• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
• /
• 제25권1호
• /
• pp.57-81
• /
• 1997

Numerical prediction of nocturnal thermal high in summer of the 1995 near Taegu city located in a basin has been carried out by a non-hydrostatic numerical model over complex terrain through one-way double nesting technique in the Z following coordinate system. Under the prevailing westerly winds, vertical turbulent fluxes of momentum and heat over mountains for daytime hours are quite strong with a large magnitude of more than $120W/\textrm{m}^2$, but a small one of $5W/\textrm{m}^2$ at the surface of the basin. Convective boundary layer (CBL) is developed with a thickness of about 600m over the ground in the lee side of Mt. Hyungje, and extends to the edge of inland at the interface of land sea in the east. Sensible heat flux near the surface of the top of the mountain is $50W/\textrm{m}^2$, but its flux in the basin is almost zero. Convergence of sensible heat flux occurs from the ground surface toward the atmosphere in the lower layer, causing the layer over the mountain to be warmed up, but no convergance of the flux over the basin results from the significant mixing of air within the CBL. As horizontal transport of sensible heat flux from the top of the mountain toward over the basin results in the continuous accumulation of heat with time, enhancing air temperature at the surface of the basin, especially Taegu city to be higher than $39.3^{\circ}C$. Since latent heat fluxes are $270W/\textrm{m}^2$ near the top of the mountain and $300W/\textrm{m}^2$ along the slope of the mountain and the basin, evaporation of water vapor from the surface of the basin is much higher than one from the mountain and then, horizontal transport of latent heat flux is from the basin toward the mountain, showing relative humidity of 65 to 75% over the mountain to be much greater than 50% to 55% in the basin. At night, sensible heat fluxes have negative values of $-120W/\textrm{m}^2$ along the slope near the top of the mountain and $-50W/\textrm{m}^2$ at the surface of the basin, which indicate gain of heat from the lower atmosphere. Nighttime radiative cooling produces a shallow nocturnal surface inversion layer with a thickness of about 100m, which is much lower than common surface inversion layer, and lifts extremely heated air masses for daytime hours, namely, a warm pool of $34^{\circ}C$ to be isolated over the ground surface in the basin. As heat transfer from the warm pool in the lower atmosphere toward the ground of the basin occurs, the air near the surface of the basin does not much cool down, resulting in the persistence of high temperature at night, called nocturnal thermal high or tropical night. High relative humidity of 75% is found at the surface of the basin under the moderate wind, while slightly low relative humidity of 60% is along the eastern slope of the high mountain, due to adiabatic heating by the srong downslope wind. Air temperature near the surface of the basin with high moisture in the evening does not get lower than that during the day and the high temperature produces nocturnal warming situation.

• 지식경영연구
• /
• 제23권1호
• /
• pp.203-225
• /
• 2022

글로벌 OTT(Over the Top) 서비스의 국내 진출이 늘어나고 기존 플랫폼 개편이 활발히 이루어지면서 OTT 서비스 시장의 경쟁이 더 치열해지고 있다. 초호화 콘텐츠를 보유한 막강한 경쟁자들이 계속해서 시장에 뛰어들고 있고 사람들의 니즈도 다양해짐에 따라 지속적인 수익 창출을 위해 가입자의 이탈을 막기 위한 OTT 서비스 플랫폼의 다양한 노력이 요구된다. 이에 본 연구는 기대일치모델을 기반으로 OTT 서비스 특성이 지속이용의도에 미치는 영향을 실증분석을 통해 살펴보고자 하였다. OTT 서비스 이용 경험이 있거나 현재 이용 중인 개인을 대상으로 총 386부의 설문을 수집하여 AMOS24를 사용하여 분석을 진행하였다. 연구결과, 플랫폼 품질 우수성을 제외한 콘텐츠 큐레이션, 콘텐츠 풍부성, 시청 능동성은 기대일치에 유의한 영향을 미치는 것으로 나타났다. 기대일치는 지각된 유용성과 사용자만족에 유의한 영향을 미쳤으며, 지각된 유용성은 사용자만족에 영향을 미치고, 사용자만족은 OTT 서비스 지속이용의도에 유의한 영향을 미치는 것으로 나타났다. 마지막으로 가격공정성은 기대일치와 사용자만족, 지각된 유용성과 사용자만족, 사용자만족과 OTT 서비스 지속이용의도 간의 관계를 강화해주는 것으로 나타났다. 본 연구의 결과는 OTT 서비스 사업자의 수익 창출에 가장 직접적인 영향을 미치는 가입자 유지를 위한 서비스와 콘텐츠 개발에 유용한 정보를 제공할 것으로 기대한다.

• 한국작물학회지
• /
• 제7권1호
• /
• pp.103-115
• /
• 1969

다수확 비료체계의 확립을 위하여 추비기 및 추비바업이 소맥의 수량요인에 미치는 영향에 관하여 시험한 결과를 요약하면 다음과 같다. 1. 배비구는 보비구에 비하여 수수 1수립수 및 수량이 높았으나 통계적 유의차는 보이지 않았다. 이는 저온 건조한 기상조건으로 말미암아 비료의 흡수 소화가 원활하지 못하였기 때문일 것이다. 2. 질소추비량의 1/3을 출수기에 토양시비 한 것은 6～7% 감소되었다. 3. 질소추비량의 1/3을 출수기에 요소엽면산포한 것은 4～6% 증수하였으며 1수립수와 천립중이 증대되었다. 4. 추비시기는 3월중하순이 가장 증수되었다. 유효경비율과 수중이 훨씬 크고 간장, 수장, 수수, 1수립수 및 천립중도 약간 컸다.

• 한국정보과학회논문지:데이타베이스
• /
• 제36권3호
• /
• pp.189-197
• /
• 2009

Top-k 질의는 많은 센서 네트워크 응용 분야에서 중요하게 사용된다. 기존에 제안된 필터 기반의 Top-k 질의 처리 기법은 질의 결과에 영향을 미치는 값만을 수신하기 위해 각 센서 노드의 측정 허용 범위를 필터로 설정함으로써 센서 데이타의 전송 횟수를 줄인다. 하지만, 센서 데이타의 재검증과 필터의 재배포 과정에서 추가적인 에너지를 소모한다. 또한, 질의 결과값이 빈번히 변경될수록 필터의 재배포 횟수가 증가하여 에너지의 소모가 더욱 증가한다. 본 논문에서는 Top-k 질의를 처리하기 위해서 측정한 데이타를 기반으로 우선 순위를 결정하고, 우선 순위에 따라 최소한의 센서 데이타를 수집하는 새로운 Top-k 질의 처리 기법을 제안한다. 제안하는 기법의 우수성을 보이기 위해서 시뮬레이션을 통한 성능 평가를 수행하였으며, 그 결과 기존 필터 기반의 기법에 비해 네트워크의 수명이 크게 향상되었다.

• 천문학회보
• /
• 제44권2호
• /
• pp.50.3-50.3
• /
• 2019

We show that dynamical evolution in a strong (Galactic Centre-like) tidal field can create clusters that would appear to have very top-heavy IMFs. The tidal disruption of single star forming events can leave several bound 'clusters' spread along 20~pc of the orbit within 1-2 Myr. These surviving (sub)clusters tend to contain an over-abundance of massive stars, with low-mass stars tending to be spread along the whole 'tidal arm'. Therefore observing a cluster in a strong tidal field with a top-heavy IMF does not mean the stars formed with a top-heavy IMF.

• 한국CDE학회논문집
• /
• 제7권1호
• /
• pp.42-56
• /
• 2002

Presented in this study is a top-down functional requirement analysis procedure and the desired functionalities for PDM system development, and the benefits of top-down approach over a conventional bottom-up approach is also shown. For the purpose of top-down requirement analysis for PDM system, this study proposes 4P modeling view. 4P modeling view is defined as a modeling perspective for classifying functional requirements and integrating product-related information objects that must be man-aged within PDM systems. Based on 4P modeling templates, benchmarking analysis of commercially major PDM products is conducted and as a result of this analysis, this study suggests desired functionalities for PDM system.

• 복식
• /
• 제34권
• /
• pp.169-182
• /
• 1997

Focusing on khotan located in the southern Silk Route which was one of the most important kingdoms in the Tarim Basin this study attempts to examine the changes of costume in Khotan by compar-ing the costumes in the painted panel showing the story of silk princess with the excavated costumes from ancient tombs. Furthermore this study attempts to inves-tigate the impacts of cultural exchange be-tween China and its western neighboring country Eastern and Western Turkestan on costume. Excavated costumes from the Shanpula ancient tomb in the region of Khotan and from ancient Niya in the esat-ern border of Khotan and discoveries from Rawak and Dandan-oilik near by Yotkan the ancient capital of Khotan are exam-ined. Basic Khotan's costume was the two piece style of tops and trousers. Over the basic costume wearing a top wear with half sleeves was popular. Skirt was worn by women. Even though there were many kinds tops were classified into the two types kaftan and tunic. Thouth Khotan maintained a association with China for a long time the style of Khotan costume had imbued to China. Top wear with half sleeves was worn frequently in Khotan. Also in China top wear with half sleeves was worn as over-wear which was called ban-xiu ban-bi bei-zi Costume style of China is covering the body profoundly and wrapping front edge toward the right. The types of chi-nese top wear with half sleeves for exam-ple round-neck·confronting front edge crossing-neck·confronting front edge tu-nic type discord with the traditional chi-nese costume style There were many cas-es that half sleeved top wear was worn as over wear in T'ang dynasty. The phenom-enon was due to the prevalence of 'ho' (foreign) and half sleeved top wear was introduced by the countries to the west of China Khotan. A round neck garment was a general type for the men of cuntries to the westof China. Also Chinese wore round neck garment since South and North Dynasty The type of Chinese round neck garment was not tunic but kaftan. From costume relics and ancient paintings the type of Khotan's round neck garment was tunic which was recorded on the Chinese histori-cal documents as " guan-tou-shan" that is tunic the type of persian costume, Even thgough the painted panel showing the sto-ry of silk princess was made in the it me when Turks was a dominion on Central Asia Khotan's costume style was not changed toward Turk's costume style and remained tunic style.

• 방송공학회논문지
• /
• 제23권4호
• /
• pp.549-558
• /
• 2018

360 VR(Virtual Reality) 비디오와 같이 고품질의 비디오를 기존 케이블 망에서 IPTV 또는 OTT(Over the Top) SettopBox과 같은 저사양 미디어 서비스 기기를 통해 저지연 라이브 스트리밍 서비스를 할 수 있도록 MPEG DASH(Dynamic Adaptive Streaming over HTTP) 기반의 스트리밍 서버를 설계하고 구현하였다. 또한, 서버 응답 지연 시간을 줄이기 위해 스트리밍 영상 파일(MPD, Segment Files)을 메모리상에 캐싱 하여 서비스 할 수 있는 관리 프로세스를 설계하고 적용하였다. 그리고 실험을 통해 bitrate가 50,000kbps 이상이고, 8K@60P 급의 고품질 분할 영상 스트리밍을 지원하는 것을 확인하였다

• 소성∙가공
• /
• 제19권8호
• /
• pp.494-501
• /
• 2010

The main objective of this study is to examine the sensitivity of calibration curves of FEA of ring compression test to frictional shear factor. Ring compression test has been investigated by measuring dimensional changes at different positions of ring specimen and they include the changes in internal diameter at the middle and top section of the specimen, outer diameter at the middle and top section, surface expansion at the top surface, respectively. Initial ring geometries employed in analysis maintain a fixed ratio of 6 : 3 : 2, i.e. outer diameter : inner diameter : thickness of the ring specimen, which is generally known as 'standard' specimen. A rigid plastic material for different work-hardening characteristics has been modeled for simulations using rigid-plastic finite element code. Analyses have been performed within a definite range of friction as well as over whole range of friction to show different sensitivities to the interfacial friction for different ranges of friction. The results of investigation in this study have been summarized in terms of a dimensionless gradient. It has been known from the results that the dimensional changes at different positions of ring specimen show different linearity and sensitivity to the frictional condition on the contact surface.

• 한국작물학회지
• /
• 제43권4호
• /
• pp.269-272
• /
• 1998

Characteristics of seed and plant growth of the nine local collections of the medicinal plant, Agastache rugosa were evaluated. Seed size of the collection from Garyungsan was larger than the others. Seeds of Damyang collection were the smallest in size. Seeds of the collections were mostly oval shaped. There were no differences between brown and black seed coat color groups in seed width, ratio of seed length to seed width and 1,000 seed weight. Stem lengths of Garyungsan and Bongpyung collections were 99.9 and 95.6 cm, respectively, and were longer than Damyang and Jindo collections. Garyungsan collection had long leaf shape. Leaf size was the smallest for Damyang collection, but was the largest for Bongpyung collection. Inflorescence length of Mokpo collection (15.6 cm) was longer than the average over all collections (12.3 cm). Damyang collection was the shortest (10.1 cm) in inflorescence. Top dry weight of each collection from Soonchun, Bongpyung, Mokpo, Jindo, and Gurye was greater than the average over all collections (20.38 g/plant). Jinju and Damyang collections had less top dry matter than others. There was no difference in the growth traits examined between brown and black seed coat groups. The brown seed group was greater in leaf weight than the black seed group. However, these two groups were not different in stem and inflorescence weight. Collections of A. rugosa from Bongpyung, Soonchun, and Mokpo were promising for commercial cultivation because of their great top dry weight, especially in leaf and inflorescence.