• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.169-172
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• 2010

유비쿼터스 화재 방재 시스템은 온도, 습도, 조도, 가속도, CO2, 등의 다양한 센서로부터 얻는 값을 이용해 화재를 판별하여 관리자에게 전달하고 시스템 설정 값에 따라 소화설비를 동작시키는 지능형 화재 탐지 시스템이다. 기존 화재 판별 기법은 크게 영상인식, 퍼지추론, 베이지안 추론으로 나뉠 수 있다. 본 논문에서는 앞선 기술들을 분석하고, ARM9 S3C2440/SHT-75를 이용한 센서기반 유비쿼터스 화재 방재 시스템 최적의 화재 판별 기술로서 가속도 알고리즘과 벡터 랜덤변수 표본공간 영역을 이용한 패턴인식 기술을 사용한 복합 화재 판별 방법을 제안한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.8
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• pp.1165-1171
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• 2022

Human behavior recognition using an accelerometer has been applied to various fields. As smartphones have become used commonly, a method for human behavior recognition using the acceleration sensor built into the smartphone is being studied. In the case of the elderly, falling often leads to serious injuries, and falls are one of the major causes of accidents at construction fields. In this article, we proposed recognition method for human falling direction using built-in acceleration sensor and orientation sensor in the smartphone. In the past, it was a common method to use the magnitude of the acceleration vector to recognize human behavior. These days, deep learning has been actively studied and applied to various areas. In this article, we propose a method for recognizing the direction of human falling by applying the deep learning multilayer technique, which has been widely used recently.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.9
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• pp.783-790
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• 2016

One of the main factors related to the deterioration of estimation accuracy in inertial measurement unit (IMU)-based orientation determination is the object's acceleration. This is because accelerometer signals under accelerated motion conditions cannot be longer reference vectors along the vertical axis. In order to deal with this issue, some orientation estimation algorithms adopt acceleration-compensating mechanisms. Such mechanisms include the simple switching techniques, mechanisms with adaptive estimation of acceleration, and acceleration model-based mechanisms. This paper compares these three mechanisms in terms of estimation accuracy. From experimental results under accelerated dynamic conditions, the following can be concluded. (1) A compensating mechanism is essential for an estimation algorithm to maintain accuracy under accelerated conditions. (2) Although the simple switching mechanism is effective to some extent, the other two mechanisms showed much higher accuracies, particularly when test conditions were severe.

• Journal of Internet Computing and Services
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• v.11 no.1
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• pp.129-141
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• 2010

In this paper, we present a wearable intelligent device based on multi-sensor for monitoring human activity. In order to recognize multiple activities, we developed activity recognition algorithms utilizing an image sensor and a 3-axis accelerometer sensor. We proposed a grid?based optical flow method and used a SVM classifier to analyze data acquired from multi-sensor. We used the direction and the magnitude of motion vectors extracted from the image sensor. We computed the correlation between axes and the magnitude of the FFT with data extracted from the 3-axis accelerometer sensor. In the experimental results, we showed that the accuracy of activity recognition based on the only image sensor, the only 3-axis accelerometer sensor, and the proposed multi-sensor method was 55.57%, 89.97%, and 89.97% respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.3
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• pp.8-16
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• 2002

The implicit formulation of rotor dynamics for helicopter flight simulation has been derived and and presented. The generalized vector kinematics regarding the relative motion between coordinates were expressed as a unified matrix operation and applied to get the inertial velocities and accelerations at arbitaty rotor blade span position. Based on these results the rotor aeromechanic equations for flapping dynamics, lead-lag dynamics and torque dynamics were formulated as an implicit form. Spatial integration methods of rotor dynamic equations along blade span and the expanded applicability of the present implicit formulations for arbitrary hings geometry and hinge sequences have been investigated. Time integration methods for present DAE(Differential Algebraic Equation) to calculate dynamic response calculation are recommenaded as future works.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.992-1002
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• 1988

The dynamic response of rotor-bearing systems subjected to six-component nonststionary earthquake ground accelerations is analyzed. The governing equations of motion for the rotor are derived using Lagrangian approach. The six-component earthquake inputs result in both inhomogeneous and parametric excitations, so that the conventional spectral analysis of random vibration is not applicable. The method of Monte Carlo simulation is utilized to simulate the six-component nonstationary earthquake ground motions and to determine the response statistics of rotor-bearing systems. The significant influences due to rotational motions of seismic base on the overall structural response is demonstrated by a numerical example.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.82-85
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• 2010

MPSoC 는 하나의 칩 안에 여러 개의 프로세서와 이를 뒷받침 하는 다수/다량의 메모리 시스템, 인터페이스, 그리고 그 밖의 여러 IP 등을 탑재하는 기술을 말하며, 본 논문에서는 이종의 EISC 프로세서, DSP 프로세서와 2D 벡터 그래픽 가속기를 이용하여 4 개의 프로세서로 구성된 이종 MPSoC를 설계하였다. 설계한 이종 MPSoC 는 Global Foundies 0.13um MPW 공정으로 구현하였으며, 테스트 보드 상에서 2D 벡터 그래픽 가속기와 DSP 프로세서를 이용한 이미지 처리 및 오디오 재생을 통하여 동작을 검증하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.1_2
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• pp.135-143
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• 2004

3D Graphics accelerator is usually composed of two parts, geometry engine and rasterizer. In this paper, VGE(Vector Geometry Engine) which exploits vertex-level parallelism is proposed. In VGE, Common Floating-Point Unit by adding four-FADD, four-FMUL unit and 128-vector register accelerates geometry calculation. In comparison with SH4, Performance result show that the VGE can achieve performance gain over 4.7 times. To evaluate VGE performance, we make simulator to rebuild Simple-Scalar, general purpose processor simulator. In simulator model, we use Viewperf-benchmark.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.534-542
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• 2005

This paper proposes the fuzzy logic based vector control method for a Surface Mounted Permanent Magnet Synchronous Motor(SMPMSM) used in the elevators. The gain of a conventional PI speed controller in the elevator drive system can not be usually set high due to mechanical resonances, therefore its performance becomes deteriorated. There have been many methods to solve above problems such as an acceleration feedback in the speed controller. However, the above methods have defects that parameter information is demanded. In this paper', a Fuzzy controller(FC) is adopted in the elevator drive system. The performance of a fuzzy controller is compared with a PI controller in the no load and load conditions by simulation and experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.6
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• pp.393-400
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• 2022

The Divert and Attitude Control System(DACS) used in high-altitude engagements is expensive and complex. In this paper, we design a high-altitude terminal guidance and control loop of guided-missile equipped with a Thrust Vector Control(TVC) that is less expensive and simpler than DACS. The proposed system utilizes a quaternion feedback control technique to track the thrust attitude command converted from the acceleration command of true proportional navigation guidance. The performance analysis of the proposed terminal guidance and control loop is conducted through engagement simulations against ballistic targets at a high altitude.