Journal articles: 'Shaded system'

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Reilly, Stephanie S. "Mathematical Exploration: All Shades Are the Right Shade." Mathematics Teaching in the Middle School 16, no. 1 (August 2010): 56–60. http://dx.doi.org/10.5951/mtms.16.1.0056.

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Students spend a lot of time in algebra 1 solving linear equations and systems of linear equations. These subtopics of algebra can be problematic and difficult for students to grasp. After months of finding the solution to a linear equation (a line) and finding the solution to a system of linear equations (generally, a point), students struggle with understanding the solution to a linear inequality or a system of linear inequalities (a shaded region). Students might think, Why do we shade at all, what does the shading mean, and why is an overlapping shaded region the solution in an inequalities systems graph?

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Malathy, S., and R. Ramaprabha. "Suitability of Asymmetrical Multilevel Inverters for Partial Shaded Photovoltaic Systems." Applied Mechanics and Materials 622 (August 2014): 173–79. http://dx.doi.org/10.4028/www.scientific.net/amm.622.173.

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The efficiency of building integrated photovoltaic (PV) system is greatly affected by the partial shaded conditions. The impact of shading conditions depends not only on the level of shading but also on other factors like array size, type of configuration adopted, pattern and intensity of the shade. The influence of partial shading is much pronounced in series configuration than any other types due to the absence of cross ties. Unless protected by bypass diodes, the thermal stress across the panel increases under shaded conditions and eventually leads to the development of hot spots that can damage the shaded panel permanently. Bypass diode totally isolates the shaded panel from the rest of the of the array leaving the array underutilized. To address this issue, this paper proposes repositioning of the panels to distribute the shade uniformly all over the array. Besides, a hybrid asymmetric multilevel inverter is proposed for power conversion.

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Westmore, R. J. "Real-time shaded colour polygon generation system." IEE Proceedings E Computers and Digital Techniques 134, no. 1 (1987): 31. http://dx.doi.org/10.1049/ip-e.1987.0006.

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LÓPEZ-SAMPSON, Arlene, Norvin SEPÚLVEDA, Mirna BARRIOS, Eduardo SOMARRIBA, Rodolfo MUNGUÍA, Pedro MORAGA, Alejandro PONCE, Luis OROZCO-AGUILAR, Elvin NAVARRETE, and Ledis NAVARRETE. "Long-term effects of shade and input levels on coffee yields in the Pacific region of Nicaragua." BOIS & FORETS DES TROPIQUES 346 (December 25, 2020): 21–33. http://dx.doi.org/10.19182/bft2020.346.a36292.

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The suitability and profitability of coffee cultivation in Central America are at risk due to pest and disease outbreaks, price fluctuations and climate change. Proper shading is claimed to be one of the most promising practices to seek sustainability and better adapt coffee cultivation to climate change in marginal areas. This study recorded and compared coffee cherry yields over a ten-year period from shaded coffee (N-fixing-trees and timber trees) agroforestry systems under different management regimes (conventional vs. organic) in a suboptimal site. Significant differences in production were detected between conventional inputs vs. combination of organic inputs and shade types in some years of the evaluation period. Full-sun cultivation under intensive management was the most productive system for coffee yields, followed by shaded systems under timber trees. Interestingly, and regardless of management systems (intensive conventional or intensive organic) the worst combinations in terms of coffee yield were shaded systems under leguminous species (Inga laurina (Sw.) Willd. + Simarouba glauca DC.). Across all experimental plots, the timber species Simarouba glauca and Tabebuia rosea (Bertol.) DC. grew well, reaching a mean annual increment in diameter of 2.5-3.3 cm/year (age 12 years). Average gross revenues were higher in full-sun and timber-shaded agroforestry systems. Overall, intensive management regimes were the most expensive cultivation system to run but also the best in terms of coffee yield performance.

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Ghoshroy, Soumitra, and Wayne R. Fagerberg. "Light-detection system in higher-plant chloroplasts : Pigment mediated or energy related." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1668–69. http://dx.doi.org/10.1017/s0424820100132972.

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Light is the driving force of photosynthesis. Plants adapt to rapid changes in irradiance, quality and duration of the light environment by modulating the composition of the thylakoid membranes to make the best use of the available light energy. Each chloroplast contains a large amount of thylakoid membranes some of which may be arranged as stacks (granal thylakoids) and others as unstacked sacks (stromal thylakoids). Shaded chloroplasts develop more thylakoid surface area as compared to those growing in full sunlight. Conversion of sun-type chloroplasts to those of shade-types can occur quickly, when sun plants are shaded. However, the response mechanism of chloroplasts to changes in light levels is yet to be understood. Reports in the literature showed that plants grown in red light developed more grana compared to those grown under blue light and a pigment detection system has been postulated. While, other models propose that overall energy flux changes within the chloroplast induce sun/shade response.

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Waller, Rebekah, Murat Kacira, Esther Magadley, Meir Teitel, and Ibrahim Yehia. "Semi-Transparent Organic Photovoltaics Applied as Greenhouse Shade for Spring and Summer Tomato Production in Arid Climate." Agronomy 11, no. 6 (June 4, 2021): 1152. http://dx.doi.org/10.3390/agronomy11061152.

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Recognizing the growing interest in the application of organic photovoltaics (OPVs) with greenhouse crop production systems, in this study we used flexible, roll-to-roll printed, semi-transparent OPV arrays as a roof shade for a greenhouse hydroponic tomato production system during a spring and summer production season in the arid southwestern U.S. The wavelength-selective OPV arrays were installed in a contiguous area on a section of the greenhouse roof, decreasing the transmittance of all solar radiation wavelengths and photosynthetically active radiation (PAR) wavelengths (400–700 nm) to the OPV-shaded area by approximately 40% and 37%, respectively. Microclimate conditions and tomato crop growth and yield parameters were measured in both the OPV-shaded (‘OPV’) and non-OPV-shaded (‘Control’) sections of the greenhouse. The OPV shade stabilized the canopy temperature during midday periods with the highest solar radiation intensities, performing the function of a conventional shading method. Although delayed fruit development and ripening in the OPV section resulted in lower total yields compared to the Control section (24.6 kg m−2 and 27.7 kg m−2, respectively), after the fourth (of 10 total) harvests, the average weekly yield, fruit number, and fruit mass were not significantly different between the treatment (OPV-shaded) and control group. Light use efficiency (LUE), defined as the ratio of total fruit yield to accumulated PAR received by the plant canopy, was nearly twice as high as the Control section, with 21.4 g of fruit per mole of PAR for plants in the OPV-covered section compared to 10.1 g in the Control section. Overall, this study demonstrated that the use of semi-transparent OPVs as a seasonal shade element for greenhouse production in a high-light region is feasible. However, a higher transmission of PAR and greater OPV device efficiency and durability could make OPV shades more economically viable, providing a desirable solution for co-located greenhouse crop production and renewable energy generation in hot and high-light intensity regions.

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Qing-chi, Wang. "Study on shaded transducer for acoustic scattering system." Chinese Journal of Oceanology and Limnology 17, no. 2 (June 1999): 187–92. http://dx.doi.org/10.1007/bf02842716.

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WILSON, T. D., R. M. BROOK, and H. F. TOMLINSON. "INTERACTIONS BETWEEN NÉRÉ (PARKIA BIGLOBOSA) AND UNDER-PLANTED SORGHUM IN A PARKLAND SYSTEM IN BURKINA FASO." Experimental Agriculture 34, no. 1 (January 1998): 85–99. http://dx.doi.org/10.1017/s0014479798001069.

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A farmer's intercropping system of white sorghum (Sorghum bicolor) and néré (Parkia biglobosa) was studied in Burkina Faso. In quadrats in three differing zones of tree influence, full sun (open field), semi-shade (under the edge of the tree crown) and full shade (under the crown), tree morphology and associated sorghum growth were recorded together with micro-meterological parameters. Mean photosynthetic photon flux density (PFD) was reduced to 51 and 26% of full sun levels, in the semi-shaded and fully shaded quadrats respectively. Soil temperature and moisture were also recorded. In the season studied, the principal effect of the trees on the crop was competition for light. For plants in full shade, total shoot and panicle mass were halved compared with the crop in full sun. However, plants in semi-shade were able to compensate for decreased PFD almost entirely. Measurable compensatory effects were decreased rate of leaf senescence, greater partitioning of resources into leaf production, and larger, thinner leaf laminae. It was concluded that the current farmers' practice of sowing under the crowns of trees produced a worthwhile, if somewhat reduced, crop yield, and that socially, economically and ecologically the sorghum–néré parkland system was worth retaining.

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Dos Santos, Núbia De Fátima Alves, Jamile Andréa Rodrigues Da Silva, Airton Alencar De Araújo, Rinaldo Batista Viana, Alexandre Rossetto Garcia, Andréia Santana Bezerra, Benjamim De Souza Nahúm, and José De Brito Lourenço Júnior. "Silvopastoral Systems Contribute to Water Buffalo Welfare and Normal Behavior Pattern Under Eastern Amazon Conditions." Journal of Agricultural Studies 9, no. 2 (March 25, 2021): 260. http://dx.doi.org/10.5296/jas.v9i2.18022.

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This research aimed to study the behavior of female Murrah buffaloes in a silvopastoral system. The trial was carried out at Embrapa Eastern Amazon, under Afi climate according to the Köppen classification, between August and November 2009, during the less rainy season. Three different periods of the day were considered during activity evaluation: morning period – between 6:00 AM and 9:55 AM; intermediary period – between 10:00 AM and 1:55 PM; and afternoon period – between 2:00 PM and 5:55 PM. The animals were maintained in a silvopastoral system (SPS) (ST; n=10) with shade from Racosperma mangium. The meteorological variables of temperature and relative air humidity were measured, as well as the following animal behavior variables: time grazing, ruminating and idling, time standing and lying, and time in shaded and non-shaded areas. These variables were compared by T test (P<0.05). Air temperatures were higher in the non-shaded area of the SPS. All activities were reduced in the intermediary period, except idling. The grazing and rumination times in the morning were longer in non-shaded areas, while the time idling standing was longer during the intermediary period in shaded areas as a way of avoiding the harmful effects of the intense solar radiation and high air temperatures of the Amazonian humid climate. Hence, SPSs may contribute to animal welfare and increase their productive behavior.

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Wildridge, Ashleigh M., Sergio C. Garcia, Peter C. Thomson, Ellen C. Jongman, Cameron E. F. Clark, and Kendra L. Kerrisk. "The impact of a shaded pre-milking yard on a pasture-based automatic milking system." Animal Production Science 57, no. 7 (2017): 1219. http://dx.doi.org/10.1071/an16491.

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During hot weather cows typically reduce feed intake and actively seek shade and water to reduce the metabolic stress on their bodies. This can have a negative impact on the occurrence of voluntary milking visits to an automatic milking system (AMS) operating with voluntary traffic, thus reducing milking frequency. Shade is known to be effective in alleviating heat stress in dairy cattle; however, the impact of providing shade at the milking facility of a pasture-based AMS on time taken to voluntarily enter a milking unit is unknown. A herd of ~300 lactating cows milked in a pasture-based AMS were divided into two groups during the summer of 2016. Each group spent 4 weeks in a SHADE (predominately shaded pre-milking yard) and a NO-SHADE (predominantly non-shaded pre-milking yard) treatment, with two periods in a crossover design. Cow respiration rates, time spent in pre- and post-milking areas, concentrate consumption and milk yield were recorded. On average, cows in the SHADE treatment were found to take longer to enter the milking unit than did cows in the NO-SHADE treatment (SHADE = 11.40 min, NO-SHADE = 8.70 min, P < 0.001). SHADE was also associated with lower average respiration rates (SHADE = 68 breaths per minute (bpm), NO-SHADE = 73 bpm, P < 0.001), increased concentrate consumption (SHADE = 6.50 kg/cow.day, NO-SHADE = 6.39 kg/cow.day, P = 0.03) and increased milk yield (SHADE = 11.44 kg/cow.milking, NO-SHADE = 10.95 kg/cow.milking, P < 0.001). Overall, SHADE made available to the cows pre-milking appeared to improve cow performance and comfort (as indicated by reduced respiration rates).

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Ramaprabha, R., and S. P. Chitra. "Comparative Analysis of Maximum Power Point Tracking Controllers under Partial Shaded Conditions in a Photovoltaic System." Journal of Engineering Research [TJER] 12, no. 1 (June 1, 2015): 15. http://dx.doi.org/10.24200/tjer.vol12iss1pp15-31.

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Mismatching effects due to partial shaded conditions are the major drawbacks existing in today’s photovoltaic (PV) systems. These mismatch effects are greatly reduced in distributed PV system architecture where each panel is effectively decoupled from its neighboring panel. To obtain the optimal operation of the PV panels, maximum power point tracking (MPPT) techniques are used. In partial shaded conditions, detecting the maximum operating point is difficult as the characteristic curves are complex with multiple peaks. In this paper, a neural network control technique is employed for MPPT. Detailed analyses were carried out on MPPT controllers in centralized and distributed architecture under partial shaded environments. The efficiency of the MPPT controllers and the effectiveness of the proposed control technique under partial shaded environments was examined using MATLAB software. The results were validated through experimentation.

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Yu, Byunggyu, and Seok-Cheol Ko. "Power dissipation analysis of PV module under partial shading." International Journal of Electrical and Computer Engineering (IJECE) 11, no. 2 (April 1, 2021): 1029. http://dx.doi.org/10.11591/ijece.v11i2.pp1029-1035.

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Photovoltaic (PV) generation has been growing dramatically over the last years and it ranges from small, rooftop-mounted or building integrated systems, to large utility scale power stations. Especially for rooftop-mounted PV system, PV modules are serially connected to match with PV inverter input voltage specification. For serially connected PV system, shading is a problem since the shaded PV module reduces the output whole string of PV modules. The excess power from the unshaded PV module is dissipated in the shaded PV module. In this paper, power dissipation of PV module under partial shading is analyzed with circuit analysis for series connected PV modules. The specific current and voltage operating point of the shaded PV module are analyzed under shading. PSIM simulation tool is used to verify the power dissipation analysis. When there is no bypass diode and three solar modules are connected in series, upto 39.1% of the total maximum PV power is dissipated in the shaded PV module. On the other hand, when the bypass is attached, 0.3% of the total maximum power is generated as a loss in the shaded PV module. The proposed analysis technique of shaded PV module could be used in PV system performance analysis, especially for maximum power point tracking (MPPT) performance.

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Hahm, Jehun, Jaeho Baek, Hyoseok Kang, Heejin Lee, and Mignon Park. "Matlab-Based Modeling and Simulations to Study the Performance of Different MPPT Techniques Used for Photovoltaic Systems under Partially Shaded Conditions." International Journal of Photoenergy 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/979267.

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A pulse-width-modulator- (PWM-) based sliding mode controller is developed to study the effects of partial shade, temperature, and insolation on the performance of maximum power point tracking (MPPT) used in photovoltaic (PV) systems. Under partially shaded conditions and temperature, PV array characteristics become more complex, with multiple power-voltage maxima. MPPT is an automatic control technique to adjust power interfaces and deliver power for a diverse range of insolation values, temperatures, and partially shaded modules. The PV system is tested using two conventional algorithms: the Perturb and Observe (P&O) algorithm and the Incremental Conductance (IncCond) algorithm, which are simple to implement for a PV array. The proposed method applied a model to simulate the performance of the PV system for solar energy usage, which is compared to the conventional methods under nonuniform insolation improving the PV system utilization efficiency and allowing optimization of the system performance. The PWM-based sliding mode controller successfully overcomes the issues presented by nonuniform conditions and tracks the global MPP. In this paper, the PV system consists of a solar module under shade connected to a boost converter that is controlled by three different algorithms and is generated using Matlab/Simulink.

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Deniz, Matheus, Karolini Tenffen de Sousa, Isabelle Cordova Gomes, Marcos Martinez do Vale, and João Ricardo Dittrich. "Classification of environmental factors potentially motivating for dairy cows to access shade." Journal of Dairy Research 88, no. 3 (July 9, 2021): 274–77. http://dx.doi.org/10.1017/s0022029921000509.

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AbstractThe aim of this Research Communication was to apply the data mining technique to classify which environmental factors have the potential to motivate dairy cows to access natural shade. We defined two different areas at the silvopastoral system: shaded and sunny. Environmental factors and the frequency that dairy cows used each area were measured during four days, for 8 h each day. The shaded areas were the most used by dairy cows and presented the lowest mean values of all environmental factors. Solar radiation was the environmental factor with most potential to classify the dairy cow's decision to access shaded areas. Data mining is a machine learning technique with great potential to characterize the influence of the thermal environment in the cows' decision at the pasture.

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Cherukuri, Santhan Kumar, and Srinivasa Rao Rayapudi. "Enhanced Grey Wolf Optimizer based MPPT Algorithm of PV system under Partial Shaded Condition." International Journal of Renewable Energy Development 6, no. 3 (November 6, 2017): 203. http://dx.doi.org/10.14710/ijred.6.3.203-212.

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Partial shading condition is one of the adverse phenomena which effects the power output of photovoltaic (PV) systems due to inaccurate tracking of global maximum power point. Conventional Maximum Power Point Tracking (MPPT) techniques like Perturb and Observe, Incremental Conductance and Hill Climbing can track the maximum power point effectively under uniform shaded condition, but fails under partial shaded condition. An attractive solution under partial shaded condition is application of meta-heuristic algorithms to operate at global maximum power point. Hence in this paper, an Enhanced Grey Wolf Optimizer (EGWO) based maximum power point tracking algorithm is proposed to track the global maximum power point of PV system under partial shading condition. A Mathematical model of PV system is developed under partial shaded condition using single diode model and EGWO is applied to track global maximum power point. The proposed method is programmed in MATLAB environment and simulations are carried out on 4S and 2S2P PV configurations for dynamically changing shading patterns. The results of the proposed method are analyzed and compared with GWO and PSO algorithms. It is observed that proposed method is effective in tracking global maximum power point with more accuracy in less computation time compared to other methods.Article History: Received June 12nd 2017; Received in revised form August 13rd 2017; Accepted August 15th 2017; Available onlineHow to Cite This Article: Kumar, C.H.S and Rao, R.S. (2017 Enhanced Grey Wolf Optimizer Based MPPT Algorithm of PV System Under Partial Shaded Condition. Int. Journal of Renewable Energy Development, 6(3), 203-212.https://doi.org/10.14710/ijred.6.3.203-212

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Erol, Halil, and Mahmut Uçman. "Power optimization in partially shaded photovoltaic systems." Tehnički glasnik 12, no. 1 (March 27, 2018): 34–38. http://dx.doi.org/10.31803/tg-20180201165044.

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The Power-Voltage characteristic of a photovoltaic (PV) array exhibits non-linear behaviour when exposed to uniform solar irradiance. Maximum Power Point (MPP) tracking is challenging due to the varying climatic conditions in a solar PV system. Moreover, the tracking algorithm becomes more complicated due to the presence of multiple peaks in the power voltage characteristics under the condition of partial shading. This research is devoted to the Stochastic Beam Search (SBS) based algorithm and Stochastic Hill Climbing (SHC) for a maximum power point tracking (MPPT) at a partial shading condition in the PV system. To give a partial shading effect over the entire array of a PV system, a mast is placed in front of the modules. The modules in the array are connected in such a way that one does not need to rewire the electrical connection during the rearrangement of modules. It is validated that the power generation performance of an array under a moving shading condition is increased. Furthermore, it is observed that the SHC method outperforms the SBS method in the MMP tracking.

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Teo, J., Rodney Tan, V. Mok, Vigna Ramachandaramurthy, and ChiaKwang Tan. "Impact of Partial Shading on the P-V Characteristics and the Maximum Power of a Photovoltaic String." Energies 11, no. 7 (July 17, 2018): 1860. http://dx.doi.org/10.3390/en11071860.

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A photovoltaic system is highly susceptible to partial shading. Based on the functionality of a photovoltaic system that relies on solar irradiance to generate electrical power, it is tacitly assumed that the maximum power of a partially shaded photovoltaic system always decreases as the shading heaviness increases. However, the literature has reported that this might not be the case. The maximum power of a partially shaded photovoltaic system under a fixed configuration and partial shading pattern can be highly insusceptible to shading heaviness when a certain critical point is met. This paper presents an investigation of the impact of partial shading and the critical point that reduce the susceptibility of shading heaviness. Photovoltaic string formed by series-connected photovoltaic modules is used in this research. The investigation of the P-V characteristic curve under different numbers of shaded modules and shading heaviness suggests that the photovoltaic string becomes insusceptible to shading heaviness when the shaded modules irradiance reaches a certain critical point. The critical point can vary based on the number of the shaded modules. The formulated equation in this research contributes to determining the critical point for different photovoltaic string sizes and numbers of shaded modules in the photovoltaic string.

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Ollo, SIB, SORO Senan, and TRA BI Crolaud Sylvain. "Attacks and damage of termites (Insecta: Isoptera) in different cocoa agroforestry systems (Nawa, Côte d’Ivoire)." Journal of Animal & Plant Sciences 44.1 (April 30, 2020): 7567–76. http://dx.doi.org/10.35759/janmplsci.v44-1.3.

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To maintain its status of leading producer of cocoa in the world, Côte d'Ivoire must be contain the different types of threats, including the emergence of termites in cocoa farms. This study was conducted in the south-west of the country to evaluate the effect of cropping systems (full sun system, intermediate system and shaded system) on termite attacks. The study was conducted in four localities with different cocoa agroforestry systems. The sampling was made on cocoa trees in quadrats of 30mx30m and the attack rate was calculated. Eleven (11) termite species were identified. The wood-feeders groups were dominant. These termites were responsible for 41.82% of the damage on cocoa trees. Termite Attacks vary between different cropping systems. Full sun systems were most attacked comparing to intermediate shade systems that were least attacked by termites. This work shows that the shade system has an effect on termite attacks in cacao trees. The choice of right system can help to significantly reduce termite attacks in cocoa farms.

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Tiwari, Shubham. "Performance Analysis of 3kW Residential Grid-Connected Photovoltaic System with Microinverter Topology using System Advisor Model." International Journal for Research in Applied Science and Engineering Technology 9, no. 9 (September 30, 2021): 1294–97. http://dx.doi.org/10.22214/ijraset.2021.38176.

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Abstract: Grid connected rooftop PV systems are the most common form of solar energy utilization that helps home owners to reduce carbon footprint and save money in utility bills. This project focuses on the design and modelling of a 3KW residential PV system connected to a 240V single phase grid. The purpose of this study was to conduct an independent experiment on a photovoltaic system with microinverters, to determine their performance characteristics in shaded and unshaded conditions. The systems have fixed tilt angle and fixed azimuth angle. In order to analyse the performance of the systems, the Energy Yield, Performance Ratio, Capacity factor and Annual Energy have been used. This allowed to obtain reliable metrics even with different Irradiance values and different Peak Powers. In the conventional central inverters, several strings of PV modules are combined in order to achieve the power required from the inverter to operate. Strings are connected in parallel and then these strings are led to the inverter after running several meters of DC cables. These cables are often very thick and as a result are very expensive while at the same time, they add losses to the overall system. On the other hand, AC cables are much less expensive and they have fewer losses. A residential system was designed in SAM using specific weather data. The simulation results supported the fact that micro inverters perform well in both shaded and non-shaded conditions. A significant advantage of Micro Inverters is the avoidance of shading losses and mismatch among different PV technologies which consists a great challenge on PV installations. The String Inverter system produced an annual energy of 4763 kWh in the first year with no shading and 4286 kWh in the first year with shading losses. Keywords: Inverters, Photovoltaic cells, Photovoltaic systems, Solar energy, Solar panels.

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Tsafarakis, Odysseas, Kostas Sinapis, and Wilfried G. J. H. M. van Sark. "A Time-Series Data Analysis Methodology for Effective Monitoring of Partially Shaded Photovoltaic Systems." Energies 12, no. 9 (May 7, 2019): 1722. http://dx.doi.org/10.3390/en12091722.

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The majority of photovoltaic (PV) systems in the Netherlands are small scale, and installed on residential and commercial rooftops, where different objects in many cases may lead to the presence of shading and inevitable energy loss. Nevertheless, the energy loss due to expected shadow must be distinguished from the energy loss due to other malfunctions. In this study an algorithmic tool is presented that automates the process of analyzing monitoring data of partially shaded PV systems. The algorithm compares long-term and high-resolution yield data of a partially shaded PV system with the yield data of an unshaded PV system, as reference PV system, and automatically detects the energy loss due to the expected shadow, caused by any surrounding obstacles, and distinguishes it from any additional energy loss due to other malfunctions. This study focuses on PV systems with module-level power electronics (MLPE) since these are mostly used on PV systems on rooftops. Three different cases of shaded MLPE PV systems are presented to illustrate the versatility of the methodology. Furthermore, suggestions for further research are discussed at the end of the paper.

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BADOUD, Abd Essalam. "MPPT Controller for PV Array under Partially Shaded Condition." Algerian Journal of Renewable Energy and Sustainable Development 01, no. 01 (June 15, 2019): 99–111. http://dx.doi.org/10.46657/ajresd.2019.1.1.10.

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The output power of the Photovoltaic system having multiple arrays is reduced to a great extent when it is partially shaded due to environmental hindrances. Conventional popular MPPT methods are effective under uniform solar irradiance. However, under partially shaded conditions, these MPPTs can fail to track the real MPP because of the multiple local maxima which can be existed on PV characteristic curve under partially shaded condition. This paper reports the development of a maximum power-point tracking method for photovoltaic systems under partially shaded conditions using bond graph. The major advantages of the proposed method are simple computational steps, faster convergence, and its implementation on a low-cost microcontroller. The performance of proposed MPPT is analyzed according to the position of real MPP. Simulation results have been contrasted with real measured data from a commercial PV module of Photowatt PW1650.

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Mishima, Tomokazu, and Tokuo Ohnishi. "Power Compensation and Control System for Partially Shaded PV Array." IEEJ Transactions on Industry Applications 122, no. 8 (2002): 799–806. http://dx.doi.org/10.1541/ieejias.122.799.

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Smida, Mouna Ben, and Anis Sakly. "Fuzzy logic control of a hybrid renewable energy system: A comparative study." Wind Engineering 45, no. 4 (July 9, 2021): 793–806. http://dx.doi.org/10.1177/0309524x211028783.

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In this paper the authors have developed a hybrid renewable energy system. The studied structure comprises a wind energy generator, a shaded photovoltaic generator associated to an inertial storage system. The modeling of the global structure is developed and the control strategy is discussed. Conventional methods have been used to control the renewable sources. However, they may not have a suitable performance if the controlled system contains nonlinearity, as the wind turbine system or the shaded photovoltaic generator. In the presence of modeling uncertainties, the necessity of methods presenting controllers with appropriate performance as the advanced control strategies is inevitable. Fuzzy logic is used to control both the wind generator’s pitch angle and the maximum power point tracking (MPPT) of a shaded photovoltaic generator. The control of the storage flywheel, associated with the studied structure, to regulate the power supplied by renewable sources is also discussed. The design of the proposed strategy and its comparison with conventional controllers are carried out. The proposed method effectiveness is verified by MATLAB simulation results.

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Deng, Shijie, Alan P. Morrison, Yong Guo, Chuanxin Teng, Ming Chen, Yu Cheng, Houquan Liu, Xianming Xiong, and Libo Yuan. "Design of a Real-Time Breakdown Voltage and On-Chip Temperature Monitoring System for Single Photon Avalanche Diodes." Electronics 10, no. 1 (December 27, 2020): 25. http://dx.doi.org/10.3390/electronics10010025.

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The design and implementation of a real-time breakdown voltage and on-chip temperature monitoring system for single photon avalanche diodes (SPADs) is described in this work. In the system, an on-chip shaded (active area of the detector covered by a metal layer) SPAD is used to provide a dark count rate for the breakdown voltage and temperature calculation. A bias circuit was designed to provide a bias voltage scanning for the shaded SPAD. A microcontroller records the pulses from the anode of the shaded SPAD and calculates its real-time dark count rate. An algorithm was developed for the microcontroller to calculate the SPAD’s breakdown voltage and the on-chip temperature in real time. Experimental results show that the system is capable of measuring the SPAD’s breakdown voltage with a mismatch of less than 1.2%. Results also show that the system can provide real-time on-chip temperature monitoring for the range of −10 to 50 °C with errors of less than 1.7 °C. The system proposed can be used for the real-time SPAD’s breakdown voltage and temperature estimation for dual-SPADs or SPAD arrays chip where identical detectors are fabricated on the same chip and one or more dummy SPADs are shaded. With the breakdown voltage and the on-chip temperature monitoring, intelligent control logic can be developed to optimize the performance of the SPAD-based photon counting system by adjusting the parameters such as excess bias voltage and dead-time. This is particularly useful for SPAD photon counting systems used in complex working environments such as the applications in 3D LIDAR imaging for geodesy, geology, geomorphology, forestry, atmospheric physics and autonomous vehicles.

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Zhong, Qing, Nan Hua Yu, Kun Wang, Lin Feng, Guo Jie Li, and Kan Chen. "An Optimized MPP Tracking Algorithm under Partially Shaded Conditions in Photovoltaic System." Advanced Materials Research 860-863 (December 2013): 201–9. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.201.

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In photovoltaic (PV) power generation systems, the P-V curve of PV array contains several peaks under partially shaded condition (PSC) so that conventional MPP tracking (MPPT) methods can hardly find the real MPP (MPP). This paper proposes an optimized MPPT strategy, which is not only fit for PSC but also suitable for uniform shaded conditions (USC). Comparing the optimized MPPT strategies and conventional MPPT methods, this paper illustrates the improved performance of optimized strategy under PSC. The simulation and experiment results show that the optimized strategy can track the global MPP precisely to improve the efficiency of PV systems.

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He, Juanjuan, Jiao Fu, Jun Liu, and Jianhua Xiao. "A MPPT Algorithm Based on Membrane System for Photovoltaic Systems Under Partially Shaded Conditions." Journal of Computational and Theoretical Nanoscience 13, no. 6 (June 1, 2016): 3878–86. http://dx.doi.org/10.1166/jctn.2016.5222.

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Karatepe, Engin, Takashi Hiyama, Mutlu Boztepe, and Metin Çolak. "Voltage based power compensation system for photovoltaic generation system under partially shaded insolation conditions." Energy Conversion and Management 49, no. 8 (August 2008): 2307–16. http://dx.doi.org/10.1016/j.enconman.2008.01.012.

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Bhargavi, B., and P. Linga Reddy. "Improvement of Solar Energy System Under Partial Shading Conditions in Koneru Lakshmaiah Education Foundation." International Journal of Engineering & Technology 7, no. 1.8 (February 9, 2018): 197. http://dx.doi.org/10.14419/ijet.v7i1.8.16401.

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This paper consists of grid connected Solar photovoltaic (SPV) system. An output of SPV depends on the irradiation and temperature. Sometimes PV module is shaded due to nearby buildings, passing clouds etc. Power extracted from such partially shaded PV array is reduced. . The PV system at KLEF deemed to be university is considered. Total Harmonic Distortion (THD) and the output powers are computed using Matlab/Simulink using LC filter .These are compared with the actual values measured from the existing system . It is found that percentage of THD is reduced.

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Vieira Junior, Nilson Aparecido, Marcelo Augusto de Aguiar e. Silva, Paulo Henrique Caramori, Pablo Ricardo Nitsche, Karlmer Abel Bueno Corrêa, and Daniel Soares Alves. "Temperature, thermal comfort, and animal ingestion behavior in a silvopastoral system." Semina: Ciências Agrárias 40, no. 1 (February 15, 2019): 403. http://dx.doi.org/10.5433/1679-0359.2019v40n1p403.

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Thermal discomfort is one of the main causes of production losses in animals fully exposed to solar radiation under extensive livestock farming. The inclusion of trees in this farming system is the most efficient strategy to decrease the temperature and increase animal productivity without the need to explore new areas. In this context, the objective of this study was to characterize the microclimate in a silvopastoral system (SPS), a refuge area, and an open pasture, and evaluate thermal comfort and the ingestive behavior of animals under shade. The study was conducted at the Agronomic Institute of Paraná (IAPAR), located in Ibiporã, Paraná state, Brazil, in three areas with distinct management systems: a SPS of Eucalyptus grandis with Tifton 85 (Cynodon spp.), a woodland of Leucena leucocephala that provided shade to cattle, and a pasture in full sun (PFS). Automatic meteorological stations were installed in the SPS (one station beside the tree lines and the other in an average distance perpendicular to the rows), one in the refuge area, and one in the PFS. The measured variables were air temperature and relative humidity. The mean temperatures of the shaded treatments were compared to those of the PFS using a t-test. The mean values of the temperature and humidity index (THI) were calculated for each season of the year. The animal ingestion behavior in the SPS was analyzed in three typical days in different seasons of the year. Significant differences were observed between shade treatments and full-sun pasture, with a temperature decrease ranging from 0.4 to 1.6 °C in the shaded systems. The comparison of animal thermal comfort between the study areas in different seasons of the year indicated that there were no significant differences in thermal comfort between the SPS and refuge area relative to the PFS, suggesting a need to monitor the animals’ body temperature to better estimate thermal comfort. The evaluation of the ingestive behavior evidenced the animals’ preference to perform activities under tree shade and that the SPS led to changes in their food habits, optimizing grazing time. Therefore, the trees directly affected the microclimate of the studied environments, attenuating the temperature, protecting the animals against direct solar radiation, and providing better thermal comfort.

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N. M. Alahmadi, A., and Hegazy Rezk. "A Robust Single-Sensor MPPT Strategy for Shaded Photovoltaic-Battery System." Computer Systems Science and Engineering 37, no. 1 (2021): 63–71. http://dx.doi.org/10.32604/csse.2021.015029.

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Ding, Min, Yi Tang, Weihua Cao, Zhili Tan, Qingyi Wang, and Danyun Li. "Sliding Mode MPPT Controller for Photovoltaic Systems Under Partial Shading Conditions." Journal of Advanced Computational Intelligence and Intelligent Informatics 20, no. 7 (December 20, 2016): 1112–18. http://dx.doi.org/10.20965/jaciii.2016.p1112.

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This study focuses on maximum power point tracking (MPPT) control for photovoltaic (PV) power generation systems under partial shading conditions. A mathematic model of the partially shaded solar cell is built. Then, the output characteristics of the partial-shade array are analyzed. Based on the model of the PV battery and the concept of the average-state switch cycle, an average-state mathematical model of the PV power generation system using a boost circuit for the realization circuit is established. A sliding mode controller based on the integral sliding mode function is designed to realize MPPT in the PV power generation system. Finally, simulations in MATLAB/Simulink confirm the functionality and performance of the proposed controller.

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Jain, Lokesh Kumar. "Simulation and Design of Artificial Intelligence Based MPPT System for Partial Shaded Solar Photovoltaic System." International Journal for Research in Applied Science and Engineering Technology 7, no. 12 (December 31, 2019): 125–30. http://dx.doi.org/10.22214/ijraset.2019.12021.

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Irani, Pourang, Dean Slonowsky, and Peer Shajahan. "Human Perception of Structure in Shaded Space-Filling Visualizations." Information Visualization 5, no. 1 (March 2006): 47–61. http://dx.doi.org/10.1057/palgrave.ivs.9500113.

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Very early in the object recognition process the human visual system extracts shading information. While shading can enhance the visibility of structures, it can have a negative impact on the judgment of sizes of elements in a structure. In certain visualization systems the underlying hierarchical structure is not noticeably explicit, such as in space-filling techniques. We hypothesize that in such cases, shading can make the structure more explicit. In this paper, we report the results of two experiments designed to investigate the effects of shading information on extracting the structure in space-filling visualizations. In the first experiment subjects performed better with the visualization tool with shading on structure-based tasks. Our results do not show that shading impairs users' judgment on size-based tasks. A subjective evaluation shows that users preferred interacting with the system when shading was available. The second experiment was designed to investigate further users' capacity to identify structural elements within the space-filling visualization. A substructure recognition task was employed in this experiment and results show that users are capable of identifying sub-structures quicker and with fewer errors when the visualization tool was equipped with shading information than without. The results of both experiments provide evidence that shading information can be used to effectively obtain structural information from spacefilling visualizations.

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Amin, Hajizadeh, and Warrier Anil Kumar Jishnu. "Parameter Identification and Effect of Partial Shading on a Photovoltaic System." E3S Web of Conferences 64 (2018): 06006. http://dx.doi.org/10.1051/e3sconf/20186406006.

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Partial shading cause significant losses to the performance of a photovoltaic (PV) system. So, it is imperative to study effects of partial shading; for that a two-diode model of the experimental setup made. Upon verifying the model with the experimental parameters, a MATLAB/Simulink model is made based on this model. Various shading patterns, the effect of bypass diodes; the effect of overlapping bypass diode is studied on this MATLAB/Simulink model. It is found out that the reduction in power loss is depended on the location of the shaded cell but not the area of the shaded cell. Also, the over-lapping bypass diode configuration has a slight improvement in the PV performance compared to the non-overlapping bypass diode configuration. An experimental test is also conducted by applying different shading pattern and they proves the results are compatible with the simulated results.

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Seemann, Marcus D., Martin Heuschmid, Joachim Vollmar, Axel Küttner, Wolfgang Schöber, Jürgen F. Schäfer, Michael Bitzer, and Claus D. Claussen. "Virtual Bronchoscopy: Comparison of Different Surface Rendering Models." Technology in Cancer Research & Treatment 2, no. 3 (June 2003): 273–79. http://dx.doi.org/10.1177/153303460300200310.

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The aim of this study was to compare different representation models of surface-rendered virtual bronchoscopy. 10 consecutive patients with inoperable primary lung tumors underwent thin-section spiral computed tomography. The structures of interest, the tracheobronchial system and anatomical and pathological thoracic structures were segmented using an interactive threshold interval volume-growing segmentation algorithm and visualized with the aid of a color-coded surface rendering method. For virtual bronchoscopy, the tracheobronchial system was visualized using a triangle-surface rendering model, a shaded-surface rendering model and a transparent shaded-surface rendering model. The triangle-surface rendering model allowed optimum detailed spatial representation of the dimensions of extraluminal anatomical and pathological mediastinal structures. As the lumen of the tracheobronchial system was less well defined, the rendering model was of limited use for depiction of the airway surface. The shaded-surface rendering model facilitated an optimum assessment of the airway surface, but the mediastinal structures could not be depicted. The transparent shaded-surface rendering model provides simultaneous adequate to optimum visualization and assessment of the intraluminal airway surface and the extraluminal mediastinal structures as well as a quantitative assessment of the spatial relationship between these structures. Fast data acquisition with a multi-slice detector spiral computed tomography scanner and the use of virtual bronchoscopy with the transparent shaded-surface rendering model obviate the need for time consuming detailed analysis and presentation of axial source images by providing improved the diagnostic imaging of endotracheal and endobronchial diseases and offering a useful alternative to fiberoptic bronchoscopy.

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A. P., Yoganandini, and Anitha G. S. "A modified particle swarm optimization algorithm to enhance MPPT in the PV array." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 5 (October 1, 2020): 5001. http://dx.doi.org/10.11591/ijece.v10i5.pp5001-5008.

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Due to the growing demand for electrical power, the researchers are trying to fulfill this demand by considering different ways of renewable energy resource as existing energy resources failed to do so. The solar energy from the sun is freely available, and by using photovoltaic (PV) cell power can be generated. However, it depends on rays fall on the PV cell, climatic condition. Thus, to enhance the efficiency of the photovoltaic (PV) systems, maximum power point tracking (MPPT) of the solar arrays is needed.The output of solar arrays mainly depends on solar irradiance and temperature. The mismatch phenomenon takes place due to partial shade, and it causes to the power output, which brings the incorrect operation of traditional MPP tracker. In this shaded condition, PV array exhibits multiple extreme points. In general, under this scenario, the MPPT approaches fail to judge the MPP, and it leads to low efficiency. The conventional approaches of PSO based algorithms can able to track the MPP under shading condition. However, the optimization process leads to issues in tracking speed. Thus, there a need for an efficient MPPT system which can track MPPT effectively in shaded condition? Hence, the proposed manuscript presents a modified Particle Swarm Optimization (PSO) algorithm is introduced to enhance the tracking speed as well as performance. The outcomes of the proposed system are compared with the traditional PSO system and are found that the tracking speed of MPP, accuracy, and efficiency is improved.

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Choi, Jung-Sik, and Dong-Hwa Chung. "A Novel MPPT Control of PV MIC System Considering the Shaded Effect." Journal of the Korean Institute of Illuminating and Electrical Installation Engineers 26, no. 5 (May 31, 2012): 21–33. http://dx.doi.org/10.5207/jieie.2012.26.5.021.

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Prasad, Revuru, and Rathinam Thiyagarajan. "Kinetic Gas Molecular Optimization Method for PV System Under Partial Shaded Condition." International Journal of Intelligent Engineering and Systems 13, no. 4 (August 31, 2020): 33–43. http://dx.doi.org/10.22266/ijies2020.0831.04.

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Chauhan, Urvashi, Vijander Singh, Bhavnesh Kumar, and Asha Rani. "An improved MVO assisted global MPPT algorithm for partially shaded PV system." Journal of Intelligent & Fuzzy Systems 38, no. 5 (May 29, 2020): 6715–26. http://dx.doi.org/10.3233/jifs-179749.

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Rosenberg, David E., and Travis P. Marcotte. "Land-use system modeling and analysis of shaded cacao production in Belize." Agroforestry Systems 64, no. 2 (August 2005): 117–29. http://dx.doi.org/10.1007/s10457-004-0535-9.

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Mishima, Tomokazu, and Tokuo Ohnishi. "A power compensation and control system for a partially shaded PV array." Electrical Engineering in Japan 146, no. 3 (2003): 74–82. http://dx.doi.org/10.1002/eej.10203.

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Roba, Alemayehu Diriba, Shimelis Dekeba, Wasihun Gizaw, and Mosisa Mezigebu. "EVALUATION OF COFFEE GROWTH, YIELD AND QUALITY UNDER COFFEE SHADE TREES AT MECHARA ON STATION, WEST HARARGHE ZONE, ETHIOPIA." International Journal of Research -GRANTHAALAYAH 9, no. 4 (April 30, 2021): 84–104. http://dx.doi.org/10.29121/granthaalayah.v9.i4.2021.3816.

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Abstract: Coffee production with shade trees is important to improve growth and quality of coffee, sustain and restore agroecology and nature based agroforestry practices. The trial was conducted at Mechara Agricultural Research Center (on station) in DaroLebu District of West Hararghe Zone, Oromia, Ethiopia. The study was intended to evaluate the influence of coffee shade trees on growth performance, yield and quality of coffee (Coffea arabica L.) under the canopy of Erytherina absinica, Cordia africana and Acacia sieberiana. The design was Randomized complete block design with three replications. The outcome had been observed a significant value at (p<0.05) probability level, non- significant value at (p>0.05) probability level and highly significance value at (p<0.01) probability level between treatments. Statistically significant and non- significant differences were observed between shaded and unshaded as well as within shaded effect based on the given parameters. Integration of shade in coffee farming system created creditable promising in producing organic coffee. Shade utility could be confirmed as to be ecologically sustainable, economically viable and socially acceptable practice. In so doing that, the effect of Erytherina absinica, Cordia africana shade trees illustrated the highest mean value in most parameters, while the least one is under the Acacia sieberiana shade tree. So the effect of Erytherina absinica mean observed with the highest value on total bearing plants 60%, thousand seed weight 59% and yield in Quintal per hectare 47.4% greater than the least treatments’ mean value based on growth parameters. On the other hand, the effect of Erytherina absinica mean observed with the higher value on aromatic intensity 46.4%, aromatic quality 87.2%, acidity 92.4%, body 93.5%, flavors 88.6% and overall quality 88.6% than the least treatments’ mean value, and also the effect of un-shade mean observed with the higher value on astringency 68.8% and bitterness 93.5% than the least treatments’ mean value based on organoleptic parameters. The highest mean value of Erytherina absinica observed on total bearing plants 12.1, thousand seed weight 130 gram and yield in Quintal per hectare 5.7 based on growth parameters, while based on organoleptic parameters, the highest mean value observed under the effect of Erytherina absinica shade tree on aromatic intensity 4.5, aromatic quality 3.9, acidity 7.9, body 7.7, flavors 7.9 and overall quality 7.9. Therefore, based on the most treatments’ parameters, to be the best shade tree was Erythrina abyssinica followed by cordia africana. Commonly, the dynamic indication of the treatment’s means difference were indicated between shaded and unshaded rather than within shaded means variation at most treatments’ parameters.

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Helyes, L., A. Lugasi, and Z. Pék. "Effect of natural light on surface temperature and lycopene content of vine ripened tomato fruit." Canadian Journal of Plant Science 87, no. 4 (October 1, 2007): 927–29. http://dx.doi.org/10.4141/cjps07022.

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Indeterminate round type tomato (Lycopersicon esculentum Mill.) grown on a supporting trellace system in the field was used to determine the correlation between light exposure and the surface temperature and lycopene content of tomato fruit. The positive correlation between solar radiation and surface temperature was stronger (R2 = 0.87) on non-shaded (NS) than on shaded (SF) (R2 >= 0.79) tomato fruits. There was strong negative correlation (R2 = 0.95) between surface temperature and lycopene content of tomato fruits. Increasing solar radiation and temperature explained the lower content of lycopene content and therefore the loss of nutritional quality of the non-shaded tomato fruits. Key words: Tomato, fruit surface temperature, lycopene

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Rothley, K. D., and G. Dutton. "Behavioral responses to environmental change alter direct and indirect trait-mediated interactions." Canadian Journal of Zoology 84, no. 7 (July 1, 2006): 1053–58. http://dx.doi.org/10.1139/z06-076.

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We used a field-based experiment to explore the consequences of altered environmental conditions on a predator–prey–resource system. The foraging choices of grasshoppers on plant resources were measured in the presence and absence of predator spiders and in shaded and unshaded conditions. We show that shading conditions affected the spiders, their direct behavioral interactions with the grasshoppers, and the indirect behaviorally mediated interactions between the spiders and the plants. In unshaded conditions in response to spiders, grasshoppers reduced their energy intake by 90%, reduced their time spent feeding by 68%, and switched to a largely grass diet that should increase mortality, while in shaded conditions spiders induced no behavioral shift. In no shade, spiders had an indirect positive effect on forb plants as evidenced by a trophic cascade pattern in plant biomass in the one-, two-, and three-trophic-level communities. But in shade, there was no indirect interaction of the spiders on the plants. Our results demonstrate the challenge of predicting the effects of environmental change on complex, real-world ecosystems and highlight the critical need for conducting experimental manipulations in the proper context with full complements of species.

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Pathy, Subramani, Sridhar, Thamizh Thentral, and Padmanaban. "Nature-Inspired MPPT Algorithms for Partially Shaded PV Systems: A Comparative Study." Energies 12, no. 8 (April 16, 2019): 1451. http://dx.doi.org/10.3390/en12081451.

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PV generating sources are one of the most promising power generation systems in today’s power scenario. The inherent potential barrier that PV possesses with respect to irradiation and temperature is its nonlinear power output characteristics. An intelligent power tracking scheme, e.g., maximum power point tracking (MPPT), is mandatorily employed to increase the power delivery of a PV system. The MPPT schemes experiences severe setbacks when the PV is even shaded partially as PV exhibits multiple power peaks. Therefore, the search mechanism gets deceived and gets stuck with the local maxima. Hence, a rational search mechanism should be developed, which will find the global maxima for a partially shaded PV. The conventional techniques like fractional open circuit voltage (FOCV), hill climbing (HC) method, perturb and observe (P&O), etc., even in their modified versions, are not competent enough to track the global MPP (GMPP). Nature-inspired and bio-inspired MPPT techniques have been proposed by the researchers to optimize the power output of a PV system during partially shaded conditions (PSCs). This paper reviews, compares, and analyzes them. This article renders firsthand information to those in the field of research, who seek interest in the performance enhancement of PV system during inhomogeneous irradiation. Each algorithm has its own advantages and disadvantages in terms of convergence speed, coding complexity, hardware compatibility, stability, etc. Overall, the authors have presented the logic of each global search MPPT algorithms and its comparisons, and also have reviewed the performance enhancement of these techniques when these algorithms are hybridized.

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Jeong, Jae-Hoon, and Kiwon Park. "Numerical Analysis of 2-D Positioned, Indoor, Fuzzy-Logic, Autonomous Navigation System Based on Chromaticity and Frequency-Component Analysis of LED Light." Sensors 21, no. 13 (June 25, 2021): 4345. http://dx.doi.org/10.3390/s21134345.

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Topics concerning autonomous navigation, especially those related to positioning systems, have recently attracted increased research attention. The commonly available global positioning system (GPS) is unable to determine the positions of vehicles in GPS-shaded regions. To address this concern, this paper presents a fuzzy-logic system capable of determining the position of a moving robot in a GPS-shaded indoor environment by analyzing the chromaticity and frequency-component ratio of LED lights installed under the ceiling. The proposed system’s performance was analyzed by performing a MATLAB simulation of an indoor environment with obstacles. During the simulation, the mobile robot utilized a fuzzy autonomous navigation system with behavioral rules to approach targets successfully in a variety of indoor environments without colliding with obstacles. The robot utilized the x and y coordinates of the fuzzy positioning system. The results obtained in this study confirm the suitability of the proposed method for use in applications involving autonomous navigation of vehicles in areas with poor GPS-signal reception, such as in tunnels.

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Li, Nian Xuan, and Yue Feng Wang. "Visual Simulation for Satellite on Track and Shaded Part Compute for Solar Panel." Applied Mechanics and Materials 190-191 (July 2012): 758–62. http://dx.doi.org/10.4028/www.scientific.net/amm.190-191.758.

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Abstract: For the purpose of scene simulation of satellite moving on track and shaded part compute for solar panel, this paper analyzed the visualization system's software architecture, introduced Program design method with GDI+ and OpenGL on MFC frame. Based on the analysis, software architecture was optimized and some reusable classes were also designed. Therefore a more reusable, extendable and modularized visualization system can be realized. It covered a wide range of function such as the visual simulation, shaded part compute for solar panel and results display. The results showed that this visualization system was satisfactory and feasible in the simulation.

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Ibrahim, Abdalla Eltigani, Nursyarizal Mohd Nor, Illani Binti Mohd Nawi, Mohd Fakhizan R, and Khairul Nisak Mohd. "Genetic algorithm to improve power output of photovoltaic system under partial shaded condition." International Journal of Power Electronics and Drive Systems (IJPEDS) 10, no. 4 (December 1, 2019): 2182. http://dx.doi.org/10.11591/ijpeds.v10.i4.pp2182-2189.

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The Partial Shaded Condition (PSC) is a process of non-optimal power capture in photovoltaic (PV) system; it will happen when one or all the PV solar cells get shaded by external factors. This phenomenon makes a sudden change in cell irradiance and lead to non-optimal power capture and reduces the generated power in PV systems. Cell under PSC generates one global peak (GP) and many local peaks (LPs), but the tracking of GP under (PSCs) effectively are still a big challenge to the researchers. In this paper, Fuzzy Logic Control (FLC) and optimized FLC algorithms were developed to track the PV power during the PSCs. The configuration of both algorithms are designed, simulated and evaluated using MATLAB/Simulink and their performance was compared with other literature techniques to study their capability to track the MPPT under PSCs. Proposed GA-FLC achieved 0.7 S as tracking time to find and track the Global Peak of Maximum power Point (GMPP) under PSCs and the usage of buck/boost converter in this technique achieved 98.5% of tracking accuracy. GA-FLC shows good dynamic performance in terms of tracking accuracy and complexity under PSCs compared to other techniques.

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O'Toole, Alice J. "Structure from Stereo by Associative Learning of the Constraints." Perception 18, no. 6 (December 1989): 767–82. http://dx.doi.org/10.1068/p180767.

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A computational model of structure from stereo that develops smoothness constraints naturally by associative learning of a large number of example mappings from disparity data to surface depth data is proposed. Banks of disparity-selective graded response units at all spatial locations in the visual field were the input data. These cells responded to matches of luminance change at convergent, divergent, or zero offsets in the left and right ‘retina’ samples. Surfaces were created by means of a pseudo-Markov process. From these surfaces, shaded marked and ummarked surfaces were created, along with random-dot versions of the same surfaces. Learning of these example shaded and shaded marked surfaces allowed the system to solve stereo mappings both for the surfaces it had learned and for surfaces it had not learned but which had been created by the same pseudo-Markov process. Further, the model was able to solve some random-dot versions of the surfaces when the surfaces had been learned as shaded marked surfaces.

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Anderson, Wendy B., and William G. Eickmeier. "Physiological and morphological responses to shade and nutrient additions of Claytonia virginica (Portulacaceae): implications for the "vernal dam" hypothesis." Canadian Journal of Botany 76, no. 8 (August 1, 1998): 1340–49. http://dx.doi.org/10.1139/b98-134.

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Because of their unique phenology and physiology, spring ephemeral herbs are believed to play an important role in intrasystem nutrient cycling in deciduous forest ecosystems. It was hypothesized that they function as a "vernal dam" by temporarily sequestering nutrients and preventing leaching from the system during a period of high nutrient availability. However, spring ephemerals require high-irradiance growing conditions. How do their physiological and morphological responses to ambient light and shade limit their ability to sequester excess nutrients? We performed field experiments using Claytonia virginica L. as a model to test several responses to shade and increasing levels of nutrient additions. We also examined the biomass responses and nutrient storage capacities of other spring ephemeral herbs. In C. virginica, shading reduced ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco) activity, photosynthesis rate, specific leaf weight, leaf width/length (W/L), and biomass; nutrient additions increased W/L and biomass only under unshaded conditions. Other herbs responded similarly but reached maximum biomass at lower nutrient addition levels than C. virginica. Shading reduced and nutrient additions increased nitrogen and phosphorus concentrations in both C. virginica and other herbs. Shaded herbs generally reached nutrient saturation at lower nutrient addition levels than unshaded herbs. Overall, unshaded plants sequestered larger amounts of nutrients than shaded plants. This pattern is best explained by a reduction in biomass under shaded conditions. We concluded that C. virginica and other spring herbs, although important components in forest nutrient cycling in the early spring, are limited in their capacity to store excess nutrients, particularly when shaded.Key words: Claytonia virginica, nutrient cycling, spring ephemerals, vernal dam.

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Journal articles on the topic 'Shaded system'

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