1. |
- Khan, Salman Naeem, et al.
(author)
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Optimal design for a flat-top AWG demultiplexer by using a fast calculation method based on a Gaussian beam approximation
- 2006
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In: Optics Communications. - : Elsevier BV. - 0030-4018 .- 1873-0310. ; 262:2, s. 175-179
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Journal article (peer-reviewed)abstract
- Passband broadening of an AWG (array waveguide grating) demultiplexer with an MMI (multimode interference) coupler connected at the end of a tapered input waveguide is considered. An explicit formula based on the field propagation of an approximate Hermit-Gaussian beam is used to calculate quickly and reliably the spectral response of the AWG demultiplexer. The widths of the input waveguide, the output waveguides and the MMI coupler are optimized. The optimal design is verified with the experimental measurement.
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3. |
- Gao, Feng, et al.
(author)
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Visible-light photocatalytic properties of weak magnetic BiFeO3 nanoparticles
- 2007
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In: Advanced Materials. - : Wiley-VCH Verlag. - 0935-9648 .- 1521-4095. ; 19:19, s. 2889-2892
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Journal article (peer-reviewed)abstract
- Polycrystalline BiFeO3 nanoparticles (size 80-120 nm) are prepared by a simple sol-gel technique. Such nanoparticles are very efficient for photocatalytic decomposition of organic contaminants under irradiation from ultraviolet to visible frequencies. The BiFeO3 nanoparticles also demonstrate weak ferromagnetism of about 0.06 mu(B)/Fe at room temperature, in good agreement with theoretical calculations.
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4. |
- Liu, Jin-ming, et al.
(author)
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Mid-term effects of lung volume reduction surgery on pulmonary function in patients with chronic obstructive pulmonary disease
- 2007
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In: Chinese Medical Journal. - 0366-6999. ; 120:8, s. 658-662
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Journal article (peer-reviewed)abstract
- Background Now lung volume reduction surgery (LVRS) has become one of the most effective methods for the management of some cases of severe chronic obstructive pulmonary disease (COPD). We evaluated the mid-term effects of LVRS on pulmonary function in patients with severe COPD. Methods Ten male patients with severe COPD aged 38-70 years underwent LVRS and their pulmonary function was assessed before, 3 months and 3 years after surgery. The spirometric and gas exchange parameters included residual volume, total lung capacity, inspiratory capacity, forced vital capacity, forced expiratory volume in one second, diffusion capacity for CO, and arterial blood gas. A 6-minute walk distance (6MWD) test was performed. Results As to preoperative assessment, most spirometric parameters and 6MWD were significantly improved after 3 months and slightly 3 years after LVRS. Gas exchange parameters were significantly improved 3 months after surgery, but returned to the preoperative levels after 3 years. Conclusions LVRS may significantly improve pulmonary function in patients with severe COPD indicating for LVRS. Mid-term pulmonary function 3 years after surgery can be decreased to the level at 3 months after surgery. Three years after LVRS, lung volume and pulmonary ventilation function can be significantly improved, but the improvement in gas exchange function was not significant.
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5. |
- Liu, Ming, 1982-
(author)
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A High-end Reconfigurable Computation Platform for Particle Physics Experiments
- 2008
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Licentiate thesis (other academic/artistic)abstract
- Modern nuclear and particle physics experiments run at a very high reaction rate and are able to deliver a data rate of up to hundred GBytes/s. This data rate is far beyond the storage and on-line analysis capability. Fortunately physicists have only interest in a very small proportion among the huge amounts of data. Therefore in order to select the interesting data and reject the background by sophisticated pattern recognition processing, it is essential to realize an efficient data acquisition and trigger system which results in a reduced data rate by several orders of magnitude. Motivated by the requirements from multiple experiment applications, we are developing a high-end reconfigurable computation platform for data acquisition and triggering. The system consists of a scalable number of compute nodes, which are fully interconnected by high-speed communication channels. Each compute node features 5 Xilinx Virtex-4 FX60 FPGAs and up to 10 GBytesDDR2 memory. A hardware/software co-design approach is proposed to develop custom applications on the platform, partitioning performance-critical calculation to the FPGA hardware fabric while leaving flexible and slow controls to the embedded CPU plus the operating system. The system is expected to be high-performance and general-purpose for various applications especially in the physics experiment domain. As a case study, the particle track reconstruction algorithm for HADES has been developed and implemented on the computation platform in the format of processing engines. The Tracking Processing Unit (TPU) recognizes peak bins on the projection plane and reconstructs particle tracks in realtime. Implementation results demonstrate its acceptable resource utilization and the feasibility to implement the module together with the sys-tem design on the FPGA. Experimental results show that the online track reconstruction computation achieves 10.8 - 24.3 times performance acceleration per TPU module when compared to the software solution on a Xeon2.4 GHz commodity server.
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6. |
- Liu, Ming, et al.
(author)
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A Reconfigurable Design Framework for FPGA Adaptive Computing
- 2009
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In: 2009 INTERNATIONAL CONFERENCE ON RECONFIGURABLE COMPUTING AND FPGAS. - : IEEE. - 9781424452934 ; , s. 439-444
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Conference paper (peer-reviewed)abstract
- Partial Reconfiguration (PR) offers the possibility to adaptively change part of the FPGA design without stopping the remaining system. In this paper, we present a comprehensive framework for adaptive computing, in which design key points of hardware processes, system interconnections, Operating Systems (OS), device drivers, scheduler software as well as context switching are respectively concerned in different hardware/software layers. A case study is discussed to demonstrate an example of swapping a Flash memory controller and an SRAM controller in response to diverse memory access needs. Result analysis reveals a more efficient resource utilization of 52.1% I/O pads, 86.5% LUTs and 81.3% Flip-Flops, when compared to the static design with same functionalities. A small reconfiguration overhead of context switching is measured within the range from hundreds of microseconds to milliseconds. Moreover, technical perspectives are analyzed and it is foreseen to obtain great benefits with the proposed design framework in object applications of particle physics experiments.
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7. |
- Liu, Ming, et al.
(author)
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ATCA-based Computation Platform for Data Acquisition and Triggering in Particle Physics Experiments
- 2008
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In: 2008 INTERNATIONAL CONFERENCE ON FIELD PROGRAMMABLE AND LOGIC APPLICATIONS, VOLS 1 AND 2. ; , s. 287-292
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Conference paper (peer-reviewed)abstract
- An ATCA-based computation platform for data acquisition and trigger applications in nuclear and particle physics experiments has been developed. Each Compute Node (CN) which appears as a Field Replaceable Unit (FRU) in an ATCA shelf, features 5 Xilinx Virtex-4 FX60 FPGAs and up to 10 GBytes DDR2 memory. Connectivity is provided with 8 optical links and 5 Gigabit Ethernet ports, which are mounted on each board to receive data from detectors and forward results to outer shelves or PC farms with attached mass storage. Fast point-to-point on-board interconnections between FPGAs as well as the full-mesh shelf backplane provide flexibility and high bandwidth to partition algorithms and correlate results among them. The system represents a highly reconfigurable and scalable solution for multiple applications.
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8. |
- Liu, Ming, et al.
(author)
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Hardware/Software co-design of a general-purpose computation platform in particle physics
- 2007
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In: ICFPT 2007. - 9781424414710 ; , s. 177-183
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Conference paper (peer-reviewed)abstract
- In this paper we present a hardware/software co-design based computation platform for online data processing in particle physics experiments. Our goal is to ease and accelerate the development and make it universal and scalable for multiple applications, on the premise of guaranteeing high communicating and processing capabilities. The entire computation network consists of quite a few interconnected compute nodes, each of which has multiple FPGAs to implement specific algorithms for data processing. High-speed communication features including RocketIO multi-gigabit transceiver and Gigabit Ethernet are supported by FPGAs to construct internal and external connections. An embedded Linux operating system is fitted on the PowerPC CPU core inside the Xilinx Virtex-4 FX FPGA. Thus programmers can access hardware resources via device drivers and write application programs to manage the system from the high level. Furthermore measurements have been executed using the development board to investigate both communicating and processing performances of the system. Results show that the computation platform is able to communicate at a UDP/IP data rate of around 400 Mbps per Ethernet link, and the event selection engine could process an event rate of 25%.
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9. |
- Liu, Ming, et al.
(author)
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Run-time Partial Reconfiguration Speed Investigation and Architectural Design Space Exploration
- 2009
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In: FPL 09. - 9781424438914 ; , s. 498-502
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Conference paper (peer-reviewed)abstract
- Run-time Partial Reconfiguration (PR) speed is significant in applications especially when fast IP core switching is required. In this paper, we propose to use Direct Memory Access (DMA), Master (MST) burst, and a dedicated Block RAM (BRAM) cache respectively to reduce the reconfiguration time. Based on the Xilinx PR technology and the Internal Configuration Access Port (ICAP) primitive in the FPGA fabric, we discuss multiple design architectures and thoroughly investigate their performance with measurements for different partial bitstream sizes. Compared to the reference OPB_HWICAP and XPS_HWICAP designs, experimental results show that DMA_HWICAP and MST_HWICAP reduce the reconfiguration time by one order of magnitude, with little resource consumption overhead. The BRAM_HWICAP design can even approach the reconfiguration speed limit of the ICAP primitive at the cost of large Block RAM utilization.
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10. |
- Liu, Ming, et al.
(author)
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System-on-an-FPGA Design for Real-time Particle Track Recognition and Reconstruction in Physics Experiments
- 2008
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In: 11TH EUROMICRO CONFERENCE ON DIGITAL SYSTEM DESIGN - ARCHITECTURES, METHODS AND TOOLS. - LOS ALAMITOS : IEEE COMPUTER SOC. ; , s. 599-605
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Conference paper (peer-reviewed)abstract
- In particle physics experiments, the momenta of charged particles are studied by observing their deflection in a magnetic field. Dedicated detectors measure the particle tracks and complex algorithms are required for track recognition and reconstruction. This CPU-intensive task is usually implemented as off-line software running on PC clusters. In this paper we present a system-on-chip design for the track recognition and reconstruction based on modern FPGA technologies. The basic principle of the algorithm is polled from software into the FPGA fabric. The fundamental architecture of the tracking processor is described in detail. Working as processing engines in compute nodes, the tracking processor contributes to recognize potential track candidates in real-time and promotes the selection efficiency of the data acquisition and trigger system. Our design study shows that the tracking module can be integrated in a single Xilinx Virtex-4 FX60 FPGA. The processing capability of the design is about 16.7K sub-events per second per module with our experimental setup, which achieves 20 times speedup compared to the software implementation.
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11. |
- Liu, Ming, et al.
(author)
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Trigger algorithm development on FPGA-based Compute Nodes
- 2009
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In: 2009 16th IEEE-NPSS Real Time Conference. - New York : IEEE. - 9781424457960 ; , s. 478-484
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Conference paper (peer-reviewed)abstract
- Based on the ATCA computation architecture and Compute Nodes (CN), investigation and implementation work has been being executed for HADES and PANDA trigger algorithms. We present our designs for HADES track reconstruction processing, Cherenkov ring recognition, Time-Of-Flight processing, electromagnetic shower recognition.. and the PANDA straw tube tracking algorithm. They will appear as co-processors in the uniform system design to undertake the detector-specific computing. The algorithm principles will be explained and hardware designs are described in the paper. The current progress reveals the feasibility to implement these algorithms on FPGAs. Also experimental results demonstrate the performance speedup when compared to alternative software solutions, as well as the potential capability of high-speed parallel/pipelined processing in Data Acquisition and Trigger systems.
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12. |
- Lu, Zhonghai, et al.
(author)
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Layered switching for networks on chip
- 2007
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In: 2007 44th ACM/IEEE Design Automation Conference, Vols 1 And 2. - 9781595937711 ; , s. 122-127
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Conference paper (peer-reviewed)abstract
- We present and evaluate a novel switching mechanism called layered switching. Conceptually, the layered switching implements wormhole on top of virtual cut-through switching. To show the feasibility of layered switching, as well as to confirm its advantages, we conducted an RTL implementation study based on a canonical wormhole architecture. Synthesis results show that our strategy suggests negligible degradation in hardware speed (1%) and area overhead (7%). Simulation results demonstrate that it achieves higher throughput than wormhole alone while significantly reducing the buffer space required at network nodes when compared with virtual cut-through.
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13. |
- Tian, Haining, et al.
(author)
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A triphenylamine dye model for the study of intramolecular energy transfer and charge transfer in dye-sensitized solar cells.
- 2008
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In: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 18:21, s. 3461-3468
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Journal article (peer-reviewed)abstract
- A novel dye (2TPA-R), contg. two triphenylamine (TPA) units connected by a vinyl group and rhodanine-3-acetic acid as the electron acceptor, is designed and synthesized successfully to reveal the working principles of org. dye in dye-sensitized solar cells (DSSCs). 2TPA and TPA-R, which consist of two TPA units connected by vinyl and a TPA unit linked with rhodanine-3-acetic acid, resp., are also synthesized as refs. to study the intramol. energy transfer (EnT) and charge transfer (ICT) processes of 2TPA-R in CH2Cl2 soln. and on a TiO2 surface. The results suggest that the intramol. EnT and ICT processes show a pos. effect on the performance of DSSCs. However, the flexible structure and less-adsorbed amt. of dye on TiO2 may make it difficult to improve the efficiency of DSSCs. This study on intramol. EnT and ICT processes acts as a guide for the design and synthesis of efficient org. dyes in the future. [on SciFinder(R)]
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14. |
- Wang, Qiang, et al.
(author)
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Hardware/Software Co-design of an ATCA-based Computation Platform for Data Acquisition and Triggering
- 2009
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In: 16th IEEE NPSS Real Time Conference. - 9781424457960 ; , s. 485-489
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Conference paper (peer-reviewed)abstract
- An ATCA-based computation platform for data acquisition and trigger(TDAQ) applications has been developed for multiple future projects such its PANDA. HADES, and BESIII. Each Compute Node (CN) appears as one (if the fourteen Field Replaceable Units (FRU) in an ATCA shelf, which in total features a high performance of 1890 Clips inter-FPGA on-board channels, 1456 Gbps inter-board backplane connections, 728 Gbps full-duplex optical links, 70 Gbps Ethernet. 140 GBytes DDR2 SDRAM. and all computing resources of 70 Xilinx Virtex-4 FX60 FPGAs. Corresponding to (the system architecture, a hardware/software co-design approach is proposed to ease and accelerate the development for different experiments. In the uniform system design. application-specific computation is to be implemented as customized hardware co-processors, while the embedded PowerPC processor takes charge of flexible slow controls and transmission protocol processing.
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