• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1170-1175
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• 2003

Recently, the disturbance caused by an optical disk vibration and the external vibration/shock are more serious problem in an optical disk drives (ODD) as an ODD become small size and rotation speed increases. The conventional controller cannot cope with the mentioned problems properly when the disturbance and vibration are larger than some range. Therefore, we propose a new control scheme using a disturbance observer (DOB) and it can control the aforementioned problems. The designed the controller is applied to a commercial ODD in focusing direction, then its validity is proved by experimental method. By rising the disturbance observer theory, the focusing performance is conspicuously improved in the presence of sinusoidal vibrations or a shock disturbance. This algorithm also applies to a tracking structure also, because focusing structure is very similar to it.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2216-2218
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• 2000

This paper deals with finite element eigenvalue problem using electric field intensity to extract the even and odd impedance for a coupled-line waveguide structure. Calculations for the even-and-odd impedance of a coupled line waveguide structure are achieved based on the relative impedance concept for a waveguide with electric and magnetic wall containes.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.6
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• pp.372-375
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• 2005

The tracking performance of optical disk drive(ODD) system can be improved using disturbance observer(DOB). But, DOB was not easily applied in the ODD system because the additional microprocessor was needed. In this paper, we propose an error-based modified disturbance observer(EM-DOB) for ODD system. Due to the simplified structure of EM-DOB, the system is easily implemented to the digital control algorithm or the analog circuit. In these algorithms, disturbances rejection performance of system can be tuned as Q filter parameters are selected. Based on analysis of sensitivity function, three guidelines of Q filter design are suggested. Experimental results of DOB and EM-DOB are evaluated under the forced disturbances.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.156-162
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• 2006

In this paper, we have investigated the disc warping in high-speed slim-type optical disc drive. The track density as well as high rotational speed of the information storage devices must be increased to enhance their recording capacity and data transfer rate. Generally, ODD used in the Lap-top computer has small inner space. So, the flow instability of the inner space is increased rapidly with its rotational speed. In extreme case, the flow instability may cause the malfunction of the read/write pick-up of drives. The experiments and numerical analysis were carried out for several cases and the result shows the influence of airflow to the disc warping.

• Transactions of the Society of Information Storage Systems
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• v.6 no.2
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• pp.57-62
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• 2010

This paper measured and analyzed the source of total power loss of an ODD of a notebook computer. It shows that the biggest power loss is the windage loss due to the friction between rotating disk and surrounding air. It measured the power loss by the tilting motion of a rotating disc which is originated from the unbalanced mass of the rotating disc or the squareness between case-rotor and shaft. The power loss of rotating disc due to tilting motion was also calculated by using FLUENT, and it was correlated with the measured one. This paper shows that the one of the effective methods to reduce the power loss of an ODD is to reduce the tilting motion of a rotating disc.

• Kyungpook Mathematical Journal
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• v.61 no.1
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• pp.49-59
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• 2021

Recently, Andrews introduced partition functions ����(n) and ${\bar{\mathcal{EO}}}$(n) where the function ����(n) denotes the number of partitions of n in which every even part is less than each odd part and the function ${\bar{\mathcal{EO}}}$(n) denotes the number of partitions enumerated by ����(n) in which only the largest even part appears an odd number of times. In this paper we obtain some congruences modulo 2, 4, 10 and 20 for the partition function ${\bar{\mathcal{EO}}}$(n). We give a simple proof of the first Ramanujan-type congruences ${\bar{\mathcal{EO}}}$ (10n + 8) ≡ 0 (mod 5) given by Andrews.

• IEMEK Journal of Embedded Systems and Applications
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• v.19 no.2
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• pp.115-121
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• 2024

Each ADS must have a validation and evaluation scenario for ODD. This requires a large number of scenarios, so a scenario library must be developed. In order to effectively utilize the scenario library, a system that supports testing in the ODD of the user's choice is required. In other words, in order to develop a scenario library, it is necessary to build a database on actual driving road conditions (geometry, etc.). Accordingly, in this study, we establish a domestic driving environment database based on HD-Map for driving safety testing, design a system that can search test target sections in connection with the ODD of the scenario, and present the implementation results. In the future, it is expected that the domestic driving environment database will be able to create scenarios through linking with the scenario library and directly utilize them for scenario-based evaluation of various demand sources.

• KSBB Journal
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• v.8 no.1
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• pp.49-54
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• 1993

The contents of odd number fatty acid in walnut, peach seed and apricot seed were analyzed by HPLC. The results were as follows; the contents of crude oil in walnut, peach seed and apricot seed were 61.7%, 48.21%, and 52.34%, respectively. The contents of neutral lipid in walnut peach seed, and apricot seed were contained 62.32%, 91.50%, and 88.00%, respectively. The contents of glycolipid in walnut peach seed and apricot seed were contained 34.14%, 3.25%, and 4.78%, respectively. The contents of phospholipid in walnut peach seed and apricot seed were contained 3.54%, 5.25%, and 7.27%, respectively. The contents of odd number fatty acid and even number fatty acid in neutralipid were walnut 37.07% and 36.72%, peach seed 5.4% and 94.60%, and apricot seed 6.85% and 93.92%, respectively. The contents of odd number fatty acid and even number fatty acid in glycolipid were walnut 5.37% and 46.21%, peach seed 6.97% and 89.42%, and apricot seed 10.50% and 89.42%, respectively. The contents of odd number fatty acid and even number fatty acid in phospholipld were walnut 3.57% and 96.43%, peach speed 6.51% and 93.49%, and apricot seed 15.00% and 84.20%, respectively. The contents of odd number fatty and even number fatty acid in total fatty acid were walnut 14.47% and 85.53%, peach seed 1.17% and 98.83%, and apricot seed 4.3% and 95.97%, respectively.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.259-267
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• 2005

In 2000 a general conjecture was proposed: a special polygon cannot be cut into an odd number of triangles of equal areas. It has been proved that the conjecture holds for polygons with at most six sides. In this paper we prove the existence of special n-polygon for any integer n > 6 and discuss the conjecture for special polygons with seven sides.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.2
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• pp.287-295
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• 2014

In this paper, we prove that the image of the representation of the automorphism group of a supersingular K3 surface of Artin-invariant 1 over odd characteristic p on the global two forms is a finite cyclic group of order p + 1. Using this result, we deduce, for such a K3 surface, there exists an automorphism which cannot be lifted over a field of characteristic 0.