• Steel and Composite Structures
• /
• v.34 no.6
• /
• pp.837-851
• /
• 2020

This study aims to examine the interface shear behavior between precast high-strength concrete slabs with pockets and steel beam to achieve accelerated bridge construction (ABC). Twenty-six push-out specimens, with different stud height, stud diameter, stud arrangement, deck thickness, the infilling concrete strength in shear pocket (different types of concrete), steel fiber volume of the infilling concrete in shear pocket concrete and casting method, were tested in this investigation. Based on the experimental results, this study suggests that the larger stud diameter and higher strength concrete promoted the shear capacity and stiffness but with the losing of ductility. The addition of steel fiber in pocket concrete would promote the ductility effectively, but without apparent improvement of bearing capacity or even declining the initial stiffness of specimens. It can also be confirmed that the precast steel-concrete composite structure can be adopted in practice engineering, with an acceptable ductility (6.74 mm) and minor decline of stiffness (4.93%) and shear capacity (0.98%). Due to the inapplicability of current design provision, a more accurate model was proposed, which can be used for predicting the interface shear capacity well for specimens with wide ranges of the stud diameters (from13 mm to 30 mm) and the concrete strength (from 26 MPa to 200 MPa).

• Journal of Engineering Education Research
• /
• v.18 no.1
• /
• pp.47-53
• /
• 2015

The aim of this paper is to explore the formation of the Seoul-focused network city for technological commercialization compared with Seoul as a mega city. The growth of Seoul and subsequently, the Seoul metropolitan region as a mega city and mega region has led the uneven regional development in Korea since the 1960s. To reduce a huge gap between the Seoul metropolitan and the non-metropolitan region, the concept of network city can be suggested in terms of the functional and spatial division of labor. More specifically, such division of labour throughout the formation of the Seoul-focused network city concentrates on technological commercialization which is deeply concerned with R&BD (research and business development). For this network city, there are 4 axes such as the axis of South-North Korean cooperation (the axis of R&BD for complex technologies), that of the expansion of a mega city (that of R&BD for green growth technology), that of the linkage of small and medium-sized cites (that of R&BD for life science and technology) and that of megalopolis (that of R&BD for basic technology) with regards to the axis of urban development and technological specialization. It shall be argued that the formation of Seoul-focused network city can be an alternative to the contemporary uneven regional development between the Seoul metropolitan and non-metropolitan region in Korea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2006.06b
• /
• pp.301-307
• /
• 2006

As container traffic in the world increases rapidly, size if containership is become bigger and bigger. With these trends, many studies have. been done on such big ships by consultant, naval architects, port designers, ship operators, economists etc,. with different points of view and results. But previous studies were concentrated on hardware and theoretical side. Therefore the objective of this paper is to analyze response and intention of ship's user such as shipping companies and forwarding companies about prospects of mega-ship size, preference of Mega ship, problem and handling time of Mega ship.

• ALGAE
• /
• v.38 no.4
• /
• pp.283-294
• /
• 2023

Previous research indicated that free-living sporangial filament keep hollow morph under high-culture density and form bipartite cells under low-culture density, while the following conchospore release was inhibited by high light. Here, we further explored the molecular bases of these affects caused by light and culture density using a transcriptome analysis. Many differentially expressed genes (DEGs) related to carbon dioxide concentration and fixation, photosynthesis, chlorophyll synthesis and nitrogen absorption were upregulated under high-light conditions compared with low-light conditions, indicating the molecular basis of rapid vegetative growth under the former. The stress response- and ion transport-related DEGs, as well as the gene encoding the vacuole formation-brefeldin A-inhibited guanine nucleotide exchange protein (BIG, py05721), were highly expressed under high-density conditions, indicating the molecular basis of the hollow morph of free-living sporangial filaments under high-culture density conditions. Additionally, the brefeldin A treatment indicated that the hollow morph was directly influenced by vacuole formation-related vesicle traffic. Others DEGs related to cell wall components, zinc-finger proteins, ASPO1527, cell cycle and cytoskeleton were highly expressed in the low density with low-light group, which might be related to the formation and release of conchospores. These results provide a deeper understanding of sporangial filaments in Neopyropia yezoensis and related species.

• Journal of Navigation and Port Research
• /
• v.29 no.7
• /
• pp.635-640
• /
• 2005

This paper aims to understand and analyze the mega-trends such as trends towards larger vessels due to an increasing trade volume, accordingly fewer port calls, strategic alliances and M&A Increasing degree of concentration through M&A activities in shipping industry results in a decreasing number of shipping finns with an increasing share in the world shipping capacity. But competition is strongly increasing on main trunk routes. Therefore, shipping concentration directly leads to further concentration of port traffic in fewer and larger ports with an increasing competition among neighboring ports.

• Journal of Korean Port Research
• /
• v.13 no.1
• /
• pp.11-26
• /
• 1999

The subject of port efficiency is one of the important issues facing port authorities and policy makers today. A number of studies have been undertaken which compare ports in terms of their efficiency. But any port comparison can only be valid and meaningful if a port’s efficiency is compared with a similar port. The main objective of this paper is to introduce a systematic approach to identifying similar ports based on the technique of principal component analysis and cluster analysis. And it seeks to identify the most important factors underlying the port classification. Lack of awareness of which factors differentiate ports has resulted in an unnecessary collection of data which are of limited use in port classification. This paper has identified five groupings of similar ports within which port comparision can be justifiably made. This approach can be used for any future port comparision.

• Architectural research
• /
• v.12 no.1
• /
• pp.57-64
• /
• 2010

In recent years, interests and studies on the urban regeneration projects have been increased and largely conducted. It is a part of the effort that solves some social and economical problems occurred by deteriorated buildings and degraded infrastructures through new urban regeneration projects or redevelopment projects. However, the urban regeneration projects show the characteristics that can not guarantee in the project performance because the projects have various and complex stakeholders related to these projects and are exposed to lots of risks due to its huge scale. This study proposed the risk performance index method to improve the efficiency of the overall performance measurement for a mega-project by extending from the traditional cost/schedule based performance measurement system. The risk performance index method proposed in this study has a similar system to the EVMS, and makes possible to perform a three dimensional integrated performance measurement in cost/schedule/risk through 18 different indexes that compose the risk performance index.

• International Journal of High-Rise Buildings
• /
• v.5 no.3
• /
• pp.221-232
• /
• 2016

With the booming of construction and property industries in China, the demand for high-rises and mega-scale buildings with more integrated building functions, open- and tailor-shaped outlooks, better connections to municipal infrastructures, and higher grades of building importance has been increasing in the past two decades. The seismic design and engineering of such modern mega-buildings face engineering challenges such as hazard mitigation of extreme actions and surroundings, integrated structural frameworks and building skins, complex connections, and overall construction efficiency. It is the work of a new generation of civil and structural engineers to enhance engineering efficiency and achieve overall engineering, environmental, and economical effectiveness for these high-rise projects. This paper elaborates the above topics through case studies on the design and construction of four such developments in China. Some rethinking is conducted on evolution in modern seismic engineering and design through innovation to achieve an acceptable level of overall sustainability and building effectiveness.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2007.09a
• /
• pp.55-77
• /
• 2007

Currently a large number of high rise building projects are under plan and a mega foundation system to support this high load with safety is requiring. The foundation of a highrise building is displaced by the building load, which influence the behavior of a super structure in reverse. In this aspect, the structural interaction analysis between a foundation and a super structure is necessary. In this study, the relationship of a superstructure of building and a foundation has been reviewed, considering the tendency of design from a capacity driven design to a performance design. Two different case studies have been introduced to help understand this relationship in more specific, the first case is the high rise building founded on a mat system on rock and the second is that on large diameter bored piles on soft ground condition.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2008.11a
• /
• pp.441-444
• /
• 2008

메가프로젝트(Mega-Project)는 다양한 유형의 시설군을 복합 개발하는 건설사업으로서 규모가 크고 복잡한 경우가 많기 때문에 종합적인 사업관리에 어려움이 따른다. 따라서 메가프로젝트는 기존의 단위프로젝트 수준이 아닌 프로그램 수준에서의 관리체계를 필요로 하며 그에 적합한 업무분류체계(WBS)를 구축해야 한다. 업무분류체계는 사업관리를 위한 전체적인 구조를 수립하는 기반으로서, 현재 프로그램 관리 수준의 업무분류체계의 기준이 갖추어지지 않은 상황이다. 이에 본 연구에서는 메가프로젝트를 위한 업무분류체계기준(WBS Basis)를 개발하여 메가프로젝트의 업무분류체계 구축을 지원하고자 한다. 메가프로젝트 생애주기에 포함되는 전체 시설군, 업무 및 용역, 기록문서, 정보 등을 대상으로 하였으며, 기존 사례분석과 관련 분류체계들을 바탕으로 초안을 작성하였다. 이후 현장시험을 통한 검증을 거쳐 최종 업무분류체계기준을 완성하였고 분류내용과 활용방안을 소개한다.