• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.147-154
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• 1999

This paper presents a procedure for the frequency-domain analysis of a non-proportionally damped structure subjected to stationary seismic loads and for the finding of proper damper locations through simple analysis procedure without iteration. The shear areas of the dampers are decided in proportion to the magnitude of the components of the primary mode shape vector and to the root mean square values of the story drifts, The root-mean-squear responses are obtained using a power spectral density function for the ground acceleration. the results are compared with those obtained from damper placement decided in sequency based on the maximum story drift. According to the results the reliability of the proposed method turns out to be satisfactory compared to the methods which required iteration.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1756-1759
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• 2015

웨어러블 디바이스의 등장과 여러종류의 센서탑재로 행위데이터를 수집하는것이 수월해졌다. 행위패턴 모델링에 앞서 사용자의 행위에따른 신호변화와 신호패턴을 파악하기위해 분석을 실시하였다. Moto360의 3축 가속도 센서를 이용 사용자에 행위에대한 센서신호값을 수집하여 행위에따른 신호값을 수집하였으며, 수집된 신호값과 신호값으로부터 SVM(Signal Vector Magnitude)값을 구해 사용자의 각 행위들에 대해 신호값과 SVM값의 특징을 분석하여 측정 신호값으로부터 행위를 인식할수 있도록 시도하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.103-108
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• 2005

Loading/Unloading task in the real industry is performed by crane, but most of the loading/unloading task with the weight of 5kg∼30kg is done by human workers and this kind of work causes industrial disaster of workers. Therefore it is necessary to develop low cost loading/unloading manipulator system to prevent this kind of industrial accidents. This paper is concerned with the design and fabrication of 2 axis pneumatic manipulators using on/off solenoid valves and accurate position control without respect to the external load and low damping in the pneumatic rotary actuator. To overcome the change of external load, switching of control parameter using LVQNN (Learning Vector Quantization Neural Network) is newly applied, which estimates the external loads in the pneumatic cylinder. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied to the switching control system. The effectiveness of the proposed control algorithms are demonstrated through experiments of pneumatic cylinder with various loads.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.530-533
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• 2011

방사형 그라디언트 페인트(radial gradient paint)는 벡터 그래픽스(vector graphics)에서 적은 정보로 다양한 효과를 적용시킬 수 있는 방법이다. 기본적으로 이 방법은 곱하기, 나누기, 제곱근 등의 복잡한 연산이 필요하기 때문에 모바일 같은 저성능 환경에 적합하지 않았다. 하지만 최근 모바일 기기들은 SIMD 연산 지원 및 고성능의 GPU 탑재 등으로 성능이 향상됨에 따라 이러한 문제를 해결할 수 있게 되었다. 본 논문은 ARM의 SIMD연산인 NEON을 이용하여 최대 2.6배의 성능을 가속시켰으며 GPU의 쉐이더를 이용하여 4.9배의 성능을 가속하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.4
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• pp.466-473
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• 2024

An Emergency Destruction System is inevitable for ensuring safety both at sea and in populated areas, particularly during emergency detonations triggered by abnormal missile flight or upon mission completion. This paper introduces a novel method for developing an Emergency Destruction System capable of precisely calculating the Instantaneous Impact Point(IIP) during high-speed, maneuverable long-range surface-to-air missile flight tests. The Emergency Destruction System designed for long-range surface-to-air missile flight tests generates impact position tables that meticulously incorporate wind errors and navigation equations based on the Earth's ellipsoidal model. Factors such as the Coriolis effect and the direction of the gravitational acceleration vector are accounted for, significantly enhancing the accuracy of IIP determination amidst highly variable missile speed and attitude.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.6
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• pp.1211-1216
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• 2002

To evaluate whole-body vibration(WBV) exposure and fatigue-decreased proficiency(FDP) boundary in passenger car driver, several roads in Busan were divided into 3 types by the condition of road surface; Road 1 was partially damaged, Road 2 was normal without damage, and Road 3 was better than Road 2. The results were following: The highest passenger driver's exposures to whole-body vibration acceleration and fatigue-decreased proficiency boundary at 40km/h were 0.108m/s² and about 2099 minutes in Road 2 for xh axis, 0.134m/s² and about 1585 minutes in Road 2 for yh axis, and 0.183m/s² and about 1053 minutes in Road 2 for zh axis, respectively. The highest passenger driver's exposures to whole-body vibration acceleration and fatigue-decreased proficiency boundary at 80km/h were 0.219m/s² and about 830 minutes in Road 3 xh axis, 0.203m/s² and about 918 minutes in Road 3 for yh axis, and 0.622m/s² and about 195 minutes in Road 1 for zh axis, respectively. The highest vector sums of whole-body vibration exposure at 40km/h and 804km/h were 0.328m/s² in Road 2 and 0.730m/s² in Road 1, respectively. The highest crest factors at 40km/h were 4.25 in Road 1 for xh, 4.51 in Road 3 for yh, and 5.81 in Road 2 for zh, respectively. The highest crest factors at 80km/h were 5.57 in Road 1 for xh, 5.60 in Road 2 for yh, and 6.46 in Road 3 for zh, respectively. The highest transmissibilities of whole-body vibration from floor to seat at 40km/h and 80km/h were 0.89 in Road 3 and 0.82 in Road 3 for xh axis, 0.83 in Road 3 and 0.87 in Road 1 and 2 for yh, and 0.80 in Road 2 and 0.92 in Road 1 tor zh axis, respectively. The highest fatigue-decreased proficiency boundaries for whole-body vibration exposure of passenger car driver in floor and seat were 457 minutes in Road 3 and 583 minutes in Road 3 at 40km/h and 159 minutes in Road 2 and 251 minutes in Road 2 at 80km/h, respectively.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.1-9
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• 2012

As we are turnning into the aged society, accidents by falling down are increasing in the aged people's group. In this paper, we design the system with the 3-Axis acceleration sensor which is composed by a single chip. The body activity signal is measured with the signal detector and RF communicator in this proposed system and the and falling by the entering signal pattern analysis with 3-Axis acceleration sensor. For the RF communication, we are using nRF24L01p and 8bits ATmega uC for the processor. The error of energy expenditure estimation between motor driven treadmill and proposed a body activity module was 7.8% respectively. Human activities and falling is monitored according to analyze and judge the critical value of the Signal Vector. as falled down if they don't turn off the alarm after specific period and the aged person's after falling down activities are their position and more.

• Journal of Biosystems Engineering
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• v.8 no.2
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• pp.26-38
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• 1983

Binder harvesters introduced to Korea were originally designed to be used for Japonica varieties which are highly resistant to shattering. In order to improve the performance of the binder to Indica varieties which are easily shattered and have shorter stem, mechanical modifications of the binder are inevitable. Shattering losses of the binder can be classified into two major parts; one incurred before and one after binding operations. The latter has been evaluated as great as the former. Previous studies indicated that the high discharge losses resulted from a great impact force of the discharge arm on the rice bundle during the discharge process. This study was intended to theoretically analyze the discharge mechanism of four-bar linkage. For this purpose, two commercially available binder harvesters having a four-bar linkage as a discharge mechanism were analyzed. Using the results from the motion analysis and the other structural constraints of the machines, they were modified and experimentally compared with the machines without modification to see whether any decrease in grain losses was obtained. The results obtained in this study are summarized as follows: 1. The path, velocity and acceleration of discharge arm were computer analyzed by vector analysis. Using results of the analysis and intrinsic constraints of the binder, discharge mechanism was modified to reduce the impact force on bundle by discharge arm in the range where the discharge performance was not deteriorated. This modification of the discharge mechanism could be done with an aid of four-bar linkage synthesis technique. As a result, average velocity and acceleration of the discharge arm during the discharge process were reduced respectively by 19 percent and 33 percent for binder A, and 17 percent and 35 percent for binder B. 2. Through the modification of the discharge mechanism, discharge losses of binder A were reduced by 42-56 percent for Milyang 23, Poongsan and Hangang chal, and discharge losses of binder B were reduced by 13-20 percent for Milyang 23 and Poongsan. 3. Discharge losses were decreased as the bundle size became larger and the size effect on the decrease rate appeared more significant in the binders with modifications than in those without modifications.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.6
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• pp.257-264
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• 2013

In this study, we have designed the variable amplitude threshold algorithm that can enhance the accuracy of step count using variable amplitude. This algorithm converts the x, y, z sensor values into a single energy value($E_t$) by using SVM(Signal Vector Magnitude) algorithm and can pick step count out over 99% of accuracy through the peak data detection algorithm and fixed peak threshold. To prove the results, We made the noise filtering with the fixed amplitude threshold from the amplitude of energy value that found out the detection error was increasing, and it's the key idea of the variable amplitude threshold that can be adapted on the continuous data evaluation. The experiment results shows that the variable amplitude threshold algorithm can improve the average step count accuracy up to 98.9% at 10 Hz sampling rate and 99.6% at 20Hz sampling rate.

• Smart Structures and Systems
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• v.17 no.3
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• pp.363-389
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• 2016

Deficient modes that cannot be always identified from different sets of measurement data may exist in the application of operational modal analysis such as the stochastic subspace identification techniques in large-scale civil structures. Based on a recent work using the long-term ambient vibration measurements from an instrumented cable-stayed bridge under different wind excitation conditions, a benchmark problem is launched by taking the same bridge as a test bed to further intensify the exploration of mode identifiability. For systematically assessing this benchmark problem, a recently developed SSI algorithm based on an alternative stabilization diagram and a hierarchical sifting process is extended and applied in this research to investigate several sets of known and blind monitoring data. The evaluation of delicately selected cases clearly distinguishes the effect of traffic excitation on the identifiability of the targeted deficient mode from the effect of wind excitation. An additional upper limit for the vertical acceleration amplitude at deck, mainly induced by the passing traffic, is subsequently suggested to supplement the previously determined lower limit for the wind speed. Careful inspection on the shape vector of the deficient mode under different excitation conditions leads to the postulation that this mode is actually induced by the motion of the central tower. The analysis incorporating the tower measurements solidly verifies this postulation by yielding the prevailing components at the tower locations in the extended mode shape vector. Moreover, it is also confirmed that this mode can be stably identified under all the circumstances with the addition of tower measurements. An important lesson learned from this discovery is that the problem of mode identifiability usually comes from the lack of proper measurements at the right locations.