Abstract: The network failure detection apparatus is realized as a function of a terminal in a network. The network failure detection apparatus acquires packet reception statistic information on a port-by-port basis of a relay unit, and extracts a port having a large amount of packet reception per unit time. When there is one port having a large reception amount in a certain relay unit, the network failure detection apparatus decides that the L2 (layer 2) loop is occurred in the downstream direction of the port concerned. Also, when there are two ports having a large reception amount in a certain relay unit, the network failure detection apparatus decides that a loop is formed at the relevant two ports, in which the L2 loop is occurred.

Abstract: A small-scale wireless communication system offering advanced security level. An encryption key memory of an access point stores an encryption key list of a plurality of different encryption keys. A change information transmitter periodically transmits change information to a terminal by radio, the change information requesting the change of encryption key. An encryption key selector selects an encryption key from the encryption key list under a rule when the change information transmitter transmits the change information. A terminal-side encryption key memory of the terminal stores a terminal-side encryption key list which is the same as the encryption key list. A change information receiver receives the change information from the access point. Upon reception of the change information, a terminal-side encryption key selector selects an encryption key from the terminal-side encryption key list under a rule which is the same as the rule which the encryption key selector used to select the encryption key.

Abstract: A transmitter-side access point measures a transmission delay between the transmitter-side access point and a receiver-side access point, and calculates a threshold based on the transmission delay. Unless the amount of data from a source user terminal exceeds the threshold, the transmitter-side access point transmits data over a network in response to a request from the receiver-side access point. When the amount of data from the source user terminal exceeds the threshold, the data is transported as being stored in a physical medium to the receiver-side access point through transportation service. The receiver-side access point obtains the data from the transported physical medium, and transfers the data to a destination user terminal.

Abstract: In a relay device or the like in which a speed changes from a high speed to a low speed, a packet residence (packet transfer wait) occurs when a packet string in which packet intervals are shortened arrives. When a packet discard occurs before passing through the relay device or the like, a packet interval having been lengthened by the packet discard is shortened by the relay device or the like for transferring packets. When a packet discard occurs after passing through the relay device or the like, a packet interval having been lengthened by the packet discard remains unshortened for transferring packets. Therefore, by observing at terminals the packet discard and the packet interval on the occasion of the packet discard, whether the packet discard has occurred in the high speed section or the low speed section is specified.

Abstract: The invention provides a gas supply device designed to supply a combustion preventing gas (mixed gas) in which a cover gas for suppressing combustion of molten magnesium held in a melting furnace and a diluting gas for diluting the cover gas are mixed with each other, the gas supply device including a carbon monoxide concentration meter for detecting combustion of a molten metal. The gas supply device further includes a gas introduction device for supplying the combustion preventing gas to the melting furnace in case it is determined that combustion of a molten metal is present, and halts supply of the combustion preventing gas to the melting furnace in case it is determined that combustion of a molten metal is absent.

Abstract: Communication quality values such as delay times of packets transmitted and received within a packet network are measured, and a threshold value is calculated based on the measured communication quality values. Further, a management reference value is calculated based on the communication quality values of packets whose measured communication quality values are within a range based on the threshold value. A communication state is detected by comparing the measured communication quality values with the management reference value.

Abstract: In order to provide a method for supplying a cover gas which has sufficient preventive effects of oxidation-combustion and prevents cost-increase by containing a necessary and sufficient amount of fluoroketone in the cover gas which is supplied in a melting furnace of magnesium, the present invention provides a method for supplying a cover gas containing fluoroketone in a melt furnace to prevent oxidation and combustion of a melt of magnesium in the melt furnace, wherein the moisture concentration of gas in the melt furnace is measured, and the concentration of fluoroketone in the cover gas is adjusted to a range from 1/50 to 1/5 relative to the moisture concentration.

Abstract: A request-packet transmitting unit transmits a predetermined number of request packets having a non-unicast destination address that can be received by a target network including a network identified by a first network address, from a monitoring network identified by a second network address different from the first network address through a layer 3 relay device. A layer 2 loop detecting unit receives response packets corresponding to transmitted request packets through the layer 3 relay device, and detects a layer 2 loop in the target network based on number of received response packets and number of transmitted request packets.

Abstract: A radio communication system for leveling off the processing loads of radio stations (access points) to which mobile terminals are connected, to improve the quality of service in radio communication. A mobile terminal searches for a beacon signal and transmits a connection request to a radio station which has sent the beacon signal captured. In the access point, a beacon-signal transmission section transmits the beacon signal, a connection-count management section manages, according to a connection-completion message, a local-station connection count and an other-station connection count, and a connection processing section receives the connection request, performs comparison processing for the local-station connection count and the other-station connection count, applies, when the local-station connection count is smaller than the other-station connection count, connection processing to the mobile terminal and generates a connection-completion message when a connection to the mobile terminal is completed.

Abstract: A traffic management system manages, distributes, and controls various traveling states of vehicles at a high quality level. A vehicle-mounted unit performs an interconnection process for user authentication when entering a predetermined radio-wave zone. A radio unit disposed on a road sends interconnection process completion information to a center device when the interconnection process for connection to the vehicle is completed. If the vehicle does not connect to the radio unit after elapsed of a predicted time at which the vehicle is expected to travel across the radio unit, then the radio unit sends an overtime to the center device. The interconnection process completion information is received, the center device calculates a predicted time at which the vehicle is expected to pass across a radio unit, and sends the predicted time to the radio unit. When the overtime is received, the center device determines whether a fault has occurred or not.

Abstract: An object of the present invention is to provide a melting method for magnesium or a magnesium alloy which detects certainly and immediately combustion of a magnesium melt and emits alarm immediately based on the detection results, and extinguishes immediately the magnesium combustion, in order to achieve the object, the present invention provide a method for melting magnesium while supplying a cover gas containing carbon dioxide and a fireproof agent in a furnace for melting magnesium and obtaining a magnesium melt to cover the surface of the magnesium melt, wherein concentration of carbon monoxide in the furnace or gas discharged from the furnace is measured and magnesium combustion in the furnace is detected based on the concentration of carbon monoxide.

Abstract: A packet reception portion receives packets of user traffic transferred on the network. The received packets are transferred to an address extraction portion via a distribution portion, and the transmission source address and destination address are extracted. Based on these addresses, a packet generation portion generates probe packets the transfer destination of which is the address destination. A packet transmission portion transmits the probe packets to the network. The transmitted probe packets are received as probe response packets by the packet reception portion. The probe response packets received by the packet reception portion are transferred to a result storage portion via the distribution portion. The result storage portion stores transmission source addresses included in the probe packets in a result storage DB.

Abstract: When a server RM detects a failure in an operating server, a system resource manager selects a substitute server from a pool of a server domain to which a failed server belongs, based on information in a system resource DB, disconnects the failed server from a business network and a storage sub group and moves the failed server to a pool, and permits the substitute server to access a storage group to which the failed server had an access and to connect to the business network to which the failed server was connected, to boot up the substitute server from a SAN.

Abstract: A wireless communication apparatus capable of preventing data leakage in wireless communication. A transmitted data frame receiver receives a transmitted data frame which is transmitted from a terminal to the wireless communication apparatus. An address information converter converts the address information of the terminal included in the transmitted data frame, into the address information of the own wireless communication apparatus. A radio transmitter transmits the transmitted data frame by radio. An address information comparator compares the address information included in a received data frame received by a radio receiver, with the address information of wireless communication apparatuses being stored in an address information memory. A received data frame destruction unit destructs the received data frame depending on the comparison result.

Abstract: A communication conditions determination method, a communication conditions determination system, and a determination apparatus are provided in which the conditions of communication which is performed through a plurality of communication networks are determined without setting up a special apparatus on all the communication networks and without increasing the existing traffic. In a first communication network 100 and a second communication network 200 which are connected by a first connection apparatus 1 such as a router, a determination is made as to whether the source of a packet passed through the second communication network 200 is the first connection apparatus 1 or an apparatus other than the first connection apparatus 1. Packets whose respective sources are the first connection apparatus 1 and packets whose respective sources are an apparatus other than the first connection apparatus 1 are individually summarized. By comparing summarized results, the communication conditions are determined.

Abstract: A L2 loop failure location generated in any one of a plurality of search target apparatuses disposed in network is detected in a short time. A network failure location detecting apparatus executes the steps of broadcasting packets with a plurality of different source MAC addresses; acquiring statistical information that is information of a learning port of the plurality of different source MAC addresses learned by each of the plurality of search target apparatuses; finding whether the number of the learning ports of the plurality of different source MAC addresses is one or two from the acquired statistical information; and determining that the L2 loop failure location is the search target apparatus including two learning ports of the plurality of different source MAC addresses.

Abstract: A network fault detection apparatus, which detects L2 loops due to L3 bridge connections, is provided. A network fault detection apparatus acquires physical addresses corresponding to the network addresses of at least two nodes among the plurality of nodes constituting a network, and by detecting the existence of a plurality of physical addresses for network addresses of the two nodes, and detecting the existence of a physical address common to network addresses thereamong, detects an L2 loop caused by an L3 bridge connection, which induces a network fault.

Abstract: An IP packet relay apparatus provided between networks to relay an IP packet relating to a host belonging to a specific group, comprising: a list in which an IP address possessed by a host is associated with a group identifier for identifying a group to which the host belongs; a judgment unit judging whether an IP packet that has received from one network and is addressed to a host connected to another network is an IP packet relating to the same group or not with reference to the list; and a forwarding unit relaying an IP packet judged to be the IP packet relating to the same group.

Abstract: A computer-readable recording medium recording a program capable of accurately analyzing the cause of a performance fault at the very end point of a client system, server system, etc. Outgoing and incoming packets are captured during execution of a communication application to measure a round trip time, and a communication window size of the transmitting source is estimated based on the captured incoming packets. A throughput estimate is calculated from the round trip time and the communication window size, and the estimated value and actual measured value of the throughput are displayed on, for example, a display, together with various other communication parameters including the communication window size and the round trip time, whereby the cause of a performance fault can be accurately located by quantitative analysis.

Abstract: A communication control device constitutes an access point of a wireless LAN system. The communication control device includes a unit receiving a movement advance notification of a terminal into a wireless zone under control; and a unit transmitting a transmission standby instruction so that a terminal transmitting data is brought into a wait state and a movement target terminal moving into the wireless zone under the control is allowed to transmit data by priority upon reception of the movement advance notification.