Abstract: An electronic device includes: a communication device configured to communicate with a server device that provides data; a storage device; and a control device that cyclically accesses the server device using the communication device to check whether or not new data has been provided from the server device, determines, based on a predetermined probability, whether to download the new data from the server device or to postpone download when the new data has been provided, and stores, in the storage device, the new data downloaded from the server device.

Abstract: An azimuth estimation device includes a satellite data acquisition unit that acquires Doppler shift frequencies of navigation signals, a sensor data acquisition unit that acquires a yaw rate from a yaw rate sensor, a Doppler azimuth estimation unit that estimates an azimuth of a moving object, a state variable determination unit that determines a state variable indicating reliability of an azimuth angle, a threshold selection unit that selects, from plural evaluation parameter threshold groups for determining whether to adopt the azimuth as a reference azimuth, one of the evaluation parameter threshold groups, an evaluation parameter calculation unit that calculates plural evaluation parameters for evaluating reliability of an azimuth, and an adopting determination unit that compares the plural evaluation parameters with the evaluation parameter threshold group, and based on determination that an adopting condition is satisfied, determines adoption of the azimuth as the reference azimuth.

Abstract: A positioning device or a speed measuring device includes: a satellite information acquisition portion that acquires satellite information including information related to a position of multiple satellites and information related to a distance between each of the multiple satellites and a mobile body or a relative speed with the multiple satellites; an attitude detection portion that detects an attitude of the mobile body; a relationship calculation portion that calculates a positional relationship or a speed relationship between an installation location of each of the multiple satellite antennas on the earth and a positioning target location; and a calculation portion that calculates a position of the positioning target location on the earth or a speed at the positioning target location.

Abstract: A positioning device includes a satellite positioning unit, an autonomous positioning unit and an error estimation unit. The satellite positioning unit acquires a position of a moving object determined by satellite navigation based on navigation signals. The autonomous positioning unit estimates a movement trajectory of the moving object based on satellite information, which is information before the position of the moving object is calculated in the satellite navigation and detection values of behavior detection sensors, and estimates the position of the moving object based on a reference point and the movement trajectory of the moving object.

Abstract: A positioning apparatus includes: a satellite positioning device calculating a satellite positioning coordinate based on a navigation signal received by a navigation signal receiver; a movement quantity calculator acquiring a signal from an inertial sensor and sequentially calculating a movement quantity of the movable object by inertial navigation from receiving a navigation signal until receiving the signal from the inertial sensor; a virtual reference point determinator sequentially determining a virtual reference point after receiving the navigation signal; and a position determinator determining the position of the movable object sequentially based on the movement quantity of the movable object from the virtual reference point.

Abstract: An azimuth estimation device includes a satellite data acquisition unit that acquires Doppler shift frequencies of navigation signals, a sensor data acquisition unit that acquires a yaw rate from a yaw rate sensor, a Doppler azimuth estimation unit that estimates an azimuth of a moving object, a state variable determination unit that determines a state variable indicating reliability of an azimuth angle, a threshold selection unit that selects, from plural evaluation parameter threshold groups for determining whether to adopt the azimuth as a reference azimuth, one of the evaluation parameter threshold groups, an evaluation parameter calculation unit that calculates plural evaluation parameters for evaluating reliability of an azimuth, and an adopting determination unit that compares the plural evaluation parameters with the evaluation parameter threshold group, and based on determination that an adopting condition is satisfied, determines adoption of the azimuth as the reference azimuth.

Abstract: A positioning device includes a satellite positioning unit, an autonomous positioning unit and an error estimation unit. The satellite positioning unit acquires a position of a moving object determined by satellite navigation based on navigation signals. The autonomous positioning unit estimates a movement trajectory of the moving object based on satellite information, which is information before the position of the moving object is calculated in the satellite navigation and detection values of behavior detection sensors, and estimates the position of the moving object based on a reference point and the movement trajectory of the moving object.

Abstract: A positioning apparatus includes: a satellite positioning device calculating a satellite positioning coordinate based on a navigation signal received by a navigation signal receiver; a movement quantity calculator acquiring a signal from an inertial sensor and sequentially calculating a movement quantity of the movable object by inertial navigation from receiving a navigation signal until receiving the signal from the inertial sensor; a virtual reference point determinator sequentially determining a virtual reference point after receiving the navigation signal; and a position determinator determining the position of the movable object sequentially based on the movement quantity of the movable object from the virtual reference point.

Abstract: A VPN device capable of eliminating situations where cross calls occur is provided. The VPN device includes: an identification information acquisition unit that acquires first identification information which is identification information of a communication terminal (103) and second identification information which is identification information of a communication terminal (303); a priority determination unit that determines the priority for initiating a session between the communication terminal (103) and the communication terminal (303) based on the first and second identification information; a message type generation unit that designates the type of a message relating to call control to be transmitted to the communication terminal (303) based on the priority; and a transmission unit that transmits a message of the designated type to the communication terminal (303).

Abstract: An ENUM system includes a Web server and an ENUM server. The Web server stores first NAPTR records corresponding to an ENUM client and another ENUM client on an IP network. The ENUM server stores second NAPTR records in which first URIs are associated with predetermined information for being linked to the Web server. In the ENUM system, the ENUM client transmits, to the ENUM server, a query for the second NAPTR record of the another ENUM client. The ENUM client then transmits, to the Web server, a request for access to the first URI included in the received second NAPTR record, and obtains the first NAPTR record corresponding to the another ENUM client.

Abstract: An IP terminal apparatus has a SIP controller, a UDP packet controller, and an RTP controller. The SIP controller transmits and receives a call control message in order to establish a connection to and from a destination apparatus. The UDP packet controller transmits and receives media data with the destination apparatus in a media session after the connection was established. The RTP controller obtains source port number information of a media data packet that the UDP packet controller has received from the destination apparatus, and sets the obtained source port number as a destination port number for a packet to be transmitted to the destination apparatus. Thereby, a feasible range of NAT traversal can be improved in a simple and secure manner, even when at least one relay apparatuses employs symmetric NAT.

Abstract: An IP telephone system includes a source IP telephone apparatus, a Web server and an ENUM server. The source IP telephone apparatus is connected to an IP network. The Web server stores predetermined information regarding a user of the source IP telephone apparatus and transmits, to a destination IP telephone apparatus, the predetermined information in response to a request from the destination IP telephone apparatus. The ENUM server stores a NAPTR resource record which includes a URI utilized for obtaining the predetermined information stored in the Web server. In the IP telephone system, the destination IP telephone apparatus transmits, to the ENUM server, a request for a NAPTR resource record of the source IP telephone apparatus and transmits, to the Web server, a request for the predetermined information regarding the source IP telephone apparatus according to the obtained NAPTR resource record.

Abstract: An IP telephone apparatus is connected to an ENUM server and a Web server via an IP network. The ENUM server has a database that stores an IP telephone URI as terminal information of the IP telephone apparatus and a Web server URI corresponding to the IP telephone apparatus. The Web server stores image data captured by a camera. The IP telephone apparatus transmits to the ENUM server a query on terminal information of a destination IP telephone apparatus; receives from the ENUM server the terminal information of the destination IP telephone apparatus; acquires from the received terminal information a Web server URI corresponding to the destination IP telephone apparatus and performs visual communication with the Web server based on the Web server URI; and displays captured image data received from the Web server in the visual communication.

Abstract: In a networking method of a communication apparatus in which global address information and port information are acquired on a network, a virtual private network is established with another communication apparatus using the global address information and the port information to perform the communication, the networking method includes determining whether communication data that is transmitted from the communication apparatus is a first protocol or a second protocol, and starting a data transmission through the network before the virtual private network is established when the communication apparatus determines that the communication data is the first protocol, and starting a data transmission after the virtual private network is established when the communication apparatus determines that the communication data is the second protocol.

Abstract: An IP telephone system comprises an IP telephone that performs voice communication via an IP network, a carrier that manages voice communication for the IP telephone via the IP network and a server that returns NAPTR resource record(s) in response to a request from the IP telephone. In the IP telephone system, when the IP telephone performs voice communication via the IP network, the IP telephone transmits, to the server, a request for NAPTR resource record(s) that correspond(s) to the telephone number of the destination terminal. When NAPTR resource record(s) is(are) stored, voice communication is directly performed between the IP telephone and the destination terminal via the IP network according to the NAPTR resource record. On the other hand, when NAPTR resource record(s) is(are) not stored, the carrier manages calls, and voice communication is performed between the IP telephone and the destination terminal via the IP network.

Abstract: An ENUM server stores NAPTR records including PSTN telephone numbers and the corresponding IP telephone numbers of a source IP telephone apparatus and a destination IP telephone apparatus. When the ENUM server receives an ENUM query from the source IP telephone apparatus, the ENUM query setting a domain name based on the PSTN telephone number, the ENUM server searches for a NAPTR record corresponding to the domain name and returns, to the source IP telephone apparatus, an ENUM response including the NAPTR record. When receiving the ENUM response from the ENUM server, the source IP telephone apparatus retrieves the IP telephone number of the destination IP telephone apparatus, the IP telephone number being specified in the NAPTR record contained in the ENUM response, and starts a call connection sequence with the destination IP telephone apparatus.

Abstract: An IP telephone number query system includes a terminal, a Web server, and an ENUM server. The terminal displays a call recipient profile hypertext markup language (html) that is assigned a HTML document file name. The Web server includes a phonebook searcher that has a plurality of call recipient profile htmls, and returns a selected call recipient profile html in response to a request from the terminal. The ENUM server has a database, a query issuer and a reversed query issuer. The database stores a plurality of NAPTR resource records in association with an ENUM domain name, each NAPTR resource record containing a URI that at least includes a telephone number and a HTML document file name. The query issuer searches the database in response to a query by an ENUM domain name and returns a NAPTR resource record corresponding to the ENUM domain name.

Abstract: A source IP telephone inputs, from its numeric keypad, a telephone number of a call destination and obtains, from an ENUM server, a NAPTR record of the destination IP telephone based upon the input telephone number of the call destination. By referring to a search table, the source IP telephone retrieves, from the obtained NAPTR record, an available specific number in the ascending order of call rates from the lowest based upon communication services available to the source IP telephone. The source IP telephone transmits a call to the destination IP telephone by using the retrieved specific number.

Abstract: An internal terminal that connects to a DNS server, the server storing and managing a telephone number for communication and an external NAPTR record, the internal terminal including: a terminal communication controller that accesses the DNS server and notifies the DNS server of a telephone number for the communication; a terminal-side controller that obtains, when the DNS server is informed of the communication telephone number, an external NAPTR record being corresponding to the communication telephone number; an IP service presence determination unit that determines whether the external NAPTR record has function service information related to IP communication; and a display that displays the available IP communication service function of the destination corresponding to the communication telephone number, when it is determined that the external NAPTR record has the IP communication service function.

Abstract: In a NAT type determination method pursuant to RFC 3489, address information added in a binding response from a STUN server in response to a binding request issued in a latest transmission test is compared with address information added in a binding response in response to any transmission test executed therebefore. When the address information are not identical, a NAT type is determined symmetric. Even when a router whose NAT type changes frequently according to a use status is connected, communication is capable without manual setting change by a user.