Academic literature on the topic 'Extended state observers'

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Journal articles on the topic "Extended state observers"

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Ali, Jarinah Mohd, and M. A. Hussain. "Artificial Intelligence Based State Observer in Polymerization Process." ASEAN Journal of Chemical Engineering 13, no. 2 (2014): 50. http://dx.doi.org/10.22146/ajche.49731.

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Observers or state estimators are devices used to estimate immeasurable key parameters that are due to noise, disturbances and mismatch. It is important to identify those variables prior to construct a control system and avoid fault or process disruption. In certain chemical processes, such observer usage produced unsatisfactory results therefore hybrid approached is the appropriate solution. Hybrid observers are combination of two or more conventional observers mainly to enhance the estimator’s performance and overcoming their limitations. In advanced cases, Artificial Intelligence algorithm is applied. This paper develops two hybrid observers namely sliding mode and extended Luenberger observers with fuzzy logic for approximating the monomer concentration in a polymerization reactor. It was found that the sliding mode observer- fuzzy combination is better based on noise handling with less oscillation.
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Martínez-García, Edgar Alonso, Joaquín Rivero-Juárez, Luz Abril Torres-Méndez, and Jorge Enrique Rodas-Osollo. "Divergent trinocular vision observers design for extended Kalman filter robot state estimation." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 233, no. 5 (2018): 524–47. http://dx.doi.org/10.1177/0959651818800908.

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Here, we report the design of two deterministic observers that exploit the capabilities of a home-made divergent trinocular visual sensor to sense depth data. The three-dimensional key points that the observers can measure are triangulated for visual odometry and estimated by an extended Kalman filter. This work deals with a four-wheel-drive mobile robot with four passive suspensions. The direct and inverse kinematic solutions are deduced and used for the updating and prediction models of the extended Kalman filter as feedback for the robot’s position controller. The state-estimation visual odometry results were compared with the robot’s dead-reckoning kinematics, and both are combined as a recursive position controller. One observer model design is based on the analytical geometric multi-view approach. The other observer model has fundamentals on multi-view lateral optical flow, which was reformulated as nonspatial–temporal and is modeled by an exponential function. This work presents the analytical deductions of the models and formulations. Experimental validation deals with five main aspects: multi-view correction, a geometric observer for range measurement, an optical flow observer for range measurement, dead-reckoning and visual odometry. Furthermore, comparison of positioning includes a four-wheel odometer, deterministic visual observers and the observer–extended Kalman filter, compared with a vision-based global reference localization system.
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Humaidi, Amjad J. "Experimental Design and Verification of Extended State Observers for Magnetic Levitation System Based on PSO." Open Electrical & Electronic Engineering Journal 12, no. 1 (2018): 110–20. http://dx.doi.org/10.2174/1874129001812010110.

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Introduction: This work presents analysis, design and implementation of two schemes of Extended State Observer (ESO) to estimate the position, velocity and unmeasurable states for magnetic levitation systems, Linear ESO (LESO) and Nonlinear ESO (NESO). The multiplicity of design parameters for both LESO and NESO made it difficult to find appropriate setting of these parameters such that to reach satisfactory performance of observation process. Methods: Particle Swarm Optimization (PSO) technique is used to improve performance of observation process by finding optimal tuned parameters of observer design parameter subjected to specified performance index. Theoretical results of both observers are firstly implemented in the environment of MATLAB/SIMULINK. Then, experimental state estimation of observers is set up based on feedback instrument (33-942S) to verify the simulated results. Results and Conclusion: Root Mean Square (RMS) of estimation error has been used as an indicator to assess the performance of observers. The simulated and practical results showed that LESO could give better estimation performance than NESO.
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Gu, Nan, Dan Wang, Zhouhua Peng, Jun Wang, and Qing-Long Han. "Disturbance observers and extended state observers for marine vehicles: A survey." Control Engineering Practice 123 (June 2022): 105158. http://dx.doi.org/10.1016/j.conengprac.2022.105158.

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Liu, Jiahao, Zhiqiang Zeng, Shangyao Shi, and Pengyun Chen. "Internal Model Principle-Based Extended State Observer for the Uncertain Systems with Nonconstant Disturbances." Actuators 13, no. 1 (2024): 29. http://dx.doi.org/10.3390/act13010029.

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Existing traditional expansion state observers exhibit good tracking performance for constant and low-frequency disturbances. However, their ability to track non-constant disturbances such as ramp and high-frequency harmonics is inadequate. This paper proposes an extended state observer design method based on the internal model principle. This method achieves precise tracking of non-constant disturbances in the system, effectively addressing the issue of disturbance estimation errors in conventional expansion state observers. When applied to control systems, this approach significantly mitigates or suppresses system vibrations caused by non-constant disturbances, thereby enhancing control accuracy. Furthermore, it demonstrates the stability of the controlled system and the active disturbance rejection controller parameters over a wide range of variations. Simulation results indicate that the ADRC controller based on the proposed observer in this paper offers notable advantages, including high tracking accuracy, strong disturbance rejection capability, and good stability, leading to commendable control performance.
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Zárate-Castrejón, José Luis, Pablo A. López-Pérez, Milagros López-López, et al. "Estimation of Sporulated Cell Concentration of Bacillus thuringiensis in a Batch Biochemical Reactor via Simple State Observers." Mathematics 12, no. 24 (2024): 3996. https://doi.org/10.3390/math12243996.

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This paper presents a contrast of two different observation strategies viz a nonlinear observer and a classical extended Luenberger observer applied to a bioreactor system for Bacillus thuringiensis production. The performance of the two observers was evaluated under different conditions, both with and without state perturbations. Firstly, equal initial conditions were considered without the presence of white noise in the measurement of dissolved oxygen concentration in the culture medium. The performance was then analyzed by perturbing the maximum cell growth rate with equal and different initial conditions, and, finally, the performance of the observer with the presence of white noise was evaluated. The proposed observer performed better than the extended Luenberger observer against initial conditions different from the model. The results of this study are of great interest, as they provide insight into the estimation of the state of the dynamics for the B. thuringiensis bioreactor in a batch mode. In addition, these results provide valuable information for future research in the design of observers for B. thuringiensis bioprocessing.
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Parada, Ricardo P., A. Tadeo Espinoza, Alejandro E. Dzul, and Francisco G. Salas. "Performance analysis of nonlinear observers applied to the fixed-wing unmanned aerial vehicles flight under decoupled-reduced model." International Journal of Micro Air Vehicles 9, no. 2 (2017): 111–23. http://dx.doi.org/10.1177/1756829317702673.

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In this paper, we present the design and implementation of two nonlinear observers: nonlinear extended state observer and sliding mode observer for estimating the pitch, yaw and roll angles and angular rates of a fixed-wing unmanned aerial vehicles system under a decoupled-reduced model in real flight experiments. A backstepping control law is designed for control in a decentralized way for altitude, yaw and roll of the airplane. This scheme allows us to test experimentally the feasibility of using the online estimated data from the observers in flight control, which is useful for increasing the robustness of the control and the safety of flight. Furthermore, a comparative analysis of the performance of both nonlinear observers is conducted.
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Siket, Máté, György Eigner, Dániel András Drexler, Imre Rudas, and Levente Kovács. "State and Parameter Estimation of a Mathematical Carcinoma Model under Chemotherapeutic Treatment." Applied Sciences 10, no. 24 (2020): 9046. http://dx.doi.org/10.3390/app10249046.

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One challenging aspect of therapy optimization and application of control algorithms in the field of tumor growth modeling is the limited number of measurable physiological signals—state variables—and the knowledge of model parameters. A possible solution to provide such information is the application of observer or state estimator. One of the most widely applied estimators for nonlinear problems is the extended Kalman filter (EKF). In this study, a moving horizon estimation (MHE)-based observer is developed and compared to an optimized EKF. The observers utilize a third-order tumor growth model. The performance of the observers is tested on measurements gathered from a laboratory mice trial using chemotherapeutic drug. The proposed MHE is designed to be suitable for closed-loop applications and yields simultaneous state and parameter estimation.
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Proietti, Massimiliano, Alexander Pickston, Francesco Graffitti, et al. "Experimental test of local observer independence." Science Advances 5, no. 9 (2019): eaaw9832. http://dx.doi.org/10.1126/sciadv.aaw9832.

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The scientific method relies on facts, established through repeated measurements and agreed upon universally, independently of who observed them. In quantum mechanics the objectivity of observations is not so clear, most markedly exposed in Wigner’s eponymous thought experiment where two observers can experience seemingly different realities. The question whether the observers’ narratives can be reconciled has only recently been made accessible to empirical investigation, through recent no-go theorems that construct an extended Wigner’s friend scenario with four observers. In a state-of-the-art six-photon experiment, we realize this extended Wigner’s friend scenario, experimentally violating the associated Bell-type inequality by five standard deviations. If one holds fast to the assumptions of locality and free choice, this result implies that quantum theory should be interpreted in an observer-dependent way.
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Asiri, Sharefa, Chadia Zayane-Aissa, and Taous-Meriem Laleg-Kirati. "An Adaptive Observer-Based Algorithm for Solving Inverse Source Problem for the Wave Equation." Mathematical Problems in Engineering 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/796539.

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Observers are well known in control theory. Originally designed to estimate the hidden states of dynamical systems given some measurements, the observers scope has been recently extended to the estimation of some unknowns, for systems governed by partial differential equations. In this paper, observers are used to solve inverse source problem for a one-dimensional wave equation. An adaptive observer is designed to estimate the state and source components for a fully discretized system. The effectiveness of the algorithm is emphasized in noise-free and noisy cases and an insight on the impact of measurements’ size and location is provided.
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Dissertations / Theses on the topic "Extended state observers"

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Mohammed, Ali. "PASSIVITY-BASED TRACKING CONTROL OF A ROBOT MANIPULATOR USING AN EXTENDED STATE OBSERVER." Cleveland State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=csu1590253786792864.

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Lim, Hong Sun. "Design and Control of A Ropeless Elevator with Linear Switched Reluctance Motor Drive Actuation Systems." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/26541.

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Linear switched reluctance motor (LSRM) drives are investigated and proved as an alternative actuator for vertical linear transportation applications such as a linear elevator. A one-tenth scaled prototype elevator focused on a home elevator with LSRMs is designed and extensive experimental correlation is presented for the first time. The proposed LSRM has twin stators and a set of translator poles without back-iron. The translators are placed between the two stators. The design procedures and features of the LSRM and the prototype elevator are described. The designed LSRM is validated through a finite element analysis (FEA) and experimental measurements. Furthermore, a control strategy for the prototype elevator is introduced consisting of four control loops, viz., current, force, velocity, and position feedback control loops. For force control, a novel force distribution function (FDF) is proposed and compared with conventional FDFs. A trapezoidal velocity profile is introduced to control vertical travel position smoothly during the elevator's ascent, descent, and halt operations. Conventional proportional plus integral (PI) controller is used for the current and velocity control loops and their designs are described. The proposed control strategy is dynamically simulated and experimentally correlated. Analytical and experimental results of this research prove that LSRMs are one of the strong candidates for ropeless linear elevator applications. However, the proposed FDF is assuming that the feedback current signals are ideal currents indicating actual phase currents without any measurement disturbances mainly arising from sensor noise, DC-link voltage ripple, measurement offset, and variations in the plant model. Meanwhile, real control systems in industry have measurement disturbance problems. Phase current corrupted by measurement disturbances increases torque or force ripple, acoustic noise and EMI. Therefore, this dissertation also presents a novel current control method to suppress measurement disturbances without extra hardware. The controller is based on an extended state observer (ESO) and a nonlinear P controller (NLP). The proposed method does not require an accurate mathematical model of system and can be implemented on a low-cost DSP controller. The proposed ESO is exploited to estimate the measurement disturbances on measured phase currents, and the proposed NLP compensates for the measurement disturbances estimated by the ESO. The performance of the proposed current control is validated through extensive dynamic simulations and experiments. Moreover, this rejection of measurement disturbances results in a reduction of force ripple and acoustic noise. Due to superior and robust current control performance, it is believed that the proposed method can be successfully applied into other motor drive systems to suppress measurement disturbances with the same promising results without extra hardware.<br>Ph. D.
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Zagorski, Scott B. "Modeling, Control and State Estimation of a Roll Simulator." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1349900540.

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Mohorcic, John Francis. "Pressure-based Impedance Control of a Pneumatic Actuator." Cleveland State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=csu1591188440286793.

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Ye, Maosheng. "Road Surface Condition Detection and Identification and Vehicle Anti-Skid Control." Cleveland State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1227197539.

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Ranka, Trupti. "Disturbance Rejection Control for The Green Bank Telescope." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459556332.

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Tamagnini, Filippo. "EKF based State Estimation in a CFI Copolymerization Reactor including Polymer Quality Information." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/20235/.

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State estimation is an integral part of modern control techniques, as it allows to characterize the state information of complex plants based on a limited number of measurements and the knowledge of the process model. The benefit is twofold: on one hand it has the potential to rationalize the number of measurements required to monitor the plant, thus reducing costs, on the other hand it enables to extract information about variables that have an effect on the system but would otherwise be inaccessible to direct measurement. The scope of this thesis is to design a state estimator for a tubular copolymerization reactor, with the aim to provide the full state information of the plant and to characterize the quality of the product. Due to the fact that, with the existing set of measurements, only a small number of state variables can be observed, a new differential pressure sensor is installed in the plant to provide the missing information, and a model for the pressure measurement is developed. Following, the state estimation problem is approached rigorously and a comprehensive method for analyzing, tuning and implementing the state estimator is assembled from scientific literature, using a variety of tools from graph theory, linear observability theory and matrix algebra. Data reduction and visualization techniques are also employed to make sense of high dimensional information. The proposed method is then tested in simulations to assess the effect of the tuning parameters and measured set on the estimator performance during initialization and in case of estimation with plant-model mismatch. Finally, the state estimator is tested with plant data.
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Gaudenzi, de faria Marcelo. "Robust control for manipulation inside a scanning electron microscope." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2068/document.

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Cette thèse étudie le problème de nano-positionnement à l'intérieur d'un microscope électronique à balayage (MEB). Pour obtenir des informations de position avec rapidité et précision, une installation dédiée composée d’un vibromètre placé à l'intérieur du MEB a été mise en œuvre. Cette approche diffère de méthodes basées sur le traitement d'images, car elle permet de saisir des données en temps réel sur le comportement dynamique des structures étudiées. Dans une première étude, les perturbations mécaniques agissant à l'intérieur de la chambre à vide du microscope ont été caractérisées et leurs sources ont été identifiées. Cela a démontré comment les vibrations mécaniques externes et les bruits acoustiques peuvent influer largement sur les composants à l'intérieur du MEB par couplage mécanique, limitant ainsi la précision des manipulateurs. Dans un deuxième temps, une micro-pince du commerce a été étudiée. Une différence entre ses comportements dans l'air et dans le vide a été mise en évidence, ce qui a permis d'obtenir deux modèles dynamiques pour cet organe terminal, un pour chaque environnement. Deux lois de commande ont été proposées (commande H-infini et commande basée sur un observateur d'état étendu), afin d'obtenir en temps réel un positionnement précis dans le vide, et d'atténuer les effets des perturbations mécaniques externes. Les résultats ont été validés en simulation et expérimentalement<br>This work studies the nano-positioning problem inside the scanning electron microscope (SEM). To acquire fast and accurate positional information, a dedicated setup was implemented consisting of a vibrometer placed inside the SEM. This approach differs from methods based on image processing, as it allows to capture real-time data on the dynamic behavior of structures. In a first study, the mechanical disturbances acting inside the microscope’s vacuum chamber were characterized and its sources were identified. This demonstrated how external mechanical vibrations and acoustic noises can largely influence the components inside the SEM through mechanical coupling, limiting the effective positioning precision of manipulators. Next, a commercial micro-gripper was studied, both in air and in vacuum, and the differences between its response were highlighted. This allowed to obtain two dynamic models for this end-effector, one for each environment. Two control laws were proposed (H-infinity control and Extended State Observer based control) for the system, to obtain a real-time, precise positioning in the vacuum environment and to attenuate the effects of the external mechanical disturbances. Results were demonstrated through simulation and experimental validation
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Chen, Yi-Ting, and 陳逸庭. "Analysis of convergence and parameter selection of single-parameter extended state observer." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/zga3dh.

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碩士<br>國立交通大學<br>電控工程研究所<br>101<br>Parameters selection of an observer is well known to have great influence on its convergence speed and estimation accuracy. In this thesis, we will employ the self stable region concept, introduced by Dr. Han, to analyze the convergence and accuracy of a single-parameter extended state observer (ESO). A condition that guarantees the error state converging to a linear region of the ESO is proposed. Moreover, when given a desired estimation error, we also present a guideline of parameter selection to realize the demand of estimation error whenever the derivative of the unknown parameter is known. Simulation results have clearly demonstrated the effectiveness of the design.
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Yen-ChunChen and 陳彥君. "Study on Contour Accuracy Improvement Based on Friction Model and Adaptive PI-type Sliding Mode Extended State Observer." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/s4w2qc.

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碩士<br>國立成功大學<br>電機工程學系<br>107<br>The nonlinear phenomena and external disturbances often found in the servomechanisms such as X-Y tables and CNC machines may deteriorate the tracking accuracy. Among them, friction is the most common nonlinear external disturbance in the X-Y tables and CNC machines. Hence, one of the main research topics of this thesis is to explore and construct various friction models so as to design friction compensation schemes to overcome the influence of friction on the system. This thesis compares the effectiveness of several friction models in suppressing the adverse effects caused by friction. Both the LuGre and GMS friction models are constructed and their effectiveness on low speed compensation and tracking accuracy improvement are compared. In addition to friction, CNC machines often encounter phenomenon such as backlash and modelling inaccuracy. In order to accurately estimate position, velocity and total disturbance of the system, the extended state observer (ESO) is another research topic in this thesis. Combining the model-based complementary sliding mode controller with the adaptive PI sliding mode extended state observer (APISMESO) proposed in this thesis can not only accurately estimate the system states such as position and velocity, but also compensate the estimated total disturbance into the system so as to achieve the goal of high contour following accuracy. To verify the feasibility of the proposed approach, this thesis not only conducts MATLAB simulation, but also uses the X-Y table to perform contour following experiments. Experimental results show that the proposed adaptive PISMESO is superior to other ESO architectures in estimating accuracy and feedback compensation.
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Books on the topic "Extended state observers"

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Japan. Whaling, international observer scheme: Agreement between the United States of America and Japan, extending the agreement of May 2, 1975, as extended, effected by exchange of notes signed at Tokyo March 18, 1986. Dept. of State, 1995.

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Osanloo, Arzoo. Forgiveness Work. Princeton University Press, 2020. http://dx.doi.org/10.23943/princeton/9780691172040.001.0001.

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Iran's criminal courts are notorious for meting out severe sentences—according to Amnesty International, the country has the world's highest rate of capital punishment per capita. Less known to outside observers, however, is the Iranian criminal code's recognition of forgiveness, where victims of violent crimes, or the families of murder victims, can request the state to forgo punishing the criminal. This book shows that in the Iranian justice system, forbearance is as much a right of victims as retribution. Drawing on extended interviews and first-hand observations of more than eighty murder trials, the book explores why some families of victims forgive perpetrators and how a wide array of individuals contribute to the fraught business of negotiating reconciliation. Based on Qur'anic principles, Iran's criminal codes encourage mercy and compel judicial officials to help parties reach a settlement. As no formal regulations exist to guide those involved, an informal cottage industry has grown around forgiveness advocacy. Interested parties—including attorneys, judges, social workers, the families of victims and perpetrators, and even performing artists—intervene in cases, drawing from such sources as scripture, ritual, and art to stir feelings of forgiveness. These actors forge new and sometimes conflicting strategies to secure forbearance, and some aim to reform social attitudes and laws on capital punishment. The book examines how an Islamic victim-centered approach to justice sheds light on the conditions of mercy.
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Abby Cohen, Smutny, Polášek Petr, and Farrell Chad. Part IV Guide to Key Substantive Issues, 23 The MFN Clause and Its Evolving Boundaries. Oxford University Press, 2018. http://dx.doi.org/10.1093/law/9780198758082.003.0023.

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This chapter discusses most-favoured-nation (MFN) clauses from early references in trade agreements to contemporary references in investor-state arbitrations. MFN clauses originated in early international trade practice and have continued to be incorporated in modern trade and investment treaties, both bilateral and multilateral. Their intended purpose is to lessen discrimination and encourage the growth of trade and foreign investment by ensuring that certain defined benefits accorded to one set of States (or their nationals, investments, goods, etc.) are extended to other States (or their nationals, investments, goods, etc.). In the investment treaty context, some commentators have observed that the right to a favourable dispute settlement mechanism is the primary concern of foreign investors, and investors often invoke MFN clauses to secure procedural rights that might otherwise be unavailable to them.
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Vaez-Zadeh, Sadegh. Rotor Position and Speed Estimation. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198742968.003.0006.

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The ultimate importance of rotor position and speed information in permanent magnet synchronous (PMS) machines control, and the industry interest to the rotor and speed sensorless systems as a cost-saving and practical alternative to the motor control with mechanical sensors are emphasized. Major position and speed estimation schemes are then presented in detail. These are the: back electromotive force (EMF)-based method; flux linkage method; hypothesis rotor position method; saliency-based method, including high frequency signal injection and inverter switching harmonics schemes; and finally, the observer-based method, including state observer and extended Kalman filter-based schemes. Each scheme was discussed by presenting the corresponding fundamental principles, followed by the appropriate motor model, estimation procedure, and the implementation. Demanding criteria such as accuracy, robustness, swiftness, and capability of working over the entire range of motor operation are discussed with each method.
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Ossome, Lyn. Gender, Ethnicity, and Violence in Kenya’s Transitions to Democracy. Lexington Books, 2018. https://doi.org/10.5040/9781666992854.

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Critiquing the valorization of democracy as a means of containing violence and stabilizing political contestation, this book draws links between the democratization process and sexual/gendered violence observed against women during electioneering periods in Kenya. The book shows the contradictory relationship between democracy and gendered violence as being largely influenced in the first instance by the capitalist interests vested in the colonial state and its imperative to exploit laboring women; secondly, in the nature of the postcolonial state and politics largely captured by ethnic, bourgeois class interests; and third, influenced by neoliberal political ideology that has remained largely disarticulated from women's structural positions in Kenyan society. It argues that colonial capitalist interests established certain patterns of gender exploitation that extended into the postcolonial period such that the indigenous bourgeoisie took the form of an ethnicized elite. Ethnicity shaped politics and neoliberal political ideology further blocked women’s integration into politics in substantive ways. It concludes that it is not so much the norms and values of liberal democracy that assist in understanding women’s exclusion, but rather the structural dynamics that have shaped women’s experiences of democratic politics. In this way, gender violence in the context of democratization and electoral violence with its gendered manifestation can be fully understood as deeply embedded in the history of the structural dynamics of colonialism, capitalism, and patriarchalism in Kenya.
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Beebe-Dimmer, Jennifer L., Fawn D. Vigneau, and David Schottenfeld. Small Intestine Cancer. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190238667.003.0035.

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The small intestine extends 6–7 meters from the gastric pylorus to its insertion into the large intestine. Its mucosal surface contains 90% of the absorptive surface area of the digestive tract. Remarkably, in 2015, only about 3% of digestive system cancers and less than 1% of digestive cancer deaths in the United States were observed in the small intestine. In contrast, approximately 50% of cancers in the digestive tract were diagnosed in the large intestine, which measures just 1.5 meters in length. Cancers of the small intestine are among the most heterogeneous of gastrointestinal neoplasms, encompassing pathologic subtypes of neuroendocrine carcinoid, adenocarcinoma, lymphoma, and gastrointestinal stromal tumors. Adenocarcinoma accounted for ~25% to–35% of cancers in the small intestine, in contrast to over 90% of cancers in the large intestine. Genetic syndromes, such as familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC), predispose to adenocarcinoma in the small intestine.
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Book chapters on the topic "Extended state observers"

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Shi, Dawei, Yuan Huang, Junzheng Wang, and Ling Shi. "Performance Assessment of Discrete-Time Extended State Observers." In Event-Triggered Active Disturbance Rejection Control. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0293-1_2.

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Dahal, Pragyan, Stefano Arrigoni, Mario Bijelic, and Francesco Braghin. "Vehicle State Estimation Through Dynamics Modeled Factor Graph." In Lecture Notes in Mechanical Engineering. Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-70392-8_119.

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AbstractEgo Vehicle state estimation is integral to every autonomous driving software stack. Thereby, the estimation of the state and its components as for example the side slip angle, is a crucial component to track the vehicle maneuvers. In the absence of a direct sensor measuring side slip angle, most of the existing literature either use observers like Kalman Filters or non-modular factor graphs by modeling lateral dynamics. However, the modularity of such graphs, to integrate multiple asynchronous sensors that provide disentangled measurements, like LiDAR, GNSS, and IMU is still overlooked in the literature. In this work, we propose a novel factor graph-based architecture that builds upon the vehicle dynamics at its core to enable the fusion of multiple sensors asynchronously and enables to perform robust and accurate state estimation.We validate the proposed algorithm against two baselines, a model-based Extended Kalman Filter and a factor graph-based state estimator that uses the IMU pre-integration factor as a reference factor. The algorithms are validated in a custom dataset collected using an in-house vehicle.
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Shi, Dawei, Yuan Huang, Junzheng Wang, and Ling Shi. "Event-Triggered Extended State Observer." In Event-Triggered Active Disturbance Rejection Control. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0293-1_3.

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Xiao, Bing, Zhaoyue Chen, Jingwen Xu, and Lu Cao. "Extended-State Observer-Based Attitude Control." In Advanced Attitude Control of Satellite. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-2847-3_9.

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Wei, Wei, Ping Li, and Min Zuo. "Extended State Observer-Based Sliding Mode Control for Epilepsy." In Lecture Notes in Electrical Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-8450-3_83.

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Xu, Zhao, Yuehui Ji, and Junjie Liu. "Extended State Observer-Backstepping Control for Grid-Tied PV System." In Lecture Notes in Electrical Engineering. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1439-5_102.

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Hu, Qinglei, Bo Li, Bing Xiao, and Youmin Zhang. "Extended State Observer Based Optimal Attitude Robust Control of Spacecraft." In Control Allocation for Spacecraft Under Actuator Faults. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0439-3_6.

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Pu, Cuiping, Jie Ren, and Gang Fang. "Sliding Mode Control of AGV Based on Extended State Observer." In Modern Industrial IoT, Big Data and Supply Chain. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-6141-6_11.

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Yu, Xinhong, Dongliang Ke, Libin Xu, Wei Chen, Nanzhen Chen, and Fengxiang Wang. "Linear Extended State Observer Based Model Predictive Control for Non-isolated Two-Stage Inverter." In Lecture Notes in Electrical Engineering. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-0553-9_18.

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Wu, Dan. "Control Strategy of Unmanned Aerial Vehicle Based on Extended State Observer." In Advances in Intelligent Systems and Computing. Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-15235-2_133.

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Conference papers on the topic "Extended state observers"

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Jiao, Shijian, Lu Liu, Yongqi Yu, Anqing Wang, Dan Wang, and Zhouhua Peng. "State and Disturbance Estimation of Autonomous Surface Vehicles based on Nonlinear Cascade Extended State Observers." In 2024 14th International Conference on Information Science and Technology (ICIST). IEEE, 2024. https://doi.org/10.1109/icist63249.2024.10805285.

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Qu, Yue, Hui Li, Feifei Bai, Junwei Lu, and Fuwen Yang. "Robust Decoupling Control Based on Linear Extended State Observers for Grid-Forming Inverter." In 2024 IEEE 34th Australasian Universities Power Engineering Conference (AUPEC). IEEE, 2024. https://doi.org/10.1109/aupec62273.2024.10807610.

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Li, Bowen, Xiaokang Zhang, and Fei Wang. "An Improved Active Flux Observer Based on Linear Extended State Observer." In 2024 IEEE Transportation Electrification Conference and Expo, Asia-Pacific (ITEC Asia-Pacific). IEEE, 2024. http://dx.doi.org/10.1109/itecasia-pacific63159.2024.10738554.

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Li, Junchi, Mingyi Wang, Minghong Liu, Chengming Zhang, and Liyi Li. "Iterative Learning Controller Based on Linear Extended State Observer for Six-Degree-of-Freedom Micro-Motion Stage." In 2024 27th International Conference on Electrical Machines and Systems (ICEMS). IEEE, 2024. https://doi.org/10.23919/icems60997.2024.10921102.

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Huang, Yuan, Junzheng Wang, and Dawei Shi. "On convergence of extended state observers for discrete-time nonlinear systems." In 2015 34th Chinese Control Conference (CCC). IEEE, 2015. http://dx.doi.org/10.1109/chicc.2015.7259694.

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Cortez, Ricardo, and Ruben Garrido. "Stable Tuning of Extended State Observers using PSO and Penalty Functions." In 2021 IEEE International Conference on Mechatronics and Automation (ICMA). IEEE, 2021. http://dx.doi.org/10.1109/icma52036.2021.9512611.

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Bai, Wenyan, Chen Sen, Yi Huang, Wenchao Xue, and Ping Liu. "On Performance Analysis of General Observers for Uncertain Systems." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67095.

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This paper aims to rigorously study the observer for general uncertain systems. The proposed observer is shown to be the general form of extended state observer (ESO), disturbance observer (DO), generalized extended state observer (GESO) and extended high gain observer (EHGO). The properties of this general observer is discussed by analyzing the estimation error. The paper illustrates that the output of the proposed general observers may not performs as the estimation the real state and uncertainty. We prove that this observer gives the estimations for the group of states and uncertainties whose exact form is given in the paper. Finally, numerical simulations for a typical example validate the theoretical analysis.
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Liu, Lu, Haoliang Wang, Dan Wang, and Zhouhua Peng. "Prediction-Based Event-triggered Extended State Observers Design for Unmanned Surface Vehicles." In 2021 6th International Conference on Automation, Control and Robotics Engineering (CACRE). IEEE, 2021. http://dx.doi.org/10.1109/cacre52464.2021.9501332.

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Vasu, Jonathan, S. Sengupta, A. K. Deb, and S. Mukhopadhyay. "Development of extended MVEM based fault residue generators using UKF state observers." In 2011 Annual IEEE India Conference (INDICON). IEEE, 2011. http://dx.doi.org/10.1109/indcon.2011.6139371.

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Shi, Fengming, and Ron Patton. "Active fault tolerant control of LPV descriptor systems based on extended state observers." In 2014 American Control Conference - ACC 2014. IEEE, 2014. http://dx.doi.org/10.1109/acc.2014.6858837.

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Reports on the topic "Extended state observers"

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Baader, Franz, and Marcel Lippmann. Runtime Verification Using a Temporal Description Logic Revisited. Technische Universität Dresden, 2014. http://dx.doi.org/10.25368/2022.203.

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Formulae of linear temporal logic (LTL) can be used to specify (wanted or unwanted) properties of a dynamical system. In model checking, the system’s behaviour is described by a transition system, and one needs to check whether all possible traces of this transition system satisfy the formula. In runtime verification, one observes the actual system behaviour, which at any point in time yields a finite prefix of a trace. The task is then to check whether all continuations of this prefix to a trace satisfy (violate) the formula. More precisely, one wants to construct a monitor, i.e., a finite automaton that receives the finite prefix as input and then gives the right answer based on the state currently reached. In this paper, we extend the known approaches to LTL runtime verification in two directions. First, instead of propositional LTL we use the more expressive temporal logic ALC-LTL, which can use axioms of the Description Logic (DL) ALC instead of propositional variables to describe properties of single states of the system. Second, instead of assuming that the observed system behaviour provides us with complete information about the states of the system, we assume that states are described in an incomplete way by ALC-knowledge bases. We show that also in this setting monitors can effectively be constructed. The (double-exponential) size of the constructed monitors is in fact optimal, and not higher than in the propositional case. As an auxiliary result, we show how to construct Büchi automata for ALC-LTL-formulae, which yields alternative proofs for the known upper bounds of deciding satisfiability in ALC-LTL.
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Gust, Kurt, Ashley Kimble, J. Mylroie, et al. Bioconcentration, maternal transfer, and toxicokinetics of PFOS in a multi-generational zebrafish exposure. Engineer Research and Development Center (U.S.), 2025. https://doi.org/10.21079/11681/49812.

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To enable risk characterization of perfluorooctane sulfonic acid in extended chronic and multi-generational exposures, we assessed PFOS bioconcentration in zebrafish exposed continuously to environmentally-relevant PFOS concentrations through 180 days postfertilization in parental and first filial generation fish. Exposures included five replicate tanks per treatment where whole-body PFOS concentrations were measured. Perfluorooctane sulfonic acid accumulation reached an apparent steady state at ≤ 14 dpf where whole-body wet-weight concentrations remained constant through 180 dpf in the P and F1 generations. The median bioconcentration factor of 934 L/kg was observed for all PFOS exposures with a range from 255 to 2,136 L/kg which varied with PFOS exposure concentration and sex of adult fish. Maternal transfer of PFOS was observed from P females to F1 eggs where maternal whole-body and egg PFOS burdens were equivalent, suggesting PFOS transfer to eggs was not a depuration pathway. Finally, a toxicokinetic model was developed that reliably reproduced PFOS whole-body burdens across all exposure durations spanning the P and F1 generations, providing a tool for PFOS bioaccumulation predictions relevant for risk assessment of acute, chronic, and multi-generational exposures.
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Bercovier, Herve, and Paul Frelier. Pathogenic Streptococcus in Tilapia: Rapid Diagnosis, Epidemiology and Pathophysiology. United States Department of Agriculture, 1994. http://dx.doi.org/10.32747/1994.7568776.bard.

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Within the project "Pathogenic Streptococcus in Tilapia", gram positive cocci pathogens of fish in Israel and in the United States were characterized. We showed that Streptococcus shiloi, the name for an agent causing septicemic infection in fish, is a junior synonym of Streptococcus iniae and that Enterococcus seriolicida is a junior synonym of Lactococcus garvieae, a causative agent of septicemia and meningo-encephalitis in fish. Molecular epidemiology studies on these two pathogens, based on 16S rDNA sequences and ribotyping showed that although each country had specific clones, S. iniae originated probably from the U.S. and L. garvieae from Japan. PCR assays were developed for both pathogens and applied to clinical samples. S. agalactiael S. difficile was also recognized for the first time in the U.S. in tilapia. Our histopathological studies explained the noted paradox (abundant in vitro growth often accompanied by scant to small numbers of organisms within the meninges in histologic sections of brain) in diagnostic of fish streptococcus. The greatest concentration of cocci were consistently observed within macrophages infiltrating the extrameningeal fibroadipose tissue surrounding the brain within the calvarium. These results also suggests that the primary route of meningeal infection may be extension from the extrameningeal connective tissue rather than meningeal vascular emigration of cocci-containing macrophages. Our work has resulted in a cognizance of streptococcus as fish pathogen which goes beyond the pathology observed in tilapia and is already extended to many aquaculture fish species in Israel and in the United States. Finally, our data suggest that vaccines (bivalent or trivalent) could be developed to prevent most of the damages caused by streptococcus in aquaculture.
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Zheng. L52044 Effects of Operating Practice on Crack Dormancy and Growth. Pipeline Research Council International, Inc. (PRCI), 2005. http://dx.doi.org/10.55274/r0011334.

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This report describes the output of two phases of the research contract on �Effects of Operating Practice on SCC Crack Growth�, GRI-05/8668, submitted to PRCI in August 2002 (Phase I) and in July 2003 (Phase II). The objective of the first phase of the work was to identify, through literature survey, a correlation model that relates the crack growth rate in low-pH or in high-pH environments to the deformation rate of the line pipe steel. The objective of the second phase of the project was to experimentally validate the correlation model(s) identified in Phase I. The ultimate goal of this work is to define the critical loading condit ions necessary for SCC so that operating practices can be assessed for the purpose of eventual avoidance of SCC. It is also hoped that such a deformation-rate-based model can provide insight for understanding the transition between �active� and �inactive� (or dormant) states of the cracking that is often observed in laboratory SCC tests. Understanding the causes for dormancy of stress corrosion cracks and the mechanism(s) of crack reactivation has significant practical implications. Service life is extended if conditions of dormancy can be maintained and conditions of growth or reactivation can be avoided.
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Gattoni and Olsen. PR-179-10211-R01 Advanced Control Techniques and Sensors for Gas Engines with NSCR. Pipeline Research Council International, Inc. (PRCI), 2012. http://dx.doi.org/10.55274/r0010987.

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High exhaust emissions reduction efficiencies from a spark ignited (SI) internal combustion engine utilizing an NSCR catalyst system requires complex fuel control strategies. The allowable equivalence ratio operating range is very narrow where NSCR systems achieve high exhaust emissions reduction efficiencies of multiple species. Current fuel control technologies utilizing lambda sensor feedback are reported to be unable to sustain these demands for extended operation periods and when transients are introduced. Lambda sensor accuracy is the critical issue with current fuel controllers. The goal of this project was to develop a minimization control algorithm utilizing a Nitrogen Oxide (NOx) sensor installed downstream of the NSCR catalyst system for feedback air/fuel ratio control. When the engine is operated lean, NOx is produced and the NOx sensor responds accordingly. When the engine is operated rich, the NSCR catalyst system produces Ammonia. The NOx sensor has a cross sensitivity to Ammonia and responds as though it has been exposed to NOx. This behavior provides an opportunity for a unique control strategy that allows lambda sensor calibration to be ignored. Testing was performed on a 100kW rated Cummins-Onan generator set that was reconfigured to operate utilizing an electronic gas carburetor (EGC2) with lambda sensor feedback and high reduction efficiency NSCR catalyst system. The control algorithm was programmed utilizing a Labview interface that communicated with the electronic gas carburetor where the fuel trim adjustment was physically made. Improvement under steady state operation was observed. The system was also evaluated during load and fuel composition transients.
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Weller, Joel I., Ignacy Misztal, and Micha Ron. Optimization of methodology for genomic selection of moderate and large dairy cattle populations. United States Department of Agriculture, 2015. http://dx.doi.org/10.32747/2015.7594404.bard.

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The main objectives of this research was to detect the specific polymorphisms responsible for observed quantitative trait loci and develop optimal strategies for genomic evaluations and selection for moderate (Israel) and large (US) dairy cattle populations. A joint evaluation using all phenotypic, pedigree, and genomic data is the optimal strategy. The specific objectives were: 1) to apply strategies for determination of the causative polymorphisms based on the “a posteriori granddaughter design” (APGD), 2) to develop methods to derive unbiased estimates of gene effects derived from SNP chips analyses, 3) to derive optimal single-stage methods to estimate breeding values of animals based on marker, phenotypic and pedigree data, 4) to extend these methods to multi-trait genetic evaluations and 5) to evaluate the results of long-term genomic selection, as compared to traditional selection. Nearly all of these objectives were met. The major achievements were: The APGD and the modified granddaughter designs were applied to the US Holstein population, and regions harboring segregating quantitative trait loci (QTL) were identified for all economic traits of interest. The APGD was able to find segregating QTL for all the economic traits analyzed, and confidence intervals for QTL location ranged from ~5 to 35 million base pairs. Genomic estimated breeding values (GEBV) for milk production traits in the Israeli Holstein population were computed by the single-step method and compared to results for the two-step method. The single-step method was extended to derive GEBV for multi-parity evaluation. Long-term analysis of genomic selection demonstrated that inclusion of pedigree data from previous generations may result in less accurate GEBV. Major conclusions are: Predictions using single-step genomic best linear unbiased prediction (GBLUP) were the least biased, and that method appears to be the best tool for genomic evaluation of a small population, as it automatically accounts for parental index and allows for inclusion of female genomic information without additional steps. None of the methods applied to the Israeli Holstein population were able to derive GEBV for young bulls that were significantly better than parent averages. Thus we confirm previous studies that the main limiting factor for the accuracy of GEBV is the number of bulls with genotypes and progeny tests. Although 36 of the grandsires included in the APGD were genotyped for the BovineHDBeadChip, which includes 777,000 SNPs, we were not able to determine the causative polymorphism for any of the detected QTL. The number of valid unique markers on the BovineHDBeadChip is not sufficient for a reasonable probability to find the causative polymorphisms. Complete resequencing of the genome of approximately 50 bulls will be required, but this could not be accomplished within the framework of the current project due to funding constraints. Inclusion of pedigree data from older generations in the derivation of GEBV may result is less accurate evaluations.
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Brosh, Arieh, Gordon Carstens, Kristen Johnson, et al. Enhancing Sustainability of Cattle Production Systems through Discovery of Biomarkers for Feed Efficiency. United States Department of Agriculture, 2011. http://dx.doi.org/10.32747/2011.7592644.bard.

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Feed inputs represent the largest variable cost of producing meat and milk from ruminant animals. Thus, strategies that improve the efficiency of feed utilization are needed to improve the global competitiveness of Israeli and U.S. cattle industries, and mitigate their environmental impact through reductions in nutrient excretions and greenhouse gas emissions. Implementation of innovative technologies that will enhance genetic merit for feed efficiency is arguably one of the most cost-effective strategies to meet future demands for animal-protein foods in an environmentally sustainable manner. While considerable genetic variation in feed efficiency exist within cattle populations, the expense of measuring individual-animal feed intake has precluded implementation of selection programs that target this trait. Residual feed intake (RFI) is a trait that quantifies between-animal variation in feed intake beyond that expected to meet energy requirements for maintenance and production, with efficient animals being those that eat less than expected for a given size and level of production. There remains a critical need to understand the biological drivers for genetic variation in RFI to facilitate development of effective selection programs in the future. Therefore, the aim of this project was to determine the biological basis for phenotypic variation in RFI of growing and lactating cattle, and discover metabolic biomarkers of RFI for early and more cost-effective selection of cattle for feed efficiency. Objectives were to: (1) Characterize the phenotypic relationships between RFI and production traits (growth or lactation), (2) Quantify inter-animal variation in residual HP, (3) Determine if divergent RFIphenotypes differ in HP, residual HP, recovered energy and digestibility, and (4) Determine if divergent RFI phenotypes differ in physical activity, feeding behavior traits, serum hormones and metabolites and hepatic mitochondrial traits. The major research findings from this project to date include: In lactating dairy cattle, substantial phenotypic variation in RFI was demonstrated as cows classified as having low RMEI consumed 17% less MEI than high-RMEI cows despite having similar body size and lactation productivity. Further, between-animal variation in RMEI was found to moderately associated with differences in RHP demonstrating that maintenance energy requirements contribute to observed differences in RFI. Quantifying energetic efficiency of dairy cows using RHP revealed that substantial changes occur as week of lactation advances—thus it will be critical to measure RMEI at a standardized stage of lactation. Finally, to determine RMEI in lactating dairy cows, individual DMI and production data should be collected for a minimum of 6 wk. We demonstrated that a favorably association exists between RFI in growing heifers and efficiency of forage utilization in pregnant cows. Therefore, results indicate that female progeny from parents selected for low RFI during postweaning development will also be efficient as mature females, which has positive implications for both dairy and beef cattle industries. Results from the beef cattle studies further extend our knowledge regarding the biological drivers of phenotypic variation in RFI of growing animals, and demonstrate that significant differences in feeding behavioral patterns, digestibility and heart rate exist between animals with divergent RFI. Feeding behavior traits may be an effective biomarker trait for RFI in beef and dairy cattle. There are differences in mitochondrial acceptor control and respiratory control ratios between calves with divergent RFI suggesting that variation in mitochondrial metabolism may be visible at the genome level. Multiple genes associated with mitochondrial energy processes are altered by RFI phenotype and some of these genes are associated with mitochondrial energy expenditure and major cellular pathways involved in regulation of immune responses and energy metabolism.
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Hammad, Ali, and Mohamed Moustafa. Seismic Behavior of Special Concentric Braced Frames under Short- and Long-Duration Ground Motions. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, 2019. http://dx.doi.org/10.55461/zont9308.

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Over the past decade, several long-duration subduction earthquakes took place in different locations around the world, e.g., Chile in 2010, Japan in 2011, China in 2008, and Indonesia in 2004. Recent research has revealed that long-duration, large-magnitude earthquakes may occur along the Cascadia subduction zone of the Pacific Northwest Coast of the U.S. The duration of an earthquake often affects the response of structures. Current seismic design specifications mostly use response spectra to identify the hazard and do not consider duration effects. Thus, a comprehensive understanding of the effect of the duration of the ground motion on structural performance and its design implications is an important issue. The goal of this study was to investigate how the duration of an earthquake affects the structural response of special concentric braced frames (SCBFs). A comprehensive experimental program and detailed analytical investigations were conducted to understand and quantify the effect of duration on collapse capacity of SCBFs, with the goal of improving seismic design provisions by incorporating these effects. The experimental program included large-scale shake table tests, and the analytical program consisted of pre-test and post-test phases. The pre-test analysis phase performed a sensitivity analysis that used OpenSees models preliminarily calibrated against previous experimental results for different configuration of SCBFs. A tornado-diagram framework was used to rank the influence of the different modeling parameters, e.g., low-cycle fatigue, on the seismic response of SCBFs under short- and long-duration ground motions. Based on the results obtained from the experimental program, these models were revisited for further calibration and validation in the post-test analysis. The experimental program included three large-scale shake-table tests of identical single-story single-bay SCBF with a chevron-brace configuration tested under different ground motions. Two specimens were tested under a set of spectrally-matched short and long-duration ground motions. The third specimen was tested under another long-duration ground motion. All tests started with a 100% scale of the selected ground motions; testing continued with an ever-increasing ground-motion scale until failure occurred, e.g., until both braces ruptured. The shake table tests showed that the duration of the earthquake may lead to premature seismic failure or lower capacities, supporting the initiative to consider duration effects as part of the seismic design provisions. Identical frames failed at different displacements demands because of the damage accumulation associated with the earthquake duration, with about 40% reduction in the displacement capacity of the two specimens tested under long-duration earthquakes versus the short-duration one. Post-test analysis focused first on calibrating an OpenSees model to capture the experimental behavior of the test specimens. The calibration started by matching the initial stiffness and overall global response. Next, the low-cycle fatigue parameters were fine-tuned to properly capture the experimental local behavior, i.e., brace buckling and rupture. The post-test analysis showed that the input for the low-cycle fatigue models currently available in the literature does not reflect the observed experimental results. New values for the fatigue parameters are suggested herein based on the results of the three shake-table tests. The calibrated model was then used to conduct incremental dynamic analysis (IDA) using 44 pairs of spectrally-matched short- and long-duration ground motions. To compare the effect of the duration of ground motion, this analysis aimed at incorporating ground-motion variability for more generalized observations and developing collapse fragility curves using different intensity measures (IMs). The difference in the median fragility was found to be 45% in the drift capacity at failure and about 10% in the spectral acceleration (Sa). Using regression analysis, the obtained drift capacity from analysis was found to be reduced by about 8% on average for every additional 10 sec in the duration of the ground motion. The last stage of this study extended the calibrated model to SCBF archetype buildings to study the effect of the duration of ground motion on full-sized structures. Two buildings were studied: a three-story and nine-story build that resembled the original SAC buildings but were modified with SCBFs as lateral support system instead of moment resisting frames. Two planer frames were adopted from the two buildings and used for the analysis. The same 44 spectrally-matched pairs previously used in post-test analysis were used to conduct nonlinear time history analysis and study the effect of duration. All the ground motions were scaled to two hazard levels for the deterministic time history analysis: 10% exceedance in 50 years and 2% exceedance in 50 years. All analysis results were interpreted in a comparative way to isolate the effect of duration, which was the main variable in the ground-motion pairs. In general, the results showed that the analyzed SCBFs experienced higher drift values under the long-duration suite of ground motions, and, in turn, a larger percentage of fractured braces under long-duration cases. The archetype SCBFs analysis provided similar conclusions on duration effects as the experimental and numerical results on the single-story single-bay frame.
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Jalkanen, Jukka-Pekka, Erik Fridell, Jaakko Kukkonen, et al. Environmental impacts of exhaust gas cleaning systems in the Baltic Sea, North Sea, and the Mediterranean Sea area. Finnish Meteorological Institute, 2024. http://dx.doi.org/10.35614/isbn.9789523361898.

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Description: Shipping is responsible for a range of different pressures affecting air quality, climate, and the marine environment. Most social and economic analyses of shipping have focused on air pollution assessment and how shipping may impact climate change and human health. This risks that policies may be biased towards air pollution and climate change, whilst impacts on the marine environment are not as well known. One example is the sulfur regulation introduced in January 2020, which requires shipowners to use a compliant fuel with a sulfur content of 0.5% (0.1% in SECA regions) or use alternative compliance options (Exhaust Gas Cleaning Systems, EGCS) that are effective in reducing sulfur oxide (SOx) emissions to the atmosphere. The EGCS cleaning process results in large volumes of discharged water that includes a wide range of contaminants. Although regulations target SOx removal, other pollutants such as polycyclic aromatic hydrocarbons (PAHs), metals and combustion particles are removed from the exhaust to the wash water and subsequently discharged to the marine environment. Based on dilution series of the Whole Effluent Testing (WET), the impact of the EGCS effluent on marine invertebrate species and on phytoplankton was found to vary between taxonomic groups, and between different stages of the invertebrate life cycle. Invertebrates were more affected than phytoplankton, and the most sensitive endpoint detected in the present project was the fertilisation of sea urchin eggs, which were negatively affected at a sample dilution of 1 : 1,000,000. Dilutions of 1: 100,000 were harmful to early development of several of the tested species, including mussels, polychaetes, and crustaceans. The observed effects at these low concentrations of EGCS effluent were reduced egg production, and deformations and abnormal development of the larvae of the species. The ecotoxicological data produced in the EMERGE project were used to derive Predicted No Effect Concentration values. Corresponding modelling studies revealed that the EGCS effluent can be considered as a single entity for 2-10 days from the time of discharge, depending on the environmental conditions like sea currents, winds, and temperature. Area 10-30 km outside the shipping lanes will be prone to contaminant concentrations corresponding to 1 : 1,000,000 dilution which was deemed harmful for most sensitive endpoints of WET experiments. Studies for the Saronikos Gulf (Aegean Sea) revealed that the EGCS effluent dilution rate exceeded the 1 : 1,000,000 ratio 70% of the time at a distance of about 10 km from the port. This was also observed for 15% of the time within a band of 10 km wide along the shipping lane extending 500 km away from the port of Piraeus. When mortality of adult specimens of one of the species (copepod Acartia tonsa) was used as an endpoint it was found to be 3-4 orders of magnitude less sensitive to EGCS effluent than early life stage endpoints like fertilisation of eggs and larval development. Mortality of Acartia tonsa is commonly used in standard protocols for ecotoxicological studies, but our data hence shows that it seriously underestimates the ecologically relevant toxicity of the effluent. The same is true for two other commonly used and recommended endpoints, phytoplankton growth and inhibition of bioluminescence in marine bacteria. Significant toxic effects were reached only after addition of 20-40% effluent. A marine environmental risk assessment was performed for the Öresund region for baseline year 2018, where Predicted Environmental Concentrations (PECs) of open loop effluent discharge water were compared to the PNEC value. The results showed modelled concentrations of open loop effluent in large areas to be two to three orders of magnitude higher than the derived PNEC value, yielding a Risk Characterisation Ratio of 500-5000, which indicates significant environmental risk. Further, it should be noted that between 2018-2022 the number of EGCS vessels more than quadrupled in the area from 178 to 781. In this work, the EGCS discharges of the fleet in the Baltic Sea, North Sea, the English Channel, and the Mediterranean Sea area were studied in detail. The assessments of impacts described in this document were performed using a baseline year 2018 and future scenarios. These were made for the year 2050, based on different projections of transport volumes, also considering the fuel efficiency requirements and ship size developments. From the eight scenarios developed, two extremes were chosen for impact studies which illustrate the differences between a very high EGCS usage and a future without the need for EGCS while still compliant to IMO initial GHG strategy. The scenario without EGCS leads to 50% reduction of GHG emissions using low sulfur fuels, LNG, and methanol. For the high EGCS adoption scenario in 2050, about a third of the fleet sailing the studied sea areas would use EGCS and effluent discharge volumes would be increased tenfold for the Baltic Sea and hundredfold for the Mediterranean Sea when compared to 2018 baseline discharges. Some of the tested species, mainly the copepods, have a central position in pelagic food webs as they feed on phytoplankton and are themselves the main staple food for most fish larvae and for some species of adult fish, e.g., herring. The direct effect of the EGSE on invertebrates will therefore have an important indirect effect on the fish feeding on them. Effects are greatest in and near shipping lanes. Many important shipping lanes run close to shore and archipelago areas, and this also puts the sensitive shallow water coastal ecosystems at risk. It should be noted that no studies on sub-lethal effects of early 19 life stages in fish were included in the EMERGE project, nor are there any available data on this in the scientific literature. The direct toxic effects on fish at the expected concentrations of EGCS effluent are therefore largely unknown. According to the regional modelling studies, some of the contaminants will end up in sediments along the coastlines and archipelagos. The documentation of the complex chemical composition of EGCS effluent is in sharp contrast to the present legislation on threshold levels for content in EGCS effluent discharged from ships, which includes but a few PAHs, pH, and turbidity. Traditional assessments of PAHs in environmental and marine samples focus only on the U.S. Environmental Protection Agency (EPA) list of 16 priority PAHs, which includes only parent PAHs. Considering the complex PAHs assemblages and the importance of other related compounds, it is important to extend the EPA list to include alkyl-PAHs to obtain a representative monitoring of EGCS effluent and to assess the impact of its discharges into the marine environment. An economic evaluation of the installation and operational costs of EGCS was conducted noting the historical fuel price differences of high and low sulfur fuels. Equipment types, installation dates and annual fuel consumption from global simulations indicated that 51% of the global EGCS fleet had already reached break-even by the end of 2022, resulting in a summarised profit of 4.7 billion €2019. Within five years after the initial installation, more than 95% of the ships with open loop EGCS reach break-even. The pollutant loads from shipping come both through atmospheric deposition and direct discharges. This underlines the need of minimising the release of contaminants by using fuels which reduce the air emissions of harmful components without creating new pollution loads through discharges. Continued use of EGCS and high sulfur fossil fuels will delay the transition to more sustainable options. The investments made on EGCS enable ships to continue using fossil fuels instead of transitioning away from them as soon as possible as agreed in the 2023 Dubai Climate Change conference. Continued carriage of residual fuels also increases the risk of dire environmental consequences whenever accidental releases of oil to the sea occur.
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van Gemert, Rob, Per Holliland, Konrad Karlsson, Niklas Sjöberg, and Torbjörn Säterberg. Assessment of the eel stock in Sweden, spring 2024 : fifth post-evaluation of the Swedish eel management. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2024. http://dx.doi.org/10.54612/a.4iseib7eup.

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For decades, the population of the European eel has been in severe decline. In 2007, the European Union decided on a Regulation establishing measures for the recovery of the stock, which obliged Member States to implement a national Eel Management Plan by 2009. Sweden submitted its plan in 2008. According to the Regulation, Member States shall report regularly to the EU-Commission, on the implementation of their Eel Management Plans and the progress achieved in protection and restoration. The current report provides an assessment of the eel stock in Sweden as of spring 2024, intending to feed into the national reporting to the EU in August this year. This report updates and extends previous evaluation reports by Dekker (2012, 2015) and Dekker et al. (2018, 2021). In this report, the impacts on the stock - of fishing, restocking and mortality related to hydropower generation - are assessed. Other anthropogenic impacts (climate change, pollution, increased impacts of predators, spread of parasites, disruption of migration due to disorientation after transport, and so forth) probably have an impact on the stock too, but these factors are hardly quantifiable, and no management targets have been set. For that reason, and because most factors were not included in the EU Eel Regulation, these other factors are not included in this report. Our focus is on the quantification of silver eel biomass escaping from continental waters towards the ocean (current, current potential and pristine) and mortality risks endured by those eels during their whole lifetime. The assessment is broken down on a geographical basis, with different impacts dominating in different areas (west coast, inland waters, Baltic coast). In the last decade, a break in the downward trend in glass eel recruitment has been observed, with recruitment no longer declining consistently. Whether that relates to recent protective actions, or is due to other factors, is yet unclear. Nevertheless, recruitment levels remain at historically low levels. This report contributes to the required international assessment, but does not discuss the causing factors behind the recent recruitment trend and the overall status of the stock across Europe. For the different assessment areas, results summarise as follows: On the west coast, a commercial fyke net fishery on yellow eel was exploiting the stock, until this fishery was completely closed in spring 2012. A fishery-based assessment no longer being achievable, we present trends from research surveys (fyke nets). Insufficient information is currently available to assess the recovery of the stock in absolute terms. Obviously, current fishing mortality is zero (disregarding the currently unquantifiable effect of illegal fishing), but none of the other requested stock indicators (current, current potential and pristine biomass) can be presented. The formerly exploited size-classes of the stock show a recovery in abundance after the closure of the commercial fishery, and the smaller size classes show a break in their decline in line with the recent global trend of glass eel recruitment. In order to support the recovery of the stock, or to compensate for anthropogenic mortality in inland waters, young eel has been restocked on the Swedish west coast since 2010. Noting the quantity of restocking involved, the expected effect (ca. 50 t silver eel) is relatively small, and hard to verify – in comparison to the potential natural stock on the west coast (an order of 1000 t). However, for the currently depleted stock, the contribution will likely constitute a larger share of silver eel escapement. For inland waters, this report updates the 2021 assessment, with substantial changes in methodology being the use of a new natural recruitment model, and the full separation of Trap &amp; Transport catches from the fisheries statistics. The assessment for the inland waters relies on a reconstruction of the stock from information on the youngest eels in our waters (natural recruits, assisted migration, restocking). Based on 78 years of data on natural recruitment into 22 rivers, a statistical model is applied which relates the number of immigrating young eel caught in traps to the location and size of each river, the distance from the trap to the river mouth, and the year in which those eels recruited to continental waters as a glass eel (year class). The further into the Baltic, the larger and less numerous recruits generally are. Distance upstream comes with less numerous recruits. Using the results from the above recruitment analysis, in combination with historical data on assisted migration (young eels transported upstream within a drainage area, across barriers) and restocking (young eels imported into a river system), we have a complete overview of how many young eels recruited to Swedish inland waters. From this, the production of fully grown silver eel is estimated for every lake and year separately, based on best estimates of growth and natural mortality rates. Subtracting the catch made by the fishery (as recorded) and down-sizing for the mortality incurred when passing hydropower stations (percentwise, as recorded or using a default percentage), an estimate of the biomass of silver eel escaping from each river towards the sea is derived. Results indicate, that since 1960, the production of silver eel in inland waters has declined from over 700 to below 300 tonnes per year (t/yr). The production of naturally recruited eels is still falling; following the increase in restocking since 2010, an increase in restocking-based production is expected to be starting right around now. Gradually, restocking has replaced natural recruitment (assisted and fully natural), now making up over 90 % of the inland stock. Fisheries have taken 20-30 % of the silver eel (since the mid-1980s), while the impact of hydropower has ranged from 25 % to 60 %, depending on the year. Escapement is estimated to have varied from 72 t in the late 1990s, to 175 t in the early 2000s. The biomass of current escapement (including eels of restocked origin) is approximately 15 % of the pristine level (incl. restocked), or almost 30 % of the current potential biomass (incl. restocked). This is below the 40 % biomass limit of the Eel Regulation, and anthropogenic mortality (70 % over the entire life span in continental waters) exceeds the limit implied in the Eel Regulation (60 % mortality, the complement of 40 % survival). Mortality being that high, Swedish inland waters currently do not contribute to the recovery of the stock. The temporal variation (in production, impacts and escapement) is partly the consequence of a differential spatial distribution of the restocking of eel over the years. The original natural (not assisted) recruits were far less impacted by hydropower, since they could not climb the hydropower dams when immigrating. Since 2010, inland restocking is increasingly concentrated to drainage areas falling to the Kattegat-Skagerrak, also including obstructed lakes (primarily Lake Vänern, and many smaller ones). Even though Trap &amp; Transport of silver eel - from above barriers towards the sea - has contributed to reducing the hydropower impact, hydropower mortality remains the largest estimated contributor to silver eel mortality in inland waters. Without restocking, the biomass affected by fishery and/or hydropower would be only 5-10 % of the currently impacted biomass, but the stock abundance would reduce from 15 % to less than 3 % of the pristine biomass. In summary: the inland eel stock biomass is below the minimum target, anthropogenic impacts exceed the minimum limit that would allow recovery, and those impacts have been increasing. It is therefore recommended to reconsider the current action plans on inland waters, taking into account the results of the current, comprehensive assessment. For the Baltic coast, the 2021 assessment has been updated without major changes in methodology. Results indicate that the impact of the fishery continues to decline over the decades. The current impact of the Swedish silver eel fishery on the escapement of silver eel along the Baltic Sea coast is estimated at 0.3 %. However, this fishery is just one of the anthropogenic impacts (in other areas/countries) affecting the eel stock in the Baltic, including all types of impacts, on all life stages and all habitats anywhere in the Baltic. Integration with the assessments in other countries has not been achieved. Current estimates of the abundance of silver eel (biomass) indicates an order of several thousand tonnes, but those estimates are extremely uncertain, due to the low impact of the fishery (near-zero statistics). Moreover, these do not take into account the origin of those silver eels, from other countries. An integrated assessment for the whole Baltic will be required to ground-truth these estimates. This would also bring the eel assessments in line with the policy to regionalise stock assessments for other (commercial) fish species (see https://ec.europa.eu/oceans-and-fisheries/fisheries/rules/multiannual-plans_en). It is recommended to develop an integrated assessment for the entire Baltic Sea eel stock, and to coordinate protective measures with other range states.
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