Naming and discovery in networks : architecture and economics

In less than three decades, the Internet was transformed from a research network available to the academic community into an international communication infrastructure. Despite its tremendous success, there is a growing consensus in the research community that the Internet has architectural limitations that need to be addressed in a effort to design a future Internet. Among the main technical limitations are the lack of mobility support, and the lack of security and trust. The Internet, and particularly TCP/IP, identifies endpoints using a location/routing identifier, the IP address. Coupling the endpoint identifier to the location identifier hinders mobility and poorly identifies the actual endpoint. On the other hand, the lack of security has been attributed to limitations in both the network and the endpoint. Authentication for example is one of the main concerns in the architecture and is hard to implement partly due to lack of identity support. The general problem that this dissertation is concerned with is that of designing a future Internet. Towards this end, we focus on two specific sub-problems. The first problem is the lack of a framework for thinking about architectures and their design implications. It was obvious after surveying the literature that the majority of the architectural work remains idiosyncratic and descriptions of network architectures are mostly idiomatic. This has led to the overloading of architectural terms, and to the emergence of a large body of network architecture proposals with no clear understanding of their cross similarities, compatibility points, their unique properties, and architectural performance and soundness. On the other hand, the second problem concerns the limitations of traditional naming and discovery schemes in terms of service differentiation and economic incentives. One of the recurring themes in the community is the need to separate an entity\u27s identifier from its locator to enhance mobility and security. Separation of identifier and locator is a widely accepted design principle for a future Internet. Separation however requires a process to translate from the identifier to the locator when discovering a network path to some identified entity. We refer to this process as identifier-based discovery, or simply discovery, and we recognize two limitations that are inherent in the design of traditional discovery schemes. The first limitation is the homogeneity of the service where all entities are assumed to have the same discovery performance requirements. The second limitation is the inherent incentive mismatch as it relates to sharing the cost of discovery. This dissertation addresses both subproblems, the architectural framework as well as the naming and discovery limitations

A Model of Layered Architectures

Architectural styles and patterns play an important role in software engineering. One of the most known ones is the layered architecture style. However, this style is usually only stated informally, which may cause problems such as ambiguity, wrong conclusions, and difficulty when checking the conformance of a system to the style. We address these problems by providing a formal, denotational semantics of the layered architecture style. Mainly, we present a sufficiently abstract and rigorous description of layered architectures. Loosely speaking, a layered architecture consists of a hierarchy of layers, in which services communicate via ports. A layer is modeled as a relation between used and provided services, and layer composition is defined by means of relational composition. Furthermore, we provide a formal definition for the notions of syntactic and semantic dependency between the layers. We show that these dependencies are not comparable in general. Moreover, we identify sufficient conditions under which, in an intuitive sense which we make precise in our treatment, the semantic dependency implies, is implied by, or even coincides with the reflexive-transitive closure of the syntactic dependency. Our results provide a technology-independent characterization of the layered architecture style, which may be used by software architects to ensure that a system is indeed built according to that style.Comment: In Proceedings FESCA 2015, arXiv:1503.0437

A Conceptual Architecture for Enabling Future Self-Adaptive Service Systems

Dynamic integration methods for unknown data sources and services at system design time are currently primarily driven by technological standards. Hence, little emphasis is being placed on integration methods. However, the combination of heterogeneous data sources and services offered by devices across domains is hard to standardize. In this paper, we will shed light on the interplay of self-adaptive system architectures as well as bottom-up, incremental integration methods relying on formal knowledge bases. An incremental integration method has direct influences on both the system architecture itself and the way these systems are engineered and operated during design and runtime. Our findings are evaluated in the context of a case study that uses an adapted bus architecture including two tool prototypes. In addition, we illustrate conceptually how control loops such as MAPE-K can be enriched with machine-readable integration knowledge

The role of use cases in development of a reference framework for interoperability of data exchange in agriculture

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Towards a semantic event-based service-oriented architecture

Service-Oriented Architecture (SOA) is commonly lauded as a silver bullet for Enterprise Application Integration, inter-organizational business processes implementation, and even as a general solution for the development of all complex Web-oriented applications. However, SOA without semantic descriptions of its data, processes and messaging models fails to achieve a truly flexible and dynamic infrastructure. In this paper we explain where semantics are necessary for SOA and present early work on a Semantic Execution Environment which couples the ServiceOriented and Event-Driven architecture styles with formal semantics

Reverse-engineering of architectural buildings based on an hybrid modeling approach

We thank MENSI and REALVIZ companies for their helpful comments and the following people for providing us images from their works: Francesca De Domenico (Fig. 1), Kyung-Tae Kim (Fig. 9). The CMN (French national center of patrimony buildings) is also acknowledged for the opportunity given to demonstrate our approach on the Hotel de Sully in Paris. We thank Tudor Driscu for his help on the English translation.This article presents a set of theoretical reflections and technical demonstrations that constitute a new methodological base for the architectural surveying and representation using computer graphics techniques. The problem we treated relates to three distinct concerns: the surveying of architectural objects, the construction and the semantic enrichment of their geometrical models, and their handling for the extraction of dimensional information. A hybrid approach to 3D reconstruction is described. This new approach combines range-based modeling and image-based modeling techniques; it integrates the concept of architectural feature-based modeling. To develop this concept set up a first process of extraction and formalization of architectural knowledge based on the analysis of architectural treaties is carried on. Then, the identified features are used to produce a template shape library. Finally the problem of the overall model structure and organization is addressed

Extended enterprise architecture with the FADEE.

Business-to-Business integration (B2Bi) is considered to be not merely an IT-issue, but also a business problem. This paper draws attention to the challenges companies within an Extended Enterprise are confronted with when integrating their systems. We primarily pay attention to coordination problems that may arise. To overcome these problems we propose the use of Enterprise Architecture descriptions. We discuss the powers of using Enterprise Architecture descriptions in integration exercises. It will become clear that doing Enterprise Architecture is no longer an option; it is mandatory. Furthermore, we present the FADEE, the Framework for the Architectural Description of the Extended Enterprise. This framework gives an overview of how companies can apply the Zachman framework to do Enterprise Architecture in the realm of the Extended Enterprise.Architecture; Business-to-Business integration; Companies; Coordination; Enterprise architecture; Extended enterprise; Extended enterprise architecture framework; FADEE; Framework; Integration; Problems; Research; Systems;

Quality-aware model-driven service engineering

Service engineering and service-oriented architecture as an integration and platform technology is a recent approach to software systems integration. Quality aspects ranging from interoperability to maintainability to performance are of central importance for the integration of heterogeneous, distributed service-based systems. Architecture models can substantially influence quality attributes of the implemented software systems. Besides the benefits of explicit architectures on maintainability and reuse, architectural constraints such as styles, reference architectures and architectural patterns can influence observable software properties such as performance. Empirical performance evaluation is a process of measuring and evaluating the performance of implemented software. We present an approach for addressing the quality of services and service-based systems at the model-level in the context of model-driven service engineering. The focus on architecture-level models is a consequence of the black-box character of services