On verifying timed hyperproperties

We study the satisfiability and model-checking problems for timed hyperproperties specified with HyperMTL, a timed extension of HyperLTL. Depending on whether interleaving of events in different traces is allowed, two possible semantics can be defined for timed hyperproperties: asynchronous and synchronous. While the satisfiability problem can be decided similarly to HyperLTL regardless of the choice of semantics, we show that the model-checking problem, unless the specification is alternation-free, is undecidable even when very restricted timing constraints are allowed. On the positive side, we show that model checking HyperMTL with quantifier alternations is possible under certain conditions in the synchronous semantics, or when there is a fixed bound on the length of the time domain.EP/K026399/1 and EP/P020011/

Timed hyperproperties

We study the satisfiability and model-checking problems for timed hyperproperties specified with HyperMITL, a timed extension of HyperLTL. While the satisfiability problem can be solved similarly as for HyperLTL, we show that the model-checking problem for HyperMITL, unless the specification is alternation-free, is undecidable even when very restricted timing constraints are allowed. On the positive side, we show that model checking HyperMITL with quantifier alternations is possible under certain semantic restrictions. As an intermediate tool, we give an ‘asynchronous’ interpretation of Wilke's monadic logic of relative distance (L ) and show that it characterises timed languages recognised by timed automata with silent transitions. d

The reliability-based stochastic transit assignment problem with elastic demand

This paper examines the reliability-based stochastic transit assignment problem with elastic demand. A Variational Inequality (VI) model for this problem is developed. The VI model considers capacity, waiting time and in-vehicle travel time as stochastic variables, and includes Spiess and Florian’s (1989) and de Cea and Fernández’s (1993) models as special cases. A reliability-based stochastic user equilibrium condition is defined to capture the route choice behavior of passengers. To illustrate the properties of the VI model, numerical studies were conducted on de Cea and Fernández’s (1993) network. The studies also show that Spiess and Florian’s and de Cea and Fernández’s models can overestimate the system performance substantially.postprin

Simulation of the control method for the adaptive front lighting system

Author name used in this publication: K. W. E. ChengAuthor name used in this publication: S. L. HoVersion of RecordPublishe

Effect of duration of ischaemia on infarct volume in the rat

published_or_final_versio

Development of electric vehicle with advanced lighting system and all electric drive

Author name used in this publication: K. W. E. ChengAuthor name used in this publication: S. L. HoVersion of RecordPublishe

Frozen-thawed embryo transfer cycles

Objective: To review the outcomes of frozen-thawed embryo transfer cycles. Design: Retrospective review. Setting: Tertiary assisted reproduction centre, Hong Kong. Patients: Subfertile patients undergoing frozen-thawed embryo transfer between July 2005 and December 2007. Main outcome measures: Clinical and ongoing pregnancy rates. Results: A total of 983 frozen-thawed embryo transfer cycles performed during the study period were reviewed. The clinical pregnancy and ongoing pregnancy rates were 35% and 30%, respectively. Factors associated with successful outcome included younger maternal age (≤35 years) and 4 or more blastomeres at replacement, but not the method of insemination, the cause of subfertility, or the type of frozen-thawed embryo transfer cycle. The overall multiple pregnancy rate was 18%. For cycles with a single embryo replaced, embryos having 4-cell or higher stages at replacement gave an ongoing pregnancy rate of 25%, whereas those with less than 4 cells had a significantly lower ongoing pregnancy rate of 5% only. Blastomere lysis after thawing significantly reduced the clinical pregnancy and ongoing pregnancy rates of cycles with one embryo replaced. Conclusions Clinical pregnancy and ongoing pregnancy rates of frozen-thawed embryo transfer cycles were 35% and 30%, respectively. Higher pregnancy rates were associated with younger maternal age (≤35 years), blastomere numbers of 4 or more, and no blastomere lysis after thawing.published_or_final_versio

Pelvo-ureteric junction obstruction in the lower pole moiety of a duplex kidney with an associated intraparenchymal abscess: a case report

<p>Abstract</p> <p>Introduction</p> <p>Pelvo-ureteric junction obstruction and duplex kidney are common radiological findings. However, pelvo-ureteric junction obstruction in a duplex kidney is a rare finding. We present the case of a patient who presented with septic complications secondary to this combination.</p> <p>Case presentation</p> <p>An adult woman presented with urinary sepsis, and her initial investigation with ultrasound revealed hydronephrosis of the lower moiety of a duplex kidney. Further investigations with computed tomography and magnetic resonance imaging showed an associated intrarenal abscess and a pelvo-ureteric junction obstruction of the lower moiety of a duplex kidney.</p> <p>Conclusion</p> <p>This patient had a rare and unreported complication of an unusual congenital urological abnormality. This case report highlights the role of multiple imaging modalities in correct diagnosis for clinical management.</p

Prevalence of albuminuria and cardiovascular risk profile in a referred cohort of patients with type 2 diabetes: An Asian perspective

Background: Microalbuminuria (MA) is a risk marker for diabetic nephropathy and cardiovascular (CV) disease (CVD) in patients with diabetes. This study aimed to describe the prevalence of albuminuria, CV risk factors, and treatments for renal and CV protection in an Asian population with type 2 diabetes. Methods: This cross-sectional study conducted in eight Asian countries enrolled normotensive/hypertensive adults with type 2 diabetes without known proteinuria and/or non-diabetic kidney disease. Exclusion criteria were type 1 diabetes, menstruation, pregnancy, and acute fever. A single random urinary albumin/creatinine test was carried out in all patients. Results: Of 8,561 patients, 14% had diabetic retinopathy, and 17% and 21% had history of CV disease and smoking, respectively. Normoalbuminuria was seen in 44%, MA in 44%, and macroalbuminuria in 12%. Target glycosylated hemoglobin (HbA1c) (<7%) was reached in only 37% of 3,834 patients with available values. Diabetes was managed by diet alone in 6%, while others received oral hypoglycemic drugs and/or insulin. In total, 75% did not reach target blood pressure (BP) of ≤130/80 mm Hg. Antihypertensive drugs were prescribed to 52%, with the number of drugs increasing as the level of systolic BP increased. Drugs blocking the renin-angiotensin system were most commonly prescribed, followed by calcium channel blockers. Lipid-lowering drugs and anticoagulant/antiplatelet agents were used in about 30% and 25% of patients, respectively. Conclusions: Asian patients with type 2 diabetes had a high prevalence of MA and reduced kidney function. Furthermore, BP and HbA1c control was only achieved in a minority of patients. Aggressive risk management by administration of reno- and cardioprotective treatments is urgently needed. © 2008 Mary Ann Liebert, Inc.published_or_final_versio

Spatially-resolved electronic and vibronic properties of single diamondoid molecules

Diamondoids are a unique form of carbon nanostructure best described as hydrogen-terminated diamond molecules. Their diamond-cage structures and tetrahedral sp3 hybrid bonding create new possibilities for tuning electronic band gaps, optical properties, thermal transport, and mechanical strength at the nanoscale. The recently-discovered higher diamondoids (each containing more than three diamond cells) have thus generated much excitement in regards to their potential versatility as nanoscale devices. Despite this excitement, however, very little is known about the properties of isolated diamondoids on metal surfaces, a very relevant system for molecular electronics. Here we report the first molecular scale study of individual tetramantane diamondoids on Au(111) using scanning tunneling microscopy and spectroscopy. We find that both the diamondoid electronic structure and electron-vibrational coupling exhibit unique spatial distributions characterized by pronounced line nodes across the molecular surfaces. Ab-initio pseudopotential density functional calculations reveal that the observed dominant electronic and vibronic properties of diamondoids are determined by surface hydrogen terminations, a feature having important implications for designing diamondoid-based molecular devices.Comment: 16 pages, 4 figures. to appear in Nature Material