Papers by Aart Van Halteren
Prolonged sitting time is a potential health risk, not only for people with an inactive lifestyle... more Prolonged sitting time is a potential health risk, not only for people with an inactive lifestyle, but also for those who do meet the recommended amount of physical activity. In this paper, we evaluate SitCoach, a mobile application to nudge people from their seats. SitCoach monitors physical activity and sedentary behavior to provide timely feedback by means of suggesting sitting
International Symposium on Computers and Communications, 2002
Developers of distributed multimedia applications face a diversity of multimedia formats, streami... more Developers of distributed multimedia applications face a diversity of multimedia formats, streaming platforms and streaming protocols. Furthermore, support for end- to-end Quality-of-Service (QoS) is a crucial factor for the development of future distributed multimedia systems. This paper discusses the architecture, design and implementation of a QoS-aware middleware platform for content delivery. The platform supports the development of distributed multimedia applications
Proceedings of the 5th International ICST Conference on Pervasive Computing Technologies for Healthcare, 2011
Research has demonstrated that a lack of cooking competence can be a significant barrier to healt... more Research has demonstrated that a lack of cooking competence can be a significant barrier to healthier eating. We present two studies from which we develop a set of requirements for a pervasive sensor infrastructure that will enable our Ambient Kitchen environment to measure cooking competence in an unobtrusive manner. From the first study we derive key characteristics and potentially measurable aspects of cooking competence. This study also led to the specification and design of a pervasive sensor infrastructure comprising of a set of kitchen utensils equipped with custom-made wireless accelerometers. The second study reports our initial findings from the use of the sensor infrastructure and demonstrates its potential to measure key indicators of cooking competence. Our studies provide initial evidence that cooking competence can be measured automatically using our proposed pervasive kitchen infrastructure.
Proceedings of the SIGCHI Conference on Human Factors in Computing Systems - CHI '13, 2013
ABSTRACT Household food practices are complex. Many people are unable to effectively respond to c... more ABSTRACT Household food practices are complex. Many people are unable to effectively respond to challenges in their food environment to maintain diets considered to be in line with national and international standards for healthy eating. We argue that recognizing food practices as situated action affords opportunities to identify and design for practiced, local and achievable solutions to such food problems. Interviews and shop-a-longs were carried as part of a contextual inquiry with ten households. From this, we identify food practices, such as fitting food, stocking up, food value transitions, and having fun with others and how these practices are enacted in different ways with varied outcomes. We explore how HCI might respond to these practices through issues of social fooding, the presence of others, conceptions about food practices and food routines.
Journal of Computers, 2006
Emerging wireless technologies enable ubiquitous access to networked services. Integration of wir... more Emerging wireless technologies enable ubiquitous access to networked services. Integration of wireless technologies into sensor and actuator nodes provides the means for remote access and control. However, ad hoc deployment of nodes complicates the process of finding, selecting and using these in a meaningful way. The use of a service discovery framework enables nodes to present themselves and the resources they hold. In this paper, we review the applicability of a number of well-known service discovery protocols in the context of networked nodes. Multicast DNS and Service Discovery (mDNS-SD) stands out with its auto-configuration, distributed architecture, sharing of resources, and wide area access. For wireless battery operated and resource constrained nodes, we seek to integrate SD and power management techniques. This leads us to a standards based infrastructure for service oriented sensor networks where; 1) nodes collaborate in an ad hoc fashion by using SD techniques to discover (and announce) resources locally and over the public Internet, 2) nodes preserve power through aggressive utilization of low power (sleep) modes, while yet being reachable for clients according to defined schemas, and 3) clients may access and configure nodes, and (if possible) access sleeping nodes by implicit wake-up procedures. To demonstrate the proposed infrastructure a complete experimental setup has been devised featuring; Bluetooth enabled nodes, lightweight implementations of mDNS-SD and communication stacks, Internet access through cellular/wired gateways, together with a public DNS server. Our experiments verify that mDNS-SD can be effectively deployed on small wireless sensor and actuator nodes and provides the basis of a service oriented infrastructure for low power sensor networks.
Lecture Notes in Computer Science, 2000
The availability of object middleware, such as CORBA, is rapidly being accepted as a means for co... more The availability of object middleware, such as CORBA, is rapidly being accepted as a means for cost effective and fast development for a wide range of distributed applications. Distributed applications that are built using these technologies often comprise many objects and become more and more complex. The deployment of such large distributed applications requires a significant improvement of management methods and tools. In this paper, we present a management architecture for object middleware based systems. We use message reflection to extend the middleware layer with management capabilities, i.e. we monitor the application by observing the messages exchanged between the objects of the distributed application. We argue why management should be transparent to the application developer and show that message reflection supports this management transparency. We have compared different mechanisms to implement message reflection in CORBA, and argue why portable interceptors are the most suitable. Finally, we describe our prototype and the lessons we learned.
Studies in health technology and informatics, 2004
The forthcoming wide availability of high bandwidth public wireless networks will give rise to ne... more The forthcoming wide availability of high bandwidth public wireless networks will give rise to new mobile health care services. Towards this direction the MobiHealth project has developed and trialed a highly customisable vital signals' monitoring system based on a Body Area Network (BAN) and an m-health service platform utilizing next generation public wireless networks. The developed system allows the incorporation of diverse medical sensors via wireless connections, and the live transmission of the measured vital signals over public wireless networks to healthcare providers. Nine trials with different health care cases and patient groups in four different European countries have been conducted to test and verify the system, the service and the network infrastructure for its suitability and the restrictions it imposes to mobile health care applications.
Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2009
This paper reports on the design of a vision-based exercise monitoring system. The system aims to... more This paper reports on the design of a vision-based exercise monitoring system. The system aims to promote well-being by making exercise sessions enjoyable experiences, either through real-time interaction and instructions proposed to the user, or via experience sharing or group gaming with peers in a virtual community. The use of avatars is explored as means of representation of the user’s
We present a survey on Service Oriented Architecture (SOA) and its extension Service Oriented Com... more We present a survey on Service Oriented Architecture (SOA) and its extension Service Oriented Computing (SOC). Provisioning of mobile and context-aware services or applications may benefit from SOA and SOC because they address similar issues like service discovery and service utilization. Moreover, SOC includes service management, service composition and orchestration and service transaction management which are also relevant for context-aware
Journal of Telemedicine and Telecare, 2007
Telemedicine implementations often remain in the pilot phase and do not succeed in scaling-up to ... more Telemedicine implementations often remain in the pilot phase and do not succeed in scaling-up to robust products that are used in daily practice. We conducted a qualitative literature review of 45 conference papers describing telemedicine interventions in order to identify determinants that had influenced their implementation. The identified determinants, which would influence the future implementation of telemedicine interventions, can be classified into five major categories: (1) Technology, (2) Acceptance, (3) Financing, (4) Organization and (5) Policy and Legislation. Each category contains determinants that are relevant to different stakeholders in different domains. We propose a layered implementation model in which the primary focus on individual determinants changes throughout the development life cycle of the telemedicine implementation. For success, a visionary approach is required from the multidisciplinary stakeholders, which goes beyond tackling specific issues in a particular development phase. Thus the right philosophy is: 'start small, think big'.
Topics in Biomedical Engineering, 2006
Lecture Notes in Computer Science, 2000
The requirements for the QoS of distributed applications are traditionally expressed in terms of ... more The requirements for the QoS of distributed applications are traditionally expressed in terms of network oriented or systems oriented parameters. In general, the users of these services are not interested or capable of specifying the QoS of their services in such technical terms. In this paper, we propose modeling and engineering concepts for the mapping of end user QoS onto system and network QoS. We introduce QoS agents in structured object middleware that relate end-user QoS specifications to multimedia stream bindings. In fact, the middleware layer supports QoS classes, i.e., a set of QoS characteristics. The end user QoS requirements, generally a set of nonorthogonal specifications, must be supported using the available middleware QoS classes. We also describe the experimental environment that will be used to refine the QoS mapping mechanisms.
To accommodate the requirements such as high usability and personalization of 4G (mobile) network... more To accommodate the requirements such as high usability and personalization of 4G (mobile) networks, conventional handheld single network-interface mobile devices are evolving into multihomed devices. Moreover, owing to the recent advances in the mobile middleware technologies, hardware technologies and association with the human user, handheld mobile devices are evolving into data producers and in turn acting as Nomadic Mobile Service (NMS) providers. For these devices, a vertical handover support is essential for the improved and reliable NMS delivery. Also, the fulfillment of the required QoS by the NMS is bounded by the end-to-end QoS (e2eQoS) provided by the underlying heterogeneous networks. To deal with these aspects, we propose a context-aware middleware architecture supporting vertical handover for the NMSs hosted on the handheld mobile devices. We emphasize the following features of the proposed middleware: 1) Context-aware computing based approach which uses an extensive set of context information collected from the mobile device and a fixed network; 2) Provisioning of and interaction with the end-to-end QoS (e2eQoS) predictions context source in the fixed network to obtain near-accurate estimation of the e2eQoS at a certain geographic location and to reduce unnecessary power usage in searching for available networks.
TINA '99. 1999 Telecommunications Information Networking Architecture Conference Proceedings (Cat. No.99EX368), 1999
One of the most spectacular developments of this decade is the enormous growth of the Internet. O... more One of the most spectacular developments of this decade is the enormous growth of the Internet. One of the most popular services of the Internet is the World Wide Web (WWW). It may be expected that the Web will be used to provide more sophisticated services, e.g., Video on Demand. Customers will be prepared to pay for such services, because of the exclusive content and the quality of the (broadband) transport network needed to transfer the information. Consequently, we need a way to manage these services, without violating the ease of use provided by current WWW. In this paper we present a solution based on TINA'S Business Model. We introduce Value Added Web (VAW), which is an integration of the WWW with TINA Service Management. This combination adds the benefits of the TINA Business Model to the WWW. A VAW session appears as a normal WWW session, except that it allows charging for specific content and the setup of connections with an agreed Quality of Service. The VAW Business Model assumes that users only have a direct relation with a Retailer and that the Retailer is responsible for charging. This paper describes the rationale behind VAW and the design and implementation of a prototype of VAW.
Lecture Notes in Computer Science, 2000
This paper presents an architecture for QoS-aware middleware platforms. We present a general fram... more This paper presents an architecture for QoS-aware middleware platforms. We present a general framework for control, and specialise this framework for QoS provisioning in the middleware context. We identify different alternatives for control, and we elaborate the technical issues related to controlling the internal characteristics of object middleware. We illustrate our QoS control approach by means of a scenario based on CORBA.
2007 IEEE Symposium on Computers and Communications, 2007
Nowadays, a variety ofhandheld mobile devices are capable of connecting to the Internet using mul... more Nowadays, a variety ofhandheld mobile devices are capable of connecting to the Internet using multiple network interfaces. This is referred to as multi-homing. In addition to this, enriched computation resources allow them to host nomadic mobile services and provide these services to the clients located anywhere in the Internet. Potential advantages of multi-homing for nomadic mobile services typically includes: an increased service availability and improved service performance. However, applications running on the handheld mobile devices either do not, or cannot, exploit multi-homing.
Fifth Annual IEEE International Conference on Pervasive Computing and Communications Workshops (PerComW'07), 2007
Context-awareness (CA) enables the development of personalized pervasive services. Current contex... more Context-awareness (CA) enables the development of personalized pervasive services. Current context-aware infrastructures focus on middleware solutions to support acquisition, usage and management of context. However, using context requires the CA application to create a binding between itself and one or more context producing entities. Creating this binding is the responsibility of the CA application developer, which is often an extensive manual task. The ad hoc availability of context-producing entities further complicates this responsibility. This paper proposes an application infrastructure, coined CACI, which offers a binding transparency to support rapid development of CA applications. CACI enables developers to specify context requirements at a high abstraction level using a declarative binding language. CACI also provides the creation and maintenance of bindings to context producing entities based on such specifications. This paper discusses the design and implementation of CACI. Additionally, it discusses the validation of CACI using a pervasive healthcare scenario.
Proceedings of the International Symposium on Distributed Objects and Applications, 1999
The CORBA layer in a distributed system hides the heterogeneity of the underlying computer networ... more The CORBA layer in a distributed system hides the heterogeneity of the underlying computer network. The interactions of objects located at different computing systems are described in terms of IDL specifications and the ORB takes care of the actual transfer of messages along the wire. In fact, an object interaction is translated into the transfer of GIOP messages over TCP/IP networks (IIOP). The advantages in terms of interoperability and portability are obvious. Currently, OMG is in the process of standardising the Open Communication Interface (OCI). Through OCI, a protocol module can be plugged into any ORB and hence, the distributed application including the ORB can be put on top of any network without changing the application's code, thus implementing network transparency. Obviously, the QoS of distributed applications depends on the QoS of the underlying network protocols, e.g., best effort versus guaranteed bandwidth. Through OCI we are able to use the network protocol that is needed to satisfy the QoS requirements of a specific distributed application. In this paper, we propose to extend CORBA with specialised protocols for QoS provisioning using OCI. We have prototyped protocol plug-in's, including a plug-in that exploits IP Multicast. The IP Multicast plug-in can be used in situations where one client communicates with a group of replicated servers. In fact, we have used this mechanism to implement replication transparency in CORBA. We have shown that the OCI interface can be used for QoS provisioning in CORBA. Based on our hands-on experience, we also have identified some shortcomings in the proposed OCI specification.
International Conference on Autonomic and Autonomous Systems (ICAS'06), 2006
and demonstrating context-aware applications is challenging. Gathering and using 'life' contextua... more and demonstrating context-aware applications is challenging. Gathering and using 'life' contextual information for these purposes, often requires significant extra development effort. Furthermore, repeating tests and demonstrations of context-aware applications that use 'life' context information, in a controlled way, is difficult or often impossible to achieve. This paper presents a context simulation framework, called SimuContext, which abstracts from the complexity of interfacing with physical context sources and facilitates testing and demonstrating context-aware applications in a controlled way.
Lecture Notes in Computer Science, 2004
This paper presents a Java service platform for mobile healthcare that enables remote health moni... more This paper presents a Java service platform for mobile healthcare that enables remote health monitoring using 2.5/3G public wireless networks. The platform complies with today's healthcare delivery models, in particular it incorporates some functionality of a healthcare call center, a healthportal for patients that aggregates healthcare services from collaborative care centers. Our service platform simplifies the development of mobile healthcare applications, because application developers are shielded from the complexity of communicating with mobile devices over 2.
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Papers by Aart Van Halteren