• Journal of Drive and Control
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• 제17권3호
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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.

• Journal of Digital Convergence
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• 제15권1호
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• pp.217-225
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• 2017

A study proposes possibility of new IoT measuring system blended with a smart device. The research serves the best cultivation information for domestic fruit's enhancement of competitive power and also develops a glucose measuring system by which people manage fructose with the mobile device. The mobile glucose tester is designed with a form of accessory which has high portability and utility because the product connects an existing analogy refractometer to the smart phone. You can check the glucose rates data by commodity, region, and season then save measurement results with server in real time for an exclusive application. It's possible to serve the glucose map, graph, and data list through the web service. This is very useful to do collect, analyze, and process the glucose data.

• Journal of Digital Contents Society
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• 제11권1호
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• pp.91-97
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• 2010

Flash memory has been used by many digital devices for data storage, exploiting the advantages of non-volatility, low power, stability, and so on, with the help of high integrity, large capacity, and low price. As the fast growing popularity of flash memory, the density of it increases so significantly that its entire address mapping table becomes too big to be stored in SRAM. This paper proposes the associated page address cache with an efficient table management scheme for hybrid flash translation layer mapping. For this purpose, all tables are integrated into a map block containing entire physical page tables. Simulation results show that the proposed scheme can save the extra memory areas and decrease the searching time with less 2.5% of miss ratio on PC workload and can decrease the write overhead by performing write operation 33% out of total writes requested.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제29권10호
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• pp.1416-1429
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• 2005

In order to meet the increasing competitive pressures coupled with higher demands for component quality, whirling machines have been at the cutting edge of the automobile industry for more than 25 years. The hard whirling process can save on machining time and operation elimination. Hard whirling is done dry, without coolant. The chips carry away nearly all of the heat during cutting, leaving the workpiece cool and minimizing any thermal geometry variations. The surface finish and profile accuracy are close to grinding quality. Whirling machines usually consist of four major parts; 1) loading system that requires the necessary axial speeds, 2) head stock that needs high precision clamping and positioning system at the chuck and tailstock, 3) whirling unit that demands the high cutting speeds and cutting power fer cutting deep thread profiles and 4) unloading system that requires an easy workpiece unloading. Also, capabilities of the whirling machine can be improved by attaching a vision system to the machine. Most of whirling machines in Korean automobile industry are imported from the Leistritz company, Germany and the Hasegawa company, Japan. Tn this paper, a basic research will be performed to improve and enhance the existing whirling machines. Finally, a new Korean whirling machine will be proposed and developed.

• Journal of Drive and Control
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• 제10권2호
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• pp.7-12
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• 2013

In this study, a wire/wireless communication system transmitting the operation data of engine from the ER (Engine Room) to the engine controller of ECR(Engine Control Room) has been developed through the communication of ISM(Industrial Science Medical) Band for the test operation environment improvement of medium speed engine. This wire/wireless communication system is composed of the RTU (Remote Terminal Unit) gathering and transmitting engine data as well as the MCU (Master Control Unit) receiving engine status information from the RTU to be sent to the engine controller (PLC). Through this study, a trial product of RTU and MCU has been manufactured. A test bench that has made temperature, pressure and pick-up sensor into a module for the local test of prototype was produced a test bench. In addition, at the same time save the data to a Web server and the smart phone real-time monitoring system has been developed using Wi-Fi communications. The ultimate objective of this study is to develop a wireless smart phone monitoring system of engine for the operator of engine to be able to monitor and control engine status even from the outside of engine room and control room based on this study.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제48권12호
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• pp.73-81
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• 2011

As high speed digital systems continue to use components with faster edge rate and clock speeds, transmission of the digital information, it can bring about many troubles. The increasing requirement for controlled impedance PCBs becomes both a critical success factor and a design challenge to implement a system. Especially, the noise sources in high frequency digital systems include the noise in power supply, ground and packaging, and they destroy the fidelity of signals. Therefore PCB design with impendence matching is needed to improve fidelity of signal in H/W. In this paper, we have developed an impedance control and analysis tool for multi-layer PCB design, and simulates the tracks controlled impedance with the test coupon. So, it can save the design time and support the economical PCB design.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제19권3호
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• pp.245-252
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• 2007

The important problems from the point of view of preventing global warming are to save the power consumption of automotive air-conditioning systems and reduce the refrigerant amount filled. To achieve such requirements, integral receiver/dryer (R/D) condensers were developed recently. Typical integral R/D condensers have extra headers that play the role of R/D. Except an extra header and somewhat complex tube array resulting from the extra header, the most integral R/D condensers have almost the same specification that tube has multi channels, fin has louvers, flow in tube is parallel, etc. When integral condensers are applied, it is known that the refrigerating effect increases, resulting from the increase of subcooling degree in condenser, and the refrigerant amount used saves. In spite of several merits, integral condensers have not been applied a lot. That is why there is an uncertainty in performance, using integral condensers. The objective of this study is to theoretically optimize the tube array in an integral R/D condenser that is really being applied to some vehicles. The tube array has a great effect on the performance of the integral condenser as well as common ones. Through computer simulation, we could see that the tube array, 14-6-3-5-3-4, in the same condenser was the best, comparing heat release rate, pressure drop, etc. to the real array, 17-5-3-3-2-5. It should be noted that the optimization is based on the condenser performance only.

• Journal of the Institute of Electronics Engineers of Korea SP
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• 제45권6호
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• pp.1-8
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• 2008

This paper introduces three efficient frame selection schemes to reduce the computation complexity for the multi-reference and variable block size Motion Estimation (ME). The proposed RSP (Reference Selection Pass) scheme can minimize the overhead of frame selection. The MFS (Modified Frame Selection) scheme can reduce the number of search points about 18% compared with existing schemes considering the motion of image during the reference frame selection process. In addition, the TPRFS (Two Pass Reference frame Selection) scheme can minimize the frame selection operation for the variable block size ME in H.264/AVC using the character of selected reference frame according to the block size. The simulation results show the proposed schemes can save up to 50% of the ME computation without degradation of image Qualify. Because the proposed schemes can be separated from the block matching process, they can be used with any existing single reference fast search algorithms.

• Journal of National Security and Military Science
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• 통권8호
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• pp.169-238
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• 2010

The year 2010 is the 60th anniversary commemorating the Korean War. China intervened in the Korean War with the logics such as "To Resist the U.S.'s Aggression and Aid North Korea," "Save Endangered Home & defend Nation," and "If the Lips Are Gone, the Teeth Will Be Exposed to the Cold or If One of Them Falls, the Other is in Danger." However, China had a deep and long connection with North Korea through 1st Chinese Civil War, war against Japan imperialism, and 2nd Chinese Civil War. China has consulted with Kim Il-sung on his invasion of South Korea at the initial stage of development and played a casting vote role in the execution of the invasion plan. During the Korean War, the PLA supported the North Korea's regime by its action, and made the Korea Peninsula divide into two semi-permanently. Even after the war, China continues to maintain relations with North Korea by helping North Korea build the Kim Il-sung's Kingdom. Currently, whenever any issue related to North Korea rises in the international society, China definitely gets involved in those issues and exercises its power. Conditionally 'either armed aggression or, and wartime' in North Korea, China would follow the "Clause of Military Auto Intervention." In addition, China is very likely to establish refugee camps for North Koreans in the Northeastern-Three-Province and to provide rear bases or guerrilla camps for pro-Chinese sects. Furthermore, voluntarily playing a role as spokesman of North Korean Regime in the international society, China will exercise enormous influence on the reunification of the Korean Peninsula.

• Journal of the Korean Society for Railway
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• 제16권4호
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• pp.241-245
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• 2013

In the case of the existing train control system, the driver monitors the condition of the vehicle through a composite controller device that displays various information on a screen in the vehicle. However, when problems arise such as car trouble, it is difficult for the drivers to take action immediately. In addition, maintenance personnel have to manually save data one by one after storing the vehicle to analyze control information of the main devices such as the brake controller and auxiliary power. To improve these points, a system that sends and receives all information in real time should be established by installing a sensor communication network and a surveillance system. This study attempts to improve the safety and maintenance of rail vehicles by suggesting a standardized method for train control and surveillance system.