correlation. The DSFF of the VRP and SRP, as well as their sum did not differ by gender. In conclusion, the SFF during a passage reading task could be successfully predicted by the parameters of the VRP and SRP tasks. In further studies, clinical implications need to be explored in patients who may exhibit deviations in SFF.

• Journal of Korea Port Economic Association
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• v.35 no.2
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• pp.61-76
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• 2019

The purpose of this study is to use the EGARCH model and Granger causality test to analyze how the change in the BDI affects the Korean stock price volatility. The main analysis results are summarized as follows. First, according to the results of the mean equation, the change in the BDI is significant in large-cap stocks, as well as in the manufacturing, service, and chemistry indexes, but not in others. This implies that the Korean stock market does not respond appropriately to the maritime market situation; further, the increase in demand for raw materials has not led to a real economic recovery. Second, in the result of the variance equation, the coefficient on the change in the BDI is negative(-), and the change in the BDI is significant for all size indexes. Particularly, the change in the BDI has a greater impact on the volatility of small-cap stocks than that of large-cap stocks. The results of the analysis of the sector indexes were statistically significant for the service, financial, construction, and electric and electronics industries, but not for the manufacturing and chemical industries. In particular, the changes in the BDI have the greatest impact on the construction industry. Third, according to the Granger causality test results, the change in the BDI leads the financial industry and construction industry. There is, however, no relationship between the BDI and the other indexes. This shows that change in the shipping freight index can be used to predict the volatility in the Korean stock market. This can help investors and policymakers make better decisions.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.449-455
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• 2019

This paper proposes a flyback diode of bridgeless PFC converter as SiC SBD (Schottky Barrier Diode) to achieve high efficiency. In addition, through the explanation of the operation principle of the bridgeless PFC converter, the conduction section of the freewheel diode is shown in the bridgeless PFC converter to verify the contribution of system loss due to the loss of the freewheel diode. The advantages of the SiC SBD device's physical properties and the reverse recovery characteristics are explained, and the efficiency is measured by measuring the turn-on and turn-off losses. The loss was calculated. The simulation results were calculated in consideration of device characteristics and verified through the waveform analysis and comparison of the actual system. In order to consider the device characteristics, the simulation was conducted using the thermal module of PSIM. As a result of the prototype test, the turn-on loss was 0.608W and the turn-off loss was 21.62W, resulting in the total switching loss of 22.228W. The comparison of the two results proved the validity of the experimental method. In addition, a high efficiency of 94.58% is achieved.

• Journal of the Korea Convergence Society
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• v.10 no.8
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• pp.181-193
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• 2019

The regional economy growth of Jeju has seen higher than national growth since 2011 by the establishment of Jeju Special Self-Governing Province and the increase of incoming population, but its economic growth has slowed after 2016. This study conducted the dynamic shift-share analysis using the production and employees of each industry from 2010 to 2016, targeting Jeju with many factors of regional economic change. In the results of empirical analysis, the regional economy of Jeju was not the industrial structure depending on the national growth, but the industrial structure by the competitiveness and industrial structure of Jeju region. The industries having positive(+) effects of industrial mix effect and competitive effect on the production and the number of employees were the electricity/gas/heavy equipments & waterworks, construction, accommodation & restaurants, and service industry. These industries have positive effects on the regional industry of Jeju. The above-mentioned industries are not only more likely to grow than other regions, but also to drive the local economy of Jeju. In order for these industries to continuously contribute to the regional economy of Jeju, it would be necessary to have the policy/institutional support in the long-term perspective.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.387-411
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• 2007

The analysis of ancient DNA (aDNA) has become increasingly considerable anthropological, archaeological, biological and public interest. Although this approach is complicated by the natural damage and exogenous contamination of a DNA, archaeologists and biologists have attempted to understand issues such as human evolutionary history, migration and social organization, funeral custom and disease, and even evolutionary phylogeny of extinct animals. Polymerase chain reaction(PCR) is powerful technique that analyzes DNA sequences from a little extract of an ancient specimen. However, deamination and fragmentation are common molecular damages of aDNA and cause enzymatic inhibition in PCR for DNA amplification. Besides, the deamination of a cytosine residue yielded an uracil residue in the ancient template, and results in the misincorporation of an adenine residue in PCR. This promotes a consistent substitution (cytosine thymine, guanine adenine) to original nucleotide sequences. Contamination with exogenous DNA is a major problem in aDNA analysis, and causes oversight as erroneous conclusion. This report represents serious problems that DNA modification and contamination are the main issues in result validation of aDNA analysis. Now, we introduce several criterions suggested to authenticate reliance of aDNA analysis by many researchers in this field.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.136-142
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• 2019

Water spider(Argyroneta aquatica) inhabits only a small size wetland in Eundae-ri, Yeoncheon-gun. In this study to investigate environmental factors influencing on population of A. aquatica, we analyzed the relationship between density of A. aquatica and various physicochemical and biological factors. Density of A. aquatica increased with small habitat area and high $NH_4$ and electric conductivity. The relationship between density of A. aquatica and prey or predator was low but the water spider decreased with density of Pomacea canaliculata. And density of A. aquatica was not related to the coverage of emergent plant. However density of A. aquatica decreased as the increase of floating plant and increased as the increase of submerged plant. These results indicated that aquatic plants are important in the habitat environment of A. aquatica. Therefore we suggest necessity of management strategies for the invasive species, P. canaliculata which is a notorious predator of aquatic plants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.497-502
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• 2019

Metal oxide nanostructures are promising materials for advanced applications, such as high sensitive gas sensors, and high capacitance lithium-ion batteries. In this study, tin oxide (SnO) nanostructures were grown on a Si wafer substrate using a two-zone horizontal furnace system for a various substrate temperatures. The raw material of tin dioxide ($SnO_2$) powder was vaporized at $1070^{\circ}C$ in an alumina crucible. High purity Ar gas, as a carrier gas, was flown with a flow rate of 1000 standard cubic centimeters per minute. The SnO nanostructures were grown on a Si substrate at $350{\sim}450^{\circ}C$ under 545 Pa for 30 minutes. The surface morphology of the as-grown SnO nanostructures on Si substrate was characterized by field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). Raman spectroscopy was used to confirm the phase of the as-grown SnO nanostructures. As the results, the as-grown tin oxide nanostructures exhibited a pure tin monoxide phase. As the substrate temperature was increased from $350^{\circ}C$ to $424^{\circ}C$, the thickness and grain size of the SnO nanostructures were increased. The SnO nanostructures grown at $450^{\circ}C$ exhibited complex polycrystalline structures, whereas the SnO nanostructures grown at $350^{\circ}C$ to $424^{\circ}C$ exhibited simple grain structures parallel to the substrate.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.116-123
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• 2019

Thermal batteries are also called molten-salt batteries as the electrolyte is mainly composed of molten salt. The molten-salt electrolyte is a solid that does not conduct electricity at room temperature, but when it is melted by a pyrotechnic heat source, it becomes an excellent ionic conductor. Thermal batteries are a kind of pyrotechnic battery because they operate only when the solid electrolyte is melted by the heat energy provided by pyrotechnic materials. Pyrotechnic components used in a thermal battery include heat sources, fuse strips, and an igniter. The reliability of these pyrotechnic components critically affects the reliability and performance of the battery that must supply electricity stably to guided munitions even under extreme environmental conditions. Different igniter types offer different advantages: notch-type igniters offer improved ignition probability, whereas film-type igniters offer improved safety. The addition of metal oxides to the heat paper could improve the burn rate, and the ignition reliability could be greatly improved by using it with a flame igniter at the same time. Using a two-step reduction process, high-purity Fe particles in coral form can be safely obtained.

• Journal of Adhesion and Interface
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• v.20 no.1
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• pp.9-14
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• 2019

The change of three different reagents for electrical conductive paint using aircraft coating with elapsing time of exposure to different condition was investigated. Three different reagents were poured into the vial bottles, stored in air condition and room temperature and observed with elapsing days. In addition, adhesion property of paint was tried using cross cut tape test after storage of $N_2$ atmosphere. The weight of each different reagent was measured along with elapsing time. To confirm the change of chemical component with exposure of air atmosphere, FT-IR was performed. The weight of part A and Part B decreased slightly whereas the weight of part C decreased rapidly and the precipitation was remained. The part B was cured after exposure of $N_2$ atmosphere and the 2250 cm-1 from FT-IR peak decreased slowly at the same time. It was considered that the water contained in air accelerated the reaction of -NCO functional groups and it caused the curing whereas $N_2$ atmosphere not contained water and it resulted in the retardancy of curing.