Sejin Chun

Semantic description, discovery and integration for the Internet of Things

To share and publish the domain knowledge of IoT objects, the development of a semantic IoT model based directory system that manages meta-data and relationships of IoT objects is required. Many researches focus on static relationships between IoT objects. However, because complex relationships between various resources change with time in an IoT environment, an efficient method for updating the meta-data is required. Thus, we propose an IoT-DS as the IoT directory that supports semantic description, discovery, and integration of IoT objects. Firstly, we introduce a semantic IoT component model to establish a shared conceptualization. Secondly, we present general cases of relationships to efficiently interact between IoT-DS and IoT objects. Thirdly, we construct IoT-DS as a Web portal. Finally, we verify in our evaluation study that the query processing time and communication workload imposed by the proposed approach are reduced.

IoT Service Selection Based on Physical Service Model and Absolute Dominance Relationship

The Internet of Things (IoT) is a paradigm where real-world entities can be connected to the Internet and provide services with the help of attached devices. With the development of IoT technologies, the number of devices deployed around the world as well as their services are increasing rapidly. Thus, selecting an appropriate service which satisfies a users requirements from such many services becomes a time consuming challenge. Therefore, to address this issue we propose a Physical Service Model (PSM) to describe heterogeneous IoT physical services. PSM contains three core concepts (Device, Resource and Service) and specifies their relationships. Based on PSM, we define four quality of service (QoS) attributes and rate candidate services according to user requirements. In order to dynamically aggregate individual QoS ratings and select physical services, we propose a Physical Service Selection (PSS) method which takes a user preference and an absolute dominance relationship among physical services into account. Finally, experiments are conducted to evaluate the performance of the proposed method.

Short paper: Semantic URI-based event-driven physical mashup

To enhance the integration of different IoT application domains, we propose a two-layered IoT information model that consists of domain-independent and domain-specific models. In addition, for the meaningful composition of things and their services, a semantic URI as a unique identifier is allocated to a thing. Finally, a modeling approach of constructing physical mashups is proposed for the event-driven composition of IoT services. In order to show the efficiency of the proposed event-driven physical mashup approach, an energy management scenario in u-campus is demonstrated as a case study.

A fast and scalable approach for IoT service selection based on a physical service model

Information Systems (ISs) have become one of the crucial tools for various organizations in managing and coordinating business processes. Now we are entering the era of the Internet of Things (IoT). IoT is a paradigm in which real-world physical things can be connected to the Internet and provide services through the computing devices attached. The IoT infrastructure is starting to be integrated with ISs thereby diminishing the boundaries between the physical world and the business IT systems. With the development of IoT technologies, the number of connected things and their available physical services are increasing rapidly. Thus, selecting an appropriate service that satisfies a user’s requirements from such services becomes a time-consuming challenge. To address this issue, we propose a Physical Service Model (PSM) as a common conceptual model to describe heterogeneous IoT physical services. PSM contains three core concepts (device, resource, and service) and specifies their relationships. Based on the proposed PSM, we define three types of Quality of Service (QoS) attributes and rate candidate services according to user requirements. To dynamically rate QoS values and select an appropriate physical service, we propose a Physical Service Selection (PSS) method that takes a user preference and an absolute dominance relationship among physical services into account. Finally, experiments are conducted to evaluate the performance of the proposed method.

Towards a Semantic Model for Automated Deployment of IoT Services across Platforms

In the landscape of Web of Things (WoT), we encounter various WoT platforms. The WoT platforms can collect, manage and mash up a huge mass of things and their data by using Web technologies. Considering heterogeneous things deployed across different platforms, the interoperability issue between things and platforms has been raised as one of major challenges in achieving the vision of the Internet of Things (IoT). In this paper, we propose a Semantic Service Description (SSD) ontology to guarantee the semantic consistency of a service description. We also present an approach to generating a service description and deploying a set of heterogeneous things to different platforms automatically. Through the implementation of a prototype, the applicability of our proposal is demonstrated and the experimental results are discussed.

Hypergraph-based overlay network model for the Internet of Things

As the Internet of Things (IoT) is gaining tremendous popularity from industries to researchers for its potential to provide business opportunities and academic contributions, several research challenges have risen to the surface. With billions of IoT objects being produced, connected and interacting, one of the challenges claim that there is an imperative need for ways to organize and manage the objects effectively. This paper, therefore, proposes a network-based multidimensional structure to model the IoT for efficient management and discovery of IoT objects. In addition, we address various research issues that must be considered in designing the proposed model. To test the feasibility of the model, we present numerous experiments performed on our smart home automation demo box, along with their justifications.

Automated mashup of CoAP services on the Internet of Things

The Constrained Application Protocol (CoAP) is a specialized Web transfer protocol for use with constrained devices and networks in the Internet of Things (IoT). Although a single CoAP service provided by a CoAP-enabled device has its own value for its users, the functionality provided by an individual CoAP service is limited. Hence, an efficient method of manipulating a set of CoAP services concurrently and processing their output data is needed. However, existing approaches require users to manually discover services and create mashups. Manual discovery and mashups are quite time-consuming tasks especially in an IoT paradigm. In this paper, we propose a novel CoAP Service Gateway (CoAP-SG) as an intermediate network node between a resource-constrained network and the Internet. The CoAP-SG enables users to create a CoAP service mashup automatically through a single HTTP request. In addition, semantic similarity is proposed to select similar services in case there is no exact matchings. Experimental results with a prototype implementation show that the proposed approach is feasible in terms of execution time and scalability.

Enhancing CoAP proxy for semantic composition and multicast communication

Due to the resource constrained nature of things on the Internet of Things (IoT), a mechanism of managing things and processing their data needs to be low-cost in terms of power consumption and network traffic. The Constrained Application Protocol (CoAP) is suitable for the IoT and supports multicast communication with things. However, multicast may lead to a traffic overload when the corresponding multiple responses travel through a CoAP-proxy concurrently. In this paper, we propose a novel approach to constructing a CoAP-proxy, which supports the efficient multicasting and grouping things based on the semantic description of a request. In addition, the proposed proxy merges multiple responses into an aggregated one, which is returned to a client. To demonstrate the feasibility, we implemented a prototype of the proposed CoAP-proxy and evaluated the performance of our approach in terms of the response time and network traffic.

Context-Aware Mashup for Smart Mobile Devices

A mobile mash up should be able to compose the component services in accordance with a users context. We propose a context-aware mash up method for smart mobile devices. For this purpose, a novel user request model is presented and the conventional service description model is extended. We propose a context ontology which can efficiently manage contextual information in a mobile environment. Furthermore, the proposed method undergoes three computations -- functional, I/O connectable and contextual matching. In particular, the contextual matching technique utilizes two types of contextual information that are proposed in this paper, implicit and explicit contexts. In order to evaluate the accuracy of the proposed method, a test registry based on real world Web APIs was built. Experimental results show an overall improvement of 26.7% in precision compared with the case where contextual information was not utilized.

Enabling smart objects discovery via constructing hypergraphs of heterogeneous IoT interactions

Recent advances in the Internet of Things (IoT) have led to the rise of a new paradigm: Social Internet of Things (SIoT). However, the new paradigm, as inspired by the idea that smart objects will soon have a certain degree of social consciousness, is still in its infant state for several reasons. Most of the related works are far from embracing the social aspects of smart objects and the dynamicity of inter-object social relations. Furthermore, there is yet to be a coherent structure for organising and managing IoT objects that elicit social-like features. To fully understand how and to what extent these objects mimic the behaviours of humans, we first model SIoT by scrutinising the distinct characteristics and structural facets of human-centric social networks. To elaborate, we describe the process of profiling the IoT objects that become social and classify various inter-object social relationships. Afterwards, a novel discovery mechanism, which utilises our hypergraph-based overlay network model, is proposed. To test the feasibility of the proposed approach, we have performed several experiments on our smart home automation demo box built with various sensors and actuators.