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Implementation of Envelope Analysis on a Wireless Condition Monitoring System for Bearing Fault Diagnosis

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International Journal of Automation and computing 2015年第1期12卷 14-24页

作者： Guo-Jin Feng James Gu Dong Zhen Mustafa Aliwan Feng-Shou Gu Andrew D.Ball school of Computing and Engineering University of Huddersfield school of Engineering Manchester Metropolitan University

Envelope analysis is an effective method for characterizing impulsive vibrations in wired condition monitoring(CM)systems. This paper depicts the implementation of envelope analysis on a wireless sensor node for obtaining a more convenient and reliable CM system. To maintain CM performances under the constraints of resources available in the cost effective Zigbee based wireless sensor network(WSN), a low cost cortex-M4 F microcontroller is employed as the core processor to implement the envelope analysis algorithm on the sensor node. The on-chip 12 bit analog-to-digital converter(ADC) working at 10 k Hz sampling rate is adopted to acquire vibration signals measured by a wide frequency band piezoelectric accelerometer. The data processing flow inside the processor is optimized to satisfy the large memory usage in implementing fast Fourier transform(FFT) and Hilbert transform(HT). Thus, the envelope spectrum can be computed from a data frame of 2048 points to achieve a frequency resolution acceptable for identifying the characteristic frequencies of different bearing faults. Experimental evaluation results show that the embedded envelope analysis algorithm can successfully diagnose the simulated bearing faults and the data transmission throughput can be reduced by at least 95% per frame compared with that of the raw data, allowing a large number of sensor nodes to be deployed in the network for real time monitoring.

关键词： Wireless sensor network(WSN) envelope analysis fault diagnosis local processing Hilbert transformation

Potentials and challenges of using co-design in health services research in low-and middle-income countries

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Global Health Research and Policy 2023年第1期8卷 514-521页

作者： Devendra Raj Singh Rajeeb Kumar Sah Bibha Simkhada Zoe Darwin school of Human and Health Sciences University of HuddersfieldHuddersfieldUK

Co-design with people having poor access to health services and fragile health systems in low-and middle-income countries can be momentous in bringing service users and other stakeholders together to improve the delivery and utilisation of health *** is ample of evidence from high-income countries regarding how co-design can translate available evidence into developing acceptable,feasible,and adaptable health solutions in different ***,there is limited literature on co-design in health research in the context of low-and middle-income ***,it is crucial to understand how knowledge about collaborative working can be translated into policy and practice in the context of low-and middle-income ***,this paper discusses the concept of co-design,co-production,and co-creation in health and the potentiality and challenges of using co-design in health services research in low-and middle-income *** the challenges,the co-design research has considerable potential to encourage the meaningful engagement of service users and other stakeholders in developing,implementing,and evaluating real-world solutions in low-and middle-income *** is essential to balance power dynamics in a co-design process through mutual recognition and respect,participant diversity,and reciprocity and flexibility in *** inclusive and collaborative approach to working is complex due to existing rigid hierarchical structures,socio-cultural beliefs,political interference and working ***,this could be minimised by developing transparent terms of reference that reflect the value and benefits of equal partnership in particular co-design work.

关键词： Co-design Potentials Challenges Health services research Low-middle-income countries

Video Analysis Based on Volumetric Event Detection

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International Journal of Automation and computing 2010年第3期7卷 365-371页

作者： Jing Wang Zhi-Jie Xu Department of Informatics School of Computing and Engineering University of Huddersfield Huddersfield HD1 3DH UK

During the past decade, feature extraction and knowledge acquisition based on video analysis have been extensively researched and tested on many applications such as closed-circuit television （CCTV） data analysis, large-scale public event control, and other daily security monitoring and surveillance operations with various degrees of success. However, since the actual video process is a multi-phased one and encompasses extensive theories and techniques ranging from fundamental image processing, computational geometry and graphics, and machine vision, to advanced artificial intelligence, pattern analysis, and even cognitive science, there are still many important problems to resolve before it can be widely applied. Among them, video event identification and detection are two prominent ones. Comparing with the most popular frame-to-frame processing mode of most of today＇s approaches and systems, this project reorganizes video data as a 3D volume structure that provides the hybrid spatial and temporal information in a unified space. This paper reports an innovative technique to transform original video frames to 3D volume structures denoted by spatial and temporal features. It then highlights the volume array structure in a so-called ＂pre-suspicion＂ mechanism for a later process. The focus of this report is the development of an effective and efficient voxel-based segmentation technique suitable to the volumetric nature of video events and ready for deployment in 3D clustering operations. The paper is concluded with a performance evaluation of the devised technique and discussion on the future work for accelerating the pre-processing of the original video data.

关键词： Spatio-temporal volume (STV) video processing volume feature extraction segmentation motion analysis.

Creeper:a tool for detecting permission creep in file system access controls

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Cybersecurity 2019年第1期2卷 239-252页

作者： Simon Parkinson Saad Khan James Bray Daiyaan Shreef Department of Computer Science School of Computing and EngineeringUniversity of HuddersfieldQueensgateHD13DHHuddersfieldUK

Access control mechanisms are widely used in multi-user IT systems where it is necessary to restrict access to computing *** is certainly true of file systems whereby information needs to be protected against unintended *** permissions often evolve over time,and changes are often made in an ad hoc manner and do not follow any rigorous *** is largely due to the fact that the structure of the implemented permissions are often determined by experts during initial system configuration and documentation is rarely ***,permissions are often not audited due to the volume of information,the requirement of expert knowledge,and the time required to perform manual *** paper presents a novel,unsupervised technique whereby a statistical analysis technique is developed and applied to detect instances of permission *** system(herein refereed to as Creeper)has initially been developed for Microsoft systems;however,it is easily extensible and can be applied to other access control *** analysis has demonstrated good performance and applicability on synthetic file system permissions with an average accuracy of 96%.Empirical analysis is subsequently performed on five real-world systems where an average accuracy of 98%is established.

关键词： Permission creep Access control Auditing χ^2 statistics

Feature Selection by Merging Sequential Bidirectional Search into Relevance Vector Machine in Condition Monitoring

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1248-1253页

作者： ZHANG Kui DONG Yu BALL Andrew school of Economics & Management Wuhan Polytechnic University school of Information Engineering Communication University of China school of Computing & Engineering University of Huddersfield

For more accurate fault detection and diagnosis, there is an increasing trend to use a large number of sensors and to collect data at high frequency. This inevitably produces large-scale data and causes difficulties in fault classification. Actually, the classification methods are simply intractable when applied to high-dimensional condition monitoring data. In order to solve the problem, engineers have to resort to complicated feature extraction methods to reduce the dimensionality of data. However, the features transformed by the methods cannot be understood by the engineers due to a loss of the original engineering meaning. In this paper, other forms of dimensionality reduction technique（feature selection methods） are employed to identify machinery condition, based only on frequency spectrum data. Feature selection methods are usually divided into three main types： filter, wrapper and embedded methods. Most studies are mainly focused on the first two types, whilst the development and application of the embedded feature selection methods are very limited. This paper attempts to explore a novel embedded method. The method is formed by merging a sequential bidirectional search algorithm into scale parameters tuning within a kernel function in the relevance vector machine. To demonstrate the potential for applying the method to machinery fault diagnosis, the method is implemented to rolling bearing experimental data. The results obtained by using the method are consistent with the theoretical interpretation, proving that this algorithm has important engineering significance in revealing the correlation between the faults and relevant frequency features. The proposed method is a theoretical extension of relevance vector machine, and provides an effective solution to detect the fault-related frequency components with high efficiency.

关键词： feature selection relevance vector machine sequential bidirectional search fault diagnosis

Modeling and applying credible interval intuitionistic fuzzy reciprocal preference relations in group decision making

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Journal of Systems Engineering and Electronics 2017年第2期28卷 301-314页

作者： Wei Zhou Zeshui Xu business school Sichuan University International business school Yunnan University of Finance and Economics

Intuitionistic fuzzy preference relations are powerful techniques used to express uncertain preference information. However, simultaneously providing the exact priority and non-priority intensities could be difficult in real applications. A credible interval intuitionistic fuzzy number (CIIFN) is introduced and a credible interval intuitionistic fuzzy reciprocal preference relation (CIIFRPR) is developed to solve this issue. Unlike intuitionistic fuzzy preference relations, the new preference relations use the CIIFNs to express the preference information such that the decision makers simply provide the priority intensity with interval-valued numbers and calculate the non-preference intensity with the transformed method, which avoids a complex evaluation of non-priority information. Furthermore, some basic operations and comparison laws are investigated, based on which three credible interval intuitionistic fuzzy aggregation operators are proposed. Two models are presented to manage the group decision-making. Finally, a practical case is used to demonstrate the feasibility and reasonability of the proposed preference relations and aggregation operators. © 2017 Beijing Institute of Aerospace Information.

关键词： Fuzzy rules Fuzzy sets Mathematical operators

CAPACITY COMMITMENT AND PRICING FOR SUBSTITUTABLE PRODUCTS UNDER COMPETITION

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Journal of Systems Science and Systems Engineering 2012年第4期21卷 443-460页

作者： Hongyan LI Tianhui YOU business and Social Science school Aarhus University school of business Administration Northeastern University

Capacity acquisition and pricing decisions are a company＇s long-term strategic decisions. However, demand uncertainty and substitutability of multiple products cause the difficulty to solve capacity and pricing decision problems. In this paper, we address a multiple product pricing and multiple resource capacity acquisition problem with *** and competition. The company needs to determine capacity commitment for each resource and product prices before demands are realized so that the total profit is maximized. If the demand exceeds the committed capacity, extra amounts can be purchased from the spot market. Variable unit production costs, capacity acquisition and maintenance costs are considered. We first analyze a single company basic problem and find the optimal solutions on prices and capacity. Based on the single company model, we address the two-product, two-firm capacity commitment and pricing problem considering across product and across company price competition factors. The existence and uniqueness of equilibrium on price and capacity commitment are proved, and then we extended the results to the multiple product, multiple company case.

关键词： Capacity commitment multiple product pricing product substitution price competition stochastic demand

Preliminary assessment of the solar resource in the United Kingdom

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Clean Energy 2018年第2期2卷 112-125页

作者： Mahmoud Dhimish Violeta Holmes Peter Mather Martin Sibley Laboratory of Photovoltaics School of Computing and EngineeringUniversity of HuddersfieldUnited Kingdom

Solar radiation resources data are the foundation of knowledge for programs of large-scale deployment of solar energy *** article summarizes the analysis of a new weather stations network in the United *** analysis used three years(January 2015-December 2017)of data from 27 weather stations distributed across the *** data comprises global horizontal irradiance(GHI),diffuse horizontal irradiance,direct normal irradiance and the ambient *** design,implementation and data quality assurance are described to document the network extent and *** all observed datasets,we found that Plymouth(located in southwest England)has the dominant GHI and ambient temperature among all other 26 *** least GHI is observed for Aberdeen(located in northeast Scotland)estimated at 77.3 kWh/*** least average ambient temperature is equal to 9.1℃;the data were detected by the weather station located in the capital of Scotland(Edinburgh).Although continued measurements are needed to understand the interannual resource variability,the current study should have significant applications for preliminary technology selection,power plant modeling and resource forecasting.

关键词： solar resources GHI ambient temperature United Kingdom

THE DISTRIBUTION-FREE NEWSVENDOR PROBLEM WITH BALKING AND PENALTIES FOR BALKING AND STOCKOUT

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Journal of Systems Science and Systems Engineering 2014年第2期23卷 153-175页

作者： Hui Yu Jia Zhai school of Economics and business Administration Chongqing University school of business Administration Chongqing University of Technology

This paper investigates the ordering policy for the newsvendor problem with customer balking and penalties for balking and stockout. Our analysis is based on the assumption that only the mean and the variance of the demand distribution are known. In contrast to the existing research, we provide a new tradeoff tool as a replacement of the traditional one to weigh the holding cost and the goodwill cost segment： the balking penalty cost and the stockout penalty cost. Specifically, in addition to the stockout penalty, we also introduce the balking penalty, provide a new proof of the optimality of robust ordering policy to guarantee that the lower bound of expected profit obtained by us is tight, and get an robust optimal order quantity which is an exact solution but not an approximate one as before. Numerical experiments are conducted to illustrate the effect of penalties for balking and stockout.

关键词： Newsvendor problem distribution-free customer balking balking penalty stockout penalty