紅外傳感器畢業(yè)設(shè)計外文翻譯---移動目標(biāo)點數(shù)與紅外傳感器網(wǎng)絡(luò)-其他專業(yè)(編輯修改稿)
2025-02-24 01:03 本頁面
【文章內(nèi)容簡介】 and supports runtime loading of standard ELF files. The Contiki kernel is eventdriven, like TinyOS, but the system supports multithreading on a perapplication basis. Unlike the eventdriven Contiki kernel, the MANTIS kernel is based on preemptive multithreading. With preemptive multithreading, applications do not need to explicitly yield the microprocessor to other processes. Introduction to Wireless Sensor Node A sensor node, also known as a mote, is a node in a wireless sensor work that is capable of performing processing, gathering sensory information and municating with other connected nodes in the work. Sensor node should be in small size, consuming extremely low energy, autonomous and operate unattended, and adaptive to the environment. As wireless sensor nodes are microelectronic sensor device, they can only be equipped with a limited power source. The main ponents of a sensor node include sensors, microcontroller, transceiver, and power source. Sensors are hardware devices that can produce measurable response to a change in a physical condition such as light density and sound density. The continuous analog signal collected by the sensors is digitized by AnalogtoDigital converter. The digitized signal is then passed to controllers for further processing. Most of the theoretical work on WSNs considers Passive and Omni directional sensors. Passive and Omni directional sensors sense the data without actually manipulating the environment with active probing, while no notion of “direction” involved in these measurements. Commonly people deploy sensor for detecting heat (. thermal sensor), light (. infrared sensor), ultra sound (. ultrasonic sensor), or electromagism (. magic sensor). In practice, a sensor node can equip with more than one sensor. Microcontroller performs tasks, processes data and controls the operations of other ponents in the sensor node. The sensor node is responsible for the signal processing upon the detection of the physical events as needed or on demand. It handles the interruption from the transceiver. In addition, it deals with the internal behavior, such as applicationspecific putation. The function of both transmitter and receiver are bined into a single device know as transceivers that are used in sensor nodes. Transceivers allow a sensor node to exchange information between the neighboring sensors and the sink node (a central receiver). The operational states of a transceiver are Transmit, Receive, Idle and Sleep. Power is stored either in the batteries or the capacitors. Batteries are the main source of power supply for the sensor nodes. Two types of batteries used are chargeable and nonrechargeable. They are also classified according to electrochemical material used for electrode such as NiCd(nickelcadmium), NiZn(nickelzinc), Nimh(nickel metal hydride), and LithiumIon. Current sensors are developed which are able to renew their energy from solar to vibration energy. Two major power saving policies used are Dynamic Power Management (DPM) and Dynamic Voltage Scaling (DVS). DPM takes care of shutting down parts of sensor node which are not currently used or acti
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