فناوري عامل سيار براي بهبود دستيابي به منابع مكاني موجود در مراكز هماهنگي داده

Mobile Agent Technology to Improve the Access to Spatial Resources at Clearing Houses

امروزه با توجه به گسترش استفاده از نقشه‏ ها و سیستم ‏های اطلاعات مكانی در سازمان ‏های مختلف، روش جمع‌آوری لایه‌های مختلف داده برای تهیه اطلاعات مكانی مورد نیاز، از اهمیت بالایی برخوردار است. از طرفی موازی كاری در تهیه اطلاعات مكانی و ذخیره‌سازی آن در منابع پراكنده در بیشتر موارد موجب صرف هزینه‌های سنگینی می‌شود. این امر موجب طرح زیرساخت مكانی و به دنبال آن مراكز هماهنگی داده برای ارتباط بین ارائه‌دهنده و درخواست‌كننده شده است، گرچه برای محاسبات توزیع‌شده و ایجاد مراكز هماهنگی داده تاكنون روش‌های مختلفی ارائه‌شده، ولی با این وجود روش‌های موجود با مشكلاتی در شبكه ارتباطی هنگام افزایش حجم درخواست‌ها و اطلاعات روبرو می‌شوند. در این پژوهش از عامل سیار كه توانایی حركت و تصمیم گیری در شبكه را بصورت خودمختار داشته جهت ایجاد مراكز هماهنگی داده برای رسیدن به نقشه و اطلاعات مكانی مورد نیاز موجود در پایگاه‌های داده سازمان‌های مرتبط و جلوگیری از صرف هزینه‌های زیاد تهیه نقشه و موازی كاری استفاده شده است. بر این اساس مراكز هماهنگی داده از خصوصیات عامل‌های سیار از قبیل كاهش بار شبكه، مقاومت و پایداری و توانایی كار در روی محیط‌های ناهمگون برخوردار می‌شوند. نمونه عملی پیاده شده برای یك مركز هماهنگی SDI، موید توانایی‌های یادشده بوده است.

Nowadays, due to widespread use of maps and geospatial information systems in different organizations, different data layers collection methods for the preparation of required spatial data information, is of great importance. On the other hand doing in parallel in the preparation of spatial data and its storage in disparate sources often cause heavy costs. This has caused spatial infrastructure projects and clearing houses for communication between providers and the applicant. In this case the spatial data infrastructure is a communication network between the databases, systems and services, applications, technologies and policies that in different standard levels allows user access to data.  As well as the clearing house in spatial information technology means decentralized system of information that each of information provides a description of spatial data. Although different methods of distributed programming on the network, such as a code on demand, client server and Web services are provided , for distributed computing and creating clearing house, but available methods when increasing the volume of requests and information faced with problems. Increasing network traffic, creating bottlenecks and delays in network, problem in computing on client-side and the need for special plug-ins, reducing network security and access to intelligence information, the possibility of disseminating information and lack of commercial use, reducing network power and other problems are of weaknesses of the common methods of distributed computing. By investigating the mobile agent it can be present to achieve the required objectives of the clearing houses and reducing problems of existing methods. Mobile agent provide a strong alternative and pattern for network and distributed computing which has a clear difference with the current common methodologies and indicators such as, code-on-demand, client-server and Web service method, which led to the replacement of use of mobile agent with current distributed computing methods as well as the use of this system, along with methods to reduce the existing problems. In artificial intelligence the agent is anything that can understand their environment through sensors and relationships and environment is also react by defined incentives. In this research mobile agent with autonomous ability to move and make decision on network is used to create a clearing houses to achieve the maps and spatial information needed in related organization databases and avoid spending high costs to mapping and doing in parallel. In implementing this project a clearing house has been created based on the use of mobile agents in order to meet legal and real users’ needs to access spatial data stored locally across multiple computer systems. For this purpose 4 database related to organizations responsible for mapping including available metadata and maps were considered. Accordingly using presented in this study clearing house have characteristics of mobile agents such as network load reduction, stability and resilience and ability to work in heterogeneous environments. Practical implementation example for a SDI clearing house confirms above mentioned capabilities.