A block-diagonal structured model reduction scheme for power grid networks

We propose a block-diagonal structured model order reduction (BDSM) scheme for fast power grid analysis. Compared with existing power grid model order reduction (MOR) methods, BDSM has several advantages. First, unlike many power grid reductions that are based on terminal reduction and thus error-prone, BDSM utilizes an exact column-by-column moment matching to provide higher numerical accuracy. Second, with similar accuracy and macromodel size, BDSM generates very sparse block-diagonal reduced-order models (ROMs) for massive-port systems at a lower cost, whereas traditional algorithms such as PRIMA produce full dense models inefficient for the subsequent simulation. Third, different from those MOR schemes based on extended Krylov subspace (EKS) technique, BDSM is input-signal independent, so the resulting ROM is reusable under different excitations. Finally, due to its blockdiagonal structure, the obtained ROM can be simulated very fast. The accuracy and efficiency of BDSM are verified by industrial power grid benchmarks. © 2011 EDAA.published_or_final_versionDesign, Automation and Test in Europe Conference and Exhibition (DATE 2011), Grenoble, France, 14-18 March 2011. In Design, Automation, and Test in Europe Conference and Exhibition Proceedings, 2011, p. 44-4

Effective Community Search over Large Spatial Graphs

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Effective Community Search for Large Attributed Graphs

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C-Explorer: Browsing Communities in Large Graphs

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Three-day lansoprazole quadruple therapy for Helicobacter pylori-positive duodenal ulcers: a randomized contolled study

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A randomised controlled study comparing the efficacy of once-daily triple therapy with twice-daily triple therapy in the eradication of Helicobacter pylori

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Normal 24-hour ambulatory proximal and distal gastroesophageal reflux parameters in Chinese.

OBJECTIVE: To quantify normal proximal and distal oesophageal acid parameters in healthy Chinese. DESIGN: Observational study. SETTING: University teaching hospital, Hong Kong. SUBJECTS AND METHODS: Twenty healthy adults who were not on medication and were free from gastrointestinal symptoms were recruited by advertisement. Ambulatory oesophageal acid (pH5 minutes, 4/0; and the longest single acid exposure episode, 11.2/3.0 minutes. CONCLUSION: Physiological gastroesophageal reflux occurs in healthy Chinese. These initial data provide a preliminary reference range that could be utilised by laboratories studying Chinese subjects.published_or_final_versio

An evaluation of whole blood testing for Helicobacter pylori infection in the Chinese population

Background: Near patient tests for Helicobacter pylori were developed to assist in the management of dyspepsia patients in general practice. Most studies were performed in western populations. Aim: To evaluate the rapid whole blood test (Flexpack HP) for H. pylori in the Chinese population. Methods: Consecutive dyspeptic patients referred for upper endoscopy were recruited. During upper endoscopy, biopsies were taken from the antrum and corpus for rapid urease test (CLO test) and histological examination. After endoscopy, the whole blood test (FlexPack HP) was performed according to the manufacturer's instruction. Patients then received a 13C-urea breath test. Results of the whole blood test were compared with the gold standard (CLO test, histology and 13C-urea breath test). Results: A total of 294 consecutive patients gave a valid Flexpack HP result for interpretation. The mean age of patients was 47.7 (range 15-85) years. Analysis showed a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 58%, 92%, 91%, 63% and 73% respectively. Conclusion: The FlexPack HP whole blood test showed good specificity but lacked sensitivity. It is not sensitive enough to be used in a general practice setting for the test-and-treat approach in the Chinese population.postprin

Effects of Primary Metronidazole and Clarithromycin Resistance to Helicobacter pylori on Omeprazole, Metronidazole, and Clarithromycin Triple-Therapy Regimen in a Region with High Rates of Metronidazole Resistance

The aim of this study was to investigate the effect of metronidazole resistance (MtzR) and clarithromycin resistance (CIaR) on the eradication rate for omeprazole, clarithromycin, and metronidazole triple-therapy regimen and on the development of posttherapy drug resistance in a region of high rates of MtzR. One hundred ninety-six Helicobacter pylori isolates were recovered from patients with duodenal ulcer, gastric ulcer, or nonulcer dyspepsia during upper endoscopy. The prevalences of MtzR, ClaR, and dual resistance were 37.8%, 13.8%, and 8.7%, respectively. The intention-to-treat eradication rates for metronidazole-susceptible (87.2% vs. 67.6%; P = .001) and clarithromycin-susceptible (86.4% vs. 40.7%; P < .001 ) strains were significantly higher than the rates for resistant strains. Multiple logistic regression analysis implicated younger age (<40 years old), MtzR, ClaR, and the diagnosis of nonulcer dyspepsia as independent factors that predicted treatment failure. The rates of posttreatment MtzR, ClaR, and dual resistance were 88%, 88%, and 75%, respectively. MtxR and ClaR significantly affected the success of eradication therapy. Posttreatment rates of resistance were high and were related to the presence of pretreatment antibiotic resistance.published_or_final_versio

Non-H. pylori, non-NSAID duodenal ulcers: clinical and endoscopic characteristics

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