The discrete algebraic reconstruction technique has many advantages in computed tomography and electron tomography. However, the number of gray levels and the absolute gray values that should be known in advance are typically not available in experiments especially when there are many gray levels in the image. In this paper, we report an automatic discrete tomography reconstruction algorithm to improve its feasibility in practice, without needing to know these two parameters. In our algorithm, the number of gray levels is estimated by labeling the connected components in the tomogram and the absolute values of them are determined by the modal value of each domain. The proposed algorithm was extensively validated on both simulated and experimental datasets. The results show that our algorithm can accurately recover not only the morphology but also the gray levels of the interested objects, even in the images with multiple gray levels. It is demonstrated that the presented algorithm is robust for eliminating missing wedge artifacts and tolerable for noisy data.

Commercial-off-the-shelf (COTS) components are increasingly used in building high-confidence systems to assure their dependability in an affordable way. The effectiveness of such a COTS-based design critically depends on the design of the COTS components. Their dependability attributes need a thorough understanding and rigorous assessment yet has received relatively little attention. The research presented in this paper investigates the error detection and recovery features of contemporary high-performance COTS microprocessors. A method of assessment is proposed and two state-of-the-art microprocessors are studied and compared.

Describes OFTT (OLE Fault Tolerance Technology), a fault tolerance middleware toolkit running on the Microsoft Windows NT operating system that provides the required fault tolerance for networked PCs in the context of industrial process monitoring and control applications. It is based on the Microsoft Component Object Model (COM) and consists of components that perform checkpoint-saving, failure detection, recovery and other fault tolerance functions. The ease with which this technology can be incorporated into an application represents the primary innovation. It is hoped that, by making fault tolerance more compatible with standard software architectures, more reliable PC-based monitoring and control systems can be built conveniently.