34091874
Incremental architectural modeling and verification of real-time concurrent systems
An incremental approach for architectural modeling and analysis of real-time concurrent systems is presented. The approach integrates existing formal methods, more specifically time Petri nets and real-time computational tree logic, and leverages their complementary strengths in a way that allows us to systematically enforce that architectural design meets the system's timing requirements, and to incrementally verify the conformance. Consequently, our approach is able to provide better assurance to system design and yet reduce the complexity of analysis. The approach is based on a Real-time Architectural Specification (RAS) model, which provides a formal basis to systematically maintain a correlation between the (timing) requirements of a system and its architectural design. Based on RAS, we further present a method to verify timing properties of a system design. This method helps conquer the complexity of analysis in two dimensions. Horizontally at each design level, incremental verification is achieved by introducing TPN reduction rules that allow us to compose analysis results on individual system components. Vertically across design levels, incremental verification is achieved by propagating higher-level constraints to lower-level designs so that we can safely plug a component design into a high-level architecture without having to re-verify the entire model. A naval command and control (C2) system is used throughout the paper to demonstrate the concept and usability of our approach.
24822225
Achieving a Better Middleware Design through Formal Modeling and Analysis
13531819
A visual approach to XML document design and transformation
This paper presents a visual approach to the representation and validation of multimedia document structures specified in XML and transformation of one structure to another. The underlying theory of our approach is a context-sensitive graph grammar formalism. The paper demonstrates the conciseness and expressiveness of the graph grammar formalism. An example XML structure is provided and its graph grammar representation, validation and transformation to a multimedia representation are presented.
2725088
Architecture-driven modeling of real-time concurrent systems with applications in FMS
Abstract Petri nets have become increasingly popular for flexible manufacturing systems (FMS) modeling and control because they accurately capture the concurrent, non-deterministic and time-dependent properties of the systems. While offering many advantages, conventional Petri net models suffer from some serious problems that limit their usability as design models for complex FMS. Central to these problems is the lack of an engineering support for incremental design, refinement, and analysis of large-scale systems. In this paper, we present an architecture-driven approach for the modeling and design of FMS that effectively addresses the problems while leveraging the strengths of Petri nets. The approach has two major aspects: The first is a Net-based and Object-based Architectural Model (NOAM) that introduces a well-founded architectural framework into the Petri nets notation and lays a foundation to support formal design. The second is a modeling method based on NOAM that uses architecture decomposition and refinement as the basis to reduce design complexity, to provide smooth transition from informal to formal design, and to support incremental refinement and analysis. A case study using NOAM for FMS modeling is provided to show the applicability of our approach.
9746543
Design an Interoperable Mobile Agent System Based on Predicate Transition Net Models
Mobile agents provide an effective and flexible style to develop advanced distributed systems. In order to promote interoperability and ensure the quality of mobile agent systems, it is necessary to formalize software architecture of mobile agent systems. In this paper, we not only define the software architecture of interoperable mobile agent systems using predicate transition nets, but also analyze the interoperability between agents. In addition, a formal model-driven design method to develop mobile agent systems is described with examples. Our method naturally integrates formal methods and practical approaches in the agent system design phase. The method can be used to develop other complex software systems as well.
10829689
A Framework for the Modeling and Prototyping of Distributed Information Systems
The major issues in designing Distributed Information Systems (DIS) include localization of control and data, inherent concurrency, intensive interactions among computation agents, history sensitivity, dynamic configuration and continuous system change and evolution. We propose a framework, called the G-Net model, for the specification, modeling and prototyping of DIS. The G-Net model not only provides a flexible notation to represent the executable specification of DIS through G-Net instantiation, but also offers a novel style of decentralized concurrent computation, allowing flexible inter-agent communication and interaction. A prototype of the G-Net framework has been implemented on workstations connected by a local network.
207130140
Guest Editors' Introduction: Special Issue on Embedded Software Engineering
Embedded systems, typically components of larger electro-mechanical systems with the purpose of controlling or helping such systems to achieve their overall goals, are playing an increasingly critical role in modern society and economy. According to David Tennenhouse, Chief Scientist of Intel and former director of DARPA ISO, 98% of all current computer applications are embedded systems. The market for embedded computer applications has shown explosive growth with tremendous applications in, for example, telecommunications, health-care, manufacturing, remote monitoring, and transportation, to name a few. An important trend is that embedded systems are becoming increasingly complex, software-intensive and distributed. For instance, it was projected that software written for cellular phones will reach from 2 to 5 million lines of code in the next few years. While this underscores the growing importance of software it also raises some concerns since methods of developing embedded software are lagging far behind hardware advances. The unique characteristics of embedded systems, such as complex control logic, severe limitations on resources (e.g. memory and power consumption), hard real-time constraints, and stringent performance and dependability requirements, are stressing the limits of mainstream architectures, languages, tools, and techniques. Much of the embedded software development today depends on intensive manual programming and costly yet error-prone testing methods for quality assurance. Further, current embedded software development techniques use monolithic designs which are not scalable, configurable, or adaptable. These problems have resulted in long product cycles, cost overruns, and poor system quality. These problems, if not addressed, will escalate, and significantly hinder the development and deployment of complex embedded systems. This special issue on embedded software engineering is aimed at stimulating research interests in this important emerging area, which merges software engineering methodologies and techniques with embedded system development techniques. After careful reviews, five papers were selected for the special issue. Collectively,
23293268
Novel Ω-protocols for NP
AbstractΩ-protocols, introduced by Garay, Mackenzie and Yang, is a variant of S-protocols with online extractor which is a useful tool to overcome the nest effect in concurrent scenario. In this work, we construct an Ω-protocol for Hamiltonian cycle problem, and therefore, it allows us to present Ω-protocol for any NP relation. For most general NP relations, our construction of Ω-protocols is much more efficient than the informal one described by Garay et al. and we believe that the method for our construction may be of independent interest.
45463269
Building Global Ecosystem for Collaborative Computing Research and Education
A knock-down tank for containing a liquid medium having a bottom panel, multiple side panels and a top panel secured together by fasteners inside the tank and insulated against heat transfer, the tank being made liquid tight by a plastic liner, and the top panel supporting a depending dip tube assembly whose tubes provide the only access to the liquid contained within the liner.
6786934
Concurrently Non-Malleable Zero Knowledge in the Authenticated Public-Key Model
We consider a type of zero-knowledge protocols that are of interest for their practical applications within networks like the Internet: efficient zero-knowledge arguments of knowledge that remain secure against concurrent man-in-the-middle attacks. As negative results in the area of concurrent non-malleable zero-knowledge imply that protocols in the standard setting (i.e., under no setup assumptions) can only be given for trivial languages, researchers have studied such protocols in models with setup assumptions, such as the common reference string (CRS) model. This model assumes that a reference string is honestly created at the beginning of all interactions and later available to all parties (an assumption that is satisfied, for instance, in the presence of a trusted party). A growing area of research in Cryptography is that of reducing the setup assumptions under which certain cryptographic protocols can be realized. In an effort to reduce the setup assumptions required for efficient zeroknowledge arguments of knowledge that remain secure against concurrent man-in-the-middle attacks, we consider a model, which we call the Authenticated Public-Key (APK) model. The APK model seems to significantly reduce the setup assumptions made by the CRS model (as no trusted party or honest execution of a centralized algorithm are required), and can be seen as a slightly stronger variation of the Bare Public-Key (BPK) model from [8, 30], and a weaker variation of the registered public-key model used in [3]. We then define and study man-in-the-middle attacks in the APK model. Our main result is a constant-round concurrent non-malleable zero-knowledge argument of knowledge for any polynomial-time relation (associated to a language in NP), under the (minimal) assumption of the existence of a one-way function family. We also show time-efficient instantiations of our protocol, in which the transformation from a 3-round honest-verifier zero-knowledge argument of knowledge to a 4-round concurrently non-malleable zero-knowledge argument of knowledge for the same relation incurs only O(1) (precisely, a small constant) additional modular exponentiations, based on known number-theoretic assumptions. Furthermore, the APK model is motivated by the consideration of some man-inthe-middle attacks in models with setup assumptions that had not been considered previously and might be of independent interest. We also note a negative result with respect to further reducing the setup assumptions of our protocol to those in the (unauthenticated) BPK model, by showing that concurrently non-malleable zero-knowledge arguments of knowledge in the BPK model are only possible for trivial languages.
280798
Instance-Dependent Verifiable Random Functions and Their Application to Simultaneous Resettability
We introduce a notion of instance-dependent verifiable random functions(InstD-VRFs for short). Informally, an InstD-VRF is, in some sense, a verifiable random function [23] with a special public key, which is generated via a (possibly)interactiveprotocol and contains an instance y? L? {0,1}*for a specific NP language L, but the security requirements on such a function are relaxed: we only require the pseudorandomnessproperty when y? Land only require the uniquenessproperty when y? L, instead of requiring both pseudorandomness and uniqueness to hold simultaneously. We show that this notion can be realized under standard assumption. 
 
Our motivation is the conjecture posed by Barak et al.[2], which states there exist resettably-sound resettable zero knowledge arguments for NP. The instance-dependent verifiable random functions is a powerful tool to tackle this problem. We first use them to obtain two interesting instance-dependent argument systems from the Barak's public-coin bounded concurrent zero knowledge argument [1], and then, we 
 
 1 Construct the first(constant round) zero knowledge arguments for NP enjoying a certainsimultaneous resettability under standard hardness assumptions in the plain model, which we call bounded-class resettable ZK arguments with weak resettable-soundness Though the malicious party (prover or verifier) in such system is limited to a kind of bounded resetting attack, We put NO restrictions on the number of the total resets made by malicious party. 
 1 show that, under standard assumptions, if there exist public-coin concurrent zero knowledge arguments for NP, there exist the resettably-sound resetable zero knowledge arguments for NP.