• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.6-11
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• 2009

최근 경제발전과 산업화를 통한 도시화로 인하여 많은 자연하천이 심하게 훼손되고 있으며 도시하천의 경우 치수의 효율성을 강조한 하천정비를 실시함으로써 하천의 외경은 깨끗하게 바꾸어 놓았지만 그로 인한 하천생태계의 파괴가 문제점으로 대두되고 있다. 이에 따라 생태적으로 훼손된 하천의 생태복원이 최근 들어 활발히 추진되고 있으며 하천변의 식물 및 어류 등 다양한 생물에 대한 서식공간의 마련이 주요 이슈로 연구되어지고 있다. 본 연구에서는 2차원 수리서식모형인 River2D를 대표적인 도시하천인 대전천에 적용하여 대전천의 멸종위기에 처해 있는 감돌고기 및 우점종인 피라미를 대상으로 대상 어류의 서식처 제공을 위한 수리학적 분석을 시도하였다. 또한 자연친화적 서식처 개선 공법으로서 거석을 하도 내에 배치함에 따른 가중가용면적의 변화를 비교 검토하였으며 감돌고기를 위한 최적의 서식처 개선 방안을 제시하였다. 현재 상태의 대상하천에 대한 어류서식처를 모의분석한 결과, 현재 직선화되고 단조로운 하천흐름은 피라미의 서식환경에 적합한 것으로 나타났으며 가중가용면적의 경우 감돌기에 비하여 피라미가 약 20배정도 크게 나타났다. 어류서식처 조성공법의 WUA를 산정한 결과 V형 여울공법이 감돌고기의 서식환경을 360%, 징검다리 거석공법이 60%, 외톨이 거석공법이 8%이상 상승시키는 것으로 나타났다. 반면, 거석(Boulder)을 적절히 배치하여 서식처를 개선하는 방법의 경우에도 거석간 간격을 3.5m로 하여 배치하는 경우가 가장 효율적인 것으로 나타났으며 거석을 이용한 여러 가지의 배치형태 중에서 수류를 중앙으로 집중시켰을 때 감돌고기의 서식처가 급격하게 상승하는 것으로 나타났다. 따라서 하도 내 거석의 배치시 하도 및 대상어종의 특성을 고려하여 적절한 배치간격 및 배치방법을 연구하여 시행되어야 할 것이다.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.89-99
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• 2010

Newcastle disease (ND), caused by Newcastle disease virus (NDV), has caused periodic epidemics in Korea at an interval of 3 to 5 years until the early 2000s. At least five distinct genotypes of NDV have been responsible for epizootic episodes in Korea; genotype III virus (before the 1970s), genotype V (the mid-1980s), genotype VI (the late 1980s to early 1990s), genotype VIIa (the mid-1990s), and genotype VIId viruses (the late 1990s to present). Recent epidemic strains of NDV (VIId viruses) shared geographical features with neighboring countries such as China and Japan. These VIId viruses as well as genotypes III and V viruses were viscerotropic and highly virulent for chickens. Antigenic variation occurred between VIId field viruses and LaSota vaccine strain, as found in other epidemic strains in past in Korea. Nevertheless the commercial vaccine was considered to effectively protect vaccinated birds from mortality against VIId viruses as well as other viruses belonging to genotypes III and V.

• Journal of the Korean Chemical Society
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• v.21 no.5
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• pp.379-383
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• 1977

Since the organophilic bentonite disperses well in polymer matrix, a composite material of polymer and bentonite was studied for its mechanical properties. To increase the degree of dispersion and the bond in forces to the polymer matrix, bentonite, encapsulated by imidazoline, was used as a filler. Polyethylene powder of particle size of 100 mesh was used, and organophilic bentonite, so-called bentone, whose particle size was 250 mesh was also used in this experiment. V-type mixer was used for mixing and Banbury mixer was used for melt-blending. The sample specimen were made by heating the mixture in the plate press, and the specimen were formed as a sheet, exactly the same as the mold on the plate. Tensile strength, bending strength and compressive strength were studied specially. Tensile strength, elongation rate, bending strength and bending rate at constant pressure were decreased as the filler content increased. Compressive strength was increased as the filler content increased.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.71-83
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• 1994

This paper deals with the improvement of the synthesized speech quality and naturality in the Korean TTS(Text-to-Speech) system. We had extracted the parameters(table2) such as its amplitude, duration and pitch period in a syllable through the analysis of speech waveforms(table1) in the time domain and synthesized syllables using them. To the frequencies of the Korean pronunciation large vocabulary dictionary we had synthesized speeches selected 229 syllables such as V types are 19, CV types are 80. VC types are 30 and CVC types are 100. According to the 4 Korean syllable types from the data format dictionary(table3) we had tested each 15 syllables with the objective MOS(Mean Opinion Score) evaluation method about the 4 items i.e., intelligibility, clearness, loudness, and naturality after selecting random group without the knowledge of them. As the results of experiments the qualities of them are very clear and we can control the prosodic elements such as durations, accents and pitch periods (fig9, 10, 11, 12).

• Bulletin of the Society of Naval Architects of Korea
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• v.1 no.1
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• pp.9-16
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• 1964

As a pre-study for researches on powering characteristics of straight-framed V-bottom hull forms for usual commercial vessels, practicability of such a hull is investigated from viewpoints of over-all ship economy. For this purpose, a trawler hull of straight-elements with double chines, SV(T)-1, similar to Prof. Nevitt's W-8 in size and hull form coefficients was designed and tested at the SNU Ship Model Towing Tank for resistance measurements. The result is given in Fig.3 together with those of W-8 and other equivalent hulls of double curvature, such as FAO 135a-173, Doust and Takgi. The curves of the latters are reproduction of Prof. Nevitt's analysis, and given for comparison purpose. With in speed range of $9.0{\sim}10.5$ konts the resistance coefficients of SV(T)-1 are $18{\sim}25%$ higher than those of W-8, and $5{\sim}20%$ and $12{\sim}14%$ higher than those of FAO 135a-173 and Doust respectively. SV(T)-1, however, is slightly superior in resistance characteristics than Takagi's equivalent hull within the speed range. On the other hand, an equation for reduction rates of hull construction cost required to compensate for propulsion power increase in straight-elements hulls was derived from the definition of the economic efficiency of commercial vessels. The solution of the equation is given in Fig.4 graphically, from which it is known that $10{\sim}20%$ increase in propulsion power can be compensated by $8{\sim}16%$ reduction in hull construction cost. Considering simplicity and less equipments required in construction of straight -elements hulls, the author does argue for attainability of the above reduction rates in hull construction cost. Consequently, it is concluded that there is clear feasibility to adopt straight-elements hulls for usual commercial vessels of medium and small-size. And a further research will be done to obtain reliable data for chine shapes having good flowliness with the flow around ships depending on ship's size and speed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.5
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• pp.429-437
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• 2008

In this study the progressive collapse potential of braced frames were investigated using the nonlinear static and dynamic analyses. All of nine different brace types were considered along with a special moment-resisting frame for comparison. According to the pushdown analysis results, most braced frames designed per current design codes satisfied the design guidelines for progressive collapse initiated by loss of a first story mid-column; however most model structures showed brittle failure mode. This was caused by buckling of columns after compressive braces buckled. Among the braced frames considered, the inverted- V type braced frames showed superior ductile behavior during progressive collapse. The nonlinear dynamic analysis results showed that all the braced frame model structures remained in stable condition after sudden removal of a column, and their deflections were less than that of the moment-resisting frame.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.97-103
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• 2004

Most of the columns in centrally braced steel frame buildings are usually designed as the gravity columns to reduce connection cost. For a rational seismic performance evaluation of centrally braced steel frame buildings, it is important to properly incorporate in the analysis  the P-${\Delta}$ effects arising from the gravity columns. An effective scheme for the P-${\Delta}$ effects modeling due to the gravity columns was illustrated based on the concept of fictitious leaning column. Seismic performance evaluation of inverted V braced steel frames with or without P-${\Delta}$ effects modeling was conducted by following the FEMA 273 NSP (Nonlinear Static Procedure). The problem in estimating dynamic P-${\Delta}$ modification factor (C3) in FEMA 273 was discussed. The results of this study indicated that the P-${\Delta}$ effects should be included in the seismic performance evaluation of centrally braced steel frames. This study also showed that the inverted V braced frames, retrofitted by applying the tie bars to redistribute the inelastic demand over the height of the building, exhibit significantly improved seismic performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6282-6288
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• 2014

$CO_2$ welding is used widely in the field. On the other hand, welding defects occur when welders cannot adjust the current and voltage needed for welding and have to stop working to adjust the current and voltage, causing sudden cooling down of the welding structure inside a vehicle or tank where the control panel is invisible or when work site is far. This study used three types of existing $CO_2$ welders. This also applied SS400 rolled steel for welding structural purposes for remote control torch welding, perform a welding test through v-groove butt welding with a remote control torch and existing $CO_2$ welding torch, conducted visual inspection on the appearance of a welded top bead. In addition, the appearance quality of the welding part was monitored mainly through penetrant testing and a bending test to evaluate the welding defect reduction and the effect on the performance and compatibility by replacing the existing welder.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.942-949
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• 2005

To improve the textural properties and stabilize the structure and gel matrix of non-waxy rice starch gels, non-waxy rice starch/gum mixture gels were prepared from various food gums, gum arabic, guar, algin, deacyl gellan, xanthan and gellan gums. The morphological and textural properties and freeze-thaw stability of their gels were compared. Rice starch/gum mixture gels with various gums formed a more homogeneous gel matrix with smaller particle size than rice starch gel without Em, but the trends differed depending on the gum types. The textural properties of rice starch/gum mixture gels were changed with the gum types. The shape of the rice starch/gum mixture gel matrix was desirable when mixed with gellan and algin. The textural properties of gels hardened in the rice starch/algin mixture gel and softened in the rice starch/algin mixture gel. The rice starch gels showed V-type crystallinity by x-ray diffractometer, but the peak at $2\theta$ = $20^{o}$ was decreased with increasing gum addition. The freeze-thaw stability increased with increasing gum addition. Gellan and algin were especially effective.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.234-240
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• 2022

Floating-Harbor syndrome (FHS) is a rare genetic disorder. This report introduced in a patient with FHS. Distinctive facial characteristics, severe skeletal class 3 malocclusion with underdeveloped maxilla and protruded mandible, congenital missing teeth, microdontia and ectopic positions of maxillary teeth were presented in the patient. In his twin sister, mild skeletal class 3 malocclusion with protruded mandible was observed but congenital missing teeth and microdontia were not observed. High-arched palate, narrow V-shaped maxillary arch compared to wide and ovoid mandibular arch and inverse relationship between the maxillary and mandibular intermolar width resulted in posterior crossbite were confirmed by model analysis of the patient. These were not observed in the twins. Behaviorally, poor cooperation during dental treatment because of mental retardation was observed in the patient.