• International Journal of High-Rise Buildings
• /
• v.9 no.3
• /
• pp.301-306
• /
• 2020

In tall building construction, the appropriate control of lifting loads on tower cranes is critical in terms of the construction duration of structural works. The adoption of efficient construction methods can be the most effective way of minimizing the inputs of tower cranes and making a lifting plan and management easier. Based on actual data from a tall building project, this study comparatively analyzes lifting loads of tower cranes by the core structure preceding construction method (CSPCM) and the core structure succeeding construction method (CSSCM). The results revealed that the CSSCM could reduce up to about 56.3% of lifting loads for core works and significantly enhance lifting efficiency compared with the CSPCM. Consequently, this enabled a substantial reduction in the construction duration of structural works. This study provides a practical reference to assist engineers and managers in applying efficient construction methods and lifting equipment operation in tall building projects.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.34 no.4 s.117
• /
• pp.18-36
• /
• 2006

The purpose of this research was to establish a green-networks from the perfective of landscape ecology in order to improve the function of urban green spaces. The study site was Dalsu-Gu in Daegu City. This research consisted of three phases. In the first phase, field surveys were carried out in order to understand existing distribution pattern of green spaces in the study site. 533 green spaces surveyed in the first phase were classified into 7 patterns and 24 types. The total area of the green spaces in Dalsu-gu was 3,329ha. Specifically the area of the 'urban nature parks' type was 57.49% of the total area of green spaces in Dalsu-gu, and it was expected that 'urban nature parks' type can play important roles in the green-networks in Dalsu-gu. Two analysis with green spaces in 9 types including 'urban nature parks', 'rivers' and 'neighborhood parks' were performed to establish a basic network frame of the green-networks. In the second phase, 'mutual connectivity analysis' and 'mutual matrix analysis' were performed to select core green spaces of a green-networks using 'areas of each green space and a distance between each space' and 'a rate of green spaces and a rate of water permeable pavement'. The results of the second phase indicated that, in mutual connectivity analysis, large green spaces apart from each other were evaluated as having higher mutual connectivity than small green spaces near to each other. In mutual matrix analysis, the green spaces with higher mutual connectivity and the small green spaces near to each other were evaluated as having better mutual matrix. In the last phase, we structured a basic frame of the green-networks in Dalsu-Gu. The results suggested that the basic frame of the green-networks in Dalsu-Gu was composed on four green-network axes and its shape mirrored a cruciform(+) of northwest${\longleftrightarrow}$southeast directions and southwest${\longleftrightarrow}$northeast directions, The Duryu neighborhood park is at the central point of this green-networks.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.4
• /
• pp.655-661
• /
• 2020

In this study, the correlation between concrete core compressive strength and rebound hardness of urban railway underground structures was analyzed. The equations for the range of rebound hardness were derived and compared with the measured concrete core strengths for each range of rebound hardness to confirm the adequacy of the estimated compressive strength. As the result, the linear regression analysis results of the average compressive strength by the Gaussian probability density function (representative compressive strength estimation formula) and the estimation formula by the rebound hardness range were founded to match well within 3% of the experimental concrete core compressive strength test results. Therefore, the stochastic statistical analysis using the rebound hardness measurement results suggested in this study could be help to secure the confidence level of the correlation between the rebound hardness and the concrete compressive strength which are relatively large deviation according to the estimation equations.

• Journal of the Economic Geographical Society of Korea
• /
• v.9 no.2
• /
• pp.261-272
• /
• 2006

This work examines the delimitation of metropolitan areas in Canada, focusing on the Census Metropolitan Areas/Census Agglomerations(CMAs/CAs) that the Statistics Canada defines every Census year. The CMA/CA is built upon the functional-area method which is among the three approaches (i.e., density-based, land use-based, functional-area approaches) to the definition of an urban area. Importantly, the delimitation of a CMA/CA employs the Urban Area(UA) which the Statistics Canada defines via density-based and land use-based methods. In particular, the UA which has 10,000 or more residents is the urban core of a CMA/CA. Our examination of the CMA/CA in Canada also presents some points to be considered with regard to the delimitation of metropolitan areas in Korea which has yet to be implemented.

• International Journal of High-Rise Buildings
• /
• v.6 no.1
• /
• pp.1-9
• /
• 2017

The Pertamina Energy Tower (PET) and Manhattan West North Tower (MWNT) are two supertall towers recently designed and engineered by Skidmore, Owings & Merrill (SOM). The structural system for both buildings consists of an interior reinforced concrete core and a perimeter moment frame system, which is primarily structural steel. As is typical for tall towers with both concrete and steel elements, staged construction analysis was performed in order to account for the long term effects of creep and shrinkage, which result in differential shortening between the interior concrete core and steel perimeter frame. The particular design of each tower represents two extremes of behavior; PET has a robust connection between the perimeter and core in the form of three sets of outriggers, while the perimeter columns of MWNT do not reach the ground, but are transferred to the core above the base. This paper will present a comparison of the techniques used during the analysis and construction stages of the design process with the goal of understanding the differences in structural behavior of these two building systems in response to the long term effects of creep and shrinkage. This paper will also discuss the design and construction techniques implemented in order to minimize the differential shortening between the interior and exterior over the lifespan of these towers.

• Journal of Positioning, Navigation, and Timing
• /
• v.10 no.4
• /
• pp.235-242
• /
• 2021

Unmanned Aerial Vehicles (UAVs), which were used for military purposes, are gradually expanding their application fields under the influence of electrification and digitalization. Starting from the field of aerial imaging and Intelligence Surveillance and Reconnaissance (ISR) mission, nowadays the possibility of Urban Air Mobility (UAM), which transports passengers and cargo with drones, is widely under discussion. In order to occupy the rapidly growing global unmanned aerial vehicle market in advance, it is necessary to secure core technologies and develop key UAVs components based on the new technologies. In the navigation field, it is necessary to secure a precise position with guaranteed reliability and continuity, unrelated to the operating environments. The reliability and continuity should be secured in the algorithm level and in the H/W component levels also. In order to achieve this technical goal, the Ministry of Science and ICT has launched the 'Unmanned Vehicle Core Technology Research and Development Program' in 2019 to support the R&D on the unmanned vehicle technologies. In this paper, authors introduce the unmanned vehicle core technology research and development program to the related researchers. The authors summarize the backgrounds of the program and show the technological tasks and objectives on the sub-programs in the unmanned vehicle navigation program. We present the program schedules especially focused on the test and evaluation of the developed technologies and components.

• Korean Journal of Environment and Ecology
• /
• v.18 no.4
• /
• pp.359-368
• /
• 2004

The purpose of this study is to examine distribution and damages of the trails of inquiry of urban natural parks. Those parks were located at south-north green corridor at Incheon being mountainous type of urban natural parks that were core area of urban ecosystem preservation to of urban natural parks that citizens recently made use of them as nature experience type of leisure and recreation place from time to time, and to supply basic material deciding on the ways to improve the trails of nature preservation type. The survey sites included Geyang Park, Baekma Park, Yaksa Park, Munhak Park and Cheongryang Park. The number of main trails was 42 at Geyang Park, 43 at Baekma Park, 9 at Yaksa Park, 28 at Munhak Park, and 22 at Cheongryang Park, and it was excessively more than optimum needed: The number of branch trails of the parks seemed to increase. The bared trail width in average of the roads was 3.5m, while maximum depth in average was 21.3cm. The trails were thought to be deteriorated rapidly without systematic maintenance. The 5th and 6th grade of the impact rating class that required restoration because of serious deterioration occupied 19.6∼78.0%. Based on the findings, the study suggested ways to improve and manage the trails of inquiry of urban natural parks that were placed at south-north green corridor at Incheon.

• Journal of Environmental Impact Assessment
• /
• v.14 no.6
• /
• pp.403-413
• /
• 2005

The environmental conservation-targeted zoning in urban planning process has been functioned as securing a ecological core in urban green spaces management. Hence, the designation of conservation zones in land use planning is considered as a key task to achieve the sustainability of urban planning. The recently introduced pre-environmental review system for the proposed urban plan, by which the conservative measures for urban ecosystem and landscape are suggested in aspect of environmental impact mitigation, has played an active role in enhancing the environmental performance degraded by wide range of development pressure. This study is aimed at drawing out of objective criteria for designation of environmental conservation zones, which can be applied to urban planning establishment and also to environmental assessment process. To achieve this goal, the study adopted the following methods; pre-study review, analysis of existing official opinion statements released by the Ministry of Environment, contents analysis of related laws, and experts' panel discussions on the finally arranged criteria. The results of this research can be summarized as follows: First, the total criteria of 48 are drown out with categorizing into environment-ecological and socio-cultural sectosr. Second, the environment-ecological part is composed of 33 criteria such as vegetation, animal, geomorphology, watershed, environmental land suitability, and etc. Here, the Degree of Ecological Function, Degree of Environmental Land Suitability, and Vegetation Map are mainly utilized. Third, the 15 socio-cultural criteria relating to the history, social ecology and landscape have such components as forest around relics, Seo-won(school), castle, tomb, landmark, skyline, natural landscape, and etc. Forth, these individual criteria can be applied to designation of each conservation zones among total of 11 conservation areas(or districts).

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.4
• /
• pp.85-96
• /
• 2020

The honeybee serves for most entomophilous flowers. They are a core species for maintaining the ecological system. Though the urban ecological system needs bees' mediation of pollination as well, we have little understanding on how the honeybee reacts to the physical environments of an urban city. This study is a basic research to enhance the potential environment for pollination in an urban area and aims to review the urban environmental variables which are highly linked to the pollination mediations by the honeybee. The study composed a Maxent model by adopting nine urban environmental variables and the locations of the Apis mellifera's appearances around 52 spots in Seoul. The variables reflect the ecology of the Apis mellifera. Of the urban environmental variables used for the model composition, six variables were found as not having meaningful correlations with the Apis mellifera's appearances and finally, building coverage, actual vegetation and land cover were selected as the appearance variables of the Apis mellifera. The AUC, the reliability indicator of the final model was 0.791 (sd=0.077). And the importance data of the variables used for the model were 55.6%, 27.9%, and 16.5% for building coverage, actual vegetation and land cover, respectively. The result of the study showed that the building coverage has the highest correlation with the appearance of the honeybee. And, as per the actual vegetation, the artificially tree planted area as well as the cultivated field and meadow in an urban area were functioning as the most important environmental conditions for the honeybee to be inhabitable. The study is expected to be utilized as the base material for the urban planning and park green area planning to enhance the potential environment for pollination in an urban area.

• Journal of the Korean Regional Science Association
• /
• v.40 no.2
• /
• pp.57-73
• /
• 2024

The purpose of this study is to establish the central hierarchy and urban spatial structure of Daejeon in 2040 using differentiated analysis indicators. In order to establish a central hierarchy in the future urban space of Daejeon City, three indicators were derived: population density, use of buildings (commercial, office, residential, etc.) and traffic volume data(KTDB). The results of analyzing the center hierarchy using indicators are as follows. First, the primary centers responsible for urban (core) functions are set in three areas, including Dunsan downtown, the original downtown (Daejeon Station area, designated as a special urban convergence zone), and Doan New Town, and the secondary centers corresponding to sub-city centers (regional bases). was set at 9, 10 tertiary centers corresponding to regional centers (living area centers), and a center hierarchy was established with 5 new specialized bases. Second, new secondary and tertiary centers emerged that were different from the center hierarchy in the 2030 Daejeon Urban Basic Plan. The three indicators used in this study yielded meaningful results in establishing urban spatial structure and central hierarchy that can secure urban competitiveness.