Abstract: Disclosed herein is a stack type surface acoustic wave package. The surface acoustic wave package comprises a first bare chip having a plurality of electrodes formed thereon, a second bare chip having a plurality of electrodes and via-holes formed thereon, a connecting portion electrically connecting the first bare chip to an upper surface of the second bare chip such that the electrodes of the first bare chip face the electrodes of the second bare chip, and a sealing member provided on the first and second bare chips to form an air-tight space on an operating surface between the first and second bare chips. The surface acoustic wave package can prevent deformation due to thermal impact from the outside during a packaging process, enhancing reliability of the product, minimizing the size of the product, and reducing manufacturing costs by reducing the number of components and material costs.

Abstract: A sensor network for aggregating data and data aggregation method. The sensor network includes a representative sensor node for collecting information in a predefined grid area that includes at least two sensor nodes, and transmitting the collected information of the predefined grid area; and a sink node for selecting the representative sensor node by randomly searching the sensor nodes in the predefined grid area and aggregating information of the predefined grid area from the selected representative sensor node. Accordingly, since the amount of the delivered data reduces and the overload is also lowered, the power consumption for the data transmission over the sensor network can be reduced. In addition, it is possible to control the data transmission rate depending on the correlation, and the quality of the delivered data can be enhanced.

Abstract: Disclosed is a bumper system including a bumper cover, an energy absorber formed of a synthetic resin material through a foam molding process, an impact beam for supporting the energy absorber, the impact beam being formed of a glass mat thermoplastic and having a “C”-shaped section, and a stay for connecting the impact beam to a vehicle body. Tips are formed on front upper and lower portions of the impact beam, and a web portion is formed on the impact beam between the tips. Tip insertion grooves in which the tips are inserted are formed on an inner surface of the energy absorber, and a pressure receiving surface corresponding to the web portion is formed on the inner surface of the energy absorber.