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  2. Two-ray ground-reflection model - Wikipedia

    en.wikipedia.org/.../Two-ray_ground-reflection_model

    From the figure the received line of sight component may be written as = {() /}and the ground reflected component may be written as = {() (+ ′) / + ′}where () is the transmitted signal, is the length of the direct line-of-sight (LOS) ray, + ′ is the length of the ground-reflected ray, is the combined antenna gain along the LOS path, is the combined antenna gain along the ground-reflected ...

  3. Signal strength in telecommunications - Wikipedia

    en.wikipedia.org/wiki/Signal_strength_in...

    High-powered transmissions, such as those used in broadcasting, are expressed in dB-millivolts per metre (dBmV/m). For very low-power systems, such as mobile phones, signal strength is usually expressed in dB-microvolts per metre (dBμV/m) or in decibels above a reference level of one milliwatt .

  4. Effective radiated power - Wikipedia

    en.wikipedia.org/wiki/Effective_radiated_power

    The ideal dipole antenna could be further replaced by an isotropic radiator (a purely mathematical device which cannot exist in the real world), and the receiver cannot know the difference so long as the input power is increased by 2.15 dB. The distinction between dB d and dB i is often left unstated and the reader is sometimes forced to infer ...

  5. Gain (antenna) - Wikipedia

    en.wikipedia.org/wiki/Gain_(antenna)

    When an antenna's maximum gain is specified in decibels (for instance, by a manufacturer) one must be certain as to whether this means the gain relative to an isotropic radiator or with respect to a dipole. If it specifies dBi or dBd then there is no ambiguity, but if only dB is specified then the fine print must be consulted.

  6. Comparison of database administration tools - Wikipedia

    en.wikipedia.org/wiki/Comparison_of_database...

    Browser based - executes on a computer server and is accessed via a network using a web browser; desktop - executes on a personal computer; Create/alter table: Yes - can create table, alter its definition and data, and add new rows; Some - can only create/alter table definition, not data; Browse table: Yes - can browse table definition and data

  7. Mobile phone signal - Wikipedia

    en.wikipedia.org/wiki/Mobile_phone_signal

    Since cell phones rely on radio waves, which travel through the air and are easily attenuated (particularly at higher frequencies), mobile phones may be unreliable at times. Like other radio transmissions, mobile phone calls can be interrupted by large buildings , terrain, trees, or other objects between the phone and the nearest base.

  8. Cell-based models - Wikipedia

    en.wikipedia.org/wiki/Cell-based_models

    Cell-based models are mathematical models that represent biological cells as discrete entities. Within the field of computational biology they are often simply called agent-based models [1] of which they are a specific application and they are used for simulating the biomechanics of multicellular structures such as tissues. to study the influence of these behaviors on how tissues are organised ...

  9. Cellular model - Wikipedia

    en.wikipedia.org/wiki/Cellular_model

    A cellular model is a mathematical model of aspects of a biological cell, for the purposes of in silico research. Developing such models has been a task of systems biology and mathematical biology .