Formal Methods Approach Research Articles

Parsing of Research Documents into XML Using Formal Grammars

Automatic information extraction of content and style format in paged documents is challenging. It requires the conversion of the original document into a granular level of details for which every document section and content is identifiable. This functionality or tool does not exist for any academic research document yet. In this paper, we present an automated process of parsing research paper documents into XML files using a formal method approach of context-free grammars (CFGs) and regular expressions (REGEXs) definable of a standard template. We created a tool for the algorithms to parse these documents into tree-like structures organized as XML files named research_XML (RX) parser. The RX tool performed the extraction of syntactic structure and semantic information of the document’s contents into XML files. These XML output files are lightweight, analyzable, query-able, and web interoperable. The RX tool has a success rate of 91% when evaluated on fifty varying research documents of 160 average pages and 8,004 total pages. The tool and test data are accessible on GitHub repo. The novelty of our process is specific to applying formal techniques for information extraction in structured multipaged documents and academic research documents thus advancing the research in automatic information extraction.

A State Space Approach to Decentralized Fault SE-Coprognosability of Partially Observed Discrete Event Systems.

The problem of fault prognosis in the context of discrete event systems (DESs) is a crucial subject to study the security and maintenance of cyber-physical systems. In this article, the decentralized fault prognosis of partially observed DESs is analyzed with a universal state-estimate-based protocol. It follows (M,K) as the performance bound of any expected decentralized prognosers, where any fault can be predicted K steps before its occurrence and the fault is guaranteed to occur within M steps once a corresponding fault alarm is issued. To determine whether expected decentralized prognosers exist, the notion of state-estimate-coprognosability (SE-coprognosability) under the case of one fault type is proposed. Compared with existing other kinds of coprognosability, SE-coprognosability is a more generalized concept. Meanwhile, combining the formal method and algebraic state space approach, a novel state estimation algorithm is presented and based on which, the verification of SE-coprognosability is also solved.

Comparative legal study defining the bill of lading significance in maritime transport of goods

The given research paper studies the regulatory normative acts of the Russian Federation and foreign states related to the legal meaning of the bill of lading applying the following scientific methods: dialectical method, the comparative legal and historical ones, systematic, formal legal method and special legal interpretation approach. Particular attention is paid to the legal documents of the United States of America and Great Britain as the legal acts of these countries have had the greatest impact on all foreign legislation related to the carriage of goods by sea in general, and the bill of lading, in particular. The authors highlight the points that require a more detailed study as well as other general and different features of the bill of lading in the Russian Federation and in other foreign states legislation. The problematic aspects of the bill of lading caused by the peculiarities of the Russian Federation historical development are also determined in the article. The studied material allows the authors to propose certain amendments to the current legislation of the Russian Federation: to include the legal regulations of the bill of lading into the legislative codified act – the Code of Merchant Shipping of the Russian Federation while at present they are mainly located in by-laws.

AHAPII SHAMRAI IN SEARCH OF SYNTHETIC THEORY OF LITERATURE: 1920s

This article reconstructs the theoretical views of a literary historian and critic Ahapii Pylypovych Shamrai (1896—1952) in the context of perception of Oleksandr Potebnia’s philological and linguistic heritage — and at the same time in the context of the development of the formal method and sociological approach in Ukrainian literary criticism in the 1920s. The study offers a detailed analysis of Shamrai’s early work “O. Potebnia and the methodology
 of the history of literature” (1924) in the connection with Russian formalists’ critical approach to Potebnia’s theoretical ideas. In his early work, Shamrai calls for a rethinking of Potebnia’s theory of the ‘inner form of the word’ and some of his other ideas, which, in his opinion, could be the basement for the further development of Ukrainian and Russian literary theory. Particular attention is paid to the study of a reader (audience) as a major component of literary analysis and interpretation. The idea of ‘studying a reader’ was crucial when Ukrainian scholars tried to combine two theoretical approaches — the formal and sociological methods. One of the best examples of such ‘synthetism’ in Ukrainian literary studies of the 1920s was Shamrai’s textbook “Ukrainian Literature. Brief overview” (1927, 1928), which is discussed in this article. The paper also argues that “synthetism” was inherent to the Ukrainian literary criticism of the 1920s in general. It was a theoretical framework used by many Ukrainian literary scholars, Oleksandr Biletskyi and Borys Jakubskyi being among them. Providing a historical context for Shamrai’s theories, the article also examines the historical and philological ideas of his older contemporary Oleksandr Biletskyi and estimates their influence on the development of Ukrainian literary criticism of that time

Three kinds of coprognosability for partially-observed discrete event systems via a matrix approach

Due to the important application in security and safety analysis, fault prognosis of discrete event systems (DESs) plays a more vital role in study of Cyber–physical systems. In this work, we study the problem of decentralized fault prognosis in the context of partially-observed DESs. Different from existing results, we establish algebraic structures of given systems under decentralized agents by semi-tensor product rather than observers or verifiers based on formal language methods. The structure matrices of decentralized partially-observed DESs are polynomial in the size of a given system and linear about the number of agents. Besides, combining the formal method and algebraic state space approach, we discuss three kinds of coprognosability, called (M,K)-disjunctive-coprognosability aiming at disjunctive architectures, (M,K)-conjunctive-coprognosability for conjunctive architectures and (M,K)-strongly-coprognosability focusing on general structures, respectively. Here, (M,K) is the performance bound of a given prognostic system. In order to take both fault prediction and isolation into consideration, the decentralized prognoser is required to issue the “j” alarm for the jth type of fault and “0” means no fault alarm. Meanwhile, we propose a polynomial-time algorithm to verify each kind of coprognosability based on the structure matrix approach and show that each verification is not separate.

A formal methods approach to interpretable reinforcement learning for robotic planning.

Growing interest in reinforcement learning approaches to robotic planning and control raises concerns of predictability and safety of robot behaviors realized solely through learned control policies. In addition, formally defining reward functions for complex tasks is challenging, and faulty rewards are prone to exploitation by the learning agent. Here, we propose a formal methods approach to reinforcement learning that (i) provides a formal specification language that integrates high-level, rich, task specifications with a priori, domain-specific knowledge; (ii) makes the reward generation process easily interpretable; (iii) guides the policy generation process according to the specification; and (iv) guarantees the satisfaction of the (critical) safety component of the specification. The main ingredients of our computational framework are a predicate temporal logic specifically tailored for robotic tasks and an automaton-guided, safe reinforcement learning algorithm based on control barrier functions. Although the proposed framework is quite general, we motivate it and illustrate it experimentally for a robotic cooking task, in which two manipulators worked together to make hot dogs.

A formal methods approach to predicting new features of the eukaryotic vesicle traffic system

Vesicle traffic systems (VTSs) transport cargo among the intracellular compartments of eukaryotic cells. The compartments are viewed as nodes that are labeled by their chemical identity and the transport vesicles are similarly viewed as labeled edges between the nodes. Several interesting questions about VTSs translate to combinatorial search and synthesis problems. We present novel encodings for the problems based on Boolean satisfiability (SAT), satisfiability modulo theories and quantified Boolean formula of the properties over vesicle traffic systems. We have implemented the presented encodings in a tool that searches for the networks that satisfy properties related to transport consistency conditions using these solvers. In our numerical experiments, we show that our tool can search for networks of sizes that are relevant to real cellular systems. Our work illustrates the potential of novel biological applications of SAT solving technology.

A Secure Protocol for Remote-Code Integrity Attestation of Embedded Systems: The CSP Approach

No doubt, a person of modern society relying on Embedded Systems (ESs) has increased rapidly and the era of digital machines is gaining popularity among users and also systems providers. At the same time, such instruments face substantial security challenges because they usually operate in a physically unprotected environment, and thus attract the attackers to gain unauthorized access for utilizing the system functions. Accordingly, system integrity is important and hence there is a need to propose a technique/tool to verify that the original/pure systems codes have been used in those devices. In this research, our main objective is to design a system architecture with a secure communication for code integrity attestation of an ES. Indeed, the study presents the proposed system architecture for ESs integrity attestation which includes two main phases: fetching an ES code at a server site and examining the ES at a remote site (using a designed user application). Essentially, the hash function (SHA-2) with a random key to calculate a unique digest value for a targeted system have been utilized. Also, the study used timestamps and nonce values, two secure keys, and public key algorithm to design a secure protocol in-order to prevent potential attacks during data and the associated values transfer between the server and the remote user application. As many researchers state that the formal methods are very precise and accurate for presenting system specifications; this study modeled and analyzed the proposed attestation protocol using the Communicating Sequential Processes (CSP) formal method approach. Besides, the Compiler for the Analysis of Security Protocols (Casper) has been used to translate the protocol description into the corresponding process algebra CSP model. Then, the researcher used the Failures Divergences Refinement (FDR) to evaluate the proposed protocol. Those formal method tools are considered as a reliable verification measurement in-order to figure-out potential flaws and correct them. Overall, the final output of checking all the defined secrecy and authentication assertions using FDR 4.2.0, and thus all the secrecy and authentication specifications defined in the developed Casper script are passed.

A Formal Methods Approach for Predicting How Users will Utilize System Features

Model checking is increasingly being used with task analytic behavior models to prove whether models of human-interactive systems are safe and reliable. Such methods could be used to predict how different types of users will choose to use system features. However, existing methods focus on modeling the full space of possible human behaviors without considering how users will choose to navigate this space. In this work, we present a new approach that enables model checking to predict how different types of users will use features of an interactive system by employing a novel combination of task analytic modeling and utility theory. This paper presents this method and illustrates its power with a smart thermostat application. The results of the application analysis and its implications for future research are discussed.

Formal Verification of Medical CPS

The use of robots in operating rooms improves safety and decreases patient recovery time and surgeon fatigue, but it introduces new potential hazards that can lead to severe injury or even the loss of human life. Thus, safety has been perceived as a crucial system property since the early days by the industry, the medical community, and the regulatory agents. In this article, we discuss the application of the mathematically rigorous technique known as Formal Verification to analyze the safety properties of a laser incision case study, and we assess its safe and predictable operation. Like all formal methods approaches, our analysis has three distinct components: a method to create a model of the system, a language to specify the properties, and a strategy to prove rigorously that the behavior of the model fulfills the desired properties. The model of the system takes the form of a hybrid automaton consisting of a discrete control part that operates in a continuous environment. The safety constraints are formalized as reachability properties of the hybrid automaton model, while the verification strategy exploits the capabilities of the tool A riadne to address the verification problem and answer the related questions ranging from safety to efficiency and effectiveness.

A Formal Methods Approach to Pattern Recognition and Synthesis in Reaction Diffusion Networks

We introduce a formal framework for specifying, detecting, and generating spatial patterns in reaction diffusion networks. Our approach is based on a novel spatial superposition logic, whose semantics is defined over the quad-tree representation of a partitioned image. We demonstrate how to use rule-based classifiers to efficiently learn spatial superposition logic formulas for several types of patterns from positive and negative examples. We implement pattern detection as a model-checking algorithm and we show that it achieves very good results on test data sets which are different from the training sets. We provide a quantitative semantics for our logic and we develop computational framework where our quantitative model-checking algorithm works in synergy with a particle swarm optimization technique to synthesize the parameters leading to the formation of desired patterns in reaction diffusion networks.

A formal methods approach to semiotic engineering

Abstract This work introduces a formal methods approach to semiotic engineering: Browser-Integrated Guidance for Specifying Interface Signifiers (BIGSIS). Drawing from the semiotic engineering and formal methods literature, BIGSIS facilitates logical reasoning about human-system interface signifiers with respect to measures of effective and efficient designer-to-user communication. Signifiers that communicate correct functions or meanings are effective, and signifiers that convey nonconflicting functions or meanings are efficient. The BIGSIS approach incorporates a five-step process, an XML syntax, a Z notation formalism, an XML-to-Symbolic-Analysis-Laboratory (SAL) translator, and three signifier specifications: internal consistency, inter-channel consistency, and completeness. These elements of the approach support two analyses: BIGSIS-XML and model checking. The BIGSIS-XML analysis addresses one interface component, one sensory channel (visual, audio, or haptic), and one target-system configuration at a time. Using SAL, the model checking analysis considers all interface components including documentation, sensory channels, and a broad range of target-system configurations. We demonstrate an application of BIGSIS with a medical device case study. The analysis considers four components on the system’s controller, three sensory channels, and signified information from U.S. cultural context and explanations within an accompanying patient handbook. The BIGSIS-XML analysis aids in identifying 12 potential designer-to-user communication problems: ten involving effectiveness and two involving efficiency. The model checking analysis aids in identifying six potential designer-to-user communication problems: four involving effectiveness and two involving efficiency. Case study results indicate that BIGSIS shows promise for identifying potential instances of ineffective and inefficient designer-to-user communication in the design of a complex, safety-critical system interface.

Design of decentralized critical observers for networks of finite state machines: A formal method approach

Motivated by safety-critical applications in cyber–physical systems, in this paper we study the notion of critical observability and design of observers for networks of Finite State Machines (FSMs). Critical observability corresponds to the possibility of detecting if the current state of an FSM is in a given region of interest, called set of critical states. A critical observer detects on-line the occurrence of critical states. When a large-scale network of FSMs is considered, the construction of such an observer is prohibitive because of the large computational effort needed. We propose a decentralized architecture for critical observers of networks of FSMs, where on-line detection of critical states is performed by local critical observers, each associated with an FSM of the network, which do not need to interact. For the efficient design of decentralized critical observers we first extend on-the-fly algorithms traditionally used in the community of formal methods for the verification and control design of FSMs. We then extend to networks of FSMs, bisimulation theory traditionally given in the community of formal methods for single FSMs. The proposed techniques provide a remarkable computational complexity reduction, as discussed throughout the paper and also demonstrated by means of illustrative examples.

A Workflow-Driven Formal Methods Approach to the Generation of Structured Checklists for Intrahospital Patient Transfers.

Intrahospital transfers are a common but hazardous aspect of hospital care, with a large number of incidents posing a threat to patient safety. A growing body of work advocates the use of checklists for minimizing intrahospital transfer risk, but the majority of existing checklists are not guaranteed to be error-free and are difficult to adapt to different clinical settings or changing hospital policies. This paper details an approach that addresses these challenges through the employment of workflow technologies and formal methods for generating structured checklists. A three-phased methodology is proposed, where intrahospital transfer processes are first conceptualized, then rigorously composed into workflows that are mechanically verified, and finally, translated into a set of checklists that support hospital staff while maintaining the dependencies between different transfer tasks. A case study is presented, highlighting the feasibility of this approach, and the correctness and maintainability benefits brought by the logical underpinning of this methodology. A checklist evaluation is discussed, with promising results regarding their usefulness.

Code generation for Event-B

Event-B is a modelling language and a formal methods approach for correct construction of software. This paper presents our work on code generation for Event-B, including the definition of a syntactic translation from Event-B to JML-annotated Java programs, the implementation of the translation as the EventB2Java tool, and two case studies on the use of EventB2Java. The first case study is on implementing an Android application with the aid of the EventB2Java tool, and the second on testing an Event-B specification of the Tokeneer security-critical system. Additionally, we have benchmarked our EventB2Java tool against two other Java code generators for Event-B.

Frontier technologies of trust computing and network security

The increasing complexity of computer systems and communication networks induces tremendous requirements for trust and security. This special issue includes topics on trusted computing, risk and reputation management, network security and survivable computer systems/networks. These issues have evolved into an active and important area of research and development. The past decade has witnessed a proliferation of concurrency and computation systems for practice of highly trust, security and privacy, which has become a key subject in determining future research and development activities in many academic and industrial branches. This special issue aims to present and discuss advances of current research and development in all aspects of trusted computing and network security. In addition, this special issue provides snapshots of contemporary academia work in the field of network trusted computing. We prepared and organized this special issue to record state-of-the-art research, novel development and trends for future insight in this domain. In this special issue, 14 papers have been accepted for publication, which demonstrate novel and original work in this field. A detailed overview of the selected works is given below.

Distributed Multi-Agent Persistent Surveillance Under Temporal Logic Constraints

We consider the problem of finding optimal agent trajectories for persistent surveillance missions subject to temporal logic (TL) constraints. Specifically, we aim to minimize the time between two consecutive visits to regions of interest in a partitioned environment while satisfying each agent's TL specification. We formulate a distributed optimization problem, where each agent plans its trajectory based only on local information. We use a formal methods approach to show that any trajectory resulting from the proposed controller satisfies the corresponding TL constraints. The results are illustrated through simulations by comparing the proposed strategy with a joint planner and a planner without communication.

A linear logic approach to the composition of RESTful web services

RESTful web services, which are declarative, lightweight and easy to access, are already widely used for exposing services on the internet and have attracted increasing interest from industry. The rising number of services being implemented and made available on the web is creating a demand for modelling techniques that can abstract REST design from the implementation in order to better specify, analyse and implement large-scale RESTful web systems. It can also help by providing suitable RESTful web service composition methods which can reduce costs by efficiently re-using the large number of services that are already available and by exploiting existing services for complex business purposes. This paper introduces a formal model of RESTful web services in linear logic and proposes a formal method approach for RESTful web service composition based on planning using linear logic via theorem proving. This is a two-stage planning method that finds resources for the composition at both the abstract resource and the service operation levels. It greatly improves the searching efficiency and guarantees the correctness and completeness of the service composition process. The paper demonstrates a further validation of the planning method through its implementation in the interactive Coq logic proof assistant.

An integrated authentication and authorization approach for the network of information architecture

Several projects propose an information centric approach to the network of the future. Such an approach makes efficient content distribution possible by making information retrieval host-independent and integration into the network storage for caching information. Requests for particular content can, thus, be satisfied by any host or server holding a copy. One well-established approach of information centric networks is the Network of Information (NetInf) architecture, developed as part of the EU FP7 project SAIL. The approach is based on the Publish/Subscribe model, where hosts can join a network, publish data, and subscribe to publications. The NetInf introduces two main stages namely, the Publication and Data Retrieval through which hosts publish and retrieve data. Also, a distributed Name Resolution System (NRS) has been introduced to map the data to its publishers. The NRS is vulnerable to masquerading and content poisoning attacks through invalid data registration. Therefore, the paper proposes a Registration stage to take place before the publication and data retrieval stage. This new stage will identify and authenticate hosts before being able to access the NetInf system. Furthermore, the Registration stage uses (cap)abilities-based access policy to mitigate the issue of unauthorized access to data objects. The proposed solutions have been formally verified using formal methods approach.

Modelling High Integrity Transport Systems by Formal Methods

This paper discusses and promotes the application of formal method approach in the development of high integrity transport systems. It briefly addresses the problems of the design and implementation of safety-critical, real-time control systems in transport systems. With the introduction of the concepts of the formal methods, the software development process is explained and the advantages of simple translation and eliminations of hidden defects are highlighted. A simple example on railway signalling is then given to demonstrate the application of formal methods in high integrity transport system.