• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.2
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• pp.166-180
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• 1998

In a city where the greenery always lacks landscaping roofs of existing buildings offers a way to solve the problem. But the most serious problem that poses is the matter of load limit. At present most existing buildings have the loading capacity of 200 kg/$m^2$ or less on their roofs. If the natural soil is used the loading capacity is easily surpassed because it simply is too heavy. To alleviate this problem it is realized to introduce the light weight artificial soil. The specific gravity of light soil is 0.65 whereas the natural soil is 1.8 when wet. It is three times lighter than the natural soil, thus eases the burden to the roof. The next problem to be confronted is the plant species to plant. It is possible to plant trees but they soon outgrow the loading capacity by weighing 8 times heavier in 10 years. Therefore shrubs and perennials are suggested to be planted because they don't weigh much even when they reach the mature height. The last problem is the stress put on roofs by the weight of the users. By some unexpected event the crowd gathered on a weak roof can cause the structural damage or even the collapse of the roof. The avoid the possibility of collapse a plaza or big pocket should not be designed in a roof garden because they hold crowd. By following the suggested means the old roofs of existing buildings can turn into the urban oases in the sky.

• Journal of the Korea Society of Computer and Information
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• v.21 no.9
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• pp.79-84
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• 2016

In this paper we consider the problem of finding the triplet (S,${\pi}$,f), where $S{\subseteq}V$, ${\pi}$ is a sequence of nodes in S and $f:V{\backslash}S{\rightarrow}S$ for a given complete graph G=(V,E). In particular, there exist two costs, $c^V_{uv}$ and $c^D_{uv}$ for $(u,v){\in}E$, and the cost of triplet (S,${\pi}$,f) is defined as $\sum_{i=1}^{{\mid}S{\mid}}c^V_{{\pi}(i){\pi}(i+1)}+2$ ${\sum_{u{\in}V{\backslash}S}c^D_{uf(u)}$. This problem is motivated by the integrated routing of the vehicle and drone for urban delivery services. Since a well-known NP-complete TSP (Traveling Salesman Problem) is a special case of our problem, we cannot expect to have any polynomial-time algorithm unless P=NP. Furthermore, for practical purposes, we may not rely on time-exhaustive enumeration method such as branch-and-bound and branch-and-cut. This paper suggests the simple heuristic which is motivated by the MST (minimum spanning tree)-based approximation algorithm and neighborhood search heuristic for TSP.

• Journal of Navigation and Port Research
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• v.29 no.3 s.99
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• pp.221-226
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• 2005

This paper provides a method to implement IT system for supply chain management problem The fundamental scheduling issues that arise in the pickup delivery system are optimizing the system with the minimum cost, the maximum throughput and the service level. This study is concerned with the development of the customer responsive pickup-delivery system based on e-logistics and demand chain management. Through this study, the pickup-delivery problem of the vehicle using the GIS PDP and GUI- type computer programs are formulated. The computational results show that the proposed method is very effective on a set of test problems.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.89-100
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• 2008

In an urban network controlled by traffic signals, there is an interaction between the signal timing and the routes chosen by individual road users. This study develops a bi level programming model for traffic signal optimization in networks with path based traffic assignment. In the bi level programming model, genetic algorithm approach has been proposed to solve upper level problem for a signalized road network. Path based traffic assignment using column generation technique which is proposed by M.H. Xu, is applied at the lower-level. Genetic Algorithm provieds a feasible set of signal timings within specified lower and upper bounds signal timing variables and feeds into lower level problem. The performance of this model is investigated in numerical experiment in a sample network. In result, optimal signal settings and user equilibrium flows are made.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1739-1742
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• 2011

Public transportation network in our country is concentrated and advanced focusing on urban area in order to secure economic feasibility. As a result, as dependence on private vehicles is relatively getting higher in public transportation vulnerable area, traffic problem occurs since the average running speed in urban area is 22.5km/h. This paper has an objective to suggest an improvement plan by selecting public transportation vulnerable area, and defining according to urban structure, formation and function, and understand traffic characteristics and draw problems. As a method selecting public transportation vulnerable area, an area with high division rate of vehicle was selected as a primary proposed site by calculating division rate of means of public transportation according to area. Final proposed site was selected by using GIS Buffering technique aiming at selected proposed site, and selecting non-benefit area 500m outside, which is the road limit distance from each subway and bus station. Lastly, the degree of improvement effect was studied by constructing imaginary public transportation network aiming at final proposed site and comparing to the amount of change in division rate of means of transportation.

• KIEAE Journal
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• v.11 no.5
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• pp.3-12
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• 2011

Industrialization and development of technology satisfied various humanly needs and lay the basis of numerous benefit and profit. New technologies like these mostly required large amounts of fossil Fuel, Fossil energy depletion rate was increasing rapidly. However, technical development for Human race required absolute sacrifice of the environment. Especially, 'City' which had been focused as stage of human activities, allowed to continue to have fossil energy dependent activities, and it shows in many data that the city is responsible for the 75-80% of the green house gas by human. In order to solve the problem relating climate changes and energy, European countries already made progress studies on many of the low carbon green city and pilot case construction. Especially, Germany, Austria, Holland, Sweden who had been playing leader role on environmental awareness and ecological concept, are actively constructing low carbon green city project based on Ecological city planning scheme. These projects positively utilize planning scheme that limits carbon emission using Urban Metabolism concept. Therefore, throughout this study, I would like to present planning and direction of future domestic low carbon green city by analyzing theories relative theories and best practices in Europe.

• Journal of Environmental Impact Assessment
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• v.17 no.4
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• pp.213-224
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• 2008

Since 1970's rapid urbanization and economic growth, the population was highly increased and residential type was changed from single detached house to high density and high-rise apartment. Recently more high-rise residential building generates more traffic volumes and it makes spatial concentration. The highly traffic volumed road and high residential building was constructed nearby, it occurs noise problem. The purpose of this study is comparing the performance of three type noise barrier between noise source and receiver using a noise map simulation. Three types were composed as road side planting trees, building side planting trees and noise barrier wall. Planting trees is less effective than noise barrier wall as a noise barrier. And they are all effective under 3 stories than over 5 stories, especially noise barrier function can't work over 5 stories.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.374-377
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• 2005

Automobile is in charge of most transportation system in modern urban city. However, in fact, cause of problem of road state, environment, and the other reasons, urban transit system is using as Mass Transit nowadays. Nevertheless Urban transit system is considering many kind of safety fact of that system which is increasing continuously nowadays, it occurs various train accident. This paper describes 3D Dimensional Measurement(EDM testing) and tensile testing results of carbody structure for crashed EMU(Electric Multiple Units). Tensile tests were performed on two different types of specimens in order to evaluate the strength changes before and after damages, obtained from plastic deformed area and nondeformed region of the crashed EMU. And Structural analysis of EMU was performed for the criteria of safety assessment. Structural analysis using commercial I-DEAS software provided important information on the stress distribution and load transfer mechanisms as well as the amount of damages during rolling stock crash. The testing results have been used to provide the critical information for the criteria of safety diagnosis.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.803-817
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• 2017

Structural health monitoring has increasingly been a focus within the civil engineering research community over the last few decades. With increasing application of sensor networks in large structures and infrastructure systems, effective use and development of robust algorithms to analyze large volumes of data and to extract the desired features has become a challenging problem. In this paper, we grasp some precautions and key points of the signal processing approach, wavelet, establish a relative reliable framework, and analyze three problems that require attention when applying wavelet based damage detection approach. The cases studies how to use optimal scales for extracting mode shapes and modal curvatures in a reinforced concrete beam and how to effectively identify damages using maximum curves of wavelet coefficient differences. Moreover, how to make a recognition based on the wavelet multi-resolution analysis, wavelet packet energy, and fuzzy sets is a meaningful topic that has been addressed in this work. The relative systematic work that compasses algorithms, structures and evaluation paves a way to a framework regarding effective structural health monitoring, orientation, decision and action.

• The Journal of Korea Robotics Society
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• v.10 no.1
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• pp.33-41
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• 2015

Recent developments in robotics and intelligent vehicle area, bring interests of people in an autonomous driving ability and advanced driving assistance system. Especially fully automatic parking ability is one of the key issues of intelligent vehicles, and accurate parked vehicles detection is essential for this issue. In previous researches, many types of sensors are used for detecting vehicles, 2D LiDAR is popular since it offers accurate range information without preprocessing. The L shape feature is most popular 2D feature for vehicle detection, however it has an ambiguity on different objects such as building, bushes and this occurs misdetection problem. Therefore we propose the accurate vehicle detection method by using a 3D complete vehicle model in 3D point clouds acquired from front inclined 2D LiDAR. The proposed method is decomposed into two steps: vehicle candidate extraction, vehicle detection. By combination of L shape feature and point clouds segmentation, we extract the objects which are highly related to vehicles and apply 3D model to detect vehicles accurately. The method guarantees high detection performance and gives plentiful information for autonomous parking. To evaluate the method, we use various parking situation in complex urban scene data. Experimental results shows the qualitative and quantitative performance efficiently.