• 한국전산구조공학회논문집
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• 제20권4호
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• pp.485-492
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• 2007

본 논문에서는 1편에서 얻어진 온도분포와 박리시간이력을 이용하여 지하박스구조물의 열응력을 산정하고 이에 기반한 열모멘트를 산청하였다. 또한 이때의 온도분포를 바탕으로 구조물의 열적비선형성을 고려한 극한모멘트를 산정하여 구조물의 내하력을 산정하였다. 그 결과 상부슬래브의 부모멘트 구간은 단면의 온도경사에 의해서 발생하는 열모멘트에 의해 지배받는 것으로 나타났다. 반면 정모멘트 구간은 박리에 의해 화염에 노출된 철근의 항복응력에 의해 지배받는 것으로 나타났다.

• 농촌계획
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• 제26권2호
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• pp.95-106
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• 2020

The Onishi model is an objective indicator which can be used to evaluate the relevance of city environmental management in regard to the capacities and processing status of existing urban infrastructure. This study is to analyze the facility carrying capacity and processing status of Jeju Island, a famous tourist site in South Korea. General variables covered by the Onishi model are considered, including water supply, wastewater treatment, waste disposal, and air pollution. Furthermore, the facility carrying capacities for transportation, such as airports and ports, as well as accommodations are assessed as variables pertinent to the characteristics of Jeju island. With the annual number of tourists exceeding that of residents on the island, more facilities for sewage treatment and waste disposal are required. Furthermore, transportation and accommodations used by tourists have already exceeded their capacity. For the future sustainability of Jeju Island, a plan will be needed for adjusting the volume of tourists based on the capacity of each relevant facility.

• Journal of the Korean Wood Science and Technology
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• 제45권6호
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• pp.728-736
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• 2017

In this study, the bending behavior of cross-laminated timber (CLT) connected by nails were investigated. Especially, the load-carrying capacity of the nail-jointed CLT under out-of-plane bending was predicted by the lateral resistance of the used nails. Three-layer nail-jointed CLT specimens and a nail connection were manufactured by 30 mm (thickness) ${\times}$ 100 mm (width) domestic species (Pinus koraiensis) laminas and Ø$3.15{\times}82mm$ nails using a nail-gun. Shear test for evaluating the nail lateral resistance and bending test for evaluating the load-carrying capacity of the nail-jointed CLT under out-of-plane bending were carried out. As a result, two lateral resistance of the used nail, the 5% fastener offset value and the maximum value, were 913 N and 1,534 N, respectively. The predicted load-carrying capacity of the nail-jointed CLT by the 5% offset nail lateral resistance was similar to the yield points on the actual load-displacement curve of the nail-jointed CLT specimens. Meanwhile, the nail-jointed CLT specimens were not failed until the tension failure of the bottom laminas occurred beyond the maximum lateral resistance of the nails. Thus, the measured maximum load carrying capacities of the nail-jointed CLT specimens, approximately 12,865 N, were higher than the predicted values, 7,986 N, by the maximum nail lateral resistance. This indicates that the predicted load-carrying capacity can be used for designing a structural unit such as floor, wall and roof able to support vertical loads in a viewpoint of predicting the actual capacities more safely.

• Tribology and Lubricants
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• 제29권1호
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• pp.13-18
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• 2013

Slider bearing is a widely used load-carrying element in the industry. While a large number of studies have investigated the effect of overall surface curvature, very few have considered sinusoidal surface. Recently, consideration of surface roughness/waviness or intentional wave design has been identified as an important issue in the manufacture of hard disk driver, mechanical seal, hydraulic machine, and etc. This study investigated the load-carrying capacity of a finite-width slider bearing with a wavy surface. Film thickness ratios, length-width ratio, ambient pressure, amplitude, and partial distribution were selected as the simulation parameters. The calculation results showed that the load-carrying capacity rapidly varied at small film thickness ratio, but the waviness near the area of minimum film thickness made much more influence with an increase in film thickness ratio. As the length-width ratio of bearing was increased, ambient pressure became more influential at small film thickness ratios. Furthermore a particular partial distribution of the wavy area led to higher load-carrying capacity than did the whole distribution. Consequently, the results of this study are expected to be of use in surface micro-machining of finite-width slider bearings.

• 환경영향평가
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• 제11권1호
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• pp.25-36
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• 2002

The purpose of this study is to assess the environmental carrying capacity of Chongju City for the environmental management and the urban growth management. The urban environmental carrying capacity assessment of the city by the index of ecological footprint(EF), shows that the ecosystem of the city has been overloaded and most of the deficiencies has come from outside of the city. The EF index, the area of land per capita required for production and consumption in the city, was 1.731 ha per capita in 1989 and 1.901 ha per capita in 1999. On the other side, the ecologically productive land is 0.0175 ha per capita. It means that every citizen owes 1.88 ha per capita to the ecosystem in 1999. The land consumption of the city has increased by 0.1705 ha per capita during the last 10 years. The capacity of infrastructure and the service supply estimated by the Onishi model does not exceed the demand of the city in 1999. But the rapidly increasing population and fast urban growth need the expansion of the capacity. The water supply capacity of the city appears to be sufficient in 1999, but the water supply demand will increase in the future. The capacity of sewage treatment facilities seems to be sufficient, but the higher level of sewage treatment facilities should be adopted for the improvement of water quality as the generation of sewage will increase and its characteristics will also make the wastewater treatment difficult. Due to the decrease of solid waste generated, the land fill capacity for solid waste disposal is not insufficient at present, but the capacity will be saturated in the near future. Therefore, the scientific management system of solid wastes should be introduced. The air quality of the city meets both the national air quality standard and WHO recommendation standard, but the strong regulation and control of automobile emission gas such as CO, $CO_2$, NOx and HC is required for clean air.

• 농업과학연구
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• 제44권3호
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• pp.400-408
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• 2017

This experiment was conducted to estimate the livestock carrying capacity per unit area of Hanwoo heifer with determine the quality of the forage by evaluating the productivity and nutritive value of spring seeding oats (Avena sative L.) according to different seeding and harvesting timings. Dry matter yields were the highest at 13.62 tons per ha when oat was seeded on March 15 and harvested on June 8 (p < 0.05), while the lowest yield of 6.29 tons per ha was obtained when seeded on February 25 and harvested on May 19 (p < 0.05). The highest crude protein yield of 1.27 tons per ha (p < 0.05) was obtained when seeded on March 5 and harvested on June 8. The total digestible nutrient yield was the highest at 7.38 tons per ha when harvested on June 8, the last harvest of the experiment (p < 0.05). In the northern part of Gyeongbuk province, spring seeding oats at the beginning of March, rather than in the middle of March, showed good annual livestock carrying capacity per unit area. According to harvest timing, the plot harvested on June 8 showed the highest livestock carrying capacity with an average of 6.53 heads (p < 0.05). In conclusion, in the northern part of Gyeongbuk province in spring, it is better to seed oat early in March and to harvest early in June to increase the livestock breeding capacity, considering dry matter productivity and feed value.

• 대한토목학회논문집
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• 제7권2호
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• pp.107-120
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• 1987

본(本) 논문(論文)은 실용적(實用的)인 이차(二次)모멘트 신뢰성이론(信賴性理論)을 사용하여 체계적(體系的)이며 이론적(理論的)인 내하력산정(耐荷力算定) 방법(方法)을 제안(提案)하는데 연구(硏究)의 주안점을 두고 있다. 그리고 교량내하력(橋梁耐荷力) 평가(評價)의 새로운 접근 방법을 본(本) 논문(論文)을 통하여 시도하고자 한다. 이 새로운 방법의 기본개념(基本槪念)은 극심한 주행(走行)트럭하중을 받는 교량(橋粱)의 내하력(耐荷力)의 신뢰성수준(信賴性水準)을 신뢰성지수(信賴性指數) ${\beta}$로 나타내는 데 있다. 본(本) 논문(論文)에서 제안(提案)된 내하력(耐荷力) 판정공식(判定公式)으로 몇 개의 실존교량(實存橋粱)에 대하여 적용하여 보았으며 그 결과(結果)를 현행(現行)의 내하력(耐荷力) 판정공식(判定公式)을 적용하여 얻은 결과(結果)와 비교(比較)하여 보았다. 신뢰성이론(信賴性理輪)에 기초한 교량내하력평가(橋粱耐荷力評價) 공식(公式)은 가까운 장래에 저항(抵抗)과 하중효과(荷重效果)에 대한 기초적(基礎的)인 통계자료(統計資料)가 확보되는 대로 현행(現行)의 내하력평가(耐荷力評價) 방법(方法)에 대치될 수 있을 것으로 판단된다.

• Earthquakes and Structures
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• 제12권1호
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• pp.23-34
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• 2017

Composite steel plate deep beam (CDB) is proposed as a lateral resisting member, which is constructed by steel plate and reinforced concrete (RC) panel, and it is connected with building frame through high-strength bolts. To investigate the seismic performance of the CDB, tests of two 1/3 scaled specimens with different length-to-height ratio were carried out under cyclic loads. The failure modes, load-carrying capacity, hysteretic behavior, ductility and energy dissipation were obtained and analyzed. In addition, the nonlinear finite element (FE) models of the specimens were established and verified by the test results. Besides, parametric analyses were performed to study the effect of length-to-height ratio, height-to-thickness ratio, material type and arrangement of RC panel. The experimental and numerical results showed that: the CDBs lost their load-carrying capacity because of the large out-of plane deformation and yield of the tension field formed on the steel plate. By increasing the length-to-height ratio of steel plate, the load-carrying capacity, elastic stiffness, ductility and energy dissipation capacity of the specimens were significantly enhanced. The ultimate loading capacity increased with increasing the length-to-height ratio of steel plate and yield strength of steel plate; and such capacity increased with decreasing of height-to-thickness ratio of steel plate and gap. Finally, a unified formula is proposed to calculate their ultimate loading capacity, and fitting formula on such indexes are provided for designation of the CDB.

• Journal of Ecology and Environment
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• 제46권1호
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• pp.1-7
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• 2022

Background: In this study, we proposed that the population dynamics of non-native red-eared sliders (Trachemys scripta elegans) depends on the species' habitat extension and survivorship. We used a logistic equation with time-dependent habitat carrying capacity. In detail, the present carrying capacity depends on the red-eared slider population of the previous year. Anthropogenic activities such as the abandonment of previously captive red-eared sliders or the release due to religion customs would supply new habitats to the species. Therefore we assumed that anthropogenic spread increases the habitat carrying capacity. Based on the urbanization increase rate of 3% in Korea from 1980 to 2000, we assumed an annual spread of 3% to simulate the population dynamics of the red-eared slider. In addition, the effect on the population of an increase of natural habitats due to migration was simulated. Results: The close relationship between the distributions of non-native red-eared sliders and of urbanized areas demonstrates that urbanization plays an important role in providing new habitats for released individuals. Depending on the survivorship, the population of the red-eared slider in Korea increased 1.826 to 3.577 times between 1980 and 2000. To control population growth, it is necessary to reduce carrying capacity by reducing habitat expansion through prohibition of release into the wild ecosystem and careful managements of the wetland or artificial ponds. Changes in the habitat carrying capacity showed that the population fluctuated every other year. However, after several years, it converged to a consistent value which depended on the survivorship. Further, our results showed that if red-eared sliders expand their habitat by natural migration, their population can increase to a greater number than when they have a 99% survivorship in a fixed habitat. Conclusions: Further introductions of red-eared sliders into wetlands or artificial ponds should be prohibited and managed to prevent future spread of the species. Moreover, it is important to reduce the species' survivorship by restoring disturbed ecosystems and maintaining healthy ecosystems.

• 한국조경학회지
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• 제33권1호
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• pp.10-18
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• 2005

The main concept of social carrying capacity is based on the principle that 'there are limits to the number of users a given recreation site can accommodate in order to provide quality of recreation experience'. The quality of the experience is revealed as user's satisfaction and perceived crowding. In this respect, studies of social carrying capacity have been frequently conducted by measuring perceived crowding and satisfaction. The purpose of this study is to identify the variables affecting perceived crowding, and causality bet-ween satisfaction and perceived crowding. Four hundred seventy six visitors were selected at Naejangsan National park on peak day of autumn excursion through on-site survey. The collected data were applied by factor analysis for categorizing the research variables, and multiple regression for finding the causality among variables. The study results are follows. The expectation of crowding, as a normative variable for perceived crowding, are categorized by three factors; circulation, user facility, and landscape. The circulation factor is the most powerful affecting perceived crowding among three factor. The landscape factor, however, do not have statistical significance on perceived crowding. The causality between satisfaction and perceived crowding is found. Although this relation is significant in statistics, magnitude of the coefficient is very small. It might be interpreted that satisfaction cannot be predicted simply from a user's perception of crowding, but a multi-dimensional concept such as adaptation and coping behavior.