Forming telecommunications software specifications from a service-driven model using enhanced software tools

Increasing diversity and sophistication among telecommunications customers has led to pressure on the telecommunications industry to give customer groups the capability to customize aspects of offered telecommunications services for their own particular needs. To offer such user-customizable services correctly, quickly, and cheaply, the telecommunications industry needs adequate techniques for transforming user requirements into software specifications and for realizing these software specifications with application code. In today's environment, several well-known software development life cycle processes exist for realizing software specifications; however, analogous techniques for transforming user requirements into explicit software specifications do not. This paper proposes a technique for transforming user requirements and then demonstrates its use on a sample telecommunications application. The technique creates a simulation environment that lets simulation users describe their application requirements and then determine the appropriate software specifications needed. The technique builds on aspects of a service-driven specification model and simulation software tools published earlier. Because the simulation environment derives from user requirements and produces software specifications, the proposed technique could represent the first phase of a service-driven software development life cycle process, eventually evolving from the nonservice-driven “requirements analysis” phase commonly used in practice today.     

User interface specification with sequence diagrams: an application to the AIRBUS A380 Datalink system

The development of user interfaces for safety critical systems is driven by requirements specifications. Because user interface specifications are typically embedded within complex systems requirements specifications, they can be intractable to manage. Proprietary requirements specification tools do not support the user interface designer in modelling and specifying the user interface. In this paper, a new way of working with embedded user interface specifications is proposed, exploiting sequence diagrams with a hypertext structure for representing and retrieving use cases. This new tool concept is assessed through an application to the requirements specification for the Airbus A380 air traffic control Datalink system; engineers involved in the development of the Airbus cockpit used a prototype of the tool concept to resolve a set of user interface design anomalies in the requirements specification. The results of the study are positive and indicate the user interface to requirements specification tools which user interface designers themselves need.     

Synthesizing structured analysis and object‐based formal specifications

Structured Analysis (SA) is a widely‐used software development method. SA specifications are based on Data Flow Diagrams (DFD's), Data Dictionaries (DD's) and Process Specifications (P‐Specs). As used in practice, SA specifications are not formal. Seemingly orthogonal approaches to specifications are those using formal, object‐based, abstract model specification languages, e.g., VDM, Z, Larch/C++ and SPECS. These languages support object‐based software development in that they are designed to specify abstract data types (ADT's). We suggest formalizing SA specifications by: (i) formally specifying flow value types as ADT's in DD's, (ii) formally specifying P‐Specs using both the assertional style of the aforementioned specification languages and ADT operations defined in DD's, and (iii) adopting a formal semantics for DFD “execution steps”. The resulting formalized SA specifications, DFD‐SPECS, are well‐suited to the specification of distributed or concurrent systems. We provide an example DFD‐SPEC for a client‐server system with a replicated server. When synthesized with our recent results in the direct execution of formal, model‐based specifications, DFD‐SPECS will also support the direct execution of specifications of concurrent or distributed systems.     

ASADAL/SIM: an incremental multi-level simulation and analysis tool for real-time software specifications

Despite considerable advancement in software engineering methods during the past three decades, requirements engineering of large and complex software systems still remains a difficult and active research problem. One such difficulty lies in developing correct and useful methods for the validation and verification of real-time software specifications. One way of analyzing and validating/verifying software specifications is to mathematically derive or prove desired system properties based on formal specification languages. A full scale system analysis using such formal methods is limited in practice because of the required mathematical skills and computational costs. Formal methods are often used to check only a few very critical real-time properties. Simulation is a complementary approach to testing various system characteristics and validating user requirements. It is especially good for providing a rough picture of final system behavior. This paper presents ASADAL/SIM, a tool for multi-level simulation and analysis of real-time software specifications. It is a subsystem of a larger computer-aided real-time software development environment called ASADAL, and complements ASADAL/PROVER, another subsystem of ASADAL which is a formal verification module.^1. With ASADAL/SIM, simulation primitives can be added to evolving specifications in order to assign stochastic behaviors to external entities and internal processes, and to build a simulation model. ASADAL/SIM can execute the model and, at the same time, demonstrate the final system behavior by graphically showing internal workings of the system; catch undesirable system behaviors with breakpoints; and present various analytical results and system statistics ASADAL/SIM, following ASADAL's philosophies of hierarchical system modeling and early system validation, allows users to simulate ‘evolving’ specifications at different, mixed, and wide levels of detail. In particular, algorithmic details may be specified for low level behavioral blocks, and simulated with abstract entities yet to be refined to such a level. This facilitates the tracking of critical data values at the specification level, and eases the next transformation into code level implementation. With ASADAL/SIM, ASADAL becomes an effective and comprehensive supporting tool for various existing software engineering approaches, particularly top-down refinement and incremental development practices. © 1998 John Wiley & Sons, Ltd.     

Verification framework and algorithms for integrating information distribution systems

When two competitive companies merge into one bigger company, reusing existing technical resources in each company to form a common technology becomes a priority integration task. One of the specific problems occurring during integration is the resulting integrated scopes' requirements specifications become faulty while integrating two sets of software systems from two participating companies. The integrated scopes refer to the domains of information software systems, business policies, business processes, business rules, interface functions, and data that are being integrated in each participating company.Using a Transition-Directed Graph (TDG) representation, specified requirements involved in the integration will be represented in a form of TDG to be analyzed for faults. Five efficient algorithms are developed to identify faults in the resulting TDG formatted requirement specifications. Four correction algorithms are also developed to correct detected faults found in the TDG formatted requirements specifications.     

Vibes: A visual language for specifying behavioral requirements of algorithms

Manually verifying the behavior of software systems with respect to a set of requirements is a time-consuming and error-prone task. If the verification is automatically performed by a model checker however, time can be saved, and errors can be prevented. To be able to use a model checker, requirements need to be specified using a formal language. Although temporal logic languages are frequently used for this purpose, they are neither commonly considered to have sufficient usability, nor always naturally suited for specifying behavioral requirements of algorithms. Such requirements can be naturally specified as regular language recognizers such as deterministic finite accepters, which however suffer from poor evolvability: the necessity to re-compute the recognizer whenever the alphabet of the underlying model changes. In this paper, we present the visual language Vibes that both is naturally suited for specifying behavioral requirements of algorithms, and enables the creation of highly evolvable specifications. Based on our observations from controlled experiments with 23 professional software engineers and 21 M.Sc. computer science students, we evaluate the usability of Vibes in terms of its understandability, learnability, and operability. This evaluation suggests that Vibes is an easy-to-use language.     

Human factors in and requirements of the OSI environment

This paper examines the ISO open systems interconnection model as promulgated, from the standpoint of human factors research rather than from the traditional telecommunications perspective. It argues that the model needs refining in its top layer and that this layer should be considered as a general 'function' layer oriented towards users rather than just an applications layer. The vertical relationship between layers and the horizontal relationships within a layer are discussed with regard to the implications that a small change in user behaviour has for the technical specifications of the system and vice versa. Particular stress is placed on the need for a core 'native' language which would operate at any level to support human factors requirements. The surface features of the system that need to be optimized.for the user are defined in the context of existing human factors research. The paper concludes by specifying the human factors requirements for OSI     

Development of global specification for dynamically adaptive software

As software systems are becoming increasingly complex, they need to dynamically and continually adapt their behavior to changing conditions in the long-term running. There will be large numbers of adaptations in these systems when evolving and the adaptations may be unknowable until system operation. To specify these adaptations, this paper proposes the mode-supported Linear Temporal Logic (mLTL) that is an effective way to describe global specifications of adaptive software. The global specifications are defined for adaptive software as requirements from the perspective of global adapting process. The model checking problem of mLTL is also resolved using Linear Temporal Logic (LTL) and Labelled Transition System Analyser (LTSA). Finally, we provide a prototype implementation for modelling and analyzing adaptive programs, and experimental evaluation shows feasibility and scalability of our approach.     

基于进程代数规约生成软件体系结构模型的方法

需求规约到软件体系结构(SA)模型的转换是软件工程领域的一个研究热点,UML-RT广泛用于实时系统软件体系结构建模,然而基于自然语言规约建立的UML-RT模型往往是不精确的,存在二义性,为了解决这一问题,需要赋予UML-RT模型形式化语义.进程代数是一种用来解决并发系统通信问题的形式化方法,具有精确的语法和语义,并且便于机器自动检验与验证.TCSP是进程代数CSP的实时扩展,适合于规约实时系统带有时间约束的行为.提出一种基于进程代数规约生成SA模型的方法.首先建立了自然语言规约到SA模型的转换框架;然后使用时间通信顺序进程(TCSP)描述实时系统需求规约,通过建立TCSP到UML-RT的转换机制,从而实现进程代数规约到SA模型的转换;最后通过一个实例来验证该方法在实时软件建模过程中的有效性.实验分析表明通过该方法建立的UML-RT模型能够从整体上提高实时系统SA设计的可信性.     

Automated analysis of the SCR-style requirements specifications

The SCR(Software Cost Reduction)requirements method is an effective method for specifying software system requirements.This paper presents a formal model analyzing SCR-style requirements.The analysis model mainly applies state translation rules,semantic computing rules and attributes to define formal semantics of a tabular notation in the SCR requirements method,and may be used to analyze requirements specifications to be specified by the SCR requirements method.Using a simple example,this paper introduces how to analyze consistency and completeness of requirements specifications.     

Mining Patterns from Change Logs to Support Reuse-Driven Evolution of Software Architectures

Modern software systems are subject to a continuous evolution under frequently varying requirements and changes in systems’ operational environments. Lehman’s law of continuing change demands for long-living and continuously evolving software to prolong its productive life and economic value by accommodating changes in existing software. Reusable knowledge and practices have proven to be successful for continuous development and evolution of the software effectively and efficiently. However, challenges such as empirical acquisition and systematic application of the reusable knowledge and practices must be addressed to enable or enhance software evolution. We investigate architecture change logs — mining histories of architecture-centric software evolution — to discover change patterns that 1) support reusability of architectural changes and 2) enhance the efficiency of the architecture evolution process. We model architecture change logs as a graph and apply graph-based formalism (i.e., graph mining techniques) to discover software architecture change patterns. We have developed a prototype that enables tool-driven automation and user decision support during software evolution. We have used the ISO-IEC-9126 model to qualitatively evaluate the proposed solution. The evaluation results suggest that the proposed solution 1) enables the reusability of frequent architectural changes and 2) enhances the efficiency of architecture-centric software evolution process. The proposed solution promotes research efforts to exploit the history of architectural changes to empirically discover knowledge that can guide architecture-centric software evolution.     

The Core method for real-time requirements

The member companies of the Software Productivity Consortium develop large, mission-critical, real-time applications. For these companies, requirements are the top-priority problem in systems and software development. These requirements have driven the development of the Consortium Requirements Engineering (Core) method and its prototype CASE tools. Core is a single, coherent method for specifying real-time requirements that integrates object-oriented and forward models, integrates graphical and formal specifications, permits nonalgorithmic specifications, and provides a machine-like model. The Core requirements, component technologies, and conceptual model are discussed. Some important Core features are illustrated with an example of safety-shutdown software for a shipboard fuel-control system     

Specifying and controlling multi-channel web interfaces for enterprise applications

When building enterprise applications that need to be accessed through a variety of client devices, developers usually strive to implement most of the business logic device-independently while using a web browser to display the user interface. However, when those web-based front-ends shall be rendered on different devices, their differing I/O capabilities may require device-specific interaction patterns that still need to be specified and implemented efficiently. We present an approach for specifying the dialog flows in multi-channel web interfaces with very low redundancy and introduce a framework that controls web interfaces’ device-specific dialog flows according to those specifications, while keeping the enterprise application logic completely device-independent.     

Dynamic Meta Modeling with time: Specifying the semantics of multimedia sequence diagrams

The Unified Modeling Langugage (UML) offers different diagram types to model the behavior of software systems. In some domains like embedded real-time systems or multimedia systems, it is necessary to include specifications of time in behavioral models since the correctness of these applications depends on the fulfillment of temporal requirements in addition to functional requirements. UML thus already incorporates language features to model time and temporal constraints. Such model elements must have an equivalent in the semantic domain.We have proposed Dynamic Meta Modeling (DMM), an approach based on graph transformation, as a means for specifying operational semantics of dynamic UML diagrams. In this article, we extend this approach to also account for time by extending the semantic domain to timed graph transformation. This enables us to define the operational semantics of UML diagrams with time specifications. As an example, we provide semantics for special sequence diagrams from the domain of multimedia application modeling.     

Specimen Transport Systems- Design Issues in Creating Efficient Pneumatic Tube Transport Networks

Although Pneumatic Tube Systems (PTS), have existed for over 100 years, they increasingly provide an efficient and cost effective solution to many of the major transportation problems in health care premises. A successful installation relies upon the network design being suitable for the requirements of the user. However, specifications for PTS written by potential users during the procurement process tend to focus inappropriately on features and engineering details rather than on network layout and performance. Where performance criteria are given, the data is often too general to allow a detailed performance analysis to be carried out. A better understanding of the design issues affecting a PTS leads to better specified systems that deliver a higher level of performance and generate higher levels of user satisfaction with the equipment.     

On the generation of requirements specifications from software engineering models: A systematic literature review

System and software requirements documents play a crucial role in software engineering in that they must both communicate requirements to clients in an understandable manner and define requirements in precise detail for system developers. The benefits of both lists of textual requirements (usually written in natural language) and software engineering models (usually specified in graphical form) can be brought together by combining the two approaches in the specification of system and software requirements documents. If, moreover, textual requirements are generated from models in an automatic or closely monitored form, the effort of specifying those requirements is reduced and the completeness of the specification and the management of the requirements traceability are improved. This paper presents a systematic review of the literature related to the generation of textual requirements specifications from software engineering models.     

Empirical assessment of two approaches for specifying software product line use case scenarios

Modularity benefits, including the independent maintenance and comprehension of individual modules, have been widely advocated. However, empirical assessments to investigate those benefits have mostly focused on source code, and thus, the relevance of modularity to earlier artifacts is still not so clear (such as requirements and design models). In this paper, we use a multimethod technique, including designed experiments, to empirically evaluate the benefits of modularity in the context of two approaches for specifying product line use case scenarios: PLUSS and MSVCM. The first uses an annotative approach for specifying variability, whereas the second relies on aspect-oriented constructs for separating common and variant scenario specifications. After evaluating these approaches through the specifications of several systems, we find out that MSVCM reduces feature scattering and improves scenario cohesion. These results suggest that evolving a product line specification using MSVCM requires only localized changes. On the other hand, the results of six experiments reveal that MSVCM requires more time to derive the product line specifications and, contrasting with the modularity results, reduces the time to evolve a product line specification only when the subjects have been well trained and are used to the task of evolving product line specifications.     

A Knowledge-Based Software Engineering Environment for reusable software requirements and architectures

This paper describes a prototype Knowledge-Based Software Engineering Environment used to demonstrate the concepts of reuse of software requirements and software architectures. The prototype environment, which is application-domain independent, is used to support the development of domain models and to generate target system specifications from them. The prototype environment consists of an integrated set of commercial-off-the-shelf software tools and custom developed software tools.The concept of reuse is prevalent at several levels of the domain modeling method and prototype environment. The environment itself is domain-independent thereby supporting the specification of diverse application domain models. The domain modeling method specifies a family of systems rather than a single system; features characterize the variations in functional requirements supported by the family and individual family members are specified by the features they are to support. The knowledge-based approach to target system generation provides the rules for generating target system specifications from the domain model; target system specifications, themselves, may be stored in an object repository for subsequent retrieval and reuse.     

A logical approach to systems engineering artifacts: semantic relationships and dependencies beyond traceability—from requirements to functional and architectural views

Not only system assurance drives a need for semantically richer relationships across various artifacts, work products, and items of information than are implied in the terms “trace and traceability” as used in current standards and textbooks. This paper deals with the task of working out artifacts in software and system development, their representation, and the analysis and documentation of the relationships between their logical contents—herein referred to as tracing and traceability; this is a richer meaning of traceability than in standards like IEEE STD 830. Among others, key tasks in system development are as follows: capturing, analyzing, and documenting system-level requirements, the step to functional system specifications, the step to architectures given by the decomposition of systems into subsystems with their connections and behavioral interactions. Each of these steps produces artifacts for documenting the development, as a basis for a specification and a design rationale, for documentation, for verification, and impact analysis of change requests. Crucial questions are how to represent and formalize the content of these artifacts and how to relate their content to support, in particular, system assurance. When designing multi-functional systems, key artifacts are system-level requirements, functional specifications, and architectures in terms of their subsystem specifications. Links and traces between these artifacts are introduced to relate their contents. Traceability has the goal to relate artifacts. It is required for instance in standards for functional system safety such as the ISO 26262. An approach to specifying semantic relationships is shown, such that the activity of creating and using (navigating through) these relationships can be supported with automation.