The movingA-B interface emits second sound which extracts the latent heat from the transition region. The amplitude is calculated for all interface velocities
. A pronounced maximum is found if
is close to the second sound velocity. 相似文献
In this paper, we introduce a fast and consistent smoothed particle hydrodynamics (SPH) technique which is suitable for convection–diffusion simulations of incompressible fluids. We apply our temporal blending technique to reduce the number of particles in the simulation while smoothly changing quantity fields. Our approach greatly reduces the error introduced in the pressure term when changing particle configurations. Compared to other methods, this enables larger integration time‐steps in the transition phase. Our implementation is fully GPU‐based to take advantage of the parallel nature of particle simulations.相似文献
Tutte proved that every 3-vertex-connected graph G on more than 4 vertices has a contractible edge. Barnette and Grünbaum proved the existence of a removable edge in the same setting. We show that the sequence of contractions and the sequence of removals from G to K4 can be computed in O(|V|2) time by extending Barnette’s and Grünbaum’s theorem. As an application, we derive a certificate for the 3-vertex-connectivity of graphs that can be easily computed and verified. 相似文献
Model synchronization, i.e., the task of restoring consistency between two interrelated models after a model change, is a challenging task. Triple graph grammars (TGGs) specify model consistency by means of rules that describe how to create consistent pairs of models. These rules can be used to automatically derive further rules, which describe how to propagate changes from one model to the other or how to change one model in such a way that propagation is guaranteed to be possible. Restricting model synchronization to these derived rules, however, may lead to unnecessary deletion and recreation of model elements during change propagation. This is inefficient and may cause unnecessary information loss, i.e., when deleted elements contain information that is not represented in the second model, this information cannot be recovered easily. Short-cut rules have recently been developed to avoid unnecessary information loss by reusing existing model elements. In this paper, we show how to automatically derive (short-cut) repair rules from short-cut rules to propagate changes such that information loss is avoided and model synchronization is accelerated. The key ingredients of our rule-based model synchronization process are these repair rules and an incremental pattern matcher informing about suitable applications of them. We prove the termination and the correctness of this synchronization process and discuss its completeness. As a proof of concept, we have implemented this synchronization process in eMoflon, a state-of-the-art model transformation tool with inherent support of bidirectionality. Our evaluation shows that repair processes based on (short-cut) repair rules have considerably decreased information loss and improved performance compared to former model synchronization processes based on TGGs.
Existing information-visualization techniques that target small screens are usually limited to exploring a few hundred items. In this article we present a scatterplot tool for Personal Digital Assistants that allows the handling of many thousands of items. The application's scalability is achieved by incorporating two alternative interaction techniques: a geometric-semantic zoom that provides smooth transition between overview and detail, and a fisheye distortion that displays the focus and context regions of the scatterplot in a single view. A user study with 24 participants was conducted to compare the usability and efficiency of both techniques when searching a book database containing 7500 items. The study was run on a pen-driven Wacom board simulating a PDA interface. While the results showed no significant difference in task-completion times, a clear majority of 20 users preferred the fisheye view over the zoom interaction. In addition, other dependent variables such as user satisfaction and subjective rating of orientation and navigation support revealed a preference for the fisheye distortion. These findings partly contradict related research and indicate that, when using a small screen, users place higher value on the ability to preserve navigational context than they do on the ease of use of a simplistic, metaphor-based interaction style. 相似文献
Software Quality Journal - Nowadays, systems containing components based on machine learning (ML) methods are becoming more widespread. In order to ensure the intended behavior of a software... 相似文献
The paging algorithm Least Recently Used Second Last Request (LRU-2) was proposed for use in database disk buffering and shown experimentally to perform better than Least Recently Used (LRU). We compare LRU-2 and LRU theoretically, using both the standard competitive analysis and the newer relative worst order analysis. The competitive ratio for LRU-2 is shown to be 2k for cache size k, which is worse than LRU’s competitive ratio of k. However, using relative worst order analysis, we show that LRU-2 and LRU are comparable in LRU-2’s favor, giving a theoretical justification for the experimental results. Many of our results for LRU-2 also apply to its generalization, Least Recently Used Kth Last Request. 相似文献
This paper presents a parallel algorithm for fast word search to determine the set of biological words of an input DNA sequence.
The algorithm is designed to scale well on state-of-the-art multiprocessor/multicore systems for large inputs and large maximum
word sizes. The pattern exhibited by many sequential solutions to this problem is a repetitive execution over a large input
DNA sequence, and the generation of large amounts of output data to store and retrieve the words determined by the algorithm.
As we show, this pattern does not lend itself to straightforward standard parallelization techniques. The proposed algorithm
aims to achieve three major goals to overcome the drawbacks of embarrassingly parallel solution techniques: (i) to impose
a high degree of cache locality on a problem that, by nature, tends to exhibit nonlocal access patterns, (ii) to be lock free
or largely reduce the need for data access locking, and (iii) to enable an even distribution of the overall processing load
among multiple threads. We present an implementation and performance evaluation of the proposed algorithm on DNA sequences
of various sizes for different organisms on a dual processor quad-core system with a total of 8 cores. We compare the performance
of the parallel word search implementation with a sequential implementation and with an embarrassingly parallel implementation.
The results show that the proposed algorithm far outperforms the embarrassingly parallel strategy and achieves a speed-up’s
of up to 6.9 on our 8-core test system. 相似文献