Abstract: A semiconductor device including a first interlayer insulating film; a conductive pattern in the first interlayer insulating film; a resistance pattern on the conductive pattern; an upper etching stopper film spaced apart from the resistance pattern, extending in parallel with a top surface of the resistance pattern, and including a first metal; a lower etching stopper film on the conductive pattern, extending in parallel with a top surface of the first interlayer insulating film, and including a second metal; and a second interlayer insulating film on the upper etching stopper film and the lower etching stopper film, wherein a distance from a top surface of the second interlayer insulating film to a top surface of the upper etching stopper film is smaller than a distance from the top surface of the second interlayer insulating film to a top surface of the lower etching stopper film.

Abstract: A fuel cell system includes: a supply flow path configured to supply reactant gas; a first branch flow path branching off from an outlet end of the supply flow path and configured to guide the reactant gas to a first fuel cell stack; a second branch flow path branching off from the outlet end of the supply flow path and configured to communicate with the first branch flow path and guide the reactant gas to a second fuel cell stack; and an inlet area change part disposed in a boundary zone between the first branch flow path and the second branch flow path and configured to selectively change inlet areas of the first and second branch flow paths. Efficiency in discharging condensate water is increased and performance and operational efficiency are improved.

Abstract: Provided is a hybrid beaconing method in which a centralized beaconing scheme and a distributed beaconing scheme are combined. In the hybrid beaconing method, a beaconing scheme is converted according to a network condition, and a centralized beaconing scheme or a distributed beaconing scheme is used to maintain an optimum network status.

Abstract: Provided is a method and apparatus for efficiently transmitting and receiving a frame including a header and a payload in a communication system. If the number of repeated items in the content of a header of the frame is high, specific preambles are allocated to the repeated items and the repeated items are omitted. Accordingly, data transfer efficiency can be improved.

Abstract: The present invention relates to a method and apparatus for managing a backup channel in a multi-channel environment. According to an aspect of the present invention, the method of managing a backup channel in a multi-channel environment includes transmitting a control region of a super frame through a first channel constituting the multi-channel and transmitting a data region of the super frame to a destination terminal through a second channel constituting the multi-channel. A transmission quality of the first channel is acquired using the control region transmitted through the first channel.

Abstract: A method and apparatus for detecting a heterogeneous communication system is provided. The apparatus include a radio frequency (RF) signal reception unit configured to receive a signal from a particular communication system, a silent duration evaluation unit configured to evaluate a silent duration between frames on the basis of the received signal, and a system type decision making unit configured to determine the type of the particular communication system on the basis of the evaluated silent duration.

Abstract: A resource reservation method between a master device and a slave device or between slave devices in a centralized network. In resource reservation between slave devices, optimal resources may be allocated by performing link measurement between the slave devices before allocating the resources.

Abstract: A channel switching method is provided for a base station to allocate a slot for data exchange with each of a plurality of terminals in a frequency channel that is not used by an incumbent user (IU). The method includes include transmitting a channel switching message for requesting to switch to a backup channel when a signal of the IU is sensed in the frequency channel; transmitting a beacon frame via the backup channel, wherein the beacon frame comprises allocation information about slots which are in the frequency channel and which are respectively allocated to each of the plurality of terminals; and allocating the slot for data exchange with each of the plurality of terminals to the backup channel according to the allocation information, and communicating with each of the plurality of terminals.

Abstract: The present invention relates to relay customer premises equipment (RCPE) for exchanging operational information and coexistence information of each cell between adjacent cells in a cellular system. The present invention enables effective control between multiple cells by directly transmitting operational information and coexistence information between cells over air links.

Abstract: The present invention relates to a method and apparatus for managing a backup channel in a multi-channel environment. According to an aspect of the present invention, the method of managing a backup channel in a multi-channel environment includes transmitting a control region of a super frame through a first channel constituting the multi-channel and transmitting a data region of the super frame to a destination terminal through a second channel constituting the multi-channel. A transmission quality of the first channel is acquired using the control region transmitted through the first channel.

Abstract: A method and apparatus for detecting a heterogeneous communication system is provided. The apparatus include a radio frequency (RF) signal reception unit configured to receive a signal from a particular communication system, a silent duration evaluation unit configured to evaluate a silent duration between frames on the basis of the received signal, and a system type decision making unit configured to determine the type of the particular communication system on the basis of the evaluated silent duration.

Abstract: A method and an apparatus for transmitting a packet in a communication system are provided. The method for transmitting a packet in a communication system includes receiving a compression packet use request message from a receiver; generating a specific preamble and transmitting the compression packet to a receiver; wherein the compression packet is generated by omitting information on overlapping frame header among a frame to be transmitted and attaching the specific preamble including the information on the omitted frame header.

Abstract: Provided is a method and apparatus for efficiently transmitting and receiving a frame including a header and a payload in a communication system. If the number of repeated items in the content of a header of the frame is high, specific preambles are allocated to the repeated items and the repeated items are omitted. Accordingly, data transfer efficiency can be improved.

Abstract: A resource reservation method between a master device and a slave device or between slave devices in a centralized network. In resource reservation between slave devices, optimal resources may be allocated by performing link measurement between the slave devices before allocating the resources.

Abstract: Provided is a hybrid beaconing method in which a centralized beaconing scheme and a distributed beaconing scheme are combined.

Abstract: Provided is a contention-based data communication apparatus and method that may notify that a radio resource is to be used using a search signal prior to transmitting a communication frame, and may transmit data based on a priority when a search signal received from another communication apparatus is detected.

Abstract: In a cognitive radio system, when communication in an operational channel is determined to be discontinued due to that an incumbent user (IU) entering the operational channel that is currently being used or due to that an excessive interference occurring in the operational channel, the operational channel is switched to a pre-arranged channel. However, since some parameters are different between the operational channel and the pre-arranged channel, an initialization procedure has to be performed to allow the cognitive radio system to be adapted to those some parameters. Since an initialization technique aiming for this situation is not developed yet, a conventional cognitive radio system uses a general initialization technique used to initially operate a system. However, the general initialization technique has to allow the system to be adapted to many parameters so that it takes a relatively long initialization time.

Abstract: Provided are a transmission power determining method and an apparatus thereof for parallel transmission of a plurality of streams. In a wireless communication system, the transmission power determining method and apparatus determine a transmission power suitable for allowing the plurality of streams to be simultaneously and reliably transmitted in a mutually permissible interference range, and use a Hidden Handshaking (HHS) procedure to determine the transmission power. By doing so, it is possible to perform reliable channel allocation and to reliably transmit the plurality of streams.

Abstract: Provided are a method of managing multiple channels in a single network, and a network management device, also referred to as a network management system. According to the method and the network management device, all devices in one network that operate by using multiple channels share core information, and are effectively controlled.

Abstract: Provided are a beacon re-broadcasting apparatus, a beacon re-broadcasting method, and an initial access request method in a wireless network. In the re-broadcasting apparatus and method, a beacon frame including beacon information for communications in the wireless network and information on an echo beacon slot allocated for beacon re-broadcasting among time slots of a superframe is received from a management device for managing the wireless network in which a plurality of terminals communicated with each other through the superframe including time-divided time slots, and the beacon information is re-broadcasted during the echo beacon slot. Accordingly, the beacon information can be received in various environments, and the beacon information can be received to an adjacent network in addition to the corresponding network. Therefore, frequency resources can be shared and effectively used between networks, and convenience and efficiency in network operation can be maximized.