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.
26263616
Developing a Formal Design Analysis Framework
1459410
Towards the Operational Semantics of User-Centric Communication Models
The pervasiveness of complex communication services and the need for end-users to play a greater role in developing communication services have resulted in the creation of the Communication Virtual Machine (CVM) technology. The CVM technology consists of a Communication Modeling Language (CML) and the CVM. CML is a declarative modeling language that can be used to specify domain-specific communication services and the CVM is the platform used to realize the CML models.In this paper we explicitly define the operational semantics of CML to support (1) the synthesis of CML models into executable control scripts and (2) the handling of negotiation and media transfer events during communication. We specify the semantics of CML using label transition systems and describe in detail an algorithm that is essential for the interpretation of CML models. A case study is presented showing how the semantics support the rapid realization of a scenario from the healthcare domain.
14940267
Integrating Software Engineering Methods and Petri Nets for the Specification and Prototyping of Complex Information Systems
We present a Petri net based framework called G-Net for the modular design of complex information systems. The motivation of this framework is to integrate Petri net theory with a modular, objectoriented approach for the specification and prototyping of complex software systems. We use the client/server example to illustrate the G-Net specification of distributed systems, and how such a specification can be translated into a Predicate/Transition net for formal analysis. The differences between G-Net and hierarchical Petri net, as well as some limitations of the transformation technique, are then discussed.
13888320
A framework for implementing role-based access control using CORBA security service
The paper shows how role-based access control (RBAC) models could be implemented using CORBA Security service. A con guration of CORBA protection system is de ned. We provide de nitions of RBAC0 and RBAC1 implementations in the framework of CORBA Security and describe what is required from an implementation of CORBA Security service in order to support RBAC0RBAC3 models.
44861778
Formal Analysis of Real-Time Systems with SAM
The Software Architecture Model (SAM) is a general software architecture model based on a dual formalism combining Petri nets and temporal logic. This paper proposes a formal method for modeling and analyzing real-time systems with SAM. A high level Petri net and a linear time temporal logic are used as the theoretical basis for SAM. Behaviors of real-time systems are modeled by Petri nets, while their properties are specified by temporal logic. By translating Petri nets into clocked transition systems, we can apply the Stanford Temporal Prover to automating the analysis of real-time systems. A case study of interactive multimedia documents demonstrates our approach to modeling and analyzing real-time systems with SAM.
3145299
Resettable Zero Knowledge in the Bare Public-Key Model under Standard Assumption
In this paper we resolve an open problem regarding resettable zero knowledge in the bare public-key (BPK for short) model: Does there exist constant round resettable zero knowledge argument with concurrent soundness for $\mathcal{NP}$ in BPK model without assuming \emph{sub-exponential hardness}? We give a positive answer to this question by presenting such a protocol for any language in $\mathcal{NP}$ in the bare public-key model assuming only collision-resistant hash functions against \emph{polynomial-time} adversaries.
2501651
A Fast Line Segment Based Dense Stereo Algorithm Using Tree Dynamic Programming
Many traditional stereo correspondence methods emphasized on utilizing epipolar constraint and ignored the information embedded in inter-epipolar lines. Actually some researchers have already proposed several grid-based algorithms for fully utilizing information embodied in both intra- and inter-epipolar lines. Though their performances are greatly improved, they are very time-consuming. The new graph-cut and believe-propagation methods have made the grid-based algorithms more efficient, but time-consuming still remains a hard problem for many applications. Recently, a tree dynamic programming algorithm is proposed. Though the computation speed is much higher than that of grid-based methods, the performance is degraded apparently. We think that the problem stems from the pixel-based tree construction. Many edges in the original grid are forced to be cut out, and much information embedded in these edges is thus lost. In this paper, a novel line segment based stereo correspondence algorithm using tree dynamic programming (LSTDP) is presented. Each epipolar line of the reference image is segmented into segments first, and a tree is then constructed with these line segments as its vertexes. The tree dynamic programming is adopted to compute the correspondence of each line segment. By using line segments as the vertexes instead of pixels, the connection between neighboring pixels within the same region can be reserved as completely as possible. Experimental results show that our algorithm can obtain comparable performance with state-of-the-art algorithms but is much more time-efficient.
29420806
Strengthening QIM-Based Watermarking by Non-uniform Discrete Cosine Transform
Being extremely precise and at a low loss of perceptual quality, the attacks of value modification and optimized noise reduction still threaten the watermarking based on quantization index modulation (QIM). To resist them, the paper constructs a non-uniform discrete cosine transform (NDCT), and brings out an NDCT-QIM watermarking scheme, which embeds a watermark in a private NDCT domain with the parameters of NDCT as a secret key. The technique blinds the value modification by dispersing the attacking signal and changing its energy in the embedded domain. Because of the variable power spectrum of a watermark, the noise reduction becomes non-optimal. Some other advantages, including the ease of embedding, computational simplicity, etc., can also be acquired or maintained by the use of NDCT.
14201767
Stereo Correspondence with Occlusion Handling in a Symmetric Patch-Based Graph-Cuts Model
A novel patch-based correspondence model is presented in this paper. Many segment-based correspondence approaches have been proposed in recent years. Untextured pixels and boundaries of discontinuities are imposed with hard constraints by the discontinuity assumption that large disparity variation only happens at the boundaries of segments in the above approaches. Significant improvements on performance of untextured and discontinuity area have been reported. But, the performance near occlusion is not satisfactory because a segmented region in one image may be only partially visible in the other one. To solve this problem, we utilize the observation that the shared edge of a visible area and an occluded area corresponds to the discontinuity in the other image. So, the proposed model conducts color segmentation on both images first and then a segment in one image is further cut into smaller patches corresponding to the boundaries of segments in the other when it is assigned with a disparity. Different visibility of patches in one segment is allowed. The uniqueness constraint in a segment level is used to compute the occlusions. An energy minimization framework using graph-cuts is proposed to find a global optimal configuration including both disparities and occlusions. Besides, some measurements are taken to make our segment-based algorithm suffer less from violation of the discontinuity assumption. Experimental results have shown superior performance of the proposed approach, especially on occlusions, untextured areas, and near discontinuities
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.