Different elements of mobile network 

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... increasing popularity, functionality and getting smaller mobile devices, mobile learning has become a new trend in education. [Chen, Chang & Wang (2008)] illustrates that logging in with mobile devices is twice as much as logging with desktop or laptops to educational centers. According to [Yu-Feng Lan & Yang-Siang Sie (2010), Evangelos, Elissavet & Anastasios (2008), Huang, Huang & Hsieh (2008), Huang, Jeng & Huang (2009), Huseyin,Nadire, Erinc (2009), Liaw, Huang & Chen (2007)], using mobile devices to support learning activities offers improvement in communication and collaborative interaction, more learning opportunities for geographically dispersed persons and groups, encouraged active learning, enhanced learning feedback, emphasized time on task, and acquired content quickly. There are many motivations for resource management of educational services in mobile networks such as Performance- minimizing resource creation, initialization, acquisition, release, disposal, and access activities to ensure subscriber satisfaction ,Scalability -handling of dozens of network elements that must be represented in software needs highly sophisticated resource management techniques, Reliability -any downtime of mobile service can have both serious financial and non-financial ramifications for the provider, Flexibility, Quality of Service, Distribution, Failure handling and so forth. This study uses resource management patterns presented in related references ([Buschmann, Henny, Schmidt (2007)] , [Kircher & Jain (2004)]) and pattern automation method illustrated in [Zadahmad Jafarlou, Moeini, & Yousefzadeh Fard, (2010)] to solve the resource management requirements of educational services and underlying architecture in mobile networks. A mobile network typically consists of three different types of network elements [Longoni, & Laensisalmi (2001)]: Base stations, Radio Network Controllers, and Operation and Maintenance Centers (OMC) (Figure 1) along with several other network elements. The responsibilities of each of these three network elements are described below [Kircher & Jain (2004)]: Base- stations is responsible for communicating from mobile phones to the Radio Network Controller or to the core network, Radio Network Controllers (RNC) mediate calls between base stations, other RNCs and the core network, and Operation and Maintenance Center (OMC) manages the network of RNCs and base stations. The OMC is implemented as a software system distributed over multiple processes on multiple nodes includes a subsystem responsible for managing the network topology, a subsystem responsible for hosting database information about the topology, and a subsystem handling the user interface of the OMC and interacting with the network elements. The architecture of the base station consists of the Call Processing unit used for connection management and quality monitoring using RNC and the Operation & Maintenance unit used for simulating all hardware elements and selected software elements as a tree of objects and is responsible for monitoring and configuring all hardware and software elements. A base station's O&M unit registers its interface with the OMC in order to be managed and to report errors. The RNC architecture is similar to that of a base station. The Operation and Maintenance Center (OMC) is a network management system that is responsible for administration and monitoring of mobile network elements such as base stations and RNCs and consists of user interface, topological tree, to store network element-specific information in a database and tree management, to allow the user interface for contacting the O&M units of the network elements, such as base stations and RNCs, to retrieve actual data. Each network element possesses many properties, reflecting the state of its hardware, such as CPU boards and radio antennas, as well as software elements, such as established connections and available memory. It is easy to see that storing all this information requires a large database. Educational services need to transfer mass and continues data between servers and mobile phones. This requires high Performance in resource management approaches of underlying architecture of mobile networks. In this part, the main components of mobile network elements and related resource management issues are discussed. The base station components typically include Operation and Maintenance, Call Processing, Connection Management, and Startup Management [Kircher & Jain (2004)] running on the CPU boards in multiple processes. Every service interface of a component is associated with a reference. Lookup pattern helps to link the applications that are not linked statically. Every application registers its service interfaces with a lookup service. Broken and lost connections from the base station to the OMC waste the valuable resources. The Evictor pattern is solve this problem by either actively or passively verifying that currently unused connections and recycling them. When service interface of an OMC or OMC associated to a base station was changed, the service interface to the original OMC can become invalid. Leasing pattern can associates a lease with the reference of the OMC service interface. Since the lease will not be renewed by the OMC, the base station marks the reference as invalid and does not use that reference to the OMC. If the threads produced by O&M component to measuring of different aspects of the base station that run in parallel is prolonged, causes thread creation overhead and high system load, potentially put in danger the Call Processing unit. Pooling pattern manages the threads used for running long-lived actions. The thread pool internally assigns one of its threads to execute the action or keeps it in the queue for later processing. In addition for OMC element: Lookup pattern along with Iterator, Batch Method, Virtual Proxy and Enumeration Method patterns are used to discover the O&M service interfaces of the network elements, resource retrieval and resource access, Caching pattern makes available the base station state that has already been retrieved, even when a connection to the base station is currently unavailable, Strategy pattern is used to resource handling policies, Eager Acquisition pattern loads performance-critical resources, such as the state information of the top-level network elements, from the topological tree as soon as possible, typically on start-up, Lazy Acquisition pattern suggests that only rarely used resources are acquired on demand, immediately before the actual access of the resource takes place, Partial Acquisition pattern is used to partially acquire the necessary resources, Factory Method is used to resource creation and disposal, Coordinator pattern synchronizes the task of updating all the relevant network elements and new software version downloaded to the network elements is only activated when all participating network elements are ready to do so, When multiple resources must be coordinated, the Resource Lifecycle Manager pattern is valuable. Table 1, shows the main components of the base station and the OMC and related resource management. In [Zadahmad Jafarlou (2010)] a pattern-based MDA process was presented. Quantitative and qualitative evaluation of the method illustrate the ease of reuse, accurate automation, large granular of transformation among modeling levels of the patterns. This method also applied to creating a heuristic and pattern based merge sort [Zadahmad Jafarlou & Yousefzadeh Fard (2010)]. We used the mentioned approach to design a PIM for Lookup pattern that is one of the key patterns of resource management patterns. Figure 2 shows the Lookup pattern along with associated methods and relationships to manage lookup related operations using the mentioned method, along with descriptions about important operations. OMC connects remotely to the base stations and RNCs to the operation and maintenance purposes and therefore, it is configured with the IP addresses of all base stations and RNCs but the concrete service interface of the O&M component of the network elements is ...