Simulation and Prediction on Space-Time Distribution of Water Quality in Dianchi Lake

It is very important in pollution treatment to clarify the space-time distribution of water quality in Dianchi Lake. Based on the sample data obtained from 10 observation stations every month from 2008 to 2009, it uses space-time semi-variogram and ordinary kriging method to simulate the space-time variance and distribution of water quality indictors (TN, TP, BOD, CODMn, DO, Chlorophyl-α, etc.). Because the space-time semivariogram also has a certain of ex-trapolation function. From the simulation results, the pollution is mainly concentrated at the North (Caohai) and the Southwest area (Haikou), and water pollution has a increase trend.

Seasonal Contrast of Some Anthropic Pollution Parameters in Water Retention in Mountainous Area under Sahelian Climate: Elementary Dynamics and Space Distribution (Territory of the Mounts Mandara, Cameroon)

In order to understand the origin, the extent and the space distribution of the seasonal anthropic pollution parameters in the water retention located in mountainous area thickly populated and which water resources is intended for the production of drinking water for serving a population of approximately 800,000 inhabitants, two sampling campaigns were carried out for the two seasons of the year known as the dry and rainy season. The samples were then conveyed and analyzed in laboratory. The parameters retained for this study were primarily the physicochemical parameters (pH, conductivity and temperature), measured in situ and second the major anthropic origins anions of (, , and ). The results of the study show that overall the anthropic pollution parameters undergo an important seasonal variation of their concentration between the dry and rainy periods although they remain high in any season compared to the quality standards of natural water of the European Union. Their space distribution within retention remains overall random and is not function of the seasons. However, surrounding areas of the retention and the discharge system of the seasonal rivers (Mayos) which feed it present in rainy season space distributions of concentrations in anions of anthropic origin enumerated above highest.

On analyzing space-time distribution of evaporation duct height over the global ocean

The statistical features of the evaporation duct over the global ocean were comprehensively investigated with reanalysis data sets from the National Centers for Environmental Prediction. These data sets have time and spatial resolutions of 1 h and 0.313°x0.312°, respectively. The efficiency of the analysis was evaluated by processing weather buoy data from the Pacific Ocean and measuring propagation loss in the Yellow Sea of China. The distribution features of evaporation duct height （EDH） and the related meteorological factors for different seas were analyzed. The global EDH is generally high and demonstrates a latitudinal distribution for oceans at low latitudes. The average EDH is approximately 11 m over oceans beside the equator with a latitude of less than 20°. The reasons for the formation of the global EDH features were also analyzed for different sea areas.

Joint DOA and time delay estimation method for space-time coherent distributed signals based on search

Under dense urban fading environment, performance of joint multi-path parameter estimation method based on traditional point signal model degrades seriously. In this paper, a new space and time signal model based on multipath distribution function is given after new space and time manifold is reconstructed. Then joint spacetime signal subspace is obtained by converting acquired channel from time domain to frequency domain .Then space and time spectrum is formulated by the space sub-matrix and time sub-matrix taken out of joint space-time signal subspace, and parameters are estimated by searching the minimum eigenvalues of the space matrix and the time matrix. Lastly, A space and time parameters matching process is performed by using the orthogonal property between joint noise subspace and the space-time manifold. In contrast with tradition MUSIC, the algorithm we present here only need two 1- dimension searching and was not sensitive to different distribution function.

Space-time Dynamics of Dendroctonus valens Population in China and Spatial Sampling Technique based on Its Spatial Distribution Pattern

Red turpentine beetle （RTB）, Dendroctongs valens LeConte, is a destructive forest invasive species in China, it mainly attacks Pings tabuliformis and P. bungeana. So far it has spread rapidly to the provinces of Shanxi, Hebei, Henan, Shanxi and Beijing since its first outbreak in Shanxi Province in 1998, and has caused extensive tree mortality. Space-time dynamics of D. valens population and spatial sampling technique based on its spatial distribution pattern were ana- lyzed using geostatistical methods in the pure P. tabuliforis forests and mixedwood stands which were at different damage levels. According to the spatial distribu- tion of D. valeas population, the specific spatial sampling technique was also studied, and then was compared with traditional sampling technique. The spatial sam- piing technique combined with sampling theory and the biological characteristics of D. valens population, which not only could calcnlate the error of the sampling, but also could discuss the optimal sampling number and the optimum size of plot according to different damage levels and different stand types. This helps to explain population expansion and colonization mechanism of D. valens, and to provide a good reference for adopting snitable control measures.

A Method for Improving Power Distribution Characteristics of Space Time Block Codes

Improving power distribution characteristics of space time block codes(STBCs),namely peak to average power ratio(PAPR),average to minimum power ratio(Ave/min),and probability of transmitting"zero"by antenna,makes easier their practical implementation.To this end,this study proposes to multiply full diversity STB C with a non-singular matrix in multiple input multiple output(MIMO)or multiple input single output(MISO)systems with linear or maximum likelihood(ML)receivers.It is proved that the obtained code achieves full diversity and the order of detection complexity does not change.The proposed method is applied to different types of STBCs.The bit error rate(BER)and power distribution characteristics of the new codes demonstrate the superiority of the introduced method.Further,lower and upper bounds on the BER of the obtained STBCs are derived for all receivers.The proposed method provides trade-off among PAPR,spectral efficiency,energy efficiency,and BER.

Mathematical model of flow characteristic in multi-strand continuous casting tundishes

In this paper, the subject of mathematical model is a series of math expressions, which is used to calculate different regions＇ volume fraction and analyze flow characterization in multi-strand tundish. But research about mathematical model for multi-strand tundish is few, and so far, there has been no acknowledged math model for multi- strand tundish to describe its flow characteristic. If Sahai＇s model, which is originally proposed for the case of single-strand tundish （proposed in reference, and this model is widely used in the world）, is applied to describe flow feature in multi-strand tundish, the calculation results would be unreasonable. Based on the data of watermodel experiment results, the sum of each strand＇s dead region＇s volume fraction is bigger than 100%, and this obviously doesn＇T agree with reality; and the value of dead region＇s volume fraction is calculated to be minus according to mathematical simulation results data in another case. What＇s more, Sahai＇s model does not propose the standard of plotting the RTD-curve, and this makes scholars around the world can＇t achieve consensus of views about plotting RTD-curve. And the model doesn＇t consider the bypass flow and can＇t calculate its volume fraction, but bypass flow is critical to tundish metallurgy. And through Sahai＇s model, the calculation result of plug flow region＇s volume fraction is also not reasonable, because the model doesn＇t well describe the essence of plug flow. So these suggest that it is not reliable to apply Sahai＇s single-strand tundish model to multi-strand tundish case. Then a new model is attempted to propose in this paper for your discussion. In the new model, the standard of plotting RTD curve is definitely proposed, and relative calculation method is also proposed; and the feature of dead region is carefully studied and the model proposes a new method to calculate its volume fraction, and the calculation formula about its volume fraction can be adjustable according the actual demand; what＇s more, the new model considers the bypass flow and proposes a method to calculate its volume fraction for the first time, and then volume fraction of plug flow region, backmix flow region, dead region and bypass flow can be calculated and obtained at the same time; and this new model can better capture the deviation of reality flow pattern from ideal plug flow pattern, and reflects the feature of plug flow.

Time History Dynamic Analysis of a New Constructed Offshore Jacket Platform in Persian Gulf Due to Random Waves

API RP2AWSD is a design code in practice for design of jacket platforms in the Persian Gulf but is based on the Gulf of Mexico environmental condition. So for the sake of using this code for the Persian Gulf, it is better to perform a calibration based on this specific region. Analysis and design of jacket platforms based on API code are performed in a static manner and dynamic analysis is not recommended for such structures. Regarding the fact that the real behavior of the offshore jacket platforms is a dynamic behavior, so in this research, dynamic analysis for an offshore jacket platform in the Persian Gulf under extreme environmental condition is performed using random time domain method. Therefore, a new constructed offshore jacket platform in the Persian Gulf is selected and analyzed. Fifteen, 1-h storm, simulations for the water surface elevation is produced to capture the statistical properties of extreme sea condition. Time series of base shear and overturning moment are derived from both dynamic and static responses. By calculating the maximum dynamic amplification factor (DAF) from each simulation and fitting the collected data to Weibull distribution, the most probable maximum extreme (MPME) value for the DAF is achieved. Results show that a realistic value for DAF for this specific platform is 1.06, which is a notable value and is recommended to take into practice in design of fixed jacket platform in the Persian Gulf.

Improved scheme with cooperative diversity based on distributed space-time block coding

An improved scheme with cooperative diversity based on distributed space-time block coding （WCD- DSTBC） is proposed, which effectively achieves diversity gains and improves the performance of the system by sharing some single-antenna users＇ antennas to form a virtual antenna array and combining with distributed spacetime block coding （DSTBC） mode. Then the relation between the system BER and the interuser BER for WCDDSTBC scheme is theoretically derived and the closed-form expression of BER for WCD-DSTBC system is obtained. The simulation results show that the proposed WCD-DSTBC scheme achieves distinct gains over the non-cooperative multi-carrier CDMA （MC-CDMA） system. When system BER is le-3 and interuser BER is le-3, about 2.5 dB gain can be gotten. When interuser channel state information （CSI） outgoes the users＇ individual CSI, about 3 dB gain is also achieved.

Distribution of Random Session Key Based on Key-Insulated Public-Key Cryptosystems

Based on the characteristic of key-insulated public-key cryptosystem, wepropose a distributed landora session keys distribution protocol without a key distribution center.The session key is generated by different user and only used one time. So thekey is one-time key. Inaddition, the user who generates the next one-time key, is random selected by the current sessionkey. In the protocol of this paper, the characteristic of time in the key-insulated public-key, adistributed protocol, translates into the characteristic of spaee which every point has differentsecret key in the different period. At the same time, the system is fit for key management in AdHoe, and is a new scheme of key management in Ad Hoc.

Hydraulic modeling of an anaerobic expanded bed reactor for municipal sewage treatment

Anaerobic expanded bed reactor(AEBR) is mostly used for the treatment of fairly low strength wastewaters. Since the performance of AEBR largely depends on its hydraulic characteristics, residence time distribution(RTD) method is commonly used for investigation of the hydraulic characteristics of AEBR under different ascending velocity of mixed liquor. In this paper, a pilot-scale AEBR reactor is investigated for treatment of municipal sewage in which lithium chloride is used as a tracer. The results show that the AEBR could be considered as the superimposition of several constant stirred tank reactors(CSTR) and the increase of hydraulic up-flow velocity could increase the number of the CSTR and decrease the volume rate of the dead zone. The optimal up-flow velocity of the investigated AEBR was approximately 1.9 m/h in the municipal sewage treatment.

Genesis and significance of quartz cement in sandstones

Quartz cement as syntaxial overgrowths is one of the most abundant cements in sandstones. Distribution of quartz cement in time and space indicates that the more younger the stratigraphy is, the more smaller the amount of quartz cement, and the amount of quartz cement increases with increasing of depth and basin type also is a factor which controls the amount of quartz cement. The sources of silica for quartz cement have many different opinions, but there is one or more dominant sources. Temperature and pH of fluid are major factors which influence the precipitation of quartz cement. There exist three hypotheses on the flow of pore fluid and transport and precipitation of silica, that is, the hypothesis of cycle of shallow underground water, the hypothesis of high concentration of fluid driven by compaction and the hypothesis of diffusion and recycle of local fluid. The research of quartz cement is significant for the timing of paleotemperature, heterogeneity of reservoir, physical property of reservoir and the timing of oil immersion, etc.

Space-Time Properties as Quantum Effects. Restrictions Imposed by Grothendieck’s Scheme Theory

In this paper we consider properties of the four-dimensional space-time manifold M caused by the proposition that, according to the scheme theory, the manifold M is locally isomorphic to the spectrum of the algebra A, M ≅Spec (A), where A is the commutative algebra of distributions of quantum-field densities. Points of the manifold M are defined as maximal ideals of density distributions. In order to determine the algebra A, it is necessary to define multiplication on densities and to eliminate those densities, which cannot be multiplied. This leads to essential restrictions imposed on densities and on space-time properties. It is found that the only possible case, when the commutative algebra A exists, is the case, when the quantum fields are in the space-time manifold M with the structure group SO (3, 1) (Lorentz group). The algebra A consists of distributions of densities with singularities in the closed future light cone subset. On account of the local isomorphism M ≅Spec (A) , the quantum fields exist only in the space-time manifold with the one-dimensional arrow of time. In the fermion sector the restrictions caused by the possibility to define the multiplication on the densities of spinor fields can explain the chirality violation. It is found that for bosons in the Higgs sector the charge conjugation symmetry violation on the densities of states can be observed. This symmetry violation can explain the matter-antimatter imbalance. It is found that in theoretical models with non-abelian gauge fields instanton distributions are impossible and tunneling effects between different topological vacua | n> do not occur. Diagram expansion with respect to the -algebra variables is considered.

Was Polchinski Wrong? Colombeau Distributional Rindler Space-Time with Distributional Levi-CivitàConnection Induced Vacuum Dominance. Unruh Effect Revisited

The vacuum energy density of free scalar quantum field in a Rindler distributional space-time with distributional Levi-Cività connection is considered. It has been widely believed that, except in very extreme situations, the influence of acceleration on quantum fields should amount to just small, sub-dominant contributions. Here we argue that this belief is wrong by showing that in a Rindler distributional background space-time with distributional Levi-Cività connection the vacuum energy of free quantum fields is forced, by the very same background distributional space-time such a Rindler distributional background space-time, to become dominant over any classical energy density component. This semiclassical gravity effect finds its roots in the singular behavior of quantum fields on a Rindler distributional space-times with distributional Levi-Cività connection. In particular we obtain that the vacuum fluctuations have a singular behavior at a Rindler horizon . Therefore sufficiently strongly accelerated observer burns up near the Rindler horizon. Thus Polchinski’s account doesn’t violate the Einstein equivalence principle.

Spatial Distribution of <i>Anopheles sinensis</i>and Its Relationship with Natural Environmental Factors in Wanning County on Hainan Island, China

Anopheles sinensis is widely distributed in Wanning County, it is necessary to understand the spatial distribution characteristics of Anopheles sinensis in order to maintain the elimination of malaria in Wanning. During May and October 2009, we sampled adult mosquitoes at 36 villages within Wanning County on Hainan island, and collected meteorological and geographical data at each sampling site. We used these data to analyze the spatial distribution of adult Anopheles sinensis mosquitoes, and logistic regression analysis was applied to explore the association of the spatial distribution of Anopheles sinensis with the geographical and meteorological factors. We found that the density of Anopheles sinensis showed a significant positive spatial correlation. From May to October, on the whole, the high-density area was located in the central part of Wanning County. But each month there was a relatively high-density cluster, and their location and range were not exactly the same. From east to west, the density of Anopheles sinensis increased initially and then decreased, but from south to north, there were different trends in the periods of May to August and September to October. Logistic regression analysis showed that the main environmental factors related with the distribution of Anopheles sinensis were land use type, soil type, distance to road, air pressure and relative humidity. These analysis results showed that the distribution of Anopheles sinensis had obvious spatial heterogeneity in Wanning County, which was related with geographical and meteorological factors. The mechanism of these environmental factors on the distribution of Anopheles sinensis needs to be further studied.

Analysis of Internal Moisture Change of Camphor Seeds during Drying by Low-Field NMR

In this study,low-field nuclear magnetic resonance(LF-NMR)was used to collect the transverse relaxation signals of camphor seeds that had been dried at different temperatures and for different durations.The transverse relaxation time of the hydrogen nucleus was obtained by SIRT(Simultaneous Iterative Reconstruction Technique)inversion,and the correlation between the moisture content on dry basis and the amplitude of NMR signal of camphor seeds sampled at different drying stages was analyzed.The results showed that water existed in three main forms strongly bound water,weakly bound water and free water in camphor seeds.During the drying process,the peak position of strongly bound water remained unchanged,but the peak positions of weakly bound water and free water fluctuated.Drying rate increased with drying temperature increasing.In addition,there was a very significant linear relationship between the total NMR signal amplitude and moisture content on dry basis,and the correlation coefficient reached 0.984 4.

Mine water discharge prediction based on least squares support vector machines

In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio method was used to determine embedding parameters to reconstruct the phase space.We used a multi-layer adaptive best-fitting parameter search algorithm to estimate the LS-SVM optimal parameters which were adopted to construct a LS-SVM prediction model for the mine water chaotic time series.The results show that the simulation performance of a single-step prediction based on this LS-SVM model is markedly superior to that based on a RBF model.The multi-step prediction results based on LS-SVM model can reflect the development of mine water discharge and can be used for short-term forecasting of mine water discharge.

Model-based Predictive Control for Spatially-distributed Systems Using Dimensional Reduction Models

In this paper, a low-dimensional multiple-input and multiple-output （MIMO） model predictive control （MPC） configuration is presented for partial differential equation （PDE） unknown spatially-distributed systems （SDSs）. First, the dimension reduction with principal component analysis （PCA） is used to transform the high-dimensional spatio-temporal data into a low-dimensional time domain. The MPC strategy is proposed based on the online correction low-dimensional models, where the state of the system at a previous time is used to correct the output of low-dimensional models. Sufficient conditions for closed-loop stability are presented and proven. Simulations demonstrate the accuracy and efficiency of the proposed methodologies.

Dynamic energy spectrum and energy deposition in solid target by intense pulsed ion beams

A method for analyzing the dynamic energy spectrum of intense pulsed ion beam(IPIB) was proposed.Its influence on beam energy deposition in metal target was studied with IPIB produced by two types of magnetically insulated diodes(MID).The emission of IPIB was described with space charge limitation model,and the dynamic energy spectrum was further analyzed with time-of-flight method.IPIBs generated by pulsed accelerators of BIPPAB-450(active MID) and TEMP-4M(passive MID) were studied.The dynamic energy spectrum was used to deduce the power density distribution of IPIB in the target with Monte Carlo simulation and infrared imaging diagnostics.The effect on the distribution and evolution of thermal field induced by the characteristics of IPIB dynamic energy spectrum was discussed.