u-BabSang: a context-aware food recommendation system

In this paper, we propose a context-aware food recommendation system for well-being care applications. The proposed system, called u-BabSang, provides individualized food recommendation lists at the dining table, and is based dietary advice in the typical Korean medical text. Our proposed system receives a user’s profile, physiological signals, and environmental information around the dining table in real time. To operate our system, we present a method for user specified analysis, and also describe time-division layered context integration which integrates the multiple contexts obtained from the sensors. Thus, our system recommends appropriate foods for each individual’s health at the table in real time.     

CASD: Management of a context-aware service directory

Traditional web service discovery is strongly related to the use of service directories. Especially in the case of mobile web services, where both service requestors and providers are mobile, the dynamics impose the need for directory-based discovery. Context plays an eminent role with mobility, as a filtering mechanism that enhances service discovery through the selection of the most appropriate service. However, current service directory specifications do not focus on mobility of services or context-awareness. In this paper, we propose CASD, a context-aware service directory, envisioned as a context-based index for services on top of any traditional service directory, and design algorithms for construction, search, update and merge of such directories. Furthermore, we describe the architecture of our system for context-aware service discovery, we present a prototype implementation and discuss the experimental results as well as the overall evaluation. The contribution of this work is the proposal for a novel, enhanced representation model for a context-aware service directory.     

ContextPhone: a prototyping platform for context-aware mobile applications

Smart phones are a particularly tempting platform for building context-aware applications because they're programmable and often use well-known operating systems. There's a gap, however, between the operating systems' functionality and the features that application developers need. To fill this gap, we've designed and developed ContextPhone, a software platform consisting of four interconnected modules provided as a set of open source C++ libraries and source code components. ContextPhone runs on off-the-shelf mobile phones using Symbian OS and the Nokia Series 60 Smartphone platform. ContextPhone was developed using an iterative, human-centered design strategy. It thus helps developers more easily create applications that integrate into both existing technologies and users' everyday lives.     

Telme: a personalized, context-aware communication support system

True global communication will require more than just language translation technologies. To fully understand each other, people also need context-specific information. The authors have developed Telme, a support system that gives users real-time information to help bridge the knowledge and experience gap. The authors explain the Telme framework for wearable computers connected to a central knowledge base server. The server controls a background knowledge database and downloads data on user request.     

Learning in a u-Museum: Developing a context-aware ubiquitous learning environment

Context-awareness techniques can support learners in learning without time or location constraints by using mobile devices and associated learning activities in a real learning environment. Enrichment of context-aware technologies has enabled students to learn in an environment that integrates learning resources from both the real world and the digital world. Although learning outside of the traditional classroom is an innovative teaching approach, the two main problems are the lack of proper learning strategies and the capacity to acquire knowledge on subjects effectively. To manage these problems, this study proposes a context-aware ubiquitous learning system (CAULS) based on radio-frequency identification (RFID), wireless network, embedded handheld device, and database technologies to detect and examine real-world learning behaviors of students. A case study of an aboriginal education course was conducted in classrooms and at the Atayal u-Museum in Taiwan. Participants included elementary school teachers and students. We also designed and used a questionnaire based on the Unified Theory of Acceptance and Use of Technology (UTAUT) theory to measure the willingness for adoption or usage of the proposed system. The experimental results demonstrated that this innovative approach can enhance their learning intention. Furthermore, the results of a posttest survey revealed that most students' testing scores improved significantly, further indicating the effectiveness of the CAULS.     

Outlier trajectory detection through a context-aware distance

Pattern Analysis and Applications - This paper presents an original method to detect anomalous human trajectories based on a new and promising context-aware distance. The input of the proposed...     

An application of a context-aware file system

Ubiquitous computing environments stretch the requirements of traditional infrastructures used to facilitate the development of applications. Activities are often supported by collections of applications, some of which are automatically launched with little or no human intervention. This task-driven environment challenges existing application construction and data management techniques. In this paper, we describe a file system that organises application data based on contextual information, imports user data based on its physical presence, and supports format conversions to accommodate device context. We describe several applications that we have developed within our ubiquitous computing infrastructure and show how they leverage the novel features of our file system to simplify their complexity.

Dynamic context-aware personalisation in a pervasive environment

In the development of ubiquitous and pervasive systems, it is understood that mechanisms are required to take adequate account of user preferences. This paper presents several key challenges for personalisation in pervasive environments and introduces the Daidalos solution developed as part of a European research project, Daidalos. The Daidalos personalisation system architecture goes beyond customary simplistic preference management to provide two aspects of dynamicity: first in the establishment of user preferences, where learning mechanisms are used to refine and update preferences when the need arises; second during the application of preferences whenever the context of the user changes. The paper discusses how this system meets the outlined challenges and details how the system has been evaluated.     

Towards a semantic infrastructure for context-aware e-learning

Architectural supports, e.g., user context processing and learning content management are essential for facilitating the development and proliferation of context-aware e-learning services. In this paper, we propose a context-aware e-learning infrastructure called Semantic Learning Space. It leverages the Semantic Web technologies to support semantic knowledge representation, systematic context management, interoperable content integration, expressive knowledge query, and adaptive content recommendation. The functionality encapsulated in the infrastructure handles the common, time-consuming and low-level details in learning context processing and content management. The architectural design and enabling technologies are described in detail. Finally, the prototype implementation and preliminary experimental results are presented.     

Adam: Identifying defects in context-aware adaptation

Context-aware applications, as a typical type of self-adaptive software systems, are receiving increasing attention. These applications continually adapt to environmental changes in an autonomic way. However, their adaptation may contain defects when the complexity of modeling all environmental changes is beyond a developer's ability. Such defects can cause failure to the adaptation and result in application crash or freezing. Relating these failures back to responsible defects is challenging. In this paper we propose a novel approach, called Adam, to assist identifying defects in the context-aware adaptation. Adam monitors runtime errors for an application, logs relevant error information, and relates them to responsible defects in this application. To make our Adam approach feasible, we investigate the error types that are commonly exhibited by various failures reported in context-aware applications. Adam detects these errors in order to identify responsible defects in context-aware applications. To detect these errors, Adam formally models the adaptation semantics for context-aware applications, and integrates into them a set of assertion checkers with respect to these error types. We experimentally evaluated Adam through three context-aware applications. The experiments reported promising results that Adam can effectively detect errors, identify their responsible defects in applications, and give useful hints on how these defects can be fixed.     

Can: A context-aware NAT traversal scheme

Network Address Translation (NAT) is a technique commonly used to share one public IPv4 address among several hosts located behind a NAT device. NAT devices typically block session requests originating from outside, causing NAT traversal problem that prevents the establishment of peer-to-peer (P2P) sessions. There have been many proposals for the NAT traversal problem. However, existing methods induce high connectivity check delay and resource demand when finding a communicating path, calling for a routine that determines the path best suited for a given pair of communicating peers. This study proposes CAN, a Context-Aware NAT traversal scheme which gathers and exchanges network-context information to find the most appropriate path for two communicating peers behind NAT devices. We have implemented CAN and conducted extensive experiments with off-the-shelf NAT devices to compare the performance of CAN with Interactivity Connectivity Establishment (ICE), the most acknowledged approach to creating a session across NATs. Experimental results show that CAN outperforms ICE in terms of direct communication ratio, connectivity check delay and message overload when checking connectivity.     

COMUNICAR: designing a multimedia, context-aware human-machine interface for cars

The European Union co-funded COMUNICAR (communication multimedia unit inside car) project designed and developed an integrated multimedia human–machine interface (HMI) able to manage a wide variety of driver information systems (from entertainment to safety). COMUNICAR proposed an innovative information provision paradigm, in which the on-vehicle HMI is able to tailor the delivery of the information in real time according to the actual driving context and the drivers workload. COMUNICAR adopted a user-centred design process involving an iterative development based on extensive user tests since the early phases of the project. This approach was particularly useful to define and improve the layout of the user interface and specify the rules that decide the scheduling and the modalities of the delivery of the information messages to the driver. This paper introduces the COMUNICAR concept and the user-centred flow of design. Then, a concrete case of user-test driven, iterative improvement of a systems functionality is presented. We also briefly describe two software tools that we have designed to enhance the development process in a user-centred perspective. Finally, the future evolution of the concept of smart and safe information scheduling is sketched and discussed.

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Toward context-aware computing: experiences and lessons

To minimize distractions, a pervasive-computing environment must be context-aware. The authors define an activity-attention framework for context-aware computing, discuss the spatial and temporal aspects of applications they developed, and introduce a pervasive-computing architecture.     

Towards a programming framework for activity-oriented context-aware applications

Context-aware system is an emerging research area in recent years. Context plays an important role in these systems. In most existing work, context is treated as all relative elements in the environment of an application, and the scope of context is predefined by the developers during the development. However, it is difficult to analyze, specify, and organize everything in the environment accurately and completely; and even when it is possible, the developed applications are difficult to extend or modify as the requests for environment may change over time. In this paper, we focus on activity-oriented context-aware (AOCA) applications where the requests for environment are highly dependent on user activities, and propose a programming framework for developing AOCA applications. In particular, we first present a concept model for describing the notions of activity-oriented context. Next, based on the concept model, we describe the details of the programming framework as well as a development tool. Moreover, we provide a platform to support the runtime of AOCA applications, and demonstrate the advantages of our programming framework through experimental evaluations.     

Adaptive video object proposals by a context-aware model

Most previous works focus on image object proposals while few on video object proposals. Besides, the existing explorations about video object proposals mainly concentrate on localizing the dominant object. In this paper, we aim at exploring a uniform framework for proposing multi-objects in videos no matter they are in the foreground or background. The method is derived from image object proposals, and makes best use of video characteristics. To achieve this task, we propose an adaptive context-aware model for video object proposals. First, spatial candidate windows are generated by the image method for acquiring the adequate bounding box samples. Temporal boxes are calculated by the motion based mapping. Considering the mapping loss, we define a box confidence coefficient contributing to keeping the proposal consistency and restraining the motion blur. The output proposal bounding boxes are ranked based on the scores calculated by the weighted scoring system. The proposed method is separately evaluated on the proposed multi-object dataset and the public dataset. The results compared with several state-of-the-arts show that our method has the most satisfactory overall performance for multi-object proposals in videos.     

FCT: a fully-distributed context-aware trust model for location based service recommendation

With the popularity of location based service (LBS), a vast number of trust models for LBS recommendation (LBSR) have been proposed. These trust models are centralized in essence, and the trusted third party may collude with malicious service providers or cause the single-point failure problem. This work improves the classic certified reputation (CR) model and proposes a novel fully-distributed context-aware trust (FCT) model for LBSR. Recommendation operations are conducted by service providers directly and the trusted third party is no longer required in our FCT model. Besides, our FCT model also supports the movements of service providers due to its self-certified characteristic. Moreover, for easing the collusion attack and value imbalance attack, we comprehensively consider four kinds of factor weights, namely number, time decay, preference and context weights. Finally, a fully-distributed service recommendation scenario is deployed, and comprehensive experiments and analysis are conducted. The results indicate that our FCT model significantly outperforms the CR model in terms of the robustness against the collusion attack and value imbalance attack, as well as the service recommendation performance in improving the successful trading rates of honest service providers and reducing the risks of trading with malicious service providers.