Wireless Communications Wi-Fi, Bluetooth, and Zigbee essays

Wireless Communications Wi-Fi, Bluetooth, and Zigbee essays There are a number of wireless technologies in use for low- to high- bit-rate transmissions in residential, light commercial, commercial, and industrial applications. These include Wi-Fi, Bluetooth, and Zigbee. While many experts are predicting that one standard will outdo the other, this paper describes the benefits of these technologies and explains the unique position each has in the wireless spectrum. Wireless fidelity (Wi-Fi) is a high-frequency wireless local area network (TechTarget). The Wi-Fi technology is rapidly gaining acceptance in many companies as an alternative to a wired LAN and can also be installed for a home network. Wi-Fi is specified in the IEEE 802.11b specification and is part of a series of wireless specifications together with 802.11, 802.11a, and 802.11g. All four standards use the Ethernet protocol and carrier sense multiple access with collision avoidance for path sharing. Wi-Fi technology operates in the 2.4 GHz range offering data speeds up to 11 megabits per second. The modulation method selected for 802.11b is known as complementary code keying, which allows higher data speeds and is less susceptible to multipath-propagation interference than successors. Bluetooth is a specification that describes how devices such as mobile phones, computers, and personal digital assistants can be interconnected using a short-range wireless connection (TechTarget). Bluetooth requires that a low-cost transceiver chip be included in each device which transmits and receives in a band of 2.45 GHz that is available globally. In addition to data, up to three voice channels are available. Each device has a unique 48-bit address from the IEEE 802 standard. Connections can be point-to- point or multipoint. The maximum range is 10 meters. Data can be exchanged at a rate of 1 megabits per second. A frequency hop scheme allows devices to communicate in areas wi...

Coyote Facts (Canis latrans)

Coyote Facts (Canis latrans) The coyote (Canis latrans) is a medium-sized canid that is closely related to the dog and the wolf. The animal is well-known for its yips, howls, and other vocalizations. In fact, the scientific name for the coyote means barking dog. The common name comes from the Nahatl word coyÃ… tl. Fast Facts: Coyote Scientific Name: Canis latransCommon Names: Coyote, prairie wolfBasic Animal Group: MammalSize: 32 to 37 inches plus 16 inch tailWeight: 20 to 50 poundsLifespan: 10 yearsDiet: OmnivoreHabitat: North and Central AmericaPopulation: MillionsConservation Status: Least Concern Description Coyotes are larger than foxes and slightly smaller than wolves. The average adult ranges from 32 to 36 inches in length (head and body) with a 16 inch tail and weight between 20 and 50 pounds. Size varies depending on habitat, but females tend to be shorter in height and length than males. Coyote fur color ranges from reddish to grayish brown, depending on the animals habitat. Melanistic (black) forms occur, but white or albino coyotes are extremely rare. The animal has white neck and belly fur and a black-tipped tail. The face features a long muzzle and pointed ears, and the tail is brush-shaped like that of a fox. While coyotes and wolves are of comparable size and coloration, coyote ears are more sharply upright, their face and frame are leaner, and they run with their tail held low. In contrast, a wolf runs with its tail held horizontally. Habitat and Distribution The coyotes range originally spanned from the plains and deserts of western North America through Mexico and into Central America. The extirpation of wolves in North America allowed expansion across the United States and much of Canada. Currently, coyotes are found from Panama in the south up to Alaska in the north. While suited to prairies and deserts, the species has adapted to nearly every habitat, including urban environments. Diet and Behavior Coyotes, like other canines, are omnivorous. They hunt rabbits, snakes, frogs (not toads), deer and other ungulates, and turkeys and other large birds. While they prefer their natural prey, they will take chickens, lambs, calves, and pets. In addition, coyotes eat carrion, insects, grass, and fruit. With their excellent senses of hearing and smell, coyotes can detect prey at a distance. Then, they track prey by sight. For smaller prey, coyotes are solitary hunters. However, they will form packs to cooperatively hunt deer, elk, sheep, and pronghorns. Coyotes are not as social as wolves, but they will act cooperatively to hunt and raise offspring. Perry McKenna Photography / Getty Images Reproduction and Offspring Coyotes are monogamous. Mating occurs between February and April. The pair seeks or builds a den for birthing and rearing pups. Two months after mating, the female gives birth to between three and twelve pups. Pups weigh between 0.44 and 1.10 pounds at birth and are born blind and toothless. The male hunts for food and brings it back to the female while she nurses. The pups are weaned by two months of age and fight with each other to establish dominance. By June or July, the family leaves the den to hunt and patrol its territory. Territory is marked with urine and scratches in the ground. Pups gain the size of their parents by eight months and their full weight at nine months. Some leave their parents in August, but others may remain with the family much longer. Females that do not mate the following year may help their mother or sisters raise young. In the wild, coyotes may live 10 years. While they may be preyed upon by mountain lions, wolves, or bears, most die from hunting, disease, or automobile collisions. In captivity, a coyote may live 20 years. Coyote pups resemble fox or wolf pups. Matt Stirn / Aurora Photos / Getty Images Hybrids Coyotes and wolves sometimes mate, producing coywolf hybrids. In fact, most wolves in North America carry coyote DNA. Although uncommon, coyotes and dogs sometimes mate and produce coydogs. Coydogs vary in appearance, but tend to retain the shyness of coyotes. Conservation Status The IUCN categorizes the conservation status of the coyote as least concern. The species is abundant throughout its range, with stable or increasing populations. Humans pose the primary threat to coyotes. Ironically, control efforts may have led to the species expansion, as persecution alters coyote behavior and increases litter sizes. Coyotes and Humans Coyotes are hunted for fur and to protect livestock. Historically, they were eaten by trappers and indigenous people. Coyotes have adapted to human encroachment to the point where there are populations of urban coyotes. Coyote pups are readily domesticated, but they tend not to make ideal pets because of their scent and shyness around strangers. Sources Cartaino, Carol. Myths Truths about Coyotes: What You Need to Know about Americas Most Misunderstood Predator. Readhowyouwant.com. 2012. ISBN 978-1-4587-2668-1.Gier, H.T. Ecology and Behavior of the Coyote (Canis latrans). In Fox, M. W. (ed.). The Wild Canids: Their systematics, behavioral ecology, and evolution. New York: Van Nostrand Reinhold. pp. 247–262, 1974. ISBN 978-0-442-22430-1.  Kays, R. Canis latrans. The IUCN Red List of Threatened Species 2018: e.T3745A103893556. doi:10.2305/IUCN.UK.2018-2.RLTS.T3745A103893556.enTedford, Richard H.; Wang, Xiaoming; Taylor, Beryl E. Phylogenetic Systematics of the North American Fossil Caninae (Carnivora: Canidae). Bulletin of the American Museum of Natural History. 325: 1–218, 2009. doi:10.1206/574.1Vantassel, Stephen. Coyotes. Wildlife Damage Inspection Handbook (3rd ed.). Lincoln, Nebraska: Wildlife Control Consultant. p. 112, 2012. ISBN 978-0-9668582-5-9.