Most extremum-seeking control approaches focus solely on the problem of finding the extremum of some unknown, steady-state performance map. However, many industrial applications also have to deal with constraints on operating conditions due to, e.g., actuator limitations, limitations on design or tunable system parameters, or constraints on measurable signals. These constraints, which can be unknown a-priori, may conflict with the otherwise optimal operational condition, and should be taken into account in performance optimization. In this work, we propose a sampled-data extremum-seeking approach for optimization of constrained dynamical systems using barrier function methods, where both the objective function and the constraint function are available through measurement only. We show that, under the assumption that initialization does not violate constraints, the interconnection between a constrained dynamical system and optimization algorithms that employ barrier function methods is stable, the constraints are satisfied, and optimization is achieved. We illustrate the results by means of a numerical example.

We propose a novel triggering policy to implement state-feedback controllers for nonlinear systems via packet-based communication networks. The idea is to generate transmissions between the plant and the controller only when a state-dependent rule has been satisfied for a given amount of time. We refer to this new paradigm as event-holding control, in which a clock variable is thus only running when a state-dependent criterion is verified. This is different from time-regularized event-triggered control, where the clock variable keeps running after each transmission instant until it is reset to zero at the moment a state-based condition is verified. We approach the problem of designing an event-holding controller via emulation. We first synthesize a state-feedback law, which stabilizes the closed-loop system in the absence of the communication network. We then design the event-holding triggering mechanism under a set of general assumptions. The results are applied to two case studies consisting of linear systems and a class of nonlinear systems controlled by backstepping. We also provide a numerical backstepping control example, which demonstrates that the event-holding behaviour can reduce the number of transmissions.

Most emulation-based results in networked control systems rely on a bound on the maximal allowable transmission interval (MATI) under which stability is preserved. However, having only such a MATI condition can lead to conservative results, as large values of transmission intervals may only occur sporadically, while the typical transmission interval is much smaller. In this paper, we therefore propose, in addition to the existence of a MATI, to also impose a bound on the average allowable transmission interval, expressed in terms of a reverse average dwell-time (RADT) condition on the transmission intervals. We provide joint conditions on the RADT and the MATI such that stability of the NCS can still be guaranteed, which can, in addition, lead to significant higher values of the MATI itself. The strengths of these new results are illustrated on a numerical example, showing a 484% improvement of the MATI, while still guaranteeing stability.

We study a class of distributed optimization problems of minimizing the sum of potentially non-differentiable convex objective functions (without requiring strong convexity). A novel approach to the analysis of asynchronous distributed optimization is developed. An iterative algorithm based on dual decomposition and block coordinate ascent is implemented in an edge based manner. We extend available results in the literature by allowing multiple and potentially overlapping blocks to be updated at the same time with non-uniform probabilities assigned to different blocks. Sublinear convergence with probability one is proved for the algorithm under the aforementioned weak assumptions. A numerical example is provided to illustrate the effectiveness of the algorithm.

Value iteration is a method to generate optimal control inputs for generic nonlinear systems and cost functions. Its implementation typically leads to approximation errors, which may have a major impact on the closed-loop system performance. We talk in this case of approximate value iteration (AVI). In this paper, we investigate the stability of systems for which the inputs are obtained by AVI. We consider deterministic discrete-time nonlinear plants and a class of general, possibly discounted, costs. We model the closed-loop system as a family of systems parameterized by tunable parameters, which are used for the approximation of the value function at different iterations, the discount factor and the iteration step at which we stop running the algorithm. It is shown, under natural stabilizability and detectability properties as well as mild conditions on the approximation errors, that the family of closed-loop systems exhibit local practical stability properties. The analysis is based on the construction of a Lyapunov function given by the sum of the approximate value function and the Lyapunov-like function that characterizes the detectability of the system. By strengthening our conditions, asymptotic and exponential stability properties are guaranteed.

geopolitical the definitions. The concept of the book consists of seven chapters: Introduction , Model and Theory , Several Geopolitical Approaches in the Recent Past , Classical Geopolitical Assumptions , Classical Geopolitical Theories, Applications of the Model, Setting the Course for a Rejuvenated Geopolitics , and Annex: Classical Geopolitical Concepts / Theories , Notes and Index . Following an overview of the development of geopolitics, the book introduces us to the history of geopolitics, but also its directions and scholars along two lines. The first line would be an organic, reflected by German concern about scientific laws, which contributed to the survival of states in an increasingly volatile world, with his two scholars Friedrich Ratzel and Rudolf Kjellén. Another would be the geostrategic British and North American interest, through the depicted geographical position of states and regions as a condition of foreign action with Alfred Thayer Mahan, Halford Mackinder, and Nicholas Spykman as their standard bearers. After World War II, these classical directions were exposed to great influence by the alleged connection with General Karl Haushofer and his geopolitical school in Munich as well as the aggression of Adolf Hitler, both directions in promoting war and racism. The book is structured to follow three main goals: first, purpose; constructed classical geopolitical model, second, objective; by its construction it outlines the usefulness and legitimacy of classical geopolitics as an important model of international relations, third, access; listed three ways that will show the benefit of classical geopolitics. Phil Kelly separates the model from theory and its application. Theory and the model are different, first, the theory is part of the second, the model. It lists sixty theories in our geopolitical model. These theories can be used to interpret actions and policies in the field of international relations

<p style="text-align: justify;">The fracture of a part or element of a construction can also be defined as a macroscopic separation of the material that leads to the loss of a solid body load. The fracture is the end result of plastic deformation and occurs when all the potential of the material in terms of elastic and plastic deformation is exhausted. This is the worst case of engineering practices, as it can have great consequences for people and the environment.<br />The study of fractures and their causes began with numerous disastrous failures that caused apart from material damage and loss of human lives. These studies have been going on for years, but despite great knowledge, many of the causes of fractures have not been fully established till now. For this reason, research has led to the development of new methods and new testing procedures in conditions similar to exploitation conditions in order to minimize fracture, especially those sudden and unexpected. In this paper, a brief overview of the types of fractures, fracture testing and possible causes of fractures of metal parts during exploitation will be presented.</p>

The action of forces in the back and abdomen under conditions of loading of different external forces at different bending angles is unexplored area. This paper presents a methodology that enables calculation of the magnitudes of forces in the back and abdominal muscles using the combined techniques of the CATIA software system, appropriate mathematical model and polynomial regression analysis. The person of 180cm in height and 85 kg in weight is loaded with 5 + 5 kg of cargo in both hands, and three cases of bending angles of 150, 300 and 600 relative to the vertical axis are analysed.

In this paper, an analytical calculation of load on bridge crane carts winch wheel loads was performed based on which FEM analysis and topological wheel optimization were performed. After the calculation, a standard wheel diameter was adopted. During FEM analysis in the CAD system, SolidWorks noted that certain surface areas had extremely low stress values, which was the main reason for the topological optimization of the wheel. The topological optimization of the geometric 3D model of the wheel is made in the CAESS ProTOp software, resulting in optimized 3D geometric wheel model. These models offer a number of advantages, such as saving materials to produce, reducing their own weight, balance stress conditions and easy customization model optimized technologies of additive manufacturing. This model of analysis and optimization was performed on the laboratory model of the bridge crane and it is applicable to all types of cranes.

<p style="text-align: justify;">Bearing in mind that the wheel sleeves of motor vehicles are exposed to strong dynamic loads, and knowing that these are very responsible parts of the constructions, the need for permanent researches of the influence of certain variables on the process of production of them is imposed. The prepared part which, in this case, is obtained by forging from the appropriate steel has an important role. The process of forging, implies the appearance of certain errors that can manifest in many ways. Such mistakes, despite rigorous control, are difficult to eliminate completely. The paper deals with prepared parts with errors and their impact on the consistency of the tools, as well as the analysis of the influence of the change in the percentage of some elements on the same.</p>

The effect of pH and initial concentration on the removal of Cu(II) and Ni(II) ions from their monocomponent and two-component aqueous solutions using Na2CO3 as a chemical precipitation agent was investigated in this paper. Monocomponent aqueous solutions  of Cu(II) and Ni(II)  ions with their initial concentrations of 50 and 500 mg/L and two-component aqueous solution with initial concentration of 500 mg/L were prepared. The precipitation was carried out by batch method at room temperature by stirring the solution at 300 rpm for 5 minutes, resulting in the formation of precipitates. The resulting precipitate was separated by filtration from the solution. The experiment proved that Na2CO3 is a good agent for removing Cu(II) and Ni(II) ions from their monocomponent water solutions of 50 and 500 mg/L concentration and two-component water solution with initial concentration of each metal 500 mg/L. The percentage of Cu(II) removal was higher at lower pH values compared to Ni(II) removal.

Six Sigma is a version, a philosophy, a strategy and a set of tools for improvement of the quality services and processes. Till now, this method was mostly used in the world of manufacture. Telecommunication is the industry that is based on the service, where the customers are the main focus, and their needs very often seem unpredictable. In this work, a critical review had been given to the application of the Six Sigma methodology in the department of customers support of a telecom company. Through SWOT analysis, given is a review of the opportunities and challenges of this methodology, and also what is necessary to be changed for this methodology to have a purpose and application in one telecommunication company.

<p style="text-align: justify;">The main focus of this paper is to present the TQM practices of 593 companies in Bosnia and Herzegovina. In addition, our results confirm that there are statistically significant differences in TQM practices between firms in a highly competitive and less competitive environment, as well as between firms with and without ISO certificates. TQM practices do not differ between companies that belong to different groups that we constructed based on their age, location, export-orientation and the firm size. We contribute to the existing body of knowledge by identifying organizational contextual factors that might matter in designing more complex structural models.<br /><br /></p>