• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1092-1099
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• 2006

Displayed system equationally using accurate dynamic modeling of whole system including induction motor and load to analyze induction motor to normal condiction's action characteristic as well as transient characteristic using power converter device such as inverter in this paper. Also, presume adhesive power calculation through speed sensorless vector control and load torque disturbance observer for maximum tractive force control. Confirmed proposed algorithm through simulation and an experiment using railroad experiment equipment to embody control algorithm of such system. With relation of adhesive power about the wage speed by speed addition and subtraction of railway vehicle, embodied all sorts item by experiment equipment.

• International Journal of Highway Engineering
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• v.2 no.1
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• pp.135-145
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• 2000

A new procedure needs to be developed to predict the dynamic layer properties under moving truck loads. In this study, a computer code to evaluate layer moduli of asphalt concrete pavement from measured interior deflections at various depths were developed and verified from numerical model tests. Interior deflections of the pavement are measured from Multi-Depth Deflectometer(MDD). It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.32% for several numerical models tested. When impact loads were used, a technique to determine the depth to virtual rigid base was proposed through the analysis of compressive wave velocity and impulse loading durations. It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.114% when virtual rigid base was considered in numerical analysis. The pavement behavior must be evaluated under various vehicle speeds when determining the dynamic interaction between the loading vehicle and pavement system. To evaluate the dynamic behavior on asphalt concrete pavement under various vehicle speeds, truck moving tests were carried out. From the test results with respect to vehicle speed, it was found that the vehicle speed had significant effect on actual response of the pavement system. The lower vehicle speed generates the higher interior deflections, and the lower dynamic modulus.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.359-360
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• 2013

본 연구에서는 외부 자극과 내적인 교감신경의 변화에 따라 나타나는 땀 반응으로 얻어진 생체신호를 다루었다. 즉, 땀 반응을 지칭하는 피부전도도를 측정할 수 있는 시스템과, 더불어 차량 운전시 혹은 운동 등의 동적 자극에 의한 영향을 최소화하여 교감신경에 의한 피부전도도의 신뢰도를 높일 수 있는 방안을 강구하였다. 기존의 두 개의 전극 간 리지스턴스(Resistance)를 측정하는 방식을 내부에서 분리된 한 개의 전극을 사용하여 신체적 움직임의 제한점을 해소하고 피부전도도로 나타난 생체신호가 외적인 움직임에 따른 영향인지 내적인 신경의 변화에 따른 영향인지를 추정할 수 있는 모듈을 개발하였다. 20명의 건강한 청년을 대상으로 피실험하여 기존의 생체신호 측정 장비인 MP-150의 EDA모듈과 동시 측정한 결과, 두 데이터가 약 88% 일치하는 것으로 확인하였다.

• Journal of the Korea Convergence Society
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• v.8 no.5
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• pp.155-160
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• 2017

A cabin of the agricultural tractor is designed to protect the driver from vibration transmitted due to the irregular ground and overturning of the tractor. The cabin is usually manufactured by welding frames and plates. Consequently, the welded state of the frame and plate affects the stiffness of the cabin structure. In this paper, the static and dynamic stiffness characteristics of the cabin are identified through finite element analysis and effects of the structure production error are investigated to insure the structural stiffness of the cabin.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.2 s.3
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• pp.43-54
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• 2003

As the demand for ubiquitous mobile wireless Internet grows, vehicles are receiving a lot of attention as new networking platforms. The demand for 4G all-IP networks encourages vehicle networks to be connected using IPv6. By means of network mobility (NEMO) support, we can connect sensors, controllers, local ,servers as well as passengers' devices of a vehicle to the Internet through a mobile router. The mobile router provides the connectivity to the Internet and mobility transparency for the rest of the mobile nodes of an in-vehicle nv6 network. So, it is .important for the mobile router to assure reliable connection and a sufficient data rate for the group of nodes behind it. To provide reliability, this paper proposes an adaptive multihoming architecture of multiple mobile routers. Proposed architecture makes use of different mobility characteristics of different vehicles. Simulation results with different configurations show that the proposed architecture increases session preservation thus increases reliability and reduces packet loss. We also show that the proposed architecture is adaptive to heterogeneous access environment which provide different access coverage areas and data rates. The result shows that our architecture achieves sufficient data rates as well as session preservation.

• Journal of Drive and Control
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• v.12 no.4
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• pp.15-20
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• 2015

Unlike a typical metal spring, a gas spring uses compressed gas contained in a cylinder and compressed by a piston to exert a force. A common application includes automobiles where gas spring are incorporated into the design of open struts that support the weight of tail gate. They are also used in furniture such as office chairs, and in medical and aerospace applications. The gas spring works by the application of pressurized gas (nitrogen) contained in a cylinder. The internal pressure of the gas spring greatly exceeds atmospheric pressure. This differential in pressure exists at any rod position and generates an outward force on the rod, making the gas spring extend. In this paper, we investigated the dynamic characteristics of a gas spring on an automotive tail gate system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.269-270
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• 2022

자율주행 자동차의 개발을 위해서는 다양한 기능 평가, 성능 평가, 안전성 평가 등이 필수적이다. 이러한 평가는 컴퓨터 시뮬레이션과 실제 주행을 통해 이뤄질 수 있으며, 현실의 도로 상황을 고려한 단위시험환경들을 조합 구성한 통합시험환경에서 수행하는 것이 일반적이다. 여기서 단위시험환경은 도로망 구성, 장애물, 표지판 등의 정보를 포함하는 정밀도로지도를 기반으로 주행차량수, 보행자, 기상환경, 동적 이벤트 요소 등을 고려하여 구성할 수 있다. 본 논문에서는 이러한 단위시험환경을 구성하기 위한 정밀도로지도 처리 방법을 소개한다. 구체적으로는 정밀도로지도 처리를 포함하는 데이터 파이프라인을 설계하고, 정밀도로지도 객체분석을 통해 시험환경의 특성 및 상호 유사성을 파악한다. 국토지리정보원에서 배포한 정밀도로지도를 사용하여 객체를 추출하고 분석하는 실험을 수행했으며 전반적인 동작 상태를 확인했다. 개발한 소프트웨어는 향후 자율주행 학습을 위한 단위 및 통합 시험환경 구축 및 법규 및 규제 대응 서비스 시나리오의 구성에 활용할 예정이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.10
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• pp.931-940
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• 2017

This paper describes a predictive fault diagnosis algorithm for autonomous vehicles based on a kinematic model that uses a sliding mode observer. To ensure the safety of autonomous vehicles, reliable information about the environment and vehicle dynamic states is required. A predictive algorithm that can interactively diagnose longitudinal environment and vehicle acceleration information is proposed in this paper to evaluate the reliability of sensors. To design the diagnosis algorithm, a longitudinal kinematic model is used based on a sliding mode observer. The reliability of the fault diagnosis algorithm can be ensured because the sliding mode observer utilized can reconstruct the relative acceleration despite faulty signals in the longitudinal environment information. Actual data based performance evaluations are conducted with various fault conditions for a reasonable performance evaluation of the predictive fault diagnosis algorithm presented in this paper. The evaluation results show that the proposed diagnosis algorithm can reasonably diagnose the faults in the longitudinal environment and acceleration information for all fault conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.61-67
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• 2023

The rise of 5G and the proliferation of smart devices have underscored the significance of multi-access edge computing (MEC). Amidst this trend, interest in effectively processing computation-intensive and latency-sensitive applications has increased. This study investigated a novel task offloading strategy considering the probabilistic MEC environment to address these challenges. Initially, we considered the frequency of dynamic task requests and the unstable conditions of wireless channels to propose a method for minimizing vehicle power consumption and latency. Subsequently, our research delved into a deep reinforcement learning (DRL) based offloading technique, offering a way to achieve equilibrium between local computation and offloading transmission power. We analyzed the power consumption and queuing latency of vehicles using the deep deterministic policy gradient (DDPG) and deep Q-network (DQN) techniques. Finally, we derived and validated the optimal performance enhancement strategy in a vehicle based MEC environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.139-148
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• 2006

The dynamic characteristics of a bridge deduced by using the modeling techniques depend on its stiffness and mass calculated from its geometric model. This research develops the FE modeling techniques for a steel plate girder bridge with composite section. and proves their validity by comparing the results with those from actual measurement. The FE modeling techniques are divided into two categories--a simplified one and two-dimensional model and a detailed three-dimensional model. In the meantime, the dynamic responses of the bridge tested for this research were measured by the ambient vibration some of accelerometers were been attached to its upper slab girder under normal traffic load. The Cross Power Spectrum obtained from the measurement was used to analyze the dynamic characteristics by natural excitation techniques. The analytic results are compared to those of each FE modeling, and thereby the modeling techniques were proved to be valid.