• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.739-741
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• 2004

최장 공통 부분 스트링이란 주어진 두 개 이상의 스트링에서 가장 길게 일치하는 공통 부분 스트링을 계산하는 문제이다 최장 공통 부분 스트링은 스트링 프로세싱이나 생물정보학 분야에서 널리 사용되고 있는 중요한 문제이지만, 현재까지 연구된 동적 프로그래밍이나 써픽스 트리를 사용한 방법은 저장 공간을 많이 차지하므로 효율적이지 못하다 따라서 적은 저장 공간을 차지하면서도 최장 공통 부분 스트링을 빨리 구할 수 있는 알고리즘이 필요하며, 본 논문에서는 이를 위해 써픽스 배열을 도입하였다. 본 논문에서 제시한 알고리즘은 선형 시간, 공간 복잡도를 가지며, 써픽스 트리의 최하 공통 조상(LCA, Lowest Common Ancestor) 연산이나 써픽스 배열에서 사용하는 그와 비슷한 구간 최소 값 질의(RMQ, Range Minima Query)를 전혀 사용하지 않으므로 매우 효율적이다.

• The Journal of Korea Robotics Society
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• v.16 no.4
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• pp.313-318
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• 2021

This paper proposes a new method to generate inverse reachability maps that are more efficient for mobile manipulators than the previous algorithms. The base positioning is important to perform the given tasks. Using the inverse reachability method, we can know where to place the robot's base for given tasks. For example, the robot successfully performed the task with relocation, even when the target is initially in a low manipulability area or outside the workspace. However, there are some inefficiencies in the online process of the classical inverse reachability method. We describe what inefficiencies appear in the online phase and how to change the offline process to make the online efficient. Moreover, we demonstrate that the proposed approach achieves better performance than usual inverse reachability approaches for mobile manipulation. Finally, we discuss the limitations and advantages of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.8
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• pp.36-46
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• 2010

In multi-GHz RF ICs and high-speed digital interfaces, ESD protection devices introduce considerable parasitic capacitance and resistance to inputs and outputs, thereby degrading the RF performance, such as input/output matching, gain, and noise figure. In this paper, the impact of ESD protection devices on the performance of RF ICs is investigated and design methodologies to minimize this impact are discussed. With RF and ESD test results, the 'RF/ESD co-design' method is discussed and compared to the conventional RF ESD protection method which focuses on minimizing the device size.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.971-980
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• 1994

The need increased capacity in the cellular system has resulted in the adoption of digital technology with CDMA as the channel access method. It has been recognized that the distinction of the base station is important for its performance in CDMA, since the same spreading sequences are used by the all base stations. Time offset of the pseudo-random noise binary code are used to distinguish signals received at a mobile station from different base station. But the start of the zero offset PN sequence is chosen arbitrary without the background of the systematic and mathematical elaboration. This paper proposes a mothed that define the start of the zero offset PN sequence mathematically. This paper also discusses a method that can easily calculate the time offset of the received spreading sequence with respect to the zero offset PN sequence.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.620-623
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• 2010

구조요소의 설계에서 유한요소해석은 매우 효과적인 방법이며 정확한 해석 기술을 요구한다. 그러나 제조 공정이나 환경에 따라 달라지는 재료 물성이나 불확실성을 내포하는 피로 물성을 확정적인 값으로 이용하는 등 입력 변수의 부정확한 정보로 인해 유한요소해석 결과를 신뢰하지 못하는 경우가 자주 발생한다. 실제 시험을 통해 설계의 결과를 예측하는 것은 경제적인 측면과 시간소요 면에서 한계가 따르기에 신뢰할 수 있는 유한요소해석 방법이 요구된다. 본 연구에서는 고주기의 피로 해석을 위해 유한요소해석을 이용하여 스프링의 응력-수명(S-N) 파라미터를 역 추정하고 수명을 예측해 보았다. 이를 위해 실제 산업현장에서 쓰이는 자동차 서스펜션 코일 스프링을 예제로 사용하였다. 시험 모델에 대해 불확실성을 고려한 베이지안 접근법을 이용하여 입력변수의 파라미터를 역 추정하였으며, 마코프체인몬테카를로(Markov Chain Monte Carlo) 기법을 이용하여 얻어진 피로 물성 파라미터의 샘플 데이터를 이용해서 유한요소해석을 실시하고 신뢰수준 내에서 새로운 구조요소의 피로수명을 예측하였다.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.597-608
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• 2003

A transcritical flow occurs when the width and slope of a channel are varying abruptly. In this study, the transcritical flow in a two-dimensional open channel is analyzed by using the shallow-water equations. A weighted average flux scheme that has flux limiter with a total variation diminishing condition is introduced for a second-order accuracy in time and space, and non- spurious oscillations at discontinuous points. A HLLC method with three wane speeds is employed to calculate the Riemann problem. To overcome difficulties resulting from variation of channel sections in a two-dimensional analysis of transcritical flow, the numerical model is developed based on a generalized grid system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.2
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• pp.117-132
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• 2014

This paper had a purpose on analyzing result data from pan-sharpening, which have applied on the KOMPSAT-2 and -3 image. Particularly, the study focused on comparing each relative spectral response functions, which considers to cause color distortions of fused image. Two images from same time and location have been collected by KOMPSAT-2 and -3 to apply in the experiment. State-of-the-art algorithms of GIHS, GS1, GSA and GSA-CA were employed for analyzing the results in quantitatively and qualitatively. Following analysis of previous studies, GSA and GSA-CA methods resulted excellent quality in both of KOMPSAT-2/3 results, since they minimize spectral discordances between intensity and PAN image by the linear regression algorithm. It is notable that performances from KOMPSAT-2 and- 3 are not equal under same circumstances because of different spectral characteristics. In fact, KOMPSAT-2 is known as over-injection of low spatial resolution components of blue and green band, are greater than that of the PAN band. KOMPSAT-3, however, has been advanced in most of misperformances and weaknesses comparing from the KOMPSAT-2.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.6
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• pp.41-50
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• 2003

For copyright protection of digital contents, we employ watermarking techniques to embed watermark signals into digital host data. In this paper we propose an adaptive watermarking algorithm for three-dimensional (3-D) mesh models. Watermark signals are inserted into vertex coordinates adaptively according to changes of their position values. While we embed strong watermarks in the areas of large variations, watermarks are weakly inserted in other areas. After we generate triangle strips by traversing the 3-D model and convert the Cartesian coordinates to the spherical coordinate system, we calculate variations of vertex positions along the traversed strips. Then, we insert watermark signals into the vertex coordinates adaptively according to the calculated variations. We demonstrate that imperceptibility of the inserted watermark is significantly improved and show the bit error rate (BER) for robustness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.151-157
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• 2011

This study analyzed the posture balance of time variation for exercising body a period of time. Posture balance measured output values for the posture balance system of body moving in the multi-parameter. Posture moving variation had three methods such as open and closed eye, head moving and upper body moving. There were checked a parameter that measured vision, vestibular, somatosensory, CNS. This system was evaluated a data through the stability. This system has catched a signal for physical condition of body data such as a data acquisition system, data signal processing and feedback system. The output signal was generated Fourier analysis that using frequency of 0.1Hz, 0.1-0.5Hz, 0.5-1Hz and 1Hz over. The posture balance system will be used to support assessment for body moving the posture balance of time variation. It was expected to monitor a physical parameter for health verification system.

• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1283-1297
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• 2023

Mid-wave infrared (MWIR) imagery, due to its ability to capture the temperature of land cover and objects, serves as a crucial data source in various fields including environmental monitoring and defense. The KOMPSAT-3A satellite acquires MWIR imagery with high spatial resolution compared to other satellites. However, the limited spatial resolution of MWIR imagery, in comparison to electro-optical (EO) imagery, constrains the optimal utilization of the KOMPSAT-3A data. This study aims to create a highly visible MWIR fusion image by leveraging the edge information from the KOMPSAT-3A panchromatic (PAN) image. Preprocessing is implemented to mitigate the relative geometric errors between the PAN and MWIR images. Subsequently, we employ a pre-trained pixel difference network (PiDiNet), a deep learning-based edge information extraction technique, to extract the boundaries of objects from the preprocessed PAN images. The MWIR fusion imagery is then generated by emphasizing the brightness value corresponding to the edge information of the PAN image. To evaluate the proposed method, the MWIR fusion images were generated in three different sites. As a result, the boundaries of terrain and objects in the MWIR fusion images were emphasized to provide detailed thermal information of the interest area. Especially, the MWIR fusion image provided the thermal information of objects such as airplanes and ships which are hard to detect in the original MWIR images. This study demonstrated that the proposed method could generate a single image that combines visible details from an EO image and thermal information from an MWIR image, which contributes to increasing the usage of MWIR imagery.