Push-Pull Messaging: a high-performance communication mechanism for commodity SMP clusters

Push-Pull Messaging is a novel messaging mechanism for high-speed interprocess communication in a cluster of symmetric multi-processors (SMP) machines. This messaging mechanism exploits the parallelism in SMP nodes by allowing the execution of communication stages of a messaging event on different processors to achieve maximum performance. Push-Pull Messaging facilitates further improvement on communication performance by employing three optimizing techniques in our design: (1) Cross-Space Zero Buffer provides a unified buffer management mechanism to achieve a copy-less communication for the data transfer among processes within a SMP node. (2) Address Translation Overhead Masking removes the address translation overhead from the critical path in the internode communication. (3) Push-and-Acknowledge Overlapping overlaps the push and acknowledge phases to hide the acknowledge latency. Overall, Push-Pull Messaging effectively utilizes the system resources and improves the communication speed. It has been implemented to support high-speed communication for connecting quad Pentium Pro SMPs with 100 Mbit/s Fast Ethernet.published_or_final_versio

Efficient reliable broadcast for commodity clusters

High-speed collective communication is the key to achieve high-performance computing in parallel computing. In the past, collective operations are usually implemented using unicast operations. We proposed a new architecture EQA (Enhanced Queue Architecture) for implementing high-speed collective operations in a cluster. With the incorporation of EQA and the hardware broadcast facility in network switches, an efficient reliable broadcast operation is implemented in a DP-SMP communication subsystem. With EQA, the computation, memory and network resources can be utilized efficiently. We evaluated the performance of the broadcast operation in a commodity cluster with fast Ethernet connection. We found that the hardware-based broadcast from DP-SMP with EQA outperforms the software-based broadcast operation. The use of EQA in broadcast operation could reduce the memory consumption by almost 40%. DP-SMP with EQA has proven to be an efficient communication mechanism for coupling commodity clusters.published_or_final_versio

Fast rotation center identification methods for video sequences

Rotational motion can often be seen in video. However, comparatively little research has been done to investigate rotational motions in video, whose analysis could be useful. For example, if we can efficiently identify the rotation center of a spinning object, extraction and tracking of it can be made easier by grouping points moving at the same radial speed. It could also improve compression by synthesizing analyzed spin transitions, and help tracking of rotating objects. In this paper, we introduce a set of rotation center location methods using only the motion field constructed during video encoding, along with a few methods for improving their performances. These methods can be implemented using integer operations only. They are up to 1.81 times faster than the traditional circulation analysis method with little sacrifice in accuracy, and are not affected by asymmetric fields caused by translational motions. © 2005 IEEE.published_or_final_versio

An intelligent tropical cyclone eye fix system using motion field analysis

Tropical cyclones (TCs) are weather systems with vast destructive power. Accurate location of their circulation centers, or "eyes", is thus important to forecasters. However, the eye fix process is often done manually in practice. While multiple factors are considered in the process, with subjective elements in these methods, forecasters could disagree. This paper describes a TC eye fix system that uses a novel motion field structure analysis method. It can handle TCs without well-defined structure that are partially out of the image. The systems also adapts user inputs and past results to improve its accuracy. Implemented on a commodity desktop computer, the system can process about 5 images per minute, giving an average error of about 0.16 degrees in latitude/longitude on Mercator projected map for TCs that are completely inside the radar image. This is well within the relative error of about 0.3-0.4 degrees given by different TC warning centers. This TC eye fix system is useful in giving an objective TC center location in contrast to traditional manual analysis. © 2005 IEEE.published_or_final_versio

Chinese herbal medicine in the treatment of acute upper respiratory tract infection: a randomised, double blind, placebo-controlled clinical trial.

published_or_final_versio

Fabrication of multilayer ring transformer

2001-2002 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Optical studies of transparent ferroelectric strontium-barium niobate/silica nanocomposite

Author name used in this publication: C. L. MakAuthor name used in this publication: K. H. Wong2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Pilot project of integration of Chinese medicine (acupuncture) and Western medicine for neurohabilitation of children with acquired brain injury: a study of 2 cases

PURPOSE: To demonstrate if there is any efficacy of integration of Chinese medicine (acupuncture) and western medicine for rehabilitation for two children with acquired brain injury (ABI). METHODS: Two children (M/1 year, with dystonic cerebral palsy, cortical visual impairment and global developmental delay due to acute encephalitis; and M/12 years, with spastic tetraplegia, cortical visual impairment, and severe mental retardation due to hypoxic-ischaemic encephalopathy related to hypertrophic cardiomyopathy) were enrolled into our pilot programme which had started as the ‘First Integrated Chinese Medicine and Western Medicine for Neurorehabilitation of Children with Traumatic or Acquired Brain Injury under the Hospital Authority’ in June 2008. Both of them received daily acupuncture treatment and conventional neurohabilitation programme for 4 months. Pre- and post-assessment were performed for both cases. Deoxyglucose PET scan of the brain, parental daily reports for any change after each acupuncture session were monitored. Objective outcome measures were performed by the Neurohabilitation Team with allied health disciplines including physiotherapist, occupational therapist, optometrist, audiologist, speech therapist and clinical psychologist in pre- and post-acupuncture treatment using objective outcome measures including Modified Ashworth Spasticity Scale, CVI assessment, Video Fluoroscopic Swallow Study (VFSS) and Functional Independence Measure of Children (WeeFIM). Videos were taken by blind assessors. RESULTS: PET scan of the brain showed mild-to-moderate increase in glucose uptake for both cases. Videos and clinical outcome measures showed improvement in vision and other parameters. CONCLUSIONS: A short and intensive course of acupuncture can be effective in improving visual and functional outcome for children with ABI. Further research is underway to assess the practicability of organising this model of integration of Chinese medicine (acupuncture) and western medicine for neurohabilitation of children with ABI in Hong Kong.published_or_final_versio

Outcome for Hong Kong residents undergoing cadaveric liver transplantation in mainland China

Objective. To review the outcome for Hong Kong residents undergoing cadaveric liver transplantation in mainland China. Design. Retrospective study. Setting. Liver Transplant Centre, university teaching hospital, Hong Kong. Subjects and methods. A retrospective review of medical records was undertaken for patients at Queen Mary Hospital who underwent cadaveric liver transplantation in China between 1 January 1997 and 31 December 2001. Results. Fifteen patients from Queen Mary Hospital underwent cadaveric liver transplantation in China during the study period. Eleven were men and four were women. Their mean age was 51 years. Disease indications included hepatitis B-related liver cirrhosis (n=7), hepatitis B-related liver cirrhosis with hepatocellular carcinoma (n=5), hepatitis C-related liver cirrhosis (n=1), hepatitis C-related liver cirrhosis with hepatocellular carcinoma (n=1), and polycystic liver and kidney disease (n=1). Nine patients were already waiting for liver transplantation at Queen Mary Hospital, and two of the nine patients were on the 'urgent' list. The overall survival rate was 80.0% at 6 months and 73.3% at 12 months. There were four (27%) deaths, two of which occurred in China. Of the 11 surviving patients, nine (82%) developed complications. Nineteen complications were seen in the 13 patients who were managed in Hong Kong following their return from China. Infective and biliary complications accounted for 58% and 26% of complications, respectively. Major complications necessitated prolonged hospitalisation for four patients and two required further laparotomy. Conclusion. Although cadaveric liver transplantation in China is an option for Hong Kong residents, patients and clinicians should be aware of the possible outcomes and resource implications.published_or_final_versio