• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.134-141
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• 1997

A geometrically non-linear finite element formulation of spatial cable networks is presented using three cable elements. Firstly, derivation procedures of tangent stiffness and mass matrices for the space truss element and the elastic catenary cable element, and the isoparametric cable element are summarized. The load incremental method based on Newton-Raphson iteration method and the dynamic relaxation method are presented in order to determine the initial static state of cable nets subjected to self-weights and support motions. Furthermore, static non-linear analysis of cable structures under additional live loads are performed based on the initial configuration. Challenging example problems are presented and discussed in order to demonstrate the feasibility of the present finite element method and investigate static non-linear behaviors of cable nets.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.803-808
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• 2007

LCCA module enabling to estimate LCC and analyze time-variant reliability index of a plate girder bridge was developed. The developed module was based on the designed data structure following the standardized methodology of ISO/STEP, LCCA module consisted of LCC estimation module, which is composed of six sub modules according to the cost category, and reliability index analysis module, which is composed of time-variant corrosion sub module, time-variant live load sub module, and element reliability analysis sub module, The effectiveness of the developed LCCA module was verified by estimating LCC and analyzing time-variant reliability index of a plate girder bridge on the basis of the constructed test database.

• Advances in concrete construction
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• v.3 no.2
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• pp.113-126
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• 2015

Holed-Incrementally Prestressed Concrete (H-IPC) girders are designed using the following new design concepts. At first, web openings reduce the self-weight of the girder, and also diffuse prestressing tendon anchorages. The reduced end anchoring forces decrease the web thickness of the end sections. Additionally, precast technology help to improve the quality of concrete and to reduce the construction period at the site. For experimentally verification, two 50 m full-scale H-IPC girders are manufactured with different concrete strength of 55 MPa and 80 MPa. The safety, stiffness, ductility, serviceability and crack development of H-IPC girder are measured and compared with each other for different strengths. Both girders show enough strength to carry live load and good stiffness to satisfy the design criteria. The experimental result shows the advantages of using high strength concrete and adopting precast girder. The test data can be used as a criterion for safety control and maintenance of the H-IPC girder.

• Journal of the Korea Society of Computer and Information
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• v.22 no.5
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• pp.11-19
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• 2017

In this paper, we propose a hypervisor for embedded systems based on ARM microprocessor. The proposed hypervisor makes it possible to run several real-time kernels concurrently on a single embedded system by virtualizing its microprocessor. With assistance of MMU, it supports virtual memory which enables each guest operating system has its own address space. Exploiting the fact that most embedded systems use memory-mapped I/O device, it provides a mechanism to distribute an external interrupt to virtual machines properly. It also achieves load balancing through live migration which moves a running virtual machine to other embedded system. Unlike other para-virtualization techniques, minor modifications are needed to run it on the hypervisor. Extensive performance measurement studies are conducted to show that the proposed hypervisor has enough potentiality of its real-world application.

• International Journal of High-Rise Buildings
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• v.3 no.2
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• pp.89-98
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• 2014

Employing tilted forms in tall buildings is a relatively new architectural phenomenon, as are the cases with the Gate of Europe Towers in Madrid and the Veer Towers in Las Vegas. This paper studies structural system design options for tilted tall buildings and their performances. Tilted tall buildings are designed with various structural systems, such as braced tubes, diagrids and outrigger systems, and their structural performances are studied. Structural design of today's tall buildings built with higher strength materials is generally governed by lateral stiffness. Tilted towers are deformed laterally not only by lateral loads but also by dead and live loads due to their eccentricity. The impact of tilting tall buildings on the gravity and lateral load resisting systems is studied. Comparative evaluation of structural systems for tilted tall buildings is presented.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1326-1331
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• 2006

The precast concrete deck is one of suitable solutions for replacement and new construction in urban area. However, the precast concrete deck could be a weak point of the steel plate girder bridges structurally due to the connections between precast panels in the longitudinal direction. Thereafter, it is necessary for improvement of durability and load carrying capacity to introduce the prestress force in the longitudinal direction Some cracks of connections at the precast concrete deck may be occurred due to live loads, the difference of temperature and long-term effects. The shrinkage and creep of concrete may significantly affect long-term behaviors which occur tensile stresses at the precast concrete deck of steel plate girder bridges. In this study, the time-dependant analysis program has been developed to determine the initial prestress force in the longitudinal direction considering loss of stress at the precast concrete deck. Also it has been estimated the initial prestress force by construction stages and shapes of girder.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.119-125
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• 2002

The concept of dwelling space is tend to be changed not only to have reasonable mobility but also to have high quality of indoor air with psychologicaa satisfaction and comfortable. Moreover, recent constructed buildings have a big problem because of exhausted pollution gas and particles from building materials. More serious problem occurs from its high air tightness reducing the ventilation for saving the energy and superior adiabatic insulators to have high heat efficiency. Indoor air quality in super high-rise dwelling house was investigated by measuring pollutants such as $CO_2,=;CO,\;MO_2,\;R_n,\;TSP,\;PM_{10}$, HCHO, Offensive ordor. Subjective evaluation of residential environment is processed for the inhabitants who live in research space by testing environmental load in accordance with environment morphology, exterior environmental factor and post occupancy correlation and influence of attention.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.385-388
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• 2009

건축물의 적재가연물 특성은 성능위주 화재안전설계를 수행함에 있어 중요한 인자이다. 본 연구에서는 서점의 성능위주 화재안전설계에 이용할 목적으로 적재가연물을 대상으로 연소발열성상을 측정하기 위한 화재실험을 행하였다. 실험에서는 서적과 서가의 일부분을 재현한 시험체를 내화로에 넣고 ISO834 표준가열곡선에 따라 가열하여 화재 최성기에서의 연소성상을 파악하였다. 그 결과, 서적은 외부 가열을 받으면 표면연소 후에 탄화하여 주위에 고온이 형성되어도 열분해가스의 방출량이 증가하지 않는 것으로 파악되었다.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.649-655
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• 2009

Traffic safety and vibration serviceability of a railway bridge set a limitation to the application of long-span cable supported bridges even though the design trend of the bridge becomes longer and lighter. In the case of high speed railway, it becomes more severe for the high speed of the train and resonance of the structure. Therefore, the cable supported bridge does not exist in Korea high speed railway until now. On the other hand, in recent, Italia, Japan and China do design and construct the long-span cable supported bridges for high speed railway recently with overcoming of traffic safety and passenger comforts. In the present study, prior to analysis of traffic safety and passenger comforts, a extradosed bridge for common railway is re-designed for high speed railway. The difference of member forces and displacements by design live load, the difference of impact coefficient and variable stresses of cables are investigated.

• Journal of the Korean Professional Engineers Association
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• v.36 no.1
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• pp.31-34
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• 2003

We have made an effort to build an affluent society since the industrial revolution. But we have just realized that the effort is also spoiling ourselves. Because our wealth has been acquired at the sacrifice of the environment only in which we can live. The amount of carbon dioxide emitted by burning fossil fuels is representing the environment disruption problems. Fortunately our mind ts changing. Many trials are being paid against the increase of carbon dioxide to save our environment. The roll of consulting engineers is to make a keen effort tn each professional field and to appeal the importance of mindtng the environment by giving a clear image of the problems to the public. The aim of the technical development should not be at the convenience of our lives but should be at the decrease of environmental load. That Is a new utopia of technology.nology.