The replacement is stored

In compression, the algorithm carrys for repeat patterns in the denotation first rudiment and encodes these patters as in the raw symbolisms in a translated alphabet.The in the altogether alphabet is composed of symbols that argon longer (composed of more than numerals) than the symbols in the start alphabet. The compression arises when restate patterns in the experient alphabet argon replaced by a single symbol in the new alphabet. The replacement is stored in a lexicon that contains all mappings of the obsolescent alphabet patterns into the new alphabet symbols.The decompressing algorithm simply does the reverse carry through of the compression algorithm. The algorithm takes a look at the input stream in the new alphabet and looks up the dictionary for its corresponding pattern in the old alphabet.Unlike Huffman secret writing, LZW compression does not use hazard analysis and computation on the source selective information, needing tho to look at repeating patte rns in the source alphabet. LZW industrial plant scoop out on streams that contain multiple repeating patterns such as text files.Huffman coding on the separate hand snips best on streams where there is a disparity in relative frequencies between symbols. In LZW, a dictionary is use to map patterns in the old alphabet to symbols in the new alphabet, the dictionary organismness constructed from repeating patterns.In Huffman, symbol mappings atomic number 18 establish on the frequencies of the symbols in the source alphabet. Additionally, the bit length of the new symbols in LZW is unceasing trance the bit length for the new symbols in Huffman is variable, depending on the frequency of the source symbols.Wireless Mobile Ad-hoc Networks (MANET) and Wireless Sensor Networks argon two similar kinds of radio set technology. A MANET is a self-configu parry cyberspace the result organism an arbitrary topology. There is no mend infrastructure between the nodes and their only desc ent to each other is their proximity to superstar another.However, that may not be unbent for demodulator networks. Some sensor network protocols specify a specific topology. In the case of IEEE 802.15.4, it al confuseds for two kinds of topologies, a ring topology and a lucifer to peer topology.Another difference is complexity. The nodes of sensor networks are broadly much simpler than in MANETs. Sensor nodes typically include only a transceiver faculty for chat, a sensor and a microcontroller.This is because of the comparatively simpler uses for the sensor such as entropy collection and gathering. In contrast, nodes of a MANET testament generally be more complex, being made up of complete laptops, PDAs or other high level communication devices.A third difference is in the data pass judgment. Sensor networks are generally diminished data rate systems while MANETs get down higher data rates. Bit rates in MANETs like 802.11 are heedful in Mbps while those in 802.15.4 and Zigbee are in kbps only. Fourth is power consumption, MANET nodes are designed to be mains powered or only to be reliant on batteries for a short amount of eon (generally a few hours).On the other hand, sensor networks will generally use low power components to stretch the power of the assault and battery for weeks or months on end. Lastly, in MANETs, nodes are envisioned to be constantly direct data to one another while in sensor networks, nodes are anticipate to be in a pile or quiet mode for well-nigh of the time.This is due to the amount of data change in MANETs compared to sensor networks which may only need to throw data to the server on specified times.If we take the mannikin of the ZigBee sensor network protocol, we can depict three layers from the OSI model at work in the ZigBee protocol. In the ZigBee protocol, its uses the IEEE 802.15.4 standard for the PHY and mackintosh portion of the DLL layer. The ZigBee specification on the other hand serves as the upper la yers for the wireless sensor network.