In this paper, a novel risk-based, two-objective (technical and economical) optimal reactive Power dispatch method in a wind-integrated Power system is proposed which is more consistent with operational criteria.  The technical objective includes the minimization of the new voltage instability risk index. The economical objective includes cost minimization of reactive Power generation and active Power loss. The proposed voltage instability risk employs a hybrid possibilistic (Delphi-Fuzzy)-probabilistic approach that takes into consideration the operator’s experience, the wind speed and demand forecast uncertainties when quantifying the risk index. The decision variables are the reactive Power resources of the system. To solve the problem, the modified multi-objective particle swarm optimization algorithm with sine and cosine acceleration coefficients is utilized. The method is implemented on the modified IEEE 30-bus system. The proposed method is compared with those in the previously published literature, and the results confirm that the proposed risk index is better at estimating the voltage instability risk of the system, especially in cases with severe impact and low probability. In addition, according to the simulation results compared to typical security-based planning, the proposed risk-based planning may increase the security and economy of the system due to better utilization of system resources.

Power is one of the basic concepts of international relations. This concept, which means the actor's ability to achieve the desired results, is applied in different ways; including hard, soft and smart. With the growing Power of the media, the dynamism of the relations between the great Powers, and also their competition for more influence and Power, another concept of Power has emerged, which is called "Sharp Power". In recent years, China has used various tactics and techniques to manipulate and attract public attention at home and abroad to advance its goals and objectives in the international and regional arenas, which some analysts have described as "Sharp Power. " They believe that China, using its party ideology, monitors the media, universities, leaders, politicians, and Western research and economic centers, and seeks to manage and limit what is being said and published about China. Behind all these actions, there are ideological, geopolitical and economic goals and objectives. This article, while explaining the concept of "Sharp Power", seeks to examine why and how China uses this method of exercising Power to advance its foreign policy goals.

In this paper, a new method for extending and relaxing the noise-coupling (NC) technique is proposed to enhance the noise-shaping order without adding the number of integrators. The noise-shaping order of the introduced ∑∆ modulator whit applying a second-order noise-coupling technique is enhanced and its performance with optimizing the noise transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, Power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new noise-coupling method is used to achieve the three-order noise shaping to increase the resolution with low complexity and low-Power. The results show an outstanding improvement in signal-to-noise and distortion ratio (SNDR) compared to the conventional structure.

We introduce the notions of Sasaki mapping and of Sharp elements on a d0-algebra. We investigate the relationships of Sharp elements with Sasaki mappings and with central elements, thus generalizing some results known for D-lattices. Namely, we give a characterization of Sharp elements, by means of Sasaki mappings, which extends a result of Bennett and Foulis; we also prove that an element is central if and only if it is a Sharp element and every element is compatible with it: this generalizes a result of Riecanová.

Please click on PDF to view the abstract

In this paper some upper and lower bounds for the greatest eigenvalues of the PI and vertex PI matrices of a graph G are obtained. Those graphs for which these bounds are best possible are characterized.

Truncated weirs are used to measure flow rate and control water surface upstream, in irrigation canals and laboratory flumes. The main advantages of such weirs are the ease of construction and the capability of measuring a wide range of flows with sufficient accuracy. The hydraulic performance of truncated weirs has not been widely investigated, and not sufficiently documented in the literature. This paper presents the results of an analytical and experimental study on flows over Sharp-crested, truncated-900 triangular weirs with different side construction ratios (b/B= 1, 0.7, 0.5, 0.3). One-dimensional flow equation is presented from the integration of both analytical and physical based solutions. A coefficient of discharge has been introduced to represent the complex functions in the equation and to overcome any uncertainties. Intensive experiments were carried out to evaluate the discharge coefficient in terms of the most significant parameters such as: the geometry of the weir, upstream head and tail water levels, artificial aeration of the weir on downstream face. The results are presented in the form of non-dimensional figures from which the flow rate can be calculated in conjunction with the proposed flow equation. The present results indicate that (1) truncated weirs designed within the limitations from this study can be used as flow measuring structures with sufficient accuracy up to ±5%; (2) stability and accuracy of this measuring system are achieved where the threshold condition of  (h >20 mm) or (h/P1 >0.1) are provided; (3) weirs with side contraction of (b/B³ 0.5) are more efficient; (4) direct evaluation of discharge coefficient, Cd, is not recommended for the condition of submerged flow over the weirs; (5) modular limit of the flow over the weir has to be checked for an accurate evaluation of the flow. This limit is determined in terms of the weir geometry and head water level; (6) in case of the submerged flow, a reduction factor known as submergence coefficient,y , is introduced to evaluate the actual flow rate over the weir in terms of the relative tail and head water levels (t/h), and side contraction ratio (b/B); (7) these types of weirs are efficient enough by a degree of submergence up to t/h< 0.3; (8) artificial aeration has no significant effect on the flow capacity over truncated weirs.