• Advances in Computational Design
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• v.3 no.2
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• pp.201-212
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• 2018

Decrease in availability of suitable subbase and base course materials for highway construction leads to a search for economic method of converting locally available troublesome soil to suitable one for highway construction. Present study insights on evaluation of benefits of stabilization of subgrade soils in term of extension in service life (TBR) and layer thickness reduction (LTR). Laboratory investigation consisting of Atterberg limit, Compaction, California Bearing Ratio, unconfined compressive strength and triaxial shear strength tests were carried out on two types of soil for varying percentages of stabilizers. Vertical compressive strains at the top of unstabilized and stabilized subgrade soils were found out by elastoplastic finite element analysis using commercial software ANSYS. The values of vertical compressive strains at the top of unstabilized and stabilized subgrade, were further used to estimate layer thickness reduction or extension in service life of the pavement due to stabilization. Finite element modeling of the flexible pavement layered structure provides modern technology and sophisticated characterization of materials that can be accommodated in the analysis and enhances the reliability for the prediction of pavement response for improved design methodology. If the pavement section is kept same for unstabilized and stabilized subgrade soils, pavement resting on lime, fly ash and fiber stabilized subgrade soil B will have service life 2.84, 1.84 and 1.67 times than that of unstabilized pavement respectively. The flexible pavement resting on stabilized subgrade is beneficial in reducing the construction material. Actual savings would depend on the option exercised by the designer for reducing the thickness of an individual layer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.595-601
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• 2015

These days, research related to Intelligent Transportation System (ITS) technology is being widely considered. ITS is inevitable for future transportation systems to reduce accidents, congestion, and offer a smooth flow of traffic. The use of Visible Light Communication (VLC) in ITS systems has been considered widely because of its EMC/EMI free and LED infrastructure reusable properties. Among the VLC schemes, this study analyzed the performance of the Color Shift Keying (CSK) scheme under a Vehicle-to-Infrastructure (V2I) downlink scenario to verify the capability of CSK as a communication tool for ITS. By modeling daylight noise using the modified Blackbody radiation model, this study examined the performance of V2I VLC under daytime conditions. The relationship between BER, the communication distance, and the amount of ambient-light noises under the pre-described V2I scenario were determined by simulations.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.289-300
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• 2005

This paper proposed an analytical framework to compare and model the policy-based network management; centralized and distributed typed model. Policy-based network is introduced in various application fields, and a policy framework can offer different processing performance according to application. Therefore, we evaluated the performance and extensibility of each PBNM model when we apply the policy process to the models. The evaluated measurement metrics are policy provisioning time, traffic occurrence amount, PDP processing rate, and global conflict detection in qualitative simulation. The results show that the suitable structure is required according to the analysis for the careful application characteristics, when PBNM is adopted. The modeling framework presented in this paper is intended to quantify the merits and demerits among the currently suggested PBNM models.

• International Journal of Highway Engineering
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• v.4 no.4 s.14
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• pp.1-12
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• 2002

Pavement Management System has a special purpose that the rehabilitation strategy applied on pavement should be executable in view of technical and economical point after new pavement open to the traffic. To achieve that purpose, a reliable pavement performance prediction model should be embeded in the system. The object of this study is to develop a probabilistic pavement performance prediction model for evaluating asphalt pavements based on the Markov chain concept. In this paper, methodology of the Markov chain modeling principle is explained, and the application of this model to asphalt pavement is described. As the results, transition matrics for predicting asphalt pavement performance are obtained, and also performance life is estimated quantitatively by this system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.9
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• pp.2982-3003
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• 2014

With the explosive deployment of the wireless communications technology, the increased QoS requirement has sparked keen interest in network planning and optimization. As the major players in wireless network optimization, the BS's resource utilization and mobile user's QoS can be improved a lot by the load-balancing technology. In this paper, we propose a load-balancing strategy that uses Coordinated Multiple Points (CoMP) technology among the Base Stations (BS) to effectively extend network coverage and increase edge users signal quality. To use universally, different patterns of load-balancing based on CoMP are modeled and discussed. We define two QoS metrics to be guaranteed during CoMP load balancing: call blocking rate and efficient throughput. The closed-form expressions for these two QoS metrics are derived. The load-balancing capacity and QoS performances with different CoMP patterns are evaluated and analyzed in low-dense and high-dense traffic system. The numerical results present the reasonable CoMP load balancing pattern choice with guaranteed QoS in each system.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.3
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• pp.387-391
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• 2008

For the detection of moving objects, background subtraction methods are widely used. In case the background has variation, we need to update the background in real-time for the reliable detection of foreground objects. Gaussian mixture model (GMM) combined with probabilistic learning is one of the most popular methods for the real-time update of the background. However, it does not work well in the complex and dynamic backgrounds with high traffic regions. In this paper, we propose a new method for modelling and updating more reliably the complex and dynamic backgrounds based on the probabilistic learning and the layered processing.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.65-74
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• 2019

3D file formats typically include OBJ (Wavefront file format), STL (STereoLithography), and FBX (Filmbox). Each format has limitations depending on its configuration and usage, and supported formats are different depending on the software application. glTF helps uniform integration of 3D file formats and allows for more efficient transmission of large 3D geometry files by organizing them in a binary format. This paper presents explanation on OBJ, FBX, and STL which are major examples of existing 3D file formats. It also explains the concept and characteristics of glTF and compares its performance with other 3D file formats on the web. The loading time and packets of each 3D file format are measured according to the web browser environment by means of Google Chrome, Firefox and Microsoft Edge. Experimental results show that glTF is the most efficient and that it exhibits the best performance. As to STL, relatively excessive traffic was observed. This study is expected to contribute to reducing rendering time on the web as 3D file formats are used.

• Structural Engineering and Mechanics
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• v.71 no.2
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• pp.131-138
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• 2019

It is necessary to predict subway induced vibration if a new subway is to be built. To obtain the vibration response reliably, a three-dimensional (3D) FEM model, consisting of the tunnel, the soil, the subway load and the building above, is established in MIDAS GTS NX. For this study, it is a six-story frame structure built above line 3 of Guangzhou metro. The entire modeling process is described in detail, including the simplification of the carriage load and the determination of model parameters. Vibration measurements have been performed on the site of the building and the model is verified with the collected data. The predicted and measured vibration response are used together to assess vibration level due to the subway traffic in the building. The No.1 building can meet work and residence comfort requirement. This study demonstrates the applicability of the numerical train-tunnel-soil-structure model for the serviceability assessment of subway induced vibration and aims to provide practical references for engineering applications.

• Wind and Structures
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• v.28 no.4
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• pp.225-238
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• 2019

In this paper a novel and efficient computational framework to estimate the stress range versus number of cycles curves experienced by a cable due to external excitations (e.g., seismic excitations, traffic and wind-induced vibrations, among others) is proposed. This study is limited to the wind-cable interaction governed by the Vortex Shedding mechanism which mainly rules cables vibrations at low amplitudes that may lead to their failure due to bending fatigue damage. The algorithm relies on a stochastic approach to account for the uncertainties in the cable properties, initial conditions, damping, and wind excitation which are the variables that govern the wind-induced vibration phenomena in cables. These uncertainties are propagated adopting Monte Carlo simulations and the concept of importance sampling, which is used to reduce significantly the computational costs when new scenarios with different probabilistic models for the uncertainties are evaluated. A high fidelity cable model is also proposed, capturing the effect of its internal wires distribution and helix angles on the cables stress. Simulation results on a 15 mm diameter high-strength steel strand reveal that not accounting for the initial conditions uncertainties or using a coarse wind speed discretization lead to an underestimation of the stress range experienced by the cable. In addition, parametric studies illustrate the computational efficiency of the algorithm at estimating new scenarios with new probabilistic models, running 3000 times faster than the base case.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.4
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• pp.95-105
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• 2000

The Firewall is needed in order to protect communication networks from ill effects of informatization such as information leakage, destruction, forgery and virus. To take an advantage of the firewall, the security manager must understand the effects that it can have on the network. There airs, however, no tools available to evaluate the performance of the firewall. In this paper, we study the effect of the firewall by putting various kinds of traffic into the actual network. Also, using COMNET- III, we model two networks with and without the firewall. And we analyze the effects under the various network envion-ments.