Cesare Stefanelli

Context-aware middleware for resource management in the wireless Internet

The provisioning of Web services over the wireless Internet introduces novel challenging issues for service design and implementation: from user/terminal mobility during service execution, to wide heterogeneity of portable access devices and unpredictable modifications in accessible resources. In this scenario, there are frequent provision-time changes in the context, defined as the logical set of accessible resources depending on client location, access terminal capabilities, and system/service management policies. The development of context-dependent services requires novel middlewares with full context visibility. We propose a middleware for context-aware resource management, called CARMEN, capable of supporting the automatic reconfiguration of wireless Internet services in response to context changes without any intervention on the service logic. CARMEN determines the context on the basis of metadata, which include declarative management policies and profiles for user preferences, terminal capabilities, and resource characteristics. In addition, CARMEN exploits the mobile agent technology to implement mobile middleware components that follow the provision-time movement of clients to support locally their customized service access. The proposed middleware shows how metadata and mobile agents can favor component reusability and automatic service reconfiguration, by reducing the development/ deployment complexity.

Mobile agent middleware for mobile computing

Mobile computing requires an advanced infrastructure that integrates suitable support protocols, mechanisms, and tools. This mobility middleware should dynamically reallocate and trace mobile users and terminals and permit communication and coordination of mobile entities. In addition, open and untrusted environments must overcome system heterogeneity and grant the appropriate security level. Solutions to these issues require compliance with standards to interoperate with different systems and legacy components and a reliable security infrastructure based on standard cryptographic mechanisms and tools. Many proposals suggest using mobile agent technology middleware to address these issues. A mobile agent moves entities in execution together with code and achieved state, making it possible to upgrade distributed computing environments without suspending service. We propose three mobile computing services: user virtual environment (UVE), mobile virtual terminal (MVT), and virtual resource management (VRM). UVE provides users with a uniform view of their working environments independent of current locations and specific terminals. MVT extends traditional terminal mobility by preserving the terminal execution state for restoration at new locations, including active processes and subscribed services. VRM permits mobile users and terminals to maintain access to resources and services by automatically requalifying the bindings and moving specific resources or services to permit load balancing and replication.

The ubiquitous provisioning of internet services to portable devices

Advances in mobile telecommunications and device miniaturization call for providing both standard and novel location- and context-dependent Internet services to mobile clients. Mobile agents are dynamic, asynchronous, and autonomous, making the MA programming paradigm suitable for developing novel middleware for mobility-enabled services.

A mobile computing middleware for location- and context-aware internet data services

The widespread diffusion of mobile computing calls for novel services capable of providing results that depend on both the current physical position of users (location) and the logical set of accessible resources, subscribed services, preferences, and requirements (context). Leaving the burden of location/context management to applications complicates service design and development. In addition, traditional middleware solutions tend to hide location/context visibility to the application level and are not suitable for supporting novel adaptive services for mobile computing scenarios. The article proposes a flexible middleware for the development and deployment of location/context-aware services for heterogeneous data access in the Internet. A primary design choice is to exploit a high-level policy framework to simplify the specification of services that the middleware dynamically adapts to the client location/context. In addition, the middleware adopts the mobile agent technology to effectively support autonomous, asynchronous, and local access to data resources, and is particularly suitable for temporarily disconnected clients. The article also presents the case study of a museum guide assistant service that provides visitors with location/context-dependent artistic data. The case study points out the flexibility and usability of the proposed middleware that permits automatic service reconfiguration with no impact on the implementation of the application logic.

Dynamic binding in mobile applications

By separating binding concerns from application logic, the Colomba approach exploits metadata to let mobile applications adapt to dynamic environments. Colomba separates service logic from binding management. This permits developers to code, change, and reuse service components and binding strategies independently of each other. Administrators can express binding strategies at a high level of abstraction in terms of declarative policies. In particular, Colomba supports a dynamic binding management that requires: Context awareness is the knowledge of application-specific attributes, such as user preferences, level of trust, subscribed services, and access device characteristics. Users can refer to a set of resources determined by context information. Location awareness is the knowledge of the physical position of the user or device connection to the network infrastructure. Available resources depend on location information.

An Open Secure Mobile Agent Framework for SystemsManagement

The Mobile Agent (MA) technology is gainingimportance in the distributed management of networks andservices for heterogeneous environments. MA-basedmanagement systems could represent an interestingalternative to traditional tools built upon theclient/server model, either SNMP- or CMIP-based. Twomain requirements currently limit the acceptance of MAsolutions for management: the need of interoperabilityand the request for security. Without security,management systems cannot suit global untrustedenvironments, such as the Internet; withoutinteroperability, they cannot interact with existingtools and legacy systems. The paper describes an MA-basedmanagement system with security and interoperability asthe two main design objectives. It is an open managementframework that grants interoperability by providing compliance with CORBA, the most diffusedstandard in the area of object-oriented components. Inaddition, it is based on a thorough security model andprovides a wide range of tools and mechanisms to build and enforce flexible securitypolicies.

Policy-Driven Management of Agent Systems

The agent paradigm has the potential to help in the development of applications for the open and heterogeneous Internet environment. Agents acting on the behalf of users can autonomously fulfil assigned goals, thus relieving users from complex and time-consuming tasks. Agent-based applications typically involve multiple agents, and each agent has to play a specific role that defines what the agent can and must do in order to achieve its application goal, and how it interacts with other agents and with the environment. This paper describes the integration of a policy language (Ponder) within an agent infrastructure (SOMA) in order to flexibly model agent roles and agent behaviour according to application specific requirements. The Ponder language is used to specify both agent permissions and duties and to model agent behaviour in terms of roles and relationships. SOMA is a rich infrastructure to support agent execution and provides a set of facilities that can help to build Ponder policy enforcement services. The integration of the two provides a flexible framework to the development and management of agent applications.

Security issues in mobile agent technology

The Mobile Agent (MA) paradigm seems to be a promising technology for developing applications in open, distributed and heterogeneous environments, such us the Internet. Many application areas, such as electronic commerce, mobile computing, network management and information retrieval can benefit from the application of the MA technology. The exploitation of mobile agents offer several peculiar advantages, such us reduction of network latency, asynchronous execution, robust and fault tolerant behavior. However, a wider diffusion of MA is currently limited by the lack of a comprehensive security framework that can address the security concerns arising in mobile agent applications providing efficiency at the same time. This paper describes an MA environment, called Secure and Open Mobile Agent (SOMA), that offers a wide range of security tools and mechanisms aimed at protecting both execution sites and agents against reciprocal malicious behavior. In particular, SOMA integrates several possible solutions to ensure agent integrity. The paper presents an electronic marketplace prototype based on SOMA where we have validated the efficiency and scalability of our security framework.

Mobile agents integrity for electronic commerce applications

Abstract The Mobile Agent (MA) paradigm proposes a new approach for designing applications in open and heterogeneous distributed environments. Several application areas can benefit from the adoption of the MA technology, because it can support electronic commerce transactions and help in information gathering, filtering, and negotiation. MA solutions provide mobility, autonomy and easy personalisation, but still lack a comprehensive and widely accepted security framework. Only a full answer to the requirement of protection for both execution sites and mobile shopping agents can leverage the adoption of MA solutions in the electronic commerce area. This paper proposes an MA environment to support secure and open electronic commerce applications. In particular, the paper focuses on how mobile shopping agents can be protected from malicious behaviour of execution sites and presents a range of solution strategies. The first solution makes use of a Trusted Third Party entity, while the second one is based on a distributed approach that does not assume the presence of trusted entities. In addition, these two solutions are integrated in a combined one. The paper compares the different approaches and describes their implementation performance.

Peer-to-peer communications for tactical environments: Observations, requirements, and experiences

Tactical edge networks present extremely challenging environments for communications given their wireless ad hoc nature and the inherent node mobility. Military applications such as Blue Force Tracking, inter-team communications, remote unmanned vehicle control, and sensor data mining/fusion thus have to deal with unstable links with limited bandwidth and variable latency. The peculiar characteristics of tactical networks call for peer-to-peer approaches to realize complex, adaptive, and fault-tolerant applications to be deployed in the battlefield. This article reports on our observations from several tactical networking experiments in which we have deployed state-of-the-art applications and services that leverage P2P communications. More specifically, we discuss why P2P approaches are critical for tactical network environments and applications. We then analyze the requirements that should be satisfied by P2P middleware for tactical environments. Finally, we discuss a case study, the Agile Computing Middleware, and present experimental results that demonstrate its effectiveness.