# CATSWoTS: Context Aware Trustworthy Social Web of Things System
## 1 Introduction  
The unfolding of the Internet of Things (IoT) revolution has taken place so rapidly before our eyes that it has started dominating the different spheres of life. From smart health to smart home, from smart city to smart community, and smart applications for businesses, the services of IoT are playing a significant role. The all-encompassing term of IoT is a network that connects the physical world with the cyber world through smarts objects, sensors, actuators, Radio Frequency Identification (RFID) tags and even through virtual objects and things [1]. The future of IoT seems to be very promising. IoT connects billions of heterogeneous physical and virtual objects. The issue of interoperability is attempted to resolve by exploiting the concept of web technologies hence devising the term of Web of Things (WoT). WoT extends the concept of IoT. WoT connects devices to the Internet, incorporate web servers, models the services and then introduces these services as RESTful [2]. Web services are being used to fully integrate distributed and heterogeneous devices. The web services are the foundational elements of Service Oriented Architecture (SOA). In SOA systems, devices can play the role of a service provider and service consumer as well if needed. The compatible service APIs make usages of SOA technologies like REST, WS-* and CoRE [3]. An Arrowhead framework [4] based on SOA for enabling the interoperability among billions of heterogeneous devices is also proposed. In short, WoT lets thereal-world and virtual objects be part of the World Wide Web (WWW). This is the reason that the concept of WoT is incorporated in the proposed research to resolve the interoperability issue amicably. Social IoT encompasses social networks and peer-to-peer (P2P) networks in which autonomous social relations can be established [1]. The IoT gets social when things become smarter. In this kind of network, things may provide services and things may seek services from others. Besides this, recommendations can be taken for trustworthy things including the physical and cyber world. The things are owned by humans and worked for humans; therefore, it is important to consider the social relations among the owners of the things [1]. Keeping in view that the importance of social relations for humans and the trust level they put on these relations is more than they put on strangers; this important aspect is considered in this research. In the presence of billions of service providers, finding trustworthy services is not an easy task. Evaluating the trustworthiness of a service provider is a critical task. Identifying which parameters are significant, for shortlisting the qualified trustworthy service providers, is a matter of grave concern. In this paper, the problem of finding a trustworthy service provider has been tackled through proposing a trust recommender and then managing the trust for the evaluation of services. The motivation behind this research is to focus on finding and separating those trustworthy services which not only fulfill the Quality of Service (QoS) criteria like reliability, availability but also the context-awareness. Context is a piece of information that manifests the situation or position of an entity [5], whereas context awareness depicts such a system which provides relevant information based on its context [5]. Though many systems had been proposed for the past two decades; however, with the introduction of IoT, where billions of things connect, context awareness has become a challenge [5]. Collecting and processing data from these things is not an easy task. The data will be valuable only if it has been processed and analyzed. Context-aware computing is significant for evaluating the trustworthiness; therefore, in the CATSWoTS, this aspect is also being considered so that a service seeker may get a list of qualified services based on QoS.