• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.5
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• pp.52-60
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• 2013

ITS technologies are in the research and development around the world as a solution for maximizing the efficiency of the existing road infrastructure, solving the complex traffic problems and providing the convenient driving services. The core of these ITS technologies is to provide the information for the requesting users in fast and accurate way from the server. In real driving conditions, there are many communication barriers around the vehicles and the base stations so that an accurate and robust handover technology is needed in order to ensure seamless ITS services. This paper introduced an WAVE handover algorithm implemented in a real communication device and five parameters mainly affecting the handover performance are evaluated. The handover performance is measured by changing the parameter values at a highway testbed. The test results show that the handover algorithm parameter values should be configured carefully to remove the handover ping-pong problems.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.1-7
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• 2004

We have developed a 24GHz side-looking vehicle detection radar. A 24GHz front-end module and a novel signal processing algorithm have been developed for speed measurement and size classification of vehicles in multiple lanes. The system has a fixed antenna and FMCW processing module. This paper presents the background theory of operation and shows some measured data using the algorithm. The data shows that measured velocity of the passing vehicle is within the accuracy of 95% in single lane and the velocity of the vehicles in two lanes is within the accuracy of 90% by using variable threshold estimation. The classification of vehicle size as small, medium and large has been measured with 89% accuracy.

• Steel and Composite Structures
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• v.7 no.6
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• pp.487-502
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• 2007

In recent decades there has been a trend towards improved mechanical characteristics of materials used in footbridge construction. It has enabled engineers to design lighter, slender and more aesthetic structures. As a result of these construction trends, many footbridges have become more susceptible to vibrations when subjected to dynamic loads. In addition to this, some inherit modelling uncertainties related to a lack of information on the as-built structure, such as boundary conditions, material properties, and the effects of non-structural elements make difficult to evaluate modal properties of footbridges, analytically. For these purposes, modal testing of footbridges is used to rectify these problems after construction. This paper describes an arch type steel footbridge, its analytical modelling, modal testing and finite element model calibration. A modern steel footbridge which has arch type structural system and located on the Karadeniz coast road in Trabzon, Turkey is selected as an application. An analytical modal analysis is performed on the developed 3D finite element model of footbridge to provide the analytical frequencies and mode shapes. The field ambient vibration tests on the footbridge deck under natural excitation such as human walking and traffic loads are conducted. The output-only modal parameter identification is carried out by using the peak picking of the average normalized power spectral densities in the frequency domain and stochastic subspace identification in the time domain, and dynamic characteristics such as natural frequencies mode shapes and damping ratios are determined. The finite element model of footbridge is calibrated to minimize the differences between analytically and experimentally estimated modal properties by changing some uncertain modelling parameters such as material properties. At the end of the study, maximum differences in the natural frequencies are reduced from 22% to only %5 and good agreement is found between analytical and experimental dynamic characteristics such as natural frequencies, mode shapes by model calibration.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5311-5317
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• 2015

Cigarette smoke derivatives like NNK (4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone) and NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butan-1-ol) are well-known carcinogens. We analyzed the interaction of enzymes involved in the NER (nucleotide excision repair) pathway with ligands (NNK and NNAL). Binding was characterized for the enzymes sharing equivalent or better interaction as compared to +Ve control. The highest obtained docking energy between NNK and enzymes RAD23A, CCNH, CDK7, and CETN2 were -7.13 kcal/mol, -7.27 kcal/mol, -8.05 kcal/mol and -7.58 kcal/mol respectively. Similarly the highest obtained docking energy between NNAL and enzymes RAD23A, CCNH, CDK7, and CETN2 were -7.46 kcal/mol, -7.94 kcal/mol, -7.83 kcal/mol and -7.67 kcal/mol respectively. In order to find out the effect of NNK and NNAL on enzymes involved in the NER pathway applying protein-protein interaction and protein-complex (i.e. enzymes docked with NNK/NNAL) interaction analysis. It was found that carcinogens are well capable to reduce the normal functioning of genes like RAD23A (HR23A), CCNH, CDK7 and CETN2. In silico analysis indicated loss of functions of these genes and their corresponding enzymes, which possibly might be a cause for alteration of DNA repair pathways leading to damage buildup and finally contributing to cancer formation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.167-174
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• 2015

Since about 70 percent of the territory is mountainous, more tunnels are constructed in Korea for maximizing the development efficiency. With the increasing number of tunnel construction, safe construction in tunnels has been emerged as the utmost important subject. Recently, the number of long tunnel construction is steeply increased because of the request for high speed and straight road. In this study, a safe tunneling method using numerical modeling of rock blocks in long tunnels is proposed, and then applied to the long tunnel based on real discontinuity information observed in situ. It is possible to detect key blocks all along the tunnel exactly by using the numerical analysis program developed for the safe tunneling method using numerical modeling of rock blocks. This computer simulation method with user-friendly interfaces can calculate not only the stability of rock blocks but also the design of supplementary supports.

• Journal of Cadastre & Land InformatiX
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• v.44 no.2
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• pp.103-112
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• 2014

The objective of this study is to suggest the possibility on land cover classification using hyperspectal imagery on area which includes lands and waters. After atmospheric correction as a preprocessing work was conducted on hyperspectral imagery acquired by airborne hyperspectral sensor CASI-1500, the effect of atmospheric correction to a few land cover class in before and after atmospheric correction was compared and analyzed. As the result of accuracy of land cover classification by highspectral imagery using reference data as airphoto and digital topographic map, maximum likelihood method represented overall accuracy as 67.0% and minimum distance method showed overall accuracy as 52.4%. Also product accuracy of land cover classification on road, dry field and green house, but that on river, forest, grassland showed low because the area of those was composed of complex object. Therefore, the study needs to select optimal band to classify specific object and to construct spectral library considering spectral characteristics of specific object.

• Journal of ILASS-Korea
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• v.20 no.1
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• pp.28-34
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• 2015

Recently, some researchers have been carried out risk assessment of vehicles exhaust on human health. Especially, some of VOCs which is non-controlled, was classified to hazardous pollutant, such as 1,3-Butadiene and BTEX(Benzene, Toluene, Ethylbenzene and Xylene). Therefore, the profile on non-controlled pollutant may be needed in the future, because it would be critical data or information to control them. Additionally, with increasing amount of motorcycle, the source profiling is essential for estimating emission factor and amount on motorcycle exhaust. For these, in this study, imported motorcycles (8 vehicles) were selected as a test model while considering the increasing ratio on sales volume between 2013 and 2014; it was also compared with domestic motorcycles on those. The experiment was conducted by driving mode, UDC and ECE+EUDC that made from EURO III. In addition, it was performed at cold start driving mode without effect by displacement, for evaluating only correlation of BTEX with HC. In order to apply the ratio (m,p-Xylene/o-Xylene) as a marker, the ratio was compared with those of tunnel, road side and residential area. As a result, it showed best correlation ($R^2=0.98$) among those. In the future, it has to be considered as a marker for effect evaluation to atmospheric environment by exhaust emission.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1143-1155
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• 1999

셀룰러 방식의 이동통신 시스템에서 전파의 유효신호 도달범위를 예측하기 위해서는 전파전파 모델을 이용한 예측기법이 주로 사용된다. 그러나, 전파과정에서 주변 지형지물에 의해 발생하는 전파손실은 매우 복잡한 비선형적인 특성을 가지며 수식으로는 정확한 표현이 불가능하다. 본 논문에서는 신경회로망의 함수 근사화 능력을 이용하여 전파손실 예측모델을 생성하는 방법을 제안한다. 즉, 전파손실을 송수신 안테나간의 거리, 송신안테나의 특성, 장애물 투과영향, 회절특성, 도로, 수면에 의한 영향 등과 같은 전파환경 변수들의 함수로 가정하고, 신경회로망 학습을 통하여 함수를 근사화한다. 전파환경 변수들이 신경회로망 입력으로 사용되기 위해서는 3차원 지형도와 벡터지도를 이용하여 전파의 반사, 회절, 산란 등의 물리적인 특성이 고려된 특징 추출을 통해 정량적인 수치들을 계산한다. 이와 같이 얻어진 훈련데이타를 이용한 신경회로망 학습을 통해 전파손실 모델을 완성한다. 이 모델을 이용하여 서울 도심 지역의 실제 서비스 환경에 대한 타 모델과의 비교실험결과를 통해 제안하는 모델의 우수성을 보인다.Abstract In cellular mobile communication systems, wave propagation models are used in most cases to predict cell coverage. The amount of propagation loss induced by the obstacles in the propagation path, however, is a highly non-linear function, which cannot be easily represented mathematically. In this paper, we introduce the method of producing propagation loss prediction models by function approximation using neural networks. In this method, we assume the propagation loss is a function of the relevant parameters such as the distance from the base station antenna, the specification of the transmitter antenna, obstacle profile, diffraction effect, road, and water effect. The values of these parameters are produced from the field measurement data, 3D digital terrain maps, and vector maps as its inputs by a feature extraction process, which takes into account the physical characteristics of electromagnetic waves such as reflection, diffraction and scattering. The values produced are used as the input to the neural network, which are then trained to become the propagation loss prediction model. In the experimental study, we obtain a considerable amount of improvement over COST-231 model in the prediction accuracy using this model.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.11
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• pp.634-639
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• 2002

A Shortest Path Algorithm is the method to find the most efficient route among many routes from a start node to an end node. It is based on Labeling methods. In Labeling methods, there are Label-Setting method and Label-Correcting method. Label-Setting method is known as the fastest one among One-to-One shortest path algorithms. But Benjamin[1,2] shows Label-Correcting method is faster than Label-Setting method by the experiments using large road data. Since Graph Growth algorithm which is based on Label-Correcting method is made to find One-to-All shortest path, it is not suitable to find One-to-One shortest path. In this paper, we propose a new One-to-One shortest path algorithm. We show that our algorithm is faster than Graph Growth algorithm by extensive experiments.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.698-701
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• 2010

Recently, Vehicular Networks is being developed to provide variety of services such as email, ftp, and video streaming services. As IP mobility technology, Proxy Mobile IP is developed to provide these services for a VANET user. By adopting Proxy Mobile IPv6 (PMIPv6), Vehicular Networks can support IP mobility, but it may cause a proxy binding update (PBU) message when a vehicle moves from one MAG to another. In addition, if the density of vehicles on the road is high, significant PBU messages are generated. In this paper, we propose bulk PBU message to reduce signaling overhead by those PBU messages when a bunch of vehicles move from one MAG to another. When the vehicles move from one MAG to another, it generates only one bulk PBU message to update those vehicle's location. Through numerical and simulation results, we show that our proposed bulk registration reduces signaling overhead when the density of vehicles and the speed of them are high.