We aim to generalize gerbes to higher gerbes. This paper reviews the history of classification of D-brane charges as evidence for gerbes, then present a higher sheaf-stack procedure to investigate the n-gerbe structure.This study also considers examples on a fibred bundle. Our conclusion offers three equivalent conditions for stable isomorpoism.
Urban vegetation is an important parameter in urban temperature and climate study. We used NDVI and VF(vegetation fraction) generated from spectral mixture analysis as urban vegetation cover indicator factors to study the relationship between vegetation cover and LST (land surface temperature). We selected a number of typical samples and studied the relationships between LST and VF and between LST and NDVI based on the linear fitting method. The results indicated that the vegetation coverage decreased linearly as the temperature increased and the relationship between VF and LST was better than that between NDVI and LST. Our results show that VF can be used as vegetation character indicator in urban LST study.
The initial water temperature distribution is analyzed, focusing on the immobile water which is utilized for heat pump. A two-dimensional model of initial water temperature is established based on the control equations of water temperature and water flow. The numerical distribution of the water initial temperature is obtained, and the calculation results are analysed and compared with the measured data. The mode can be used in analysis of applicability of water surface heat pump and act as foundation of study on water temperature distribution characteristics under dynamic load.
Whether the Zipingpu reservoir triggered the 5.12 earthquake has attracted international attention. We discuss influences of the artificial load on stability of faults in the vicinity based on the solution of Boussinesq’s problem with the consideration of geometry of the reservoir and real water depth. The results indicate that the static Coulomb stress changes obviously near the surface and its magnitude can be 0.2MPa, but decreases rapidly with distance. The seismic source of the 5.12 earthquake was in the field where the static Coulomb stress changes are positive. However, the magnitude of about 0.005MPa is too small because of the remoteness from the reservoir. We also discuss the distribution of the static Coulomb stress caused by point load on some typical faults.
Using the previous experimental data at high pressure and high temperature, the main parameters of rheological law for olivine were discussed. The grain size range for the rheological change were determined by the theoretical discriminant. The main rheological mechanism and the viscosity in the 150 kilometers’ depth were preliminarily discussed, and a deformation map of strain rate-stress-grain size under certain conditions was obtained.
Fatty acid synthase (FAS) has been considered as a potential new therapeutic target for obesity. In the present study we show that the components of both strawberry ( Fragaria ananassa Duch) fruit dreg and strawberry leaves that extracted with 50% ethanol and partitioned by ethyl acetate are potent FAS inhibitors. The ethyl acetate fractions of strawberry fruit dregs (SF-AE) show noncompetitive inhibition with the substrate Mal-CoA, while the ethyl acetate fractions of strawberry leaves (SL-AE) show competitive inhibition with Ac-CoA. Based on the HPLC-MS analysis, we conclude that ellagic acid and quercetin are the efficient components. SF-AE and SL-AE could reduce lipids accumulation in 3T3-L1 preadipocyte with dose-dependence. These results may be of great value for application of strawberry extracts to obesity prevention and cure.
The angiotensin-converting enzyme (ACE) gene I/D polymorphism was detected in 82 cases of brain infarction (BI), 67 cases of simple essential hypertension (EH), and 95 normal cases (control). The relationship between the gene polymorphism and the hypertension disease complicated with brain infarction was evaluated. The frequencies of ACE D/D genotype and D allele (0.341 and 0.524) in the BI group were significantly higher than those in the control group (0.200 and 0.374, P<0.05) and EH group (0.179 and 0.358, P<0.05). The results suggest that ACE-DD variant may be significantly relevant to Chinese hypertensive patients with brain infarction.
In order to achieve low in-band phase noise in Σ-Δ fractional-N frequency synthesizers, a 5th-order 4bit Σ-Δ modulator is used to replace a 3rd-order MASH modulator. A 2.6GHz Σ-Δ fractional-N frequency synthesizer with low in-band phase noise and fast-locking characteristics was implemented in 0.25μm CMOS process. The measurement results show that the in-band phase noise of this synthesizer is -86.5dBc/Hz (at 40KHz offset), and all the spurs are less than - 65dBc. The whole synthesizer excluding the Σ-Δ modulator consumes 25.5mA in the case of 2.5V supply, and it occupies 3.9mm2(with a core area of 0.63mm2).
The time- and frequency-domain characteristics of transient electromagnetic disturbance caused by switching operations in substations were analyzed. Two methods were used in time-domain analysis. One was histogram and the other normality test. Appropriate procedures for the normality test were proposed and implemented by software. The method used in frequency-domain analysis was to compute overall envelope. These statistical characteristic analysis methods are showed to be of great value in analyses of the measured samples.
Compressed sensing theory is a novel data collection and coding theory under the condition that signal is sparse or compressible. It has been shown that when the measurement matrix satisfies RIP, the original signal can be reconstructed with observations which are far less than Nyquist rate samples. In this paper, we apply the compressed sampling scheme to a signal detection model and propose a detection method based on compressive sampling using minimax criterion. Theoretical analysis shows that this method can achieve good detection performance, which is also verified by Monte Carlo experiments.
Based on the signal model of SAR with linear array antennas, a three-dimensional imaging algorithm using elevation angle compression principle is proposed. Range cell migration correction (RCMC) is incorporated in the three-dimensional imaging algorithm. The three-dimensional imaging principle of SAR with linear array antennas is analyzed from the point of view of elevation angle compression principle. The simulation results support the signal model and three-dimensional imaging algorithm.
Based on the 802.11 MAC protocol model this study proposes a novel routing metric IAMM (interference-aware multipath metric) to quantify the inter-path interferences. Based on IAMM, an interference-aware multipath routing (IAMR) protocol is proposed. Through a dual path selection method, IAMR takes into account not only the performance of each single path but also the inter-path interference between selected paths. The result of simulation shows that IAMR significantly improves the performance on transmission throughput, end-to-end transmission delay, and arrival rate of packets.
This study focuses on how to optimize the communication radii of sensor nodes in hierarchically clustered sensor networks to minimize the total energy consumption. The energy model is E=a(dα+c), where R denotes the range of sensor networks and K is the number of layers. When the radii of sensor nodes are fixed, the upper bound of the optimal radii of sensor nodes is proved to be α c/(α-1) if α=2,c≤4R2, or if α=4, c≤4R2,K≤ 6 R. When the radii are adjustable and α=2, the radii are obtained by minimizing the average energy consumption layer by layer.
In this paper we describe the development of PKI interoperation and analyze the differences between interoperability of PKI transaction and interoperability of PKI entity. We propose a new model of PKI evaluation, which can be used to evaluate the interoperability of PKI entity. The model represents a way to promote interoperability of PKI entity and can be used to construct PKI entity with total interoperability.
In this paper, we present a positive result on deniable zero knowledge in the common reference string (CRS) model: an efficient transformation from Σ-protocol to deniable zero knowledge in CRS model. According to the lower bound given by Pass, for deniable zero knowledge in CRS model, our compiler achieves optimal round efficiency. In addition, the transformation induces only a small additive overhead in communication complexity.
We describe an algorithm for computing the zero-th and first Betti numbers of the union of compact semi-algebraic sets.The complexity of the algorithm is single exponential.
GH3 genes belong to a primary auxin-response gene family. The 10 promoter sequences of Arabidopsis GH3 genes were analyzed using bioinformatics method. The results show that the transcription start site of these genes is generally 65~145bp away from the start codon, and the TATA boxes are located in the (-24)-(-40)bp. MDB and MatInspector analyses show that most upstream regions of these GH3 genes contain the cis-elements required for tissue and organ-specific expression responding to phytohormones and external environment, indicating that the expressions of GH3 genes are strictly controlled by multi-factors. Gene chip data show that AuxREs is very important for GH3 genes in response to IAA treatment,but it is not the unique cis-element for auxin response.
Considering the problems in traditional multi-bandwidth synthetic aperture radar (SAR) system, such as too many filters and sampling clocks, we present a new digital processing scheme. This scheme needs only one highest frequency sampling clock to obtain the discrete data; other data with lower frequencies can be acquired by interpolation; and digital filter fulfills the function of filtering signals with different bandwidths. This technique simplifies the design of the SAR system and improves the reliability. The architecture of the algorithm, the simulation results, and the implementation of the algorithm based on FPGA are expounded in detail.
Fuzzy clustering method can be used to divide the different software requirements into classes, and the grey correlation degree analysis can identify the levels of importance for the requirements in each class.This analysis method can provide a scientific resolution for the requirement management.