نتایج جستجو برای: trees quality reduction
تعداد نتایج: 1292214 فیلتر نتایج به سال:
a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...
Trees can improve air quality, but at the same time, pollution might put them at risk. Plane(Platanus orientalis L) and willow trees (Salix babylonicaL) are important trees in the green space of Tehran. Plane trees in Tehran have experienced early autumn in recent years due to severe air pollution. The present study, investigated some physiological traits of these trees under study to determine...
the speech enhancement techniques are often employed to improve the quality and intelligibility of the noisy speech signals. this paper discusses a novel technique for speech enhancement which is based on singular value decomposition. this implementation utilizes a genetic algorithm based optimization method for reducing the effects of environmental noises from the singular vectors as well as t...
Bracket fungi are the most important macroscopic fungi in the forest as trees are parasitic and saprophytic . This aim of this study is investigation on relate of between some of the characteristics of host and frequency of bracket fungi in district one of Shastkolate forest of Gorgan . Inventory of trees infected by bracket fungi was done using two strip transects and Factors , including the...
Quercus brantii Lindl. and Pistacia atlantica Desf. are the most important tree species in Zagros forests, The abundant use of these trees by the inhabitants of the area has led to a reduction in the quality and quantity of these valuable species, as well as the creation of heterogeneous masses.Recognizing the spatial pattern and the interactions of trees can be a key to managerial interve...
Urban shade trees offer significant benefits in reducing building air-conditioning demand and improving urban air quality by reducing smog. The savings associated with these benefits vary by climate region and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree-planting programs can be designed to have lower costs so that they off...
the establishment and survival of seedlings is one of the main objectives of forest management which ensures continues production. the aim of this article is the investigation of dead trees effect on beech and hornbeam seedlings in masal's forests. for this reason, 30 dead trees were selected, and the control trees were selected in four aspects around the dead trees. they were the same as ...
one of the indicators of management and sustainability control of forest resources is the definition deforestation and degradation types. these factors hazard quantitative and qualitative of the iranian forests. in this study with integrated approach, different forms of forest degradation identified in the forest areas with a reviews of library resources and then investigation the degree of sta...
the purpose of this research was to assess the influence of several orchard systems involving trees trained to different leader numbers on growth, cropping, and fruit quality of two apple cultivars. the study was conducted during 1994-2007 at the fruit experimental station in samotwór, next to wrocław (south-western poland). one-year-old trees of ‘elstar’ and ‘jonagold’ cultivars on the m.9 roo...
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