• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.185-187
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• 2000

Fault current is flowed into 154/23kV M. Tr when line-to-ground fault occurs in power system. NGR(Neutral Grounded Reactor) is set up in order to prevent M.Tr fault by limiting magnitude of fault currents. Here, disconnection of NGR causes voltage increase by L-C resonance and line-to-ground fault in an unearthed system results in voltage increase at healthy phases. So Over Voltage Ground Relay(OVGR) is used for tripping M.Tr. Also, buses at second phases of M.Trs are all connected with section circuit breakers closed for the purpose of parallel operation and load shedding. In case of speciality buses are comprised of power cable in part for GIS connection. When no-load charged cable or bus is open by a section CB, unbalanced voltage charged on the bus is induced. Also discrepant opening time for circuit breakers on different phases gives rise to unbalanced zero sequence voltage. It was observed that this zero sequence voltage detected in the 22.9kV P.T (Potential Transformer for bus) mal-operated 59GT and tripped M.Tr. The zero sequence voltage of which vanishing time is longer than relay operating time came out by EMTDC simulation. Also, it was shown that the voltage waves of actual test are similar to those of simulation. On the basis of above results, R-C circuit complement on the relay without any effect on a power system made operating time of the relay longer than vanishing time of distorted waves. Consequently, operating time of the relay was delayed and magnitude of distorted waves was decreased by increasing time constant of the relay.

• 말소리와 음성과학
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• 제7권4호
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• pp.139-145
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• 2015

The present study investigates the effects of syllable structure and prosodic prominence on the patterns of tonal alignment and scaling of the phrase-initial rise in Seoul Korean. Two syllable structures (Onset (/#CVC.../ as in minsa) vs. No-onset (/#VC.../ as in insa)) and two prominence conditions (Focus vs. Neutral) were considered. Results showed that the alignment of the L and the H tones in the phrase-initial rise was affected by syllable structure but not by prominence. The time of L was before the vowel onset of the first syllable in the Onset condition (i.e., within the onset consonant) and it was after the vowel onset in the No-onset condition. The difference was attributable to the fact that the initial L was anchored at a fixed distance from the phrase boundary, which was about 30ms after the onset of the syllable in both cases. The time of H was also consistently observed about 20ms after the second vowel onset (i.e., /a/ in minsa/insa). Moreover, the rise time (the duration from the L to the H tones) was longer as the local syllable duration became longer due to different syllable structure and prominence conditions. Taken together, the results provide a support for the segmental anchoring hypothesis, which claims that both the beginning and the end of F0 movement are consistently aligned with segmental 'anchor' points with relatively high stability (Ladd et al., 1999). Results also showed that the scaling of the early rise was slightly influenced by syllable structure but not by prominence. The differences between the results of the current study and a previous study (Cho, 2011) are further discussed.

• 전력전자학회논문지
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• 제8권3호
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• pp.274-284
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• 2003

대용량 전력변환기기인 멀티-레벨 컨버터는 전동기구동시스템 및 유연송전시스템 등에 널리 사용되고 있다. 이중 H-Bridge 컨버터는 캐스캐이드 형태를 사용하여 멀티-레벨로의 확장이 용이한 장점으로 인해 shunt형 기기로 점차 응용이 확대되고 있다. 정상 상태에서 대략 0.7∼0.8의 변조지수 범위에서 작동한다. 고변조지수에서는 부스트 벡터인 zero vector가 인가되지 않아도 DC-link 전압은 일정하게 유지된다. 이것은 3-레벨 컨버터의 여러 벡터 중 zero vector 이외에도 또 다른 boost vector가 존재한다는 것을 의미한다. 본 논문은 boost vector의 원리를 살펴보고 3레벨 컨버터에서 zero vector와 또 다른 boost vector와의 차이점을 고찰하였다. 또한 본 논문은 두 토폴로지의 충전 전류와 커패시터 전압을 해석하고 비교한다 이 전압과 전류는 스위칭 상태와 기준전압과 관련되어 있고 이것을 이용하여 각 커패시터의 충전전류와 전압리플에 대한 계산 방법을 제안하였고 다양한 DC-Link 전압제어 방법을 시뮬레이션을 통해 비교하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.5959-5963
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• 2012

Background: The term 'hardcore' has been applied to use of smoking tobacco and generally referred to as the inability or unwillingness of regular smokers to quit. The component constructs of hardcore except nicotine dependence are product neutral. With the use of 'time to first chew' as a measure of nicotine dependence, hardcore definition can be extended to characterize smokeless tobacco users. Hardcore users respond less to tobacco cessation interventions, and are prone to tobacco induced diseases including cancer. Thus identifying hardcore users would help in estimate the burden of high risk population for tobacco induced diseases. Smokeless tobacco use is predominant and accounts for more than 50% of oral cancer in India. Hence, hardcore chewing information could be used for planning of tobacco and cancer control interventions. The objective of this study was to assess the prevalence and associated factors of hardcore smokeless tobacco use in India. Materials and Methods: Global Adult Tobacco Survey (GATS)-India 2010 data were analyzed to quantify hardcore smokeless tobacco use in India with following five criteria: (1) current daily smokeless tobacco use; (2) no quit attempt in the past 12 months of survey or last quit attempt of less than 24 hours duration; (3) no intention to quit in next 12 months or not interested in quitting; (4) time to first use of smokeless tobacco product within 30 minutes of waking up; and (5) knowledge of smokeless tobacco hazards. Results: The number of hardcore smokeless tobacco users among adult Indians is estimated to be 5% (39.5 million). This group comprises 23.2% of daily smokeless tobacco users. The population prevalence varied from 1.4-9.1% across different national regions of India. Logistic regression modeling indicated age, education and employment status to be the major predictors of hardcore smokeless tobacco use in India. Conclusions: The presence of a huge number (39.5 million) of hardcore smokeless tobacco users is a challenge to tobacco control and cancer prevention in India. There is an unmet need for a universal tobacco cessation programme and intensification of anti-tobacco education in communities.

• Current Optics and Photonics
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• 제1권3호
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• pp.207-213
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• 2017

The Adaptive Front-lighting System (AFS) is a part of the active safety system, providing optimized vision to the driver during night time and other poor-sight conditions of the road by automatic adaptation of lighting to environmental and traffic conditions. Basically, an AFS provides four different modes of the passing beam as designated in an United Nations Economic Commission for Europe regulation (ECE324-R123): neutral state or country light (Class C), urban light (Class V), highway light (Class E), and adverse weather light (Class W). In this paper, we first present an optics design for an AFS system capable of producing the Class C/V/E/W patterns requiring only on/off modulation of multi-array LEDs with no need for any additional mechanical components. The AFS optics consists of two separated modules, cutoff and spread; the cutoff module lights a narrow central area with high luminous intensity, satisfying the cutoff regulation, and the spread module forms a wide spread beam of low luminous intensity. Each module consists of two major parts; the first converts a discretely positioned LED array into a full-filled area emitting light source plane, and the second projects the light source plane to a 25 m away target plane. With the combination of these two optics modules, the four beam patterns are formed by simple on/off modulation of multi-array LEDs. Then we report the development of a prototype that was demonstrated to provide the four beam patterns.

• Journal of Korean Neurosurgical Society
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• 제60권3호
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• pp.335-347
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• 2017

Intravenous recombinant tissue plasminogen activator had been the only approved treatment for acute ischemic stroke since its approval in 1995. However, the restrictive time window, numerous contraindications, and its low recanalization rate were all limitations of this modality. Under those circumstances, endovascular stroke therapy went through a great evolution during the past two decades of intravenous thrombolysis. The results of the 2013 randomized trials for endovascular stroke therapy were neutral, although they were limited by insufficient imaging screening at enrollment, early-generation devices with less efficacy, and treatment delays. Huge progress was made in 2015, as there were five randomized clinical trials which all demonstrated the safety and efficacy of endovascular stroke treatment. Despite differences in detail patient enrollment criteria, all 5 trials employed key factors for good functional recovery; (1) screening with non-invasive imaging to identify the proximal occlusion and exclude a large infarct core, (2) using highly effective modern thrombectomy devices mainly with stent retriever, and (3) establishment of a fast workflow to achieve effective reperfusion. The results of those trials indicate that modern thrombectomy devices can allow for faster and more effective reperfusion, which can lead to improved clinical outcomes compared to intravenous thrombolysis alone. These advances in mechanical thrombectomy are promising in the global fight against ischemic stroke-related disability and mortality. Two current mainstreams among such mechanical thrombectomy techniques, "stent retriever thrombectomy" and "direct clot aspiration", are the topic of this review. Stent retriever thrombectomy using Solitaire and Trevo retriever will be firstly discussed. And, the commonalities and the differences between two major clot aspiration thrombectomy techniques; a direct aspiration first pass technique (ADAPT) and forced arterial suction thrombectomy (FAST), will be additionally explained. Finally, details regarding the combination of direct clot aspiration and stent retriever thrombectomy, the switching strategy and the Solumbra technique, will be described.

• Asian-Australasian Journal of Animal Sciences
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• 제27권6호
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• pp.825-831
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• 2014

The aim of this study was to determine the nutritive value of some legume species in salt-affected soils of South-East Anatolian region using chemical composition and in vitro gas production kinetics. In this study, Lotus corniculatus, Trifolium alexandrinum, Medicago sativa were sown and tested in four different locations. A 3 by 4 factorial design with 3 legume species and 4 salt levels (non salty electrical conductivity (EC)<4 dS/m; low salt: 4 dS/m>EC<8 dS/m, medium saline: 8 dS/m>EC<16 dS/m and high salt: 16 dS/m>EC) was used in the study. Results indicated that salinity and plants had no significant effect on ash and ether extract. Dry matter (DM), acid detergent fiber, digestible dry matter, dry matter intake (DMI) were affected by plant, salinity and plant${\times}$salinity interaction. On the other hand neutral detergent fiber, relative feed value (RFV), and DMI were affected by salinity and plant${\times}$salinity interaction. Mineral contents were affected by plant species, salinity and salinity${\times}$plants interactions. In vitro gas production, their kinetics and estimated parameters such as were not affected by salinity whereas the gas production up to 48 h, organic matter digestibility, metabolizable energy (ME), and net energy lactation ($NE_L$) were affected by plant and plant${\times}$salt interaction. Generally RFVs of all species ranged from 120 to 210 and were quite satisfactory in salty conditions. Current results show that the feed value of Medicago sativa is higher compared to Lotus corniculatus and Trifolium alexandrinum.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.773-777
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• 2009

In recent years, the field of synthesizing voice has been developed rapidly, and the technologies such as reading aloud an email or sound guidance of a car navigation system are used in various scenes of our life. The sound quality is monotonous like reading news. It is preferable for a text such as a novel to be read by the voice that expresses emotions wealthily. Therefore, we have been trying to develop a system reading aloud novels automatically that are expressed clear emotions comparatively such as juvenile literature. At first it is necessary to identify emotions expressed in a sentence in texts in order to make a computer read texts with an emotionally expressive voice. A method on the basis of the meaning interpretation that utilized artificial intelligence technology for a method to specify emotions of texts is thought, but it is very difficult with the current technology. Therefore, we propose a method to determine only emotion every sentence in a novel by a simpler way. This method determines the emotion of a sentence according to an emotion that words such as a verb in a Japanese verb sentence, and an adjective and an adverb in a adjective sentence, have. The emotional characteristics that these words have are prepared beforehand as a emotional words dictionary by us. The emotions used here are seven types: "joy," "sorrow," "anger," "surprise," "terror," "aversion" or "neutral."

• Journal of Plant Biotechnology
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• 제36권4호
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• pp.320-326
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• 2009

The carbon dioxide concentration of the atmosphere is projected to increase by almost 50% over the first 50 years of this century. The major cause of this increase is continued combustion of fossil fuels. As a result, the significant changes in climate that have already occurred will be amplified, in particular a global temperature increase. Renewable energy production has a central role to play in abating net $CO_2$ emissions to a level that will arrest the development of global warming. Especially, biomass crops are becoming increasingly important as concerns grow about climate change and the need to replace carbon dioxideproducing fossil fuels with carbon-neutral renewable sources of energy. To succeed in this role, biomass crop has to grow rapidly and yield a reliable, regular harvest. A prime candidate is Miscanthus, or Asian elephant grass, a perennial species that produces over 3 metres of bamboo-like stems in a year. Miscanthus species are typically diploid or tetraploid. Hybrids between species with different ploidy levels result in the highly productive triploid hybrids, M. ${\times}$ giganteus. Here we will detail the Miscanthus characteristics desired of a biomass fuel crop.

• 한국물환경학회지
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• 제33권3호
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• pp.348-358
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• 2017

The process of evaluating and selecting the best available techniques presents various characteristics for each country. In the case of EU, BAT is selected through TWG meeting after first screening, mass and energy balance, impact assessment and decision support process. Korea has proposed four principles to select BAT that can be carbon neutral for each environmental infrastructure in order to reduce greenhouse gas emissions. In order to evaluate and select the best available technique, it is necessary to differentiate the method according to whether it is a technique generally applied at the current workplace, whether it is a single technique or a combination technique, and whether it is a technology technique or management technique. In the case of a single technique, it should be evaluated whether it is a technique applied in the workplace, excessive cost, superior environmental technique over BAT, and secondary environmental pollution. In the case of multiple techniques, it is necessary to examine whether the emission standards are met and whether the pollutants can be treated at the same level as BAT. In the case of BAT candidates for management techniques, whether or not they contribute directly or indirectly to lowering the emission level of pollutants can be an important evaluation item. In the case of environmental techniques that are not generally applied in the workplace, it is recommended that the following 8 steps be carried out, including those prescribed by law. In the first stage, the list of performance evaluation factors is listed. In the second stage, the level of disposal of pollutants and the level of satisfaction with standards are listed. In the third stage, the environmental evaluation elements are listed. In the fourth stage, Is to list the economic evaluation elements, step 6 is to list the pollution and accident prevention evaluation factors, step 7 is the quantitative evaluation of the technical working group, and step 8 is BAT confirmation through deliberation of the central environmental policy committee.