• Title/Summary/Keyword: Redundancy analysis

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Fault Detection System Design and HILS Evaluation for the Smart UAV FCS

  • Nam, Yoon-Su;Jang, Hu-Yeong;Hong, Sung-Kyung;Park, Sung-Su
    • International Journal of Control, Automation, and Systems
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    • v.5 no.1
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    • pp.104-109
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    • 2007
  • This paper is about a redundancy management system design for the Smart UAV(unmanned aerial vehicle) which utilizes the tilt..rotor mechanism. In order to meet the safety requirement on the PLOC(probability of loss of control) of $1.7{\times}10^{-5}$ per flight hour for FCS (flight control system) failures, a digital FCS is mechanized with a dual redundant structure. A fault detection system which is composed of a CCM(cross channel monitor) and analytic redundancy using the Kalman filtering is designed, and its effectiveness is evaluated through experiments. A threshold level and persistence count for managing redundant sensors are designed based on the statistical analysis of the FCS sensors. To increase the survivability of the UAV after the loss of critical sensors in the SAS(stability augmentation system) and to provide reference information for a tie-breaking condition at which an ILM(in-line monitor) cannot distinguish the faulty channel between two operating ones, the Kalman filter approach is investigated.

A Study on the Relationship between R&D Culture and Job Involvement in Information Technology Industries (정보기술산업의 R&D 문화와 직무몰입에 관한 연구)

  • Lee, Sun-Kyu;Lee, Ung-Hee;Jeon, Ki-Sang;Han, Soo-Deok
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.3
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    • pp.103-110
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    • 2006
  • This paper aims to examine the main factors of the organizational climate and analyze their effects on job involvement. To accomplish these purposes, the nam factors of the organizational climate such as diversity, autonomy, redundancy, connectivity and flexibility were found from the previous studies. The questionaries of 350 were distributed to the employees working at the Gumi Industrial Complex. The questionaries of 298 were obtained and 267 were analyzed through frequencies, correlation and multiple regression. The results of this study are as followings; First, we conducted exploratory factor analysis for five constructs(diversity, autonomy, redundancy, connectivity and flexibility) using oblique rotation method that did not assume independence among the factors and main factors of knowledge management were grouped together by five factors. Second, it is shown that four main factors of organizational climate have a positive influence on the job involvement(p<0.05). This study, however, have limitations of number of sample and survey area. The future study should consider these limitations in improving model applicability in practice.

Digital Image Processing Using Tunable Q-factor Discrete Wavelet Transformation (Q 인자의 조절이 가능한 이산 웨이브렛 변환을 이용한 디지털 영상처리)

  • Shin, Jong Hong
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.10 no.3
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    • pp.237-247
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    • 2014
  • This paper describes a 2D discrete-time wavelet transform for which the Q-factor is easily specified. Hence, the transform can be tuned according to the oscillatory behavior of the image signal to which it is applied. The tunable Q-factor wavelet transform (TQWT) is a fully-discrete wavelet transform for which the Q-factor, Q, of the underlying wavelet and the asymptotic redundancy (over-sampling rate), 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 TQWT can also be used as an easily-invertible discrete approximation of the continuous wavelet transform. The transform is based on a real valued scaling factor (dilation-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 oversampling rate (redundancy), with modest oversampling rates (e. g. 3-4 times overcomplete) being sufficient for the analysis/synthesis functions to be well localized. Therefore, This method services good performance in image processing fields.

A Clustering Approach for Feature Selection in Microarray Data Classification Using Random Forest

  • Aydadenta, Husna;Adiwijaya, Adiwijaya
    • Journal of Information Processing Systems
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    • v.14 no.5
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    • pp.1167-1175
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    • 2018
  • Microarray data plays an essential role in diagnosing and detecting cancer. Microarray analysis allows the examination of levels of gene expression in specific cell samples, where thousands of genes can be analyzed simultaneously. However, microarray data have very little sample data and high data dimensionality. Therefore, to classify microarray data, a dimensional reduction process is required. Dimensional reduction can eliminate redundancy of data; thus, features used in classification are features that only have a high correlation with their class. There are two types of dimensional reduction, namely feature selection and feature extraction. In this paper, we used k-means algorithm as the clustering approach for feature selection. The proposed approach can be used to categorize features that have the same characteristics in one cluster, so that redundancy in microarray data is removed. The result of clustering is ranked using the Relief algorithm such that the best scoring element for each cluster is obtained. All best elements of each cluster are selected and used as features in the classification process. Next, the Random Forest algorithm is used. Based on the simulation, the accuracy of the proposed approach for each dataset, namely Colon, Lung Cancer, and Prostate Tumor, achieved 85.87%, 98.9%, and 89% accuracy, respectively. The accuracy of the proposed approach is therefore higher than the approach using Random Forest without clustering.

Supervised-learning-based algorithm for color image compression

  • Liu, Xue-Dong;Wang, Meng-Yue;Sa, Ji-Ming
    • ETRI Journal
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    • v.42 no.2
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    • pp.258-271
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    • 2020
  • A correlation exists between luminance samples and chrominance samples of a color image. It is beneficial to exploit such interchannel redundancy for color image compression. We propose an algorithm that predicts chrominance components Cb and Cr from the luminance component Y. The prediction model is trained by supervised learning with Laplacian-regularized least squares to minimize the total prediction error. Kernel principal component analysis mapping, which reduces computational complexity, is implemented on the same point set at both the encoder and decoder to ensure that predictions are identical at both the ends without signaling extra location information. In addition, chrominance subsampling and entropy coding for model parameters are adopted to further reduce the bit rate. Finally, luminance information and model parameters are stored for image reconstruction. Experimental results show the performance superiority of the proposed algorithm over its predecessor and JPEG, and even over JPEG-XR. The compensation version with the chrominance difference of the proposed algorithm performs close to and even better than JPEG2000 in some cases.

A Compliance Control Method for Robot Hands with Consideration of Decoupling among Fingers/Joints (손가락/관절 간의 기구학적 독립을 고려한 로봇 손의 컴플라이언스 제어 방법)

  • Kim, Byoung-Ho;Yi, Byung-Ju;Suh, Il-Hong;Oh, Sang-Rok
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.7
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    • pp.568-577
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    • 2000
  • In this paper for an object grasped by a robot hand to work in stiffness control domain we first investigate the number of fingers for successful stiffness modulation in the object operational space. Next we propose a new compliance control method for robot hands which consist of two steps. RIFDS(Resolved Inter-Finger Decoupling Solver) is to decompose the desired compliance characteristic specified in the op-erational space into the compliance characteristic in the fingertip space without inter-finger coupling and RIJDS(Resolved Inter-Joint Decoupling Solver) is to decompose the fingertip space without inter-finger coupling and RIJDS(Resolved inter-Joint Decoupling Solver) is to decompose the compliance characteristic in the finger-tip space into the compliance characteristic given in the joint space without inter-joint coupling. Based on the analysis results the finger structure should be biominetic in the sense that either kniematic redundancy or force redundancy are required to implement the proposed compliance control scheme, Five-bar fingered robot hands are used as an illustrative example to implement the proposed compliance control method. To show the effectiveness of the proposed compliance control method simulations are performed for two-fingered and three-fingered robot hands.

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Analysis of singularity and redundancy control for robot-positioner system (로봇과 포지셔너 시스템의 특이성 분석과 여유 자유도 제어)

  • 전의식;장재원;서일홍;오재응;염성하
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.6
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    • pp.1252-1264
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    • 1988
  • Recently industrial robots together with positioners are often used to enhance the system performance for arc welding. In this paper, a redundancy control method is proposed to the robot-positioner system with seven degrees of freedom, where one kinematic modelling technique is employed. Also, manipulability in the given cutting plane of the workspace. An algorithm maximizing the manipulability is applied to the robot and the positioner and the simulation results are shown for the task following a linear path.

An Optimal ODAM-Based Broadcast Algorithm for Vehicular Ad-Hoc Networks

  • Sun, Weifeng;Xia, Feng;Ma, Jianhua;Fu, Tong;Sun, Yu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.12
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    • pp.3257-3274
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    • 2012
  • Broadcast routing has become an important research field for vehicular ad-hoc networks (VANETs) recently. However, the packet delivery rate is generally low in existing VANET broadcast routing protocols. Therefore, the design of an appropriate broadcast protocol based on the features of VANET has become a crucial part of the development of VANET. This paper analyzes the disadvantage of existing broadcast routing protocols in VANETs, and proposes an improved algorithm (namely ODAM-C) based on the ODAM (Optimized Dissemination of Alarm Messages) protocol. The ODAM-C algorithm improves the packet delivery rate by two mechanisms based on the forwarding features of ODAM. The first distance-based mechanism reduces the possibility of packet loss by considering the angles between source nodes, forwarding nodes and receiving nodes. The second mechanism increases the redundancy of forwarding nodes to guarantee the packet success delivery ratio. We show by analysis and simulations that the proposed algorithm can improve packet delivery rate for vehicular networks compared against two widely-used existing protocols.

A Novel Algorithm for Fast Node-search and Redundancy Reduction in Gossip-based P2P Network (빠른 노드 검색과 부하감소를 위한 새로운 가쉽기반 P2P 네트워크 알고리즘)

  • Zhu, Xiao-Wei;Jang, Kyung-Sik
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.619-622
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    • 2009
  • P2P networks are undergoing rapid progress and inspiring numerous developments by gossip-based protocol. Gossip-based protocols for group communication have attractive scalability and reliability properties. We propose a self-organizing algorithm in the sense that the size of neighbor list achieved without any node knowing the group size. We also propose an efficient mechanism to reduce the redundancy of the system by backing up the nodes in the neighbor list. We present the design, theoretical analysis, and a detailed evaluation of the proposed algorithm and its refinements.

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A Study on the Achievement of Required Safety Integrity Level to Reduce Risk for SMR On-Site Hydrogen Refueling Stations (개질형 On-Site 수소충전소의 리스크 감소를 위해 요구되는 SIL 등급 달성 방안에 관한 연구)

  • Lee, Jin Ho;Lim, Jae-Yong
    • Journal of the Korean Society of Safety
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    • v.35 no.6
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    • pp.1-8
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    • 2020
  • In recent years, hydrogen has received much attention as an alternative energy source to fossil fuels. In order to ensure safety from the increasing number of hydrogen refueling stations, prevention methods have been required. In this regard, this study suggested an approach to reduce the risk of hydrogen refueling station by increasing Safety Integrity Level (SIL) for a Steam Methane Reformer (SMR) in On-Site Hydrogen Refueling Station. The worst scenario in the SMR was selected by HAZOP and the required SIL for the worst scenario was identified by LOPA. To verify the required SIL, the PFDavg.(1/RRF) of Safety Instrumented System (SIS) in SMR was calculated by using realistic failure rate data of SIS. Next, several conditions were tested by varying the sensor redundancy and proof test interval reduction and their effects on risk reduction factor were investigated. Consequently, an improved condition, which were the redundancy of two-out-of-three and the proof test interval of twelve months, achieved the tolerable risk resulting in the magnitude of risk reduction factor ten times greater than that of the baseline condition.