• 품질경영학회지
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• 제24권4호
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• pp.207-223
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• 1996

These days, customers have attached great importance to the function of product liability and quality assurance. In Korea, the single rectifying sampling inspection for attribute (KS A 3105) has been used. But this inspection plan given by tables (KS A 3105) has some defects. There are limitations in the range of applications and irrationality of approximate probability and the double rectifying sampling inspection is not mentioned. Moreover, ATI (average total inspection) does not reflect sampling costs and the loss of nonconforming item. Therefore, the objectives of this study is to develope new algorithms and computer program that provide the optimal sampling inspection plan based on minimum linear costs (single & double inspection plan). The result of this study revealed that the new algorithm is less than KS A 3105 in ATI and basically, double inspection plan is more economical. Also it comes over restrictions in KS A 3105. So, it is definite that the optimal solution can be obtained considering cost factors in manufacturing and sampling process, and costs can be saved in the long term.

• Journal of Mechanical Science and Technology
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• 제14권8호
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• pp.807-815
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• 2000

In this paper, modified discrete time preview control algorithms for active and semi-active suspension systems are derived based on a simple mathematical 4 DOF half-car model. The discrete time preview control laws for ride comfort are employed in the simulation. The algorithms for MIMO system contain control strategies reacting against body forces that occur at cornering, accelerating, braking, or under payload, in addition to road disturbances. Matlab simulation results for the discrete time case are compared with those for the continuous time case and the appropriateness of the discrete time algorithms are verified by the of simulation results. Passive, active, and semi-active system responses to a sinusoidal input and an asphalt road input are analysed and evaluated. The simulation results show the extent of performance degradation due to numerical errors related to the length of the sampling time and time delay.

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.274-281
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• 2013

In this study, we consider the challenges in motion planning for automated driving systems. Most of the existing online motion-planning algorithms, which take dynamics into account, find it difficult to operate in an environment with narrow passages. Some of the existing algorithms overcome this by offline preprocessing if environment is known. In this work an online algorithm for motion planning with dynamics in an unknown cluttered environment with narrow passages is presented. It utilizes an idea of hybrid planning with sampling- and discretization-based motion planners, which run simultaneously in a full configuration space and a derived reduced space. The proposed algorithm has been implemented and tested with a real autonomous vehicle. It provides significant improvements in computational time performance over basic planning algorithms and allows the generation of smoother paths than those generated by the recently developed hybrid motion planners.

• 대한원격탐사학회지
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• 제25권4호
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• pp.321-338
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• 2009

이 연구의 목적은 비대칭 분포를 가지는 현장 조사 자료로부터 GIS 기반 주제도를 생성하기 위한 공간 내삽 방법으로 단변량 크리깅 기법을 비교하는데 있다. 기존 정규 크리깅과 비선형 자료 변환에 기반을 둔 로그 정규 크리깅, 다중 가우시안 크리깅과 지시자 크리깅을 지화학 원소 비소와 납에 대해 사례 연구를 통해 비교하였다. 예측 능력의 비교 분석을 위해 leave-one-out 기반 교차 검증을 통한 오차 분석을 수행하였으며, 샘플링 밀도의 차이에 따른 오차의 변화 양상도 분석하였다. 비교 분석 결과, 지시자 크리깅이 전반적으로 가장 높은 예측 능력을 나타내었으며, 작은 값과 높은 값의 예측 능력도 우수한 것으로 나타났다. 정규 크리깅에 비해 비선형 자료 변환 기반 크리깅 기법들이 우수한 예측 능력을 나타내었지만, 기존에 많이 적용된 로그 정규 크리깅은 샘플링 밀도와 상관없이 편향 정도가 가장 크게 나타내었다. 이 연구를 통해 얻어지는 정량적 검증 결과는 비대칭 분포를 가지는 현장 조사 자료의 내삽을 위한 크기깅 기법의 선정에 유용하게 이용될 수 있을 것으로 기대된다.

• Journal of Power Electronics
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• 제16권1호
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• pp.227-237
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• 2016

A novel digital current control strategy for digitally controlled DC-DC switching converters, referred to as Adjacent Cycle Sampling (ACS), is proposed in this paper. For the ACS current control strategy, the available time interval from sampling the current to updating the duty ratio, is approximately one switching cycle. In addition, it is independent of the duty ratio. As a result, the contradiction between the processing speed of the hardware and the transient response speed can be effectively relaxed by using the ACS current control strategy. For digitally controlled buck DC-DC switching converters with trailing-edge modulation, digital current control algorithms with the ACS control strategy are derived for three different control objectives. These objectives are the valley, average, and peak inductor currents. In addition, the sub-harmonic oscillations of the above current control algorithms are analyzed and eliminated by using the digital slope compensation (DSC) method. Experimental results based on a FPGA are given, which verify the theoretical analysis results very well. It can be concluded that the ACS control has a faster transient response speed than the time delay control, and that its requirements for hardware processing speed can be reduced when compared with the deadbeat control. Therefore, it promises to be one of the key technologies for high-frequency DC-DC switching converters.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권5호
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• pp.331-337
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• 2004

Target motion analysis with a sonar system in general uses a regular sampling time and thus obtains regular target information regardless of the target maneuver status. This often results in overconsumption of the limited sonar resources. We propose two methods of the IMM(interacting Multiple Model) PDAF algorithm for sonar resource management to improve target motion analysis performance and to save sonar resources in this paper. In the first method, two different process noise covariance which are used as mode sets are combined based on probability. In the second method, resource time which are processed from two mode sets is calculated based on probability and then considered as update time at next step. Performance of the proposed algorithms are compared with the other algorithms by a series of Monte Carlo simulation.

• 지능정보연구
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• 제13권3호
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• pp.31-45
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• 2007

대용량의 데이터 처리에 관한 문제는 데이터 마이닝 내 중요한 이슈 중의 하나이다. 특히 데이터 클러스터링과 같이 컴퓨터 시뮬레이션으로 인한 부하가 큰 경우 더더욱 그러하다. 그러나 대개 이러한 문제는 Random sampling 으로 어느 정도 해결이 가능하다. 문제는 이런 샘플링을 통해서 발생하는 noise의 해결이다. 본 논문에서는 그러한 noise문제를 극복할 수 있도록 설계된 새로운 데이터클러스터링 알고리즘을 소개한다. 기존의 데이터 클러스팅 알고리즘과의 컴퓨터 비교 실험을 통해 본 알고리즘의 우수성을 밝혔으며 아울러 더 나아가 데이터 set의 일부만을 사용한 시뮬레이션 결과를 통해, 해의 정확도와 상관없이 실험 시간 또한 단축되었음을 보여주고 있다.

• 디지털산업정보학회논문지
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• 제11권1호
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• pp.171-182
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• 2015

The general wavelet transform has profitable property in non-stationary signal analysis specially. The tunable Q-factor wavelet transform is a fully-discrete wavelet transform for which the Q-factor Q and the asymptotic redundancy r, of the transform are easily and independently specified. In particular, the specified parameters Q and r can be real-valued. Therefore, by tuning Q, the oscillatory behavior of the wavelet can be chosen to match the oscillatory behavior of the signal of interest, so as to enhance the sparsity of a sparse signal representation. The TQWT is well suited to fast algorithms for sparsity-based inverse problems because it is a Parseval frame, easily invertible, and can be efficiently implemented. The transform is based on a real valued scaling factor and is implemented using a perfect reconstruction over-sampled filter bank with real-valued sampling factors. The transform is parameterized by its Q-factor and its over-sampling rate, with modest over-sampling rates being sufficient for the analysis/synthesis functions to be well localized. This paper describes filter design of 2D discrete-time wavelet transform for which the Q-factor is easily specified. With the advantage of this transform, perfect reconstruction filter design and implementation for performance improvement are focused in this paper. Hence, the 2D transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. Therefore, application for performance improvement in multimedia communication field was evaluated.

• 정보보호학회논문지
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• 제34권2호
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• pp.167-177
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• 2024

본 논문은 isogeny 기반 전자 서명 알고리즘인 SeaSign의 최적화 방안을 제안한다. SeaSign은 CSIDH의 class group action에 Fiat-Shamir with abort를 결합한 전자서명 알고리즘이다. CSIDH 기반 암호는 SIDH 기반 암호가 다항시간안에 공격됨에 따라 다시 주목받고 있지만, 이를 기반한 전자서명인 SeaSign은 비효율적인 속도로 많은 최적화가 진행되지 않았다. 본 논문에서는 SeaSign에 대한 효율적인 서명 방법을 제안한다. 제안하는 서명 방법은 간단하지만 강력하며, 알고리즘 내에서 rejection sampling의 위치 변경을 통해 이루어진다. 추가로, 본 논문에서는 제안하는 알고리즘이 최적 성능을 제공할 수 있는 파라미터를 제시한다. 제시한 결과, 기존 SeaSign의 파라미터를 사용할 경우, 본 논문에서 제안한 서명방법은 기존 SeaSign 대비 3배 빠른 성능을 보인다. 추가로 신규 제시된 파라미터와 본 논문의 서명 방법을 결합한 경우, 기존 SeaSign 대비 290배 빠른 성능과 Decru 등이 제안한 방법 대비 7.47배 빠른 성능을 제공한다.

• Journal of Power Electronics
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• 제16권2호
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• pp.717-730
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• 2016

The harmonic components of grid voltage result in oscillations of the calculated phase obtained via phase synchronization. This affects the security and stability of grid-connected converters. Moving average filter, delayed signal cancellation and their related harmonic elimination algorithms are major methods for such issues. However, all of the existing methods have their limitations in dealing with multiple harmonics issues. Furthermore, few studies have focused on a comparison and evaluation of these algorithms to achieve optimal algorithm selections in specific applications. In this paper, these algorithms are quantitatively analyzed based on the derived mathematical models. Moreover, an enhanced moving average filter and enhanced delayed signal cancellation algorithms, which are applicable for eliminating a group of selective harmonics with only one calculation block, are proposed. On this basis, both a comprehensive comparison and a quantitative evaluation of all of the aforementioned algorithms are made from several aspects, including response speed, required data storage size, sensitivity to sampling frequency, and elimination of random noise and harmonics. With the conclusions derived in this paper, better overall performance in terms of harmonic elimination can be achieved. In addition, experimental results under different conditions demonstrate the validity of this study.