| 1. |
- Wang, Weixing, et al.
(author)
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Pavement crack image acquisition methods and crack extraction algorithms : A review
- 2019
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In: Journal of Traffic and Transportation Engineering (English Edition). - : KEAI PUBLISHING LTD. - 2095-7564. ; 6:6, s. 535-556
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Research review (peer-reviewed)abstract
- The extraction of pavement cracks is always a hard task in image processing. In airport and road construction, cracking is the main factor for pavement damage, which can decrease the quality of pavement and affect transportation seriously. Cracks also exist in other artificial or natural objects, such as buildings, bridges, tunnels, etc. Among all the object images, pavement crack images are the most complex, so the image processing and analysis for them is harder than other crack images. From the early image acquisition based on photography technology to the current 3D laser scanning technology, the pavement crack image acquisition technology is becoming more convenient and efficient, but there are still challenges in the automatic processing and recognition of cracks in images. From the early global thresholding to deep learning algorithms, the research for crack extraction has been developed for about 40 years. There are many methods and algorithms that are satisfactory in pavement crack applications, but there is no standard until today. Therefore, in order to know the developing history and the advanced research, we have collected a number of literature in this research topic for summarizing the research artwork status, and giving a review of the pavement crack image acquisition methods and 2D crack extraction algorithms. Also, for image acquisition methods and pavement crack image segmentation, more detailed comparison and discussions are made.
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| 2. |
- Weinstein, John N., et al.
(author)
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The cancer genome atlas pan-cancer analysis project
- 2013
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:10, s. 1113-1120
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Research review (peer-reviewed)abstract
- The Cancer Genome Atlas (TCGA) Research Network has profiled and analyzed large numbers of human tumors to discover molecular aberrations at the DNA, RNA, protein and epigenetic levels. The resulting rich data provide a major opportunity to develop an integrated picture of commonalities, differences and emergent themes across tumor lineages. The Pan-Cancer initiative compares the first 12 tumor types profiled by TCGA. Analysis of the molecular aberrations and their functional roles across tumor types will teach us how to extend therapies effective in one cancer type to others with a similar genomic profile. © 2013 Nature America, Inc. All rights reserved.
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| 3. |
- Wang, Haidong, et al.
(author)
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Estimates of global, regional, and national incidence, prevalence, and mortality of HIV, 1980-2015 : the Global Burden of Disease Study 2015.
- 2016
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In: The lancet. HIV. - : Elsevier. - 2352-3018. ; 3:8, s. e361-e387
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Journal article (peer-reviewed)abstract
- BACKGROUND: Timely assessment of the burden of HIV/AIDS is essential for policy setting and programme evaluation. In this report from the Global Burden of Disease Study 2015 (GBD 2015), we provide national estimates of levels and trends of HIV/AIDS incidence, prevalence, coverage of antiretroviral therapy (ART), and mortality for 195 countries and territories from 1980 to 2015.METHODS: For countries without high-quality vital registration data, we estimated prevalence and incidence with data from antenatal care clinics and population-based seroprevalence surveys, and with assumptions by age and sex on initial CD4 distribution at infection, CD4 progression rates (probability of progression from higher to lower CD4 cell-count category), on and off antiretroviral therapy (ART) mortality, and mortality from all other causes. Our estimation strategy links the GBD 2015 assessment of all-cause mortality and estimation of incidence and prevalence so that for each draw from the uncertainty distribution all assumptions used in each step are internally consistent. We estimated incidence, prevalence, and death with GBD versions of the Estimation and Projection Package (EPP) and Spectrum software originally developed by the Joint United Nations Programme on HIV/AIDS (UNAIDS). We used an open-source version of EPP and recoded Spectrum for speed, and used updated assumptions from systematic reviews of the literature and GBD demographic data. For countries with high-quality vital registration data, we developed the cohort incidence bias adjustment model to estimate HIV incidence and prevalence largely from the number of deaths caused by HIV recorded in cause-of-death statistics. We corrected these statistics for garbage coding and HIV misclassification.FINDINGS: Global HIV incidence reached its peak in 1997, at 3·3 million new infections (95% uncertainty interval [UI] 3·1-3·4 million). Annual incidence has stayed relatively constant at about 2·6 million per year (range 2·5-2·8 million) since 2005, after a period of fast decline between 1997 and 2005. The number of people living with HIV/AIDS has been steadily increasing and reached 38·8 million (95% UI 37·6-40·4 million) in 2015. At the same time, HIV/AIDS mortality has been declining at a steady pace, from a peak of 1·8 million deaths (95% UI 1·7-1·9 million) in 2005, to 1·2 million deaths (1·1-1·3 million) in 2015. We recorded substantial heterogeneity in the levels and trends of HIV/AIDS across countries. Although many countries have experienced decreases in HIV/AIDS mortality and in annual new infections, other countries have had slowdowns or increases in rates of change in annual new infections.INTERPRETATION: Scale-up of ART and prevention of mother-to-child transmission has been one of the great successes of global health in the past two decades. However, in the past decade, progress in reducing new infections has been slow, development assistance for health devoted to HIV has stagnated, and resources for health in low-income countries have grown slowly. Achievement of the new ambitious goals for HIV enshrined in Sustainable Development Goal 3 and the 90-90-90 UNAIDS targets will be challenging, and will need continued efforts from governments and international agencies in the next 15 years to end AIDS by 2030.
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| 4. |
- Wang, Haidong, et al.
(author)
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Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980-2015 : a systematic analysis for the Global Burden of Disease Study 2015
- 2016
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In: The Lancet. - 0140-6736 .- 1474-547X. ; 388:10053, s. 1459-1544
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Journal article (peer-reviewed)abstract
- BACKGROUND: Improving survival and extending the longevity of life for all populations requires timely, robust evidence on local mortality levels and trends. The Global Burden of Disease 2015 Study (GBD 2015) provides a comprehensive assessment of all-cause and cause-specific mortality for 249 causes in 195 countries and territories from 1980 to 2015. These results informed an in-depth investigation of observed and expected mortality patterns based on sociodemographic measures.METHODS: We estimated all-cause mortality by age, sex, geography, and year using an improved analytical approach originally developed for GBD 2013 and GBD 2010. Improvements included refinements to the estimation of child and adult mortality and corresponding uncertainty, parameter selection for under-5 mortality synthesis by spatiotemporal Gaussian process regression, and sibling history data processing. We also expanded the database of vital registration, survey, and census data to 14 294 geography-year datapoints. For GBD 2015, eight causes, including Ebola virus disease, were added to the previous GBD cause list for mortality. We used six modelling approaches to assess cause-specific mortality, with the Cause of Death Ensemble Model (CODEm) generating estimates for most causes. We used a series of novel analyses to systematically quantify the drivers of trends in mortality across geographies. First, we assessed observed and expected levels and trends of cause-specific mortality as they relate to the Socio-demographic Index (SDI), a summary indicator derived from measures of income per capita, educational attainment, and fertility. Second, we examined factors affecting total mortality patterns through a series of counterfactual scenarios, testing the magnitude by which population growth, population age structures, and epidemiological changes contributed to shifts in mortality. Finally, we attributed changes in life expectancy to changes in cause of death. We documented each step of the GBD 2015 estimation processes, as well as data sources, in accordance with Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER).FINDINGS: Globally, life expectancy from birth increased from 61·7 years (95% uncertainty interval 61·4-61·9) in 1980 to 71·8 years (71·5-72·2) in 2015. Several countries in sub-Saharan Africa had very large gains in life expectancy from 2005 to 2015, rebounding from an era of exceedingly high loss of life due to HIV/AIDS. At the same time, many geographies saw life expectancy stagnate or decline, particularly for men and in countries with rising mortality from war or interpersonal violence. From 2005 to 2015, male life expectancy in Syria dropped by 11·3 years (3·7-17·4), to 62·6 years (56·5-70·2). Total deaths increased by 4·1% (2·6-5·6) from 2005 to 2015, rising to 55·8 million (54·9 million to 56·6 million) in 2015, but age-standardised death rates fell by 17·0% (15·8-18·1) during this time, underscoring changes in population growth and shifts in global age structures. The result was similar for non-communicable diseases (NCDs), with total deaths from these causes increasing by 14·1% (12·6-16·0) to 39·8 million (39·2 million to 40·5 million) in 2015, whereas age-standardised rates decreased by 13·1% (11·9-14·3). Globally, this mortality pattern emerged for several NCDs, including several types of cancer, ischaemic heart disease, cirrhosis, and Alzheimer's disease and other dementias. By contrast, both total deaths and age-standardised death rates due to communicable, maternal, neonatal, and nutritional conditions significantly declined from 2005 to 2015, gains largely attributable to decreases in mortality rates due to HIV/AIDS (42·1%, 39·1-44·6), malaria (43·1%, 34·7-51·8), neonatal preterm birth complications (29·8%, 24·8-34·9), and maternal disorders (29·1%, 19·3-37·1). Progress was slower for several causes, such as lower respiratory infections and nutritional deficiencies, whereas deaths increased for others, including dengue and drug use disorders. Age-standardised death rates due to injuries significantly declined from 2005 to 2015, yet interpersonal violence and war claimed increasingly more lives in some regions, particularly in the Middle East. In 2015, rotaviral enteritis (rotavirus) was the leading cause of under-5 deaths due to diarrhoea (146 000 deaths, 118 000-183 000) and pneumococcal pneumonia was the leading cause of under-5 deaths due to lower respiratory infections (393 000 deaths, 228 000-532 000), although pathogen-specific mortality varied by region. Globally, the effects of population growth, ageing, and changes in age-standardised death rates substantially differed by cause. Our analyses on the expected associations between cause-specific mortality and SDI show the regular shifts in cause of death composition and population age structure with rising SDI. Country patterns of premature mortality (measured as years of life lost [YLLs]) and how they differ from the level expected on the basis of SDI alone revealed distinct but highly heterogeneous patterns by region and country or territory. Ischaemic heart disease, stroke, and diabetes were among the leading causes of YLLs in most regions, but in many cases, intraregional results sharply diverged for ratios of observed and expected YLLs based on SDI. Communicable, maternal, neonatal, and nutritional diseases caused the most YLLs throughout sub-Saharan Africa, with observed YLLs far exceeding expected YLLs for countries in which malaria or HIV/AIDS remained the leading causes of early death.INTERPRETATION: At the global scale, age-specific mortality has steadily improved over the past 35 years; this pattern of general progress continued in the past decade. Progress has been faster in most countries than expected on the basis of development measured by the SDI. Against this background of progress, some countries have seen falls in life expectancy, and age-standardised death rates for some causes are increasing. Despite progress in reducing age-standardised death rates, population growth and ageing mean that the number of deaths from most non-communicable causes are increasing in most countries, putting increased demands on health systems.
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| 5. |
- Wang, Jiabin, et al.
(author)
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The Effect of Bogie Positions on the Aerodynamic Behavior of a High-Speed Train: An IDDES Study
- 2021
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In: Flow, Turbulence and Combustion. - : Springer Science and Business Media LLC. - 1573-1987 .- 1386-6184. ; 107:2, s. 257-282
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Journal article (peer-reviewed)abstract
- In this study, an improved delayed detached-eddy simulation method has been used to investigate the aerodynamic behavior of the CRH2 high-speed trains (HST) with different first and last bogie positions. The results of the numerical simulations have been validated against experimental data obtained from a previous wind tunnel test, a full-scale field test and a reduced-scale moving model test. The results of the flow prediction are used to explore the effects of the bogie positions on the slipstream, wake flow, underbody flow and aerodynamic drag. Compared with the original HST model, the downstream movement of the first bogie, has a great effect on decreasing the slipstream velocity and pressure fluctuation aside the HST, especially around the lower part of the HST. Furthermore, the size of the longitudinal vortex structure and slipstream velocity in the near wake region also decrease significantly by moving the last bogie upstream. Additionally, the movement of the first and last bogies toward the HST center, effectively decreases the drag values of the head and tail car, while a lower effect is observed on the intermediate cars.
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| 6. |
- Zhang, Jie, 1987, et al.
(author)
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A study of the influence of bogie cut outs' angles on the aerodynamic performance of a high-speed train
- 2018
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In: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 175, s. 153-168
-
Journal article (peer-reviewed)abstract
- The aerodynamic drag of a high-speed train can contribute significantly to its energy consumption. Hence, the purpose of this paper is to find out a new compound mode of bogie cut outs to achieve drag reduction for a Chinese high-speed train. In this paper, a Detached Eddy Simulation method based on the Realizable k-ε turbulence model was used to investigate the underbody flow features of high-speed trains with different compound modes in the angles of bogie cut outs at Re = 1.85 × 10 6 . The time-averaged aerodynamic drag was compared with experimental data from wind tunnel tests. The results show that the DES simulations present high accuracy in predicting this kind of flow underneath the train body, and those numerical results closely agree with the experimental data. The variations of bogie cut outs' angles only cause the changes of flow structures around the bogies and in the wake. As a result, obtain different aerodynamic drag forces. Most of drag of the train is experienced by the streamlined head and all bogie regions. A new compound mode of bogie cut outs is proposed in the present paper, achieving 2.92% drag reduction for a three-car model.
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| 7. |
- Dong, Tianyun, 1990, et al.
(author)
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Numerical investigation of a high-speed train underbody flows: Studying flow structures through large-eddy simulation and assessment of steady and unsteady Reynolds-averaged Navier-Stokes and improved delayed detached eddy simulation performance
- 2022
-
In: Physics of Fluids. - : AIP Publishing. - 1070-6631 .- 1089-7666. ; 34:1
-
Journal article (peer-reviewed)abstract
- The underbody flow of a truncated, 1:10 scaled, CRH380A model is investigated at Re = 2.78 × 105 in this paper. The large-eddy simulation (LES) is used to study the main features of the development of the underbody flow under the snowplow, in the bogie/cavity region and after the cavity (equip-cabin region). A grid independence study and a validation against experimental data have been done prior to the investigation. The snowplow region is dominated by a pair of separated counter-rotating vortices, which further affects the downstream flow. A strong shear layer is observed in the cavity region, and the turbulent flow is intensively triggered by the shear instability and the complex bogie components within the cavity region. The equip-cabin region allows the turbulent flow to develop without any disturbance, decreasing the turbulence intensity. Moreover, the steady and unsteady Reynolds-averaged Navier-Stokes (RANS, URANS) model and the improved delayed detached eddy simulation (IDDES) are used to compute the same flow, and to compare the results to LES. The solution differences, in terms of aerodynamic forces and the underbody flow state, are analyzed. Specifically, the minimum velocity discrepancy, at line2, between RANS (URANS) and LES is 14.4%, while IDDES is 3.6%. The solution accuracy vs the computational cost is also reported.
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| 8. |
- Dong, Tianyun, et al.
(author)
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The effect of ground clearance on the aerodynamics of a generic high-speed train
- 2020
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In: Journal of Fluids and Structures. - : Elsevier BV. - 1095-8622 .- 0889-9746. ; 95
-
Journal article (peer-reviewed)abstract
- The influence of ground clearance on the flow around a simplified high-speed train is investigated in this paper. Four clearance heights are studied using IDDES. After a grid independence study, the results of the simulations are validated against experimental data present in the literature. It is found that the drag decreases when reducing the clearance gap from the baseline height to a possibly critical height, while drag remains constant when the clearance is lower than this critical height. The negative lift (downforce) increases with the decreasing of the clearance gap. The flow is particularly influenced by the gap height at the underbody and wake regions, where a lower underbody velocity and a higher wake velocity are observed with lower clearance down to case h2. Therefore, the different topologies of the wake are presented and described. Particular attention is paid to the description of the wake flow and to the position and the formation of the flow mixing region. Specifically, with decreasing clearance, the mix of the tail downwash and underbody flows happen earlier, and the core of the counter-rotating vortices in the wake tends to develop with an increasing height trend. Overall, aerodynamic performance and flow structure descriptions show positive and negative effects when decreasing gap clearances, which should be taken into account for new design strategies.
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| 9. |
- Dong, Tianyun, et al.
(author)
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The effect of reducing the underbody clearance on the aerodynamics of a high-speed train
- 2020
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In: Journal of Wind Engineering and Industrial Aerodynamics. - : Elsevier BV. - 0167-6105. ; 204
-
Journal article (peer-reviewed)abstract
- The effect of lowering the ground clearance, on train aerodynamics is investigated using IDDES. The high speed train geometry with its full underbody complexity is used in the investigation. The clearance is reduced by installing extra panels on the track. The numerical results are verified and validated by a grid independence study and experimental data. This work shows that, when lowered the clearance, the underbody velocity at the head car decreases, while the underbody velocity at the middle and tail car increases. The reduced clearance barely affects the time-averaged slipstream at 3 m away from the center of track. However, at a closer distance to the train body, the difference in velocity is observed to reach up to 50% between the two clearance configurations and the clearance has an opposite effect on the trackside and platform slipstream. Based on the analysis of ensemble-averaged slipstream, lowering the underbody clearance, the characteristic air speed at the trackside and platform height increases by 2.0% and 6.7%, respectively. The total drag is almost unaffected by the clearance, but the changed distribution of the drag indicates a larger drag depends on the bogie structure if longer grouped train is used. The total lift decreases 25.9% after the clearance is reduced. Specifically, 4.1% of the negative lift is increased at the head car, while the positive lift decreases 92.7% and 1.8% for the middle and tail car, respectively. Overall it is shown that reducing the underbody clearance barely affect the slipstream at standard positions, but affects more aerodynamic loads of the train.
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| 10. |
- Griswold, Max G., et al.
(author)
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Alcohol use and burden for 195 countries and territories, 1990-2016 : a systematic analysis for the Global Burden of Disease Study 2016
- 2018
-
In: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 392:10152, s. 1015-1035
-
Journal article (peer-reviewed)abstract
- Background: Alcohol use is a leading risk factor for death and disability, but its overall association with health remains complex given the possible protective effects of moderate alcohol consumption on some conditions. With our comprehensive approach to health accounting within the Global Burden of Diseases, Injuries, and Risk Factors Study 2016, we generated improved estimates of alcohol use and alcohol-attributable deaths and disability-adjusted life-years (DALYs) for 195 locations from 1990 to 2016, for both sexes and for 5-year age groups between the ages of 15 years and 95 years and older.Methods: Using 694 data sources of individual and population-level alcohol consumption, along with 592 prospective and retrospective studies on the risk of alcohol use, we produced estimates of the prevalence of current drinking, abstention, the distribution of alcohol consumption among current drinkers in standard drinks daily (defined as 10 g of pure ethyl alcohol), and alcohol-attributable deaths and DALYs. We made several methodological improvements compared with previous estimates: first, we adjusted alcohol sales estimates to take into account tourist and unrecorded consumption; second, we did a new meta-analysis of relative risks for 23 health outcomes associated with alcohol use; and third, we developed a new method to quantify the level of alcohol consumption that minimises the overall risk to individual health.Findings: Globally, alcohol use was the seventh leading risk factor for both deaths and DALYs in 2016, accounting for 2.2% (95% uncertainty interval [UI] 1.5-3.0) of age-standardised female deaths and 6.8% (5.8-8.0) of age-standardised male deaths. Among the population aged 15-49 years, alcohol use was the leading risk factor globally in 2016, with 3.8% (95% UI 3.2-4-3) of female deaths and 12.2% (10.8-13-6) of male deaths attributable to alcohol use. For the population aged 15-49 years, female attributable DALYs were 2.3% (95% UI 2.0-2.6) and male attributable DALYs were 8.9% (7.8-9.9). The three leading causes of attributable deaths in this age group were tuberculosis (1.4% [95% UI 1. 0-1. 7] of total deaths), road injuries (1.2% [0.7-1.9]), and self-harm (1.1% [0.6-1.5]). For populations aged 50 years and older, cancers accounted for a large proportion of total alcohol-attributable deaths in 2016, constituting 27.1% (95% UI 21.2-33.3) of total alcohol-attributable female deaths and 18.9% (15.3-22.6) of male deaths. The level of alcohol consumption that minimised harm across health outcomes was zero (95% UI 0.0-0.8) standard drinks per week.Interpretation: Alcohol use is a leading risk factor for global disease burden and causes substantial health loss. We found that the risk of all-cause mortality, and of cancers specifically, rises with increasing levels of consumption, and the level of consumption that minimises health loss is zero. These results suggest that alcohol control policies might need to be revised worldwide, refocusing on efforts to lower overall population-level consumption.
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