Prioritization Strategies to reduce the Seismic Risk of the Public and Strategic Buildings

Vona Marco, Anelli Angelo, Mastroberti Monica, Murgante Beniamino and Santa-Cruz Sandra

In the last years, after medium and strong Italian earthquakes a new and virtuous procedure for assessment of seismic capacity of the strategic buildings has been started and carried out. For single building, the best choice to retrofit should be defined based on its specific features and seismic deficiencies. Different methods and alternative approaches exist to define the optimum retrofitting strategy. On contrary, retrofitting strategies on a wide territorial scale (for public and/or strategic buildings) should be based on multiple and diverse aspects. Prioritization of the mitigation strategies with strongly limited budget has become a fundamental topic especially with regard to the limited economic resources and their allocation on national, regional or sub-regional territories. This is a typical political and administrative problem and it is a fundamental topic for decision makers. This issue is certainly of greatest interest for strategic buildings, which must have high performance during and after seismic emergency. In past years, often decision-making and selection of different strategies, they were devoid of rational criteria. Due to both the huge amount of strategic buildings that require interventions and the limited economic availability, it is necessary as a first step to define the priority of interventions on a wide territorial scale. In the present work, the definition of seismic risk management strategies in order to prioritize the retrofitting of the strategic buildings is investigated. The multi-criteria decision-making analysis has been considered and applied to data set of strategic buildings in order to define different propriety ranking able to satisfy different purpose.

Full Text

Study on the Permafrost Prevention Measures and their cooling effects in Cold Regions

Huang Ming-kui and Lv Zhen-hou

Based on previous research of permafrost prevention measures, the semiconductor regulation roadbed structure is introduced. It is able to alleviate the influences of global warming and engineering activities. In this structure, a layer of material is buried in the roadbed to adjust the thermal exchanges between the roadbed and external environment. The material is able to prevent the extra cooling energy from entering the roadbed to form frost heave in cold season and absorb the heat to protect the structure from thawing in warm season. To analyze the cooling effect of the semiconductor roadbed structure and provide the theoretical basis for its design, the regulating mechanism of the semiconductor structure is analyzed in this paper and the temperature fields of the semiconductor and traditional roadbeds are analyzed by finite element method. The results indicated in cold and warm season, the semiconductor structure is able to prevent active permafrost layer from being influenced by engineering activities and external environments and reduce the disease problems of frost heave and thawing.

Full Text

Relationship Analysis between Debris Flow Distribution and its Topographic and Basin Features in Miyun Reservoir Region of China

Su Qiaomei, Zhang Wenjie, Zhao Shangmin and Cheng Weiming

Debris flow is a sudden and significant natural disaster which affects basin evolution processes. Acquiring the relationship between debris flow distribution and its surrounding characteristics is of much importance. Taking Miyun Reservoir Region of China as the study area, this research aims to explore the relationship between debris flow distribution and its corresponding topographic and basin features. Through collection and digitization, the distribution locations of debris flows were acquired from previously published literature. Then, topographic features i.e. relative elevation, slope and aspect were extracted from ASTER GDEM V2 data. Meanwhile, the basin was divided into 316 basins using fitness index and three features of basin i.e. basin area, gully gradient and shape coefficient were chosen and computed. Next, a relationship between debris flow distribution and topographic features and basin features was explored. Finally, the importance of the features to the debris flow distribution was evaluated and a regression model between debris flow distribution and important features was quantitatively built. Research results show: 92.4% debris flows distribute in low mountains with low and middle relief which has elevation of 200 m–1200 m; more than 80% debris flows distribute in gentle (5°–15°), steep (15°–25°) and steeper (25°–35°) slope regions; more debris flows distribute in sunny and semi-sunny slope areas. In term of basin features, debris flows mainly distribute in the basin with area of 20km2–40km2, 40km2–60km2 and 120km2–140km2 and a moderate gully gradient, which is 15%–20%. The study area is divided into sharp basins and ovate basins according to the value of shape coefficient; compared to sharp basins, much more debris flows are distributed in ovate basins; through comparing the importance of the features, the basin area is the most important feature, the next features are slope and basin shape features, the unimportant features are elevation, gully gradient and aspect features. Through evaluation, the root mean square error value is 3.86 between estimated and observed debris flow numbers in the basins. This work not only provides scientific basis for debris flow prediction and prevention in Miyun Reservoir Region but also provides references for other basins and relevant research.

Full Text

Research on Temporal and Spatial Evolution and Driving Factors of Shijiazhuang Urban Heat Island

Duan Xixi, Gao Wei, Du Zitao and Lin Yi

Taking Shijiazhuang as the case study area and Landsat image data of four phases from 2001 to 2015 as the research data source, this paper retrieved the land surface temperature (LST) with the mono-window algorithm and made a spatial distribution map of heat islands. Then it used equal fan method to analyze expanding/subtraction directions, intensity and characteristics of heat islands in long cycles and multi phases and performed a correlation analysis between land surface temperature, NDVI and NDBI. The results showed that the urban heat islands in Shijiazhuang had been growing from 2001 to 2015, experiencing three stages: single-core growth, mild collapse and rapid development; heat islands in Shijiazhuang expanded from a single island in downtown area to three heat islands in downtown area, southern industrial area and Jingxing mining area, with the expansion sped after 2007; land surface temperature was positively correlated with NDBI but negatively correlated with NDVI, their coefficients were 0.846 and -0.540 respectively and NDVI made a more obvious effect on heat island intensity than NDVI.

Full Text

Occurrence Probability and Early Warning of Dendrolimus punctatus Walker Damage based on Remote Sensing

Xu Zhanghua, Liu Jian and Shi Tingting

The Dendrolimus punctatus Walker is the most serious forest defoliator in China. It is meaningful to effectively conduct early warning of Dendrolimus punctatus Walker damage for the forest sustainable development maintenance and economic losses reduction. Taking Fujian Province as the study area, the materials of climate, topography, forest stand, pest source and human environment were collected. Relying on the Quantitative Theory Ⅰ, the pest levels of Dendrolimus punctatus Walker in 2011 were simulated. The occurrence probability of Dendrolimus punctatus Walker damage and its early warning technology was built according to the correspondence of occurrence probability and early warning grades. The results showed that (1) The blue early warning (Degree Ⅳ early warning) of Dendrolimus punctatus Walker damage should be sent out when one of the following states can be met in the regions without occurrence in last year: sunshine hours higher in mid-December last year, low elevation, middle dense forest, sunshine hours within 1359~1580 h last year, average temperature unusual higher in late August last year, average temperature unusual lower in early January this year and sunshine hours unusually lower in mid-December last year. The corresponding probabilities are 12.13%, 10.94%, 10.36%, 10.21%, 10.09%, 10.06% and 10.00% respectively; (2)33 random samples of non-occurrence in 2010 and occurrence in 2011 were used to verify this early warning technology, confirming its reliability.

Full Text

Spatial analysis of IISc campus using remote sensing data and image processing (GIS) technique

Sil Arjun

Land use and land cover analysis are very important aspects of describing the Earth’s features in spatial-temporal manner or alternatively it helps to know the updated information on the earth’s surface for proper planning and management of the natural resources. Variations of land use and land cover reflect the statistics of the region, artificial and natural activities of environment. Remote sensing technology helps providing through an up to date status of spatial data at regular interval of time which is useful for land cover analysis. Geographical Information System (GIS) helps to process the data and also it extracts the necessary information (attributes) available within the images for better utilization of appropriate resources in the field or real life problems. In this study, IISc Campus is taken as a study area by taking 1999-2000 Land sat (TM) satellite imagery data for Bangalore region and analysis shown is based on both the dataset. The classification is done among the different class categories such as built up, vegetation, water bodies etc. through estimation of various vegetation indices (slope based and distance based) and then compared. However, after classification using the maximum likelihood classifier, the variation within one year for built-up shows from 43.79% to 51.70% and vegetation ranges from 40% to 36.55% indicating the more utilization of spaces by reducing vegetation or plants which may affect the ecosystem in the campus.

Full Text