• Steel and Composite Structures
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• 제20권3호
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• pp.599-621
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• 2016

In order to study the working mechanism of rectangular steel-concrete composite columns subjected to compression-bending load and further determine the seismic performance index, a bottom strengthened rectangular steel reinforced concrete (SRC) column with concealed steel plates and a bottom strengthened rectangular concrete filled steel tube (CFST) columns were proposed. Six column models with different configurations were tested under horizontal low cyclic loading. Based on the experiments, the load-bearing capacity, stiffness and degradation process, ductility, hysteretic energy dissipation capacity, and failure characteristics of the models were analyzed. The load-bearing capacity calculation formulas for a normal section and an oblique section of bottom strengthened rectangular steel-concrete composite columns were pesented and a finite element (FE) numerical simulation of the classical specimens was performed. The study shows that the load-bearing capacity, ductility, and seismic energy dissipation capacity of the bottom strengthened rectangular steel-concrete composite columns are significantly improved compared to the conventional rectangular steel-concrete composite columns and the results obtained from the calculation and the FE numerical simulation are in good agreement with those from the experiments. The rectangular steel-concrete composite column with bottom strengthened shows better seismic behavior and higher energy dissipation capacity under suitable constructional requirements and it can be applied to the structure design of high-rise buildings.

• Geomechanics and Engineering
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• 제34권4호
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• pp.381-396
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• 2023

The present paper evaluates seismic bearing capacity of rock masses subjected to loads of strip footings using the upper bound method. A general formula was proposed to evaluate the seismic bearing capacity considering both the horizontal and vertical accelerations of the earthquake and the effects of footing embedment depth simultaneously. Modified Hoek-Brown failure criterion was employed for the rock mass. Some comparisons were made with the available solutions and the finite element numerical models to show the accuracy of the developed upper bound formulations. The obtained results show significant improvement compared to the other available solutions. By increasing the horizontal earthquake acceleration from 0.1 to 0.3, the bearing capacity was reduced by up to 39%, while the effect of the vertical earthquake acceleration depends on its direction. An upward acceleration in the range of zero to 0.2 results in an increase in the bearing capacity by up to 24%, while the downward earthquake acceleration has an adverse effect. Also, by increasing the embedment depth of the footing from zero to 5 times the footing width, the value of seismic bearing capacity was raised about 86%. The obtained results were presented as design tables for use in practical applications.

• Asian Journal of Business Environment
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• 제12권2호
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• pp.43-53
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• 2022

Purpose: This study aims to analyze the performance of local taxes in Indonesia through the estimation of tax capacity and tax effort, as well as classifying provinces based on the estimated value of tax capacity and tax effort. Research design, data and methodology: this study uses panel data of 34 provinces in Indonesia for the period of 2014-2018. The analytical method used in the tax capacity model is panel data regression to explain the factors that influence tax performance. Tax effort is estimated by the ratio of tax to tax capacity. Results: The results of the analysis show that gini ratio and regional expenditures have a significant positive effect on the tax ratio, while the share of GRDP in the manufacturing sector and HDI has a significant negative effect on the tax ratio. Based on the results, there are 19 provinces that have low tax capacity and 16 provinces that have low tax effort. Conclusions: The development of local tax performance tends to fluctuate with an average of 1.24 percent per year. Gini ratio and regional expenditure have a significant positive effect on the tax ratio, while the share of GRDP in the manufacturing sector and HDI have a significant negative effect on the tax ratio.

• 한국전자통신학회논문지
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• 제10권11호
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• pp.1271-1276
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• 2015

최근 발전원가가 높은 도서지역의 디젤발전을 신재생에너지로 대체하는 추세이다. 이에 따라 전라남도는 디젤발전기에 의존하여 섬에 전기를 공급하는 지역을 대상으로 태양광과 풍력 그리고 에너지 저장장치 등을 이용한 친환경에너지원을 통해 전기를 공급하는 에너지 자립섬 조성사업을 추진하고 있다. 하지만 신재생에너지원의 용량 설계는 환경적, 지형적 조건으로 부하에 100%로 대응할 용량의 신재생에너지원을 설치하기란 어렵다. 또한 경제성 있는 하이브리드시스템 최적 구성을 위해서는 설계 단계부터 기후조건과 부하패턴 분석을 통해 시스템 구성요소의 적절한 용량 설계와 효과적인 운영을 고려한 마이크로그리드 설계가 요구된다. 따라서 본 논문에서는 서남해안에 위치한 도서지역 중 300호 이상의 가구수를 갖고 증설이 요구되는 거문도를 대상으로 디젤 발전량 중 40%를 신재생에너지원으로 대치하는 하이브리드 발전시스템을 구성하여 최적조합과 용량산정 그리고 경제성에 대한 연구를 수행하고자 한다.

• 대한조선학회논문집
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• 제47권1호
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• pp.99-111
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• 2010

Recently, a very large vessel's maneuvering performance, rudder performance and rudder design's importance is considered to be an important subject. There have been few studies on the design process of rudder device before. The aim of this paper is to investigate a design process of rudder device and to propose a generalized design process of rudder device. Firstly, we investigated the rudder device design process of Korean major shipyards. And the differences of a torque calculation method, rudder section design, maneuvering performance examination method, etc were analyzed theoretically. Secondly, the design process of rudder device was divided into concept design, initial design and detail design. In concept design, a rudder area was estimated and its validity was examined. In initial design, rudder profile and design method has been selected through rudder form determination process. And principal dimension and steering gear capacity were determined. Maneuvering performance was also examined by simulation tool. In detail design, design criteria considered in rudder initial design has been investigated thoroughly. Also a rudder torque, rudder cavitation performance and rudder structure analysis were estimated. And maneuvering performance was also examined by model test. Finally, based on the results of investigation, the design process of rudder device was generalized and proposed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.278-283
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• 1997

This paper proposes a systematic design method for axial(or thrust) magnetic bearings using optimal design methodology. The objective of the optimal design is to minimize bearing volume. The constraints include the bearing load capacity, linearized bearing stiffness and damping, the magnetic flux density, and geometric relations. In order to obtain design values which can be applied to fabrication of bearings, branch and bound method was introduced in the postprocessing procedure of optimal design results. Verification of the proposed design methodology was perfomed by an example.

• 국제초고층학회논문집
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• 제10권3호
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• pp.165-171
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• 2021

Core-outrigger-mega frame system is used in Suzhou IFS with 95-story, 450 m-tall, which is beyond Chinese code limit. Besides simple introduction on design principle, structure system and analysis, key techniques including performance based design criteria, frame shear ratio, capacity check of mega column, human comfort criteria under wind induced vibration and TSD design were presented in details for reference of similar super tall building design.

• 한국전산구조공학회논문집
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• 제15권2호
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• pp.329-339
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• 2002

본 연구에서는 비선형 정적해석법인 능력스펙트럼 법을 이용하여 성능목표를 만족하기 위하여 필요한 점탄성 감쇠기를 설계하는 절차를 제시하였다. 점탄성 감쇠기의 적정 크기를 구하기 위해 목표 변위에서 필요한 유효감쇠 비를 구한 다음 구조물의 이력거동에 의한 등가감쇠 비와 고유감쇠 비를 이용하여 필요한 감쇠기의 감쇠를 구하였다. 점탄성 감쇠기를 설치할 경우에는 구조물의 감쇠뿐만 아니라 강성도 변화하기 때문에 반복계산이 필요하게 된다. 본 연구에서는 먼저 단자유도계에서 구조물의 설계변수를 변화시키면서 제안된 방법의 타당성을 검증하였다. 또한 10층의 철골조 건물에 적용하고 지진응답을 구하였다. 제안된 방법에 따라 설계된 감쇠기를 설치하고 수행한 시간이력해석 결과에 의하면 고려된 설계변수에 관계없이 목표변위를 만족하는 것으로 나타났다.

• 대한기계학회논문집
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• 제14권6호
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• pp.1391-1407
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• 1990

본 연구에서는 Kam과 Chang의 연구와 같이 판의 최소 처짐, 판의 최대 모달 에너지 감쇠비 및 최대 고유 진동수를 설계제한 조건으로 택하고 Watkins와 Morris가 사용한 순환 선형 계획법을 이용하여 혼합 적층 복합 재료판의 최적설계를 수행하였다.

• Steel and Composite Structures
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• 제29권2호
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• pp.231-242
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• 2018

As a lateral load resisting component, buckling restrained steel plate shear walls (BRW) have excellent energy dissipating capacity. Similar to thin steel plate shear walls, the mechanical behavior of BRWs depends on the boundary elements (adjacent beams and columns) which need adequate strength and stiffness to ensure the complete yielding of BRWs and the emergence of expected plastic collapse mechanism of frame. This paper presents a theoretical approach to estimate the design forces for boundary elements of beam-connected BRW (i.e., The BRW is only connected to beams at its top and bottom, without connections to columns) using a fundamental plastic collapse mechanism of frame, a force transferring model of beam-connected BRW and linear beam and column analysis. Furthermore, the design method of boundary beams and columns is presented. The proposed approach does not involve nonlinear analyses, which can be easily and efficiently used to estimate the design forces of beams and columns in a frame with BRWs. The predicted design forces of boundary elements are compared with those from nonlinear finite element analyses, and a good agreement is achieved.