University of Niš: Facta Universitatis (E-Journals) / Универзитет у Нишу
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OPTIMIZING FRACTIONAL ORDER PID CONTROLLER FOR DC MOTOR SPEED CONTROL USING ARTIFICIAL HUMMINGBIRD ALGORITHM
Get PDFThis study implements the artificial hummingbird algorithm (AHA) to tune the FOPID controller optimally for DC motor speed control. The AHA algorithm is a straightforward and efficient method that mathematically simulates the foraging strategies of hummingbirds. It has been specifically designed to tackle a wide range of optimisation challenges. For a fair comparison, the proposed AHA-FOPID controller is tuned using the ITAE objective function and evaluated alongside the controllers optimized through GWO, PSO, and DE in the previous researches. Additionally, transient response analysis and load disturbance analysis are conducted. The suggested controller exhibits exceptional transient performance, as seen by a settling time of 0.0329 seconds, a rising time of 0.0208 seconds, and no overshoot. The simulation findings are encouraging and confirm the efficacy of the proposed technique. Ultimately, a statistical analysis is conducted to confirm the superiority of the proposed method
ON RICCI SEMI-SYMMETRIC MIXED QUASI-EINSTEIN HERMITIAN MANIFOLD
Get PDFThe object of the present paper is to study Bochner Ricci semi-symmetric mixed quasi-Einstein Hermitian manifold and holomorphically projective Ricci semisymmetric mixed quasi-Einstein Hermitian manifold
ON CONFORMALLY FLAT p-POWER (alpha,beta)-METRICS
No full textThe purpose of this paper is to study the class of conformally flat p-power (alpha,beta)-metrics F = alpha(1 + beta/alpha)^p, where p ̸= 0 is a constant. This metric is interesting, because for p = -1; 1/2; 1; 2 it reduces to the Matsumoto, square-root, Randers, and square metric, respectively. We prove that if a p-power (alpha,beta)-metric has relatively isotropic mean Landsberg curvature, then it is either a Riemannian metric or a locally Minkowski metric
ROUGH STATISTICAL CONVERGENCE OF SEQUENCES IN A PARTIAL METRIC SPACE
Get PDFIn this paper, using the concept of natural density, we have introduced the notion of rough statistical convergence which is an extension of the notion of rough convergence in a partial metric space. We have defined the set of rough statistical limit points of a sequence in a partial metric space and proved that this set is closed and bounded. Finally, we have found out the relationship between the set of statistical cluster points and the set of rough statistical limit points of sequences in a partial metric space
ALMOST SCHOUTEN SOLITONS ON N -CONTACT METRIC MANIFOLDS
No full textIn the current paper, we have studied almost Schouten solitons and gradient Schouten solitons on an -Contact metric manifold of dimension . Besides, we have shown that the almost Schouten soliton does not exist on -Contact metric manifold for . In addidtion, it has been proved that the manifold complying with the gradient Schouten solitons only when it is an almost -Contact metric manifold. Moreover,we have determined that a -dimensional -Contact metric manifold admitting a gradient Schouten soliton is either flat or of constant scalar curvature. Finally, an example has been conducted to verify the outcomes
DOMINATION NUMBER AND WATCHING NUMBER OF SUBDIVISION CONSTRUCTION OF GRAPHS
Get PDFIn light of the results of a domination number of the subdivision of a graph G, we determine an upper bound of the watching number of S(G). In addition, we obtain a condition with which the upper bound becomes sharp
INNOVATIVE DESIGN STRATEGY FOR AN INTERNAL COMBUSTION ENGINE WITH IMPROVED OUTPUT CHARACTERISTICS
Get PDFThe paper describes the concept of a new internal combustion engine. Presented IC engine concept possesses a variable displacement, variable compression ratio, combustion at constant volume, improved intake and exhaust processes, as well as more complete expansion of the working fluid. A comparison of some performance of this new concept with conventional IC engine and electric motors is provided. The results indicate that the performance of IC engine can still be improved. The achieved efficiency of the engine is over 40%. The Ricardo Wave program was used for simulating the characteristics of the engine. CAD model of concept engine was made with CATIA V5
UTICAJ DNEVNIH VARIJACIJA NA DEFICIT U PROMENI PRAVCA KRETANJA I LINEARNOM DRIBLINGU KOD RUKOMETAŠA
No full textThe present study aims to determine the effect of time-of-day on linear and change‑of‑direction Dribble Deficit in elite male handball players. Sixteen elite male handball players from a Serbian Super League club participated in this study (mean ± SD: age 25.4 ± 5.8 years, body mass 94.0 ± 7.4 kg, stature 193.5 ± 7.5 cm). All participants completed four physical performance tests without a ball (change-of direction Zig-Zag test, 5-m, 10-m and 20-m linear sprints) and four tests with a ball (change-of direction Zig-Zag and 5-m, 10-m and 20-m linear sprints) at two separate testing sessions in the morning (8:00-9:30am) and in the evening (6:00-197:30pm). Dribble Deficit parameters for change-of-direction and linear sprint did not differ significantly between the morning and evening sessions (p = 0.309–0.757). To conclude, in elite male handball players, the Dribble Deficit for both change‑of‑direction and linear sprint tasks remains almost unchanged from early morning to early evening which is important for coaches to organize training sessions.Ova studija je utvrđivala uticaj doba dana na pravolinijski sprint i promenu pravca kretanja elitnih rukometaša. Šesnaest elitnih rukometaša koji nastupaju u Superligi Srbije su učestvovali u ovoj studiji (mean ± SD: uzrast 25.4 ± 5.8 godina, telesna masa 94.0 ± 7.4 kg, visina 193.5 ± 7.5 cm). Svi ispitanici su uradili po četiri testa motoričkih sposobnosti s ai bez lopte (promena pravca kretanja zig-zag, 5m, 10m, 20m pravolinijski sprint) u dva vremenska intervala, jutarnji (8:00-9:30 h) i večernji (18:00-19:30 h). Dribling deficit za promenu pravca kretanja i linearni sprint se statistički značajno ne razlikuju prepodne i uveče (p = 0.309–0.757). Kod elitnih rukometaša dribling deficit za promenu pravca kretanja i pravolinijski sprint ostaju nepromenjenji od ranog jutra do večeri što je važno za trenere u organizaciji treninga
QUANTITATIVE ANALYSIS AND OPTIMIZATION OF ENERGY EFFICIENCY IN ELECTRIC MULTIPLE UNITS
Get PDFThe increasing urgency for sustainable transportation solutions necessitates a thorough examination of energy efficiency within railway systems. This study investigates the energy performance of Siemens Ventus (i.e., Siemens Desiro ML type) electric multiple units on Austria's Raaberbahn network, focusing on route-specific energy consumption and the optimization of regenerative braking. Utilizing data collected from January to May 2023, the research employs a robust methodology that integrates statistical analysis, curve-fitting, and geospatial modeling to assess energy trends along routes connecting Vienna, Bratislava, and Deutschkreutz. The findings reveal that terrain, operational practices, and external environmental factors significantly contribute to energy inefficiencies. Specifically, hotspots of energy overconsumption were identified, leading to the development of tailored optimization models for each route. The analysis also produced heatmaps that illustrate critical spatial and temporal patterns, which are essential for implementing targeted interventions aimed at enhancing energy efficiency
POLYESTER APPAREL CUTTING WASTE AS SOUND INSULATION MATERIAL
Get PDFThis study developed an insulation structure using waste from apparel cutting and examined its sound insulation capabilities. Shredded polyester apparel cuttings served as the primary material for this structure. Results indicate that the insulation made from apparel waste exhibits superior sound absorption properties compared to conventional sound and thermal insulators. The average sound absorption ranged from 54.7% to 74.7% across frequencies from 250 to 2000 Hz. This research proposes a method to reduce environmental pollution by repurposing polyester apparel waste for insulation in roofs and internal walls