A Survey of Languages for Specifying Dynamics: A Knowledge Engineering Perspective

A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machine

A methodology for the evaluation of program cost and schedule risk for the SEASAT program

An interactive computerized project management software package (RISKNET) is designed to analyze the effect of the risk involved in each specific activity on the results of the total SEASAT-A program. Both the time and the cost of each distinct activity can be modeled with an uncertainty interval so as to provide the project manager with not only the expected time and cost for the completion of the total program, but also with the expected range of costs corresponding to any desired level of significance. The nature of the SEASAT-A program is described. The capabilities of RISKNET and the implementation plan of a RISKNET analysis for the development of SEASAT-A are presented

An Overview of the MPEG-7 Description Definition Language (DDL) Proposals

This paper describes the DDL proposals submitted in response to the MPEG-7 Call for Proposals and the results of their evaluation at the MPEG-7 AHG Test and Evaluation Meeting in Lancaster in February 1999. It also describes the proposal from DSTC which was considered to provide the best starting point for a DDL and the features from other proposals which were considered to be of value for future consideration and possible integration. It concludes with an overview of the current state of the MPEG-7 DDL work

An "Improved" Proposal for an MPEG-7 DDL

This documents outlines a modified version of MPEG-7 DDL proposal P547, which was presented at the Lancaster MPEG-7 Test and Evaluation Meeting. It represents a first attempt to incorporate the changes which were suggested by the DDL Evaluation Team in Lancaster and also attempts to improve certain aspects which were determined to be incomplete

A Proposal for an MPEG-7 Description Definition Language

This paper proposes a schema for MPEG-7, a "Multimedia Content Description Interface". A schema is proposed which is capable of meeting the requirements of the DDL as described in the MPEG-7 Requirements Document. This schema is capable of defining the envisaged description schemes as well as validating and constraining audiovisual document descriptions and their associated data models

Protecting Systems From Exploits Using Language-Theoretic Security

Any computer program processing input from the user or network must validate the input. Input-handling vulnerabilities occur in programs when the software component responsible for filtering malicious input---the parser---does not perform validation adequately. Consequently, parsers are among the most targeted components since they defend the rest of the program from malicious input. This thesis adopts the Language-Theoretic Security (LangSec) principle to understand what tools and research are needed to prevent exploits that target parsers. LangSec proposes specifying the syntactic structure of the input format as a formal grammar. We then build a recognizer for this formal grammar to validate any input before the rest of the program acts on it. To ensure that these recognizers represent the data format, programmers often rely on parser generators or parser combinators tools to build the parsers. This thesis propels several sub-fields in LangSec by proposing new techniques to find bugs in implementations, novel categorizations of vulnerabilities, and new parsing algorithms and tools to handle practical data formats. To this end, this thesis comprises five parts that tackle various tenets of LangSec. First, I categorize various input-handling vulnerabilities and exploits using two frameworks. First, I use the mismorphisms framework to reason about vulnerabilities. This framework helps us reason about the root causes leading to various vulnerabilities. Next, we built a categorization framework using various LangSec anti-patterns, such as parser differentials and insufficient input validation. Finally, we built a catalog of more than 30 popular vulnerabilities to demonstrate the categorization frameworks. Second, I built parsers for various Internet of Things and power grid network protocols and the iccMAX file format using parser combinator libraries. The parsers I built for power grid protocols were deployed and tested on power grid substation networks as an intrusion detection tool. The parser I built for the iccMAX file format led to several corrections and modifications to the iccMAX specifications and reference implementations. Third, I present SPARTA, a novel tool I built that generates Rust code that type checks Portable Data Format (PDF) files. The type checker I helped build strictly enforces the constraints in the PDF specification to find deviations. Our checker has contributed to at least four significant clarifications and corrections to the PDF 2.0 specification and various open-source PDF tools. In addition to our checker, we also built a practical tool, PDFFixer, to dynamically patch type errors in PDF files. Fourth, I present ParseSmith, a tool to build verified parsers for real-world data formats. Most parsing tools available for data formats are insufficient to handle practical formats or have not been verified for their correctness. I built a verified parsing tool in Dafny that builds on ideas from attribute grammars, data-dependent grammars, and parsing expression grammars to tackle various constructs commonly seen in network formats. I prove that our parsers run in linear time and always terminate for well-formed grammars. Finally, I provide the earliest systematic comparison of various data description languages (DDLs) and their parser generation tools. DDLs are used to describe and parse commonly used data formats, such as image formats. Next, I conducted an expert elicitation qualitative study to derive various metrics that I use to compare the DDLs. I also systematically compare these DDLs based on sample data descriptions available with the DDLs---checking for correctness and resilience

Validation of bitstream syntax and synthesis of parsers in the MPEG Reconfigurable Video Coding framework

International audienceVideo coding technology has evolved in the past years into a variety of different and complex algorithms. So far the specification of such standard algorithms has been done case by case providing monolithic textual and reference SW specifications, but without any attention on commonalities and the possibility of incremental improvements or modifications of such monolithic standards. The MPEG Reconfigurable Video Coding (RVC) framework is a new ISO standard, currently under development aiming at providing video codec specifications at the level of library functions instead of monolithic algorithms. The possibility to select a subset of standard coding algorithms to specify a decoder that satisfies application specific constraints is very attractive. However, such possibility to reconfigure codecs requires systematic procedures and tools capable of describing the new bitstream syntaxes of such new codecs. Moreover, it is also necessary to generate the associated parsers which are capable to parse the new bitstreams because they are not available "a priori" in the RVC library. This paper further explains the problem and describes the technologies used to describe new bitstream syntaxes within RVC. In addition, the paper describes the methodology and the tools for the validation of bitstream syntaxes descriptions as well as an example of systematic procedures for the direct synthesis of parsers in the same data flow formalism in which the RVC library component are implemented

Towards a syntax for multimedia semantics

This article describes the current state of the art on representing the fouressential conceptual facets of a multimedia unit, namely the form and substance of content and the form and substance of its expression, and points to the still un solved problems regarding the syntax for media semantics. We first provide a brief overview of the general features of the MPEG-7 standard and its different parts. This serves as a description of the state of the art in content description for audio-visual media. We then analyse the ability of one of these parts for its capability to define structures for describing media semantics. We describe the problems of two currently conflicting MPEG-7 representations of expression-based media semantic, which should be equivalent. We then discuss high-level aspects of media semantics, namely the general problems of an ontology for media semantics. Finally, we talk about the problems of applying the theoretical conceptsto real applications