Abstract: A method for acquiring positional information on a wireless terminal station set to its power-saving mode. The access point uses stored-data information in a beacon frame to inform the station applied with the power-saving mode of the presence of stored data regardless of whether or not the stored data exists. The station involved in its dose condition will enter its awake condition immediately before the beacon frame timing to receive a beacon frame. The station then checks the stored-data information and transmits a stored-data request frame to the access point. The access point transmits a data frame if stored data exists, or transmits a null frame if no data is stored. If no stored-data request frame is received within a predetermined time period, the access point determines that the station has moved out of its service area, cancels the registration of the station, and deletes the stored data, if any.

Abstract: A handover method is to provided by which a station can move between access points with interruption in communication minimized. An access point assigns mobile stations existing in its own wireless network to identification codes, different from station to station, to thereby carry out association, and thereafter transmits beacon frames each containing a different identification code to the mobile stations. The identification codes are allocated beforehand specifically to each of the access points included in the wireless LAN. When the station is handed over to an adjacent access point, the adjacent access point transmits beacon frames containing the corresponding identification code to that station. Thus, the station is able to continue communication without recognizing the transfer from one wireless network to another.

Abstract: An access point is provided which is able to secure QoS of multimedia traffic. In the method of controlling QoS for wireless LAN base station apparatus used in a wireless LAN system operating in accordance with IEEE 802.11 standard, the base station or access point is included in a network working in an infrastructure mode with other mobile stations controlled in access by the DCF function. When the access point is receiving a first frame sent from the mobile station and holds a multimedia frame to be sent with high-priority after having received the first frame, it loads the Duration/ID field of an ACK frame responding to the first frame with a time required for transmitting the multimedia frame, and then sends the ACK frame.

Abstract: An SDH transmission apparatus including a low-speed part, a high-speed part, and a cross-connect part is disclosed. The low speed part includes a first signal transmission part and a second signal transmission part, each signal transmission part including an active transmission part and a standby transmission part. In the SDH transmission apparatus, an active transmission part of the first signal transmission part transmits a signal to a first transmission line via the high-speed part, an active transmission part of the second signal transmission part transmits a signal to a second transmission line via the high-speed part, and a standby transmission part of the first signal transmission part sends a part of signals supplied to the first signal transmission part to the second transmission line via the high-speed part when a traffic amount of the signals supplied to the first signal transmission part exceed a predetermined value.

Abstract: A radio apparatus applicable to an IBSS (Independent Basic Service Set) network includes a timing generator for generating a timing signal in accordance with the phase of a received frame. A decision circuitry acquires the source address of the received frame in response to the timing signal and received frame, and determines the type of the received frame and whether or not the received frame is addressed to the radio apparatus and correctly received. A registrar acquires information representative of the processing capability of a source from the received frame in accordance with the timing signal, signals output from the decision circuitry and source address and registers the above information and source address. A canceller determines withdrawal from an IBSS area in response to the timing signal, signals output from said decision circuitry, source address and particular information relating to the type of the received frame.

Abstract: A wireless communication apparatus coordinates communication among a set of mobile stations by giving the mobile stations permission to transmit packets. The mobile stations divide comparatively long packets into shorter fragment packets. When the wireless communication apparatus receives a fragment packet with an indication that the station that transmitted the fragment packet has another fragment packet to transmit, the wireless communication apparatus gives the mobile station permission to transmit the next packet. The mobile station can accordingly transmit its fragment packets in continuous succession, avoiding a defragmentation timeout at the receiving end.

Abstract: A communication apparatus installed in the trains and that in a complex station building, a station or a maintenance factory communication through feeders, trolley wires or third rails can communicate each other. The present invention can realize a low cost vehicle-facility intra communication system that provides various information services available in the train.

Abstract: A trigger state in a cell delay variation absorbing apparatus is set. A value of (a sequence number of a reception packet+1) is inputted from a UUI code holding unit (3) to a reception counter (1). When a state where a call has been set is obtained by a calling setting (115), a counter trigger generating unit (11) generates a counter trigger. When the counter trigger is received, the reception counter starts to count up from the sequence number received from the UUI code holding unit. Thus, the reception counter can be synchronized with the sequence number of the reception packet which is received subsequently.

Abstract: The present invention provides a method and apparatus for moving a head arm assembly to a landing zone in a disk drive storage device. In disk drive according to the present invention, a control means responds to termination of a read/write operation by applying a drive current for moving an actuator arm toward an actuator lock, and then continuously applies the drive current to the actuating means to maintain an engagement of the actuator arm with the actuator lock stopped at a predetermined position, after the termination of read/write operation, and then stops a rotation of said rotating data recording disk.

Abstract: A reduced height disk drive includes a suspension-actuator assembly in which a head suspension (10) is attached to an actuator (9) on the same side of the head suspension as a transducer head (8) is attached to the head suspension for writing and reading information on and from a disk (7). A spin motor cable (17) is located on the outside of a housing (2) and connected to pins (14) extending from the housing through pins (18) extending from the housing and lines (16) contained in the housing. A printed circuit board (3) having a through hole (3e) in which a connector (13) is provided connects to pins (14) extending from the housing. A flexible printed circuit inside the housing has a connector (11k) for connecting to the pins (14) and (18) at one end and a fixing member for mechanically attaching to the pins at the other end. The flexible printed circuit is attached to the pins in a folded condition.

Abstract: A vacuum circuit breaker particularly suitable for use in an electric motor vehicle. The circuit breaker includes a vacuum interrupter to which a voltage is applied, the series combination of a capacitor and a switch which are connected in parallel with the vacuum interrupter, a provision for charging the capacitor with a voltage opposite the voltage applied to the vacuum interrupter, and a resistance connected in parallel with the vacuum interrupter. The vacuum interrupter, the resistance, and the series combination of the capacitor and switch form oscillation circuit having an oscillation frequency at least 2 KHz and an inductance of at least 1 .mu.H, with a commutating current of at least 5000 A for consuming energy stored in the circuit.

Abstract: A cushioning material is disclosed which includes two laminated films between which a plurality of air tight cells are formed. Each of the films is composed of an intermediate layer formed of an aromatic polyamide resin and two surface layers formed of a polyolefin resin and provided on both sides of the intermediate layer, wherein the aromatic polyamide resin is one obtained by polycondensing m-xylylenediamine with an aliphatic dicarboxylic acid selected from the group consisting of adipic acid, terephthalic acid, isophthalic acid and mixtures thereof, and the polyolefin resin is a member selected from the group consisting of low density polyethylenes, ethylene/.alpha.-olefin copolymers and mixtures thereof.

Abstract: Prefoamed particles of a polyolefin resin are produced by dispersing starting particles of the polyolefin resin, which contains a volatile foaming agent, in a dispersant in a pressure vessel, heating the resultant dispersion to a temperature of at least the softening point of the starting particles in said pressure vessel and then opening the vessel at one end thereof so as to release the starting particles and dispersant into an atmosphere of a pressure lower than the internal pressure of the vessel. The release of the starting particles and dispersant is performed while feeding a heating liquid.

Abstract: Method of producing a molded article of a foamed thermoplastic resin. A molten mass of an expandable thermoplastic resin is accumulated in an accumulator while it is prevented from foaming. A predetermined quantity of the accumulated thermoplastic resin is ejected rapidly from the accumulator into the atmosphere so that the thermoplastic resin commences foaming. The ejected thermoplastic resin is placed in a mold cavity before the foaming expansion has been completed and is compressed. The expansion and molding of the ejected thermoplastic resin is completed in the mold while controlling the compression pressure to obtain a foamed molded article.

Abstract: Pre-foamed particles are produced by dispersing resin particles, which contain nucleocells, in a dispersing medium in a closed vessel, heating the contents to a temperature of the softening point of the particles or higher and holding the contents at the temperature for a predetermined period of time while pressurizing the contents with an inorganic gas, and then opening the vessel at one end thereof so as to release the particles and medium into an atmosphere of a pressure lower than the internal pressure of the vessel, thereby causing the resin particles to foam. The above production process provides good pre-foamed particles with ease and without failure. It is also possible to avoid deleterious effects due to the swelling action of foaming agents.

Abstract: An apparatus is provided for the heat treatment of polyolefin resin particles. The apparatus is equipped with an autoclave in which the particles are heated and agitated in the presence of an aqueous medium and dispersing agent. The autoclave has a tilted bottom wall portion, over which an impeller, preferably, a turbine-type impeller is provided.

Abstract: Propylene-base random copolymer particles suitable for use in the production of pre-foamed particles are obtained by heating starting copolymer particles of ethylene-propylene random copolymer to the crystallization temperature thereof and then quenching them in a medium at a temperature of (the crystallization temperature-30.degree. C.) or lower. Pre-foamed particles produced using the copolymer particles contain large cells are columnar in shape with an average diameter D of 1.7 mm or less and an L/D.gtoreq.1. They can thus provide foamed moldings which are substantially free of shrinkage and have good flexibility.

Abstract: Disclosed herein are propylene-base random copolymer particles suitable for use in the production of pre-foamed particles. The copolymer particles are obtained by heating starting copolymer particles to the crystallization temperature thereof and then quenching them in a medium of (the crystallization temperature-30.degree. C.) or lower. Processes for obtaining the copolymer particles are also disclosed. Pre-foamed particles produced using the copolymer particles contain large cells. They can thus provide foamed moldings which are substantially free of shrinkage and have good flexibility.

Abstract: There is provided a logic device wherein an alternating input signal having a frequency which is one of two frequencies allotted to two input logical values, respectively, positive logic "1" and negative logic "0", is inputted to the device. An output logical value is decided depending on the determination which frequencies the input frequency coincides with or not, and an alternating output signal having a frequency which corresponds to the output logical value is delivered out of the device. The logic device, even when constituted with semiconductor elements, can have highly reliable fail-safe capability and can be reduced in size and weight.

Abstract: This invention provides an electrical conductive foam bead comprising a foamed bead core of a thermoplastic synthetic resin at least partially covered on the surface thereof with an electrical conductive layer, and a molded electrical conductive foamed article comprising a plurality of particulate bodies formed by mutually fusing such electrical conductive foam beads, the electrical conductive layers extending over all or a portion of the interface of the mutually fused particulate bodies. The conductive foam beads and molded conductive foamed articles both have improved antistatic effect and are used as packaging and cushioning materials, electromagnetic radiation shields, and the like.