• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.253-262
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• 2005

Because the framed wall system using steel studs and runners with square steel tubes as structural elements is reinforced by the horizontal members called runners, it has more strength and load bearing capacity than the steel house wall system. Also, this system improves adiabatic and sound insulation performance by filling up the autoclaved lightweight concrete. We need to evaluate load bearing capacity according to the axial load and lateral load in case this system is applied in the housing system with 3~5 stories through variations in intervals for the runners under the placement effect of autoclaved lightweight concrete. Therefore, this study seeks to analyze axial and shear behavior of the framed wall system according to the placement effect of autoclaved lightweight concrete, and to secure safety for the vertical and lateral loads.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.21-24
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• 2011

최근 NAND 플래시 메모리는 가벼운 무게, 적은 전력소모, 온도 및 충격에 강한 내구성 때문에 하드디스크를 대체할 저장 매체로 주목 받고 있다. 하지만 NAND 플래시 메모리는 비대칭적인 읽기 쓰기 소거 연산 처리 속도와 제자리 갱신이 불가능한 물리적인 특징으로 인해 디스크 기반의 대표적인 인덱스 구조 중의 하나인 해시 인덱스 구조를 NAND 플래시 메모리 상에 구현하였을 때, 레코드가 빈번하게 삽입, 삭제, 갱신되면 대량의 제자리 갱신이 발생하여 플래시 메모리에서 느린 쓰기 연산과 소거 연산이 수행되어 성능이 저하된다. 본 논문에서는 이러한 성능 저하를 피하기 위하여 버켓 오버플로우 발생 시 분할 연산을 수행하지 않고, 최대한 지연시킴으로써 쓰기 연산을 줄이는 인덱스 구조를 제안한다. 또한, 각 버켓에 대한 오버플로우 버켓의 갱신 및 삭제 비율에 따라 적응적으로 오버플로우 버켓을 할당하여 추가적인 읽기 쓰기 연산을 줄인다. 본 논문은 기존의 해시 인덱스 구조를 예제 및 수식을 통하여 제안하는 인덱스 구조의 우수성을 보인다.

• Journal of Korean Society of Steel Construction
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• v.22 no.1
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• pp.75-85
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• 2010

A new freeform structure representing "Diagrid, Cantilevered, Tilted." which has been considered not only its distinctive appearance but also the structural advantages becomes one of the trends in tall building design. Especially in the Diagrid system, loads can be distributed through bracing frame so that it can be save the materials since it has more effective in the structure behavior. But the seismic performance index such as response modification factor is not clearly defined yet. Even though the diagrid is supposed to show higher seismic performance, it is underestimated due to the lack of reliable data. In this paper the response modification factor for the diagrid system is experimentally explored.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.458-466
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• 2023

Structures in our surroundings deteriorate over time due to environmental and chemical factors, resulting in a decrease in their performance. The primary causes of degradation in concrete structures are carbonation, salt damage, and freeze-thaw cycles. Various maintenance methods exist to address these degradation issues. However, research and technological development for existing maintenance methods have been ongoing, but the accuracy and effectiveness of repair materials and techniques have not been extensively validated. Therefore, in this study, we conducted a material performance evaluation of various manufacturers' repair materials. Based on this evaluation, we applied corrosion inhibitors and epoxy, which are the methods most closely related to crack repair, to assess the durability performance against carbonation, salt damage, and freeze-thaw cycles. The results show approximately a two-fold performance improvement against carbonation and salt damage, and a 5% enhancement in repair performance against freeze-thaw cycles. Thus, it is considered effective in preventing rebar corrosion when appropriate maintenance is carried out according to environmental and chemical factors during structural repairs.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.707-714
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• 2011

The inter-story drift ratio is used to evaluate the damage of buildings by the earthquake. This is known that as the inter-story drift ratio decreases, the seismic damage decreases. Although to reduce the inter-story drift ratio is the important issue in the seismic design, no practical inter-story drift design method has bean developed. This study presents an optimal inter-story drift design method to improve the seismic performance of the steel moment frames using the resizing algorithm. The objective function of the proposed method is to minimize the differences of the inter-story drift ratios so that the inter-story drift ratios of the building could be distributed evenly and be reduced. Because this method redesigns the sectional properties of structural members base on the displacement participation factor calculated by the unit-load method, this can improve the seismic performance of the structure without the iterative structural analysis. The efficiency of this algorithm was demonstrated by the application to steel moment frames.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.152-155
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• 2011

최근 폭발 등 극한하중에 대한 관심의 증대와 함께 방폭 및 연쇄붕괴방지를 위한 연구가 활발히 진행되고 있다. 이에, 본 연구에서는 폭발하중하의 강구조물의 손상도와 저항성능을 수치적으로 평가하고자 하였다. 이를 위해 구조물의 폭발피해경감을 위해 가장 중요한 구조부재인 기둥을 대상으로 폭발물과 구조물과의 이격거리를 달리하여 폭발하중을 적용하였다. 유한요소해석을 수행한 결과를 토대로 기둥의 손상도와 잔여압축강도를 비교하고 관계를 도출하였다. 본 연구의 목적은 폭발에 의해 기둥이 손상된 경우 구조물 전체의 연쇄붕괴저항성능에의 손상된 기둥의 기여도를 평가하는 것이다.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.2
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• pp.49-57
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• 1997

It is necessary to conduct researches about seismic design and analysis to protect various structures from earthquakes which are one of the most destructive natural disaster to human civilization. To assess the seismic capacity of structure, not only analytical but also experimental researches are important. Currently, pseudodynamic test known as computer-actuator on-line test is one of the available test methods to assess seismic capacity of structure without using shaking table. In this paper seismic capacity of simple one-degree of freedom structure was estimated by pseudodynamic test. Good agreement between the experimental and analytical results was obtained. Better results would be obtained when more sophisticated measuring and controlling instruments are available.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.71-77
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• 2002

We consider the simultaneous slewing and vibration suppression control problem of an idealized structural model which has a rigid hub with two cantilevered flexible appendages and finite tip masses. The finite clement method(FEM) is used to obtain linear finite dimensional equations of motion for the model. In the linear quadratic regulator(LQR) problem, a simple method is introduced to provide a physically meaningful performance index for space structure models. This method gives us a mathematically minor but physically important modification of the usual energy type performance index. A numerical procedure to solve a time-variant LQR problem with inequality control constraints is presented using the method of particular solutions.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.873-882
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• 1998

The parallel database machine approach is currently widely and successfully used. There are four major architectures which are used in this approach: shared-nothing architecture, shared-evertying architecture, shared-disk architecture, and hybrid architecture. In this paper, we use an analytical model to evaluate the performance of these database machine architectures. We define an abstract model for each type of database machine design to obtain performance equatons describing the execution times with respect to the hybrid hash join poeration. Using the performance equations, we evaluate the execution times of the various database machine design models.

• Composites Research
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• v.35 no.6
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• pp.463-468
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• 2022

The high porosity of the infill pattern of carbon chopped fiber-reinforced Nylon composite structures fabricated by the fused filament fabrication (FFF) type 3D printers determines the mechanical performance of the printed structures. This study experimentally evaluated the mechanical performance of Onyx composite specimens fabricated with a rectangular infill structure under the hot-pressing condition to improve the mechanical properties by reducing the porosity of the infill pattern of the printed structure, and evaluated the best mechanical performance. The hot-pressing conditions (145℃, 4 MPa, 12 min) that induce the most appropriate mechanical properties were found. As a result of microscopic observation, it was confirmed that the infill porosity of the composite specimens subjected to post hot-pressing treatment was effectively reduced. In order to confirm the mechanical performance of the post-treated specimen, a tensile test and a three-point bending test were performed with a control specimen without post-treatment and a specimen printed with the same density and dimensions after post-treatment to evaluate the mechanical properties. As a result of comparison, it was confirmed that the mechanical properties were effectively improved when the post-treatment of hot-pressing was performed.