Research on robust adaptive sliding film fault-tolerant control under nonlinear distortion of signal transmission in amorphous flat air-to-ground wireless ad-hoc network system

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhifang Wang ◽  
Jianguo Yu ◽  
Shangjing Lin
Keyword(s):  
Nonlinear Distortion ◽  
Ad Hoc ◽  
Fault Tolerant ◽  
Signal Transmission ◽  
Network System ◽  
Long Distance ◽  
Content Type ◽  
Wireless Signal ◽  
Robust Adaptive ◽  
Self Organizing

Purpose To solve the above problems and ensure the stability of the ad hoc network node topology in the process of wireless signal transmission, this paper aims to design a robust adaptive sliding film fault-tolerant controller under the nonlinear distortion of signal transmission in an amorphous flat air-to-ground wireless ad hoc network system. Design/methodology/approach This paper designs a robust adaptive sliding film fault-tolerant controller under the nonlinear distortion of signal transmission in an amorphous flat air-to-ground wireless ad hoc network system. Findings The simulation results show that the amorphous flat wireless self-organizing network system has good nonlinear distortion fault-tolerant correction ability under the feedback control of the designed controller, and the system has the asymptotically stable convergence ability; the test results show: the node topology of the self-organizing network structural stability is significantly improved, which provides a foundation for the subsequent realization of long-distance transmission of ad hoc network nodes. Research limitations/implications Because of the chosen research approach, the research results may lack generalizability. Therefore, researchers are encouraged to test the proposed propositions further. Originality/value The controller can extract the fault information caused by nonlinear distortion in the wireless signal transmission process, and at the same time, its feedback matrix K can gradually converge the generated wireless signal error to zero, to realize the stable transmission of the wireless signal.

Distributed robust H∞ adaptive fault-tolerant control of amorphous and flat air-to-ground wireless self-organizing network system

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhifang Wang ◽  
Jianguo Yu ◽  
Shangjing Lin ◽  
Junguo Dong ◽  
Zheng Yu
Keyword(s):  
Flight Control ◽  
Control Algorithm ◽  
Ad Hoc ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Integrated System ◽  
External Disturbances ◽  
Content Type ◽  
Actuator Failures ◽  
Wireless Signal

Purpose The paper takes the air-ground integrated wireless ad hoc network-integrated system as the research object, this paper aims to propose a distributed robust H∞ adaptive fault-tolerant control algorithm suitable for the system to distribute to solve the problem of control and communication failure at the same time. Design/methodology/approach In the paper, the authors propose a distributed robust H∞ adaptive fault-tolerant control algorithm suitable for the air-ground integrated wireless ad hoc network-integrated system. Findings The results show that the integrated system has good robustness and fault tolerance performance indicators for flight control and wireless signal transmission when confronted with external disturbances, internal actuator failures and wireless network associated failures and the flight control curve of the quadrotor unmanned aerial vehicle (UAV) is generally smooth and stable, even if it encounters external disturbances and actuator failures, its fault tolerance performance is very good. Then in the range of 400–800 m wireless communication distance, the success rate of wireless signal loop transmission is stable at 80%–100% and the performance is at least relatively improved by 158.823%. Originality/value This paper takes the air-ground integrated wireless ad hoc network-integrated system as the research object, based on the robust fault-tolerant control algorithm, the authors propose a distributed robust H∞ adaptive fault-tolerant control algorithm suitable for the system and through the Riccati equation and linear matrix inequation method, the designed distributed robust H∞ adaptive fault-tolerant controller further optimizes the fault suppression factor γ, so as to break through the limitation of only one Lyapunov matrix for different fault modes to distribute to solve the problem of control and communication failure at the same time.

Vibration sensor for the health monitoring of the large rotating machinery: review and outlook

Sensor Review ◽  
2018 ◽  
Vol 38 (1) ◽  
pp. 44-64 ◽  
Author(s):  
Shaoyi Xu ◽  
Fangfang Xing ◽  
Ruilin Wang ◽  
Wei Li ◽  
Yuqiao Wang ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Health Monitoring ◽  
Electromagnetic Interference ◽  
Signal Transmission ◽  
Rotating Machinery ◽  
Vibration Sensor ◽  
Future Research ◽  
Long Distance ◽  
Content Type ◽  
Advantages And Disadvantages

Purpose At present, one of the key equipment in pillar industries is a large rotating machinery. Conducting regular health monitoring is important for ensuring safe operation of the large rotating machinery. Because vibrations sensors play an important role in the workings of the rotating machinery, measuring its vibration signal is an important task in health monitoring. This paper aims to present these. Design/methodology/approach In this work, the contact vibration sensor and the non-contact vibration sensor have been discussed. These sensors consist of two types: the electric vibration sensor and the optical fiber vibration sensor. Their applications in the large rotating machinery for the purpose of health monitoring are summarized, and their advantages and disadvantages are also presented. Findings Compared with the electric vibration sensor, the optical fiber vibration sensor of large rotating machinery has unique advantages in health monitoring, such as provision of immunity against electromagnetic interference, requirement of less insulation and provision of long-distance signal transmission. Originality/value Both contact vibration sensor and non-contact vibration sensor have been discussed. Among them, the electric vibration sensor and the optical fiber vibration sensor are compared. Future research direction of the vibration sensors is presented.

A status quo analysis of disaster risk reduction policy and legislation in Cameroon

foresight ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 362-376 ◽  
Author(s):  
R.E.A. Ashu ◽  
Dewald Van Niekerk
Keyword(s):  
Risk Reduction ◽  
Disaster Response ◽  
Disaster Risk Reduction ◽  
Qualitative Method ◽  
Ad Hoc ◽  
Disaster Risk ◽  
Status Quo ◽  
Content Type ◽  
Development Institutions ◽  
The Status

Purpose The purpose of this paper is to analyze the status quo of disaster risk reduction (DRR) policy and legislation in Cameroon. Design/methodology/approach Using a qualitative method, this paper examines historical data from sectoral administrative reports, plans, declarations, commitments and speeches, texts and peer-reviewed journals on disaster and risk management in Cameroon for the period 1967-2017. Empirical data from ten selected government sectors were used to analyze the status quo, together with quantitative data collected by using four instruments (i.e. HFA Priority 1 & 4, USAID Toolkit, GOAL Resilience Score and the Checklist on Law and DRR). Findings Findings show that Cameroon largely still practices disaster response through the Department of Civil Protection. Transparency and accountability are the sine qua non of the state, but the lack thereof causes improper implementation of DRR within development institutions. DRR is seen as an ad hoc activity, with the result that there is not effective institutional capacity for implementation. The need to develop a new national DRR framework is evident. Originality/value Analyzing the status quo of DRR in Cameroon could assist with the review and reevaluation of a new DRR framework within the Cameroonian territory.

The deputy principal instructional leadership role and professional learning

2017 ◽  
Vol 55 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Ann Leaf ◽  
George Odhiambo
Keyword(s):  
Instructional Leadership ◽  
Professional Learning ◽  
Ad Hoc ◽  
Team Building ◽  
Leadership Role ◽  
Instructional Leaders ◽  
Structured Interviews ◽  
Content Type ◽  
Practical Implications

Purpose The purpose of this paper is to report on a study examining the perceptions of secondary principals, deputies and teachers, of deputy principal (DP) instructional leadership (IL), as well as deputies’ professional learning (PL) needs. Framed within an interpretivist approach, the specific objectives of this study were: to explore the extent to which DPs are perceived as leaders of learning, to examine the actual responsibilities of these DPs and to explore the PL that support DP roles. Design/methodology/approach The researchers used multiple perspective case studies which included semi-structured interviews and key school document analysis. A thematic content analysis facilitated qualitative descriptions and insights from the perspectives of the principals, DPs and teachers of four high-performing secondary schools in Sydney, Australia. Findings The data revealed that deputies performed a huge range of tasks; all the principals were distributing leadership to their deputies to build leadership capacity and supported their PL in a variety of ways. Across three of the case study schools, most deputies were frequently performing as instructional leaders, improving their school’s performance through distributing leadership, team building and goal setting. Deputy PL was largely dependent on principal mentoring and self-initiated but was often ad hoc. Findings add more validity to the importance of principals building the educational leadership of their deputies. Research limitations/implications This study relied upon responses from four case study schools. Further insight into the key issues discussed may require a longitudinal data that describe perceptions from a substantial number of schools in Australia over time. However, studying only four schools allowed for an in-depth investigation. Practical implications The findings from this study have practical implications for system leaders with responsibilities of framing the deputies’ role as emergent educational leaders rather than as administrators and the need for coherent, integrated, consequential and systematic approaches to DP professional development. Further research is required on the effect of deputy IL on school performance. Originality/value There is a dearth of research-based evidence exploring the range of responsibilities of deputies and perceptions of staff about deputies’ IL role and their PL needs. This is the first published New South Wales, Australian DP study and adds to the growing evidence around perceptions of DPs as instructional leaders by providing an Australian perspective on the phenomenon. The paper raises important concerns about the complexity of the DP’s role on the one hand, and on the other hand, the PL that is perceived to be most appropriate for dealing with this complexity.

Ethnicity as inclusion and exclusion

2016 ◽  
Vol 29 (8) ◽  
pp. 1262-1269 ◽  
Author(s):  
Rachel F. Baskerville ◽  
Kerry Jacobs ◽  
Vassili Joannides de Lautour ◽  
Jeff Sissons
Keyword(s):  
Ad Hoc ◽  
Cultural Perspective ◽  
Special Issue ◽  
Culture Theory ◽  
Grid And Group ◽  
Group Culture ◽  
Content Type ◽  
Accounting Research ◽  
Mary Douglas ◽  
The Relationship

Purpose Accounting research has struggled with how ethnicity is to be understood in relation to concepts such as nation and nationality and how ethnicity may impact on accounting and auditing practices, behaviours, education and professional values. These themes are explored and developed in the papers presented in this special issue. In particular, the purpose of this paper is to explore the contrasting theoretical and methodological approaches reflected by the papers in the issue. Design/methodology/approach This is a reflective and analytical paper which explores how notions of ethnicity are conceived and operationalised in accounting research. The authors identified two distinctive analytic ordering processes evident within this AAAJ Special issue: Mary Douglas’ scheme of Grid and Group and the Pierre Bourdieu’s conceptual tools of field, capital and habitus. Findings The “Grid and Group” Culture Theory with Bourdieu’s theoretical tools evident in the papers provide powerful tools to explore the relationship between ethnicity and accounting both conceptually and empirically, suggesting that ethnicity can be deployed to reveal and challenge institutionalised racism. This paper highlights the potential to integrate elements of the “Grid and Group” Culture Theory and Bourdieu’s theoretical tools. The issue of ethnicity and the relationship between ethnicity and accounting should be more fruitfully explored in future. Research limitations/implications The authors acknowledge the challenges and limitations of discussing the issue of ethnicity from any particular cultural perspective and recognise the implicit dominance of White Anglo centric perspectives within accounting research. Originality/value The papers presented in the special issue illustrate that the issue of ethnicity is complex and difficult to operationalise. This paper highlights the potential to move beyond the ad hoc application of theoretical and methodological concepts to operationalise coherent concepts which challenge and extend the authors’ understanding of accounting as a social and contextual practice. But to achieve this it is necessary to more clearly integrate theory, methodology, method and critique.

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