Optimal residual generation for fault detection in linear discrete time-varying systems with uncertain observations     

Yueyang Li  Hamid Reza Karimi  Choon Ki Ahn  Yuan Xu  Dong Zhao 《Journal of The Franklin Institute》2018,355(7):3330-3353

This work deals with the problem of optimal residual generation for fault detection (FD) in linear discrete time-varying (LDTV) systems subject to uncertain observations. By introducing a generalized fault detection filter (FDF) with four parameter matrices as the residual generator, a novel FDF design scheme is formulated as two bi-objective optimization problems such that the sensitivity of residual to fault is enhanced and the robustness of residual to unknown input is simultaneously strengthened. A generalized operator based optimization approach is proposed to deduce solutions to the corresponding optimization problems in operator forms, where the related H_∞/H_∞ or $H_{?}/H_{\infty }$ FD performance index is maximized. With the aid of the addressed methods, the connections among the derived solutions are explicitly announced. The parameter matrices of the FDF are analytically derived via solving simple matrix equations recursively. It is revealed that our proposed results establish an operator-based framework of optimal residual generation for some kinds of linear discrete-time systems. Illustrative examples are given to show the applicability and effectiveness of the proposed methods.  相似文献   

A neural network-based detection and mitigation system for unintended acceleration     

Reza Langari 《Journal of The Franklin Institute》2018,355(10):4315-4335

Modern vehicles are equipped with a growing number of electronic devices, which significantly improve the driving experience. However, the complicated architecture of electronic systems also increases the difficulty of fault diagnosis since process models are often unavailable. This paper presents a novel detection and mitigation system for vehicle related anomalies originating in unintended acceleration (UA), which has become one of the most complained-about vehicle problems in recent history. The detection system consists of several neural network-based models, which are created by analyzing historical vehicle data at specific moments such as acceleration peaks and gear shifting. These data-driven models describe the boundary of normal vehicle behavior in the data space. A priori knowledge of complete vehicle structures is not necessary for building them. The detection system combines these models to decide if a UA event has occurred. When a UA event is detected, a mitigation system cuts the engine power and adjusts the braking force accordingly. The whole system was validated in the Simulink/dSPACE environment. UA errors were simulated so that they occurred randomly when human subjects drove virtual cars in a simulated environment. Random noise of sensors were also considered and incorporated to add realism. Various traffic scenarios were included in tests. Test results show that the integrated system is capable of detecting UA in one second with high accuracy and reducing the risk of accidents.  相似文献   

A cognitive TV white space-broadband power line MIMO system for indoor communication networks     

Mohammad Heggo  Xu Zhu  Sumei Sun  Yi Huang 《Journal of The Franklin Institute》2018,355(11):4755-4770

Broadband power line communication (BPLC) is a promising solution to satisfy the growing data rate demands for broadband indoor communication networks. However, the BPLC transmission power spectral density (PSD) is restricted in the very high frequency (VHF) band to avoid harmful interference to the existing wireless services. In this paper, a new hybrid system is proposed utilizing BPLC and cognitive radio over TV white space (TVWS) to enhance the system capacity over BPLC in VHF, forming a VHF TVWS BPLC multiple-input multiple-output (MIMO) system. An iterative precoding algorithm is proposed to satisfy the interference limit at the TV primary user (PU) receiver (Rx) and enhance the ergodic capacity. Moreover, a power allocation algorithm is developed for the MIMO system to achieve the maximum ergodic capacity subject to the average total power constraint and limit of interference to TV PU. Simulation results demonstrate the significant enhancement in the achieved capacity by our proposed system in the VHF band compared to both previous cognitive and hybrid BPLC systems.  相似文献   

Agency,sociomateriality, and configuration work     

Mohammad Hossein Jarrahi  Sarah Beth Nelson 《The Information Society》2018,34(4):244-260

Social informatics research offers insights into the relationship between information technologies and social contexts. However, the material roles of information technologies, and their interplay with the agentic work of social actors, have not been addressed. Drawing on a field study of 37 mobile knowledge workers, we examine the dual material roles (enabling and constraining) played by information technologies in their work practices. We also investigate how these workers exert agency by fashioning multiple information technologies into a functioning digital assemblage. Although information technologies provide consequential affordances that enable mobilization of work across spaces and times, they simultaneously present design-driven, local, organizational, and temporal technological constraints that require mobile knowledge workers to engage in “configuration work” to make information technologies function effectively. Building on a sociomaterial perspective, we further discuss the interplay of information technologies and work practices enacted by mobile knowledge workers, in which both human and technological agency are materialized.  相似文献   

Social media networks and pedagogy at the University of Jordan     

Huda Karajeh  Mahmoud Maqableh  Lama Rajab  Hiba Mohammad  Tahani Khatib  Nabeel Al-Qirim  Ali Tarhini 《Education and Information Technologies》2018,23(5):2073-2090

This study examined impact of a social media networks course on student use of SNSs performance. Moreover, it examined the associations among course design, course materials, learning experiences and a social media networks course. Survey instrument is used to examine the relationships in the proposed model. A total of 380 questionnaires have been collected from students at the University of Jordan who studied the social media networks course. A structural equation modelling approach based on AMOS 20.0 statistical software is used to study the causal relationships and test the hypotheses between the observed and latent constructs in the proposed research model. The analysis results revealed that course materials and learning experiences directly, positively and significantly impacted the social media networks course, which in turn had a significant impact on students’ use social networks sites performance. Course design, however, did not impact the social media networks course. Our findings have important implications as we demonstrated the validity of the joint two different models and provide information about impact of studying social media networks course on students’ academic performance.  相似文献   

Towards skin polarization characterization using polarimetric technique     

Pejhman Ghassemi  Mohammad Hossein Miranbaygi 《Journal of Zhejiang University. Science. B》2009,10(8):602-608

Measurement of optical properties of skin is an expanding and growing field of research. Recent studies have shown that the biological tissue, especially skin, changes the polarization state of the incident light. Using this property will enable the study of abnormalities and diseases that alter not only the light intensity but also its polarization state. In this paper we report an experimental study for measuring changes of polarization state of the light scattered from a phantom similar to a sample model of scattering skin. Using the notation of Stokes vector for the polarized light and Mueller matrix for the sample with its polarization properties, we have shown that some elements of the matrix were particularly sensitive to the changes of the polarization-altering physical properties of the scatterers within the phantom.   相似文献   

Characterization of a-Si:H/SiN multilayer waveguide polarization using an optical pumping application—LED   总被引：1，自引：1，他引：0  

Mohd Saiful Dzulkefly Zan  Isamu Kato  Mohammad Syuhaimi Ab-Rahman  Seri Mastura Mustaza 《浙江大学学报(A卷英文版)》2009,10(10):1421-1427

This paper describes the fabrication of a waveguide and the analysis of its polarization characteristics by applying light-emitting diode （LED） pumping lights to its surface. By using double tubed coaxial line （DTCL） microwave plasma chemical vapor deposition （MPCVD） equipment, an a-Si：H/SiN multilayer waveguide was fabricated whose thickness could be controlled at nanometer order. The main structural material of the waveguide sample consisted of a combination of layers of amorphous silicon hydrogen and silicon nitrate. Once the sample was ready, another major objective of the experiment was to analyze the polarization characteristics of the fabricated waveguide. The idea of the experiment was to analyze how the waveguide reacts when three types of LED （blue, yellow, and red） are radiated onto its surface. The results showed that the fabrication of the a-Si：H/SiN sample is successful. Most effective transmission results, which accord with the polarization characteristics analysis, were obtained.  相似文献   

Speaker adapted dynamic lexicons containing phonetic deviations of words     

Bahram Vazirnezhad  Farshad Almasganj  Seyed Mohammad Ahadi  Ari Chanen 《浙江大学学报(A卷英文版)》2009,10(10):1461-1475

Speaker variability is an important source of speech variations which makes continuous speech recognition a difficult task. Adapting automatic speech recognition （ASR） models to the speaker variations is a well-known strategy to cope with the challenge, Almost all such techniques focus on developing adaptation solutions within the acoustic models of the ASR systems. Although variations of the acoustic features constitute an important portion of the inter-speaker variations, they do not cover variations at the phonetic level. Phonetic variations are known to form an important part of variations which are influenced by both micro-segmental and suprasegmental factors. Inter-speaker phonetic variations are influenced by the structure and anatomy of a speaker＇s articulatory system and also his/her speaking style which is driven by many speaker background characteristics such as accent, gender, age, socioeconomic and educational class. The effect of inter-speaker variations in the feature space may cause explicit phone recognition errors. These errors can be compensated later by having appropriate pronunciation variants for the lexicon entries which consider likely phone misclassifications besides pronunciation. In this paper, we introduce speaker adaptive dynamic pronunciation models, which generate different lexicons for various speaker clusters and different ranges of speech rate. The models are hybrids of speaker adapted contextual rules and dynamic generalized decision trees, which take into account word phonological structures, rate of speech, unigram probabilities and stress to generate pronunciation variants of words. Employing the set of speaker adapted dynamic lexicons in a Farsi （Persian） continuous speech recognition task results in word error rate reductions of as much as 10.1% in a speaker-dependent scenario and 7.4% in a speaker-independent scenario.  相似文献   

Prioritization of intellectual capital indicators in knowledge-based industries: Evidence from pharmaceutical industry     

Gholamhossein Mehralian  Hamid Reza Rasekh  Peyman Akhavan  Ali Rajabzadeh Ghatari 《International Journal of Information Management》2013

During the last decade, intellectual capital (IC) and intangible assets have been widely considered as critical tool to deliver successful business in an intensive-knowledge environment. Accordingly, the main goal of this paper is therefore to develop and prioritize the most important indicators of intellectual capital in knowledge-based industries. Based on an extensive literature review, a valid and reliable questionnaire was designed. In order to data gathering, it was sent out to participants from both academic and university who qualified well in pharmaceutical practice. In order to exact prioritization of indicators, fuzzy TOPSIS technique as a MADM model was used. The fuzzy TOPSIS results revealed participants remark high concerns especially about knowledge and skills of managers and employees regarding to human capital, high concerns particularly about positive climate, ratio of investment in R&D and numbers of R&D projects according to structural capital, while considering the relational capital, more attention was paid to customers and strategic cooperation such as alliances and licensing.  相似文献   

To be or not to be in social media: How brand loyalty is affected by social media?     

Michel Laroche  Mohammad Reza Habibi  Marie-Odile Richard 《International Journal of Information Management》2013

There is an ongoing debate over the activities of brands and companies in social media. Some researchers believe social media provide a unique opportunity for brands to foster their relationships with customers, while others believe the contrary. Taking the perspective of the brand community building plus the brand trust and loyalty literatures, our goal is to show how brand communities based on social media influence elements of the customer centric model (i.e., the relationships among focal customer and brand, product, company, and other customers) and brand loyalty. A survey-based empirical study with 441 respondents was conducted. The results of structural equation modeling show that brand communities established on social media have positive effects on customer/product, customer/brand, customer/company and customer/other customers relationships, which in turn have positive effects on brand trust, and trust has positive effects on brand loyalty. We find that brand trust has a fully mediating role in converting the effects of enhanced relationships in brand community to brand loyalty. The implications for marketing practice and future research are discussed.  相似文献