• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.7-11
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• 2004

일상생활과 산업현장에서 측정되는 힘의 범위를 정리해 보면 Fig. 1 과 같다. 힘의 SI 단위인 1뉴턴(N : 단위 질량 1 kg에 대해 1$m/s^2$ 의 가속도를 생기게 하는 힘의 크기임 정성적으로는 사과 반쪽을 손에 들고 있을 때 느끼는 중력의 크기가 약 1 N임)을 기준으로 크게는 수십 MN($10^{6}$ N) 크기의 우주선에서 발생하는 추진력에서부터 작게는 수 PN($10^{-12}$ N) 크기의 원자들 사이의 결합력까지 그 범위가 매우 광범위하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1185-1187
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• 2011

이 논문에서는 운전자의 운전 패턴을 분석하기 위한 멀티 센서 기반의 패턴 분석 알고리즘을 제안한다. 센서를 통해 얻어진 주행 데이터의 상관 관계를 비교, 분석하여 주행 패턴을 인식한다. 가속도 센서에 작용하는 중력값과 지자기 센서의 방향 데이터을 통해 각 운전 패턴을 인식하는 정확도를 높이는데 이용하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.11
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• pp.965-972
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• 2016

This paper presents results of flight experiments on a navigation algorithm including multiplicative extended Kalman filter for estimating attitude of the guided munition. The filter describes orientation of aircraft by data fusion with low-cost sensors where measurement update is done by multiplication, rather than addition, which is suitable for quaternion representation. In determining attitude from vector observations, the existing approach utilizes a 3-axis accelerometer as a 2-axis inclinometer by measuring gravity to estimate pitch and roll angles, while GNSS velocity is used to derive heading of the vehicle. However, during accelerated maneuvers such as coordinated flight, the accelerometer provides inadequate inclinometer measurements. In this paper, the measurement update process is newly defined to complement the vulnerability by using different vector observations. The acceleration measurement is considered as a result of a centrifugal force and gravity during turning maneuvers and used to estimate roll angle. The effectiveness of the proposed method is verified through flight experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2318-2324
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• 2017

Quantum cryptography, which is emerging as a next generation password, is being studied by quantum cryptographic transfer protocols and quantum secret communication. Quantum key transfer protocol can be used in combination with the modern password because of the inefficiency of the use of the password, or the use of OTP(one time password). In this paper an algorithm for direct communication by means of direct cryptographic communications rather than quantum keys. The method of implementing quantum secure direct community was adopted using 2-channel methods using Einstein gravity field. Two channels were designed to adopt a quantum secret communication protocol that applies time delay between 2-channels of channel to apply time difference between 2-channels. The proposed time delay effect reflects the time delay by reflecting the gravitational lensing phenomenon. Gravity generator with centrifugal acceleration is incorporated in the viscometer, and the time delay using this implies the correlation between the variance of the metametry.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.4
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• pp.271-274
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• 2013

Inclinometer sensors are widely applied in many fields. Especially in the field of construction of high-rise buildings also measure the horizontal and vertical help has been applied to monitor. Recent micro electro-mechanical system(MEMS) technology with the development of the many sensors have been developed. In this paper, a MEMS inclinometer is based on a MEMS accelerometer. The sensor can measure the angle of inclination using the relationship between static acceleration and gravity acceleration from an accelerometer. From this principle, inclinometer has been developed that has more accurate. The accuracy is proved by the experiment with laser displacement. Results in the experiment express high-accuracy, stability and economics of MEMS inclinometer. In conclusion, wireless MEMS inclinometer sensor is expected to be applicable in the areas of construction and many other industries with accurate and convenient monitoring system.

• Journal of the Korean Geotechnical Society
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• v.29 no.3
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• pp.29-40
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• 2013

Seismic response of single degree of freedom system supported by shallow foundation was analyzed by using nonlinear explicit finite difference element code. Numerical analysis results were verified with dynamic centrifuge test results of the same soil profile and structural dimensions with the numerical analysis model at a centrifugal acceleration of 20 g. Differences between the analysis and the test results induced by the boundary conditions of control points can be reduced by adding additional local damping to the natural born cyclic hysteretic damping of the soil strata. The analysis results show good agreement with the test results in terms of both time histories and response spectra. Thus, it can be concluded that the nonlinear explicit finite difference element code will be a useful technique for estimating seismic residual displacement, earthpressure etc. which are difficult to measure during laboratory tests and real earthquake.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.11
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• pp.921-933
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• 2018

There is a method to enhance the pure navigation performance of INS(Inertial Navigation System) through the rotation of inertial measurement unit to compensate error sources of inertial sensors each other and that INS using this principle of operation is called rotational INS. In this paper, the exact error analysis of rotational INS based on ring laser gyro considering the coupling effect with gravity and earth rate is performed to evaluate the navigation performance by inertial sensor error sources. And error analysis and performance evaluation result confirmed by modelling and simulation is also proposed in this paper.

• Journal of Korea Multimedia Society
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• v.16 no.1
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• pp.67-74
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• 2013

In this paper, we propose the pointing and correction algorithm for optimized performance based on Bluetooth communication. The error from the accelerometer sensor's output must be carefully managed as the accelerometer sensor is more sensitive to data change compared to that of the gyroscope sensor. Thus, we minimize the noise by applying the Kalman filter to data for each axis from the accelerometer. In addition, we can also obtain effect compensating the hand tremor by applying the Kalman filter to the data variation for x and y. In this study, we extract data through the Quaternion mapping process on data from the accelerometer and gyroscope. In turn, we can obtain a tilt compensation by applying a compensation algorithm with acceleration of the gravity of the extracted data. Moreover, in order to correct the inaccuracy on smart sensor due to the rapid movement of a device, we propose a adaptive pointing and correction algorithm using the genetic approach to generate the initial population depending on the user.

• Progress in Medical Physics
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• v.24 no.1
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• pp.61-67
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• 2013

In this study, we developed and evaluated the patient respiration training method which can help to avoid the problems for the limitation of RGRT applicable patient cases. By using the MEMS (micro-electro-mechanical-system) acceleration sensor, we measured movement of motion phantom. We had compared the response of MEMS with commercially introduced real time patient monitoring (RPM) system. We measured the response of the MEMS with 1 dimensional motion phantom movement for 2.5, 3.0, 3.5 second of period and the 2.0, 3.0, 4.0 cm of the amplitudes. The measured period error of the MEMS system was 0.6~6.0% compared with measured period using RPM system. We found that the shape of MEMS signals were similar with RPM system. From this study, we found the possibility of MEMS as patient training system.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.111.2-111.2
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• 2010

삼상슬러리 기포탑 반응기의 설계 및 Scale-up을 위하여 기포탑의 직경변화에 따른 기체-슬러리 계면에서의 물질전달 현상의 Similarity를 검토하고, 기체-슬러리 계면에서의 물질전달 현상과 슬러리 기포탑 반응기의 운전변수 및 반응물들의 물성들과의 연관성을 고찰하기 위하여 삼상슬러리 기포탑의 물질전달계(System)에서 주요 파라메타를 도출하였으며, 이들 파라메터들을 이용하여 슬러리 기포탑반응기의 물질전달 Scaling을 검토하였다. 물질전달계의 주요제어인자로는 기체-액체 부피물질전달계수($k_La$), 슬러리상의 확산도($D_{SL}$), 기포탑의 직경(D), 기포탑 반응기에 유입되는 기체의 유입속도($U_G$), 기포탑 반응기 내부의 연속상인 슬러리상의 표면장력(${\sigma}_{SL}$), 슬러리상과 기체상간의 밀도차(${\rho}_{SL}-{\rho}_G$) 그리고 슬러리상의 점도(${\mu}_{SL}$)등 슬러리 상의 물성을 선정하였으며 중력가속도(g)를 선정하였다. 물질전달계의 Scling을 검토하기위하여 이를 재구성하였으며 기포탑 반응기의 구조와 직경이 변화함에 따라 이들 무차원군의 변화양상을 고찰하였다. 실험적으로 측정된 물질전달계수와 Scaling에 의해 예측된 물질전달계수를 비교 검토함으로써 본 연구의 Correlation의 적용범위를 제시하였다.