20338082
Guaranteed Cost Control of Networked Control Systems: An LMI Approach
In this paper, networked control systems (NCS) is modeled as a discrete-time linear state-delayed system with norm-bounded uncertainty. Inspired by the so-called descriptor model transformation, a delay-dependent sufficient condition for the existence of a guaranteed cost controller for NCS is presented by a set of linear matrix inequalities (LMIs). The resulting controller can not only asymptotically stabilize the system but also guarantee an adequate level of performance. Theoretical analysis and illustrative results show that the control strategy presented in this paper is effective and feasible.
15649278
Robust Fault Isolation Filter Design for Networked Control Systems
In this paper, the effect of network-induced delay introduced into the control loop is modelled as time-varying disturbance. Based on this model, a fault isolation filter (FIF) for fault detection of networked control systems (NCSs) with multiple faults is then parameterized. Directional residual generations decoupling from the disturbance ensure the treatment of multiple faults appearing simultaneously or sequentially. The remaining degrees of freedom in the design of the filter's gain are used to satisfy an Hinfin disturbance attenuation and poles assignment constraints in the frame of Markov jump linear systems (MJLS). The sufficient existence conditions of the free parameters are formulated as a convex optimization problem over a couple of linear matrix inequalities (LMIs). An illustrative example is given to show the efficiency of the proposed method for NCS
1883250
Accelerated, high-quality refraction computations for volume graphics
We present an efficient framework for the high-quality rendering of discretely sampled surface-based objects with refractive effects. This requires an accurate estimation of the refraction coefficients, paired with efficient and accurate surface detection, space traversal, and backdrop image sampling. Our framework achieves these goals, by employing a high-quality spline-based filter in conjunction with a novel filtered octree space decomposition with pre-classified cells that is carefully matched to the filter and voxel neighborhood characteristics. Here, we benefit greatly from the non-negativity of the B-spline kernel. Finally, we describe an innovative scheme that achieves the high quality of pixel super-sampling on a flat backdrop plane without the overhead of tracing the actual rays across the refractive object.
14536606
On the security of an image encryption method
The security of digital images has attracted much attention, and many different image encryption methods have been proposed. Yen and Guo (see Proc. IEEE Workshop Signal Processing Systems, p.430-37, 1999) proposed a novel image encryption algorithm called BRIE (bit recirculation image encryption). This paper points out that BRIE is not secure enough from strict cryptographic viewpoint. It has been found that some defects exist in BRIE, and a known/chosen-plaintext attack can break BRIE with only one known/chosen plain-image. Experiments are made to verify the defects of BRIE and the feasibility of the attack.
36253673
A fuzzy goal programming approach to multi-objective optimization problem with priorities
Abstract In goal programming problem, the general equilibrium and optimization are often two conflicting factors. This paper proposes a generalized varying-domain optimization method for fuzzy goal programming (FGP) incorporating multiple priorities. According to the three possible styles of the objective function, the varying-domain optimization method and its generalization are proposed. This method can generate the results consistent with the decision-maker (DM)’s expectation, that the goal with higher priority may have higher level of satisfaction. Using this new method, it is a simple process to balance between the equilibrium and optimization, and the result is the consequence of a synthetic decision between them. In contrast to the previous method, the proposed method can make that the higher priority achieving the higher satisfactory degree. To get the global solution of the nonlinear nonconvex programming problem resulting from the original problem and the varying-domain optimization method, the co-evolutionary genetic algorithms (GAs), called GENOCOPIII, is used instead of the SQP method. In this way the DM can get the optimum of the optimization problem. We demonstrate the power of this proposed method by illustrative examples.
13799673
A Metric-Based Heuristic Framework to Detect Object-Oriented Design Flaws
One of the important activities in re-engineering process is detecting design flaws. Such design flaws prevent an efficient maintenance, and further development of a system. This research proposes a novel metric-based heuristic framework to detect and locate object-oriented design flaws from the source code. It is accomplished by evaluating design quality of an object-oriented system through quantifying deviations from good design heuristics and principles. While design flaws can occur at any level, the proposed approach assesses the design quality of internal and external structure of a system at the class level which is the most fundamental level of a system. In a nutshell, design flaws are detected and located systematically in two phases using a generic OO design knowledge-base. In the first phase, hotspots are detected by primitive classifiers via measuring metrics indicating a design feature (e.g. complexity). In the second phase, individual design flaws are detected by composite classifiers using a proper set of metrics. We have chosen JBoss application server as the case study, due to its pure OO large size structure, and its success as an open source J2EE platform among developers
1387754
A Service-Oriented Componentization Framework for Java Software Systems
In the fast growing global market for services, service-oriented computing has drastically changed the way in which we develop software systems. Providing competitive services to these markets will be critical to the success of businesses and organizations. Some competitive services have already been implemented in existing systems. In this paper, we present a novel service-oriented componentization framework that automatically supports: i) identifying critical business services embedded in an existing Java system by utilizing graph representations of the system models, ii) realizing each identified service as a self-contained component that can be deployed as a single unit, and iii) transforming the object-oriented design into a service-oriented architecture. A toolkit implementing our framework has been developed as an Eclipse rich client platform (RCP). Our initial evaluation has shown that our framework is effective in identifying services from an object-oriented design and migrating it to a service-oriented architecture