• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.99-105
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• 2017

As cities develops, road systems become more and more complicated. These days people depends on navigation systems when walking as well as driving cars. General navigation systems are either installed in cars or exists as smart phone applications. Therefore, it is very difficult to use them while walking or riding bicycles. Moreover, disabled person cannot use them to find his destinations. In this paper, we propose a bracelet navigation system for walkers and disabled people, and describe the design and implementation of such a device. This navigation will help not only walkers and people riding bicycle but also disabled people to actively participate their social activities.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.492-498
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• 2005

A linear motor damper based on the linear motor principle is developed to suppress structural vibration. This paper deals with the design, analysis, and manufacture of the linear motor damper. It is designed to be able to move the auxiliary mass of 1500kg, up to $\pm250mm$ stroke. The control algorithm was designed based on LQG control logic with acceleration feedback. Through performance tests, it was confirmed that the developed hybrid mass damper has reliable feasibility as a control device for structural control. In addition, the linear motor damper is more economical than both hydraulic and electric motor driving mass damper with respect to simple structure and low maintenance cost. A series of performance tests of the linear motor damper system were carried out on the full-scale steel frame structure in UNISON Corporation. Through the performance tests, it was confirmed that acceleration levels are reduced down 10dB for first mode of structure

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.4
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• pp.81-87
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• 2016

Recently, as the heterogeneous network (HetNet) has been deployed widely to support various kinds of Radio Access Networks(RANs) with a combination of Macro, Pico, and/or Femto cells, research and standardization efforts have been very active regarding the concept of Licensed Shared Access (LSA) for supporting spectrum sharing. In order for a mobile device to efficiently support the spectrum sharing, the mobile device shall be reconfigurable, meaning that its radio application code has to be adaptively changed in accordance with the hopping of desired spectral band. Especially, Working Group 2 (WG2) of Technical Committee (TC) Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI) has been a main driving force for developing standard architecture for Multi-mode Mobile Device (MD) that can be applied to the LSA system. In this paper, we introduce the Multi-mode MD architecture for supporting LSA-based spectrum sharing. An implementation of a test-bed of Multi-mode MD is presented in order to verify the feasibility of the standard MD architecture for the purpose of LSA-based spectrum sharing through various experimental tests.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.65-70
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• 2012

Torque fluctuation of engine generate gear rattle noise of transmission and many researches have been studied to decrease rattle noise by adjusting clutch damper system. So design optimization of clutch system is very important to decrease rattle noise and need knowing clutch dynamic torque at real vehicle driving condition. This makes it possible to measure clutch dynamic torque by using a small-size magnetic sensor. We install a small-size magnetic sensor on the input shaft of the transmission and measure the relative angular displacement between clutch hub and disc plate. We can obtain the clutch torque correspond to the angular displacement in the clutch torsional characteristics test. The object of this research is to measure clutch dynamic torque on real vehicle condition. Therefore, Clutch dynamic torque is very useful for investigating operating range of clutch according to engine torque and predicting the damping performance of torsional vibration on the powertrain.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.3
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• pp.144-148
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• 2001

For the purpose of developing capacitive humidity sensor having interdigit electrodes, interdigit electrode was modeled and simulated to obtain capacitance and sensitivity as a function of geometric parameters like the structural gap and thichness. For the development of ASIC, switched capacitor signal conditioning circuits for capacitive humidity sensor were designed and simulated by cadence using 0.25um CMOS process parameters. The signal conditioning circuits are composed of amplifier for voltage gain control, and clock generator for sensor driving and switch control The characteristics of the fabricated sensors are; 1) sensitivity is 9fF/%R.H., 2) temperature coefficient of offset(TCO) is 0.4%R.H./$^{\circ}C$, 3) nonlinearity is 1.2%FS, 4) hysteresis is 1.5%FS in humidity range of 3%R.H. ${\sim}$ 98%R.H.. The response time is 50 seconds in adsorption and 70 seconds in desorption. Fabricated process used in this capacitive humidity sensor having interdigit electrode are just as similar as conventional IC process technology. Therefore this can be easily mass produced with low cost, simple circuit and utilized in many applications for both industrial and environmental measurement and control system, such as monitoring system of environment, automobile, displayer, IC process room, and laboratory etc..

• Journal of the Korean Magnetics Society
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• v.20 no.6
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• pp.234-238
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• 2010

Solenoid diaphragm fuel pump, which to replace mechanical fuel pump system by utilizing cam-shaft driving force, is in the spotlight for being a high efficient green car component. However, there is a drawback in power consumption as a solenoid diaphragm fuel pump only relies on solenoid for its flux needed in reciprocating motion. Therefore, this research proposes permanent magnet type VCM (Voice Coil Motor) fuel pump system to minimized power consumption. Furthermore, the study compares and analyzes power consumption and dynamic performance between the current and the former solenoid diaphragm pump by conducting finite element analysis with the commercial electromagnetic solver, MAXWELL.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.1
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• pp.19-25
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• 2011

This study presents the design of digital amplifier.controller for a proportional control valve and the development of PID discrete control scheme by using RCP(Rapid Controller Prototyping) system. RCP system is the device to embed the control code developed in PC into the microcontroller on-site. Ramp input test using the digital amplifier.controller developed in this study was carried out for the proportional control valve of domestic production and Bosch Rexroth respectively. The instability problem occurred around maximum displacement of localized valve spool at ramp input test was solved by supplementing offset current to the duty ratio of PWM(Pulse Width Modulation) driving signal to the solenoid. The comparison of test results between localized proportional control valve and Bosch Rexroth's product shows that the characteristics obtained by ramp input test and static flow gains are alike each other. Two valves are about the same in dead bands and hysteresis characteristics.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.195-200
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• 2012

In this study, parameters and requirements of an 120kW class monorail planetary gearbox was analysed and the adaptive planetary gearbox design was selected. The specification of the sun gear, planetary gear and carrier was set and the profile & lead was optimized. The mechanical efficiency of the optimized one and the original one was observed. Dynamo-tester system was used to observe the mechanical efficiency of the planetary gearbox. A dynamo unit was connected with the planetary gearbox which straightened through the motor by a coupling. The standard tooth shape planetary gearbox and modified tooth shape planetary gearbox were used as test pieces and the rotation speed was set from 600 to 6000rpm with 600rpm, 2.5min one step. In order to check the mechanical efficiency of the planetary gearbox, the tests were done as follows. 1) The power loss between driving motor and dynamo tester. 2) Temperature variation by different rotation speeds. 3) Noise variation by different rotation speeds.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2189-2196
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• 2014

In this paper, a VLIW(Very Long Instruction Word) vision coprocessor which can efficiently accelerate computer vision algorithm for automotive is designed. The VLIW coprocessor executes four instructions per clock cycle via 8-stage pipelined structure and has 36 integer and floating-point instructions to accelerate computer vision algorithm for pedestrian detection. The processor has about 300-MHz operating frequency and about 210,900 gates under 45nm CMOS technology and its estimated performance is 1.2 GOPS(Giga Operations Per Second). The vision system composed of vision primitive engine and eight VLIW coprocessors can execute pedestrian detection at 25~29 frames per second(FPS). Because the VLIW coprocessor has high detection rate and loosely coupled interface with host processor, it can be efficiently applicable to a wide range of vision applications.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.