GAMER with out-of-core computation

GAMER is a GPU-accelerated Adaptive-MEsh-Refinement code for astrophysical simulations. In this work, two further extensions of the code are reported. First, we have implemented the MUSCL-Hancock method with the Roe's Riemann solver for the hydrodynamic evolution, by which the accuracy, overall performance and the GPU versus CPU speed-up factor are improved. Second, we have implemented the out-of-core computation, which utilizes the large storage space of multiple hard disks as the additional run-time virtual memory and permits an extremely large problem to be solved in a relatively small-size GPU cluster. The communication overhead associated with the data transfer between the parallel hard disks and the main memory is carefully reduced by overlapping it with the CPU/GPU computations.Comment: 4 pages, 4 figures, conference proceedings of IAU Symposium 270 (eds. Alves, Elmegreen, Girart, Trimble

Graphic-Card Cluster for Astrophysics (GraCCA) -- Performance Tests

In this paper, we describe the architecture and performance of the GraCCA system, a Graphic-Card Cluster for Astrophysics simulations. It consists of 16 nodes, with each node equipped with 2 modern graphic cards, the NVIDIA GeForce 8800 GTX. This computing cluster provides a theoretical performance of 16.2 TFLOPS. To demonstrate its performance in astrophysics computation, we have implemented a parallel direct N-body simulation program with shared time-step algorithm in this system. Our system achieves a measured performance of 7.1 TFLOPS and a parallel efficiency of 90% for simulating a globular cluster of 1024K particles. In comparing with the GRAPE-6A cluster at RIT (Rochester Institute of Technology), the GraCCA system achieves a more than twice higher measured speed and an even higher performance-per-dollar ratio. Moreover, our system can handle up to 320M particles and can serve as a general-purpose computing cluster for a wide range of astrophysics problems.Comment: Accepted for publication in New Astronom

Discovering important factors of intangible firm value by association rules

It is very important for investors to understand the critical factors affecting the value of firms before making investments. In knowledge-based economy, the method for creating firm value transfers from traditional physical assets to intangible knowledge. As intangible assets value is an important part of firm value, valuation of intangible assets becomes a widespread topic of interest in the future of economy. This paper applies association rules, one data mining technique, to discover critical factors affecting firm value in Taiwan and to provide a more flexible model than the traditional regression method. Based on collecting related factors found in literature, the results indicate that R&D intensity, family, participation in management, pyramids, profitability, and dividend are the six important factors, in which some are consistent with significant important variables in prior literature, but most of them are unique for Taiwan, one emerging economy

A peroxiredoxin cDNA from Taiwanofungus camphorata: role of Cys31 in dimerization

Peroxiredoxins (Prxs) play important roles in antioxidant defense and redox signaling pathways. A Prx isozyme cDNA (TcPrx2, 745 bp, EF552425) was cloned from Taiwanofungus camphorata and its recombinant protein was overexpressed. The purified protein was shown to exist predominantly as a dimer by sodium dodecyl sulfate-polyacrylamide gel electrolysis in the absence of a reducing agent. The protein in its dimeric form showed no detectable Prx activity. However, the protein showed increased Prx activity with increasing dithiothreitol concentration which correlates with dissociation of the dimer into monomer. The TcPrx2 contains two Cys residues. The Cys(60) located in the conserved active site is the putative active peroxidatic Cys. The role of Cys(31) was investigated by site-directed mutagenesis. The C31S mutant (C(31) → S(31)) exists predominantly as a monomer with noticeable Prx activity. The Prx activity of the mutant was higher than that of the corresponding wild-type protein by nearly twofold at 12 μg/mL. The substrate preference of the mutant was H2O2 > cumene peroxide > t-butyl peroxide. The Michaelis constant (K M) value for H2O2 of the mutant was 0.11 mM. The mutant enzyme was active under a broad pH range from 6 to 10. The results suggest a role of Cys(31) in dimerization of the TcPrx2, a role which, at least in part, may be involved in determining the activity of Prx. The C(31) residue does not function as a resolving Cys and therefore the TcPrx2 must follow the reaction mechanism of 1-Cys Prx. This TcPrx2 represents a new isoform of Prx family

Use of an open-source CAD software program and additive manufacturing technology to design and fabricate a definitive cast for retrofitting a crown to an existing removable partial denture

This technical report describes a digital process for designing and fabricating a stackable definitive cast and die system to facilitate the fabrication of a new surveyed crown to retrofit to a removable partial denture (RPD). By using an open-source computer-aided design (CAD) software program, this technique provides an economical option for dental clinicians and laboratory technicians to use intraoral scans and design a stackable definitive cast and die system with minimal financial investment in the CAD software. In addition, this technique provides the advantage of a conventional indirect technique in that it can create a definitive cast with an RPD clasp assembly ready for the dental technician to properly contour the new surveyed crown, but without the need for the patient to be without the RPD during the process