Lightweight process migration and memory prefetching in openMosix

We propose a lightweight process migration mechanism and an adaptive memory prefetching scheme called AMPoM (Adaptive Memory Prefetching in openMosix), whose goal is to reduce the migration freeze time in openMosix while ensuring the execution efficiency of migrants. To minimize the freeze time, our system transfers only a few pages to the destination node during process migration. After the migration, AMPoM analyzes the spatial locality of memory access and iteratively prefetches memory pages from remote to hide the latency of inter-node page faults. AMPoM adopts a unique algorithm to decide which and how many pages to prefetch. It tends to prefetch more aggressively when a sequential access pattern is developed, when the paging rate of the process is high or when the network is busy. This advanced strategy makes AMPoM highly adaptive to different application behaviors and system dynamics. The HPC Challenge benchmark results show that AMPoM can avoid 98% of migration freeze time while preventing 85-99% of page fault requests after the migration. Compared to openMosix which does not have remote page fault, AMPoM induces a modest overhead of 0-5% additional runtime. When the working set of a migrant is small, AMPoM outperforms openMosix considerably due to the reduced amount of data transfer. These results indicate that by exploiting memory access locality and prefetching, process migration can be a lightweight operation with little software overhead in remote paging. ©2008 IEEE.published_or_final_versionThe 2008 IEEE International Symposium on Parallel and Distributed Processing (IPDPS 2008), Miami, FL., 14-18 April 2008. In Proceedings of the 22nd IPDPS, 2008, p. 1-1

Robot-assisted versus standard laparoscopic partial nephrectomy: comparison of perioperative outcomes from a single institution

OBJECTIVE: To evaluate the perioperative outcomes of robot-assisted laparoscopic partial nephrectomy and standard laparoscopic partial nephrectomy in a teaching hospital. DESIGN: Retrospective study. SETTING: Division of Urology, Department of Surgery, Queen Mary and Tung Wah hospitals, Hong Kong. PATIENTS: The first 10 consecutive patients who had robot-assisted laparoscopic partial nephrectomy for renal tumours between January 2008 and September 2009 with prospective data collection were evaluated. Their outcomes were compared with the last 10 consecutive patients in our database, who had standard laparoscopic partial nephrectomy between November 2004 and October 2007. MAIN OUTCOME MEASURES: Demographics, tumour characteristics, perioperative outcomes, renal function, and pathological outcomes. RESULTS: There were no differences between the groups with regard to age (63 vs 56 years; P=0.313) and tumour size (2.7 vs 2.8 cm; P=0.895). No significant difference was found between the two groups with respect to the operating room time (376 vs 361 min; P=0.722), estimated blood loss (329 vs 328 mL; P=0.994), and length of hospital stay (7 vs 14 days; P=0.213). A statistically significant shorter mean warm ischaemic time for the robot-assisted group was noted (31 vs 40 minutes; P=0.032). Respective renal functional outcomes as shown by the difference between day 0 and day 60 serum creatinine levels were comparable (+10 vs +7 mmol/L; P=0.605). In both groups, there were no intra-operative complications or instances of surgical margin tumour involvement. Three patients endured postoperative complications in the standard laparoscopic group (a perinephric haematoma, urine leakage, and lymph leakage) compared with one in the robot-assisted group (a perinephric haematoma). These complications all resolved with conservative treatment. CONCLUSIONS: Robot-assisted laparoscopic partial nephrectomy is a technically feasible alternative to standard laparoscopic partial nephrectomy, and provides comparable results. Robot-assisted laparoscopic partial nephrectomy appears to offer the advantage of decreased warm ischaemic time. Longer follow-up is required to assess renal function and oncological outcomes. Further experience and randomised trials are necessary to compare robot-assisted with standard laparoscopic partial nephrectomy.published_or_final_versio

Scalable group-based checkpoint/restart for large-scale message-passing systems

The ever increasing number of processors used in parallel computers is making fault tolerance support in large-scale parallel systems more and more important. We discuss the inadequacies of existing system-level checkpointing solutions for message-passing applications as the system scales up. We analyze the coordination cost and blocking behavior of two current MPI implementations with checkpointing support. A group-based solution combining coordinated checkpointing and message logging is then proposed. Experiment results demonstrate its better performance and scalability than LAM/MPI and MPICH-VCL. To assist group formation, a method to analyze the communication behaviors of the application is proposed. ©2008 IEEE.published_or_final_versio

Improving efficiency roll-off in organic light emitting devices with a fluorescence-interlayer-phosphorescence emission architecture

Organic light emitting devices (OLEDs) with a fluorescence-interlayer- phosphorescence emission layer structure (FIP EML) has been proposed to solve the efficiency roll-off issue effectively. Efficient green OLED based on FIP EML exhibiting only 26% roll-off in the luminance efficiency, which is lower than the typical roll-off of 51% for conventional phosphorescent OLEDs with single EML operated at 5-150 mA/cm2 range, has been demonstrated. Such enhancement should be attributed to the improved carrier balance, the exciton redistribution in recombination zone, the suppression of nonradiative exciton quenching processes, and the elimination of energy transfer loss offered by the FIP EML structure. © 2009 American Institute of Physics.published_or_final_versio

Efficacy of psychosocial intervention in improving quality of life and psychological well-being of Chinese patients with colorectal cancer: a randomised controlled trial.

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Randomized controlled trial of the effect of phytosterols-enriched low-fat milk on lipid profile in Chinese

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Typical collapse modes of confined masonry buildings under strong earthquake loads

Confined masonry structures are a widely applied structural system in many developing countries. During the past Wenchuan Earthquake in 2008, numerous confined masonry buildings collapsed, while many others suffered damage. This study reviews the construction practices of confined masonry buildings in China. Simple models and hand calculation methods are proposed for quantifying the tearing failure of diaphragms, the tensile failure of tie-columns and the sway-mode strength of masonry buildings. The results indicate very good agreement with field observations. The seismic measures that are stipulated in the seismic design codes are very effective for increasing the strength and integrity, but not the ductility of masonry buildings. For those buildings that survived the earthquake, strength rather than ductility protected the confined masonry from collapse or serious damage. Design recommendations are suggested for preventing various types of premature failures and enhancing the lateral strength of masonry buildings. © Su et al.published_or_final_versio

Exhaled nitric oxide predicts lung function but not quality of life in subjects with non-small cell lung cancer

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An adaptive multipath protocol for efficient IP handoff in mobile wireless networks

Achieving IP handoff with a short latency and minimal packet loss is essential for mobile devices that roam across IP subnets. Many existing solutions require changes to be made to the network or transport layer, and they tend to suffer from long handoff latency in either soft or hard handoff scenario, or both; and some are difficult to deploy in practice. We propose a new protocol, called the adaptive multipath protocol, to achieve efficient IP handoff. Based on link-layer signal strength measurements, two different schemes are used to handle soft and hard handoff respectively. Seamless IP handoff is achieved by using multiple transport layer connections on top of persistent link-layer connectivity during soft handoff. To achieve low handoff latency during hard handoff, a set of distributed sessions repositories (SRs), which are independent of the end hosts, are employed. Simulation results clearly support our claims. In particular, the latency for hard handoff is found to be as low as 50% of that of Fast handoff. © 2006 IEEE.published_or_final_versio

Synchronisation and commonalities in metropolitan housing market cycles

This paper examines the degree of commonalities present in the cyclical behavior of the eight largest metropolitan housing markets in Australia. Using two techniques originally in the business cycle literature we consider the degree of synchronization present and secondly decompose the series’ into their permanent and cyclical components. Both empirical approaches reveal similar results. Sydney and Melbourne are closely related to each other and are relatively segmented from the smaller metropolitan areas. In contrast, there is substantial evidence of commonalities in the cyclical behavior of the remaining cities, especially those on the Eastern and Southern coasts of Australia