Abstract: A tellurite glass as a glass material of optical fiber and optical waveguide has a composition of 0<Bi2O3≦20 (mole %), 0≦Na2O≦35 (mole %), 0≦ZnO≦35 (mole %), and 55≦TeO2≦90 (mole %). The tellurite glass allows an optical amplifier and a laser device that have broadband and low-noise characteristics. In a splicing structure of non silica-based optical fiber (as a first fiber) and a silica-based optical fiber (as a second fiber), optical axes of the first and second optical fibers are held at different angles &thgr;1 and &thgr;2 (&thgr;1≠&thgr;2) respectively from a vertical axis of a boundary surface between their spliced ends, and a relationship between the angles &thgr;1 and &thgr;2 satisfies Snell's law represented by an equation of sin &thgr;1/sin &thgr;2=n2/n1 (where n1 is a refractive index of the first optical fiber and n2 is a refractive index of the second optical fiber) at the time of splicing the first and second optical fibers.

Abstract: To suppress S/N degradation due to optical amplification and generation of a nonlinear optical effect in a dispersion compensating fiber, and compensate for a loss due to the dispersion compensating fiber without incorporating a long fiber inside a receiver, part of an optical transmission line is constructed by a dispersion compensating fiber and at least part of the optical transmission line is designed to have a Raman gain or a distributed gain. A pump light to obtain a Raman gain or a distributed gain is transmitted from at least one of a transmitter, a receiver, and a repeater to the optical transmission line.

Abstract: An optical waveguide component includes an optical waveguide chip formed with an optical waveguide, first and second connecting end members mounted on opposite end portions of the waveguide chip, housings for protecting the waveguide chip, and first and second receptacles mounted to end faces of the housings. When optical connector plugs are inserted into connector-plug accommodation holes of the first and second receptacles, the connector plugs are adequately positioned in the connector-plug accommodation holes by means of a guiding function of these holes, so that guide pins projecting from tip end faces of the connecting end members are fitted into guide-pin accommodation holes formed in the connector plugs, whereby optical fibers held by the connector plugs and the waveguide of the waveguide component are connected accurately and easily.

Abstract: A secret communication and authentication scheme based on a public key cryptosystem in which a decryption speed is improved while maintaining a security level. In the RSA type secret communication, a plaintext is expressed in a form of a k-digit base n number and a ciphertext is obtained by applying a calculation using the first public key n and the second public key e to the base n number and transmitted. Then, from the received ciphertext, a lowest digit of the base n number is decrypted by using the first public key n and the second secret key d, upper digits of the base n number are sequentially decrypted by using a decrypted value of the lowest digit of the base n number at the receiver side, and the plaintext is recovered by using decrypted values of respective digits of the base n number. The Rabin type secret communication can also be realized by the similar scheme.

Abstract: A collecting agency supplies a collecting agency name and a money bag number to a service providing terminal. In response to dealing requests from user terminals, the service providing terminal sends, to the user terminals, information which contains the collecting agency name (Id) and the money bag number (Gb) supplied from the collecting agency. The user terminals generate digital signatures containing the received request information, affix the generated signatures to electronic tickets to be used, and send the electronic tickets with the signatures to the service providing terminal. The service providing terminal, which has received the used electronic tickets, collects those electronic tickets which include the same money bag number supplied from the collecting agency into a group (a money bag), and sends the group of electronic tickets to the collecting agency.

Abstract: A navigation method for guiding a user from a present position to a destination position includes inputting the present position and the destination position, inputting data from a geographic database and a road network database and selecting a route from the present position to the destination position, determining particularity of route guide map according to the area and the density of data representing the selected route, selecting necessary data for guiding a user according to the particularity and generating the route guide map, inputting data corresponding to the area from a spatial object network database and generating route guide sentence with respect to the route guide map, and manipulating information in the route guide map and route guide sentence and outputting the manipulated information.

Abstract: An optical fiber distribution module having a connection board, optical connector adaptors and a storage section is provided. An array of the optical connector adaptors forms the connection board, where the optical connectors connect in-use optical fibers. The storage section, located in a separate section of the module, stores optical fibers which are not-in use. The optical fiber distribution module also includes a plurality of cord sorting boards having a plurality of fiber cord passageways. The fiber cord passageways are configured to accommodate and retain at least one optical fiber such that the optical fiber is arranged between the connection board and the storage section. In addition, both the in-use and not-in use optical fibers insert into the fiber cord passageway.

Abstract: A scheme for interactive video manipulation and display of a moving object on a background image is disclosed. In this scheme a background image stored in a background image storage unit is read out and displayed on a screen, and a manipulation target spatial position is set on the screen. Then, a partial image to be synthesized and displayed is uniquely specified from partial images which are set in correspondence to spatial positions on the background image and representing an object moving on the background image, according to the manipulation target spatial position set by the setting step, and the partial image as specified by the specifying step is read out from a partial image storage unit, and synthesized and displayed at the manipulation target spatial position on the background image. A scheme for realizing a variable speed video playback with a playback speed different from a normal one is also disclosed.

Abstract: A surface shape recognition sensor of this invention includes at least a plurality of capacitance detection elements having sensor electrodes arranged in the same plane on an interlevel dielectric film formed on a semiconductor substrate to be insulated/isolated from each other, capacitance detection means for detecting the capacitances of the capacitance detection elements, and a stationary electrode disposed on the interlevel dielectric film to be insulated/isolated from the sensor electrodes. When an object to be recognized touches the upper surface of the stationary electrode, the capacitances detected by the capacitance detection elements change in accordance with the recesses/projections on the upper surface.

Abstract: In a trunk transmission network for transmitting information signals between nodes via paths, flexible path operation is achieved by setting up paths between source nodes and destination nodes after pre-classifying paths into a higher service class in which any loss of information occurring in that path is made good, and a lower service class which permits loss of information to occur in the path, and by arranging for each node, when it acts as a source node, to recognize the service class of the information signal it is sending to a destination node, and to select a path corresponding to that service class.

Abstract: In a subband echo cancellation for a multichannel teleconference, received signals x1(k), x2(k), . . . , xI(k) of each channel are divided into N subband signals, an echo y(k) picked up by a microphone 16j after propagation over an echo path is divided into N subband signals y0(k), . . . ,yN−1(k), and vectors each composed of a time sequence of subband received signals x1(k), . . . , xI(k) are combined for each corresponding subband. The combined vector and an echo cancellation error signal in the corresponding subband are input into an estimation part 19n, wherein a cross-correlation variation component is extracted. The extracted component is used as an adjustment vector to iteratively adjust the impulse response of an estimated echo path. The combined vector is applied to an estimated echo path 18n formed by the adjusted value to obtain an echo replica. An echo cancellation error signal en(k) is calculated from the echo replica and a subband echo yn(k).

Abstract: The present invention provides an image transmission method employing phase/amplitude resolution processing in which three-dimensional data of an object recorded as a holographic fringe pattern by means of reference light and light from the object are transmitted sequentially, and at the receiving side, the holographic fringe patterns received are displayed sequentially and with reference to the reproduced light, and the object is displayed in a three-dimensional manner; wherein, at the transmission side, the following processes are executed: a process in which the image of the holographic fringe pattern expressed in terms of complex numbers is decomposed into an amplitude component image and a phase component image, a process in which the high frequency component of the spatial frequency in the amplitude component image decomposed in this way is reduced, processing for converting the gradation in the phase component image is carried out, and each image is compressed and encoded after this processing, and a

Abstract: A method for performing a semantic analysis process on a computer system including a storage unit and an interface includes the steps of: receiving a syntactic tree generated from a natural language sentence text; determining whether an analysis object, which is one of nodes of the syntactic tree, is a verb phrase class which has a verb as a head or a non-verb phrase class which has mainly a noun as the head on the basis of subdivided type information of a phrase of the node with reference to first data stored in the storage unit; analyzing a relation between a verb in the analysis object and a deep case of the verb when the analysis object is the verb phrase class; analyzing a modificative relation in the analysis object when the analysis object is the non-verb phrase class; generating a semantic structure of the natural language sentence text wherein the semantic structure comprises semantic frames corresponding to nodes of the syntactic tree, at least two semantic frames of the semantic frames being linked

Abstract: A video caption detection scheme capable of detecting captions from the coded video data which are coded by using a combination of predictive coding and motion compensation, without requiring the decoding of coded video data into frame images. In this video caption detection scheme, whether each pixel/block in the video data is coded by using inter-frame correlation without using motion compensation or not is judged. Then, a region in the video data at which pixels/blocks that is judged as being coded by using inter-frame correlation without using motion compensation are concentrated time-wise and space-wise, is detected as a caption region. The detection can be realized by counting a frequency of appearance of a pixel/block which is judged as being coded by using inter-frame correlation without using motion compensation, at each pixel/block position of a frame over a prescribed counting period, and then comparing the counted frequency of appearance with a prescribed threshold value.

Abstract: A mixer circuit for frequency conversion operates with low power supply voltage lower than 1 V. The circuit comprises a first pair of N-channel MOS transistors and a second pair of N-channel MOS transistors each receiving differential local frequency signal, and a third pair of P-channel MOS transistors receiving differential radio frequency signal. Each pair of transistors is coupled in series with a parallel resonance circuit which operates as a constant current source. A drain of each transistor of the third pair of transistors is connected to a junction of a first pair and a second pair of transistors and a parallel resonance circuit. An output intermediate frequency signal, which differs between the local frequency and the radio frequency, is obtained at the junction of drains of the first and the second pair of transistors and load resistors.

Abstract: An optical amplifier includes an erbium doped fiber of which at least one of a core part and a clad part is doped with erbium, excitation light sources or exciting the optical fiber, optical means for inputting excitation light from the excitation light source and signal light to the Er-doped fiber, and an optical isolator. The erbium doped fiber is a 1.58 &mgr;m band optical fiber having an equivalent fiber length as a product of a fiber length (m) and an erbium doping concentration (ppm by weight), which length provides a signal gain obtained at a wavelength of the excitation light source used for excitation of the erbium doped fiber of more than a predetermined practical reference value.

Abstract: There is provided an optical-fiber; and a cylinder body which is made from a cylindrically formed belt-shaped material and made of resin and which accommodates the optical-fiber therein.

Abstract: The invention is directed to an optical connector in which a length of an optical fiber 5 projects from a connection end surface (16) of a ferrule (1) is accurately set, a method of and a fixture for setting the projection length of the optical fiber. A recess surface (33) is formed in a ferrule receiving surface (32). A depth of the recess surface (33) is equal to a length an optical fiber (5) projects from the connection end surface (16) of the ferrule (1). The ferrule (1) is held by ferrule holding members (35a) and (35b), so that the ferrule (1) is abutted against the ferrule receiving surface (32) by the urging force of compression springs (36). Through the ferrule (1), an optical fiber cored line (3) is projected from the connection end surface (16) of the ferrule (1) and abutted against the recess surface (33).

Abstract: A data communication protocol is implemented to control data flow between a transport layer and a data link layer. The protocol provides two manners of data flow control. (1) In the first control manner, when the occupancy of packet buffers of the data link layer is smaller than a first threshold, the data link layer informs of the transport layer that the packet transport should be suspended, and thereafter when the occupancy is smaller than a second threshold smaller than the first one, the data link layer requests the transport layer to resume the packet transfer. (2) In the second control manner, when the amount of packets is smaller than a value determined based on the transfer rate and maximum burst size, the transport layer transfers a packet to a lower layer, and when the packet amount is larger than the value, a packet is transferred after a predetermined time passes to control the transfer rate to a predetermined one.

Abstract: An electro-optic sampling oscilloscope (or EOS oscilloscope) is designed to perform measurement such that an electro-optic sampling probe (i.e., EOS probe) is brought into contact with a measured circuit. Optical pulses are input to the EOS probe, wherein they are varied in polarization states in response to the measured circuit. Then, an electric signal output from the EOS probe is amplified to produce a receiving light signal. The receiving light signal is subjected to sampling operations using a first pulse signal to produce detection data, while it is also subjected to sampling operations using a second pulse signal to produce noise data. Herein, the first pulse signal consists of pulses which emerge in synchronization with the optical pulses respectively, while the second pulse signal delays from the first pulse signal by a prescribed delay time. Then, measurement data are produced by subtracting the noise data from the detection data.