• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.3
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• pp.110-113
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• 2011

Platform Screen Door, PSD, is a device that seeks to prevent accidents with regards to falling off the platform and getting trapped between the trains, achieve improvements on the cleanliness of the air, address the accessibility issue of the disabled and the elderly and provide fresher environment on the platform in general. This is achieved by preventing health hazards and accidents from occurring through installation of fixed and moving doors between rail, tram and subway platforms and the railway. Domestic firms have achieved domestic production to a large degree in various Control Units including the Overall Control Unit and RF devices through investments in technology. Despite this, full domestic production of the core of the PSD system, Door Control Unit, DCU, is not yet achieved, having to install PSDs in a relatively short period of time. Currently, controllers with DC motors are developed for installation or one is faced with having to import foreign produced controllers. In this research, the control unit prototype using the BLDC motor was domestically produced. The performance of the control unit was rigorously tested through installation on Eun-Ha Rail on Wol-Mi Island.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.867-872
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• 2007

A tracked robot has an excellent mobility on the rough terrain. Especially, a tracked robot for driving has to get structural function in the every field. In this paper, we propose a tracked robot of a small rear wheel typed. Also compared and estimated a driving analysis about the tracked robot in considered the general environment. Compared 2 models are different in size of rear wheels but front wheels are same size each other. From comparing model, the radius of front wheels is 100mm and the radius of rear wheels is 100mm. The radius of front wheels is 100mm and the radius of rear wheels is 70mm from proposed tracked robot. Depend on these radiuses of values we are known driving torque values of an actuating wheel using Recurdyn. And estimated stress of rotated track by an actuating wheel using Ansys. finally, the designed robot has size of $600mm\;{\times}\;330mm\;{\times}\;150mm$, weight is 27kg and the tracked robot is actuated by 2 geared DC motors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.949-954
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• 2011

This paper presents a comparative study on motor characteristics with specific consideration of radial vibration force in interior permanent magnet synchronous motors (IPMSM) according to pole/slot combinations. Three IPMSM models, 16-pole/15-slot design, 16-pole/18-slot design and 16-pole/24-slot design are built, in which 16-pole/15-slot and 16-pole/18-slot designs provide high winding factor and 16-pole/24-slot design is known as a general pole/slot combination. By coupling finite element analysis (FEA) with equivalent circuit method, motor characteristics, back electro-motive force (Back-EMF), inductances, cogging torque, etc. as well as machine output performances are analyzed and compared. The radial vibration force (RVF) distribution in air gap causing stator vibration and noise is interested. It is expected that this study help with appropriate choice of pole/slot combination in IPMSM design.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.73-84
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• 2004

In general, static firing test is conducted before flight in order to obtain data such as thrust. pressure, temperature and strain, which show the characteristics of rocket motors. But the measured thrust of the obtained data is especially distorted by the effects of dynamic characteristics of thrust stand so that it is difficult for us to determine the exact value of peak thrust and rising time etc., which represent the performance of rocket motor. This paper, therefore. verified the causes of distortion of measured thrust, and proposed the theoretical method to estimate the true thrust from the distorted thrust. And also the proposed method was applied to virtual thrust stand using computer simulation, and showed good result. As a result of that, the proposed method was proven to be valid and applicable to estimate distorted thrust.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.1
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• pp.77-83
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• 2016

Intricate deflection requires many conventional actuators (motors, pistons etc.), which can be financially and spatially wasteful. Novel smart soft composite (SSC) actuators have been suggested, but fabrication complexity restricts their widespread use as general-purpose actuators. In this study, a hybrid manufacturing process comprising 3-D printing and casting was developed for automated fabrication of SSC actuators with $200{\mu}m$ precision, using a 3-D printer (3DISON, ROKIT), a simple polymer mixer, and a compressor controller. A method to improve precision is suggested, and the design compensates for deposition and backlash errors (maximum, $170{\mu}m$). A suitable flow rate and tool path are suggested for the polymer casting process. The equipment and process costs proposed here are lower than those of existing 3D printers for a multi-material deposition system and the technique has $200{\mu}m$ precision, which is suitable for fabrication of SSC actuators.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.58-68
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• 2016

The propellant mixer for charging of solid rocket motors is one of the most important equipments. For the propellant mixer is export control item, it's hard to purchase it directly from abroad. The Mixer was developed locally to overcome export control which precludes us from import. This paper includes the introduction for general mixers and the process of mixer development progressed by LIGNex1. Finally, The mixer is verified the performance using measurements of clearance between blade-blade and blade-bowl and flow simulation with ADINA.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.13-22
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• 1997

Power flow characteristics of a hydro-mechanical transmission system(HMT) are investigated for tracked vehicle in steering. A HMT consisting of two hydrostatic pump motors(HST), several planetary gear trains and steer differential gear is considered. In order to obtain the direction and magnitude of the power flow of the HMT, network theory for the general power transmission is used. Network model for the HMT in steering is developed, which consists of shafts, nodes and transmission elements such as clutch, gear, etc. Power flow analysis procedure consists of two stages : (1) traction force analysis in steering, (2) power flow analysis in HMT. Torque and speed of every transmission element of the HMT is determined from the network analysis. Also, efficiency, mechanical and hydraulic power loss including HST, are obtained. In addition, the regenerative power flow resulting from steering can be studied in graphic display. The power flow analysis program(PCSTEER) developed in this work can be used as a useful design tool for the tracked vehicle with HMT.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.234-240
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• 2014

Driving-related injuries associated with elderly drivers are on the rise, although the overall rate of driving-related injuries has decreased. To determine the causes of this trend, we researched existing vehicle systems that use different sensors and signals to promote safe driving. We found that although the systems alert drivers to potential collisions and assist them in finding a location easily, they were created by people who rarely use the systems in their daily lives. For the most part, they're not created by people with driving difficulties caused by health problems, which in turn often afflict the elderly. To address this issue, we analyzed the drawbacks of the current systems and used a focus group of people with body conditions that have declined due to age to discover the problems they encounter while driving. With the focus group, we used diverse research activities, such as observation and interview to demonstrate how new system concepts could be developed for the elderly. Finally, we propose that adequate system concepts for the elderly would improve driving safety and provide a more enjoyable driving environment for this population.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.304-308
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• 2007

Failure phenomena in uni-axial tension test were experimentally and numerically investigated for AA6111-T4, AA5083-H18 and DP-Steel, which were friction-stir welded with the same and different thicknesses. Forming limit diagram(FLD) was measured using hemispherical dome stretching tests for base materials and also predicted by Hill's bifurcation and M-K theories for welded areas. Finite element simulations well predicted hardening behaviors, failure locations as well as failure patterns for the uni-axial tension tests especially utilizing very fine meshes and FLD along with stress softening.

• The Korean Journal of Rehabilitation Nursing
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• v.13 no.2
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• pp.97-104
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• 2010

Purpose: This study was to investigate difficulties in daily activities and tingling from patients having treatment of FOLFOX chemotherapy after colon resection. Method: This study included 103 patients hospitalized for FOLFOX chemotherapy in one of the university affiliated hospital from August 1, 2008 through September 30, 2009. Data were collected using the questionnaire comprised general symptoms, tingling, difficulties in daily activities and coping behavior. Using the SPSS 14.0 program, data analytic methods include Chi-Square test, ANOVA, Scheffe's test. Results: The tingling sensation occurred in hands, feet, mouth, throat. Contacts with cold objects and the number of chemotherapy cycle worsen tingling sensation. Patients experienced difficulties in daily activities such as personal hygiene, kitchen work, eating cold food, sleeping cold, using fine motors like button up, writing, or using knife. The coping behavior included drinking warm water, sleeping warm, using gloves and socks, wearing comfortable shoes, massaging hands and getting help from supporters. Conclusion: An educational guideline for promoting coping behavior to relieve tingling sensation and difficulty in daily living in patients with FOLFOX chemotherapy is needed.