摘要:
Provided is a method of preventing a data collision that occurs when two or more child nodes simultaneously transmit data to a parent node in a ZigBee network having a tree routing scheme and operating in a beacon mode. In the ZigBee system having the tree routing scheme and operating in the beacon mode, data communication to the parent node is performed in a beacon frame of the parent node. Here, when several child nodes exist under a single parent node, the child nodes transmit data to the parent node at the moment of receiving the beacon of the parent node, so that the data collision may occur when the child nodes simultaneously transmit the data to the parent node in the beacon frame of the parent node. In the method of preventing a data collision, each of the two or more child nodes is set to wait for its guard time (delay time) when transmitting data to the parent node to induce a normal slotted carrier sense multiple access with collision avoidance (CSMA-CA) operation. Therefore, the data collision can be prevented.
摘要:
Provided is a method for determining superframe to efficiently perform beacon scheduling by allocating superframe lengths which are different according to a routing depth of sensor nodes in a ZigBee based wireless sensor network. The method for determining a superframe for beacon scheduling, includes the steps of: receiving a beacon from a neighboring node and grasping information on a superframe used by the neighboring nodes; and determining a transmission time and a length of own superframe based on superframe information of the grasped neighboring node.
摘要:
Provided is a method for determining superframe to efficiently perform beacon scheduling by allocating superframe lengths which are different according to a routing depth of sensor nodes in a ZigBee based wireless sensor network. The method for determining a superframe for beacon scheduling, includes the steps of: receiving a beacon from a neighboring node and grasping information on a superframe used by the neighboring nodes; and determining a transmission time and a length of own superframe based on superframe information of the grasped neighboring node.
摘要:
Provided are a localization apparatus for recognizing a location of a node in a sensor network and a method thereof. The method includes the steps of: a) selecting reference nodes from a plurality of anchor nodes to be used for triangulation; and b) obtaining location information of a target node by performing triangulation using the selected reference node, wherein in the step a), the reference nodes are selected by removing anchor nodes having obstacle factor from a plurality of the anchor nodes where the obstacle factor causes error in a distance measured by the target node.
摘要:
Provided are a localization apparatus for recognizing a location of a node in a sensor network and a method thereof. The method includes the steps of: a) selecting reference nodes from a plurality of anchor nodes to be used for triangulation; and b) obtaining location information of a target node by performing triangulation using the selected reference node, wherein in the step a), the reference nodes are selected by removing anchor nodes having obstacle factor from a plurality of the anchor nodes where the obstacle factor causes error in a distance measured by the target node.
摘要:
A method and an apparatus for assigning a time slot for transmitting a beacon in a wireless sensor network operated in a beacon mode are provided. In the method and apparatus for assigning a time slot according to the present invention, the total time slots assigned to the network are divided into N blocks and a node to which a time slot is exclusively assigned, among nodes to which a specific node is capable of directly and wirelessly transmitting, is selected as a parent node, the network is divided into two or more regions centering the parent node, a block having the time slot assigned to the parent node and adjacent blocks, among the N blocks, are respectively assigned to the regions, a time slot having been yet unassigned, among the time slots belonging to the block assigned to the region to which the specific node belongs among the divided regions, is assigned as the time slot of the specific node.
摘要:
Provided are a method and apparatus for setting a routing path in a wireless sensor network. The apparatus for setting a routing path includes a neighbor table storing information of a peripheral device within wireless communication distance of a transmitter transmitting data; a searching unit sequentially searching whether at least one of an address of a destination, a parent address or ancestor address of the destination representing an address of a receiver receiving data transmitted by the transmitter exists or not in the neighbor table; and a link quality indicator (LQI) judging unit transmitting the data to the receiver when a LQI value of the address is greater than a value that is previously set in a case in which an address is searched in the searching unit.
摘要:
Provided are an apparatus and method for broadcasting data, and an apparatus and method for broadcasting response data, of a sensor node in a beacon mode in a wireless sensor network system including a plurality of nodes. According to the apparatus and method for broadcasting data, an admission application message requesting an admission of a sensor node is transmitted to the wireless sensor network system, in which time-division time slots are assigned to each of the nodes of the wireless sensor network system, wherein, in the time-division time slot, the reception function of the node is activated and sensing data is transmitted; a beacon frame is received, which includes information that indicates a broadcasting time slot among the time-division time slots, wherein, in the broadcasting time slot, the reception function of each of the nodes of the wireless sensor network system having received the admission application message, is activated at the same time; and broadcasting data is transmitted during the broadcasting time slot. Accordingly, broadcasting data can be efficiently transmitted in a beacon mode of the wireless sensor network system.
摘要:
An ion implanting system and a wafer holding apparatus therefor are provided. The ion implanting system includes x- and y-axis rotating parts; first and second angle measuring circuits; and a controller. The x-axis rotating part rotates a main surface of a wafer about an x-axis, and the y-axis rotating part rotates the main surface of the wafer about a y-axis. The first angle measuring circuit is rotated along with the main surface of the wafer and measures a tilt angle of the main surface of the wafer with respect to the x-axis. The second angle measuring means is rotated along with the main surface of the wafer and measures a rotating angle of the main surface of the wafer with respect to the y-axis. The controlling part, when the measured tilt angles are different from target tilt angles, controls the x- and y-axis rotating parts such that the measured tilt angles are equal to the target tilt angles. In the present invention, the ion implanting system and the wafer holding apparatus therefor can measure and monitor an incidence angle of an ion beam with respect to a tilted wafer.
摘要:
A touch sensing device includes a touch screen panel including a touch sensor configured to generate a first electrical change corresponding to a touch and a touch controller configured to detect touch position data with respect to an area on the touch screen panel associated with the touch, based on the first electrical change or the touch sensor.