Showing papers on "Service abstraction published in 2008"

Service Abstraction Layer for UAV Flexible Application Development

Abstract: An Unmanned Aerial System (UAS) is an uninhabited airplane, piloted by embed- ded avionics and supervised by an operator on ground. Unmanned Aerial Systems were designed to operate in dangerous situations, like military missions. With the avionics tech- nological evolution, Unmanned Aerial Systems also become a valid option for commercial applications, specially for dull and tedious surveillance applications. Cost considerations will also deviate some mission done today with conventional aircrafts to Unmanned Aerial Systems. In order to build economically viable UAS solutions, the same platform should be able to implement a variety of missions with little reconfiguration time and overhead. This paper describes a software abstraction layer for a Unmanned Aerial System distributed architecture. The proposed abstraction layer allows the easy and fast design of missions and solves in a cost-effective way the reusability of the system. The distributed architecture of the Unmanned Aerial System is service oriented. Func- tional units are implemented as independent services that interact each other using commu- nication primitives in a network centric approach. The paper presents a set of predefined services useful for reconfigurable civil missions and the directives for their communication.

Composing semantic services in open sensor-rich environments

Abstract: Networked sensing promises to drastically change the way people interact with their environments by providing rich contextual information in real time. Major challenges remain on how concurrent users program and control such environments at the application level. This paper summarizes our research efforts in automatically composing semantics services to fulfill declarative user queries in resource efficient ways. We also describe an example software platform, MSR Sense, which supports service abstraction, composition, and execution.

Generating functional artifacts from low level design diagrams

Abstract: At least one design diagram is obtained from at least one previous software project. At least one service abstraction is extracted from the at least one design diagram. The at least one service abstraction is reused in a new software project. In another aspect, requirements are obtained for a current software project; at least one class diagram is obtained from at least one previous software project; a dependency graph is generated from the at least one design diagram, using link analysis; relationships between classes in the dependency graph are analyzed to obtain functional artifacts for the requirements; and the functional artifacts are reused in the new software project.

Modular exposure of next generation network services to enterprises and testbed federations

Abstract: This paper describes how next generation network and IP multimedia subsystem services provided by Telco networks as well as testbeds and testbed federations can be used in a modular fashion to compose high level multimedia services The IP multimedia subsystem, specified by the 3rd generation partnership projects (3GPP and 3GPP2), was developed to address next generation network convergence challenges and end-user requirements As an all-IP overlay network architecture, it aims at providing a platform for provisioning services in a secure and controllable manner, merging the paradigms and technologies of the Internet with the cellular and fixed telecommunication worlds and was also adopted for the Next generation network architecture of ETSI TISPAN In this paper we will outline the requirements on service description, service discovery and service orchestration in next generation networks and distributed testbed environments We will further describe how to make use of service building blocks to expose network functionalities towards higher service abstraction layers We will finally display our findings in the light of the Open SOA Telco Playground, one of the Fraunhofer FOKUS testbeds that represents today a first approach to the practical implementation of the ideas described

The Role of Service Abstraction and Service Variability and Its Impact on Requirements Engineering for Service-Oriented Systems

Abstract: The service-oriented paradigm typically separates the development of systems into service engineering and application engineering. In our opinion, these two disciplines cannot be completely separated, as otherwise, there is no assurance that services provided by service engineering can actually be used by application engineering. In this paper, we describe service-oriented requirements engineering (SORE) as an appropriate means for mediating between the two disciplines, and we identify the provision of service capabilities on the right level of abstraction and variability as the most crucial aspects SORE has to assure. For this purpose, we present the adoption of product line technology in service- oriented architecture and its closer alignment with business process management as a promising approach, and list related principles as well as challenges we plan to address in our ongoing research.

Promoting Reuse via Extraction of Domain Concepts and Service Abstractions from Design Diagrams

Abstract: Systematic reuse of software artifacts has been an elusive goal for several years. Service-oriented architecture (SOA) has been touted in recent years due its promise of fostering reuse. Even so, reuse with SOA continues to be limited due to the lack of formal techniques for extracting domain knowledge from existing reusable software assets. In this paper,we present an approach that extracts the domain knowledge and service abstractions from design diagrams of existing software solutions and represents it in a form that can be reused in new projects. We have implemented our approach and preliminary results indicate that both domain knowledge and service abstraction thus extracted can promote reuse of software assets to a large extent.

Service Oriented Architecture – Overview of Technologies and Standards

Abstract: In constantly changing and dynamic markets enterprises are in an even greater need to maintain adequate IT support for their core competencies. This support requires integrating heterogeneous systems and applications that are built using different technologies and infrastructures, which hamper interoperability and seamless integration. The problems are aggravated additionally by the need to cross enterprise boundaries and the necessity to react to changes in that same environment in an ad-hoc manner. Service-oriented computing (SOC) provides a powerful abstraction basically allowing to perceiving all compute resources as entities that can be dynamically discovered and composed. These entities are called services in SOC: a service is exposed for use over a network, and it is always ready for use. Services are described in terms of interfaces specifying service functionality independent of platform technology or programming language used. This renders the service abstraction particularly advantageous when applied for tackling problems due to heterogeneity of IT landscapes. Service oriented architecture (SOA) is the accompanying architectural style. The roles in the SOA are: service provider, service consumers and service registry. Applications compliant with the SOA can be implemented in terms of various technologies and programming languages. Services communicate through messaging and are loosely coupled. The single technology that has been created to implement SOA inherently and from its onset is the Web service technology. It provides an abstract component model for representing and using services. Based on the heterogeneity and interoperability problems to solve, this technology is highly dependent on standardization; it enables reuse of legacy applications and aims at solving integration problems. The Web Service technology defines a stack of composable specification addressing orthogonal concerns that can be easily composed to meet the requirements of various application domains. Web services are the only service-oriented technology that has enjoyed a tremendous success in acceptance by industry and academia. The implication of its composable nature is that the execution infrastructure for service-oriented applications must support that composability of protocols. Web services mainly target machine-to-machine interaction, which is driven by the need to enable high degree of automation. The execution infrastructure for such applications is referred to as (Enterprise) Service Bus (ESB). It is a piece of middleware enabling the application of the concepts of service orientation. The papers in this issue of it give an overview of the most important aspects of SOA from the point of view of both, industry and academia. The paper of Dustdar and Papazoglou provides definitions of what services and composite services are and illustrates the basic principles of service-oriented computing and how they are reflected by the Web service technology. The distinguishing differences between Web services and other programming models are discussed. This overview paper compares the provision of enterprise solutions using the application service provider (ASP) model and the service-oriented computing approach, whereas the major benefit of services is revealed by their

A Generic Service Oriented Architectural Model for Pervasive Applications: A Case Study in Internet-based Multiple Robot Control

Abstract: This paper introduces a generic service oriented architectural model which can be employed for various classes of pervasive computing applications. The utility of the model is demonstrated with respect to its successful application in an Internet-based control system for multiple robots. A service abstraction technique is also introduced for describing groups of services which provide similar functionality.

Business-Oriented Virtualization of Web Services A Case Study

Abstract: In addition to enabling controlled sharing and isolation, the virtualization mechanism can help to provide users a single image, and to realize a more abstract and uniform view from a set of fine-grained, heterogeneous and un-ordered instances. The paper explores ways of business-oriented service abstraction, Web service virtualization, presents a practical approach and discusses the effects thereof in an e-science environment for bioinformatics research.

Ontology-based service layering for facilitating alternative service discovery

Abstract: To provide dynamic services for users in a ubiquitous environment, an efficient context-aware service discovery mechanism is essential. Most of current researches are focused on composing services which satisfy pre-defined service specifications, by checking the availability of the devices and finding services that satisfy the user's preference. In this paper, we introduce a process for building a ubiquitous service ontology, and propose the specification to describe each service. With the service ontology, using the concept of service availability, not device availability, our method could discover the most appropriate service, and replace of it if the service requested is unavailable. The experimental result shows that our service ontology for home domain could reduce, on the average, more than 36% of the time required to discover alternative services compare to using just a flat list of services.

An Architecture for the seamless integration of UAV-based wildfire monitoring missions

Abstract: Current Unmanned Aerial Vehicles (UAVs) technology offers feasible technical solutions for airframes, flight control, communications, and base stations. In addition, the evolution of technology is miniaturizing most sensors used in airborne applications. Hence, sensors like weather radars, SAR, multi spectral line-scan devices, etc. in addition to visual and thermal cameras are being used as payload on board UAVs. As a result (UAVs) are slowly becoming efficient platforms that can be applied in scientific/commercial remote sensing applications. UAVs may offer interesting benefits in terms of cost, flexibility, endurance, etc. Even remote sensing in dangerous situations due to extreme climatic conditions (wind, cold, heat) are now seen as possible because the human factor on board the airborne platform is no longer present. However, the complexity of developing a full UAV-system tailored for remote sensing is currently limiting its practical application. Currently, only large organizations like NASA or NOAA have enough resources and infrastructure to develop such applications. Even though the rapid evolution of UAV technology the generalized development of remote sensing applications is still limited by the absence of systems that support the development of the actual UAV sensing mission. Remote sensing engineers face the development of specific systems to control their desired flight-profile, sensor activation/confi guration along the flight, data storage and eventually its transmission to the ground control. All these elements may delay and increase the risk and cost of the project. This work introduces a flexible and reusable architecture designed to facilitate the development of UAV-based remote sensing applications. Applications are developed following a service/subscription based software architecture. Each computation module may support multiple applications. Each application could create and subscribe to available services. Services could be discovered and consumed in a dynamic way like web services in the Internet domain. Applications could interchange information transparently from network topology, application implementation and actual data payload. This flexibility is organized into an user-parameterizable UAV service abstraction layer (USAL). The USAL defines a collection of pre-defined services and their interrelations as a basic starting point for further development by users. Functionalities like enhanced flight-plans, mission control, data storage, communications management, etc. are offered. Additional services can be included according to requirements but all existing services and inter-service communication infrastructure can be exploited and tailored to specific needs. This approach reduces development times and risks, but at the same time gives the user higher levels of flexibility and permits the development of more ambitious applications. As application scenario, we are developing a UAV system devoted to the detection, control and analysis of wildland forest fires in the Mediterranean area. The design of the proposed UAV system is composed of five main components. Each component will work collaboratively to constitute a platform of high added value.

AutoNav4D. A co-simulator for unmanned aircraft systems

Abstract: This TFC document shows the requirements and the components needed to integrate in the same scenario, real Unmanned Aircraft Systems (UAS) and simulated systems. This is called co-simulation. An UAS is a series of onboard avionics systems and an on ground platform, which might takeoff, fly a mission and land safe without a human intervention. UAS Service Abstraction Layer (USAL) is a set of available services running on top of the UAV system architecture to give support to most types of civil UAS missions. These services are managed and communicated by a thin software layer called Architecture for Remote Embedded Applications (MAREA). This Middleware promotes a publish/subscribe model for sending and receiving data, events and commands among the services of the UAS. The Icarus Simulation Integrated Scenario (ISIS) is a collection of reusable services that comprises a minimum common set of elements that are needed in most UAV missions. Some of these services conform the co-simulator. This ISIS integrated scenario is useful to test the platform before the UAS flies. The ICARUS team has developed his Service Oriented Architecture (SOA) platform where is set the real UAS. The co-simulator is an Open Architecture. It may have a Visor Service, some Virtual Vehicles and Virtual Services and a Manager of Virtuality. This co-simulator gives capabilities in fast prototyping and simulation to the UAS Service Abstraction Layer (USAL). Fast prototyping is reached by the use of standards and components. It allows a fast design and implementation of new functionalities. Simulation is used for increase safety and reduce design cost. When a service abstraction layer is used, a virtual implementation has similar effects like the real ones. My job for this TFC was to design and to implement some solutions which conform a co-simulator for Unmanned Aircraft Systems. This co-simulator has been called AutoNAV4D93. There are many things to add to the co-simulator and it may be accomplished in a future as a result of ISIS developing work. The ISIS integrated scenarios will be presented in the AIAA’09 Meeting and exhibit in 9 of January 2009.

Exploiting host availability in distributed systems

Abstract: As distributed systems become more decentralized, fluctuating host availability is an increasingly disruptive phenomenon. Older systems such as AFS used a small number of well-maintained, highly available machines to coordinate access to shared client state; server uptime (and thus service availability) were expected to be high. Newer services scale to larger number of clients by increasing the number of servers. In these systems, the responsibility for maintaining the service abstraction is spread amongst thousands of machines. In the extreme, each client is also a server who must respond to requests from its peers, and each host can opt in or out of the system at any time. In these operating environments, a non-trivial fraction of servers will be unavailable at any give time. This diffusion of responsibility from a few dedicated hosts to many unreliable ones has a dramatic impact on distributed system design, since it is difficult to build robust applications atop a partially available, potentially untrusted substrate. This dissertation explores one aspect of this challenge: how can a distributed system measure the fluctuating availability of its constituent hosts, and how can it use an understanding of this churn to improve performance and security? This dissertation extends the previous literature in three ways. First, it introduces new analytical techniques for characterizing availability data, applying these techniques to several real networks and explaining the distinct uptime patterns found within. Second, this dissertation introduces new methods for predicting future availability, both at the granularity of individual hosts and clusters of hosts. Third, my dissertation describes how to use these new techniques to improve the performance and security of distributed systems.