• Proceedings of the Optical Society of Korea Conference
• /
• 2001.02a
• /
• pp.64-65
• /
• 2001

HDDS(Holographic Digital Data Storage) 시스템에서 저장밀도가 증가함에 따라서 기록/재생된 데이터는 중첩된 페이지 사이의 간섭과 인접 픽셀간의 간섭에서 기인하는 ISI (Intersymbol Interference) 및 Speckle 잡음을 포함하는 Random Noise와 광학 수차, 광학정렬 오차 및 Laser 광원의 비균일 광강도 분포 등에서 기인하는 Non- random Noise 등 다양한 시스템 잡음에 의해서 BER 이 급격히 저하되는 문제가 발생된다. 113 이러한 문제점을 해소하고 시스템의 기록/재생 데이터 신뢰도를 확보하기 위해서는 적절한 광신호처리 기법과 coding 기법이 도입되어야만 한다. (중략)

• Proceedings of the Optical Society of Korea Conference
• /
• 2001.02a
• /
• pp.92-93
• /
• 2001

주파수 안정화 레이저 광원은 10-6 이상의 상대 불확도가 필요한 간섭계에서 널리 쓰이고 있으며 특히 변위 측정 시스템에서는 반드시 쓰이고 있다. 상용화된 많은 변위 측정 시스템은 신호 대 잡음비가 우수하고 광학계의 정렬이 더 쉬운 헤테로다인 방식을 채택하고 있으며 이를 위해서 서로 수직 선형 편광인 다른 주파수의 광을 내보내는 광원이 필요하다. 현재 헤테로다인 변위 측정 시스템에 쓰이고 있는 광원은 이중 주파수 광원을 만드는 방식에 따라 지만 효과(Zeeman effect)를 이용한 지만 레이저(HP사)와 음향-광 변조기(Acousto-optic modulator)를 이용한 이중 주파수 레이저(Zy해사)가 있다. (중략)

• Proceedings of the KIEE Conference
• /
• 2000.07d
• /
• pp.2886-2888
• /
• 2000

본 논문은 다수의 이동로봇들의 협조운동을 위해서 퍼지알고리즘을 적용하였다. 그리고. 보다 정확한 정보획득을 위해서 슈퍼바이저 시스템의 적용을 제안한다. 제안된 알고리즘에 대한 효과는 등간격원 모양으로 로봇들이 정렬할 때까지의 시간으로 나타내었으며, 슈퍼바이저 시스템을 적용한 것과 그렇지 않은것에 대한 비교를 컴퓨터 모의실험으로 그 결과를 보였다.

• Journal of the Korea Computer Graphics Society
• /
• v.23 no.5
• /
• pp.9-17
• /
• 2017

Filming using multiple cameras is required for the production of the multi-screen content. It can fill the viewer's field of view (FOV) entirely to provide an increased sense of immersion. In such a filming scenario, it is very important to monitor how images captured by multiple cameras are displayed as a single content or how the content will be displayed in an actual theatre. Most recent studies on creating the content of special format have been focused on their own purposes, such as stereoscopic and panoramic images. There is no research on content creation optimized for theatres that use three screens that are spreading recently. In this paper, we propose a novel content production system with a rig that can control three cameras and monitoring software specialized for multi-screen content. The proposed rig can precisely control the angles between the cameras and capture wide angle of view with three cameras. It works with monitoring software via remote communication. The monitoring software automatically aligned the content in real time, and the alignment of the content is updated according to the angle of camera rig. Futher, the producion efficiency is greatly improved by making the alignment information available for post-production.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.2
• /
• pp.69-80
• /
• 1999

Recently, social requirements of personal identification techniques are rapidly expanding in a number of new application ares. Especially fingerprint recognition is the most important technology. Fingerprint recognition technologies are well established, proven, cost and legally accepted. Therefore, it has more spot lighted among the any other biometrics technologies. In this paper we propose a new on-line fingerprint recognition algorithm for non-inked type live scanner to fit their increasing of security level under the computing environment. Fingerprint recognition system consists of two distinct structural blocks: feature extraction and feature matching. The main topic in this paper focuses on the feature matching using the fingerprint minutiae (ridge ending and bifurcation). Minutiae matching is composed in the alignment stage and matching stage. Success of optimizing the alignment stage is the key of real-time (on-line) fingerprint recognition. Proposed alignment algorithm using clique shows the strength in the search space optimization and partially incomplete image. We make our own database to get the generality. Using the traditional statistical discriminant analysis, 0.05% false acceptance rate (FAR) at 8.83% false rejection rate (FRR) in 1.55 second average matching speed on a Pentium system have been achieved. This makes it possible to construct high performance fingerprint recognition system.

• Journal of KIISE:Computer Systems and Theory
• /
• v.31 no.10
• /
• pp.593-602
• /
• 2004

A new surface reconstruction scheme for approximating the surface from a set of unorganized 3D points is proposed. Our method, called shrink-wrapped boundary face (SWBF) algorithm, produces the final surface by iteratively shrinking the initial mesh generated from the definition of the boundary faces. Proposed method surmounts the genus-0 spherical topology restriction of previous shrink-wrapping based mesh generation technique, and can be applicable to any kind of surface topology. Furthermore, SWBF is much faster than the previous one since it requires only local nearest-point-search in the shrinking process. According to experiments, it is proved to be very robust and efficient for mesh generation from unorganized points cloud.

• Korean Journal of Cognitive Science
• /
• v.24 no.4
• /
• pp.301-321
• /
• 2013

For the task of sentence ordering, this paper attempts to utilize the Entity-Grid model, a type of entity-based modeling approach, as well as Latent Semantic analysis, which is based on vector space modeling, The task is well known as one of the fundamental tools used to measure text coherence and to enhance text generation processes. For the implementation of the Entity-Grid model, we attempt to use the syntactic roles of the nouns in the Korean text for the ordering task, and measure its impact on the result, since its contribution has been discussed in previous research. Contrary to the case of German, it shows a positive result. In order to obtain the information on the syntactic roles, we use a strategy of using Korean case-markers for the nouns. As a result, it is revealed that the cues can be helpful to measure text coherence. In addition, we compare the results with the ones of the LSA-based model, discussing the advantages and disadvantages of the models, and options for future studies.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.11
• /
• pp.1637-1642
• /
• 2010

In this paper, we present the fabrication of a high-quality diffractive-lens mold having submicron patterns, which is suitable for an ultra-slim optical system. In order to fabricate high-quality diffractive lens with a variety of submicron patterns, the multi-alignment method was used; high-resolution electron-beam lithography and FAB plasma etching were carried out to obtain the patterns. The most important key technology in the multi-alignment method is to reduce alignment error, lithography error, and etching error. In this paper, these major fabrication errors were minimized, and a high-quality diffractive lens with a diameter of $267\;{\mu}m$ (NA = 0.25), minimum pattern width of 226 nm, and thickness of 819 nm was successfully fabricated.

• Journal of Advanced Navigation Technology
• /
• v.26 no.4
• /
• pp.235-243
• /
• 2022

In this paper, in the case of an inertial navigation system, the posture estimation error in the initial alignment due to vertical deflection is analyzed. Posture estimation error due to DOV was theoretically analyzed based on the speed and posture error of INS. Simulations were performed to verify the theoretical grinding, and the results were in good agreement. For example, in the case of η=20", an alignment error of ϕ_N=0.00287°, ϕ_U=0.00196° occurred, and in the case of 𝜉=20", an error of ϕ_E= -0.00286° occurred. Through this, it was confirmed that the vertical posture error caused by the DOV occurred as a coupling characteristic of the INS posture error. It has been shown that an additional posture error may occur due to the DOV, which was not considered in the existing INS alignment, which means that correction for the DOV must be considered when applying high-precision INS.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.1
• /
• pp.17-27
• /
• 2005

In this paper, we introduce a Parallel Interference Canceller (PIC) based sorting method to improve performance in the MC-DS/CDMA environment. A conventional PIC estimates and subtracts out all of the MAI (Multiple Access Interference) for each user in parallel. The parallel process ensures the low delay for the detection of all users. Also this scheme requires more stages for having better performance. Since the performance of PIC is strongly related to the correct MAI estimation, we introduce the IC (Interference Cancellation) scheme to estimate the accurate weaker signal group than the desired signal using conventional PIC. The principle of the proposed receiver sorts in descending order by the strength of signal and subtracts the MAI of the strong interferers from the desired signal for the accurate estimate of the weaker signals. Following this, the proposed scheme cancels out the improved weaker interference from the desired signal, using the output of the pre-step. In this result, the proposed system obtains better BER performance than the conventional PIC because the accuracy of the strong signal is improved. However, a disadvantage exists in that the processing time has slightly longer delay than the PIC owing to the power sorting and the MAI estimation process. The system performance evaluates and compares other non-liner It according to the number of sub-carriers in the limited-bandwidth.