• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3357-3362
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• 2014

The purpose of this research was to develop a resonance electric power generator to harvest vibration energy while the vehicle is driving on a road surface. The electric power generator in the paper was designed using the resonance phenomenon to effectively respond to vibrations from the road surface, which is a comparatively small energy source. Vibration displacement analysis using MATLAB and transient analysis using Ansys MAXWELL, which is a commercial electromagnetic analysis program, was performed to predict the input velocity for the generator and verify the electric power generation. If this electric power generator is applicable to hybrid or electric vehicles, it can be valuable around an automotive electric system and help maintain the performance of the vehicle battery.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.789-795
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• 2010

For the reliable clamping of a robotic colonoscope inside the colon, we propose a clamping module consisting of six legs at the front and a trigger at the rear. In addition, a pneumatic-line based locomotive mechanism, which was developed previously for in-pipe inspection, is adopted to reduce the friction force between the pneumatic lines and the locomotion environment. In order to evaluate locomotion performance, a robot with a diameter of 15 mm and a length of 110.250 mm is used. Based on control signal from LabVIEW, it is tested in acrylic pipe and pig's colon. The proposed robot is able to move in the curved path which has a radius of over 25 mm. The speed of the robot is 33 mm/s in a straight path and 12.1 mm/s on a vertical path. The proposed robot, which has one pneumatic line and two clamping modules, conclusively shows reliable locomotion performance under in vitro condition.

• Journal of the HCI Society of Korea
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• v.1 no.1
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• pp.29-36
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• 2006

Tactile displays can provide useful information without disturbing others and are particularly useful for people with visual or auditory impairments. They can also complement other displays. In this paper, we present a new vibrotactile display device for wearable, mobile, and ubiquitous computing environments. The proposed vibrotactile device has a $5{\times}5$ array configuration for displaying complex information such as letters, numbers, and haptic patterns as well as simple directional ques and situation awareness alarms. Commercially available coin-type vibration motors are embedded vertically in flexible mounting pads in order to best localize vibrations on the skin. An embedded microprocessor controls the motors sequentially with an advanced tracing mode to increase recognition rate. User studies with the vibrotactile device on the top of the foot show 86.7% recognition rate for alphabet characters after some training. In addition, applying vibrotactile device to driving situation shows 83.9% recognition rate. We also propose some potentially useful application scenarios including Caller Identification for mobile phones and Navigation Aids for GPS systems while driving.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.19-27
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• 2015

As the recent regulation of Internaional Maritime Organization (IMO) is enforced, the advanced technology of Ballast water treatment system (BWTS) is needed to meet its requirements. Until now, there are two kinds of the BWTS technologies such as physical methods (Membrane and UV) and chemical methods (Chlorin and Ozone). However, these conventional methods have some limitations of auxiliary power, low productivity, residual treatment and etc. In order to overcome these problems, this paper introduces the new kind of BWTS based on mechanical principle and investigates the effect of rotating disc shapes on flow characteristics between rotating and stationary discs by computational fluid dynamics (CFD). Planar and Step types can make the local cavitation generated along radius, and Circular type can increase the intensity of shear stress.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.351-359
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• 2012

This paper deals with the design and development of the remote control and measurement systems using CDMA(Code Division Multiple Access) data modem. We propose a bi-directional data communication link without the public IP address in CDMA modem device by the TCP/IP packet and SMS(Short Message Service) communication. The remote control and measurement systems are implemented by a Telit WM-800 modem as DCE(Data Communication Equipment), and Atmel AT89C51 microcontroller as DTE(Data Terminal Equipment). The user application software for the control and measurement system user, and the firmware software of device drivers for peripherals such as a digital input/output device, AD/DAC(Analog to Digital/Digital to Analog Converter), LCD, and temperature/humidity sensor are written in Microsoft C and Keil C language respectively for further various applications. The experimental result of the proposed control and measurement systems implemented in this paper is evaluated via real-time experiments, which works well as designed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.1
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• pp.59-65
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• 2013

In recent years, the crisis of energy is growing seriously and also the contamination of ecology has been reverberated as international problem. The social concerns on energy crisis have been growing for the last several years and also the interests in new and renewable energy have been increased. Therefore, in order to solving these problems, as solution of one, this paper is investigated using the aeration system at the fish farm, etc from nature energy such as wind power. This study suggests the fundamental data of designing for these similar apparatus and examines the parameters of wind velocity and wind receiving area. Especially, the water outlet position was mainly investigated with optimum outlet angle of wind pump.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.440-447
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• 2017

Spectrum level for the acoustic roughness of wheels and rail surface should be periodically maintained under the limitation of ISO to reduce rolling noise of railway vehicles. Thus, in maintaining railway track, displacement sensor-based measuring devices are broadly used to measure the surface roughness and to perform spectral analysis. However, these measuring devices cause unexpected measuring errors since the displacement sensors are fixed at moving platforms and the main frame produces pitching motion during measurement. To increase the accuracy of the measured values, this paper has investigated the effects of design variables such as wheel base, additional wheels, and elastic deformation of wheels on the surface roughness and acoustic roughness spectrum.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.531-537
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• 2015

In order to maximize power output from the solar panels, one needs to keep the panels aligned with the sun. So solar tracker having high reliability must be designed. This paper cares about the design and evaluation of a two-axis solar tracker system based on fuzzy logic control with LabVIEW. The research focus on planning mechanical parts, making an intelligent controller which controls and monitors all parameters via user interface implemented of a fuzzy decision support system for control of photovoltaic panel movement. We also develop a real solar tracker system and analyze the influence indexes such as environment, weather, season, and light condition. The solar tracker is tested in real condition and all parameters related to the system operation are recorded and analyzed. The developed solar tracking system got a much higher efficiency about 38 % compare to fixed solar panel although the weather condition is affected a lot to the solar panel. So we confirmed the our auto tracking system is more effective and can allow more energy to be produced.

• Journal of the Korean Magnetics Society
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• v.9 no.2
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• pp.121-126
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• 1999

This paper describes a fabrication of Fe-dispersed hydrophilic magnetic fluid and its application to oil seal in combination with the Nd-permanent magnet. The results are as follows; 1) Using silica coated iron particle of magnetization of 125.5 emu/g (at 10 kOe) and the mean particle size of 100 $\AA$, after multiple adsorption to the surface of silica coated iron particle with oleic acid ion, D.B.S. and T.M.A. ion, hydrophilic Fe-magnetic fluid [70 %(g/∝)Fe, magnetization of 52 emu/g and viscosity of 1450 cp] can be produced by dispersing the iron particle in ethylene glycol solution. 2) The oil seal apparatus consisting of six stages of Nd-permanent magnet (3200 Gauss) and Fe-magnetic fluid [70 %(g/∝) Fe] showed an excellent pressure resistance of 7400 g/$\textrm{cm}^2$ under the gap between shaft and oil seal was 0.2 mm.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.33.3-33.3
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• 2010

17세기 이후 조선과 일본은 서로 다른 시각법을 사용하였다. 일본의 경우 서양의 자명종을 받아 들여 12시(時) 100각법(刻法)의 부정시법을 기초로 한 일식시계(和時計)인 자명종을 제작 발전시켰다. 이러한 자명종의 제작기술이 조선에 유입되었지만 조선과 일본의 시각법의 차이로 인해 정확한 기계시계임에도 불구하고 널리 보급되지 못했다. 현재 한국의 대표적인 자명종 유물은 고려대학교 박물관과 서울대학교 박물관에 소장되어 있다. 고려대학교 자명종의 경우 12시 96각법을 기준으로 하여 자명종 전면에 원형으로 12시와 1시진(時辰)에 8각(현행 1시간당 4각)으로 각인되어 있고, 그 밑 부분에 "구(九)", "팔(八)", "칠(七)", "육(六)", "오(五)", "사(四)"가 2회 반복하여 각인되어 있다. 타종장치는 파손되어 있고 구조와 형태로 봤을 때 일정한 시간에 한번 종을 치는 일정천부방식(一挺天符方式, Foliout) 자명종이다. 서울대학교 자명종은 시반에 12시와 숫자만 표기되어 있다. 이 자명종은 "구(九)", "팔(八)", "칠(七)", "육(六)", "오(五)", "사(四)"의 숫자 표기가 고려대학교 자명종과 일본 자명종 유물과는 다르게 반대의 방향으로 표기되어 있다. 이 자명종의 타종장치는 정해진 시각에 해당 시각만큼 타종하는 장치가 달린 이정천부방식(二挺天符方式) 자명종 형식이다. 서울대학교 자명종의 경우 일부 부품이 유실되고 개조된 것으로 보이며, 야간용 천부(天符)와 알람장치가 유실된 상태이다. 이는 일본의 부정시법 자명종을 조선의 정시법로 사용하기 위해서 개조한 것으로 여겨진다. 수차례에 걸친 국내와 일본의 학술조사를 수행하여 당시의 조선과 일본의 시각법에 대한 비교조사와 유물 및 문헌을 통해서 두 자명종의 구동방식을 알게 되었다. 또한 일본의 자명종 제작 기술 발달 과정과 비교하여 두 자명종의 제작시기 등을 추정하였다. 아울러 두 자명종의 파손된 부분에 대한 구조를 연구하여 기계적 작동원리에 대한 개념도를 제시하고자 한다.