There is an increasing trend in consideration of the electricity-supply quality in modern power systems. One of the quality-related aspects is the desired level of Reliability at the points of electrical-energy consumption or Load points. In this regard, the system operator needs to evaluate the impact of system components on the Reliability at the considered Load points. “ Reliability importance” is a quantitative index in order to measure this impact. The Reliability importance measure in most of the conventional methods is on the basis of the risk sensitivity analysis. Such an analysis imposes prohibitive computational burden in large power systems. Considering these points, this paper proposes an approach to evaluate the Reliability importance, which is not suffered from the immense computational burden. The proposed method determines the Reliability importance of the electrical-energy producers or generators from the consumers or Load points perspective in a selected area of the power system. In order to do so, generators are ranked according to their impact on the mentioned area. This impact is measured on the basis of the effect of generators on power-flows in the lines which cross-boundary of the selected area. Capacity and unavailability of the generators are also considered in the ranking calculations. Applicability and computational efficiency of the proposed method is validated through studies conducted on two test systems.

The progressive application of non-linear Loads in distribution systems (DS) increases current harmonics flow in DS's apparatuses, especially distribution transformers (DTs). Since DTs' operating temperature rises due to the harmonics flow, their Loading should be reduced such that the hot spot temperature (HST) is preserved under its permissible value. This means that DTs' available capacity is influenced by Load harmonic content. In this paper, a novel formulation for DTs' failure rate in the presence of harmonics is presented as a function of Load harmonic contents. Using the suggested equivalent failure rate, DTs' available capacity in harmonic polluted DS is mathematically formulated. Additionally, the presence of the harmonic increases the HST, leading to DTs' aging acceleration. Therefore, the impact of harmonic components on DTs' aging is arithmetically modeled. To evaluate the efficacy of the suggested Reliability model, it is applied to three distinct DTs having respectively industrial, commercial, and residential Loads. The obtained results indicate that the available capacity of DTs with the same rated capacity would be different regarding to their Load harmonic contents. On the other hand, it is comprehended from the achieved results that the aging acceleration factor (Faa) of the DTs increases owing to their Load harmonic contents.

From the optimization point of view, an optimum solution of the unit commitment problem with Reliability constraints can be achieved when all constraints are simultaneously satisfied rather than sequentially or separately satisfying them. Therefore, the Reliability constraints need to be appropriately formulated in terms of the conventional unit commitment variables. In this paper, the Reliability-constrained unit commitment problem is formulated in a mixed-integer program format. Both the unit commitment risk and the response risk are taken into account as the probabilistic criteria of the operating reserve requirement. In addition to spinning reserve of generating units, interruptible Load is also included as a part of operating reserve. The numerical studies using IEEE-RTS indicate the effectiveness of the proposed formulation. The obtained results are presented and the implementation issues are discussed. Two sensitivity analyses are also fulfilled to illustrate the effects of generating unit failure rates and interruption time of interruptible Load.

In this paper, the Reliability based design optimization of columns under buckling Load is investigated using evolutionary structural optimization. To determine the Reliability index, the Hasofer-Lind method is employed and results are compared with the Monte Carlo method. The standard response surface method with central composite design is used to estimate the limit state function. An optimization algorithm for optimal design of columns against buckling with different cross-sections and boundary conditions is presented while keeping the column weight constant.The Taguchi method is used to provide the most suitable levels of the design variables. Then by introducing Reliability constraints into the algorithm, the optimized shape of the column under buckling Load based on Reliability is obtained. Optimized design obtained from Deterministic Optimization (DO) and Reliability Based Design Optimization (RBDO) are compared. Numerical examples show that maximum buckling Load capacity is increased compared to the initial uniform design and also RBDO model is more reliable than DO.

This paper presents a new competitive approach to provide Reliability for distribution system customers. The model is based on the Cournot game and utilizes the Nash equilibrium concept to find the output of the problem. Reliability in the proposed framework is an ancillary service and the customers who participated in the program must pay for Reliability provision. The proposed model also considers regulatory concerns of Reliability insuring the average Reliability of the system is not incurred. Based on the proposed model, customers will compete for their Reliability enhancement considering all the constraints related to the network, regulator and each customer.  The expected outage time for each customer is considered the Reliability index in this paper. The model is investigated in a sample case study and the results show how a customer would behave if they participated in the Reliability improvement program of distribution systems. Our results also show that there would exist a high motivation for both parties (utility and customers) to implement the proposed model for the Reliability enhancement of the distribution system.

Strength measurement of rock requires testing that must be carried out on test specimens with particular sizes in order to fulfill testing standards or suggested methods. Often, the coring process breaks up the weaker core pieces, and they are too small to be used in either index tests or conventional strength tests such as point Load index (Is) and Brazilian tensile strength (BTS). One of the index tests to indirectly determine the rock strength is the block punch index (BPI) test, which requires flat disc specimens without special treatment. This study aimed to evaluate the applicability of the BPI test for predicting the uniaxial compressive strength (UCS), BTS and IS of the sandstones by empirical equations. Also, we have compared the performance of the BPI and IS for predicting the UCS and BTS. It was experimentally shown that BPI is a reliable method for predicting the UCS, BTS and Is of the sandstones under study. Moreover, the results indicate that BPI could be utilized with same importance as Is for predicting the UCS, while predicting the BTS by Is appears to be more reliable than BPI.

Reliability-based topology optimization (RBTO) is used to obtain an optimal topology satisfying given constraints, as well as to consider uncertainties in design variables. Most real structures are subjected to different Load at different time. This is referred to as multiple Load cases. Topology optimization for multiple Load cases can consider Loads applied at the same time or at different times (by using weight factors). This article presents an approach for RBTO using multiple Load cases. The optimal topology obtained by two method in multiple Load cases is compared and also the topology obtained by RBTO compared to that obtained by deterministic topology optimization (DTO). The results show that optimal topology obtained through weight factors is more stable than another method when only one Load is applied.

Background: In spite of many advantages in Lenke classification of adolescent idiopathic scoliosis, the latest study of Richards et al showed that the King classification is better than had been reported recently and the Lenke classification system of adolescent idiopathic scoliosis is less reliable than previously reported.Methods: In this study, we performed a multi-surgeon comparison of these two classification systems. After teaching and discussing all available data of these classification systems with four spine surgeons, a pilot classification was performed. Then, they independently evaluated preoperative radiographs (standing posteroanterior, lateral, and two supine side-bending views) of 99 patients with adolescent idiopathic scoliosis. The results were determined by calculating the average percentage of intraobserver and interobserver agreement. Reliability was quantified using kappa statistics.Findings: The King classification demonstrated good intraobserver and interobserver Reliability, with an intraobserver agreement of 85.8% (kappa coefficient, 0.80). Interobserver percentage of agreement averaged 80.8% (kappa coefficient, 0.74). The complete Lenke classification, combining curve type, lumbar modifier, and sagittal thoracic modifier, demonstrated good Reliability for both intraobserver and interobserver measurements. The intraobserver percentage of agreement averaged 85.8% (kappa coefficient, 0.82). The interobserver percentage of agreement averaged 80.8% (kappa coefficient, 0.77).Conclusion: In this study, with each investigator performing the radiographic measurements, the King and Lenke classifications were almost similar (the Lenke classification had slightly better results). Such better results might be due to more training of this complex classification system. So, because of greater coverage of idiopathic scoliosis curve and usefulness of Lenke classification system, we prefer using this classification system in our center.

In this paper, a formulation is developed for obtaining the optimal trajectory of robot manipulators to maximize the Load carrying capacity for a given point-to-point task. The presented method is based on open loop optimal control. The indirect approach is employed to derive optimality conditions based on Pontryagin's Minimum Principle. The obtained necessary conditions for optimality lead to a two-point boundary-value problem solved via a multiple shooting method with the BVP4C command in MATLABâ Since the carrying payLoad is one of the system parameters, a computational algorithm is developed, which provides the capability of calculating the maximum payLoad for a point-to-point task. The main advantage of this method is obtaining various optimal trajectories with different maximum payLoads and path characteristics by changing the penalty matrices values. To demonstrate the efficiency of the proposed method and algorithm in obtaining the maximum payLoad trajectory, simulation is performed on a two-link manipulator.