CANFIS based DSTATCOM modelling for solving power quality problems

Devolution of the power grid into smart grid was necessitated by the proliferation of sensitive load profiles into the system, as well as incessant environmental challenges. These two factors culminated into aggravated disturbances that cause serious havoc along the entire system structure. The traditional proportional-plus-integral-plus-derivative (PID) solution offered by the distribution synchronous compensator (DSTATCOM) could no longer hold. As such, this paper proposes some soft-computing framework for redesigning DSTATCOM to automatically deal with power quality (PQ) problems in smart distribution grids. A recipe of artificial neural network (ANN) and coactive neuro-fuzzy inference systems (CANFIS) was fabricated for the objective. The system was modelled, simulated, and validated in MATLAB/Simulink SimPowerSystems environment. The performance of the CANFIS against adaptive neuro-fuzzy inference systems (ANFIS), ANN and fuzzy logic controllers’ algorithms proved superior in handling PQ issues like voltage sag, voltage swell and harmonics

Семантичне навантаження силенціального ефекту в музичному дискурсі (на матеріалі англомовних художніх текстів)

У статті порушується питання адгерентності мовних та музичних знаків. Фокусується увага на ословленні музичних ефектів засобами художньої прози. Намічаються перспективи подальшого наукового пошуку. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/408

Prevalence and determinants of cardiac arrhythmias and conduction anomalies in adults aged ≥ 40 years in Jimma Town, Southwest of Ethiopia: a cross-sectional study

Background: The prevalence of cardiac arrhythmia (CA) in the Ethiopian population is unknown. A community study was conducted to assess the magnitude and predictors of CAs in adults aged≥40 years in Jimma Town. Methods: A community-based cross-sectional study was conducted in Jimma town from May to July 2017. A total of 634 adults aged 40 years or older were selected using a systematic sampling technique from six kebeles of the Town. Study participants were screened for CA using a 12-lead ECG machine. Face-to-face interviews, anthropometric, important clinical measurements were performed. Data analysis was done using SPSS for windows version 21.0. Results: A total of 634 study participants, significant CA occurred in 217 individuals (34.2%). Conduction abnormalities and sinus bradycardia were the commonest findings (25.4%). Premature beats (ventricular 1.9%, atrial 1.1%) and atrioventricular nodal reentrant tachycardia (2.1%) were the next most frequent arrhythmias. Arrhythmias were independently associated with smoking(AOR=1.9;P=.047), hypertension(AOR=1.5;P=.02), heart failure(AOR=2.06;P=.023), prior stroke(AOR=4.9;P=.001), previous history of MI(AOR=1.78;P=.039), vigorous intensity activities(AOR=0.56;P=.024), solidified vegetable oil consumption (AOR=3.5;P=.004), and occupation(pensioner, none)[AOR=1.7;P=.017]. Conclusions: CA is highly prevalent in Jimma. Hypertension and history of heart diseases are the most potent predictors of cardiac arrhythmia. Large-scale screening for early detection of arrhythmia has important implications for treatment. Keywords: Cardiac arrhythmia; prevalence; pisk-factors; 12-lead ECG; Jimma Town

Evolutionary optimisation for Volt-VAR power quality control

With the more environmentally friendly smart grid initiatives during the past few years, intelligent operation and optimisation of the electricity distribution system have received an increasing attention in power system research worldwide. Power flow from the distribution substation to the customer can be optimised at Volt-Ampere-Reactive (VAR) level by reducing the reactive power. Distributed Generation (DG) and Renewable Energy Sources (RES) represent both the broadest potentials and the broadest challenges for intelligent distribution systems and smart grid control. In general, the flexibility envisaged by integrating RES during smart grid transformation is often surrounded by nonlinearities such as wave-form deformations caused by harmonic currents or voltages, which impliedly increase control system complexity. Therefore, conventional controllers presently implemented need to be re-engineered in order to solve power quality (PQ) problems therein. This work aims to improve the controllability of Distribution Static Compensators (DSTATCOMs) through the development of improved control systems using evolu- tionary computation enabled design automation and optimisation. The resultant Volt-VAR Control (VVC) optimises PQ in the presence of nonlinearities and uncertainties. It also aims at increasing overall system’s sensitivity to unconsidered parameters in the design stage like measurement noise, unmodelled dynamics and disturbances. This is otherwise known as the robustness of the system offering it with valuable potential for future smart grids control, which are anticipated to present more nonlinearities due to virtual power plant (VPP) configuration. According to European Project FENIX, a Virtual Power Plant (VPP) aggregates the capacity of many diverse Distributed Energy Resources (DER), it creates a single operating profile from a composite of the parameters characterizing each DER and can incorporate the impact of the network on aggregate DER output. To particularly solve PQ problems, two objectives are realised in this thesis. First, a non-deterministic evolutionary algorithm (EA) is adopted to generate optimum fuzzy logic controllers for DSTATCOMs. This design methodology extends the traditional computer-aided-design (CAD) to computer-automated-design (CAutoD), which provides a unified solution to diverse PQ problems automatically and efficiently. While realizing this objective, the prediction ability of the derivative term in a proportional and derivative (PD) controller is improved by placing a rerouted derivative filter in the feedback path to tame ensuing oscillations. This method is then replicated in a fuzzy PD scheme and is automated through the capability of a “generational” tuning using evolutionary algorithm. Fuzzy logic controllers (FLCs) are rule-based systems which are designed around a fuzzy rule base (RB) related through an inference engine by means of fuzzy implication and compositional procedures. RBs are normally formulated in linguistic terms, in the form of if ...then rules which can be driven through various techniques. Fundamentally, the correct choice of the membership functions of the linguistic set defines the performance of an FLC. In this context, a three rule-base fuzzy mapping using Macvicar-Whelan matrix has been incorporated in this scheme to reduce the computational cost, and to avoid firing of redundant rules. The EA-Fuzzy strategy is proven to overcome the limitation of conventional optimisation which may be trapped in local minima, as the optimisation problem is often multi-modal. The second objective of the thesis is the development of a novel advanced model-free predictive control (MFPC) system for DSTATCOMs through a deterministic non-gradient algorithm. The new method uses its “look-ahead” feature to predict and propose solutions to anticipated power quality problems before they occur. A describing function augmented DSTATCOM regime is so arranged in a closed-loop fashion to locate limit cycles for settling the systems nonlinearities in a model-free zone. Predictive control is performed upon the online generated input-output data-set through the power of a non-gradient simplex algorithm. The strategy is to boycott the usage of a system model which is often based on gradient information and may thus be trapped in a local optimum or hindered by noisy data. As a model-free technique, the resultant system offers the advantage of reduction in system modelling or identification, which is often inaccurate, and also in computational load, since it operates directly on raw data from a direct online procession while at the same time dealing with a partially known system normally encountered in a practical industrial problem. Steady-state and dynamic simulations of both control and simulation models in Matlab/Simulink environment demonstrate the superiority of the new model-free approach over the traditional trial-and-error based methods. The method has been varified to offer faster response speed and shorter settling time at zero overshoot when compared to existing methods. A SimPowerSystems software simulation model is also developed to check experimental validity of the designs. Where specific PQ problems such as harmonics distortion, voltage swells, voltage sags and flicker are solved. A noticeable record level of THD reduction to 0.04% and 0.05% has respectively been achieved. It is therefore safe to recommend to the industry the implementation of this model-free predictive control scheme at the distribution level. As the distribution system metamorphoses into decen- tralised smart grid featuring connectivity of virtual power plants mostly through power electronic converters, e.g., DSTATCOM, it stands to benefit from the full Volt-VAR automated controllability of the MFPCs low control rate. Based on CAutoD, the practical implementation of this technique is made possible through digital prototyping within the real-time workshop to automatically generate C or C++ codes from Simulink, which executes continuous and discrete time models directly on a vast range of computer applications. Its overall wired closed-loop structure with the DSTATCOM would offer reliable and competitive advantages over its PID and SVC (CAD-based) counterparts currently being implemented through physical prototyping, in terms of; quick product-to-market pace, reduced hardwire size, small footprint, maintenance free as it is model-free (and automated), where pickling the controller timers and model contingencies are unnecessary as would be with the conventional controllers. More importantly, the scheme performs the aforementioned control functions robustly at a high speed in the range of 0.005 → 0.01 seconds. High enough to capture and deal with any ensuing PQ problem emanating from changes in customer’s load and system disturbances in an environmentally friendly, but less grid-friendly renewable generators

Analysis of Vertical Ground Reaction Force Variables during a Sit to Stand Task in Participants Recovering from a Hip Fracture

Background: A Sit to Stand task following a hip fracture may be achieved through compensations (e.g. bilateral arms and uninvolved lower extremity), not restoration of movement strategies of the involved lower extremity. The primary purpose was to compare upper and lower extremity movement strategies using the vertical ground reaction force during a Sit to Stand task in participants recovering from a hip fracture to control participants. The secondary purpose was to evaluate the correlation between vertical ground reaction force variables and validated functional measures. Methods: Twenty eight community dwelling older adults, 14 who had a hip fracture and 14 control participants completed the Sit to Stand task on an instrumented chair designed to measure vertical ground reaction force, performance based tests (Timed up and go, Berg Balance Scale and Gait Speed) and a self report Lower Extremity Measure. A MANOVA was used to compare functional scales and vertical ground reaction force variables between groups. Bivariate correlations were assessed using Pearson Product Moment correlations. Findings: The vertical ground reaction force variables showed significantly higher bilateral arm force, higher uninvolved side peak force and asymmetry between the involved and uninvolved sides for the participants recovering from a hip fracture (Wilks\u27 Lambda=3.16, P=0.019). Significant correlations existed between the vertical ground reaction force variables and validated functional measures. Interpretation: Participants recovering from a hip fracture compensated using their arms and the uninvolved side to perform a Sit to Stand. Lower extremity movement strategies captured during a Sit to Stand task were correlated to scales used to assess function, balance and falls risk

Cosmic ray particle detectors designed for interplanetary studies utilizing the Pioneers 8, 9, and 10 spacecrafts Final report

Design and performance of cosmic ray detector packages for Pioneer space probe

Use of Denosumab in Children With Osteoclast Bone Dysplasias: Report of Three Cases.

Denosumab has been used successfully to treat disease-associated osteoclast overactivity, including giant cell tumor of bone. Given its mechanism of action, denosumab is a potent potential treatment of other osteoclast bone dysplasias including central giant cell granuloma (CGCG), aneurysmal bone cyst (ABC), and cherubism. Relatively little is known about the safety and efficacy of denosumab in patients with these conditions, especially in children. We report on 3 pediatric patients treated with denosumab over a 3-year period at UCLA Medical Center (Los Angeles and Santa Monica, CA, USA): a 12-year-old with recurrent ABC of the pelvis, a 14-year-old with CGCG of the mandible, and a 12-year-old with cherubism. All were started on a 1-year course of 15 doses 120 mg s.c., given monthly with two loading doses on day 8 and 15. All patients demonstrated rapid and pronounced clinical improvement while on denosumab, including a significant reduction in pain and sclerosis of lytic lesions on radiographs. Within 1 month of initiating therapy, 2 patients experienced hypocalcemia (Common Terminology Criteria for Adverse Events [CTCAE] grade 2) and hypophosphatemia, with 1 patient experiencing symptoms. One patient went on to experience symptomatic rebound hypercalcemia (CTCAE grade 4) 5 months after completing therapy, requiring bisphosphonates and calcitonin. For the second patient, we developed a schedule to wean denosumab involving the progressive lengthening of time between doses from 1 to 4 months in 1-month increments before cessation. We found that denosumab therapy results in significant clinical and radiographic improvement for pediatric patients with nonresectable ABC, CGCG, and cherubism. Problems with serum calcium may be more common in younger patients, with symptomatic and protracted rebound hypercalcemia after cessation of therapy the most significant. We present a potential solution to this problem with progressive spacing of doses. Potential serious adverse events from alterations in calcium homeostasis should be explored in prospective clinical trials. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research