Earticle

Good image quality and high hiding capacity are two basic requirements of information hiding systems. Technically, it is very challenging to achieve these two factors simultaneously. The purpose of obtaining either high hiding capacity or good image quality are various from application to application. Inspired from the wet paper codes proposed by Fridrich et al., we propose an information hiding scheme for grayscale images. The proposed scheme first uses a secret key to randomly select a subset of pixels from a cover image as dry pixels. Next, the toral automorphism is applied to the cover image to maximize the number of dry pixel pairs. Then, each secret digit in the base-9 numeral system is embedded into one dry pixel pair. The experimental results show that the proposed scheme can achieve good image quality (i.e., PSNR > 46 dB) and flexible hiding capacity. In addition, unauthorized users without knowing the secret key and the secret parameters used for the toral automorphism can not extract the embedded message.

The recent convergence of ubiquitous computing and context-aware computing has seen a considerable rise in interest in applications that exploit aspects of the contextual environment to enhance implicit user interaction, offer services, present information, tailor application behavior or trigger adaptation. However they are often insufficient to provide adequate environments for people with special needs and allow them to be an integral part of society. This paper presents our approach to enhance environment services to peoples with special needs. Particularly it highlights the data representation and implementation of this approach under a framework based on the Web Ontology Language OWL-DL. A prototype of this framework was integrated in a smart home demonstrator and tested with users under a laboratory conditions.

Kitchen as a space for social interaction and communication has been neglected in current HCI design. Most researches on kitchen mainly focus on cooking activities, so to correct human’s frailties become main development in HCI research. Here instead of creating some artifact to improve working activities in the kitchen, we direct our study to design a system that aims to increase social interactions and communications among people. A tangible interactive recipe system embedded in kitchen island was introduced and evaluated. The results indicate that visual representation of dishes could facilitate people’s share of experiences and positive responses toward each other. A record of people’s favorite foods could also make food preparation easier and understand others’ preferences. Moreover, people enjoyed the intuitive way of the system’s interaction. Nevertheless, although people made some flavor changes in their final decision, people commented on lacking of personal creativity in current system. Further implications on sociable design are discussed in this study.

In this paper we propose the design and development of a flexible smart home architecture using a peer-to-peer (P2P) approach. We specifically focus on two distinct aspects of this proposed architecture. First, we analyze how the different home devices and services can be represented as individual peers in order to have a decentralized system, which is scalable by nature and avoids the single point-of-failure usually attributed to a centralized server. Second, we investigate the distribution of application workflow logic among the peers to develop a flexible home architecture with autonomous behavior of the peers. We analyze the suitability of Devices Profile for Web Services (DPWS) to realize the proposed P2P-like architecture for the smart home. We further show how to distribute the application workflow logic among the peers and yet achieving the same global behavior of the system. Our experimental results show that DPWS provides tools and techniques, in particular its discovery and eventing mechanism, which can be leveraged to provide flexibility and autonomy in the overall architecture.

Providing context-dependent security services is an important challenge in ambient intelligence. The complexity and the unbounded nature of such systems make it difficult for software developers to integrate security solutions. In order to solve this problem, in this paper we discuss and address multifold security challenges involved in the implementation of remote healthcare in smart homes using the security patterns approach. First the security challenges are derived from a real-world, industrially relevant scenario. Then it is shown how validated security techniques and mechanisms providing certain security properties can be captured and implemented in security patterns. Next security patterns are applied to satisfy security requirements in the smart home healthcare scenario. The process is exemplified thanks to a running prototype implementing the scenario.

The recent ubiquitous/pervasive technologies allow general household appliances to be connected within the network at home. The home network system (HNS, for short) is comprised of such networked appliances to provide various services and applications for home users. The great advantage of HNS lies in integrating (or orchestrating) features of multiple appliances, which yields more value-added and powerful services. We call such services HNS integrated services. In developing and providing a HNS integrated service, the service provider must guarantee that the service is safe for inhabitants, house properties and their surrounding environment. As for the HNS integrated services, however, we have to consider the safety much more carefully. This paper presents a systematic method that can derive the verifiable safety properties from a given HNS model and hazard contexts. Specifically, we propose the HNS Hazard Analysis Model (HNS-HAM) for deriving safety properties with conducting a goal-oriented analysis. The analysis yields cause-and-effect chains from the abstract hazard contexts to the concrete attributes and operations of HNS objects (appliances, services, and environment). Then the safety properties and their responsible operations are derived from the complete model, which give the strong rationale of the safety of the HNS. On the other hand, to make the proposed method more practical, it is necessary to save the analysis cost while appliances and services in the HNS are added or changed. For this, we have also proposed the notion of the hazard template, which characterizes the generic portion of the HNS-HAM. For every hazard context, the hazard template is supposed to be constructed once by the safety experts. The template can be reused for various kinds of the HNS objects for the common hazard context. The reusable templates make it possible to save the analysis cost and improve the quality of the HNS-HAM.

In this work, we introduce the Privacy Manager, a user interface designed to allow non-expert users to manage privacy in the envisioned era of pervasive computing. The Privacy Manager is part of the implementation of the User-centric Privacy Framework, which was introduced as a novel mechanism to enable personal privacy for the inhabitants of the smart home. The Privacy Manager interface incorporates a set of application parts designed especially to meet the requirements of user friendliness, and privacy awareness, with the goal of making privacy management an affordable task for common users. Our first prototype allows to: i) customize permissions for the disclosure of their personal data, ii) control active and passive interactions with services, iii) define obligations to be negotiated on the usage of the data, upon transmission, iv) be aware of privacy related issues such as granted and denied permissions, v) apply alternative privacy mechanisms to access control, as white lying and obfuscation, vi) adhere to enterprise privacy policies based on a contractual relationship with an enterprise or organization. Providing people with tools to control their privacy is critical to guarantee the success of pervasive computing.