Abstract: Disclosed are a method of transmitting/receiving streaming data, to which a bit rate suitable for a mobile communication terminal is applied, in a communication system including a server and the mobile communication terminal, and a communication system therefor. The communication system include the server for converting multimedia data into the streaming data, and transmitting the streaming data to the mobile communication terminal; and the mobile communication terminal for, on receiving the streaming data from the server, collecting streaming parameters for use to determine the bit rate, and newly determining the bit rate.

Abstract: A remote access unit (RAU) apparatus, coupled to a central station (CS) of an RoF network through at least one optical fiber, and which RAU apparatus includes at least one antenna, includes: first and second antenna ports coupled to the at least one antenna; first and second optical fiber ports coupled to the at least one optical fiber; a first coupler for decoupling a first downstream signal of a first duplexing method and a second downstream signal of a second duplexing method, which are input through the first optical fiber port; a circulator for outputting the first downstream signal input from the first coupler to the first antenna port and outputting a first upstream signal of the first duplexing method input from the first antenna port to the second optical fiber port; and a second coupler for outputting the second downstream signal input from the first coupler to the second antenna port and outputting a second upstream signal of the second duplexing method input from the second antenna port to the sec

Abstract: A method for compressing an extension field to be selectively included in a Real-time Transport Protocol (RTP) header is provided. It is determined whether an RTP header extension field is included in the RTP header. Information indicating a determination result is recorded. Profile information of the RTP header extension field is recorded. Total length information of the RTP header extension field is recorded. Information indicating whether changed data exists is recorded using a header extension information map.

Abstract: A method for performing an encrypted voice call between a first terminal and a second terminal supporting a Voice over Internet Protocol (VoIP)-based voice call. In the method, the first and second terminals generate and store a bio key using biographical (bio) information of a user in advance before performing a voice call, the first terminal sends a request for a voice call to the second terminal and establishing a session, the first and second terminals exchange and store a bio key stored in each terminal, and the first and second terminals generate a session shared key using the exchanged bio key and starting a Secure Real-time Transport Protocol (SRTP) session, and a restored bio key by acquiring bio information from received data. User authentication is then performed by comparing the bio key with the restored bio key.

Abstract: Disclosed is a remote access unit for transmitting and receiving upstream and downstream data in which channels having different transmission scheme are multiplexed, and an optical network for bi-directional wireless communication using same. The remote access unit includes an antenna for receiving the downstream data and wirelessly transmitting same and for receiving the upstream data and providing same to the remote access unit, a switch for outputting downstream time division channels of the downstream data to the antenna and for receiving upstream time division channels of the upstream data from the antenna, and a controller for controlling the switch in order to prevent the upstream and downstream time division channels from overlapping.

Abstract: Provided are a gas sensing apparatus and a gas sensing method using the apparatus. The gas sensing apparatus includes a detection chamber, a light source, a light sensor, a gas source, and a controller. The light source is disposed at one end of the detection chamber, and a light sensor is disposed at the other end of the detection chamber. The gas source provides gas to the detection chamber. The controller controls the light source and the light sensor. The light source includes a laser supplying laser light, and a light scanner reflecting and scanning the laser light in the detection chamber. The controller includes a phase sensitive detector electrically connected to the light sensor.

Abstract: A system and method for video quality assessment includes utilizing codec auxiliary information related to the encoding and decoding process to enhance performance of picture quality assessment. In a video transmission system, video quality assessment can be accurately performed in real time with reduced computational load upon the client. In particular, the server performs first picture quality assessment and sends the assessment result to the client, and the client performs second picture quality assessment only when a transmission error occurs to reduce the computational load on the client.

Abstract: A method for setting an output bit rate for video data transmission in a WiBro system in which an uplink state value for a predetermined unit time is calculated to determine an uplink network state of the predetermined unit time. An average of uplink state values for a predetermined number of unit times is calculated, and a video encoding bit rate is increased if the average of the uplink state values is larger than a predetermined first threshold. However, the video encoding bit rate is decreased if the average of the uplink state values is less than a predetermined second threshold.

Abstract: Disclosed is a method for detecting a scene change in real time in order to control a moving-picture encoding data rate, the method including: dividing a current frame into a plurality of regions, and calculating a dissimilarity metric (DM) of each divided region; determining if the dissimilarity metric of each divided region is beyond a preset reference value; calculating the number of regions, the dissimilarity metric of which is beyond the preset value, in the current frame; and determining that a scene change occurs in the current frame, when the number of regions, the dissimilarity metric of which is beyond the reference preset value, is equal to or greater than a preset threshold value.

Abstract: Access by multiple hosts, such as computers, to a data storage device by way of a network while maintaining data integrity. In one embodiment, a method for accessing the storage device includes acquiring a resource “lock” that provides exclusive access to one of the hosts at a time. In another embodiment, the file systems of a first and second host provide file system attributes stored in a storage device to provide mutually exclusive access for each host to free blocks of the device. In another embodiment, a networked system contains a first host having exclusive direct access to a storage device over a digital network. A second host requiring access to the storage device communicates with the first host by way of the digital network. File access requests generated by the second host are transferred by a redirection filter driver within the second host to the first host.

Abstract: A server architecture based on asymmetric 3-way TCP (ATCP) is disclosed that can distribute the work among multiple processors. In particular, the server system has a front-end server receiving a service request from a client. The server system also has a back-end server that receives a command from the front-end server. The back-end server sends the result back directly to the client in a pseudo packet that looks like a packet sent from the front-end server. The pseudo packet has the IP address and the port number of the front-end server. A scalable system is achieved because the bottleneck through the front-end server is avoided.

Abstract: Disclosed is a method for controlling bit rates in consideration of wireless channel environment by an apparatus that transmits and receives moving picture encoding data via a wireless network. The apparatus for transmitting/receiving data through a wireless communication network connected to the apparatus including a channel state analyzing unit for analyzing a wireless channel environment, an encoding controller for generating control information containing information about a quantization parameter, skip or non-skip of frames indication, frame type indication, and use or non-use of an Error Resilient Tool (ERT) indication, in consideration of an analyzation result received from the channel state analyzing unit, a moving picture encoding unit for encoding incoming moving picture data, based on the control information received from the encoding controller; and a data transmitting/receiving unit for transferring the encoded moving picture data through the wireless channel to an exterior.

Abstract: Access by multiple hosts, such as computers, to a data storage device by way of a network while maintaining data integrity. In one embodiment, a method for accessing the storage device includes acquiring a resource “lock” that provides exclusive access to one of the hosts at a time. In another embodiment, the file systems of a first and second host provide file system attributes stored in a storage device to provide mutually exclusive access for each host to free blocks of the device. In another embodiment, a networked system contains a first host having exclusive direct access to a storage device over a digital network. A second host requiring access to the storage device communicates with the first host by way of the digital network. File access requests generated by the second host are transferred by a redirection filter driver within the second host to the first host.

Abstract: An optical transmitter for generating return-to-zero alternative-mark-inversion (RZ-AMI) optical signals and a method for generating the optical signals are provided. The optical transmitter includes a light source radiating at its output an intensity-modulated light beam based upon intensity of a first data, a precoder for precoding a second data having the information identical to the first data, and a Mach Zehnder modulator for phase-modulating the intensity-modulated light on basis of the precoded second data to generate a return-to-zero alternative-mark-inversion (RZ-AMI) optical signal.

Abstract: A cross-layer optimization method for controlling a bit rate of a video coder/decoder (codec) in video data transmission for wireless devices such as a wireless broadband (WiBro) system terminal that adapts to changing transmission/reception characteristics and usage. The method typically includes checking, by a sender, radio channel state information of a sender side and a receiver side; determining, by the sender, a transmission bit rate of a video codec by using the radio channel state information of the sender side; and adjusting, by the sender, the transmission bit rate of the video codec by using the radio channel state information of the receiver side when a communication network used by a receiver typically based on the type of a communication network being used by the sender.

Abstract: An interband resonant tunneling intersubband transition laser is disclosed, and includes a semiconductor substrate, and a first cladding layer, an active region structure layer and a second cladding layer formed on the semiconductor substrate. The active region structure layer includes quantum well layers and quantum barrier layers that are alternately stacked and have a broken energy bandgap. Thus, the interband resonant tunneling intersubband transition laser operates in a cascade mode in which an intersubband radiative transition and interband tunneling of carriers consecutively and repetitively occur in the active region structure layer, and thus can achieve a high output from a simple, compact structure.

Abstract: Disclosed is a data transmission method for an MBS in a broadband wireless access system. The method includes the steps of constructing a Wibro frame by adding an FEC zone to a downlink portion of the Wibro frame by a radio access station, the FEC zone containing an FEC packet for performing a packet-based FEC scheme; and transmitting data to a plurality of mobile stations by the radio access station, the Wibro frame constructing the data.

Abstract: A system and method for retransmitting an Internet protocol packet for terrestrial digital multimedia broadcasting (DMB) service are provided, in which a PES packetizer and an MPEG-2 TS multiplexer are removed; video, audio, and data signals are individually carried by RTP packets; and a receiver extracts object clock reference (OCR) included in a PEG-4 SL, and synchronizes a system clock and controls buffers by means of the OCR.

Abstract: A mobile communication system for providing a multicast/broadcast service is disclosed. The mobile communication systems comprise a base station that encodes video data of the mobile communication system into scalable bit streams and adaptively modulates and channel codes the scalable bit streams. A mobile communication terminal receives, demodulates and channel decodes the scalable bit streams transmitted from the base station and performs a process for scalable decoding the bit streams according to reception sensitivity. Overall system efficiency can be improved while increasing a transmission rate using scalable video coding according to channel characteristics between the mobile communication terminal and the base station in the multicast/broadcast service. Quality of service (QoS) can be provided based on the performance of the mobile communication terminal.

Abstract: The present invention relates to a multi fixed-point cell for calibrating a thermometer and a thermometer calibration apparatus using the same, wherein measuring errors can be checked by using a property of constant temperature of a metal on the basis of a phase transition and wide range of temperature region can be measured by one time calibration, thereby capable of increasing efficiencies of time and cost which are taken for calibration. In a multi fixed-point cell for calibrating a thermometer according to the present invention, a thermometer inserting hole in which a thermometer is inserted is formed at one side and at least two reference material inserting holes in which reference materials having different phase transition temperatures are inserted respectively are formed on a same plane as that of the thermometer inserting hole so as to be spaced apart each other.