• Journal of Electrical Engineering and Technology
• /
• 제10권5호
• /
• pp.2155-2161
• /
• 2015

This study suggests an optical method to measure cardinal of gait (step width, step length, and stride length) with position sensitive detector (PSD). The effect of reflector’s shape (flat and cylinder) on the PSD output voltage was examined for the application of the suggested system to real situations with a curved shape reflector (e.g. shoes). Various mathematical models were evaluated to find the optimal equation for the distance measurement. Considering the effect of shape on detected signal, the inverse polynomial model was developed. The suggested method is simple to operate, low in cost, small in size, and can evaluate gait parameters in real time. This method is expected to be useful in the field of rehabilitation and sport science

• 한국콘텐츠학회논문지
• /
• 제19권9호
• /
• pp.476-484
• /
• 2019

RFID 요킹증명은 한 쌍의 태그가 동시에 스캔 되었는지를 증명한다. 단일 리더에 의해 동시에 스캔 된 태그들은 서로 인접해 있기 때문에, 요킹증명은 태그가 부착된 객체들의 물리적 인접성을 검사해야 하는 응용에서 사용된다. 현재까지 제안된 대부분의 요킹증명 기법들은 인접한 태그에 관한 사전정보가 필수적이다. 만약 인접한 태그에 관한 정보를 수집하는 과정에서 오류가 발생하면, 이후의 증명들은 모두 검증에 실패하게 된다. 그러나 현재까지 인접한 태그에 관한 정보를 얻기 위한 구체적인 방법을 제시한 연구는 아직 없다. 이 연구에서 나는 요킹증명 기법을 위한 인접태그 정보 획득 기법인 TPIA을 제안한다. 제안기법은 스캐닝영역 결정과 스캐닝영역 검증의 두 단계로 구성된다. 스캐닝영역 결정 단계에서는 태그들의 위치와 전송범위를 고려하여 태그들을 스캔할 영역의 크기와 위치를 결정하며, 스캐닝영역 검증 단계에서는 고정된 위치의 참조태그를 사용하여 태그 스캐닝이 스캐닝영역 안에서 수행되었는지 여부를 검증한다. 나는 분석에서 제안하는 스캐닝영역이 정상적인 인접태그 정보의 획득을 보장하며, 스캐닝영역 검증이 스캐닝영역의 변형과 이탈을 감지하는 것을 보인다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1951-1956
• /
• 2008

Various MEMS accelerometers are used in engineering applications including automobiles, mobile phones, military systems, and electronic devices. Among them, the thermal accelerometer employing the temperature difference induced by the convective flow inside the micro cavity has been a topic of interest. As the convective sensor does not utilize a solid proof mass, it is compact, lightweight, inexpensive to manufacture, sensitive and highly endurable to mechanical shock. However, the complexity of the convective flow and various design constraints make optimization of a device a crucial step before fabrication. In this work, optimization of a 2-axis thermal convective MEMS accelerometer is conducted based on 3-dimensional numerical simulation. Parametric studies are performed by varying the several design variables such as the heater shape/size, the cavity size and types of the gas medium and the position of temperature probes in the sensor. The results of optimal design are presented.

• 한국전기전자재료학회논문지
• /
• 제18권11호
• /
• pp.1001-1006
• /
• 2005

A new fabrication method is proposed to form the stacked polysilicon gate by nitridation in $N_2$ atmosphere using conventional LP-CVD system. Two step stacked layers with an amorphous layer on top of a polycrystalline layer as well as three step stacked layers with polycrystalline films were fabricated using the proposed method. SIMS profile showed that the proposed method would successfully create the nitrogen-rich layers between the stacked polysilicon layers, thus resulting in effective retardation of dopant diffusion. It was observed that the dopants in stacked films were piled-up at the interface. TEM image also showed clear distinction of stacked layers, their plane grain size and grain mismatch at interface layers. Therefore, the number of stacked polysilicon layers with different crystalline structures, interface position and crystal phase can be easily controlled to improve the device performance and reliability without any negative effects in nano-scale CMOSFETs.

• 한국운동역학회지
• /
• 제20권3호
• /
• pp.327-336
• /
• 2010

The purpose of this study was to analyze muscle activities on functional insole with diet effect. Originally, ten healthy female subjects with an average age of 23.2 year(S.D=1.1), weight of 49.7 kg(S.D=4.9), height of 163.2 cm(S.D=3.5) and a shoe size of 237.5 cm(S.D=4.9) were participated in this experiment. Ten healthy females walked on a treadmill(speed=about 4.2 km/h) wearing two different insole types. Muscle activities data was collected using the EMG operating system. The surface EMG signal for tibialis anterior(TA), gastrocnemius(GA), vatus lateralis(VL) and biceps femoris(BF) were acquired at the RMS(10 Hz, 350 Hz) using Noraxon Telemyo DTS system(Noraxon inc, USA). This study processed the data using the Windows SPSS ver.17.0 to get an independent t-test, with the setting, p<.05. Analysis of muscle activity were measured and calculated during walking. The results are as follow: Functional insole wearing were increased muscle activities significantly from Tibialis anterior(TA) during total gait cycle. Normal distribution was demonstrated in total step of stances period. One foot standing position showed decreased muscle activity. Two foot standing position was demonstrated with gastrocnemius and biceps femoris. As a result of the analysis, Functional insole will inerease the diet effect in the use of four muscle groups.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.1720-1723
• /
• 2000

Boron doped conducting diamond thin film were grown on Si substrate by microwave plasma chemical vapor deposition from a gaseous feed of hydrogen, acetone/methanol and solid boron. The doping level of boron was controlled from 0ppm to $10^4$ppm (B/C). The Si substrate was tilted ca. 10$^{\circ}$ to make Si substrate have different height and temperature. Experimental results show that same condition but different temperature of Si substrate by height made different crystalline of diamond thin film. There were appeared 3$\sim$4 step of different crystalline morphology of diamond. To characterize the boron-doped diamond thin film, Raman spectroscopy was used for identification of crystallinity. To survey surface morphology, microscope was used. Grain size was changed gradually by different temperature due to different height. The Raman spectrum of film exhibited a sharp peak at 1334$cm^{-1}$, which is characteristic of crystalline diamond. The lower position of diamond film position, the more non-diamond component peak appeared near 1550$cm^{-1}$.

• Journal of Positioning, Navigation, and Timing
• /
• 제8권2호
• /
• pp.49-58
• /
• 2019

A number of techniques have been studied to estimate the position of pedestrians in indoor space. Among them, the technique of estimating the position using only the sensors attached to the body of the pedestrian without using the infrastructure is regarded as a very important technology for special purpose pedestrians such as the firefighters. In particular, it forms a research field under the name of Pedestrian Dead Reckoning (PDR). In this paper, we focus on a method for step detection which is essential when performing PDR using Inertial Measurement Unit (IMU) mounted on a shoe. Many researches have been done to detect the stance phase where the foot contacts the ground. Most of these methods, however, have a way to detect the specific size of the sensor signal and require thresholds for these methods. This has the difficulty of changing these thresholds if the user is different. To solve this problem, we propose a stance phase detection method that does not require any threshold value. It is expected that this result will make it easier to commercialize the technology because PDR can be implemented without user-dependent parameter setting.

• 대한기계학회논문집A
• /
• 제39권4호
• /
• pp.415-421
• /
• 2015

본 연구는 햅틱 진동자의 개발과정에 있어 성능인자의 단계별 설정절차와 성능 및 소형화를 위한 자석의 착자방법에 대한 연구를 수행하였다. 착자방법에 대한 연구는 수평착자와 수직착자의 구성방법에 따른 전자기력을 비교분석하여 수행하였으며, 수행결과 수평착자가 우수한 것으로 나타났다. 시스템적 설계 절차로는 제품의 특성으로부터 설계 인자를 설정하는 단계적 절차를 구성하여 시작품을 제작하고 시험을 통하여 검증하였다. 해석적 방법에서는 진동응답 특성 해석과 전기장의 해석을 독립적으로 수행하였으며, 시험결과와의 검증을 통해 잘 일치하는 결과를 도출하였다. 제품신뢰성 확보를 위한 신뢰성 기반 설계인자는 스프링 높이, 용접 위치, 코일의 위치로 선정하였다. 그리고 설계 인자에 따른 전자기장 민감도 및 성능 변화를 분석하였고 이를 바탕으로 신뢰성 기반의 고성능 햅틱 진동자를 구현할 수 있도록 설계방법을 제시하였다.

• 한국정밀공학회지
• /
• 제19권11호
• /
• pp.211-220
• /
• 2002

Optical disk drives read information by replacing a laser beam on the disk track. As information has become larger, the more accurate position control of a laser beam is necessary. In this paper, we report the analysis and fabrication of the micro mirror for optical disk drivers. A coupled simulation of gas flow and structural displacement of the micro mirror using the Finite-Element-Method is applied to this. The mirror was fabricated by using MEMS technology. Especially, the process using the lapping and polishing step after the bonding of the mirror and electrode plates was employed for the Process reliability. The mirror size was 2.5mm${\times}$3mm and it needed about 35V for displacement of 3.2 ${\mu}$.

• 한국정밀공학회지
• /
• 제17권3호
• /
• pp.174-183
• /
• 2000

Non-Parallelism the axial direction occurs during grinding process of long slender shafts. The reason for the axial error is due to elastic deformation of the components, accumulation phenomenon of the grinding and wheel wear during the grinding process. The accumulation phenomenon, the size generation mechanism and the wheel wear process during traverse grinding result in complicated process at each step on the wheel surface. The grinding system stiffness obtained from the stiffness of the center on the tailstock and the workpiece varing according to the relative position of the wheel and the workpiece. Further more, the value of wheel wear increases as the grinding process advances. The above mentioned issues make the shape generation process during traverse grinding quite complicated. This research analyzes the shape generation process in the direction of the work spindle. First, the formulation of the grinding system stiffness was conducted and the simulation analysis method of the traverse grinding was established. Also, a measuring system for assessing the dimensinal accuracy of the workpiece has been developed.