• Journal of Astronomy and Space Sciences
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• 제38권3호
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• pp.185-192
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• 2021

This technical paper deals the practical transformation algorithms between several lunar reference frames which will be used for Korea pathfinder lunar orbiter (KPLO) flight operation. Despite of various lunar reference frame definitions already exist, use of a common transformation algorithm while establishing lunar reference frame is very important for all members related to KPLO mission. This is because use of slight different parameters during frame transformation may result significant misleading while reprocessing data based on KPLO flight dynamics. Therefore, details of practical transformation algorithms for the KPLO mission specific lunar reference frames is presented with step by step implementation procedures. Examples of transformation results are also presented to support KPLO flight dynamics data user community which is expected to give practical guidelines while post processing the data as their needs. With this technical paper, common understandings of reference frames that will be used throughout not only the KPLO flight operation but also science data reprocessing can be established. It is expected to eliminate, or at least minimize, unnecessary confusion among all of the KPLO mission members including: Korea Aerospace Research Institute (KARI), National Aeronautics and Space Administration (NASA) as well as other organizations participating in KPLO payload development and operation, or further lunar science community world-wide who are interested in KPLO science data post processing.

• 대한기계학회논문집
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• 제15권2호
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• pp.497-506
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• 1991

In this paper, a new construction for training simulator of R/C helicopter based on two types of servo controller is proposed. Two modified algorithms (algorithm I and II) for servo controller design are presented. Algorithm I is developed by adopting Davison's method in the case that the expressions for the homogeneous differential equations of reference input and disturbance are different types, and algorithm II is done by considering error weighting function for the servo controller of algorithm I . The linear fractional transformation method is incorporated in both design methods in order to assign the closed loop poles of the servo system in a specified region. The helicopter simulator is composed by the gimbals with two freedom of rolling and pitching. The reliability and validity for the design methods of the proposed servo controller are investigated through the practical experiment for the simulator by using 16bits micro-computer with A/D and D/A converters. It can be observered from the experimental results that the proposed servo controller is applicable to practical plants since the simulator is robust for the arbitrary disturbance and it follows to the given reference input without significant steady state error.

• 대한전기학회논문지:전력기술부문A
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• 제48권9호
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• pp.1055-1063
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• 1999

This paper present a conceptual possibilistic approach using fuzzy set theory to manage the uncertainties in the given reliability input date of the practical power system. In this paper, an algorithm is introduced to calculate the possibilstic reliability indices according to the degree of uncertainty in the given data. The probability distribution function can be transformed into an appropriate possibilstic representation using the probability-Possibility Consistency principle(PPCP) algorithm. In this the algorithm, the transformation is performation by making a compromise between the transformation consistency and the human updating experience. Fuzzy classifcation theory is applied to reduced the number of load data. The fuzzy classification method determines the closeness of load data points by assigning them to various clusters and then determening the distance between the clusters. The IEEE-RTS with 32-generating units is used to demonstrate the capability of the proposed algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1633-1649
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• 2017

In remote sensing image processing, the traditional fusion algorithm is based on the Intensity-Hue-Saturation (IHS) transformation. This method does not take into account the texture or spectrum information, spatial resolution and statistical information of the photos adequately, which leads to spectrum distortion of the image. Although traditional solutions in such application combine manifold methods, the fusion procedure is rather complicated and not suitable for practical operation. In this paper, an improved IHS transformation fusion algorithm based on the local variance weighting scheme is proposed for remote sensing images. In our proposal, firstly, the local variance of the SPOT (which comes from French "Systeme Probatoire d'Observation dela Tarre" and means "earth observing system") image is calculated by using different sliding windows. The optimal window size is then selected with the images being normalized with the optimal window local variance. Secondly, the power exponent is chosen as the mapping function, and the local variance is used to obtain the weight of the I component and match SPOT images. Then we obtain the I' component with the weight, the I component and the matched SPOT images. Finally, the final fusion image is obtained by the inverse Intensity-Hue-Saturation transformation of the I', H and S components. The proposed algorithm has been tested and compared with some other image fusion methods well known in the literature. Simulation result indicates that the proposed algorithm could obtain a superior fused image based on quantitative fusion evaluation indices.

• 한국정보과학회논문지:시스템및이론
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• 제28권10호
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• pp.520-529
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• 2001

캐리-세이브 가산기(CSA)는 빠른 수행과 작은 면적을 가지는 연산 하드웨어 구현에서 가장 효과적으로 사용되는 연산 셀들 중의 하나이다. 현재 CSA 적용기술의 근복적인 약점을 그 적용이 덧셈식으로 직접 변환되는 부분에 해당되는 회로에만 가능하다는 것이다. 이러한 제한점을 극복하기위하여, 우리는 새로운 몇가지 CSA 변환 기법들을 제안한다. 구체적으로 멀티플렉서를 포함한 연산에서의 CSA 변환, 다수 회로를 포함한 연산에서의 CSA 변환, 곱셈 연산을 내포한 연산에서의 CSA 변화를 제안한다. 또한 이러한 기법들을 실제의회로 합성에서 효과적으로 적용하는 통합 알고리즘을 제안한다. 우리는 다양한 실험을 통하여 제시된 기법들에 기반한 우리의 알고리즘의 기존의 CSA 방법들과 비교하여 실제적인 회로 합성에서 매우 효율적임을 보인다.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.199-211
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• 2006

Practical automated flat pattern generation with inbuilt production features for doubly curved sheet metal components (SMCs) is addressed here utilizing a new and unique Point Transformation Algorithm (PTA). This is the third in the series of papers on practical Flat Pattern Development (FPD) [8] and Production Loft Generation Systems (PLGS) [9] complementing the pioneering work [6,7]. In the first two publications, automated loft generation programs have addressed sheet metal components having a Principal Flat Surface (PFS) only. The flat pattern development of 3-D components that do not have the flat surface(termed as Non-PFS components) having complex features of double curvature in addition to cutouts and nibbled holes typical of aircraft components were so far not addressed due to lack of relevant published algorithms. This paper traces the evolution of developments and provides the record of fully illustrated, automated loft generation scheme for aircraft SMCs including the Non-PFS components which underwent validation through production tests by sponsors. Details of some of the unique features of the system like simplified surface model generation, termed as topological model and powerful algorithms deployed with potential for CAD/CAM applications are included.

• 한국정보통신학회논문지
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• 제7권7호
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• pp.1462-1470
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• 2003

정보통신의 발달과 인터넷의 확산으로 인해 정보보안의 필요성이 증대되면서 다양한 암호알고리즘이 개발되어 활용되고 있다. 이와 더불어 암호 공격 기술도 발전하여서, 공격에 강한 알고리즘에 대한 연구가 활발하게 진행되고 있다. Substitution Permutation Networks(SPN)등의 블록 암호알고리즘에서 교환계층의 선형변환행렬이 Maximum Distance Separable(MDS) 코드를 생성하면 차분공격과 선형공격에 강한 특성을 보인다. 본 논문에서는 선형변환행렬이 MDS 코드를 생성하는가를 판단하는 새로운 알고리즘을 제안한다. 선행변환행렬의 입력코드는 GF(2$^n$)상의 원소들로 이들을 변수로 해석할 수 있다. 하나의 변수를 다른 변수들의 대수식으로 변환하고 대입하여 변수를 하나씩 소거한다. 변수가 하나이고 모든 계수가 ‘0’이 아니면 선형변환 행렬은 MDS 코드를 생성한다. 본 논문에서 제안한 알고리즘은 기존의 모든 정방부분행렬이 정칙인지를 판단하는 알고리즘과 비교하여 곱셈 및 역수 연산수를 많이 줄임으로서 수행 시간을 크게 감소 시켰다.

• 한국멀티미디어학회논문지
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• 제13권6호
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• pp.817-824
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• 2010

Linear Discriminant Analysis (LDA) has been successfully applied for dimension reduction in face recognition. However, LDA requires the transformation of a face image to a one-dimensional vector and this process can cause the correlation information among neighboring pixels to be disregarded. On the other hand, 2D-LDA uses 2D images directly without a transformation process and it has been shown to be superior to the traditional LDA. Nevertheless, there are some problems in 2D-LDA. First, it is difficult to determine the optimal number of feature vectors in a reduced dimensional space. Second, the size of rectangular windows used in 2D-LDA makes strong impacts on classification accuracies but there is no reliable way to determine an optimal window size. In this paper, we propose a new algorithm to overcome those problems in 2D-LDA. We adopt an ensemble approach which combines several classifiers obtained by utilizing various window sizes. And a practical method to determine the number of feature vectors is also presented. Experimental results demonstrate that the proposed method can overcome the difficulties with choosing an optimal window size and the number of feature vectors.

• 인터넷정보학회논문지
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• 제4권4호
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• pp.35-44
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• 2003

XML이 웹에서 사용하는 문서와 데이터의 표준이 되고 있다. XML의 문서를 정의하는데 사용되는 것이 스키마다. 이 중 마이크로소프트사가 중심이 되어 개발하고 있는 스키마인 XDR은 스키마 중에서 실제적인 활용을 주도하고 있다. UML은 객체지향 개발 방법론에서 나온 표기법으로 시스템의 구조를 나타내는데 유용한 도구이다. 본 논문은 XDR의 스키마의 구조를 UML 클래스 다이어그램으로 변환하는 방법과 알고리즘을 제안한다. 이 변환으로 XML의 문서구조를 시각화하여 XML문서의 구조를 쉽게 파악할 수 있게 되었고 재사용성과 유연성을 높여 XML문서 개발을 효율적으로 하게 하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권5호
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• pp.1708-1734
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• 2022

In the development of logistics system, the breakthrough of important technologies such as technology platform for logistics information management and control is the key content of the study. Based on Javascript and JQuery, the logistics system realizes real-time monitoring, collection of historical status data, statistical analysis and display, intelligent recommendation and other functions. In order to strengthen the cooperation of warehouse storage, enhance the utilization rate of resources, and achieve the purpose of real-time and visual supervision of transportation equipment and cargo tracking, this paper studies the VNF dynamic deployment and SFC routing problem in the network load change scenario based on the logistics system. The BIP model is used to model the VNF dynamic deployment and routing problem. The optimization objective is to minimize the total cost overhead generated by each SFCR. Furthermore, the application of the SFC mapping algorithm in the routing topology solving problem is proposed. Based on the concept of relative cost and the idea of topology transformation, the SFC-map algorithm can efficiently complete the dynamic deployment of VNF and the routing calculation of SFC by using multi-layer graph. In the simulation platform based on the logistics system, the proposed algorithm is compared with VNF-DRA algorithm and Provision Traffic algorithm in the network receiving rate, throughput, path end-to-end delay, deployment number, running time and utilization rate. According to the test results, it is verified that the test results of the optimization algorithm in this paper are obviously improved compared with the comparison method, and it has higher practical application and promotion value.