Cache Optimization for H.264/AVC Motion Compensation

In this letter, we propose a cache organization that substantially reduces the memory bandwidth of motion compensation (MC) in the H.264/AVC decoders. To reduce duplicated memory accesses to P and B pictures, we employ a four-way set-associative cache in which its index bits are composed of horizontal and vertical address bits of the frame buffer and each line stores an 8 × 2 pixel data in the reference frames. Moreover, we alleviate the data fragmentation problem by selecting its line size that equals the minimum access size of the DDR SDRAM. The bandwidth of the optimized cache averaged over five QCIF IBBP image sequences requires only 129% of the essential bandwidth of an H.264/AVC MC

Reusable Component IP Design using Refinement-based Design Environment

We propose a method of enhancing the reusability of the component IPs by separating communication and computation for a system function. In this approach, we assume that the component designers describe mainly the computation part of the component, and the system designer can construct the communication part by using our refinement-based design environment. Moreover, we introduced a concept of the Communication Architecture Template Tree (CATree), which helps IP designers to effectively separate computation and communication for a system function. We confirmed that this approach is effective by applying it to a H.264 decoder design

A mixed-level virtual prototyping environment for refinement-based design environment

The Communication Architecture Template Tree (CATtree) is an abstraction of the specific range of communication functions and architectures, which can facilitate system function capture and communication architecture refinement. In this paper, we explain a TLM-RTL-SW mixedlevel simulation environment that is useful for the functional verification of partially refined system models. We employed SystemC, GNU Gdb and a HDL simulator for the simulation of CATtree-based TLM, SW and HW, respectively. We also employed a new operating system, DEOS so that each SystemC-based TLMs can be cross-compiled to be executed as software models on the target processors. We evaluated the flexibility and simulation performance of the virtual simulation environment with an H.264 decoder design example

Implementation of a H.264 decoder with Template-based Communication Refinement

We described an H.264 decoder implemented with our design methodology, in which a system function model of transaction level is first captured in SystemC and refined into RTL with a library of communication templates. We determined its communication architecture by exploring the design space with template-based communication refinement to meet its requirement of decoding VGA 30 frames per second at a clock frequency of 50MHz

3D reverse-time migration using the acoustic wave equation: An experience with the SEG/EAGE data set

Kirchhoff is the most commonly used 3D prestack migration algorithm because of its speed and other economic advantages, but it uses a high-frequency ray approximation to the wave equation and, therefore, has difficulties in imaging complex geologic structures where multipathing occurs (e.g., beneath rugose horizons such as faulted salt domes where traveltime calculations become difficult). In contrast to Kirchhoff migration, reverse-time migration computes numerical solutions to the complete wave equation and, therefore, is potentially more accurate. But this technique is not popular in the industry because it is computationally intensive and expensive. However, we felt some recent developments would allow 3D reverse-time migration to be done relatively inexpensively on PC-based distributed memory clusters. In order to examine this hypothesis, we implemented reverse-time migration on a PC cluster by using higher-order accuracy finite difference algorithms (Wu et al., 1996), an excitation time approach (Chang and McMechan, 1994), and variable grids (Mufti et al., 1996) to reduce memory and CPU time. We then used the pseudo-spectral method—following Gazdag (1981), Kosloff and Baysal (1982), and Fornberg (1987)—to further reduce CPU time and core memory requirements. In this article, we compare our reverse-time migration images with first-arrival Kirchhoff migration images to demonstrate that 3D reverse-time migration can produce high fidelity images under the PC-based distributed memory cluster machine.The authors thank the financial supporters of the Brain Korea 21 Project and the National Research Laboratory project of the Ministry of Science and Technology

LsrR-Mediated Quorum Sensing Controls Invasiveness of Salmonella typhimurium by Regulating SPI-1 and Flagella Genes

Bacterial cell-to-cell communication, termed quorum sensing (QS), controls bacterial behavior by using various signal molecules. Despite the fact that the LuxS/autoinducer-2 (AI-2) QS system is necessary for normal expression of Salmonella pathogenicity island-1 (SPI-1), the mechanism remains unknown. Here, we report that the LsrR protein, a transcriptional regulator known to be involved in LuxS/AI-2-mediated QS, is also associated with the regulation of SPI-1-mediated Salmonella virulence. We determined that LsrR negatively controls SPI-1 and flagella gene expressions. As phosphorylated AI-2 binds to and inactivates LsrR, LsrR remains active and decreases expression of SPI-1 and flagella genes in the luxS mutant. The reduced expression of those genes resulted in impaired invasion of Salmonella into epithelial cells. Expression of SPI-1 and flagella genes was also reduced by overexpression of the LsrR regulator from a plasmid, but was relieved by exogenous AI-2, which binds to and inactivates LsrR. These results imply that LsrR plays an important role in selecting infectious niche of Salmonella in QS dependent mode

Cache Optimization for H.264/AVC Motion Compensation

In this letter, we propose a cache organization that substantially reduces the memory bandwidth of motion compensation (MC) in the H.264/AVC decoders. To reduce duplicated memory accesses to P and B pictures, we employ a four-way set-associative cache in which its index bits are composed of horizontal and vertical address bits of the Frame buffer and each line stores in 8 x 2 pixel data in the reference frames. Moreover, we alleviate the data fragmentation problem by selecting its line size that equals the minimum access size of the DDR SDRAM. The bandwidth of the optimized cache averaged over five QCIF IBBP image sequences requires only 129% of the essential bandwidth of an H.264/AVC MC.

A mixed-level virtual prototyping environment for SystemC-based design methodology

Weproposeaflexiblemixed-levelvirtualprototypingenvironment,wheremodelsindifferent abstraction levelssuchastransactionlevel,register-transferlevel,andsoftwarelevelcanbeco- simulatedtogether.Intheproposedenvironment,thedesignersshouldcaptureatransactionlevel systemmodelbeforehardware–softwarepartitioning,fromwhichmixed-levelvirtualprototyping models canberefinedwithpre-definedandpre-verifiedcommunicationprimitives.Weexplainseveral techniquesemployedintheenvironmentsuchasIDportsforsoftwaretemplateefficiency,abstraction adaptersinSystemCformixedlevelsimulation,andtrace-drivensimulationforfasterperformance evaluation.Moreover,transactionleveldescriptionsinSystemCcanbecompiledandexecutedas softwaretogetherwiththeDEOS,whichisanoperatingsystemthatprovidesSystemCAPIs.We comparedthesimulationspeedofseveralmixed-levelvirtualprototypesofaH.264decodertoshowthe effectiveness oftheproposedenvironment

Fabrication of a Cell-Friendly Poly(dimethylsiloxane) Culture Surface via Polydopamine Coating

In this study, we fabricated a poly(dimethylsiloxane) (PDMS) surface coated with polydopamine (PDA) to enhance cell adhesion. PDA is well known for improving surface adhesion on various surfaces due to the abundant reactions enabled by the phenyl, amine, and catechol groups contained within it. To confirm the successful surface coating with PDA, the water contact angle and X-ray photoelectron spectroscopy were analyzed. Human umbilical vein endothelial cells (HUVECs) and human-bone-marrow-derived mesenchymal stem cells (MSCs) were cultured on the PDA-coated PDMS surface to evaluate potential improvements in cell adhesion and proliferation. HUVECs were also cultured inside a cylindrical PDMS microchannel, which was constructed to mimic a human blood vessel, and their growth and performance were compared to those of cells grown inside a rectangular microchannel. This study provides a helpful perspective for building a platform that mimics in vivo environments in a more realistic manner