Actions and Events in Concurrent Systems Design

In this work, having in mind the construction of concurrent systems from components, we discuss the difference between actions and events. For this discussion, we propose an(other) architecture description language in which actions and events are made explicit in the description of a component and a system. Our work builds from the ideas set forth by the categorical approach to the construction of software based systems from components advocated by Goguen and Burstall, in the context of institutions, and by Fiadeiro and Maibaum, in the context of temporal logic. In this context, we formalize a notion of a component as an element of an indexed category and we elicit a notion of a morphism between components as morphisms of this category. Moreover, we elaborate on how this formalization captures, in a convenient manner, the underlying structure of a component and the basic interaction mechanisms for putting components together. Further, we advance some ideas on how certain matters related to the openness and the compositionality of a component/system may be described in terms of classes of morphisms, thus potentially supporting a compositional rely/guarantee reasoning.Comment: In Proceedings LAFM 2013, arXiv:1401.056

Architecture Description for Mobile Distributed Systems

In this paper we motivate an Architecture Description Language (ADL) for mobile distributed systems based on the π-calculus. Different from other approaches, the non-functional properties, which are essential when mobile architectures are described, are treated in a flexible manner by inserting logical formulae for expressing and checking non-functional properties into π-calculus processes. A formal example is given to illustrate the approach before the constituents of the ADL are sketched

Modellierung und Analyse mobiler Architekturen

Das Verhalten eines mobilen Systems wird bestimmt durch seine Architektur (statische und dynamische Anteile, Softwareverteilung), die zu Grunde liegende Netzwerkinfrastruktur (Topologie, Parameter wie Bandbreiten oder Latenzzeiten) und Interaktionen der Benutzer mit dem System. Um bereits zur Entwurfszeit zu bestimmen, ob ein mobiles System nichtfunktionale Anforderungen wie Antwortzeiten oder Verfügbarkeit von Diensten erfüllt, kann eine Simulation des Systems auf Basis eines Architekturmodells unter Einbeziehung eines Netzwerk- und eines Benutzerinteraktionsmodells durchgeführt werden. Ein derartiger Ansatz unter Verwendung der Architekturbeschreibungssprache Con Moto wird in diesem Beitrag vorgestellt

Software architecture: styles and representational schemes

Software architecture is being widely used today to describe a very high-level design methodology of large software systems. Software architecture represents the overall structure of a system in an abstract, structured manner. A good architectural representation scheme holds the key to the effectiveness of a software architecture description and usage. In this work we look at architectural styles and architectural representation schemes. We propound the idea that the layered architectural model is a suitable candidate for a generalized architectural style and that it can cater to many different problem domains, other than the message-passing systems it has traditionally been used to model. We propose some rules by which the layered architectural style can be improved and modified in order to be able to model a wider problem domain. Then we evaluate different methods of architectural representations that have been used to model software architecture and analyze their strengths and shortcomings. We propose the use of a modified data flow diagram architecture representation scheme. This scheme is called AND-OR DFD method and is introduced and developed in this thesis. The main concept introduced here is a combination of components to form action groups to support multiple workflows and the relationships among them, without significant increase in the architectural complexity. Finally, we look at UML as a prospect for a generalized architecture description language and discuss its merits and demerits with examples

リソースに基づく代数的アーキテクチャモデルのプロセス代数CCSによる実装について

近年, システムの高分散化に伴い, ソフトウェアアーキテクチャを構成する上で, コンポーネント間のデータ転送方式の選択の重要性が高まってきている. データの転送方式は大きくPUSH型とPULL型に分けることができるが, いずれのデータ転送方式を採用するかが, システム全体の最終的な性能に大きな影響を及ぼす. そのため, 開発の初期の段階で適切にデータ転送方式を評価できることが望まれる.一般にアーキテクチャ設計を正しく評価するためには, アーキテクチャの設計内容を厳密に定義できる体系が必要となる. そのため, アーキテクチャモデル及びアーキテクチャ記述言語の研究が広く行われてきた. 本研究室では, データ転送方式の選択および評価の支援を目的とした代数的アーキテクチャモデルの提案を行っている. 提案アーキテクチャモデルは, 制御の流れに関する情報を捨象することによって, プロセス代数などのプロセスに基づく他の記述体系よりも抽象度の高い情報を記述することを可能にしている. そのため, 提案アーキテクチャモデルによって記述されたアーキテクチャ情報は, データ転送方式の選択の影響を受けないという特徴を持つ.本論文では, 既存の記述体系としてプロセス代数CCS を選び, 提案アーキテクチャモデルの記述から, データ転送方式の選択に応じてCCS による実装を自動生成できることを示し, 生成されたCCS 実装が元のアーキテクチャモデルと等価となることを証明する. また, 等価性を保ちながらデータ転送方式を変更するための十分条件を示す. これらによって, 提案アーキテクチャモデルに基づいてデータ転送方式をリファクタリングするための理論的な基盤の構築が可能となる

SAVCBS 2005 Proceedings: Specification and Verification of Component-Based Systems

This workshop is concerned with how formal (i.e., mathematical) techniques can be or should be used to establish a suitable foundation for the specification and verification of component-based systems. Component-based systems are a growing concern for the software engineering community. Specification and reasoning techniques are urgently needed to permit composition of systems from components. Component-based specification and verification is also vital for scaling advanced verification techniques such as extended static analysis and model checking to the size of real systems. The workshop will consider formalization of both functional and non-functional behavior, such as performance or reliability. This workshop brings together researchers and practitioners in the areas of component-based software and formal methods to address the open problems in modular specification and verification of systems composed from components. We are interested in bridging the gap between principles and practice. The intent of bringing participants together at the workshop is to help form a community-oriented understanding of the relevant research problems and help steer formal methods research in a direction that will address the problems of component-based systems. For example, researchers in formal methods have only recently begun to study principles of object-oriented software specification and verification, but do not yet have a good handle on how inheritance can be exploited in specification and verification. Other issues are also important in the practice of component-based systems, such as concurrency, mechanization and scalability, performance (time and space), reusability, and understandability. The aim is to brainstorm about these and related topics to understand both the problems involved and how formal techniques may be useful in solving them

Models, services and security in modern online social networks

Modern online social networks have revolutionized the world the same way the radio and the plane did, crossing geographical and time boundaries, not without problems, more can be learned, they can still change our world and that their true worth is still a question for the future