KR101006920B1 - Method for Discovering Universal Services in Sub-networks - Google Patents

Abstract

The present invention relates to a method for reflecting service dynamic state of a subnetwork in a ubiquitous environment, and more particularly, includes an adapter, a registration agent, a device / service registry, a context registry, and a UDDI, wherein (A) the adapter includes: Collecting specification information and dynamic state information of devices and services of each subnetwork, delivering the registration information to a registration agent, converting the services of the subnetwork into a virtual web service, and delivering the registration agent to the registration agent ; (B) the registration agent stores the specification information and the dynamic state information received from the adapter in the device / service registry, context registry, and UDDI registry , respectively; The present invention relates to a method for reflecting service dynamic state of a subnetwork in ubiquitous.

Ubiquitous, Device, Subnetwork, Service, Dynamic State

Description

How to reflect service dynamic state of subnetworks {Method for Discovering Universal Services in Sub-networks}

The present invention relates to a method for reflecting service dynamic state of a subnetwork in a ubiquitous environment.

In a ubiquitous environment, any service from any device on any network must be available anytime, anywhere. Currently, service discovery technologies in the ubiquitous environment include Java Intelligent Network Infrastructure (Jini), Universal Plug and Play (UPnP), Device Profile for Web Services (DPWS), and Home Audio Video interoperability (HAVi). They allow users to discover only services with their own communication protocols and running environment. The user must also follow each communication protocol and have a driving environment. In order to realize ubiquitous in such environment, we need a service discovery method that can discover services dynamically.

The service discovery method required in the ubiquitous environment should have different features from the existing service discovery method. This method of service discovery should not only reflect the characteristics of each network, but also take into account the dynamics present in ubiquitous environments. Dynamic factors (dynamic state) in the ubiquitous environment include service and user location changes and service state changes. In addition, users and services should be free from communication protocols and operating environments.

The service discovery technologies used in the ubiquitous environment include Jini, UPnP, DPWS, and HAVi, and the web service discovery technologies include WS-Discovery.

The Jini system consists of a client, a service provider, and a lookup service, and consists of three parties' mutual communication. The core of the Jini service structure is the discovery, join, and lookup protocols. The discovery protocol is a process in which a service or a client searches for a lookup service on a network. The service searches for a lookup service to register itself and a client to use the registered service. Joining is the process of joining the Jini community after the service object is located in the lookup service. The lookup protocol is a process in which a client or a user obtains a desired service through a lookup service.

Clients included in the Jini community must go through the following process in order to use the service. The service provider discovers a lookup service through a multicast request on the local network and registers a service object and a service attribute with the lookup service. The service object contains a Java programming interface for the service with a way to start running the service. When a client requests a service based on a Java type or an attribute of a service, a copy of the service object is moved to the client. Thereafter, communication between the client and the service provider takes place.

UPnP is a middleware that provides an operating system, language, and hardware independent service environment in a home networking environment with various media and multiple vendors. The simple, flexible, standards-based peer-to-peer approach provides connectivity. This allows the user to simply connect the device to the network, and existing devices connected to the network can automatically discover and control newly added devices or find services of other devices.

UPnP uses the Simple Service Discovery Protocol (SSDP) for service discovery. SSDP is a protocol similar to Jini's discovery, join, and lookup protocols that is used to inform other devices of their presence or to discover other devices and services. If a newly added device on the network sends a multicast message to the control point to announce its service, then the device becomes a potential client of the services. On the other hand, when a new control point is added on the network, SSDP sends a multicast message for discovery and devices on the network that receive the message send a unicast response.

DPWS is the next generation of UPnP. Therefore, it provides peer-to-peer communication method similarly to UPnP. However, DPWS aims to discover web services, which makes use of the WS-Discovery protocol described later.

HAVi is the middleware for home networks and complies with IEEE 1394. IEEE 1394 has been proposed to transmit A / V information, and HAVi has proposed a home network function that brings together IEEE 1394-compliant A / V devices. HAVi also supports hot pluging and Plug and Play using bus reset and node addressing as supported by IEEE 1394.

The existing ubiquitous service discovery technologies discussed above do not communicate and interwork with each other. Therefore, the user must establish an environment for using each service discovery technology in order to discover each service. In addition, they do not consider the dynamic elements that are the ubiquitous service features, namely location information and state information.

It is possible to extend the existing web service discovery protocol so that both web and ubiquitous services can be discovered and used by users. The existing web service discovery technology is WS-Discovery.

WS-Discovery is a protocol for discovering services in a multicast manner. The user will send a message to the multicast specifying the type and scope of the service needed to discover the service. The service that receives the message sends a response message to the user if the service is the corresponding service, or does not respond. After that, the user selects and uses a desired service from the service list that has been answered.

However, WS-Discovery only targets web services, so ubiquitous services cannot be found. This has the disadvantage that the user is not available and is provided to the user up to a list of unsuitable services in a situation where it is impossible to check whether the service is far from the user.

An object of the present invention is to provide an apparatus for dynamic service discovery that can be used in a ubiquitous environment and a method using the same.

The present invention aims to provide a method for enabling a user to discover all available services around him / her in a ubiquitous environment. All available services around the user are all services that are close to the user's location and are immediately available to the user.

The present invention for solving the above problems, provides a method for reflecting the service dynamic state of the sub-network in the ubiquitous environment.

(1) Device for reflecting service dynamic status

An apparatus for performing a method for reflecting service dynamic state of a subnetwork of the present invention includes an adapter, a registration agent, a device / service registry, a context registry, and a UDDI, wherein (A) the adapter is configured to include each subnetwork. Collecting specification information and dynamic state information of a device and a service, and transmitting the same to a registration agent, converting a service of a subnetwork into a virtual web service, and delivering the same to the registration agent to record in the UDDI; (B) The registration agent is configured to store the specification information and dynamic state information received from the adapter in the device / service registry, context registry, and UDDI registry, respectively.

(2) Method for reflecting service dynamic status

The present invention uses the device, wherein (A) ⓐ the adapter receives a message from a device of a newly appeared or changed state of the sub-network collecting the device or service specification information and dynamic state information ⓑ the adapter And checking whether the device or service is registered in the UDDI and the universal registry. © If the device or service is already registered, updating only dynamic state information in the context registry.If the device or service is a new device or service, the adapter is a virtual web service. A process of advancing a sub-network device consisting of converting and transferring the registration agent to the registration agent and newly registering the UDDI, a device / service registry, and a context registry; and (B) Inquiring the device of the network whether or not the service is available ⓑ The adapter registers the connection termination information with respect to the device that the response to the service availability inquiry is not returned for a predetermined time or there is a connection termination (Bye) message. A service dynamic state of a subnetwork in a ubiquitous process, which includes an exiting process of a subnetwork device, wherein the registration agent transmits the connection termination information to the context registry to change state information of the device. It is about a reflection method.

According to the method for dynamic service discovery that can be used in the ubiquitous environment according to the present invention, it is possible to discover a service according to a change in the environment (dynamic state) of a service and a user of a subnetwork, regardless of the driving environment of the service and a communication protocol. Service discovery is possible.

It is possible to discover not only services of many ubiquitous technologies scattered by the present invention but also web services.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. However, these drawings are only examples for easily describing the content and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. In addition, it will be apparent to those skilled in the art that various modifications and changes can be made within the scope of the present invention based on these examples.

1 is a block diagram illustrating an exemplary structure of an apparatus for implementing a method for service dynamic state reflection of a subnetwork of the present invention. The apparatus for reflecting the dynamic state is configured to include an adapter, a registration agent, a query agent, a device / service registry, a context registry, and a UDDI. Their functions are as follows.

(A) Adapter : The adapter plays a role of relay between the subnetwork and the device. As a bridge for communication between heterogeneous subnetworks and devices, universal services are supported by converting the services of the subnetwork into virtual web services.

The subnetwork will deliver its event information to the users of the subnetwork within its area. Thus, the adapter receives the event information of the subnetwork by making it look like a user in the subnetwork.

The adapter has the following functions.

① Message Transfer : It is responsible for transmitting the information necessary for the subnetwork and the device. This is mediated through the adapter because of the heterogeneous communication protocols between the device and the subnetwork.

Sub-network Services Discovery : Converts subnetwork services into virtual web services and retrieves information to be stored in the registry. The retrieved information is sent to the registration agent after the virtual web service is created and stored in the device / service registry, context registry, and UDDI registry.

③ Virtual Web Services Creation : Since the user terminal searches for and uses a service without recognizing the existence of the subnetwork, the service of the subnetwork is converted into a web service type. The converted service is exposed to the user terminal as a virtual web service externally. In this way, the user terminal appears to use Web services, but the services of the subnetwork are actually provided through the universal adapter.

④ Events and Notifications : Supports Plug and Play by reflecting the appearance and exit of subnetwork and devices of subnetwork. In addition, when the user terminal terminates the use of the service, the service state information is changed to enable the service.

⑤ Interoperability with Web Services : It provides the list of services registered in the UDDI registry to the users in the subnetwork and connects them so that they can be used immediately when the user requests the use of web services.

(B) Publish Agent: Register metadata information collected by the adapter in the registry. When metadata information of a device existing in a subnetwork is collected by an adapter, the metadata information is stored in a device / service registry and a context registry, respectively.

(C) Query Agent: When a request is made to register a service from the adapter to check whether the device or service is newly appearing or exiting and reappearing, a service search is performed in the device / service registry using the service ID. Function.

(D) UDDI (Universal Description, Discovery and Integration): Converts, stores and manages all ubiquitous services into web services in order to provide users with usable and close services and to provide not only ubiquitous services but also web services. Ubiquitous service converted into web service is stored and managed in UDDI. At this time, specify whether or not it is a ubiquitous service in business entity. In addition, additional contents of the ubiquitous service that cannot be registered and managed in UDDI can be registered and managed in the registry.

(E) Device / Service Registry: Stores metadata, that is, specification information of devices and services of each subnetwork and specification information of WSUN devices. By doing so, when the service search query of the user terminal is received, the device can not only search for devices and services existing in the subnetwork, but also provide service status information. The device / service registry stores only the common, static, and essential elements of the device and service information of the subnetwork. It is preferable to extract device and service information as shown in Table 1 below.

(F) Context Registry: In the ubiquitous environment, since the location of the device changes frequently, the context registry is used as context information to store the device's state and location information and search for a service that matches the user's state and location information. For example, searching for available printers in a meeting place. This will later be extended to ontology searches such as user terminal profiles.

The device acts as a middleware that supports interoperability of heterogeneous and scattered subnetworks. The apparatus may be located between the service user terminal and the service provider to search for and use services of the subnetwork and services provided by the device.

The device performs the following functions in the process of service discovery, registration and management.

(A) User appearance and dynamic service discovery

The user finds the device using a multicast message to use the device. The device's listener, upon receiving the user's message, communicates to the user the information needed to use the device. The user can then use the device for the services he needs. The user may search for a service by using the service name, description information, and the like. The query agent receiving the service search request searches the UDDI registry and delivers the search result to the user. The list of retrieved services includes both ubiquitous services and existing web services. If the user requires the use of an existing web service, the user supports binding to the existing web service. However, when requesting a ubiquitous service, the user receives information necessary for using the ubiquitous service from the user and connects the service. 2 illustrates a flow of a process of discovering a dynamic service by a user in a system to which the method according to the present invention is applied.

(B) the emergence of ubiquitous networks and services

The advent of ubiquitous networks does not occur in peer-to-peer communication networks. However, in the middleware network that has a service registry like Jini, the service registry is the emergence of ubiquitous network. A flow diagram of the emergence process of ubiquitous networks and services is shown in FIG. 3.

In order to convert a service of a ubiquitous network into a web service, first, a process of obtaining service information is required (1 to 3). The devices in the subnetwork will inform the US broker of their appearance, which is received by the adapter. The adapter receiving the device appearance message requests the subnetwork device for service information necessary for service registration. Upon receiving the service information request message, the subnetwork device sends its detailed information back to the adapter. After this process, a procedure is required to check whether the imported service list has already been converted and stored as a web service (4 ~ 7). To do this, the adapter passes the service ID that appeared to the query agent and requests a service search. The query agent uses the service ID to search the device / service registry for a matching service, and sends a message to the adapter that the service ID, if any, and no search results if none. If the service is already registered, only the service state is converted into a usable state (9-12). If the service is a new service, a web service of the service is created (13) and stored in the UDDI and device / service registry and context registry ( 14-22). Since creating a virtual web service takes a lot of time and cost, it is desirable to create a virtual web service only for a new service. In addition to the service information, the location information of the service and the device is also stored in the context registry to provide a list of services close to the user.

(C) the exit of ubiquitous networks and services;

Ubiquitous network and service exit can be divided into two categories. When a network or service exits and notifies you. In the case of notifying and exiting, the service state may be changed to unavailable (FIG. 4). Later, when the same network and service re-appear, it is good practice to only disable the service state to reduce the cost of creating a virtual web service. On the contrary, in case of an error, if a response message is not received within a predetermined time by sending a message to the service, it is reported that the service is exited and the service state is disabled (FIG. 5).

(D) the emergence of services that support dynamic service discovery methods;

Services that already support the dynamic service discovery method do not need to be converted to Web services. As shown in Fig. 6, in this case, only the case where it is already registered and the case where it is not is judged, and when it is registered, only the state of the service is converted into usable as in the case of the appearance of the ubiquitous network and the service. In the case of a service that is not already registered, the service is registered in UDDI and the universal registry.

(E) Upon expulsion of services that support the dynamic service discovery method.

The exit of a service supporting the dynamic service discovery method is the same as the exit of the ubiquitous subnetwork and service described above. When a service notifies its exit, it will change the state of the service to unavailable (Figure 7).

1 is a block diagram illustrating an exemplary structure of an apparatus for implementing a method for service dynamic state reflection of a subnetwork of the present invention.

2 is a flowchart illustrating a user appearance and service discovery process according to the present invention.

3 is a flow chart showing the appearance of the ubiquitous network and services in the present invention.

4 is a flow chart showing a normal exit process of the ubiquitous network and services in the present invention.

5 is a flowchart illustrating an exit process due to an error of a ubiquitous network and a service in the present invention.

Figure 6 is a flow diagram illustrating the emergence of non-new ubiquitous networks and services in the present invention.

7 is a flow chart showing the emergence of the non-new ubiquitous network and services in the present invention.

Claims (2)

delete Adapter, registration agent, query agent, device / service registry, context registry, and UDDI, wherein (A) the adapter collects specification information and dynamic state information of devices and services of each subnetwork and delivers them to the registration agent. Converting a service of a subnetwork into a virtual web service and recording the same in the UDDI; (B) the registration agent stores the specification information and dynamic state information received from the adapter in the device / service registry and context registry, respectively; As a device for reflecting service dynamic status of a subnetwork, (A) User emergence and service discovery process consisting of the following steps: Ⓐ the user discovers the device and builds a usage environment to use the device Ⓑ A user discovers a web service and a ubiquitous service registered in UDDI through the query agent. Ⓒ If the user selects a web service, connects the web service to the user, and if the user selects the ubiquitous web service, requests additional information from the user and connects the ubiquitous web service according to the information received from the user. (B) Subnetwork device appearance process consisting of the following steps Ⓐ collecting the device or service specification information and dynamic state information by receiving the message from the device of the newly appeared or changed state of the subnetwork The adapter confirms whether the device or service is already registered in the UDDI and the universal registry Ⓒ Updating only dynamic state information in the context registry if the device or service is already registered If a new device or service, the adapter converts the virtual web service to the registration agent and newly registers the UDDI, the device / service registry, and the context registry. (C) the exit process of the subnetwork device consisting of the following steps Ⓐ the adapter inquires whether the devices of the subnetwork are available for service at predetermined time intervals; The adapter sends the connection termination information to the registration agent for a device for which a response to the service availability inquiry is not returned for a predetermined time or there is a connection termination (Bye) message, and the registration agent terminates the connection. Transferring information to the context registry to change state information of the device: Service dynamic state reflection method of the sub-network in the ubiquitous, characterized in that it comprises a.

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