30314810
Non-Associative Parallel Prefix Computation
Abstract Associativity of a binary operation allows many applications that are not possible with a non-associative binary operation. We propose a method to transform a binary expression into an associative one and present two related applications.
9829795
Poisson Generators on Mesh-Connected Computers with Multiple Broadcasting
205001001
The Towers of Hanoi Problem with Parallel Moves
Abstract This paper proposes a variant of the towers of Hanoi problem allowing parallel moves. An algorithm for this problem is presented and proved to be optimal.
33647867
Manipulating multiple stacks with ordered-heap
Abstract A new method for manipulating multiple stacks based on dynamic data structure is proposed in this paper. A simple data structure called ordered-heap is developed, in which nodes are preserved as a heap, and kept inorder traversal sequence remains unchanged. By employing ordered-heap to a multiple-stacks environment, it is easy and efficient to simultaneously handle several variable-size stacks in a sequential memory area. Our experiments show that not only the total number of item movements in the proposed method is much smaller than in the previous methods, but also the overhead for maintaining data structure in the proposed method is kept within a reasonable range.
10137544
Diagnosing Java Programs with Static Abstractions of Data Structures
Model-based software debugging helps users to find program errors and thus to reduce the overall costs for software development. In this paper, we extend our previous work to diagnose common data structure errors. The proposed logical program model derives from a collection of indexed object relations, which capture the underlying data structures at the abstraction level of objects. A case study suggests that the counterexample with the diagnoses can help the user to understand the nature of program errors and thus speed up error correction.
30935891
K-coverable polyhex graphs
3158206
Live updating operating systems using virtualization
Many critical IT infrastructures require non-disruptive operations. However, the operating systems thereon are far from perfect that patches and upgrades are frequently applied, in order to close vulnerabilities, add new features and enhance performance. To mitigate the loss of availability, such operating systems need to provide features such as live update through which patches and upgrades can be applied without having to stop and reboot the operating system. Unfortunately, most current live updating approaches cannot be easily applied to existing operating systems: some are tightly bound to specific design approaches (e.g. object-oriented); others can only be used under particular circumstances (e.g. quiescence states).In this paper, we propose using virtualization to provide the live update capability. The proposed approach allows a broad range of patches and upgrades to be applied at any time without the requirement of a quiescence state. Moreover, such approach shares good portability for its OS-transparency and is suitable for inclusion in general virtualization systems. We present a working prototype, LUCOS, which supports live update capability on Linux running on Xen virtual machine monitor. To demonstrate the applicability of our approach, we use real-life kernel patches from Linux kernel 2.6.10 to Linux kernel 2.6.11, and apply some of those kernel patches on the fly. Performance measurements show that our implementation incurs negligible performance overhead: a less than 1% performance degradation compared to a Xen-Linux. The time to apply a patch is also very minimal.
6760399
On fixed input distributions for noncoherent communication over high-SNR Rayleigh-fading channels
It is well known that independent and identically distributed Gaussian inputs, scaled appropriately based on the signal-to-noise ratio (SNR), achieve capacity on the additive white Gaussian noise (AWGN) channel at all values of SNR. In this correspondence, we consider the question of whether such good input distributions exist for frequency-nonselective Rayleigh-fading channels, assuming that neither the transmitter nor the receiver has a priori knowledge of the fading coefficients. In this noncoherent regime, for a Gauss-Markov model of the fading channel, we obtain explicit mutual information bounds for the Gaussian input distribution. The fact that Gaussian input generates bounded mutual information motivates the search for better choices of fixed input distributions for high-rate transmission over rapidly varying channels. Necessary and sufficient conditions are derived for characterizing such distributions for the worst case scenario of memoryless fading, using the criterion that the mutual information is unbounded as the SNR gets large. Examples of both discrete and continuous distributions that satisfy these conditions are given. A family of fixed input distributions with mutual information growth rate of O((loglogSNR)/sup 1-u/), u>0 are constructed. It is also proved that there does not exist a single fixed-input distribution that achieves the optimal mutual information growth rate of loglogSNR.
4792658
Active Page Generation via Customizing XML for Data Beans in E-Commerce Applications
In this paper, we analyze enabling technologies for typical e-business applications in terms of their multi-tier system architecture and their Model-Control-View (MCV) programming model. Based on observed limitations of the JSP (Java Server Page) technique commonly adopted for dynamic page generation (the view logic), we instead propose an alternative solution approach, namely, a generic schema mapping strategy to generate XML documents and DTDs from enterprise data beans. First, we describe in detail the XML generation process for the content composition logic. We also outline the XSL processing for the transformation logic. The separation of these two logics results in a generic solution to the bean viewing problem. In particular, it improves the bean reusability via its XML representative compared to the rigid strategy of hard-coding logics into JSP. Our proposed XML mapping solution represents a potentially valuable addition to future versions of the enterprise data beans specification. The trade-off between performance and flexibility of these alternative solutions is discussed. Lastly, we survey the state-of-art research results and emerging stardards related to this XML model mapping approach.