6,024 research outputs found

    Adaptive non-singular fast terminal sliding mode control and synchronization of a chaotic system via interval type-2 fuzzy inference system with proportionate controller

    Get PDF
    This paper introduces a novel adaptive nonsingular fast terminal sliding mode approach that benefits from an interval type-2 fuzzy logic estimator and a gain for control and synchronization of chaotic systems in the presence of uncertainty. The nonsingular fast terminal sliding mode controller is developed to increase the convergence rate and remove the singularity problem of the system. Using the proposed method, the finite-time convergence has been ensured. To eliminate the chattering phenomenon in the conventional sliding mode controller, the discontinuous sign function is estimated using an interval type-2 fuzzy inference system (FIS) based on the center of sets type reduction followed by defuzzification. By adding the proportionate gain to the interval type-2 FIS, the robustness and speed of the controller system is enhanced. An appropriate Lyapunov function is utilized to ensure the closed-loop stability of the control system. The performance of the controller is evaluated for a nonlinear time-varying second-order magnetic space-craft chaotic system with different initial conditions in the presence of uncertainty. The simulation results show the efficacy of the proposed approach for the tracking control problems. The time and frequency domain analysis of the control signal demonstrates that the chattering phenomenon is successfully diminished

    An empirical investigation of the relationship between integration, dynamic capabilities and performance in supply chains

    Get PDF
    This research aimed to develop an empirical understanding of the relationships between integration, dynamic capabilities and performance in the supply chain domain, based on which, two conceptual frameworks were constructed to advance the field. The core motivation for the research was that, at the stage of writing the thesis, the combined relationship between the three concepts had not yet been examined, although their interrelationships have been studied individually. To achieve this aim, deductive and inductive reasoning logics were utilised to guide the qualitative study, which was undertaken via multiple case studies to investigate lines of enquiry that would address the research questions formulated. This is consistent with the author’s philosophical adoption of the ontology of relativism and the epistemology of constructionism, which was considered appropriate to address the research questions. Empirical data and evidence were collected, and various triangulation techniques were employed to ensure their credibility. Some key features of grounded theory coding techniques were drawn upon for data coding and analysis, generating two levels of findings. These revealed that whilst integration and dynamic capabilities were crucial in improving performance, the performance also informed the former. This reflects a cyclical and iterative approach rather than one purely based on linearity. Adopting a holistic approach towards the relationship was key in producing complementary strategies that can deliver sustainable supply chain performance. The research makes theoretical, methodological and practical contributions to the field of supply chain management. The theoretical contribution includes the development of two emerging conceptual frameworks at the micro and macro levels. The former provides greater specificity, as it allows meta-analytic evaluation of the three concepts and their dimensions, providing a detailed insight into their correlations. The latter gives a holistic view of their relationships and how they are connected, reflecting a middle-range theory that bridges theory and practice. The methodological contribution lies in presenting models that address gaps associated with the inconsistent use of terminologies in philosophical assumptions, and lack of rigor in deploying case study research methods. In terms of its practical contribution, this research offers insights that practitioners could adopt to enhance their performance. They can do so without necessarily having to forgo certain desired outcomes using targeted integrative strategies and drawing on their dynamic capabilities

    Key technologies for safe and autonomous drones

    Get PDF
    Drones/UAVs are able to perform air operations that are very difficult to be performed by manned aircrafts. In addition, drones' usage brings significant economic savings and environmental benefits, while reducing risks to human life. In this paper, we present key technologies that enable development of drone systems. The technologies are identified based on the usages of drones (driven by COMP4DRONES project use cases). These technologies are grouped into four categories: U-space capabilities, system functions, payloads, and tools. Also, we present the contributions of the COMP4DRONES project to improve existing technologies. These contributions aim to ease drones’ customization, and enable their safe operation.This project has received funding from the ECSEL Joint Undertaking (JU) under grant agreement No 826610. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Spain, Austria, Belgium, Czech Republic, France, Italy, Latvia, Netherlands. The total project budget is 28,590,748.75 EUR (excluding ESIF partners), while the requested grant is 7,983,731.61 EUR to ECSEL JU, and 8,874,523.84 EUR of National and ESIF Funding. The project has been started on 1st October 2019

    Intelligent computing : the latest advances, challenges and future

    Get PDF
    Computing is a critical driving force in the development of human civilization. In recent years, we have witnessed the emergence of intelligent computing, a new computing paradigm that is reshaping traditional computing and promoting digital revolution in the era of big data, artificial intelligence and internet-of-things with new computing theories, architectures, methods, systems, and applications. Intelligent computing has greatly broadened the scope of computing, extending it from traditional computing on data to increasingly diverse computing paradigms such as perceptual intelligence, cognitive intelligence, autonomous intelligence, and human computer fusion intelligence. Intelligence and computing have undergone paths of different evolution and development for a long time but have become increasingly intertwined in recent years: intelligent computing is not only intelligence-oriented but also intelligence-driven. Such cross-fertilization has prompted the emergence and rapid advancement of intelligent computing

    Modelling, Monitoring, Control and Optimization for Complex Industrial Processes

    Get PDF
    This reprint includes 22 research papers and an editorial, collected from the Special Issue "Modelling, Monitoring, Control and Optimization for Complex Industrial Processes", highlighting recent research advances and emerging research directions in complex industrial processes. This reprint aims to promote the research field and benefit the readers from both academic communities and industrial sectors

    Affinity-Based Reinforcement Learning : A New Paradigm for Agent Interpretability

    Get PDF
    The steady increase in complexity of reinforcement learning (RL) algorithms is accompanied by a corresponding increase in opacity that obfuscates insights into their devised strategies. Methods in explainable artificial intelligence seek to mitigate this opacity by either creating transparent algorithms or extracting explanations post hoc. A third category exists that allows the developer to affect what agents learn: constrained RL has been used in safety-critical applications and prohibits agents from visiting certain states; preference-based RL agents have been used in robotics applications and learn state-action preferences instead of traditional reward functions. We propose a new affinity-based RL paradigm in which agents learn strategies that are partially decoupled from reward functions. Unlike entropy regularisation, we regularise the objective function with a distinct action distribution that represents a desired behaviour; we encourage the agent to act according to a prior while learning to maximise rewards. The result is an inherently interpretable agent that solves problems with an intrinsic affinity for certain actions. We demonstrate the utility of our method in a financial application: we learn continuous time-variant compositions of prototypical policies, each interpretable by its action affinities, that are globally interpretable according to customers’ financial personalities. Our method combines advantages from both constrained RL and preferencebased RL: it retains the reward function but generalises the policy to match a defined behaviour, thus avoiding problems such as reward shaping and hacking. Unlike Boolean task composition, our method is a fuzzy superposition of different prototypical strategies to arrive at a more complex, yet interpretable, strategy.publishedVersio

    Sport team leadership coaching and captaincy in elite level rugby union football

    Get PDF
    A wide range of literature exists on coaching but it is concerned predominantly with the high school and college levels, is based upon athlete or coach perceptions, or is confined to observations of training or competition. As leaders of sports teams, coaches and captains have rarely been studied at the highest level of national or international sports competition. In the present study, the team leadership roles of the coach and captain in elite rugby union football in New Zealand were examined using participant observation and other qualitative research methods. Elite was defined as New Zealand rugby’s highest internal level of competition: (a) the national provincial championships and (b) international test matches of the national team, the All Blacks. The study explored the roles of the elite rugby coach and captain in vivo in a wide variety of team situations. It was felt that this could provide first-hand information on particular team leader behaviours, on what a coach and captain actually do, and how they are perceived by those around them. The main objective, however, was to use grounded theory techniques to create a model of elite rugby team leadership that might guide developmental programmes on such leadership. The research phases undertaken were those of participant observation with a Provincial Team for five matches, a survey of provincial teams’ coaches and captains on their leadership associated with actual matches, three years’ participant observation with the All Blacks (including observation in eight test match weeks), multiple perspectives on elite team leadership from past rugby test players in New Zealand and overseas, and interviews with national team leaders in sports other than rugby. Participant observation, interviews, questionnaires and document analysis generated data from the research settings. These data were considered in terms of symbolic interactionism and subjected to a grounded theory process. This led to a set of elite rugby team leadership categories and properties which, in turn, generated a comprehensive set of theoretical propositions. The propositions became the basis for a model of elite rugby team leadership. This model was then considered as the basis for a programme to develop elite rugby team leaders. Significant aspects of the research findings which have not featured in previous research literature included the coach’s vision, team culture, centrality of the game plan, match week build-up, the importance of the captain’s playing example, the coach's ability to utilise teaching precepts, the coach’s personal qualities, and the need to develop and evaluate team leaders. The model, and the developmental programme principles emanating from it, are seen as relevant for developing elite level leaders in team sports other than rugby

    Trade Union Effectiveness in the UK Hospitality Sector: A Case Study Approach

    Get PDF
    This study investigates how union representation, management attitude, union membership, collective bargaining, and technological revolution affect trade union effectiveness in the UK hospitality industry. It specifically explores how internal organisational factors and trade union factors impact the effectiveness of trade unions in the UK hospitality sector, as well as how improvement in such effectiveness can benefit employers and employees in this sector. An analysis of seven case studies of hotels in the UK was conducted, which included a total of 71 interviews with employees and hotel managers, seven meeting observations, and an analysis of documents from each hotel. All these data were analysed thematically using NVivo 12. Key findings revealed that two hotels were strongly unionised while the rest were weakly unionised. The unionised hotels had strong union representation, bargaining power and an adequate and growing union membership. The weakly unionised hotels had weak bargaining power and declining membership. Workers from weakly unionised hotels began to turn to management efficiency to seek resolutions for their concerns. Conversely, workers from strongly unionised hotels sought union representation to resolve their issues with the management. The study contributes a proposed conceptual framework of trade union effectiveness applied to the seven case organisations
    • 

    corecore