排序方式： 共有73条查询结果，搜索用时 62 毫秒
11.
Theoretical and Applied Climatology - Precipitation as the main process that brings evaporated water from the oceans to the land’s surface is a critical role player in Lake Urmia basin... 相似文献
12.
Seyedsina Yousefianmoghadam Mingming Song Mohammad Ebrahim Mohammadi Brittany Packard Andreas Stavridis Babak Moaveni Richard L. Wood 《地震工程与结构动力学》2020,49(9):924-945
This paper discusses the dynamic tests of a two-story infilled reinforced concrete (RC) frame building using an eccentric-mass shaker. The building, located in El Centro, CA, was substantially damaged prior to the tests due to the seismic activity in the area. During the testing sequence, five infill walls were removed to introduce additional damage states and to investigate the changes in the dynamic properties and the nonlinear response of the building to the induced excitations. The accelerations and displacements of the structure under the forced and ambient vibrations were recorded through an array of sensors, while lidar scans were obtained to document the damage. The test data provide insight into the nonlinear response of an actual building and the change of its resonant frequencies and operational shapes due to varying damage levels and changes of the excitation amplitude, frequency, and orientation. 相似文献
13.
Amir Semnani Liang Wang Mehdi Ostadhassan Majid Nabi-Bidhendi Babak Nadjar Araabi 《Geophysical Prospecting》2019,67(7):1701-1719
Matching pursuit belongs to the category of spectral decomposition approaches that use a pre-defined discrete wavelet dictionary in order to decompose a signal adaptively. Although disengaged from windowing issues, matching point demands high computational costs as extraction of all local structure of signal requires a large size dictionary. Thus in order to find the best match wavelet, it is required to search the whole space. To reduce the computational cost of greedy matching pursuit, two artificial intelligence methods, (1) quantum inspired evolutionary algorithm and (2) particle swarm optimization, are introduced for two successive steps: (a) initial estimation and (b) optimization of wavelet parameters. We call this algorithm quantum swarm evolutionary matching pursuit. Quantum swarm evolutionary matching pursuit starts with a small colony of population at which each individual, is potentially a transformed form of a time-frequency atom. To attain maximum pursuit of the potential candidate wavelets with the residual, the colony members are adjusted in an evolutionary way. In addition, the quantum computing concepts such as quantum bit, quantum gate, and superposition of states are introduced into the method. The algorithm parameters such as social and cognitive learning factors, population size and global migration period are optimized using seismic signals. In applying matching pursuit to geophysical data, typically complex trace attributes are used for initial estimation of wavelet parameters, however, in this study it was shown that using complex trace attributes are sensitive to noisy data and would have lower rate of convergence. The algorithm performance over noisy signals, using non-orthogonal dictionaries are investigated and compared with other methods such as orthogonal matching pursuit. The results illustrate that quantum swarm evolutionary matching pursuit has the least sensitivity to noise and higher rate of convergence. Finally, the algorithm is applied to both modelled seismograms and real data for detection of low frequency anomalies to validate the findings. 相似文献
14.
Sadeghi Babak Taghavi Farahnaz Akmal Amir Abbas Shayegani 《Geomagnetism and Aeronomy》2019,59(6):770-781
Geomagnetism and Aeronomy - In this study, a hypothesis is proposed about the possible effect of Geomagnetic field (GMF) on the charge structure of a thundercloud based on Lorentz force equation... 相似文献
15.
Iran is one of the most seismically active countries of the world located on the Alpine-Himalayan earthquake belt. More than
180,000 people were killed due to earthquakes in Iran during the last five decades. Considering the fact that most Iranians
live in masonry and non-engineered houses, having a comprehensive program for decreasing the vulnerability of society holds
considerable importance. For this reason, loss estimation should be done before an earthquake strikes to prepare proper information
for designing and selection of emergency plans and the retrofitting strategies prior to occurrence of earthquake. The loss
estimation process consists of two principal steps of hazard analysis and vulnerability assessment. After identifying the
earthquake hazard, the first step is to evaluate the vulnerability of residential buildings and lifelines and also the social
and economic impacts of the earthquake scenarios. Among these, residential buildings have specific importance, because their
destruction will disturb the daily life and result in casualties. Consequently, the vulnerability assessment of the buildings
in Iran is important to identify the weak points in the built environment structure. The aim of this research is to prepare
vulnerability curves for the residential buildings of Iran to provide a proper base for estimating probable damage features
by future earthquakes. The estimation may contribute fundamentally for better seismic performance of Iranian societies. After
a brief review of the vulnerability assessment methods in Iran and other countries, through the use of the European Macroseismic
method, a model for evaluating the vulnerability of the Iranian buildings is proposed. This method allows the vulnerability
assessment for numerous sets of buildings by defining the vulnerability curves for each building type based on the damage
observations of previous earthquakes. For defining the vulnerability curves, a building typology classification is presented
in this article, which is representative of Iranian building characteristics. The hazard is described in terms of the macroseismic
intensity and the EMS-98 damage grades have been considered for classifying the physical damage to the buildings. The calculated
vulnerability indexes and vulnerability curves show that for engineered houses there is not any notable difference between
the vulnerability of Iranian and Risk-UE building types. For the non-engineered houses, the vulnerability index of brick and
steel structures is less than the corresponding values of the other unreinforced masonry buildings of Iran. The vulnerability
index of unreinforced and masonry buildings of Iran are larger than the values of the similar types in Risk-UE and so the
Iranian buildings are more vulnerable in this regard. 相似文献
16.
Evaluation of public participation in reconstruction of Bam,Iran, after the 2003 earthquake 总被引：1，自引：1，他引：0
In the midst of the ever-increasing natural and human-induced disasters, where many of the preparedness and mitigation measures
show inefficiencies, there is narrow margin for decision-makers to make mistakes by misallocating budgets, designing infeasible
reconstruction plans, and in other terms, making decisions not in line with the public preferences. In particular, public
participation in post-disaster measures seems undoubtedly necessary to reduce the possible economic, social, political, and
cultural conflicts around the stressful community after a major disaster. This paper aims at evaluating the role of public
participation in increasing the reconstruction phase efficiency through a case study of the reconstruction process in Bam,
a southeastern Iranian city, after the 2003 earthquake. It is attempted to identify the major motivators of the public participation
through a combination of quantitative and qualitative studies. Statistical data are generated through a set of questionnaires
being filled by a number of 200 randomly selected survivors. The numerical results were then discussed through the Focus Group
technique sessions to determine the main contributors to the public participation. It is later found that the answers are
found among the performance of the reconstruction authorities, financial policies, emotional resiliency of the survivors,
public information mechanisms, public satisfaction, the pace of reconstruction, and temporary housing policies. 相似文献
17.
Being a large hyper‐saline water body, Lake Urmia in north‐western Iran deals with a gradual decline in its water level. Most of the studies on Lake Urmia have neglected the groundwater issue. In this study, as a direct approach, the interaction between the groundwater level and the lake water level is investigated both in time and space by analysing the groundwater data compiled from observation wells surrounding the lake. Baseflow separation is considered as an indirect approach to understand the groundwater contribution to the river network flowing into the lake. It is determined that about 70% of run‐off in the rivers draining into the lake is born in the form of baseflow. An interaction between the lake and the groundwater storage is clearly seen from the analysis to conclude that groundwater has a potential to recharge the lake. Thus, the shrinkage of water level in Lake Urmia could be expected to accelerate with the drastic use of groundwater, which will be a disaster with no return. 相似文献
18.
Flood occurrence has always been one of the most important natural phenomena, which is often associated with disaster. Consequently,
flood forecasting (FF) and flood warning (FW) systems, as the most efficient non-structural measures in reducing flood loss
and damage, are of prime importance. These systems are low cost and the time required for their implementation is relatively
short. It is emphasized that for designing the components of these systems for various rivers, climatic conditions and geographical
settings different methods are required. One of the major difficulties during implementing these systems in different projects
is the fact that sometimes the main functions of these systems are ignored. Based on a systematic and practical approach and
considering the components of these systems, it would be possible to extract the most essential key functions of the system
and save time, effort and money by this way. For instance, in a small watershed with low concentration and small lead time,
the main emphasis should be on predicting and monitoring weather conditions. In this article, different components of flood
forecasting and flood warning systems have been introduced. Then analysis of the FF and FW system functions has been undertaken
based on the value engineering (VE) technique. Utilizing a functional view based on function analysis system technique (FAST),
the total trend of FF and FW functions has been identified. The systematic trend and holistic view of this technique have
been used in optimizing FF and FW systems of the Golestan province and Golabdare watersheds in Iran as the case studies. 相似文献
19.
Bozorg-Haddad Omid Zolghadr-Asli Babak Chu Xuefeng Loáiciga Hugo A. 《Natural Hazards》2021,108(2):2385-2391
Natural Hazards - In March 2019, the Iranian meteorological organization warned of the formation of several dense precipitation systems throughout the country. This was followed by a chain of storm... 相似文献
20.
Reconstruction management policies in residential and commercial sectors after the 2003 bam earthquake in Iran 总被引：1，自引：1，他引：0
In the very early hours of 26th December 2003, a devastating and strong earthquake with a magnitude of 6.5 struck Bam, one
of the historical cities of Kerman province in the south of Iran. According to the official reports, more than 30,000 were
killed and about 25,000 injured. More than 80% of the town’s buildings were also destroyed. After the disaster, Bam’s reconstruction
management process was presented with a lot of challenges and faced many fundamental questions. The number of human losses
and related social issues, extensive destruction of the historical town, and also the lack of good experience in the reconstruction
of a city or town made the reconstruction project of Bam more complicated. The reconstruction of Bam was the most important
post-disaster reconstruction project among recent reconstructions in Iran. Many factors, such as concern over the government
and international agencies, the new managerial approaches, and the application of appropriate reconstruction methods, made
it different from the other reconstruction programs. Thus, the post-earthquake reconstruction of Bam is investigated in this
research with respect to the importance of this issue. The aim behind this article is to give a brief explanation of the earthquake
reconstruction management policies in Bam and also the plans for the reconstruction and rebuilding of urban residential and
commercial units. 相似文献