Elmar Zeeb

Service-Oriented Architectures for Embedded Systems Using Devices Profile for Web Services

A movement from distributed systems controlled by users to automatic, autonomous and self-configuring distributed systems is noticeable. Web services is one approach but lacking the secure integration of resource-constraint devices. This paper describes the devices profile for Web services (DPWS), underlying protocols and a DPWS toolkit implementation based on C and gSOAP and discuss its current state. It has enormous relevance for embedded systems and industrial automation since DPWS targets resource-constraint devices explicitly, and has the potential to shift the industrial landscape which is characterized of heterogeneous devices.

WS4D: Toolkits for Networked Embedded Systems Based on the Devices Profile for Web Services

As the application of the Internet Protocol (IP) is not longer restricted to the internet and computer networks, future IP-based application scenarios require an enormous diversity of heterogeneous platforms and systems. Thereby emerging communication architectures, concepts, technologies and protocols must be capable of handling thousands of devices and communication endpoints on the one hand and be flexible and extensible enough on the other hand, to provide cross domain interoperability independent of platform specific constraints. The Devices Profile for Web Services (DPWS) is such a cross domain technology. This paper provides an overview of DPWS and existing DPWS implementations and toolkits with special focus on the Web Service for Devices (WS4D) initiative. Therefore, features and capabilities of DPWS are described in detail by referring to the open source WS4D implementations. The target platforms are ranging from resource rich server platforms down to highly resource constrained embedded devices.

Devices Profile for Web Services in Wireless Sensor Networks: Adaptations and enhancements

For Service-oriented Architectures, Web Services are claimed as state of the art to connect business execution layers as well as networking devices. Additionally, the deployment of Wireless Sensor Networks became applicable over the last years. The usage of application layer gateways and proxy concepts allow the integration of these sensor networks into real world scenarios and existing networks that make use of Web Services. This paper presents a new approach to adapt and enhance the Devices Profile for Web Services to be applied in Wireless Sensor Networks directly. Thus, seamless connectivity between business layers, device level networks, and Wireless Sensor Networks are possible.

Implementing powerful Web Services for highly resource-constrained devices

Web Service technologies are state of the art in current enterprise distributed applications. To integrate highly resource-constrained devices, such as sensor nodes, into enterprise applications via Web Services, gateways are commonly used. Our aim was to investigate the intermediate, homogeneous communication between enterprise applications and highly resource-constrained devices. We therefore present the prototype implementation of an embedded enterprise compatible W3C Web Service solution. Furthermore, we give an evaluation of memory requirements and a timing analysis for a representative platform with 48 KiB of ROM, 10 KiB of RAM and IEEE 802.15.4 radio. As the prototype implementation requires only 8:5 KiB of ROM and 3 KiB of RAM, our results claim that enterprise Web Services, despite of prevailing assumptions, are feasible in this context.

Lessons learned from implementing the Devices Profile for Web Services

In recent years a movement from distributed systems controlled by users to automatic, autonomous and self-configuring distributed systems is noticeable. Web services is one approach but lacking the secure integration of resource-constrained devices. This paper describes the devices profile for web services (DPWS), underlying protocols and a DPWS toolkit implementation based on C and gSOAP and discusses its current state. It has enormous relevance for embedded systems and industrial automation since DPWS targets resource-constraint devices explicitly, and has the potential to shift the industrial landscape which is characterized of heterogeneous devices.

Web Services to improve interoperability of home healthcare devices

Home healthcare can be divided into monitoring and assistance scenarios. In both scenarios, miscellaneous devices are applied for dedicated sensor or actuator functionalities. The requirements and assumptions for the different nodes split the devices in three different classes with particular characteristics concerning energy consumption, power supply, memory, computing power, and bandwidth. Nevertheless, the number of nodes and complexity of setups require new concepts like Service-oriented Architectures to solve arising problems. In this paper, the Devices Profile for Web Services is suggested as comprehensive middleware for all three device classes. Hence, Web services technologies, which are already applied in the internet and in automation industry, can avoid interoperability problems of sensors and actors in the domain of home healthcare also.

Devices Profile for Web Services and the REST

For future application scenarios of resource constrained and low cost smart cooperating objects, miscellaneous technologies for wireless connectivity are existing or upcoming in the near future. But further cross domain middleware and dedicated communication protocols to provide syntactic and semantic interoperability and not only technical interoperability are still missing. Thus, this paper investigates on two major candidates for IP based low power communication, based on known and matured technologies and protocols. Therefore, analyses and pitfalls of RESTful architectures based on HTTP and the Devices Profile for Web Services are presented. Furthermore, the paper discusses differences of DPWS and RESTful design and furthermore proposes an approach for a generic mapping of emerging Bluetooth Low Energy technology with RESTful device architectures for seamless and transparent connectivity.

OSAMI-D: An open service platform for healthcare monitoring applications

In this paper conceptions and architectural considerations of the OSAMI project and their specializations towards the requirements of the e-health domain by the German subproject (OSAMI-D) are described. Along with the expected shift of healthcare service between stationary towards ambulatory care, a standardized way of integrating medical data acquired at home into the IT infrastructure of hospitals and the synchronization with medical workflows have to be implemented. Therefore, the OSAMI-D project will provide open source components that implement the required interfaces. Preliminary results of the requirements analysis and the implementation of first domain-specific services are presented. These services are used to realize two home care scenarios, which support ambulant cardiologic rehabilitation (indoor and outdoor). Special emphasis is placed on standards and formats for the communication and storage of patient data.

A distributed object system approach for dynamic reconfiguration

Managing reconfigurable hardware resources at runtime is expected to be a new task for future operating systems. But due to the mixture of parallel and sequential parts of dynamically reconfigurable applications, it is not entirely clear so far, how to use and to program such systems. A new interpretation of dynamically reconfigurable applications is presented. It is shown, that the parallel computing concept of distributed object systems may be adapted for dynamically reconfigurable architectures. This approach answers many open questions concerning communication, interruption, and relocation of reconfigurable modules. It is explored by means of an extended Linux operating system in conjunction with a SystemC model of a dynamically reconfigurable FPGA

Applicability of Web Service Technologies to Reach Real Time Capabilities

Currently the developing process for enterprise applications is improved by the service oriented architecture (SOA) paradigms. With SOAs the creation of modular and clearly defined software architectures at a high grade of interoperability and reusability is possible. For resource- constraint networked devices the devices profile for Web services (DPWS) specification adapt the SOA paradigms to create a framework for interoperable and standardized communication between embedded devices. This paper explains how special parts of DPWS can be adapted to provide real-time capabilities. So this paper shows how developers of real-time software can use the advantages of Web services and which adaptations are necessary to create Web services with real-time capabilities.