نتایج جستجو برای: ماهوارههای leo
تعداد نتایج: 5609 فیلتر نتایج به سال:
In this paper, we discuss on two important issues through the realization of global personal communication networks with low earth orbital (LEO) satellites. The first issue is the selection of an effective multiple access scheme which can utilize the limited spectrum allocated to these systems. In this way, we focus on the schemes based on spread spectrum techniques and explain their unique cha...
Development of the past decade have confirmed that ATM technology has the potential of becoming the transport mechanism in many multimedia networks where high-speed traffic and Quality of Service guarantees must be provided. More recently, we have witnessed a surge of interest in Low Earth Orbiting (LEO) satellite networks with on-board ATM switches, which hold the promise of offering an econom...
Phishing website creators and anti-phishing defenders are in an arms race. Cloning a website is fairly easy and can be automated by any junior programmer. Attempting to recognize numerous phishing links posted in the wild e.g. on social media sites or in email is a constant game of escalation. Automated phishing website detection systems need both speed and accuracy to win. We present a new met...
This study was carried out to evaluate the antibacterial activity of aqueous and organic extracts of Thymus capitatus L. (Lamiaceae) leaves and stems. Dried ground powder leaves and stems were extracted with water (aqueous extracts), ethanol, dichloromethane and hexane (Soxhlet extracts). The antibacterial activity of these extracts was evaluated against bacteria using disc diffusion method. Th...
In the near future low earth orbit (LEO) satellite communication networks will partially substitute for fixed terrestrial multimedia networks especially in sparsely populated areas. Unlike fixed terrestrial networks, ongoing calls may be dropped if satellite channels are shadowed. Therefore, in most LEO satellite communication networks more than one satellite need to be simultaneously visible i...
A sparse nucleation process on sapphire ~0001! substrates has been developed for the growth of GaN thin films. The density of nucleation sites is reduced to only 4310 cm. Based on this process, we performed direct lateral epitaxial overgrowth ~LEO! of GaN by metalorganic chemical vapor deposition on patterned SiO2/sapphire ~0001! substrates. An aggregate lateral to vertical growth rate ratio of...
We present a wide-field (4.5 deg2) photometric and spectroscopic survey of the Leo I dwarf spheroidal (dSph) galaxy to explore its extended morphology and dynamics. As in previous papers in this series, we take advantage of photometry in the M, T2, and DDO51 filter system to select Leo I red giant branch star candidates, and, so far, this selection technique has proven 100% reliable in selectin...
With the rise of a new generation low Earth orbit (LEO) satellite constellations and advancement 6G network, satellite–terrestrial integrated Internet Things (IoT) in future will achieve global coverage through integration LEO constellation, extend computing to edge network deployment services constellation so as meet demand mass connection latency data processing. The be an cloud combining com...
در این مقاله پارامترهای مؤثر بر زمان رؤیت ماهواره در مدارهای کم ارتفاع مرور شده و میزان تأثیر هریک از آنها بررسی شده است. سپس بیشترین میزان دسترسی به ماهواره ای کم ارتفاع در ارتفاعهای مختلف توسط کاربران زمینی در عرضهای جغرافیایی مختلف برای زاویه دید ثابت، محاسبه شده است. برای این منظور، پارامتر زاویه شیب مداری ماهواره مورد توجه قرار گرفته است. این دسترسی با تفکیک به دو دیدگاه تعداد دفعات رؤیت و...
Castro et al. (1996) have concluded that μ Leo has three times the solar metallicity. That conclusion is based on their own work and on rezeroed values of [Fe/H] from the literature. A review of their paper reveals that there are significant omissions from their list of literature results. In addition, their procedure for establishing zero points for values of [Fe/H] is found to be fallacious. ...
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