• International Journal of CAD/CAM
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• 제7권1호
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• pp.21-30
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• 2007

The inverse offset method (IOM) is widely used for generating cutter paths from the point-based surface where the surface is characterised by a set of surface points rather than parametric polynomial surface equations. In the IOM, cutter path planning is carried out by specifying the grid sizes, called the step-forward and step-interval distances respectively in the forward and transverse cutting directions. The step-forward distance causes the chordal deviation and the step-forward distance produces the cusp. The chordal deviation and cusp are also functions of local surface slopes and curvatures. As the slopes and curvatures vary over the surface, different step-forward and step-interval distances are appropriate in different areas for obtaining the machined surface accurately and efficiently. In this paper, the chordal deviation and cusp height are calculated in consideration with the surface slopes and curvatures, and their combined effect is used to estimate the machined surface error. An adaptive grid generation algorithm is proposed, which enables the IOM to generate cutter paths adaptively using different step-forward and step-interval distances in different regions rather than constant step-forward and step-interval distances for entire surface.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1153-1156
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• 2002

In this parer, a high quality mesh generation method by using interval arithmetic is proposed. In the proposed method, the variance of a tangent vector at the point is considered by the automatic differentiation. From the variance, sampling points on the surface are judged whether it is adequate or not, which is calculated by the interval arithmetic. Then Delaunay triangulation is performed to the obtained sampling points, and a set of meshes is generated. The proposed method is hard to overlook the local variation of surfaces.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
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• pp.53-58
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• 2009

Solar photovoltaic power generation system is judging that by the most suitable new refreshing energy in real condition of our country forward continuously interest for solar photovoltaic power generation system and diffusion me enlarged. Output decline problem is item to consider necessarily and should be verified in continuous interest for solar photovoltaic power generation system are diffusion. Present plan that minimize output decline calculating module liver optimum interval that consider recitation of a poem to reduce output decline by module liver shade by incidence angle consideration and this that occupy most parts among factor because do output of solar photovoltaic power generation system well.

• 한국산업융합학회 논문집
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• 제26권3호
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• pp.401-409
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• 2023

Oscillating water column (OWC) type wave power generator system is a power generation system that uses wave energy, a sustainable and renewable energy source. Irregular cycles and wave heights act as factors that make it difficult to secure generation efficiency of the wave power generator system. Recently, research for improving power generation efficiency is being conducted by applying digital twin technology to OWC type wave energy converter system. However, digital twin using sensor data can predict erroneous performance due to uncertainty in the sensor data. Therefore, this study proposes an uncertainty analysis method for sensor data which is used in digital twin to secure the reliability of digital twin prediction results. Uncertainty quantification considering sensor data characteristics and future uncertainty information according to uncertainty propagation were derived mathematically, and confidence interval estimation was performed based on the proposed method.

• International Journal of Internet, Broadcasting and Communication
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• 제13권3호
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• pp.34-41
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• 2021

Recently, a lossless non-successive interference cancellation (SIC) non-orthogonal multiple access (NOMA) implementation has been proposed. Such lossless NOMA without SIC is achieved via correlated superposition coding (SC), in comparison with conventional independent SC. However, only high-correlated SC was investigated in the lossless non-SIC NOMA implementation. Thus, this paper investigates low-correlated SC, especially a lossless interval, owing to low-correlation between signals. First, for the low-correlated SC scheme, we derive the closed-form expressions for the two roots with which the lossless interval is defined. Then, simulations demonstrate that the lossless interval of low-correlated SC NOMA is enlarged, with a degraded middle interval, compared to that of high-correlated SC NOMA. Moreover, we also show that such tendency becomes stronger as the value of the correlation coefficient varies. As a result, the proposed low-correlated SC scheme could be considered as a promising correlated SC scheme, with the enlarged lossless interval in NOMA toward the future sixth-generation (6G) ultra-reliable low-latency communications (URLLC).

• 한국군사과학기술학회지
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• 제14권5호
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• pp.859-870
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• 2011

The purpose of this paper is to develop reliability analysis procedures for repairable systems with interval failure time data and apply the procedures for assessing the storage reliability of a subsystem of a certain type of guided missile. In the procedures, the interval failure time data are converted to pseudo failure times using the uniform random generation method, mid-point method or equispaced intervals method. Then, such analytic trend tests as Laplace, Lewis-Robinson, Pair-wise Comparison Nonparametric tests are used to determine whether the failure process follows a renewal or non-renewal process. Monte Carlo simulation experiments are conducted to compare the three conversion methods in terms of the statistical performance for each trend test when the underlying process is homogeneous Poisson, renewal, or non-homogeneous Poisson. The simulation results show that the uniform random generation method is best among the three. These results are applied to actual field data collected for a subsystem of a certain type of guided missile to identify its failure process and to estimate its mean time to failure and annual mean repair cost.

• 한국멀티미디어학회논문지
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• 제10권8호
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• pp.945-957
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• 2007

수량 연관규칙은 대량의 데이터베이스에 존재하는 데이터 중 수량적 속성이 강한 데이터를 항목으로 만들어 이진 연관규칙에 적용한다. 만약 중요한 의미를 내포하는 수량 데이터의 정의역 범위가 넓을 경우 정의역을 최소지지도에 만족하는 적정 구간으로 분할하여 빈발구간 항목을 생성하는 작업이 필요하다. 이러한 빈발구간 항목은 어떻게 생성되었느냐에 따라 생성된 규칙의 신뢰도에 큰 영향을 미치게 된다. 따라서 본 논문에서는 빈발구간 항목을 효율적으로 생성하는 방법을 제시한다. 본 논문에서 제안하는 방법은 기존 방법들에 비해 의미가 있는 구간을 분실하지 않고 최소지지도에 근접하는 세밀한 빈발구간을 생성하기 때문에 데이터가 가진 특성의 손실을 최소화할 수 있는 효율적인 방법이다. 또한 병합이 불필요한 곳에서는 병합을 시도하지 않고 빈도가 높은 구간만을 취해 병합하므로 수량의 정의역이 넓을 경우 기존 방법에 비해 실행속도가 월등히 빠른 효율적인 방법이다. 그리고 인구센서스와 같은 실제로 사용되는 데이터를 이용하여 클루닉스 HPC 시스템에서 병렬처리 수행을 통하여 제안 방법이 우수함을 보였다.

• 한국지능시스템학회논문지
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• 제26권3호
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• pp.233-238
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• 2016

본 논문은 차세대 침입탐지 시스템을 위해서 데이터 융합에서의 불확실한 데이터 처리의 알고리즘을 제안한다. 차세대 침입탐지는 사이버 공간에서 생성되어지는 정보를 지식으로 만들어내기 위해 수많은 네트워크 센서로부터의 데이터가 수집되어진다. 수집된 센서 정보를 지식의 수준으로 이끌어내기 위해서 데이터 융합의 과정이 필요하다. 이를 위해 본 논문에서는 Demster-Shafer 증거이론 추론적 기법을 통하여 서로 다른 데이터들의 특징을 분석하여 불확실한 데이터가 어느 구간에서 신뢰구간을 갖는지를 분류하여, 불확실한 데이터에 대한 표현을 이루어낸다. 본 실험내용에서는 이러한 불확실성 데이터에 대한 이상탐지를 위해 iris plant 데이터세트를 이용한 신뢰구간에 따른 분류를 실행하였다. 이에 대해 각 신뢰구간을 통해서 데이터 분류가 가능하다는 것을 검증하였다.

• Smart Structures and Systems
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• 제26권3호
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• pp.311-318
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• 2020

The goal of this study is to analytically and non-stochastically generate structural uncertainty behaviors of isotropic beams and laminated composite plates under plane stress conditions by using an interval finite element method. Uncertainty parameters of structural properties considering resistance and load effect are formulated by interval arithmetic and then linked to the finite element method. Under plane stress state, the isotropic cantilever beam is modeled and the laminated composite plate is cross-ply lay-up [0/90]. Triangular shape with a clamped-free boundary condition is given as geometry. Through uncertainties of both Young's modulus for resistance and applied forces for load effect, the change of structural maximum deflection and maximum von-Mises stress are analyzed. Numerical applications verify the effective generation of structural behavior uncertainties through the non-stochastic approach using interval arithmetic and immediately the feasibility of the present method.

• 대한음성학회지:말소리
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• 제25_26호
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• pp.52-64
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• 1993

This paper aims to explore the rhythmic phenomena of standard Korean by an experimental phonetic method. A total of 16 informants taking part in this experiment were divided into four groups : old males(OM) and old females(OF) in their fifties and young males(YM) and young females(YF) in their twenties. The informants were asked to read speech data consisting of two rhythmic units, each of which began with a stressed syllable with a long wowel. Starting with the frame / 'ma:1 'ma:nta /, the first rhythmic unit was expanded up to five syllables in all while keeping the second rhythmic unit constant with a view to investigate the pattern of increase in the interstress time interval. The results of this study are as follows: 1. There is a considerable difference between yen and old generations with respect to the duration of interstress interval . The young generation tends to speak faster than the old generation. This observation is supported by difference in the interstress intervals as exhibited by OM(389.66), OF(473), YM(275.55), YF(285.83) in the test frame '말 많다' ['ma:1 'ma:nta]. 2. Young and old generations showed a different tendency in the increase rate of duration between mono-syllables and polysyllables. In other words, the rhythm of young generation shows the tendency of syllable-timed language whereas that of old generation clearly leans towards the stressed-timed language.