• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.402-412
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• 2017

The convergence of broadcasting and telecommunication technologies is a key issue of the ubiquitous networks. So this paper offers the convergence of integrated telecommunication networks and broadcasting system, Advanced Terrestrial Digital Multimedia Broadcasting (AT-DMB), and the interconnection of them via the Media Independent Information Server/Service (MIIS). Then, this paper proposes the fast wakeup and connection mechanism with concepts for improving QoS and energy efficiency simultaneously. In the proposed convergence network, our mechanism places the key on the minimization of both the incoming service delay destined to a turned-off interface by using the broadcasting network and the additional energy consumption. This paper further evaluates the performance of proposed mechanism through the numerical and experimental analysis and has confirmed the decrease of both service delay and energy consumption.

• Journal of KIBIM
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• v.1 no.2
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• pp.12-18
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• 2011

The BIM techniques which manages information over the life cycle of construction project based on the 3-dimensional model are developing in the direction of integrated construction management including planning, design, analysis, estimation, 3D simulation and so on. The estimation model based on the BIM has different detail level and model information. In this study, the LOD of estimation model is catched for the bridge structures. The library classes are defined with construction information classification system, and the quantities of resources are calculated by class parameter using Microstation API. Finally, the automated estimation system using BIM based library is verified by the integrated model for adjustments of level of detail.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.161-168
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• 2016

CNG engine has been used as a transportation because of higher thermal efficiency and lower CO2 and particulate matter. However its out put power is decreased due to cylinder-to-cylinder variation during the supply of air-fuel mixture to the each cylinder. It also causes noise and vibration. So in this study, 1D engine simulation model was validated by comparison with experiment data and 3D CFD simulation was conducted to steady-state flow analysis about each manifold geometry. Then, the effects of various intake manifold geometries on variation were evaluated by using 1D-3D coupling analysis at engine speed of 2100 rpm range in 12 L CNG engine. As a result, variation was improved about 4 % though 3D CFD analysis and there was a variation within 3 % using 1D-3D coupling analysis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.284-290
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• 2013

The authors propose a nonlinear unknown input observer to estimate the angular speed of a satellite and to detect faults of reaction wheels. Input values are necessary to estimate the angular speed. Therefore, estimation errors are inevitable if faults occur in actuators or reaction wheels. Unknown input observers are useful to estimate the states of a system without being affected by unknown faults. The authors have designed a nonlinear unknown input observer by using the SDRE method and verified the proposed observer via numerical simulations. In spite of various and simultaneous faults, we have estimated the states and detected faults exactly by the proposed nonlinear unknown input observer.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.749-752
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• 2003

The HLA is defined by three components: (1) Rules, (2) the HLA Interface Specification, and (3) the Object Model Template(OMT). The RTI(Run-Time Infrastructure) software implements the interface specification. It provides services in a manner that is comparable to the way a distributed operating system provides services to applications. A way to test whether is suitable for a standard, and all service was implemented is tested through two phases of processes to verify the RTI which proposed in DMSO. In this paper, we discuss Level One Test Procedures and a method. Confirms whether RTI was implemented in Interface Specification according to Level One Test Procedures appropriately through a test. Develops Test Suite for every each step to test whether a correct command and the expected results are occur.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.355-362
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• 2013

A hardware implementation of phase calculator for extracting 3D depth image from TOF(Time-Of-Flight) sensor is described. The designed phase calculator, which adopts a pipelined architecture to improve throughput, performs arctangent operation using vectoring mode of CORDIC algorithm. Fixed-point MATLAB modeling and simulations are carried out to determine the optimized bit-widths and number of iteration. The designed phase calculator is verified by FPGA-in-the-loop verification using MATLAB/Simulink, and synthesized with a TSMC 0.18-${\mu}m$ CMOS cell library. It has 16,000 gates and the estimated throughput is about 9.6 Gbps at 200Mhz@1.8V.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.104-109
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• 2007

최근 분산된 자원을 효과적으로 공유할 수 있는 그리드 기반의 과학 연구가 다양하게 진행되고 있으며, 그러한 예로 국내에서는 건설 및 토목 분야의 원격실험 관측과 제어를 포함한 공동연구 환경의 구축을 내용으로 하는 KOCED(Korea Construction Engineering Development) 프로젝트가 진행 중에 있다. 본 논문에서는 KOCED에서 구축 중인 실험센터의 하나로써, 지리적으로 떨어진 실험 시설과 수치시뮬레이션을 연동하여 실험할 수 있는 하이브리드 실험센터를 대상으로 데이터 모델링을 하였다. 데이터 모델은 데이터를 표현하는 용어를 통일하고 데이터 간의 관계를 명확하게 하여, 데이터의 재사용성을 높일 수 있기 때문에 실험비용이 많이 소모되는 과학실험에 필수적이다. 그리드에 기반한 하이브리드 실험의 데이터 모델링은, 기존의 건설 및 토목실험의 대부분이 독립적인 실험 형태였기 때문에, 정확한 데이터 모델을 예측하기가 용이하지 않았다. 따라서 먼저 하이브리드 실험의 축소 모형인, 프로토타입 실험체를 만들고, 이에 대한 데이터 모델을 설계하여 토목공학 연구자에 의해 사용하게 하였다. 일정기간 사용기간을 갖고, 이에 대한 회의를 통해 향후 구축될 하이브리드 실험센터의 데이터 모델을 설계하였다. 현재 하이브리드 실험의 데이터 모델을 그리드 포탈 기반의 데이터관리 서비스로 구현 중에 있다.

• Journal of the Korea Computer Industry Society
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• v.4 no.12
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• pp.873-886
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• 2003

Lookup Is one of important factors for network traffic on peer-to-peer network. Especially, large amount of network resources are required for lookup process in p2p file sharing system that clients use the dynamic If and they import to p2p network in random. In this paper, we employ efficient lookup mechanism which searches lookup with the combined information of ISP key values and the extracted key values from SHA-1 hashing function for shared contents id. The proposed mechanism efficiently searches files on the network because the mechanism processes P2P lookup with consideration the routing information of ISP. We suggest the adapted simulation environment based upon the famous file sharing system of emule P2P and experiment the proposed system.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.138-144
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• 2017

A method for improving the integrated navigation performance in the INS/GPS navigation system by the considering that the condition that the geometric arrangement of the satellite is degraded due to limitation of the line of sight of the satellite such as geographic feature and GPS signal jamming is proposed. A variable covariance extended Kalman filter (VCEKF) that correlated to the measured covariance to the DOP of GPS is suggested. The navigation performance of integrated navigation system using EKF and VCEKF is analyzed by Monte-Carlo simulations. The result is verified that VCEKF has better estimation performance than EKF using fixed covariance on condition that DOP value is larger than the smaller value.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.586-592
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• 2012

One approach of the control of a nonlinear system that has gained some success employs a fuzzy structure in cooperation with a neural network(ANFIS). The traditional ANFIS can only model and control the process in single-dimensional output nature in spite of multi-dimensional input. The membership function parameters are tuned using a combination of least squares estimation and back-propagation algorithm. In the case of a mobile robot, we need to drive left and right wheel respectively. In this paper, we proposed the control system architecture for a mobile robotic system that employs the 2-input 2-output ANFIS controller for trajectory tracking. Simulation results and preliminary evaluation show that the proposed architecture is a feasible one for mobile robotic systems.