• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.128-136
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• 2003

In today's design trend of vehicle structure, crush zone is fiequently reinforced by adding a box-shaped sub-frame in order to avoid an excessive deformation against a high-speed offset barrier such as EU Directive 96/97 EC, IIHS offset test. That kind of vehicle structure design results in a relatively monotonic crash pulse for airbag ECU(Electronic Control Unit) located at non-crush zone. As for an angular crash event, the measured crash signal using a single-axis accelerometer in a longitudinal direction is usually weaker than that of frontal barrier crash. Therefore, it is not so easy task to achieve a satisfactory crash discrimination performance for offset and angular crash events. In this paper, we introduce a new crash discrimination algorithm using an electronic X-Y 2-axis accelerometer in order to improve crash discrimination performance especially for those crash events. The proposed method uses a crash signal in lateral direction(Y-axis) as well as in longitudinal direction(X-axis). A crash severity measure obtained from Y-axis acceleration is used to improve the discrimination between fire and no-fire events. The result obtained by the proposed measure is logically ORed with an existing algorithm block using X-axis crash signal. Simulation and pulse injection test have been conducted to verify the performance of proposed algorithm by using real crash data of a 2,000cc passenger vehicle.

• Archives of Plastic Surgery
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• v.43 no.1
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• pp.32-37
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• 2016

Background We conducted this study to analyze the values of the key cephalometric angular measurements of the mandible using 3-dimensional (3D) computed tomography scans. Methods In the 106 enrolled patients, a 3D cephalometric analysis was performed to measure the angular variables of the mandible. These values were compared between the two sides and between the two sexes. Results The frontal measurements revealed that the mandibular body curve angle was larger on the left (Lt) side (right [Rt], $141.24{\pm}7.54$; Lt, $142.68{\pm}6.94$; P=0.002) and the gonial angle was larger on the right side (Rt, $134.37{\pm}8.44$; Lt, $131.54{\pm}7.14$; P<0.001). The sagittal measurements showed that the gonial angle was larger on the right side (Rt, $134.37{\pm}8.44$; Lt, $131.54{\pm}7.14$; P>0.05). Further, the transverse measurements revealed that the mandibular body curve angle was larger on the right side (Rt, $140.28{\pm}7.05$; Lt, $137.56{\pm}6.23$; P<0.001). Conclusions These results provide an average of the mandibular angular measurements for the Korean population, establishing a standard for determining surgical patient groups and outcome evaluations in the field of mandible contour surgery.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.101-104
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• 2004

This paper addresses uncertainty issues encountered recently in measuring head vibration using the conventional 6-axis or 9-axis bite-bar Those conventional bite-bars are shown to present insufficient information to measure a complete 6 degree-of-freedom motion of head vibration. In order to overcome such limit, a theoretical measurement model that consists of four 3-axis linear accelerometers is suggested (Theoretical backgrounds presented in this paper shall have been addressed in the international congress of ICA 2004 in this April). It is shown to enable the direct measurement of three angular acceleration components and six angular velocity-dependent nonlinear terms. In audition to the three linear acceleration terms, those nine angular motion-dependent ones are found to make it possible to evaluate the general head vibration for a given position. To examine the feasibility of the proposed method, a newly designed 12-axis bite-bar was developed. Detailed experimental results obtained using the developed 12-axis bite-bar are illustrated in the presentation of this paper, which illustrates what amount of measurement accuracy provides. But, this paper provides more detailed experimental data and extended uncertainty factors.

• Journal of The Korean Astronomical Society
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• v.40 no.4
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• pp.131-132
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• 2007

The research of OH maser emission sources with high angular resolution is complicated by the effects of interstellar scattering: more over, most of the OH maser sources are located in the galactic plane where the scattering is largest. However, the data available from pulsar studies on the spatial distribution of the amount of scattering indicate that there is a strong non-uniformity in the distribution of the amount of scattering material. There are directions in the galactic plane where the scattering is an order of magnitude higher than the average, as well as directions where the scattering is much lower. The latter provide an opportunity to investigate OH masers with the full angular resolution offered by very long baseline interferometry instruments, like the VLBA, and measure their true angular size, shape and brightness temperature. We have observed approximately 100 OH maser sources, distributed all over the northern hemisphere, with the VLBA in order to study the scattering properties of the interstellar medium.

• Journal of Power System Engineering
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• v.3 no.1
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• pp.55-59
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• 1999

Generally, T.G(Tacho-generator, Tachometer) sensor is used widely for sensing the angular velocity in rotary machine. By limitation of T.G sensor's structure, the sensed angular velocity include a periodic noise, and the noise is called "ripple" as an electrical term. To reduce the effecting of the ripple, many kinds of filters are designed and installed, but there is necessary a trade off between response time and adapted frequency band. In this paper, we propose a generalized observer to estimate an angular velocity from the output signal of T.G sensor. The generalized observer is proposed firstly for continue systems, and it is applied to DC servo motor with T.G sensor. For simulation, we measure T.G signals at 60, 400, 570 rpm respectively, and analysis those to obtain the resonance frequency of ripple by FFT method. To verify the effectiveness of the proposed algorithm, we compare the results with those of a RC low frequency band filter.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.223-232
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• 2014

An inductive sensor system is proposed to detect the gear location and angular position of a geared shaft for automatic feeding of the shaft into the proper cutting position of the other end. The system consists of two set of coils, bridge circuit, signal condition circuit, and microprocessor. The coil sensors of the system measure changes of inductance along with the surface position of a geared shaft. The inductance changes are transformed to voltages by the bridge circuit, which are then conditioned and processed for the recognition of the gear. In order to incorporate with the experimental results with the sensor system, a finite element method (FEM) simulation for the magnetic field between the sensor and the shaft was carried out. The predicted results and the experiments revealed that the sensor system was appropriate for sensing the position of gear and the angular position of gear tooth of a geared shaft.

• The Journal of the Korea Contents Association
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• v.8 no.2
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• pp.27-32
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• 2008

In this paper, we propose an orientation tracking method and a digestion path model based on angular displacement. The proposed method expresses a capsule's orientation as 3-dimension vectors and its rotation angle. Errors in roll, pitch, and yaw representing capsule's orientation information is down to $1.6^{\circ}$. Using the proposed method we can measure a roll which is not Possible to be measured using the magnetic field method. We reduce algorithm complexity lower than a previous methods based on Euler angle.

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.317-327
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• 2014

As a single subject study, it was purposed to investigate kinematic differences between Yang Hak Seon vault (i.e., handspring forward and salto forward straight with triple twist, Yang-1 vault hereafter) and Tsukahara $1260^{\circ}$ twist with salto forward straight (Yang-2 vault hereafter) in gymnastics. Yang Hak-Seon (23 years, 160 cm, and 52 kg) voluntarily participated in this study. Motion capture system, consisting of fourteen cameras, were used to measure Yang-2 vault with the sampling rate of 200 Hz. Twenty six reflective markers were placed on major anatomical points of 15 body segments. Successful two trials of Yang-2 vault were collected and analyzed for the comparison. Compared Yang-1 results were based on the previous study of Park and Song (2012). Results indicated superior linear kinematics of Yang-1 vault to those of Yang-2 vault before the touchdown of vault table. However, Yang-2 vault revealed superior angular kinematics to Yang 1 vault showing more trunk twist angle (a triple and a half twist) and its faster angular velocity during the airborne. The Yang 2 vault could has advantage of increasing angular motion than Yang 1 vault as a result of a half turn off the springboard onto the vault table and a sequential touchdown of the hands.

• Journal of Biosystems Engineering
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• v.5 no.2
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• pp.40-57
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• 1980

The aim of this study was to promote extensive use of strain gage for accurate measurement in the area of farm machinery research. The results are summarized as follows. 1. Although many strain gate transducers commercially available such as load-cells , accelerometers and pressure transducers have been used in the area of farm machinery research, many types of transducers had to be developed due to the inadaptability or high cost commercial transducers, in many instances. 2. A strain -gaged cantilever beam could be used as a good educational material to demonstrate the methods of Wheatstone bridge arrangement, calibration and theoreticval computation. A ring type load-cell and shaft torque transducer also could be used for the same purpose. 3. The torque and angular speed transducers for an auto-feed thresher and the displacement and pressure transducers for a rice whitener were made and gave satisfactory results. 4. Based on the above results, it is possible to develop simple and low-cost transducers to measure displacement, angular speed , torque and pressure of farm machine elements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.871-877
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• 2018

In this paper, we propose a triple nested PID control scheme for stable hovering of a quadrotor and propose a complementary filter based sensor fusion technique to improve the performance of attitude, altitude and velocity measurement. The triple nested controller has a structure in which a double nested attitude controller that has the angular velocity PD controller in inner loop and the angular PI controller in outer loop, is nested in a velocity control loop to enable stable hovering even in the case of disturbance. We also propose a sensor fusion technique by applying a complementary filter in order to reduce the noise and drift error included in the acceleration and gyro sensor and to measure the velocity by fusing image, gyro, and acceleration sensor. In order to verity the performance, we applied the proposed control and measurement scheme to hovering control of quadrotor.