• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1742-1747
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• 2015

An improved transfer alignment method for a strap-down inertial navigation system (SDINS) is presented here. The alignment accuracy in conventional method is vulnerable to the data latency of a Master INS (MINS) in high maneuverable platforms. We propose a time delay compensation equation considering higher-order terms in the attitude measurement equation of the Kalman filter. The equation incorporates additional information including angular rate, angular acceleration and linear acceleration from the MINS. Simulation results show that the transfer alignment accuracy is significantly improved in the high dynamic environment by incorporating the latency compensation technique.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.710-726
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• 2018

This paper presents an extended particle filter to increase the accuracy and decrease the computation load of vehicle tracking. Particle filter has been the subject of extensive interest in video-based tracking which is capable of solving nonlinear and non-Gaussian problems. However, there still exist problems such as preventing unnecessary particle consumption, reducing the computational burden, and increasing the accuracy. We aim to increase the accuracy without an increase in computation load. In proposed method, we calculate the direction angle of the target vehicle. The angular difference between the direction of the target vehicle and each particle of the particle filter is observed. Particles are filtered and weighted, based on their angular difference. Particles with angular difference greater than a threshold is eliminated and the remaining are stored with greater weights in order to increase their probability for state estimation. Threshold value is very critical for performance. Thus, instead of having a constant threshold value, proposed algorithm updates it online. The first advantage of our algorithm is that it prevents the system from failures caused by insufficient amount of particles. Second advantage is to reduce the risk of using unnecessary number of particles in tracking which causes computation load. Proposed algorithm is compared against camshift, direction-based particle filter and condensation algorithms. Results show that the proposed algorithm outperforms the other methods in terms of accuracy, tracking duration and particle consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8A
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• pp.752-759
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• 2006

In this paper, the performances of representative high resolution direction finding algorithms are evaluated and compared in wideband mobile environments. The angular spread phenomenon in mobile environments is first investigated and then a vector channel model for wideband OFDMA signals is derived. A direction finding system architecture for OFDMA smart antenna systems is proposed and finally the performances of high resolution direction finding algorithms are evaluated in wideband mobile environments by taking the WiBro system as a target system.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.251-253
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• 2002

We have fabricated a novel Vertical Trench Hall-Effect Device sensitive to the magnetic field parallel to the sensor chip surface for non-contact angular position sensing applications. The Vertical Trench Hall-Effect Device is built on SOI wafer which is produced by silicon direct bonding technology using bulk micromachining, where buried $SiO_2$ layer and surround trench define active device volume. Sensitivity up to 150 V/AT is measured.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.11 no.3
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• pp.63-69
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• 2001

Smartcard is highlighted as infrastructure that has an excellent security for executing functions such as user authentication, access control, information storage and control, and its market is expanding rapidly. But possibilities of forgery and alteration by hacking are increasing as well. This paper proposes a method to prevent card forgery and alteration using angular multiplexing and private key multiplexing method on optical encryption, and proposed a Public Key Infrastructure(PKI)-based authentication system combined with One-Time Password (OTP) for verification of forgery and alteration .

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.2
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• pp.27-32
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• 2004

Absolute optical angle sensor is described that is an essentially digital opto-electronic device. Its purpose is to resolve the relative and absolute angle position of coded disk using Pseudorandom-code and Geometry-code. In this technique, the angular position of disk is determined in coarse sense first by Pseudorandom-code. A further fine angular position data based on Pixel count is obtained by Geometry-code which result 0.006$^{\circ}$ resolution of the system provided that 7 ${\mu}{\textrm}{m}$ line image sensor are used. The proposed technique is novel in a number of aspects, such that it has the non-contact reflective nature, high resolution of the system, relatively simple code pattern, and inherent digital nature of the sensor. And what is more the system can be easily modified to torque sensor by applying two coded disks in a manner that observe the difference in absolute angular displacement. The digital opto-electronic nature of the proposed sensor, along with its reporting of both torque and angle, makes the system ideal for use in intelligent vehicle systems. In this communication, we propose a technique that utilizes Pseudorandom-code and Geometry-code to determine accurate angular position of coded disk. We present the experimental results to demonstrate the validity of the idea.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.26-36
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• 2012

Since shape of an object in an image carries important information in contents based image retrieval (CBIR), many shape description methods have been proposed to retrieve images using shape information. Among the existing shape based image retrieval methods, the method which employs invariant Zernike moment desciptor (IZMD) showed better performance compared to other methods which employ traditional Zernike moments descriptor in CBIR. In this paper, we propose a new image retrieval method which applies invariant angular radial transform descriptor (IARTD) to obtain higher performance than the method which employs IZMD in CBIR. IARTD is a rotationally invariant feature which consists of magnitudes and alligned phases of angular radial transform coefficients. To produce rotationally invariant phase coefficients, a phase correction scheme is performed while extracting the IARTD. The distance between two IARTDs is defined by combining the differences of the magnitudes and the aligned phases. Through the experiment using MPEG-7 shape dataset, the average bull's eye performance (BEP) of the proposed method is 0.5806 while the average BEPs of the exsiting methods which employ IZMD and traditional ART are 0.4234 and 0.3574, respectively.

• Journal of Multimedia Information System
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• v.7 no.2
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• pp.189-196
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• 2020

We have developed a device for recording biological data by inserting three electrodes and a needle with an angular velocity sensor into the moth for the purpose of measuring the electromyogram of the flapping and the corresponding lift force. With this measurement, it is possible to evaluate the moth-physiological function of moths, and the amount of pesticides that insects are exposed to (currently LD50-based standards), especially the amount of chronic low-concentration exposure, can be reduced the dose. We measured and recorded 2-channel electromyography (EMG) and angular velocity corresponding to pitch angle (pitch-like angle) associated with wing flapping for 100 sweet potato hawkmoths (50 females and 50 males) with the animals suspended and constrained in air. Overall, the angular velocity and amplitude of EMG signals demonstrated high correlation, with a correlation coefficient of R = 0.792. In contrast, the results of analysis performed on the peak-to-peak (PP) EMG intervals, which correspond to the RR intervals of ECG signals, indicated a correlation between ΔF fluctuation and angular velocity of R = 0.379. Thus, the accuracy of the regression curve was relatively poor. Using a DC amplification circuit without capacitive coupling as the EMG amplification circuit, we confirmed that the baseline changes at the gear change point of wing flapping. The following formula gives the lift provided by the wing: angular velocity × thoracic weight - air resistance - (eddy resistance due to turbulence). In future studies, we plan to attach a micro radio transmitter to the moths to gather data on potential energy, kinetic energy, and displacement during free flight for analysis. Such physiological functional evaluations of moths may alleviate damage to insect health due to repeated exposure to multiple agrochemicals and may lead to significant changes in the toxicity standards, which are currently based on LD50 values.

• Korean Journal of Remote Sensing
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• v.32 no.1
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• pp.61-65
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• 2016

Importance of remote sensing for surface is increased than past. So many countries try to many ways to retrieve surface reflectance. In this study, we study a Bidirectional Reflectance Distribution Function (BRDF) to retrieve surface reflectance. We apply BRDF using observed surface reflectance of SPOT/VEGETATION (VGT-S1) and angular data to get Bidirectional Reflectance Distribution (BRD) coefficients for calculating scattering. And then we apply BRDF in the opposite direction with BRD coefficients and angular data to retrieve Background Surface Reflectance (BSR). The range of BSR is not over $0.4{\mu}m$ (blue), $0.45{\mu}m$ (red), $0.55{\mu}m$ (NIR). And for validation we compare BSR with VGT-S1, there are bias is from 0.0116 to 0.0158 and RMSE is from 0.0459 to 0.0545. As a result, we confirm that BSR is similar to VGT-S1.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.9
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• pp.31-37
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• 2000

An angular selectivity through the focused readout beam is geometrically analyzed and experimental results are presented. Based on the analysis of geometrical results, we derive a new relation that the angular selectivity depends on incident conditions of the readout beam and independent on the writing conditions. In order to demonstrate our theory, we investigate angular selectivity as functions of following factors: writing beam incident angle, readout beam width and lens focal length. From the experimental results, it is shown that the angular selectivities are 2.632$^{\circ}$, 2.618$^{\circ}$, 2.604$^{\circ}$ when the external half-crossing angles of writing beam are 8$^{\circ}$, 10$^{\circ}$, 14$^{\circ}$, respectively. Applying the same incident angle of the recording beam, angular selectivity is changed by the control of readout beam width and then their properties are 2.632$^{\circ}$, 0.588$^{\circ}$. From these results, we have known that the angular selectivity is very critical to incident conditions of readout beam.