• The Korean Journal of Ecology
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• v.26 no.2
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• pp.53-58
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• 2003

Ever-growing recreation, tourism and ecotourism worldwide have become a significant factor of resource degradation in many protected areas. Managers of these areas are increasingly challenged to implement policies, strategies and actions that would protect the resource base while providing quality visitor experience. One major issue in managing protected area visitations is that of carrying capacity, or the question of "how much use is too much\ulcorner". Scientific studies of visitor impacts, often known as recreation ecology, has generated a knowledge base that provides valuable input to the visitor carrying capacity management process adopted by the U.S. National Park Service. This paper aims at (a) providing an overview of recreation ecology research and its application in managing visitor carrying capacity, and (b) examining the relevance of recreation ecology to East Asian protected areas with special reference to the visitor capacity issue.ity issue.

• Steel and Composite Structures
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• v.3 no.3
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• pp.199-212
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• 2003

An experimental investigation of lightweight aggregate and foamed concrete contribution to the ultimate strength capacity of square and rectangular steel tube sections is presented in this study. Thirty-four simply supported beam specimens, 1000-mm long, filled with lightweight aggregate and foamed concretes were tested in pure flexural bending to calculate the ultimate moment capacity. Normal concrete-filled steel tubular and bare steel sections of identical dimensions were also tested and compared to the filled steel sections. Theoretical values of ultimate moment capacity of the beam specimens were also calculated in this study for comparison purposes. The test results showed that lightweight aggregate and foamed concrete significantly enhance the load carrying capacity of steel tubular sections. Furthermore, it can be concluded from this study that lightweight aggregate and foamed concretes can be used in composite construction to increase the flexural capacity of the steel tubular sections.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.12
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• pp.715-726
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• 1999

This paper estimates the capacity of shunt type active power filters(APF) for harmonic/reactive power compensation with a thyristor converter load. The base capacity requirement of APF is defined for idealized converter load current waveform and the effect of commutation overlap on the APF capacity is examined. The APF capacity required for reactive power compensation in addition to the harmonic elimination is estimated to give maximum achievable power factor for various operating condition of the partially-loaded thyristor converter. The method of current limit of APF is introduced, and it is shown that the APF capacity can be considerably reduced by deliberately limiting the peak current while maintaining the filtering performance to meet the level std 519 regulation.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1012-1017
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• 2008

In this study, We examine closely the capacity spectrum method which a kind of displacement-based method evaluated by displacement of structure as an alternative to the load-based analysis method. The displacement-based method can easily review the strength of structure, seismic performance, ductility. Seismic performance by using capacity spectrum method is divided into design response spectrum and capacity spectrum. We can diagram design response spectrum by deciding the design seismic factor depending on performance target, site classification, seismic level, return period as UBC-97. Capacity spectrum is a load-displacement curve obtained by Push-over analysis considering the geometric parameter and the material parameter. We execute the seismic performance evaluation by using the capacity spectrum method to reinforced concrete pier which has been seismic design. As a result, We confirmed that there is a yield point and a ultimate point close by design response spectrum of UBC-97.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.2
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• pp.112-121
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• 2013

The calibration of resistance factor in reliability theory for limit state design of gravel compaction piles (GCP) requires a reliable estimate of ultimate bearing capacity. The static load test is commonly used in geotechnical engineering practice to predict the ultimate bearing capacity. Many graphical methods are specified in the design standard to define the ultimate bearing capacity based on the load-settlement curve. However, it has some disadvantages to ensure reliability to obtain an uniform ultimate load depend on engineering judgement. In this study, a well-fitting nonlinear regression model is proposed to estimate the ultimate bearing capacity, for which a nonlinear regression analysis is applied to estimate the ultimate bearing capacity of GCP and the results are compared with those calculated using previous graphical method. Affect the resistance factor of the estimate method were analyzed. To provide a database in the development of limit state design, the load test conditions for predicting the ultimate bearing capacity from static load test are examined.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.65-73
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• 2020

This study describes the evaluation results of pile length ratio and N value on the bearing capacity of drilled shafts in cohesionless soil. The bearing capacity ratio in Meyerhof's formula is affected only by the length ratio, and it is equally evaluated a sharing ratio of the end bearing capacity and the skin friction. NAVFAC's formula shows that the pile length influences both end bearing capacity and the skin friction, but pile length is also found to be a more influence factor on the end bearing capacity. Especially, it was found that the effect of pile length factor was larger than the effect of N value and pile diameter. FHWA's formula was evaluated to reflect the influence factor by skin friction more positively than other formulas at calculation the bearing capacity. It was also confirmed that the influence of the skin friction is larger when the ultimate bearing capacity is evaluated.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.8
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• pp.107-114
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• 2017

In this paper, a novel power factor compensation system based on voltage-controlled method is proposed for 3-phase 4-wire power system. The proposed voltage-controlled power factor compensation system generates a reactive power required for compensation by applying a variable output voltage by a slidac to a capacitor. In conventional power factor compensation system using the capacitor bank method, the power factor compensation error occurs depending on the load condition due to the limited capacity of the capacitors. However, the proposed system compensates the power factor up to 100% without error. In this paper, we have developed a voltage-controlled power factor compensation system and a control algorithm for 3-phase 4-wire power system, and verify its performance through simulation and experiments. If the proposed power factor compensation system is applied to an industrial field, a power factor compensation performance can be maximized. As a result, it is possible to reduce of electricity prices, reduce of line loss, increase of load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2807-2810
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• 2003

In this paper, we propose a fuzzy control method for improving the control performance by automatically tuning the scaling factor. The proposed method is that automatically tune the input scaling factor and the output scaling factor of fuzzy logic system through neural network. Used neural network is ADALINE (ADAptive Linear NEron) neural network with delayed input. ADALINE neural network has simple construct, superior learning capacity and small computation time. In order to verify the effectiveness of the proposed control method, we performed simulation. The results showed that the proposed control method improves considerably on the environment of the disturbance.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.373-382
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• 2007

In the vertical drain method, discharge capacity is generally one of the most important factor which affect on the estimation of the drain efficiency. However, adopting the drain considering discharge capacity only is not sufficiently considered method so that systematic criteria for adoption is necessary to choose the most suitable drain. Therefore, this study represents the application method considering behavior of the ground and vertical drain which is coupled together and ground improvement efficiency analyzing various cases of discharge capacity test performed in the recent soft ground improvement projects. According to the analysis, most drains tend to satisfy the required discharge capacity. It presents that deformed shape of the drains and well resistance estimation along the ground settlement, improvement efficiency by water content ratio along the depth and shear strength obtained after ground improvement should be considered altogether with the discharge capacity to select the proper drain. Also, appropriate adoption of drain material considering the ground condition is vital through analyzing the field measured data and comparing the result of the discharge capacity test as various vertical drain materials are being constructed continuously.

• 한국전기화학회:학술대회논문집
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• 1998.12a
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• pp.7-27
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• 1998

In order to design capacity of lithium ion battery, some calculations were carried out based on the characteristics of materials by the given battery shape and dimension. The principle of design was built by the interpretation of the correlation of material, electrochemical and battery factors. Parameters of materials are fundamental physical properties of constituent such as cathode. separator, anode, current collectors and electrolyte. Electrochemical factor includes potential pattern as a function of specific capacity, specific discharge capacity(or initial irreversible specific capacity or Ah efficiency) as a function of specific charge capacity and material balancing. Parameters of battery are dimension, construction hardware and performance. Battery capacity was simulated for a lithium cobalt dioxide as cathode and a hard carbon as anode to achieve 1100 mAh for the charge limit voltage of 4.2V, the weight ratio(+/-) of 2.4 and ICR18650. A fabricated test cell (ICR18650) which have weight ratio(+/-) of 2.4 discharged to 1093 mAh for the charge limit voltage of 4.2V. The sequential discharge capacity show good correspondence with designed capacity.