May 31 International Journal of advanced studies in Computer Science and Engineering IJASCSE, Volume 3, Issue 5, 2014 CONTEXT MANAGEMENT STRATEGIES IN WIRELESS NETWORK Giadom, Vigale Leelanubari Dr. E. E. Williams M.Sc Student, Department of Computer Science Department of Computer Science University of Port Harcourt University of Calabar Rivers State, Nigeria Cross River, Nigeria Abstract—Context management strategies in wireless technology are information. These information forms a key component of any dependent upon the collection of accurate information from the pervasive computing. HE FURTHER CATEGORIZES CONTEXT individual nodes. This information (called context information) can MANAGEMENT INTO: be exploited by administrators or automated systems in order to decide on specific management concerns. While traditional A. MOBILE ENVIRONMENT approaches for fixed networks are more or less centralized, more complex management strategies have been proposed for wireless B. HOME/OFFICE ENVIRONMENT networks, such as hierarchical, fully distributed and hybrid ones. The reason for the introduction of new strategies is based on the dynamic C. ADHOC ENVIRONMENT and unpredictable nature of wireless networks and their (usually) Ilka (2001) stated that Context management at the access limited resources, which do not support centralized management solutions. In this work, efforts is being made to uncovered some Reuters is considered to support establishment, updating and specific strategies that can be used to managed context information deleting of the mobile nodes context information for a that reaches the centre of decision making, the work is concluded particular service, aimed for instance at multicast listening, with a detail comparison of the strategies to enable context Quality of Service (QoS), reservation, accounting and application developers make right choice of strategy to be employed security. in a specific situation. In all these works, Context Management Strategies in Wireless Keywords— Context Management, Centralized Strategy, Technology was not really captured. The dearth of materials, Hierarchical Strategy, Distributed Strategy, Hybrid Strategy (key research works and active research groups on Context words) Management Strategies in Wireless Technology have I. INTRODUCTION necessitated this project. This project captures a practicable area of computing called networking, specifically wireless Researches in context-aware computing have given rise to technology. A research on Context Management Strategies in several application models, theories, principles, prototype, wireless technology is necessary as the world is gradually frameworks and middleware systems for describing context moving away from wired network to a more reliable, cable but the development of context-aware programs and less network. This cable less network is convenient, flexible, applications is still a difficult task [13]. This stems from the fast, dynamic, secured and has a wider coverage. fact that there is a limited or no knowledge on the set of strategies to be employed for optimal performance and to II. CONTEXT ANALYSIS enhance the efficiency of a context application. Also current middleware applications require a global knowledge of the context-aware infrastructures in order to establish context A. CONTEXT IN NETWORK ENVIRONMENT based interactions [13]. This project seeks to explore Context Schilit et al, 1994, the pioneers of context-aware computing, Management Strategies in wireless Technology. regard context to be location, identities of nearby people and object, and changes to those objects. They consider where you A handful of research has been done on context management, are, whom you are with, and what resources are nearby to be although most of these works center on context management the important aspects of context. Abowd et al.’s more recent in mobile and distributed network but little or no work has classification of context (Abowd et al, 1997) expands the being done on the strategies to be employed in managing the Schilit et al, 1997 definition. They define context as: “…any context information that comes into a context manager. information that can be used to characterize the situation of an Christine (2004) revealed that a context management system is entity. An entity is a person, place or object that is considered a distributed system that enables applications to obtain context relevant to the interaction between a user and an application, www.ijascse.org Page 7 May 31 International Journal of advanced studies in Computer Science and Engineering IJASCSE, Volume 3, Issue 5, 2014 including the user and application themselves.” This means context-aware applications. The main task of a context that any information that depicts the situation of a user can be management system is to match consumer’s interests with entitled context. The temperature, the presence of another probed context information. The complexity of context person, the nearby devices, the devices a user has at hand and management in a distributed scenario is defined by the the orientation of the user are examples. wideness of an interest, i.e. the number of context management systems that should be involved in an interest matching. If a distributed scenario is also open, heterogeneous B. CONTEXT MANAGENENT and dynamic then the wideness of an interest is variable, as a Context management encompasses all the processes involved result of characteristics such as dynamic introduction of new in the collection, exchange and processing of context sensors and evolution of context models. The support of information. This is necessary because: context interest of variable wideness imposes challenging The context information can be distributed in both requirements for context management systems [16]. network and mobile terminal. Therefore, it is difficult to E. CONTEXT AWARE PROGRAMS collect and need to be exchanged. Wireless link is a bottle neck for context exchange. Hence These are set of instructions, commands and applications that the information exchange between the mobile node and can adapt and perform tasks on ambient conditions in the networks should be minimized. physical or the virtual world. In context-aware applications, The context information can be either dynamic or static. adaptations are triggered by changes of certain context The dynamic information needs to be updated frequently. information. For example, smart applications designed to Moreover, the amount of context information can be support meetings may automatically transfer a presentation to enormous. For a specific service, some context information is a projector as soon as the presenter enters the meeting room. relevant, some is not relevant. Therefore, we need a data In this case, both the location of the presenter and his/her role structure to compile the context information effectively. in the meeting room are basic pieces of context information used to trigger the transfer of the presentation. Basically, the C. CONTEXT INFORMATION development of a context-aware application, as in this Context information is data that describes the state of a certain example, involves the description of the actions to be triggered entity at a specific moment. Context information makes according to a set of contextual conditions. A same piece of applications and networks aware of their situation and context information may be used for different purposes. The improves certain functions in a network or applications, but is location of the presenter, for example, may also be used by typically not critical in the sense that functionality cannot be another application to disseminate his availability status for an provided at all if the context information is not available. instant communicator. Moreover, this context information However, context information is expected to play a vital role may be provided by different sensors, such as a proximity in supporting autonomic decision making and is regarded as a sensor to identify if the user is inside the classroom and using necessity for self-organization [3]. a microphone connected to voice recognition software to Basically, there are two classifications of context information identify specific users in the classroom [16]. which are Static Context Information and Dynamic Context Information. III. CONTEXT IN A WIRELESS NETWORK D. CONTEXT MANAGEMENT SYSTEMS Various contexts can be observable in a wireless network A context management system is either a centralized system configuration; information that depicts the situation of a that enables applications to obtain context information about user can be entitled context. These context among others (mobile) users and forms a key component of any pervasive include: WI-FI signal availability, signal intensity, network traffic, geography of WI-FI users, surrounding buildings, computing environment (Christine, 2004). Context structures and vegetations, wireless access points, management systems are however very environment-specific coverage areas, devices used such as PDAs, mobile (e.g., specific for home environments) and therefore do not phones, laptops, desktops, tablets etc, others include the interoperate very well. This limits the operation of context- amount of data transferred, capacity, performance etc. aware applications because they cannot get context These and many more are set of measurable characteristics information on users that reside in an environment served by a used in defining the state of a given entity. These