Airborne near-real-time monitoring of assembly and parking areas in case of large-scale public events and natural disasters     

Hannes Römer  Jens Kersten  Ralph Kiefl  Stefan Plattner  Alexander Mager  Stefan Voigt 《International journal of geographical information science》2014,28(4):682-699

A critical requirement for an effective and coordinated response by public entities tasked with management, security, and relief during large-scale public events or natural disasters is the availability of current situational information. However, today there is a lack of comprehensive operational systems allowing a near-real-time (NRT) collection, visualization, and provision of situational information for larger areas. In this study a methodological framework is proposed, which allows an NRT extraction and visualization of situational information based on aerial image acquisition. The framework combines digital image analysis using a generic supervised information extraction approach based on statistical modeling with a downstream web-based visualization component realized through an automatic update of web services. Even though being applicable for different scenarios, the workflow will be demonstrated for the specific use-case of a NRT monitoring of open spaces including assembly and parking areas. Compared to other approaches, image analysis results indicate a high robustness and a low demand for computational power sources (7 seconds per image). Due to a high degree of automation, the proposed workflow contributes to a NRT ‘end-to-end’ monitoring system, which was developed within the VABENE (German acronym for ‘traffic management under large-scale public events and disaster conditions’) project covering all parts from the acquisition of raw aerial imagery to the dissemination of information products to end-users.  相似文献   

Impact of Hydropower Regulation on River Water Composition in Northern Sweden     

Dmytro Siergieiev  Anders Widerlund  Angela Lundberg  Lisbeth Almqvist  Magali Collomp  Johan Ingri  Björn Öhlander 《Aquatic Geochemistry》2014,20(1):59-80

Using hydrogeochemical analysis of two large boreal rivers (pristine Kalix and hydropower regulated Lule) discharging into the Gulf of Bothnia, the major impacts of regulation on water discharge, element transport and their seasonal redistribution have been assessed. The pre-regulation hydrogeochemical features were assumed to be similar for the two rivers. For the Lule River, the average maximum runoff was almost halved, while the average minimum was tripled as a result of the regulation. The fraction of winter transport of total organic carbon (TOC), Fe, Si, suspended Mn and P in the Lule River was, according to a conservative estimate, two to three times higher than in the pristine river. Longer residence time in the Lule River delayed arrival of the suspended Mn peak and dissolved Si decline to the river mouth. During summer, the suspended C/N ratio in the regulated river was 10–20 compared to <10 for the pristine, suggesting presence of predominantly old organic material. This was supported by a virtually constant suspended P/Fe ratio throughout the year in the Lule River, indicating low abundance of phytoplankton. TOC varied irregularly in the Lule River suggesting temporal disconnection between the river and the upper riparian zone. The disappearance of the spring flow maximum, a shift of element transport from spring to winter and supply of mainly old organic material during the vegetation growth season may have a pronounced impact on the ecosystem of the Gulf of Bothnia and the river itself.  相似文献   

Investigation of surface and subsurface displacements due to multiple tunnels excavation in urban area     

Alireza Talebinejad  Hamid Chakeri  Mahdi Moosavi  Yılmaz Özçelik  Bahtiyar Ünver  Mehmet Ali Hindistan 《Arabian Journal of Geosciences》2014,7(9):3913-3923

Underground structures are currently widely used and are built as urbanism develops. The interactions between perpendicularly crossing and parallel tunnels in the Tehran region are investigated by using a full three-dimensional (3D) finite difference analysis with elastic-plastic material models. Special attention is paid to the effect of subsequent tunneling on the support system, i.e., the shotcrete lining and rock bolts of the existing tunnel. Eventually, as the tunnels are excavated at certain levels, the interaction between the tunnels will certainly have a significant influence on both stress distribution and consequently deformations. Since multilayer tunneling is a three-dimensional phenomenon in nature, 3D numerical solutions must be utilized for analyzing effect of perpendicularly crossing tunnels at various levels. As Tohid twin tunnels and Line 7 pass beneath the Line 4 metro tunnel, changes in stress distribution, deformations, and surface settlements are studied for various conditions and the results are presented in this paper. Consequently, it is shown that there is a significant interaction between tunnels that necessitate certain preventive measures to maintain a stable tunneling operation.  相似文献   

ISRM Suggested Method for the Needle Penetration Test   总被引：1，自引：0，他引：1  

Resat Ulusay  Ömer Aydan  Zeynal A. Erguler  Dominique J. M. Ngan-Tillard  Takafumi Seiki  Wim Verwaal  Yasuhito Sasaki  Akira Sato 《Rock Mechanics and Rock Engineering》2014,47(3):1073-1085

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A New Rock Mass Quality Rating System: Rock Mass Quality Rating (RMQR) and Its Application to the Estimation of Geomechanical Characteristics of Rock Masses   总被引：1，自引：0，他引：1  

Ömer Aydan  Reşat Ulusay  Naohiko Tokashiki 《Rock Mechanics and Rock Engineering》2014,47(4):1255-1276

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Crack Initiation and Crack Propagation in Heterogeneous Sulfate-Rich Clay Rocks   总被引：2，自引：1，他引：1  

Florian Amann  Ömer Ündül  Peter K. Kaiser 《Rock Mechanics and Rock Engineering》2014,47(5):1849-1865

Brittle fracture processes were hypothesized by several researches to cause a damage zone around an underground excavation in sulfate-rich clay rock when the stress exceeds the crack initiation threshold, and may promote swelling by crystal growth in newly formed fractures. In this study, laboratory experiments such as unconfined and confined compression tests with acoustic emission monitoring, and microstructural and mineralogical analyses are used to explain brittle fracture processes in sulfate-rich clay rock from the Gipskeuper formation in Switzerland. This rock type typically shows a heterogeneous rock fabric consisting of distinct clayey layers and stiff heterogeneities such as anhydrite layers, veins or nodules. The study showed that at low deviatoric stress, the failure behavior is dominated by the strength of the clayey matrix where microcracks are initiated. With increasing deviatoric stress or strain, growing microcracks eventually are arrested at anhydrite veins, and cracks develop either aligned with the interface between clayey layers and anhydrite veins, or penetrate anhydrite veins. These cracks often link micro-fractured regions in the specimen. This study also suggest that fracture localization in sulfate-rich clay rocks, which typically show a heterogeneous rock fabric, does not take place in the pre-peak range and renders unstable crack propagation less likely. Sulfate-rich clay rocks typically contain anhydrite veins at various scales. At the scale of a tunnel, anhydrite layers or veins may arrest growing fractures and prevent the disintegration of the rock mass. The rock mass may be damaged when the threshold stress for microcrack initiation is exceeded, thus promoting swelling by crystal growth in extension fractures, but the self-supporting capacity of the rock mass may be maintained rendering the possibility for rapidly propagating instability less likely.  相似文献   

Is area affected by flood or stagnant water independently associated with poorer health outcomes in urban slums of Dhaka and adjacent rural areas?     

M. M. H. Khan  Oliver Gruebner  Alexander Krämer 《Natural Hazards》2014,70(1):549-565

This study investigated the association of flood/stagnant water (FSW) with various health outcomes among respondents living in urban slums of Dhaka and adjacent rural areas. We also assessed the differences of individual-, household- and area-level characteristics between the FSW-affected and non-affected areas. Bangladesh as a whole and slums in the megacity of Dhaka in particular are severely affected by the FSW. Data were collected from 3,207 subjects (aged 10+ years) through baseline surveys conducted in March 2008 and 2009. Twelve big slums in Dhaka and three adjacent villages were selected as study areas. Face-to-face interviews using a multidimensional pre-tested questionnaire were conducted by the trained university graduates. We performed various types of analyses ranging from the simple frequency analysis to the multivariable-adjusted logistic regression modelling. Our empirical findings suggest that slums were more affected by the FSW as compared to the rural areas. People living in the FSW-affected areas were more vulnerable in terms of individual-, household- and area-level characteristics than non-affected people. Age was also significantly associated with various health outcomes. According to multivariable analyses controlled for various factors, the FSW-affected people reported significantly higher likelihoods of health symptoms (namely fever, cold/cough, weakness), communicable diseases (namely diarrhoea and gastric disease) and poor mental well-being as compared to the non-affected people. Only the burden of non-communicable diseases was lower in the FSW-affected areas than the non-affected areas. Our findings lead us to conclude that the FSW-affected area is an independent risk factor for various physical and mental health problems. Urban slums are more affected than rural areas by the FSW. Therefore, we underscore the necessities of well-designed and comprehensive public health interventions focusing on individual, community and higher levels of interventions to reduce the FSW-related health and other consequences among the people living in the FSW-affected areas and urban slums in the rapidly growing city of Dhaka, Bangladesh.  相似文献   

Pushover and nonlinear time history analysis evaluation of a RC building collapsed during the Van (Turkey) earthquake on October 23, 2011     

Özlem Çavdar  Alemdar Bayraktar 《Natural Hazards》2014,70(1):657-673

The nonlinear seismic behavior of a collapsed reinforced concrete (RC) residential building in the city of Van in Turkey is investigated by the static pushover and nonlinear time history analyses. The selected RC structure was designed according to the 1975 version of Turkish Earthquake Code (TEC-1975). The building had experienced heavy damage, and it was demolished in the Van earthquake on October 23, 2011. The 2007 version of Turkish Earthquake Code (TEC-2007) is considered for the assessing seismic performance evaluation of the selected RC building. The RC structure presents collapse performance level under the earthquake loads. Besides, the analytical solutions show that different performance levels for the sections are obtained from the pushover and nonlinear time history methods.  相似文献   

Stable (H,O, C) and noble-gas (He and Ar) isotopic compositions from calcite and fluorite in the Speewah Dome,Kimberley Region,Western Australia: implications for the conditions of crystallization and evidence for the influence of crustal-mantle fluid mixing     

Gy Czuppon  R. R. Ramsay  I. Özgenc  A. Demény  L. G. Gwalani  K. Rogers  A. Eves  L. Papp  L. Palcsu  M. Berkesi  P. J. Downes 《Mineralogy and Petrology》2014,108(6):759-775

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The 150d Modulation of the X-ray Emission of CYG X-1     

S. Özdemir  O. Demircan 《Astrophysics and Space Science》2001,278(3):319-325

The X-ray observations of Cyg X-1, covering a period of 3.8 years, by the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) were analysed to search for long periodicities. The periodicities in the original data were seen to be distorted by the high/soft state and the failed state counts of the system, and thus the power spectra showed two unrealistic peaks at 1608and 406 days. The ∼ 300 day modulation reported previously(e.g. Priedhorsky et al. 1983) is not confirmed by the present ASM data. Truncation of the high counts above 30 cnts/s partly eliminates the distortion and reveals the true period of 150^d in the power spectra. It is interesting that the high/soft state (HS) and the failed state transitions (FST) always occur on the maximum phase of the150^d cycle. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献