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Experiments offer incredible value to science, but results must always come with an uncertainty quantification to be meaningful. This requires grappling with sources of uncertainty and how to reduce them. In wind energy, field experiments are sometimes conducted with a control and treatment. In this scenario uncertainty due to bias errors can often be neglected as they impact both control and treatment approximately equally. However, uncertainty due to random errors propagates such that the uncertainty in the difference between the control and treatment is always larger than the random uncertainty in the individual measurements if the sources are uncorrelated. As random uncertainties are usually reduced with additional measurements, there is a need to know the minimum duration of an experiment required to reach acceptable levels of uncertainty. We present a general method to simulate a proposed experiment, calculate uncertainties, and determine both the measurement duration and the experiment duration required to produce statistically significant and converged results. The method is then demonstrated as a case study with a virtual experiment that uses real-world wind resource data and several simulated tip extensions to parameterize results by the expected difference in power. With the method demonstrated herein, experiments can be better planned by accounting for specific details such as controller switching schedules, wind statistics, and postprocess binning procedures such that their impacts on uncertainty can be predicted and the measurement duration needed to achieve statistically significant and converged results can be determined before the experiment. [ABSTRACT FROM AUTHOR]

Copyright of Contaduría y Administración is the property of Facultad de Contaduria y Administracion-Universidad Nacional Autonoma de Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of JFMR - Journal of Fisheries & Marine Research is the property of Brawijaya University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aerodynamic-load calculation in aero-hydro-servo-elastic modeling tools has been recently validated against experiments for low-frequency platform motions but without considering the capability of active wind turbine controls. This work presents a control design framework that allows for including industry-standard wind turbine control functionalities in a model-scale rotor and its application to a 1 V 100 scaled version of the International Energy Agency (IEA) 15MW turbine. Wind tunnel tests with a fixed foundation and steady wind show the scaled turbine reproduces the steady-state rotor speed-blade pitch-thrust-torque characteristics of the IEA 15MW turbine, confirming the controller design method. Tests with a prescribed platform pitch motion are carried out to assess the turbine response and controller modeling in conditions representative of the normal operation of floating wind turbines. The blade element momentum model of OpenFAST is verified against the experiment, showing aerodynamic thrust and torque are predicted with higher accuracy in the belowrated than the above-rated region: in our simulation, the decrease in thrust oscillation amplitude due to blade pitch actuation is underpredicted. This, combined with uncertainty in modeling the blade pitch actuators, complicates the numerical-experimental simulation of the turbine aerodynamic response in above-rated operation. [ABSTRACT FROM AUTHOR]

Controllership in the public sector represents an important tool in government management, contributing to the rational use of resources, in order to provide greater transparency. The general objective of the study is to suggest guidelines for the creation of a controllership unit in the Regional Council of Pharmacy of the State of Ceará (CRF/CE). The research methodology has a qualitative approach and is characterized as an exploratory study, with a single case study, using document analysis, observation and interview techniques. The results indicated that the CRF/CE did not have an internal controllership unit to regulate the control practices in the entity, as well as it appears that its departments carry out their controls independently and isolated from the organization. In the end, it was concluded that the creation of a Controllership unit in the CRF/CE is perfectly feasible, as it has an administrative and physical structure capable of efficiently, effectively and effectively implementing a unit of this type. The study emphasizes the need for qualified professionals, participative management and process stability. The results were well received by the board, aiming to add value and strengthen interdisciplinarity in public management. [ABSTRACT FROM AUTHOR]

This paper compares force and strain feedback for a contact force controller implemented in a constrained flexible manipulator for three-dimensional motion. In the experiments, force inputs of -1, -2 and -3 N were supplied as targets along z-axis direction and the feedback methods compared for their ability in tracking the supplied force. From the results, strain feedback was able to correct for slippage on the contact surface due to increased input force. It was thus concluded that strain feedback is better than force feedback for the constrained flexible manipulator. As a general guideline, it was also found that recordings should be collected at tip of the manipulator instead of the root to reduce noise levels. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid non-linear voltage controller design approach for DC–DC buck converters where the hybridization is done by combining two non-linear techniques: backstepping and sliding mode. In the proposed hybrid framework, the backstepping approach ensures the tracking of all states, while the sliding mode scheme with an enhanced reaching law is utilized for the finite-time convergence of voltage and current in DC– DC buck converters. In this way, the proposed hybrid scheme offers two-degree freedom instead of one-degree in existing nonlinear approaches for controlling DC–DC converters, while guaranteeing the time-time convergence that is not achievable with existing methods in the same application. In this work, the sliding surface is modified to capture changes in the load and supply voltage and the Lyapunov stability theory is used to assess the overall stability of DC–DC buck converters with the proposed controller. Simulation and experimental validations are conducted for evaluating the performance of this hybrid scheme, including a comparative study of an existing sliding mode controller in which the sliding surface is selected as the fast terminal one while avoiding the non-singularity and incorporating the adaptation law. [ABSTRACT FROM AUTHOR]

This paper proposes a robust H∞-LMI-based primary controller using the Linear Parameter Varying (LPV) modeling for an AC Islanded Microgrid (IMG). The proposed controller can regulate the frequency and voltage of the IMG under various scenarios, such as load changes, faults, and reconfigurations. Unlike most previous studies that neglected the nonlinearity and uncertainty of the system, this paper represents the system dynamics as a polytopic LPV model in the novel primary control structure. The proposed method computes a state-feedback control by solving the corresponding Linear Matrix Inequalities (LMIs) based on H∞ performance and stability criteria. The robust primary control is applied to a test IMG in the SIM-POWER environment of MATLAB and evaluated under different scenarios. The simulation results demonstrate the effectiveness and efficiency of the proposed method in maintaining the stability of the frequency and voltage of the IMG. [ABSTRACT FROM AUTHOR]

In this paper, we propose a Virtual Prototype (VP) driven verification methodology for Hardware (HW) peripherals. In particular, we combine two approaches that complement each other and use the VP as a readily available reference model: We use (A) Coverage-Guided Fuzzing (CGF) which enables comprehensive verification at the unit-level of the Register-Transfer Level (RTL) HW peripheral with a Transaction Level Modeling (TLM) reference, and (B) an application-driven co-simulation-based approach that enables verification of the HW peripheral at the system-level. As a case-study, we utilize a RISC-V Platform Level Interrupt Controller (PLIC) as HW peripheral and use an abstract TLM PLIC implementation from the open source RISC-V VP as the reference model. In our experiments we find three behavioral mismatches and discuss the observation of these, as well as non-functional timing behavior mismatches, that were found through the proposed synergistic approach. Furthermore, we provide a discussion and considerations on the RTL/TLM Transactors, as they embody one keystone in cross-level methods. As the different approaches uncover different mismatches in our case-study (e.g., behavioral mismatches and timing mismatches), we conclude a synergy between the methods to aid in verification efforts. [ABSTRACT FROM AUTHOR]

From the last decades different types of network schemes are pitched to enhance the user performance. Software Defined Networks (SDN) is also considered as important factor for different network schemes and its proper administration or management. Due to major deployment in today's networking era SDN are further sub divided in to commercial and opensource controllers. Commercial and open-source controllers are utilized in different type of businesses. According to our knowledge considerable amount of literature is available on these controllers but did not provide or analyse performance of these controllers on different network parameters. This paper evaluates and compares the performance of two well-known SDN open-source controllers POX and RYU with two performance assessments. The first assessment is the implementation of optimal path by using Dijkstra's algorithm from source to destination. Second assessment is the creation of a custom topology in our desired tool (MiniNet emulator). Then, the performance in terms of QoS parameters such as Jitter, throughput, packet loss, and packet delivery ratio are computed by two end hosts in each network. After the assessments, the performance of POX are optimal as compare to the RYU and best suited to be deployed in any scenario. [ABSTRACT FROM AUTHOR]

Copyright of Duzce University Journal of Science & Technology is the property of Duzce University Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Digitization is a megatrend that strongly influences organisations and is reflected in all business processes and operational functions. It is therefore not surprising that controlling is also affected by digitization. This paper first defines and explains the key sub-processes of controlling and describes the traditional role and tasks of controllers that are derived from this. Next, selected technologies such as the internet of things, big data, cloud computing and artificial intelligence are described in detail and their influence on controlling and the role of the controller is analysed. It is shown that digitization is already having a significant impact on controlling and still holds considerable potential for the future. This will also lead inevitably to a continuous refinement of the role and tasks of controllers, whereby they will have to further expand their knowledge and skills in the future. [ABSTRACT FROM AUTHOR]

Providers sometimes create moving arrows, 3D objects, effects, and other items to guide the users of VR spaces. It should be possible to provide better visual guidance and increase its effectiveness by investigating how users feel about how these guiding items move in VR spaces. In this study, with the aim of creating more effective interactions for visual guidance, we provided subjects with the task of visually registering the trajectory of a moving body in a VR space using simple solid shapes. We investigated how the user’s perception of motion was affected by the speed of movement and range of movement of the object and by the distance between the user and the object. We found that the optimal distance for perception of motion in a VR space was 12 meters, and the wider the range of movement, the higher the correct answer rate. It was found that the object’s speed of movement had a small effect on the perception of motion if the speed was within the range in which its motion could be registered. It was also revealed that the combination of the distance between the user and the moving body and the speed at which it moves significantly affects the user’s perception of its motion. A subjective evaluation showed that users felt that ‘speed’ greatly affects their perception of motion. [ABSTRACT FROM AUTHOR]

The object of research is the temperature regime of melting in a cupola. The synthesis of optimal control of such an object is associated with the presence of a problem consisting in the complexity of its mathematical description and the absence of procedures that allow one to obtain optimal control laws. These problems are due to the presence of links with a pure delay, non-additive random drift, and difficulties in controlling the process parameters, in particular, accurately determining the temperature profile along the horizons and the periphery of the working space of the cupola. The proposed conceptual solution for the synthesis of optimal temperature control allows the use of two levels of control: the level controller solves the problem of maintaining the constant height of the idle charge, and the problem of increasing the temperature of cast iron is solved by controlling the air supply to the tuyere box. It is shown that the problem of regulating the upper level of an idle charge can be solved by reducing the model of the regulation process to a typical form, followed by the use of the Pontryagin maximum principle. A procedure for the synthesis of optimal air flow control is proposed, which makes it possible to obtain the temperature regime control law on the basis of experimental industrial studies preceding the synthesis process. This takes into account the time delay between the impact on the object and its reaction, which makes it possible to predict the temperature value one step acharge, equal to the time interval during which the lower surface of the fuel charge reaches the upper surface of the level of the idle charge. A procedure for temperature profile control based on the use of D-optimal plans for selecting sensor installation points is proposed. Due to this, it becomes possible to determine the temperature profile of the cupola according to its horizons and the periphery of the working space of the cupola with maximum accuracy. The proposed synthesis method can be used in iron foundries equipped with cupolas, as it is a tool for studying a real production process, taking into account its specific conditions. This will allow developing or improving control systems for cupola melting, implementing different control modes: manual, automated or automatic. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of Nanjing University of Aeronautics & Astronautics is the property of Editorial Department of Journal of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the Robust Output Feedback controller (ROF) is designed based on the H8 theory and implemented in the liquid level control of the coupled tank system. As many chemical processes have complicated and nonlinear characteristics, this robust methodology is proposed to overcome them. Hence, the vertical coupled tank system is selected as one of the popular case study systems to simulate the large scaled chemical processes to illustrate the effectiveness of the proposed ROF controller. Linear Matrix Inequalities (LMIs) methodology is selected as the main mathematical method of the design procedure. To demonstrate the performance and robustness of the ROF controller, the simulation and experimental results are compared with the Feedforward Proportional Integrator, one of the most common controllers in the industries. Two different liquid-level control scenarios are considered in this comparison and the obtained results show the expected performance of the ROF controller guaranteeing the design objectives. [ABSTRACT FROM AUTHOR]

This work represents a new method for robustness analysis of the model reference adaptive controller (MRAC) in the presence of input saturation. Saturation is one of the nonlinear factors affecting the stability of control systems which must be considered in controller design and stability analysis experiments. Various methods are presented for the stability and robustness analysis of adaptive control systems, and employment of describing function (DF) can be attractive and practical, due to the appropriate effectiveness of DF in estimating limit cycles and also the application of quasi-linearization theory. In this work, the stability analysis and a limit cycle estimation of a saturated system in the frequency domain are performed. The controller parameters are adjusted in a way that the system achieves its stable limit cycle in the presence of the initial conditions for the states. Moreover, the efficiency of the proposed method for second-order systems is reported in the presence of symmetric saturation and uncertainty model in Rohrs’s counterexample as the unmodeled dynamics. The results demonstrate the proposed method provides a proper analysis of system stability during the changes in the control parameters and the saturation amplitude. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of Nanjing University of Aeronautics & Astronautics is the property of Editorial Department of Journal of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the advent of Industry 4.0, industrial facilities and critical infrastructures are transforming into an ecosystem of heterogeneous physical and cyber components, such as programmable logic controllers, increasingly interconnected and therefore exposed to cyber-physical attacks, i.e., security breaches in cyberspace that may adversely affect the physical processes underlying industrial control systems. In this article, we propose a formal approach based on runtime enforcement to ensure specification compliance in networks of controllers, possibly compromised by colluding malware that may locally tamper with actuator commands, sensor readings, and inter-controller communications. Our approach relies on an adhoc sub-class of Ligatti et al.'s edit automata to enforce controllers represented in Hennessy and Regan's Timed Process Language. We define a synthesis algorithm that, given an alphabet P of observable actions and a timed correctness property e, returns a monitor that enforces the property e during the execution of any (potentially corrupted) controller with alphabet P, and complying with the property e. Our monitors do mitigation by correcting and suppressing incorrect actions of corrupted controllers and by generating actions in full autonomy when the controller under scrutiny is not able to do so in a correct manner. Besides classical requirements, such as transparency and soundness, the proposed enforcement enjoys deadlock- and diverge-freedom of monitored controllers, together with scalability when dealing with networks of controllers. Finally, we test the proposed enforcement mechanism on a non-trivial case study, taken from the context of industrialwater treatment systems, in which the controllers are injected with different malware with different malicious goals. [ABSTRACT FROM AUTHOR]

Homomorphic encryption is an effective way to address the privacy and security issues of Networked Control Systems (NCSs). Since the control function needs to be redesigned according to the homomorphism to complete encrypted computing, the practical implementation of a perfectly secure and highly efficient NCS is challenging. Previously proposed NCSs based on homomorphic encryption are still subject to the risk of eavesdropping attacks. In this paper, a combined homomorphic encryption scheme is designed to build a secure environment for NCSs. This scheme comprehensively enhances the security of NCSs by eliminating potential security hazards. The risk of eavesdropping attacks on information in the controller and communication channel is avoided. More specifically, the entire control scheme is encrypted and privacy computing within the controller is performed on this basis. Data protection is provided for all transmission channels, including the transmission of the intermediate result and controller state. In particular, the computational efficiency of the encrypted control system is fast and feasible for real-time control. The performance and stability of the closed-loop system are maintained. [ABSTRACT FROM AUTHOR]

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper investigates the finite-time stabilization problem of fractional-order nonlinear differential systems via an asymmetrically saturated reliable control in the sense of Caputo's fractional derivative. In particular, an asymmetrical saturation control problem is converted to a symmetrical saturation control problem by using a linear matrix inequality framework criterion to achieve the essential results. Specifically, in this paper, we obtain two sets of sufficient conditions under different scenarios of structured uncertainty, namely, norm-bounded parametric uncertainty and linear fractional transformation uncertainty. The uncertainty considered in this paper is a combination of polytopic form and structured form. With the help of control theories of fractional-order system and linear matrix inequality technique, some sufficient criteria to ensure reliable finite-time stability of fractional-order differential systems by using the indirect Lyapunov approach are derived. As a final point, the derived criteria are numerically validated by means of examples based on financial fractional-order differential system and permanent magnet synchronous motor chaotic fractional-order differential system. [ABSTRACT FROM AUTHOR]