Abstract In the last few years the volume and size of web has been growing exponentially making it difficult to search the related pieces of information. To ease such problem, we have various general as well as focused crawlers. These two types of crawlers have their own features and limitations. In this paper we provide an extensive survey of the available... In the last few years the volume and size of web has been growing exponentially making it difficult to search the related pieces of information. To ease such problem, we have various general as well as focused crawlers. These two types of crawlers have their own features and limitations. In this paper we provide an extensive survey of the available general and focused crawlers. Besides we support our work with experimental results. Additionally we provide classification of the crawlers based on the parameter, the text analysis. Based on this survey we also project the near future developments in crawler research. Read More Read Less

Abstract Through this paper we investigate the significance of the online database system which can manage health records. The ehealth systems can able to store mass of individual patients' data. In this paper with the help of the investigation we have prepared a questionnaire to extract user perception and surveyed them extensively. We understand that many parameters and facts need to... Through this paper we investigate the significance of the online database system which can manage health records. The ehealth systems can able to store mass of individual patients' data. In this paper with the help of the investigation we have prepared a questionnaire to extract user perception and surveyed them extensively. We understand that many parameters and facts need to considered while processing health care data. It is also important to get specific as well as detailed data to plan the ehealth data system. Read More Read Less

Abstract Since the emergence of semantic web, researchers are facing a great challenge to represent the semantics of data in order to bring the actual web into its full power and hence achieve its objective. Herein, ontologies have emerged as the best means to accomplish the task because of their ability to explicitly specify the modeled domains. Indeed, ontologies are also... Since the emergence of semantic web, researchers are facing a great challenge to represent the semantics of data in order to bring the actual web into its full power and hence achieve its objective. Herein, ontologies have emerged as the best means to accomplish the task because of their ability to explicitly specify the modeled domains. Indeed, ontologies are also designed and developed to be shared between several organizations and information systems. Using ontologies as common or shared vocabularies requires a certain degree of interoperability between them. Therefore, the interoperability between different ontologies that model the same or similar domains is a challenging issue that can be handled by ontology mapping, alignment and merging processes. These later produce a Meta layer accessible by different applications and information systems, of course with preserving the semantics embedded in all the source ontologies. In this paper we aim to introduce the three main techniques of ontology interoperability, namely, ontology mapping, alignment and merging. These techniques constitute the basis for several other ontology interoperability techniques. This basis is built during the mapping discovery stage which is the meeting point for all ontology interoperability techniques. Several tools and algorithms for ontology Mapping, Alignment and Merging exist in the literature. In this paper, we will survey and compare the most outstanding ones after describing their common stage which is the mapping discovery process, then discuss the main forms of heterogeneities met and that have to be solved in order to bridge the semantic gap between the source ontologies. Read More Read Less

Abstract Microwave imaging technologies are widely investigated in the biomedical field where they rely on the imaging of dielectric properties of tissues. The key challenge in security applications using the microwave imaging is the image reconstruction methods adopted in order to gain clear image of illuminated objects inside human bodies or underneath clothing, Therefore in this paper we present subspace based... Microwave imaging technologies are widely investigated in the biomedical field where they rely on the imaging of dielectric properties of tissues. The key challenge in security applications using the microwave imaging is the image reconstruction methods adopted in order to gain clear image of illuminated objects inside human bodies or underneath clothing, Therefore in this paper we present subspace based TR-MUSIC algorithms for point targets and extended targets. The algorithm is based on the collection of the dominant response matrix reflected by targets at the transducers in homogenous background and use the MUSIC function to image it. We used the FDTD method to model the transducers and the objects to process its response matrix data in Mat lab. Clear images of metal dielectric properties have been clearly detected. Read More Read Less

Abstract The development of context-aware applications has been the subject of many research works in pervasive computing. As humans are getting more and more equipped with increasingly powerful mobile computing devices giving them access to online services, the need for personalized and adaptive information services is rapidly growing. Thus, the field of context-aware services has been, during recent years, a field... The development of context-aware applications has been the subject of many research works in pervasive computing. As humans are getting more and more equipped with increasingly powerful mobile computing devices giving them access to online services, the need for personalized and adaptive information services is rapidly growing. Thus, the field of context-aware services has been, during recent years, a field of intense research and has given rise to several approaches. However, in most of the approaches there is a lack of generic methodology for formalizing the development activity for this type of services and, consequently, this activity is very cumbersome and time consuming. Recently, some research works have advocated Model-Driven Development (MDD) as an approach for context-aware services development. In this paper we aim to review these works and their main features. Read More Read Less