Abstract: A wireless device and method for managing a multicast group within a wireless network are disclosed. The wireless device is included in a first multicast group in which data is directly sent between member devices or data is sent using hopping between the member devices. The wireless device includes a reception unit, a determination unit, and a transmission unit. The reception unit receives a join request for joining a second multicast group from a joining device that attempts to join the second multicast group. The determination unit extracts information about the second multicast group from the join request, and determines whether the second multicast group is identical with the first multicast group based on the information about the second multicast group. The transmission unit forwards the join request to another device or sends a response to the join request to the joining device based on a result of the determination.

Abstract: A wireless device and method for managing a multicast group within a wireless network are disclosed. The wireless device is included in a first multicast group in which data is directly sent between member devices or data is sent using hopping between the member devices. The wireless device includes a reception unit, a determination unit, and a transmission unit. The reception unit receives a join request for joining a second multicast group from a joining device that attempts to join the second multicast group. The determination unit extracts information about the second multicast group from the join request, and determines whether the second multicast group is identical with the first multicast group based on the information about the second multicast group. The transmission unit forwards the join request to another device or sends a response to the join request to the joining device based on a result of the determination.

Abstract: A direct digital frequency synthesizer and a synthesizing method thereof. The direct digital frequency synthesizer uses a hybrid digital to analog converter, which matches output data of a phase accumulator to a sine wave amplitude using a hybrid DAC, including a non-linear DAC and a linear DAC. The non-linear DAC outputs a direct base point current using some bits of output data of a phase accumulator, causing the linear DAC to output a gradient current based on gradient information generated using other bits of the output data of the phase accumulator. These currents are summed for the analog output.

Abstract: A low-profile antenna is provided. A laminated substrate is formed into a structure in which a plurality of substrates having different permittivities are stacked, and a radiator consists of a plurality of unit patches disposed on an upper surface of the laminated substrate and generates an electric field perpendicular to the upper surface of the laminated substrate. Ground vias are formed from the respective unit patches to a ground plane disposed on a lower surface of the laminated substrate through the substrates constituting the laminated substrate. In the low-profile antenna, the radiator consisting of the plurality of patches is disposed on the upper surface of the laminated substrate having a structure in which the plurality of substrates are stacked to generate a magnetic loop around the patches, so that vertical polarized signals can be received due to a magnetic field perpendicular to the upper surface of the laminated substrate.

Abstract: Provided are an apparatus and method for generating panorama images and an apparatus and method for tracking an object using the same. The apparatus for generating panorama images estimates regional motion vectors with respect to respective lower regions set in an image frame, determines a frame motion vector by using the regional motion vectors based on a codebook storing sets of normalized regional motion vectors corresponding to a camera's motion and then accumulates motion mediating variables computed with respect to respective continuous image frames to determine an overlapping region, and matches the overlapping regions to generate a panorama image.