Let G be a finite group, Λ be a Z-order of group algebra QG, and Λ' be a maximal Z-order containing Λ. There is a homomorphism between locally free groups CL(Λ) and CL(Λ') which is induced by including map, and the kernel group D(Λ) is defined to be the kernel of this homomorphism. When G is a p-group, we give an estimate of the exponent of the kernel group D(ZG).

We establish a higher integrability for second derivatives of solutions to the nondivergence elliptic equations of the following type ,

where the coefficients a_ij(x) are bounded and have small BMO-norm, and b_i(x) and c(x) belong to Lⁿ(Ω) where Ω is a bounded smooth domain in Rⁿ(n≥3).

We mainly focus on the application of RBF neural networks in individual credit evaluation. Considering that the traditional RBF neural networks can only deal with the numerical value and that it is sensitive to the noisy data and the initial clustering centers, we propose a new RBF neural network combined with fuzzy K-Prototypes algorithm, which can deal with mixed data and is less sensitive to the noisy data and the initial clustering centers. The experimental results on the credit data show that the new RBF neural network has higher accuracy and robustness than the traditional one.

Instability of an electrically conducting fluid between two parallel plates, affected by an imposed transversal magnetic field, is numerically investigated by Chebyshev collocation method. The QZ method is utilized to obtain neutral curves of the linear instability. Details of instability are analyzed by solving the generalized Orr-Sommerfeld equation to determine the wavenumbers, growth rates, and spatial shapes of the eigenmodes.

Choice of a heat transfer model for buried tube-group heat exchangers (GHEs) is the key to accurate calculation of the heat exchange of GHEs in ground-coupled heat pump (GCHP) system. Based on practical projects, the 2D and 3D unsteady heat transfer models of vertical U-tube GHEs are constructed. With Fluent as a computational tool,the heat coupled calculations for a period of 15 years are carried out and soil temperature variation curves are obtained. By taking the 3D model numerical results as benchmark and goodness-of-fit as reference parameter, application conditions for the 2D model are analyzed.

Aggregation of the peptide amyloid-β (Aβ) into fibrils is considered to be closely related to the cause of Alzheimer disease (AD). Transition metals, such as Cu(Ⅱ), Zn(Ⅱ), and Fe(Ⅲ), are found in Aβ plaques and shown to affect Aβ aggregation. We investigated the interactions between those metal ions and the peptide amyloids (Aβ16 and Aβ28) by high-performance capillary electrophoresis coupled with UV detection (HPCE-UV). The experiments show that (i) the Zn²⁺, Cu²⁺, and Fe³⁺ ions interact with Aβ; (ii) Cu²⁺ rather than Zn²⁺ accelerates the aggregation of Aβ16 and the formation of oligomers. In addition, Zn²⁺ and Fe³⁺ accelerate the aggregation of Aβ28 with different acceleration rates.

CaSrTiMnO₆(CSTM) dielectric ceramic was synthesized by the solid-state reaction method. Rietveld refinement results indicate that the ceramic has orthorhombic structure with space group pnma. Only one dielectric relaxation was found in CSTM ceramic, and it can be well explained by the mixed-valent structure (Mn³⁺/Mn⁴⁺) and normalized bond length theory. Within a temperature range from 333 K to 453 K, the value of dielectric constant was nearly stabilized at 4 000 in low frequencies, which suggests its wide potential application in the field of high-temperature and low-frequency dielectric devices.

A full-length cDNA, designated as AtACO3, was isolated from Arabidopsis thaliana. Semi-quantitative RT-PCR revealed that AtACO3 was significantly activated under treatment with 200 μmol/L ZnCl₂ for 1 hour while inhibited under treatment with 200 μmol/L CuCl₂. To investigate the function of the N-terminus of AtACO3, the prokaryotic expression vector pET30a with a fragment of AtACO3 including 1632 bp from the initiation codon was constructed and successfully transformed E. coli. SDS-PAGE indicated that the recombinant N-terminus of AtACO3 was soluble and stable when expressed in E. coli. Additionally, the tolerance of E. coli against Zn²⁺ was found to be enhanced by expressing the N-terminus fragment of AtACO3.

The pattern that water use efficiency (WUS) decreased with precipitation is shown in spatical scale and it may be affected by both the genetic and environmental factors. Samples of Stipa grandis, collected at the same site during a period from 1983 to 1993 and common garden experiments, were used to study the relationship between the precipitation and WUE. The results show that WUE strongly decreases with precipitation in both the two experiments and that only the change in precipitation causes this pattern. The genetic effect needs further investigation.

Nitrogen pollution of groundwater in a typical catchment was investigated in order to understand the nitrogen contribution from groundwater to the serious eutrophication in Dianchi lake. The characteristics and patterns of temporal and spatial distribution of nitrogen in groundwater were obtained for the typical river catchment in Dianchi watershed. Additionally, four factors controlling variation in the nitrogen concentrations in groundwater, such as precipitation and N fertilizer applications, were indentified.

The support vector machine (SVM)-based relevance feedback algorithm has been used in common image retrieval, but not widely applied to remote sensing images. Traditional algorithm only uses SVM classifiers, resulting in some wrong ranking sequences of retrieval results. An improved relevance feedback strategy is proposed, and it modifies the similarity measurement criterion using a weighted linear combination of feature similarity measurement and SVM classifier. Experimental results show that the proposed method improves the ranking sequence and accuracy of retrieval results.

On the basis of Theil indexes, we analyzed the regional economic disparity(RED) inside Beijing during the period from 2001 to 2009. The results show that: 1) RED in Beijing has increased during the period; 2) RED in the inner city comes from the disparity among the northern four districts and between north and south urban regions; 3) the disparity among inner city, suburb, and exurb has the largest contribution to the general disparity; and 4) the main reasons for the RED are different nature conditions, different allocations of resource by the government, and competitive industries in some counties.

We propose a dynamic charge current adjusting method and have used it in solar panel-lithium battery charging system. A digital potentiometer controlled dynamically by a low power MCU is used to set the maximum charging current to LiFePO₄ from charging circuit. The method ensures effective implementation of the solar maximum power tracking (MPPT) and of the battery protection when low voltage or full charged.The test results show that the MPPT efficiency is up to 98.5%, the power conversion efficiency is up to 93.5%, and the maximum charge current is 3.96 A.

In order to enhance the bandwidth and the anti-jamming capacity of an optic-electronic tracker, a fiber communication system used for cameralink cameras was designed. The parallel data were serialized after they were processed in FPGA and transferred to the receiver by fiber.The receiver decoded serialized data to parallel data and sent them to frame grabber. A self-test function was used to verify whether communication is normal. The experimental results show that its self-test-function works normally, it transfers images in the base and medium configurations without errors, and the maximum bandwidth is 2 Gbps in a single channel.

Airborne forward-looking synthetic aperture radar (SAR) with linear array antennas based on frequency-modulated continuous-wave (FMCW) technology can obtain the image in front of the aircraft and it has the advantages of FMCW radar such as small size and lightweight. Moreover, it is suitable for installation on platforms like helicopter and small unmanned aerial vehicle. We analyze the echo model based on geometry of forward looking SAR with linear array antennas based on FMCW and the Doppler frequency shift due to the movement of the aircraft, propose a corresponding compensation scheme, and then present an improved frequency scaling algorithm based on FMCW forward looking SAR with linear array antennas. Finally, the algorithm is verified with the simulation.

The compression problem of InSAR image data is investigated. A new InSAR data compression method is presented, and it consists of an amplitude image compression and an interferogram compression. We provide the signal processing flow and two data compression methods on board which are based on DCT and DWT, respectively. The compression performance of InSAR image data is analyzed. In order to reject the speckles impact on interferogram, the pivoting median filter is applied before the interferogram is compressed. The processing results of real data and simulation data under different signal-to-noise ratios show the validity of our method.

Considering that most of abnormal behavior analysis methods do not consider the scene, we propose a method of abnormal behavior analysis based on latent topic model. Features of the scene are extracted and clustered to visual vocabulary by K-means. The visual vocabulary is divided into semantic topics to describe the scene by pLSA model. The descriptions for the scene and trajectory are combined to form feature vector which is modeled by CRF. Parameters of the CRF model are estimated by training, and abnormal behavior is analyzed by inference. The experiments show that abnormal behavior in a particular scene is accurately analyzed by this method.

We design and implement an omni-directional stepping robotic system based on cellular grid map to provide physical services in intelligent space. By analyzing and modeling the mobile platform in mechanics, kinematics, and dynamics, we design the robot suitable on cellular grid map, with the help of high-precision optical odometer based on FPGA and of laser calibration device. Based on multi-dimensional sensor data fusion, we make the path planning task into two stages: six-directional local path planning and global path planning based on TSP optimization of genetic algorithm. Experiments show the accuracy and robustness of the system during the actual operation.

Covert channel poses a threat to the confidentiality of high-level security databases. We study and summarize existing database covert channels based on the scenarios of use and propose a new method to classify database covert channels and to study their formation mechanisms. We propose several new constructing methods of database covert channels. In databases based on different DBMS we construct typical covert channels in real. The results of the comparative analysis show the possibility of the presentence of covert channels which are caused by the implementation defect.

A robust image zero-watermarking algorithm is proposed by using Haar transform and an improved geometric normalization method. The original image is first transformed into a standard image by using the improved geometric normalization method. The multilayer Haar transform is then applied to the standard image. Finally, the zero watermarks are constructed based on the high and intermediate frequency wavelet coefficients. Experimental results show that the algorithm has strong robustness resisting normal signal process as well as geometric attacks.

RESTful APIs have new features in styles of parameter and calling, and typical web flaw scanners perform poorly on these APIs. We designed and implemented the first SQL injection flaw detection tool called RASIVD targeting RESTful APIs. The experiment results show that, compared to traditional tools, RASIVD detects more API SQL injection flaws and has no false positive, which indicates the efficiency of RASIVD.

For multiple regenerative relay systems, we propose a multicast-aware linear transceiver-aided multi-stream multicast scheme to improve the system capacity when it is limited by relay-to-destination link. In this scheme, joint transmission of data-sharing relays is employed to improve the weak relay-to-destination link. To efficiently distribute the needed sharing data to relays, multi-stream multicasting is performed in source-to-relay link and we design a multicast-aware linear transceiver which intelligently collects same streams and separates different streams. The simulation results show that system capacity is effectively enhanced, especially for weak relay-to-destination link.