VIRTUE : integrating CFD ship design

Novel ship concepts, increasing size and speed, and strong competition in the global maritime market require that a ship's hydrodynamic performance be studied at the highest level of sophistication. All hydrodynamic aspects need to be considered so as to optimize trade-offs between resistance, propulsion (and cavitation), seakeeping or manoeuvring. VIRTUE takes a holistic approach to hydrodynamic design and focuses on integrating advanced CFD tools in a software platform that can control and launch multi-objective hydrodynamic design projects. In this paper current practice, future requirements and a potential software integration platform are presented. The necessity of parametric modelling as a means of effectively generating and efficiently varying geometry, and the added-value of advanced visualization, is discussed. An illustrating example is given as a test case, a container carrier investigation, and the requirements and a proposed architecture for the platform are outlined

Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

Ristola M. on työryhmien DAD Study Grp ; Royal Free Hosp Clin Cohort ; INSIGHT Study Grp ; SMART Study Grp ; ESPRIT Study Grp jäsen.Background Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice. Methods and Findings A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with >= 3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7-6.7; median follow-up 6.1 y, range 0.3-9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was -2 (interquartile range -4 to 2). There was a 1: 393 chance of developing CKD in the next 5 y in the low risk group (risk score = 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166-3,367); NNTH was 202 (95% CI 159-278) and 21 (95% CI 19-23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506-1462), 88 (95% CI 69-121), and 9 (95% CI 8-10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor. The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3-12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6-8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria. Conclusions Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.Peer reviewe

Hologrammsynthese und 3D-Analyse in der digitalen Holografie

Die holografische 3D-Visualisierung ist eine gro"se Herausforderung in der aktuellen Forschung. Neben der Entwicklung eines entsprechenden Ausgabeger"ats ist die schnelle Hologrammsynthese eine Voraussetzung f"ur ein interaktives holografisches Ausgabesystem. In dieser Arbeit wird ein Algorithmus f"ur die effiziente Erzeugung digitaler Hologramme mit PC Grafikhardware vorgestellt. Des Weiteren werden 3D-Rekonstruktionsverfahren von Hologrammen untersucht, die mit einer CCD-Kamera aufgenommen werden k"onnen

Fast Hologram Synthesis for 3D Geometry Models Using Graphics Hardware

The holographic visualization of three-dimensional object geometry still represents a major challenge in computational holography research. Besides the development of suitable holographic display devices, the fast calculation of the hologram’s interference pattern for complex-shaped three-dimensional objects is an important pre-requisite of any interactive holographic display system. We present a fast method for rendering full-parallax holograms using a standard PC with a consumer-market graphics card. To calculate the hologram of a 3D object, scaled and translated versions of the interference pattern of simple primitives, e.g. point sources, are superimposed. The hologram is built up completely on-board the graphics card. To avoid numerical inaccuracies due to limited frame-buffer resolution, we use a hierarchical approach. Using an NVidia Geforce4 graphics card, the proposed algorithm takes 1.0 second to calculate the 512x512-pixel hologram of 1024 primitives

Fast Hologram Synthesis for 3D Geometry Models using Graphics Hardware

The holographic visualization of three-dimensional object geometry still represents a major challenge in computational holography research. Besides the development of suitable holographic display devices, the fast calculation of the hologram's interference pattern for complex-shaped three-dimensional objects is an important pre-requisite of any interactive holographic display system. We present a fast method for rendering full-parallax holograms using a standard PC with a consumer-market graphics card. To calculate the hologram of a 3D object, scaled and translated versions of the interference pattern of simple primitives, e.g. point sources, are superimposed. The hologram is built up completely on-board the graphics card. To avoid numerical inaccuracies due to limited frame-buffer resolution, we use a hierarchical approach. Using an NVidia Geforce4 graphics card, the proposed algorithm takes 1.0 second to calculate the 512x512-pixel hologram of 1024 primitives