Formal Specification Language Research Articles

A framework for early design and prototyping of service-oriented applications with design patterns

Service-oriented computing is playing an important role in several domains. Today the biggest shift in mainstream design and programming is toward service-oriented applications. However, the service paradigm raises a bundle of problems that did not exist in traditional component-based development where abstraction, encapsulation, and modularity were the only main concerns. Due to their distributed, dynamic, and heterogeneous nature, service-oriented software applications require us to discover, document, and share new design patterns at the service- and architecture-level. Moreover, service-oriented applications are hard to design and validate, and demand for new foundational theories, modeling notations and analysis techniques.In line to such a vision, this article presents a framework, called SCA-PatternBox, to design and prototype service-oriented applications with design patterns. The framework relies on the OASIS standard Service Component Architecture (SCA) and on SCA component implementation types, such as SCA-Java, for supporting an “implementation-oriented” approach to service-oriented architecture modeling and to the definition and instantiation of design patterns. Moreover, in order to provide formally verified design patterns, SCA-PatternBox allows the formal specification and analysis of the functional behavioral aspects of a design pattern using a formal service specification language called SCA-ASM (Service Component Architecture-Abstract State Machine). As major evaluation of the framework, two case studies and lessons learned are presented. A final comparison of existing design pattern languages is also reported.

State of the practice for mesh generation and mesh processing software

We analyze the state of development practices for Mesh Generation and Mesh Processing (MGMP) software by comparing 27 MGMP projects. The analysis employs a reproducible method based on a grading template of 56 questions covering 13 software qualities. The software is ranked using the Analytic Hierarchy Process (AHP), a multicriteria decision making method appropriate for cases with a mix of qualitative and quantitative factors. The results reveal concerns regarding the maintainability, usability, reusability and performance of some MGMP software. Five recommendations are presented as feedback to the MGMP community: (i) Use an issue tracker for bug management and support requests. (ii) Document performance measures. (iii) Increase the use of libraries to promote software re-use to avoid “re-inventing the wheel.” (iv) Improve reproducibility by recording the set up details for the development and testing environments. (v) Improve confidence in correctness through requirements specification, formal specification languages, and automated testing.

Specifying and executing optimizations for generalized control flow graphs

Optimizations performed by compilers, usually expressed as rewrites on program graphs, are a core part of modern compilers. However, even production compilers have bugs, and these bugs are difficult to detect and resolve. In this paper we present Morpheus, a domain-specific language for formal specification of program transformations, and describe its executable semantics. The fundamental approach of Morpheus is to describe program transformations as rewrites on control flow graphs with temporal logic side conditions. The syntax of Morpheus allows cleaner, more comprehensible specifications of program optimizations; its executable semantics allows these specifications to act as prototypes for the optimizations themselves, so that candidate optimizations can be tested and refined before going on to include them in a compiler. We demonstrate the use of Morpheus to state, test, and refine the specification of a variety of transformations, including a simple loop peeling transformation for single-threaded code and a redundant store elimination optimization on parallel programs.

Security protocol specification and verification with AnBx

Designing distributed protocols is complex and requires actions at very different levels: from the design of an interaction flow supporting the desired application-specific guarantees to the selection of the most appropriate network-level protection mechanisms. To tame this complexity, we propose AnBx, a formal protocol specification language based on the popular Alice & Bob notation. AnBx offers channels as the main abstraction for communication, providing different authenticity and/or confidentiality guarantees for message transmission. AnBx extends existing proposals in the literature with a novel notion of forwarding channels, enforcing specific security guarantees from the message originator to the final recipient along a number of intermediate forwarding agents. We give a formal semantics of AnBx in terms of a state transition system expressed in the AVISPA Intermediate Format. We devise an ideal channel model and a possible cryptographic implementation, and we show that, under mild restrictions, the two representations coincide, thus making AnBx amenable to automated verification with different tools. We demonstrate the benefits of the declarative specification style distinctive of AnBx by revisiting the design of two existing e-payment protocols: iKP and SET.

Pemodelan dan Verifikasi Formal Protokol EE-OLSR dengan UPPAAL CORA

Information and Communication Technology systems is a most important part of society. These systems are becoming more and more complex and are massively encroaching on daily life via the Internet and all kinds of embedded systems. Communication protocols are one of the ICT systems used by Internet users. OLSR protocol is a wireless network communication protocol with proactive, and based on link-state algorithm. EE-OLSR protocol is a variant of OLSR that is able to prolong the network lifetime without losses of performance.Protocol verification process generally be done by simulation and testing. However, these processes unable to verify there are no subtle error or design flaw in protocol. Model Checking is an algorithmic method runs in fully automatic to verify a system. UPPAAL is a model checker tool to model, verify, and simulate a system in Timed Automata.UPPAAL CORA is model checker tool to verify EE-OLSR protocol modelled in Linearly Priced Timed Automata, if the protocol satisfy the energy efficient property formulated by formal specification language in Weighted Computation Tree Logic syntax. Model Checking Technique to verify the protocols results in the protocol is satisfy the energy efficient property only when the packet transmission traffic happens.

Representation of Raspberry PI Practice in Z Notation

The maker is the pioneer of open source, and the open hardware is the essential tools for the makers. As the typical representative of the open hardware, Raspberry Pi has been widely applied in open source since 2012. Z notation is a formal specification language based on the set theory and the first order predicate logic. So the Z notation can improve the reliability and robustness of the computer system using strict mathematical theory. This paper accomplishes a technical explanation of the concept of open hardware and the organization of the Raspberry pi via utilizing the Z notation. The Z notation of Raspberry pi is more precise and more systematic compared with the other informal specification. This research has great significance for the large-scale popularization of Raspberry pi and open hardware development.

Formal Modeling and Verification of Smart Traffic Environment with Design Aided by UML

Issue challan in response to rules violation, LED (Light Emitting Diode) and Bridge components of this proposed Smart Traffic Monitoring and Guidance System are presented in this paper to monitor violation of rules, update users about traffic congestion through LED and to provide central hub to communicate with sensors to update server about the traffic situation. It involves the Wireless Sensors and actors to communicate with the system. The proposed components require fewer resources in terms of sensors and actors. Further sensors identify violation of rules through issue challan. Secondly, LED component provides information to users about the traffic situations. Thirdly, Bridge component is used to provide central hub to communicate with different components in the proposed model and to update the server. The proposed components of this model are implemented by developing formal specification using VDM-SL. VDM-SL is a formal specification language used for analysis of complex systems. The developed specification is validated, verified and analyzed using VDM-SL Toolbox.

Formally specifying the RT-Component framework standard's port connection process

The Robot Technology Component standard forms the basis on which several component-based software frameworks for robotics are built, including OpenRTM-aist. In order to have confidence that the software framework will function as expected, we require confidence that this standard is a correct description of the expected functionality. In this article, we present a formal verification of one part of the RT-Component standard's functionality. We use the TLA+ formal specification language to specify and model-check the algorithm used to connect ports. Our specification and model-checking results show that, as expected for this relatively simple algorithm, it correctly connects the specified ports only and does not interfere with other ports. Additionally, this formal specification can serve as a clearer specification of the expected RT-Component-based framework functionality than the informal and UML-based descriptions given in the original standard document.

System Reliability using Simulation Models and Formal Methods

The general scope of the paper consists of improving the verification of simulation models through the integration of formal methods. We offer a formal verification approach of DEVS models based on Z notation. DEVS is a formalism that allows the description and analysis of the behavior of discrete event systems, i.e., systems whose state change depends on the occurrence of an event. A DEVS model is essentially validated by the simulation which permits of verifying whether it correctly describes the behavior of the system. However, a simulation does not cover all possible cases that means the model is validated only for the expected behaviors. For this reason, we have integrated the Z formal specification language in the DEVS formalism to detect errors before simulation which is still an important step for the validation. This integration consists of: (1) transforming a DEVS model into an equivalent Z specification and (2) verifying the consistency of the DEVS model on the resulting specification using the tools developed by the Z community. Such consistency is fulfilled by determinism and completeness. Thus, a DEVS model is subjected to an automatic formal verification before proceeding to its simulation.

Formal design of dynamic reconfiguration protocol for cloud applications

Cloud applications are complex applications composed of a set of interconnected software components running on different virtual machines, hosted on remote physical servers. Deploying and reconfiguring this kind of applications are very complicated tasks especially when one or multiple virtual machines fail when achieving these tasks. Hence, there is a need for protocols that can dynamically reconfigure and manage running distributed applications. In this article, we present a novel protocol, which aims at reconfiguring cloud applications. This protocol is able to ensure communication between virtual machines and resolve dependencies by exchanging messages, (dis)connecting, and starting/stopping components in a specific order. The interaction between machines is assured via a publish-subscribe messaging system. Each machine reconfigures itself in a decentralized way. The protocol supports virtual machine failures, and the reconfiguration always terminates successfully even in the presence of a finite number of failures. Due to the high degree of parallelism inherent to these applications, the protocol was specified using the LNT value-passing process algebra and verified using the model checking tools available in the CADP toolbox. The use of formal specification languages and tools helped to detect several bugs and to improve the protocol.

An ORCID based synchronization framework for a national CRIS ecosystem

PTCRIS (Portuguese Current Research Information System) is a program aiming at the creation and sustained development of a national integrated information ecosystem, to support research management according to the best international standards and practices.This paper reports on the experience of designing and prototyping a synchronization framework for PTCRIS based on ORCID (Open Researcher and Contributor ID). This framework embraces the "input once, re-use often" principle, and will enable a substantial reduction of the research output management burden by allowing automatic information exchange between the various national systems.The design of the framework followed best practices in rigorous software engineering, namely well-established principles in the research field of consistency management, and relied on formal analysis techniques and tools for its validation and verification.The notion of consistency between the services was formally specified and discussed with the stakeholders before the technical aspects on how to preserve said consistency were explored. Formal specification languages and automated verification tools were used to analyze the specifications and generate usage scenarios, useful for validation with the stakeholder and essential to certificate compliant services.

An ORCID based synchronization framework for a national CRIS ecosystem.

PTCRIS (Portuguese Current Research Information System) is a program aiming at the creation and sustained development of a national integrated information ecosystem, to support research management according to the best international standards and practices. This paper reports on the experience of designing and prototyping a synchronization framework for PTCRIS based on ORCID (Open Researcher and Contributor ID). This framework embraces the "input once, re-use often" principle, and will enable a substantial reduction of the research output management burden by allowing automatic information exchange between the various national systems. The design of the framework followed best practices in rigorous software engineering, namely well-established principles in the research field of consistency management, and relied on formal analysis techniques and tools for its validation and verification. The notion of consistency between the services was formally specified and discussed with the stakeholders before the technical aspects on how to preserve said consistency were explored. Formal specification languages and automated verification tools were used to analyze the specifications and generate usage scenarios, useful for validation with the stakeholder and essential to certificate compliant services.

Specifying linked data structures in JML for combining formal verification and testing

We show how to write concise and readable specifications of linked data structures that are applicable for both formal deductive verification and testing. A singly linked list and a binary search tree are provided as examples. The main characteristic of the specifications is the use of observer methods, in particular to express reachability of elements in a data structure. The specifications are written in the Java Modeling Language (JML) and do not require extensions of that language. This paper addresses a mixed audience of users and developers in the fields of formal verification, testing, and specification language design. We provide an in-depth description of the proposed specifications and analyze the implications both for verification and testing. Based on this analysis we have developed verification techniques that are implemented in the deductive verification tool KeY and enable fully automatic verification of the linked list example. This techniques are also described in this paper.

An Integration of UML Sequence Diagram with Formal Specification Methods—A Formal Solution Based on Z

UML Diagrams are considered as a main component in requirement engineering process and these become an industry standard in many organizations. UML diagrams are useful to show an interaction, behavior and structure of the system. Similarly, in requirement engineering, formal specification methods are also being used in crucial systems where precise information is required. It is necessary to integrate System Models with such formal methods to overcome the requirements errors i.e. contradiction, ambiguities, vagueness, incompleteness and mixed values of abstraction. Our objective is to integrate the Formal Specification Language (Z) with UML Sequence diagram, as sequence diagram is an interaction diagram which shows the interaction and proper sequence of components (Methods, procedures etc.) of the system. In this paper, we focus on components of UML Sequence diagram and then implement these components in formal specification language Z. And the results of this research papers are complete integrated components of Sequence diagram with Z schemas, which are verified by using tools and model based testing technique of Formal Specifications. Results can be more improved by integrating remaining components of Sequence and other UML diagrams into Formal Specification Language.

Prototype of a Decision Table Generation Tool from the Formal Specification

This research has implemented a prototype of a decision table generation tool from the specification (the formal specification) described in a formal specification language. This paper uses the formal specification description language VDM++ which is the lightweight formal methods VDM (Vienna Development Method) to write the formal specification. We applied some general specifications to the prototype, in order to evaluate its usefulness. As a result, the prototype has improved the efficiency in test design with formal methods.

Formalization of Federated Schema Architectural Style Variability

Data integration requires managing heterogeneous schema information. A federated database system integrates heterogeneous, autonomous database systems on the schema level, whereby both local applications and global applications accessing multiple component database systems are supported. Such a federated database system is a complex system of systems which requires a well-designed organization at the system and software architecture level. A specific challenge that federated database systems face is the organization of schemas into a schema architecture. This paper provides a detailed, formal investigation of variability in the family of schema architectures, which are central components in the architecture of federated database systems. It is shown how the variability of specific architectures can be compared to the reference architecture and to each other. To achieve this, we combine the semi-formal object-oriented modeling language UML with the formal object-oriented specification language Object-Z. Appropriate use of inheritance in the formal specification, as enabled by Object-Z, greatly supports specifying and analyzing the variability among the studied schema architectures. The investigation also serves to illustrate the employed specification techniques for analyzing and comparing software architecture specifications.

Formalizing Mobile Ad Hoc and Sensor Networks Using VDM-SL

Mobile ad hoc and sensor networks (MAHSNs) are expected to become the fabric of modern societies. Despite considerable advancements, these networks are yet unable to surmount many operational challenges especially in safety-critical large-scale applications. Most of the published research focused on performance analysis of nonfunctional properties and ignore correctness of the approach which is vital in large and complex systems. This paper investigates an alternative formal specification and analysis technique for MAHSNs. We model MAHSNs as dynamic graph and employ VDM-SL for formal specification and verification of LASCNN algorithm. Constraints are put on the data where required to support validation of the formal algorithm. Pre and post conditions are defined for correct operation of communication in terms of messages. VDM-SL is used because it is a formal specification language to describe detailed examination of the system. The specification is analyzed and validated using VDM-SL toolbox.

Using Formal Methods for Test Case Generation According to Transition-Based Coverage Criteria

- Formal methods play an important role in increasing the quality, reliability, robustness and effectiveness of software. Also the uses of formal methods, especially in safety-critical systems, help in the early detection of software errors and failures which will reduce the cost and effort involved in software testing. The aim of this paper is to prove the role and the effectiveness of formal specification for the cruise control system (CCS) as a case study. A CCS formal model is built using Perfect formal specification language, and its correctness is validated using the Perfect Developer toolset. We develop a software testing tool in order to generate test cases using three different algorithms. These test cases are evaluated to improve their coverage and effectiveness. The results show that random test case generation with full restriction algorithm is the best in its coverage results; the average of the path coverage is 77.78% and the average of the state coverage is 100%. Finally, our experimental results show that Perfect formal specification language is appropriate to specify CCS which is one of the most safety-critical software systems, so the process of detecting all future possible cases becomes easier.

Automated Analysis of Internet Key Exchange Protocol v2 for Denial of Service Attacks

The Denial of service (DoS) and Distributed Denial of Service (DDoS) attacks are aimed at maliciously consuming the available resources in computing systems to prevent genuine users from legitimately accessing them. These attacks can easily interrupt or disable targeted systems, so it is important for the system to detect and filter bogus connection requests as early as possible. Many common protocols TCP, HIP, SSL, etc., are vulnerable to DoS attacks. Until now, there has been no fit for all, generic solution to resist a DoS/DDoS attacks presented. An attractive alternative therefore is to investigate the approaches by which one can at least reduce the impact of the DoS/DDoS attacks. Our research work presented here focuses on the same. We develop a formal model of Internet Key Exchange version 2 (IKEv2) protocol using formal specification language of Colored Petri Nets (CPNs) to analyze the protocol for DoS attacks. IKEv2 is a member of the IPSec protocol suite and establishes a security association that includes secret information between source and destination. IPSec provides security services to applications viz. VPN, remote login, email, file transfer etc. Till date no automatic formal analysis of IKEv2 protocol is attempted for DoS attacks, hence we choose IKEv2 protocol to illustrate automatic analysis for DoS attacks. We use simulation approach of CPNs to analyze the protocol for DoS attacks. We analyze the processing cost and memory cost to carry out DoS attacks in IKEv2. In addition, we measure the strength of the protocol against DoS attacks using different experiments in CPNs.

Human organizational patterns applied to collaborative learning software systems

Within socially driven software development methodologies like Tropos, a new software system could be modeled as a set of collaborating actors pursuing collective and individual goals. These actors could possibly be structured around an organizational pattern. The organizational model could then, within the design of the system, be mapped to the software behavior through the use of logical agents. This paper overviews a set of human organizational styles from organization theory literature and applied here in an original manner to the representation of collaborative learning software systems. The structure-in-5 is indeed applied to a Learning Management System development and the joint venture to a Massive Open Online Course one. Being by nature a network of social interactions, collaborative learning systems are perfectly adequate for agent-oriented software development. Besides, the two above-mentioned organization styles are further represented using the i* modeling language and a formal specification language. A set of non-functional requirements is also identified and these organizational styles are further evaluated in the light of these.