• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.1
• /
• pp.80-86
• /
• 2008

In this study. the noise sources were identified and the noise and vibration were reduced for an industrial forklift. To identify the noise sourses, noise signals were measured by a microphone on a driver seat and these signals were analyzed with a waterfall plot. For this purpose, the gear mesh frequencies from the gear box of a reducer were not only investigated but noise/vibration sourses of an electric motor were also examined. Furthermore, the frequency response functions were obtained to confirm the vibration and noise sourses. It was found that severe vibration and noise were generated in the casing and the connecting part of the reducer. The severe vibration and noise could be reduced by a structure modification.

• Journal of the Korean Society of Industry Convergence
• /
• v.9 no.2
• /
• pp.105-110
• /
• 2006

Valve-housing parts in car steering system is a part of steering system and then take charge of the main functions for car steering system to reduce driver's handling-force. Recently it is still not developed reliable casting for many cars, so it produce as a Gravity casting which is more than triple for producing cost in Korea. In this research, we had conducted that 350t aluminum die casting is superior to mechanical property from established over 500t or not for Valve-housing, a parts of steering system which were produced as a cast-iron product and the most suitable conditions to extruding as die casting.

• KDI Journal of Economic Policy
• /
• v.44 no.3
• /
• pp.75-99
• /
• 2022

This paper analyzes job creation when the Korean economy transitioned to a knowledge economy from the 1990s to the 2010s. During this period, the ratio of service to manufacturing jobs increased, knowledge intensive industries grew, and job creation became geographically concentrated around Seoul. The changes slowed down in the 2010s, and overall job growth weakened. To analyze the effect of job creation driver industries during this period, the main part of which are knowledge intensive tradable service industries, on local service job creation, I use a modified version of the local labor market of Moretti (2010). I analyze the job changes during 1995-2005 and during 2006-2016 in 237 Si-Gun-Gu areas in the Census on Establishments datasets. I find that one manufacturing job creates 0.5 local service jobs and that one tradable service job creates 1.1 jobs within Gu areas of metro cities and 2.3 jobs in Si-Gun areas. The job creation relationship between the tradable and local service sectors was not altered in this period. As more jobs were created in the tradable sector driven by the transition to a knowledge economy, job creation overall remained active, with the opposite also being true.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.11
• /
• pp.2532-2537
• /
• 2012

In recent, the researches on driver assistance systems have been actively performed with development of vehicle industry. AVM(Around View Monitoring) Systems, a part of these systems, have been researching and developing. Existing AVM systems have been developed in the forms of embedded systems or a SoC (System on Chip) to provide view around vehicle in real time. However, if Car PC is equipped with in vehicle, AVM can be developed using only software without additional cost. In this study, we implemented AVM system which provides location information by adding the informations such as latitude, longitude and speed to functions of "Car PC" based AVM system. If storing function is added to the AVM system implemented in this study which provides location information, the system with storing function can be used as AVM black box system.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.1
• /
• pp.24-29
• /
• 2003

A 120kV/70A high voltage switch has been installed at Korea Atomic Energy Research Institute(KAERI) in Taejon to supply power with Korea Superconducting Tokamak Advanced Research(KSTAR) Neutral Beam Injection(NBI) system. NBI system requires fast cutoff of the flower supply voltage for protection of the grid when arc detected and fast turn-on the voltage for sustaining the beam current. Therefore the high voltage switch and arc current detection circuit are important part of the NBI power supply. There are much need for high voltage solid state switches in NBI system and a broad area of applications. This switch consisted of 100 series connected MOSFETs and adopted the proposed simple and reliable gate drive circuit without bias supply. Various results taken during the commissioning phase with a 100kW resistive load and NBI source arc shown. This paper presents the detailed design of 120kV/70A high voltage MOSFETs switch and simple gate drive circuit. Problems with the high voltage switch and gate driver during thefabrication and test and solutions are also presented.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.7C
• /
• pp.565-575
• /
• 2012

In the modern everyday life, cars the largest proportion of smart features that require mounting in a variety of smart devices and smart methods on have been developed. In this paper, the smart car among the main core of the safety management system optional for the control of drinking and drowsiness, as part of system development, will be drinking if you start your car automatically is to develop a system to avoid driving. For this, through image processing to analyze the driver's seat of the driver's facial color how to determine whether or not drinking alcohol is proposed. In particular, the system developed in this paper determines whether or not drinking alcohol before the face images without the need for alcohol after only a unique color change of the face appears to target only way to determine whether drinking and actual alcohol control center of a smart car safety control management system can be applied effectively. The experiment was done in 30 patients after drinking appears face color changes of them. We also perform an analysis on the statistical significance of the experimental results to verify the effectiveness of the proposed method.

• The KIPS Transactions:PartA
• /
• v.13A no.6 s.103
• /
• pp.517-524
• /
• 2006

In cluster computers, it is essential to Implement the single I/O space(SIOS) supporting integrated I/O substructure to efficiently process I/O intensive applications. SIOS service provides with global I/O address space to directly access peripherals and hard disks in its own or remote nodes from any node in the cluster computer In this thesis, we propose the implementation method of SIOS in Linux clusters by using only freewares. This method is implemented at device driver level that uses Enhanced Network Block Device(ENBD) and file system level that uses S/W RAID and NFS. The major strengths of this method are easiness of implementation and almost no cost due to using freewares. In addition, since freewares used are open sources, it is possible to apply this method to other platforms with only slight modification. Moreover, experiments show that I/O throughputs are up to 5.5 times higher in write operations and approximately 2.3 times higher in read operations than those of CDD method that uses the device driver developed at kernel level.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.5
• /
• pp.448-456
• /
• 2011

In this paper, we proposed a LED driver that allows to use a long lifetime MLCC with small voltage capacity to replace the electrolytic condenser that has been used at the output part by storing only the voltage fluctuation due to temperature variation in the output condenser. The proposed LED driver can allow to use a long lifetime MLCC with small power loss as the output condenser instead of the conventional electrolytic condenser with short lifetime because it stores only the voltage fluctuation due to the temperature variation of the LED light source in the output condenser by connecting the output condenser with the input power supply in series in the basic topology of the conventional boost DC/DC converter. In this study, we performed a simulation to verify the conventional DC/DC converter and the proposed DC/DC converter. It was shown that the DC/DC converter proposed through the experiment allows to use MLCC as the output condenser and the efficiency can be improved.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.11
• /
• pp.4751-4755
• /
• 2011

This study investigates the plastic suspension assembly which is installed on inside of vehicle seat and support passenger's back to supply the comfortable ride performance. It aims to develop the structural design in order to support driver's back uniformly and assemble seat back frame with plastic suspension effectively. The part of suspension is designed by considering the body pressure distribution of driver and it has the same size as the practical model on simulation analysis. It is confirmed that the analysis result of plastic suspension approaches the practical measured values and the better body pressure distribution can be obtained as compared with the existing wire type.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.20 no.6
• /
• pp.899-915
• /
• 2018

In this study, in order to construct an eco-friendly advanced road transportation network, the multi-layer tunnel, which is a small-sized car road, is designed to have a height of less than 60 cm. However, the shape of the tunnel is low and the height of the traffic sign is small. In order to solve these problems, traffic sign characters were designed in three dimensions, and the possibility of applying the design of the three - dimensional sign that can obtain greater visibility than the existing signs at the same distance and the possibility verification through virtual simulation were performed. The three-dimensional sign is horizontally installed on the ceiling of the multi-layer tunnel. To be seen vertically, it is enlarged by a certain ratio by the perspective, and the width and height are enlarged. Respectively. In addition, 3D simulation was performed to verify the visibility of the stereoscopic signs when the driver ran through the stereoscopic sign design specifications. As a result of the design and experimental study, it was confirmed that the stereoscopic sign could be designed through the theoretical formula and that it could provide the driver with a larger traffic sign character because there is no limitation of the facility limit compared to the existing vertical traffic sign. Also, we confirmed that it can be implemented in the side wall by using the stereoscopic sign design principle installed on the ceiling part. It was confirmed that the design of the stereoscopic sign can be designed to be smaller as the distance that the driver visually recognizes the sperm is shorter, the height of the protrusion vertically at the lower part of the stereoscopic sign becomes higher. As a result of 3D simulation running experiment based on the design information of the stereoscopic sign, it was confirmed that the stereoscopic sign is visually the same as the vertical sign at the planned distance. Although the detailed research and institutional improvement of stereoscopic signs have not been made in Korea and abroad, it is evolved into a core technology of new road traffic facilities through various studies through the possibility of designing and applying stereoscopic signs developed through this study Expect.