240 research outputs found

    Komparativna analiza primjene optimalnog upravljanja za automatsko upravljanje sustavima za proizvodnju električne energije

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    In this study, an attempt is made to present the application and comparative performance analysis of optimal control approach for automatic generation control (AGC) of electric power generating systems. Optimal controller is designed utilizing performance index minimization criterion. To conduct the study, various single and multi-area models with/without system nonlinearities from the literature are simulated under sudden load perturbation. In this comparative study, to corroborate the worth of optimal controller, the performance of optimal AGC controller is compared with that of I/PI controller optimized adopting recently published the best established techniques such as teacher learning based optimization (TLBO), differential evolution (DE), genetic algorithm (GA), particle swarm optimization (PSO), hybrid bacteria foraging optimization algorithm-PSO (hBFOA-PSO), craziness based PSO (CBPSO), firefly algorithm (FA), krill herd algorithm (KHA), moth-flame optimization (MFO), glow swarm optimization (GSO), simulated annealing (SA), bat algorithm (BA), stochastic fractal search (SFS) and hybrid SFS-local unimodal sampling (hSFS-LUS) technique. The simulated results are compared in terms of settling time (ST), peak undershoot (PU)/overshoot (PO), various performance indices (PIs), minimum damping ratio and system eigenvalues. A sensitivity study is conducted to certify the robustness of optimal controller.U ovom radu se razmatra primjena i komparativna analiza sustava za automatsko planiranje proizvodnje proizvođača električne energije. Sinteza optimalnog regulatora proporcionalno-integralne strukture je provedena koriÅ”tenjem integralnih kriterija. Različiti modeli s jednim područjem i viÅ”e područja te s i bez nelinearnosti koriÅ”teni su u simulaciji nagle promjena opterećenja. Kako bi se pokazala važnost optimalnog regulatora, u komparativnoj analizi su performanse dizajniranog optimalnog regulatora uspoređene s peformansama postignutim koriÅ”tenjem I i PI regulatora sintetiziranih primjenom postojećih uobičajeno koriÅ”tenih metoda kao Å”to su "teacher learning optimization", diferencijska evolucija, genetski algoritam, optimizacija rojem čestica, "hybrid bacteria foraging" optimizacijski algoritam, "craziness based" optimizacija rojem čestica, "firefly" algoritam, "krill herd" algoritam, "moth-flame" optimizacija, "glow swarm" optimizacija, metoda simuliranog kaljenja, "bat" algoritam, stohastično fraktalno traženje (eng. "stochastic fractal search", SFS) i metoda hibridnog SFS lokalnog unimodalnog uzorkovanja. Performanse primijenjenih algoritama upravljanja vrednovani su usporedbom ostvarenih vremena ustaljivanja, iznosa podbačaja i prebačaja te drugih pokazatelja performansi, minimalnih relativnih koeficijentima priguÅ”enja i svojstvenih vrijednosti sustava upravljanja. Provedena analiza osjetljivosti potvrđuje robusnost parametara optimalnog regulatora za Å”irok raspon radnih točaka i parametara sustava

    Biochar: A Sustainable Approach for Improving Plant Growth and Soil Properties

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    Soil is the most important source and an abode for many nutrients and microflora. Due to rapid depletion of agricultural areas and soil quality by means of ever-increasing population and an excessive addition of chemical fertilizers, a rehabilitated attention is a need of the hour to maintain sustainable approaches in agricultural crop production. Biochar is the solid, carbon-rich material obtained by pyrolysis using different biomasses. It has been widely documented in previous studies that, the crop growth and yield can be increased by using biochar. This chapter exclusively summarizes the properties of biochar, its interaction with soil microflora, and its role in plant growth promotion when added to the soil

    Atypical symptoms with typical signs in a patient with Propionibacterium acnes related mitral valve endocarditis

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    Infective endocarditis (IE) is a serious medical condition associated with an increase in morbidity and mortality if not treated promptly and adequately. The clinical outcome depends on the early diagnosis and aggressiveness of the causative organism. Patients usually present with typical features suggestive of Infective endocarditis but in some circumstances the presentations are atypical, and if not diagnosed and treated, may lead to serious consequences. We present a case of atypical presentations of infective endocarditis caused by Propionibacterium acnes organism with no classical features of endocarditis and had symptoms suggestive of urinary tract infection. The diagnosis of IE can be very difficult in patients with atypical clinical presentation, particularly caused by low-pathogenicity organisms. Appropriate clinical assessment and high level of suspicious especially in the patients with previous history of infective endocarditis or having prosthetic valves in situ is crucial

    Papillary fibroelastoma of aortic valve: Early diagnosis and surgical management

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