• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.1-8
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• 2017

This paper presents the development of an adaptive cruise control (ACC) system, which is one of the typical advanced driver assist systems, for 4-wheel drive hybrid in-wheel electric vehicles. The front wheels of the vehicle are driven by a combustion engine, while its rear wheels are driven by in-wheel motors. This paper proposes an adaptive cruise control system which takes advantage of the unique driveline configuration presented herein, while the proposed power distribution algorithm guarantees its tracking performance and fuel efficiency at the same time. With the proposed algorithm, the vehicle is driven only by the engine in normal situations, while the in-wheel motors are used to distribute the power to the rear wheels if the tracking performance decreases. This paper also presents the modeling of the in-wheel motors, hybrid in-wheel driveline, and integrated ACC control system based on a commercial high-precision vehicle dynamics model. The simulation results obtained with the model are presented to confirm the performance of the proposed algorithm.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.119-128
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• 2004

With the growing traffic density and increasing comfort requirements, the automation of the drive train will gain importance in vehicles. The automatic clutch actuation relieves the drivers especially in urban driving and stop-and-go traffic conditions. This paper describes the dynamic modeling of a clutch actuator and clutch spring. The dynamic model of the clutch system is developed using MATLAB/Simulink, and evaluated by experimental data using a test rig. This performance simulator is useful to develop the clutch-by-wire (CBW) system for an automated manual transmission (AMT). The electro-mechanical type CBW system is also implemented as an automatic clutch for AMT. The prototype of CBW system is designed and implemented systematically, which is composed of an electric motor, worm gear and slider-crank mechanism. The test rig is developed to perform the basic function test of the automatic clutch, and the developed prototype is validated by the experimental data on the test rig.

• Korean Journal of Veterinary Service
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• v.35 no.1
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• pp.39-45
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• 2012

This survey aims to provide information on the pattern of distress in wild avian animals in Gangwon province. This survey is based on 315 wild avian which were rescued by the Kangwon University Wildlife Rescue Center. The data was collected at the Wildlife Animal Center from September 2007 to August 2010, and by analyzing the shape of the wild animals killed or injured, the center seeks an efficient and systematic way to manage such distress. There are 55 species found, in this study including 40 common kestrel, 34 eurasian eagles, 20 common buzzards, 20 collared scops owls, 19 oriental scops owls, 16 brown hawk owls and 160 others. These are the results of the survey: 129 (40.3%) of 315 avian birds were found between June and August. Many cases in that term were observed falling from the nest or losing their mother because of unskilled flight during the breeding season's flight practicing process. Between November and December, 64 individual (20.3%) were found, and it's the second largest number. The main reasons for these results were starvation and exhaustion from the winter migratory season. The results indicated that the main reason for avian distress came from the following: collision with architecture windows in 73 cases (23.2%), starvation and exhaustion in 63 cases (20.0%), collision with vehicles in 51 cases (16.2%), becoming orphaned in 69 cases (21.9%), trespassing into buildings occurred in 19 cases (6.0%), collision with electric wires in 18 cases (5.7%), poaching materials in 13 cases (4.1%), becoming entangled by fishing wire and other miscellaneous materials in 4 cases (1.3%), infection from parasites in 4 cases (1.3%), toxicosis from such toxins like agricultural chemicals in 1 case (0.3%). Overall, the purpose of this investigation was to analyze cases of avian distress in Korea's wildlife. This study used areas, seasons and causes to understand origins of these animals distress. So that it can be utilized for organized wild avian rescue and treatment.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.247-252
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• 2012

Of late, the development of advanced batteries with high power density and capacity has been indispensible for pushing ahead with much wider applications to electric vehicles and smart IT devices. However, a conventional Li-ion battery contains a limited energy density due to various technological challenges such that other types of Li batteries including Li-S and Li-air have been extensively studied due to their interestingly high energy capacities. Sulfur and oxygen, of which both are cathode materials, showing similar physicochemical characteristics have widely been available which may also contribute to the commercialization of these batteries. In this review, we introduce some perspectives in improving these advanced Li batteries through several approaches such as the provision of porous cathode structures, the optimization of cathode-electrolyte interfaces and the modification of Li anodes.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.3
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• pp.73-82
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• 2011

Most of countries start to restrict the emission gases of vehicles especially CO2 because of the global warming. Many vehicle companies including Toyota have launched various HEVs to satisfy the restriction laws and to improve the vehicle's efficiency. However, development for heavy-duty hybrid system is not plentiful rather than the passenger car. In this study, we choose the optimal size of engine, motor and battery for heavy-duty hybrid systems using dynamic programming. Also we analyze the correlation of the system's cost and efficiency because the added cost of vehicle to make the hybrid system is very important factor for the manufacturing companies. Finally, this study suggests a method to choose the appropriate system components size considering its performance and the cost. With this method, it is possible to select the component size for various systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.147-156
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• 2008

As the management of fuel efficiency becomes globally reinforced in attempts to find an environment-friendly vehicle that will operate against global warming, the interest in and the demand for the type of vehicle with a high-efficiency diesel engine using light oil. However, it also emits a greater amount of PM (particulate matter) and NOx than emissions from vehicles using other types of fuels. Therefore, the DME (Dimethyl Ether), an oxygen containing fuel draws attention as an alternative fuel for light oil that can be used for diesel engines since it generates very little smoke. But to develop and compare performance of an electric controlled common-rail DME engine, engine tests requires optimized injection conditions at required engine RPM and engine torque. These injection conditions cannot be set freely and the data configuration through the experimentally repeated application requires much time as well as a significant amount of errors and effort. The object of this study is to configure the basic injection map using the results of the DME engine experiments performed so far. For this, in this study, the functionalization of the required equations were performed along with the basic review of the factors that had influence on the data map. Through this, the information on the injection pressure, injection amount, injection duration, injection timing, etc. under certain operation condition could be obtained.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.157-166
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• 2017

The Fuel Cell Electric Vehicle(FCEV) is recently evolving into a new trend in the automobile industry due to its relatively higher efficiency and zero greenhouse gas(GHG) emission in the tailpipe, as compared to that of the conventional internal combustion engine vehicles. However, it is important to analyze the whole process of the hydrogen's life cycle(from extraction of feedstock to vehicle operation) in order to evaluate the environmental impact of introducing FCEV upon recognizing that the hydrogen fuel, which is used in the fuel cell stack, is not directly available from nature, but instead, it should be produced from naturally available resources. Among the various hydrogen production methods, ${\sim}54.1%^{8)}$ of marketed hydrogen in Korea is produced from naphtha cracking process in the petrochemical industry. Therefore, in this study, we performed a well-to-wheels(WTW) analysis on the hydrogen fuel cycle for the FCEV application by using the GREET program from the US Argonne National Laboratory with Korean specific data. As a result, the well-to-tank and well-to-wheel GHG emissions of the FCEV are calculated as 45,638-51,472 g $CO_2eq/GJ$ and 65.0-73.4 g $CO_2eq/km$, respectively

• Journal of the Korean Magnetics Society
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• v.24 no.5
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• pp.160-164
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• 2014

In this paper, an efficient robust design utilizing an enhanced Taguchi method is proposed to reduce cogging torque of a BLDC motor in the presence of design uncertainty. To overcome defects of the conventional Taguchi method in dealing with a generalized robust design problem, a penalty function and an optimal level searching technique are newly introduced. In order to verify the proposed method, a 5 kW, rated speed of 2,300 rpm, rated torque of 20 Nm BLDC motor for driving electric vehicles is optimized. Then, the robust design is compared with conceptual and deterministic ones in terms of the cogging torque, rated torque and torque ripple.

• Journal of Drive and Control
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• v.17 no.3
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• pp.26-32
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• 2020

In modern society, the energy-saving problem of industrial vehicles is economically and environmentally critical. Energy savings using the potential energy of forklifts are one of the viable solutions to resolving this problem. The basic concept of this study is to operate the hydraulic motor and recharge the battery using the flow rate from the cylinder when loading heavy objects and lowering the fork. To save energy, the torque and rotational speed of the generator should be optimized according to the load and descent speed to increase efficiency. To this end, we propose a system that optimizes energy saving efficiency by controlling the swashplate angle of the variable hydraulic motor through the GA(Genetic-Algorithm). The results were verified by building and comparing fixed motor models and variable motor models using the AMEsim. The results of the study show that the proposed optimized swashplate angle increases the energy saving efficiency by approximately 6%-8%, depending on the working conditions.

• Smart Structures and Systems
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• v.16 no.3
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• pp.383-399
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• 2015

Today, as railways increase their capacity and speeds, it is more important than ever to be completely aware of the state of vehicles fleet's condition to ensure the highest quality and safety standards, as well as being able to maintain the costs as low as possible. Operation of a modern, dynamic and efficient railway demands a real time, accurate and reliable evaluation of the infrastructure assets, including signal networks and diagnostic systems able to acquire functional parameters. In the conventional system, measurement data are reliably collected using coaxial wires for communication between sensors and the repository. As sensors grow in size, the cost of the monitoring system can grow. Recently, auto-powered wireless sensor has been considered as an alternative tool for economical and accurate realization of structural health monitoring system, being provided by the following essential features: on-board micro-processor, sensing capability, wireless communication, auto-powered battery, and low cost. In this work, an original harvester device is designed to supply wireless sensor system battery using train bogie energy. Piezoelectric materials have in here considered due to their established ability to directly convert applied strain energy into usable electric energy and their relatively simple modelling into an integrated system. The mechanical and electrical properties of the system are studied according to the project specifications. The numerical formulation is implemented with in-house code using commercial software tool and then experimentally validated through a proof of concept setup using an excitation signal by a real application scenario.