排序方式： 共有9条查询结果，搜索用时 15 毫秒
1
1.
The magnetic anomaly ΔF due to a long horizontal cylinder yields three points related to its extrema. A nomogram is presented for the determination of some source parameters of the causative body. 相似文献
2.
3.
The chemical oxygen demand (COD) parameter of a wastewater treatment plant is predicted based on wavelet decomposition, entropy, and neural networks (NN) for rapid COD analysis. This paper also describes the usage of wavelet and NNs for parameter prediction. Data from a wastewater treatment plant in Malatya, Turkey, were used. This dataset consists of daily values of influents and effluents for a year. To reduce the dimension of input parameters and to decrease the NN training time, wavelet decomposition and entropy were used. Test results were presented graphically. The test results of the trained model were found to be closer to the measured COD values. 相似文献
4.
In this study, a Markov Random Field (MRF) approach is used to locate source boundary positions which are difficult to identify
from Bouguer gravity and magnetic maps. As a generalized form of Markov Chains, the MRF approach is an unsupervised statistical
model based algorithm and is applied to the analysis of images, particularly in the detection of visual patterns or textures.
Here, we present a dynamic programming based on the MRF approach for boundary detection of noisy and super-positioned potential
anomalies, which are produced by various geological structures. In the MRF method, gravity and magnetic maps are considered
as two-dimensional (2-D) images with a matrix composed of N1 × N2 pixels. Each pixel value of the matrix is optimized in real time with no a priori processing by using two parameter sets; average steering vector (θ) and quantization level (M). They carry information about the correlation of neighboring pixels and the locality of their connections. We have chosen
MRF as a processing approach for geophysical data since it is an unsupervised, efficient model for image enhancement, border
detection and separation of 2-D potential anomalies. The main benefit of MRF is that an average steering vector and a quantization
level are enough in evaluation of the potential anomaly maps. We have compared the MRF method to noise implemented synthetic
potential field anomalies. After satisfactory results were found, the method has been applied to gravity and magnetic anomaly
maps of Gelibolu Peninsula in Western Turkey. Here, we have observed Anafartalar thrust fault and another parallel fault northwest
of Anafartalar thrust fault. We have modeled a geological structure including a lateral fault, which results in a higher susceptibility
and anomaly amplitude increment. We have shown that the MRF method is effective to detect the broad-scale geological structures
in the Gelibolu Peninsula, and thus to delineate the complex tectonic structure of Gelibolu Peninsula. 相似文献
5.
6.
Davut?AydoganEmail author Ali?Elmas A.?Muhittin?Albora Osman?N.?Ucan 《Marine Geophysical Researches》2005,26(1):1-15
In this study, structural features in the Aegean Sea were investigated by application of Cellular Neural Network (CNN) and
Cross-Correlation methods to the gravity anomaly map. CNN is a stochastic image processing technique, which is based on template
optimization using neighbourhood relationships of pixels, and probabilistic properties of two-Dimensional (2-D) input data.
The performance of CNN can be evaluated by various interesting real applications in geophysics such as edge detection, data
enhancement and separation of regional/residual potential anomaly maps. In this study, CNN is used in edge detection of geological
bodies closer to the surface, which are masked by other structures with various depths and dimensions. CNN was first tested
for (prismatic) synthetic examples and satisfactory results were obtained. Subsequently, CNN/Cross-Correlation maps and bathymetric
features were evaluated together to obtain a new structural map for most of the Aegean Sea. In our structural map, the locations
of the faults and basins are generally in accordance with the previous maps from restricted areas based on seismic data. In
the southern and southeastern parts of the Aegean Sea, E–W trending faults cut NE–SW trending basins and faults, similar to
on-shore Western Anatolia. Also, in the western, central and northern parts of the Aegean Sea, all of these structures are
truncated by NE-trending faults. 相似文献
7.
The physical process of oxygen transfer or oxygen absorption from the atmosphere acts to replenish the used oxygen, a process termed re‐aeration or aeration. Aeration enhancement by macro‐roughness is well‐known in water treatment and one form is the aeration cascade. The macro‐roughness of the steps significantly reduces the flow velocities and leads to flow aeration along the stepped cascade. In this paper, the aeration efficiency in stepped cascade aerators was modeled by using the Adaptive Network Based Fuzzy Inference System (ANFIS). The obtained model was tested with experimental data. Test results showed that ANFIS can be used to estimate the aeration efficiency in stepped cascade aerators. 相似文献
8.
Davut Yılmaz Fatih Babuçcu Serhat Batmaz Fatih Kavruk 《Geotechnical and Geological Engineering》2008,26(2):211-224
Beydag dam is under construction on Kucukmenderes River for irrigation purposes. Due to the scarcity of core material and
liquefaction of alluvium at the dam site, the original design was changed to Roller Compacted Concete (RCC) from rockfill
dam with claycore. Although the new design was safer, it nearly doubled the cost of the dam, so the owner, State Hydraulic
Works of Turkey, (DSI) set out to find more economical but equally safe alternative. Since jet-grouting is a cheap ground
improvement tool in Turkey, such an alternative was developed for the ground improvement against liquefaction together with
concrete face rockfill dam sitting on top of improved ground. This paper presents a detailed discussion of how the new alternative
was developed and evaluated: it discusses the determination of jet grouting pattern, the placement of jet grouted blocks,
and the assesment of liquefaction. On one hand the soil cement strength of jetgrout columns, internal friction angle of alluvium
and rockfill were important in determining the dimensions of the blocks, on the other hand the location of the blocks were
highly affected by the areas where liquefaction occurred. One of the most important parameter that has a considerable influence
in delineating the boundary betweeen liquefaction and non-liquefaction was the value of stress reduction coefficient (r
d), being primarily sensitive to the weight of overburden, which is calculated by the height from the face of dam to the depth
where the calculation was made. This approach is justified by two-dimensional ground response analysis. Most importantly,
this paper shows that there exists an alternative solution for building dams on the liquefaction prone sites without removing
alluvium by using a well known jet grouting technique for improving ground at only selected places. 相似文献
9.
Yalcin Yuksel Berna Ayat Mehmet Nuri Ozturk Burak Aydogan Isikhan Guler Esin Ozkan Cevik Ahmet Cevdet Yalçıner 《Ocean Engineering》2008,35(13):1304-1321
The Bosphorus is oceanographically very complicated two-layer stratified strait where denser water from the Marmara Sea flows towards North under the lighter water which is frequently flowing from the Black Sea towards South. The water level difference between both ends of the Bosphorus varies seasonally within the range of ?0.2 and 0.6 m. The seasonal variability depends mainly on the water level changes in the adjacent basins related to the hydrological cycle, short-term changes in the atmospheric pressure and the wind characteristics. These variations together with the depth and alignment of the cross section along the strait dominate the spatial and temporal variations and sometimes sharp changes in the flow pattern in three dimensions. Although these hydrodynamic conditions are critical for all marine and hydraulic works along the Bosphorus, there was not continuous long-term measurement for a sufficient time span in the strait for detailed evaluation of the current climate. An extensive site surveying work including current, wind, pressure and water level measurements was carried out between September 2004 and January 2006 in relation to the design and construction requirements of the Bosphorus Tube Crossing Project. In this study, the characteristics of stratified flow in the Bosphorus Strait and their relation to local and regional, short- and long-term changes in the meteorological parameters are studied by using the measurement data and the results are discussed comparatively. 相似文献
1