• 한국초지조사료학회지
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• 제23권2호
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• pp.129-134
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• 2003

본 시험은 2000년 4월부터 8월까지 충남대학교 생명과학대학내 부속 실험축사에서 수행하였다. 시험에 공시된 목초는 1999년에 경운초지 조성방법으로 조성된 상번초형 혼파초지(tall type mixtures, 파종비율: orchardgrass, Potomac 40+ tall fescue, Fawn 20+ Festulolium braunii, Paulita 10 + perennial ryegrass, Reveille 10+timothy Climax 10+red clover, Kenblue 5+alfalfa, Vernal 5%)와 상ㆍ하번초형 혼파초지{tall+short type mixtures, 파종비율: orchardgrass, Potomac 40+tall fescue, Fawn 20+Kentucky bluegrass, New port(turf type) 10+ redtop, Barricuda(turf type) 10+perennial ryegrass, Palmer III (turf type) 10+red fescue, Flyer II(turf type) 5+white clover, Regal 5%}에서 수확된 1번초(2000년 4월 22일)로 한국재래산양을 이용하여 초지 혼파유형에 따른 목초의 이용성을 비교분석하기 위하여 시험을 실시하였고 얻어진 결과는 다음과 같다. 1) 1일 체중 kg당 건물섭취량은 상ㆍ하번초형 혼파초지가 28.6g으로 상번초형 혼파초지의 27.9g에 비하여 다소 높았으나 유의적인 차이는 없었다. 건물, cellular constituent, NDF 및 ADF 소화을은 상ㆍ하번초형 혼파초지가 상번 초형 혼파초지에 비하여 역시 높은 편이었으나 유의적인 차이는 나타나지 않았다. 2) 체내에 축적된 질소율(외관상의 생물가)은 상ㆍ하번초형 혼과초지가 54.5%으로 상번초형 혼파초지의 53.7%보다 높았으나 유의적인 차이는 인정되지 않았다. 3) 외관상 대사에너지의 축적률은 상ㆍ하번 초형 혼파초지가 59.4%으로 상번초형 혼파초지의 58.2%보다 약간 높은 편이었으나 유의적인 차이는 인정되지 않았다. 따라서, 산양에 의한 목초의 이용성은 두 혼파 초지간에 큰 차이가 없는 것으로 나타나, 혼파초지내 turf type 초류도 사초자원으로써 이용가치가 있다고 하겠다.

• 아시안잔디학회지
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• 제23권2호
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• pp.295-306
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• 2009

우리나라 골프장에 조성된 한지형 잔디 5종류 48품종에 대하여 품질을 평가하였다. 자연적으로 발생한 병은 브라운팻취병 뿐이었다. Fine fescue 품종은 봄철에 브라운팻취병이 발생하여 피해가 가장 큰 반면, bentgrass 종은 가을철 발병이 심하였으나, 품종 간에 대한 유의성의 차이는 없었다. 11월에 엽록소 함량이 가장 높은 종은 tall fescue와 perennial ryegrass 이었으며, 품종 간에 유의성의 차이를 보인 종은 tall fescue, kentucky bluegrass 및 fine fescue 이었다. 잔디색도에서도 역시 종간에 유의성이 있는 차이를 보였다. perennial ryegrass 종이 잔디색도에서 가장 높았으며, kentucky bluegrass 종과 tall fescue 종이 그 다음으로 높은 것으로 조사되었다. 잔디색도에 대한 품종 간에 높은 유의성의 차이를 보이는 종은 kentucky bluegrass, tall fescue 및 fine fescue이었다. 생체중은 잔디 종류 간에 유의성 차이는 없었지만, 뿌리 길이에서는 종간에 유의성 차이를 볼 수 있었다. 뿌리길이는 tall fescue 종이 가장 길었다. 생체중에 대한 품종간에 유의성의 차이를 보인 종은 kentucky bluegrass, bentgrass 및 tall fescue 이었다. 본 시험의 1년 결과로 볼 때 잔디의 생육과 품질은 각 종과 품종 간에 큰 차이가 있음을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제51권1호
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• pp.131-140
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• 2014

This study focuses on seismic behaviour of tall piers characterized by high slender ratio. Two analysis models were developed based on elastic-plastic hinged beam element and elastic-plastic fiber beam element, respectively. The effect of the division density of elastic-plastic hinged beam element on seismic demand was discussed firstly to seek a rational analysis model for tall piers. Then structural seismic behaviour such as the formation of plastic hinges, the development of plastic zone, and the displacement at the top of the tall piers were investigated through incremental dynamic analysis. It showed that the seismic behaviour of a tall pier was quite different from that of a lower pier due to higher modes contributions. In a tall pier, an additional plastic zone may occur at the middle height of the pier with the increase of seismic excitation. Moreover, the maximum curvature reaction at the bottom section and maximum lateral displacement at the top turned out to be seriously out of phase for a tall pier due to the higher modes effect, and thus pushover analysis can not appropriately predict the local displacement capacity.

• 국제초고층학회논문집
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• 제9권3호
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• pp.245-253
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• 2020

With the ever-increasing height of timber buildings, the complexity of timber as a structural material gives rise to behaviors not previously studied by engineers. An urgent call is needed regarding their performance in damage scenarios: activating alternative load paths in tall timber buildings is not the same as in tall buildings made with steel and concrete. In this paper we propose a robustness framework covering all building materials, whose application in timber may lead to new conceptual designs for the next generation of tall timber buildings. Qualitatively, the importance of building scale and the distinction between localized and systematic exposures are discussed, and how existing supertall structures can be an example for future generations of tall timber buildings. Quantitatively, the robustness index is introduced alongside a method to calculate the performance of a given building regarding robustness, in order to find the most cost-effective structural solutions for improved robustness. A three-level application recommendation is made, depending on the importance of the building in question. Primarily, the paper highlights the importance of conceptual design to achieve structural robustness and encourages the practicing engineering community to use the proposed framework to quantitatively come up with the new generation of tall timber buildings.

• 국제초고층학회논문집
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• 제2권3호
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• pp.213-228
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• 2013

Tall buildings have been traditionally designed to be symmetric rectangular, triangular or circular in plan, in order to avoid excessive seismic-induced torsional vibrations due to eccentricity, especially in seismic-prone regions like Japan. However, recent tall building design has been released from the spell of compulsory symmetric shape design, and free-style design is increasing. This is mainly due to architects' and structural designers' challenging demands for novel and unconventional expressions. Another important aspect is that rather complicated sectional shapes are basically good with regard to aerodynamic properties for crosswind excitations, which are a key issue in tall-building wind-resistant design. A series of wind tunnel experiments and numerical simulation have been carried out to determine aerodynamic forces and wind pressures acting on tall building models with various configurations: corner cut, setbacks, helical and so on. Dynamic wind-induced response analyses of these models have also been conducted. The results of these experiments have led to comprehensive understanding of the aerodynamic characteristics of tall buildings with various configurations.

• 국제초고층학회논문집
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• 제8권1호
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• pp.57-69
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• 2019

After decades of high-speed development, designing tall buildings as critical components of urban habitat, rather than simply standing aloof from their environments, has become an important concern in many Asian cities. Nevertheless, the lack of quantitative understanding cannot support efficient architectural design or urban renewal that targets better place-making. This study attempts to fill the gap by providing a typological approach for measuring the social impact of tall buildings' ground conditions: that is, public space, podiums, and interfaces. The central business districts (CBD) of three Asian cities, Shanghai, Hong Kong, and Singapore, were selected as cases. Typical patterns and categories of lower-level public spaces among the three CBDs were abstracted via typological analyses and field study. The following evaluation is achieved through the analytic hierarchy process (AHP). This quantified approach helps to provide a visualization of high or low positive social impacts of tall buildings' lower-level public spaces among the three cases. This study also helps to suggest a design code for tall buildings aimed at a more human-oriented urban habitat.

• 국제초고층학회논문집
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• 제11권4호
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• pp.265-276
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• 2022

Double-Skin Facades (DSF) on tall buildings are becoming increasingly common in urban environments due to their ability to provide architectural merit, passive design, acoustic control and even improved structural efficiency. This study aims to understand the effects of porous DSF on the aerodynamic characteristics of tall buildings using wind tunnel tests. High Frequency Force Balance and pressure tests were performed on the CAARC standard tall building model with a variable porous DSF on the windward face. The introduction of a porous DSF did not adversely affect the overall mean forces and moments experienced by the building, with few differences compared to the standard tall building model. There was also minimal variation between the results for the three porosities tested: 50%, 65% and 80%. The presence of a full-height porous DSF was shown to effectively reduce the mean and fluctuating wind pressure on the side face of the building by about 10%, and a porous DSF over the lower half height of the building was almost as effective. This indicates that the porous DSF could be used to reduce the design load on cladding and fixtures on the side faces of tall buildings, where most damage to facades typically occurs.

• 한국초지조사료학회지
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• 제17권2호
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• pp.157-166
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• 1997

This study was carried out with aim to find out a tall fescue cultivar which is palatable and resistant to hot climate, and a white clover cultivar which is less competitive with other grasses. Pastures with 3 treatments (TI: Fawn, tall fescue + Regal, white clover + orchardgrass + perennial ryegrass, T2: Roa, tall fescue + Regal, white clover + orchardgrass + perennial ryegrass, T3 : Roa, tall fescue + Tahora, white clover + orchardgrass + perennial ryegrass) were established by oversowing. Under continuous grazing, dry matter yield, soil characteristics, botanical composition and nutrient contents of forages were investigated during the grazing seasons 60m 1994 to 1996. No significant difference were found in establishment percents, physical and chemical characteristics of soil, and nutrient contents of forages between 3 treatments(P>0.05). Dry matter yield of TI, T2 and T3 were 24,188, 23,827 and 23,578kg/ha, respectively. Fawn and Roa, tall fescue cultivars occupied 6.1 and 4.8% of the total plants in 1994, 14.4 and 11.5 % in 1995, and 28.4% and 17.7% in 1996, respectively. These results indicate that Fawn, tall fescue dominantly occupied with time more than Roa, tall fescue. There were no differences in percentage of Regal and Tahora, white clover cultivars(P > 0.05), showing 4.2 and 2.4% in 1994, 16.1 and 17.3% in 1995, and 2.4 and 1.0% in 1996, respectively. The percentage of orchardgrass on mixed pasture decreased after summer season of high temperature, but percentage of Roa, tall fescue slowly increased with time firom 1994 to 1996.

• 국제초고층학회논문집
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• 제5권4호
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• pp.251-262
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• 2016

Tall Buildings have been one of the most prominent symbols of economic growth for nearly a century. Yet, in the aftermath of the tragedies of September 11, "signature" Tall buildings have become the focus of much debate. The structural systems today are undergoing a major evolution to address the ability of providing flexibility in the design and use of the building together with sustainability (Green) and cost-effective system. This paper describes a new invented structural system, evolutionary structural analysis and design of Tall buildings, which involves the entire analysis process, including conceptual and design stages and comparison with the existing Tall building. This study presents an new innovative structural system, Beehive (Hexagrid), for Tall buildings. The final results are achieved by modeling an 80 story Tall building with the optimized angle and topology of hexagon members by using a computer analysis, ETABS finite element analysis. The objective function of this system is to use one structural system in order to both maximize Eigen frequency for resisting dynamic responses and minimize mean compliance for static responses. Finite element analysis is carried out by using standardized materials. Optimal Hexagrid topologies with the highest stiffness are finally determined to resist both static and dynamic behaviors. Holistic design integration approaches between structures and facades to save energy for environmental control are studied. Innovative design ideas to control structural motion as well as to utilize that motion to harness energy are discussed. Considering abundant emergence of tall buildings all over the world in recent years, the importance of the studies presented in this paper cannot be overemphasized for constructing more sustainable built environments.

• Architectural research
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• 제21권4호
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• pp.91-98
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• 2019

In modern times, numerous cities are competing to create the unique skyline adjacent to the water. Tall buildings located across the river have a great contribution to the skyline of a riverfront city and can be a precious asset for the city. Moreover, in several cities, tall buildings and their impact on the urban skyline are a matter that should be considered and regulated in urban design. Therefore, as a prominent element in a larger visual setting of the city, tall buildings should improve the visual quality of the skyline rather than diminish that quality. This research attempts to provide an objective method to analyze the visual quality of the skyline made by a group of tall buildings through their feature of heights and spatial arrangement from riverfront views. The analysis is determined by the design variables of building heights variation, heights transition, density, and spacing of a group of tall buildings. A comparative case study of tall buildings in Yeouido and Lujiazui was conducted to prove the effectiveness of the analysis. The proposed method can be used in a simple way in the quantitative approach to quantify the visual quality of the skyline. In conclusion, Yeuido's skyline is not quite interesting from the riverfront view in terms of height variation and continuity of the skyline view because they are dispersed. Conversely, Lujiazui's skyline from the riverfront vantage points has a good quality in all aspects of the feature of height and spatial arrangements of tall buildings cluster. These factors can be used for the urban designer on how proposed tall buildings within the cluster should appropriately respond to adding image on the skyline.