适合大样本快速训练的最大夹角间隔核心集向量机

许多核化形式的分类方法如SVM,SVDD等都是对应一个二次规划(QP)问题,而核矩阵计算需要O(m2)空间复杂度,求解QP需要O(m3)时间复杂度,限制了这类方法对大样本数据的训练.本文基于一种新的分类间隔概念提出最大向量夹角间隔分类器MAMC,目标是在样本空间找到最优向量c,测试样本通过c与训练样本之间的最大化向量夹角间隔ρ(称为Margin)实现分类.同时,文中证明了该方法的核化形式等价于核化的最小包络球MEB问题,并通过引入核心集向量机CVM将MAMC扩展为MAM-CVM,进而快速实现对大样本的训练和分类.人造和真实数据集实验表明了MAMC和MAM-CVM算法的有效性.

Leptin levels in the differential diagnosis between benign and malignant ascites

AIM： To evaluate the role of leptin levels in the differentia diagnosis of ascites. METHODS： Ascitic leptin, TNFα and serum leptin levels were measured in 77 patients with ascites （35 with malignancies, 30 cirrhosis and 12 tuberculosis）. Control serum samples were obtained from 20 healthy subjects. Leptin and TNFα levels were measured by EUSA. Body mass index （BMI） and percentage of body fat （BFM） by skin fold measurement were calculated for all patients and control groups. Peritoneal biopsy, ascites cytology and cultures or biochemical values were used for the diagnosis of patients. RESULTS： In patients with malignancies, the mean serum and ascites leptin levels and their ratios were significantly decreased compared to the other patient groups and controls. In tuberculosis peritonitis, ascitic fluid TNFα levels were significantly higher than malignant ascites and cirrhotic sterile ascites. BMI and BFM values did not distinguish between patients and controls. CONCLUSION： In patients with malignant ascites, levels of leptin and TNFα were significantly lower than in patients with tuberculous ascites.

cDNA cloning, prokaryotic expression and purification of rat α-synuclein

Objective To clone the cDNA of rat α-Syn gene, investigate its prokaryotic expression and produce purified recombinant rat α-Syn protein. Methods Rat α-Syn cDNA was amplified from the rat brain total RNA by RT-PCR and was cloned into pGEX-4T-1, a prokaryotic expressing vector. The recombinant plasmid containing rat α-Syn gene was transformed into E. Coli BL21 to express a fusion protein with rat α-Syn protein tagged by glutathione-S-transferase （GST）. The fusion protein was then cleaved by thrombin during passing through the GST-agarose 4B column to release the recombinant rat α-Syn protein. The recombinant rat a-Syn protein was further purified using Superdex S200 gel filtration. Results DNA sequencing confirmed that the cloned cDNA contained 420 base pairs encoding 140 amino acids, which was identical to the reported amino acid sequence of rat α-Syn. After transformation, the recombinant plasmid pGEX-ra-Syn expressed a soluble protein that was inducible by IPTG. The purified recombinant protein was shown to be single band on SDS-PAGE, with a molecular size of around 18000, which was identical to the reported molecular size of rat α-Syn. Western blot analysis demonstrated that the recombinant protein was recognized by specific antibody against α-Syn. Conclusion The rat α-Syn gene was successfully expressed in prokaryotic expression system and highly purified rat α-Syn recombinant protein was produced.

Dihydrochalcones and phenanthrene derivatives from Fissistigma bracteolatum

Three dihydrochalcones derivatives 1-3, flavone 4 and phenanthrene derivative 5 were isolated, together with 9 known compofinds, from the air-dried root bark of Fissistigma bracteolatum Chatterjee. Their structures were determined by spectroscopic （NMR, MS） and chemical methodologies.

Model identification of continuous stirred tank reactor based on QKLMS algorithm

The continuous stirred tank reactor(CSTR)is one of the typical chemical processes.Aiming at its strong nonlinear characteristics,a quantized kernel least mean square(QKLMS)algorithm is proposed.The QKLMS algorithm is based on a simple online vector quantization technology instead of sparsification,which can compress the input or feature space and suppress the growth of the radial basis function(RBF)structure in the kernel learning algorithm.To verify the effectiveness of the algorithm,it is applied to the model identification of CSTR process to construct a nonlinear mapping relationship between coolant flow rate and product concentration.In additiion,the proposed algorithm is further compared with least squares support vector machine(LS-SVM),echo state network(ESN),extreme learning machine with kernels(KELM),etc.The experimental results show that the proposed algorithm has higher identification accuracy and better online learning ability under the same conditions.

Automatic Verification of Biochemical Network Using Model Checking Method

This study focuses on automatic searching and verifying methods for the teachability, transition logics and hierarchical structure in all possible paths of biological processes using model checking. The automatic search and verification for alternative paths within complex and large networks in biological process can provide a considerable amount of solutions, which is difficult to handle manually. Model checking is an automatic method for verifying if a circuit or a condition, expressed as a concurrent transition system, satisfies a set of properties expressed in a temporal logic, such as computational tree logic （CTL）. This article represents that model checking is feasible in biochemical network verification and it shows certain advantages over simulation for querying and searching of special behavioral properties in biochemical processes.

A Novel Systematic Method of Quality Monitoring and Prediction Based on FDA and Kernel Regression

A novel systematic quality monitoring and prediction method based on Fisher discriminant analysis (FDA) and kernel regression is proposed. The FDA method is first used for quality monitoring. If the process is un-der normal condition, then kernel regression is further used for quality prediction and estimation. If faults have oc-curred, the contribution plot in the fault feature direction is used for fault diagnosis. The proposed method can ef-fectively detect the fault and has better ability to predict the response variables than principle component regression (PCR) and partial least squares (PLS). Application results to the industrial fluid catalytic cracking unit (FCCU) show the effectiveness of the proposed method.

OPKH: A Lightweight Online Approach to Protecting Kernel Hooks in Kernel Modules

Kernel hooks are very important con- trol data in OS kernel. Once these data are com- promised by attackers, they can change the control flow of OS kemel＇s execution. Previ- ous solutions suffer from limitations in that： 1） some methods require modifying the source code of OS kernel and kernel modules, which is less practical for wide deployment; 2） other methods cannot well protect the kernel hooks and function return addresses inside kernel mo- dules whose memory locations cannot be pre- determined. To address these problems, we propose OPKH, an on-the-fly hook protection system based on the virtualization technology. Compared with previous solutions, OPKH off- ers the protected OS a fully transparent envi- ronment and an easy deployment. In general, the working procedure of OPKH can be di- vided into two steps. First, we utilise the me- mory virtualization for offiine profiling so that the dynamic hooks can be identified. Second, we exploit the online patching technique to in- strument the hooks for run-time protection. The experiments show that our system can pro- tect the dynamic hooks effectively with mini- mal performance overhead.

The Optimization of Decontamination Methods Selected for Contaminated Areas Used in Decommissioning of CANDU-6 NPP

The objective of this paper is to provide information for nuclear field specialists and decision makers on opportunities for minimizing radioactive wastes arising from the decontamination ＆ decommissioning of a CANDU-6 NPP. The paper proposes a method for selection of appropriate decontamination techniques which may be used at Cernavoda NPP decommissioning, equipped with CANDU heavy water reactors, based on the simulation with ProVision software. The paper has a singular focus on physical decontamination techniques and does not address other aspects of decommissioning. The physical decontamination techniques which are the best for certain areas of the CANDU-6 NPP from point of view of effectiveness and cost were determined. A unit cost for each decontamination technique was determined by relating the total cost to the average surface to be decontaminated. In conclusion, physical techniques will apply more efficiently to concrete surfaces. The chemical decontamination methods, in comparison with physical decontamination methods are. more suitable for non-porous surfaces respectively metal and are less recommended for concrete surfaces.

Synthesis of Ag@Cu_2O core-shell metal-semiconductor nanoparticles and conversion to Ag@Cu core-shell bimetallic nanoparticles

Ag@Cu2O core-shell metal-semiconductor nanoparticles(NPs) were prepared by using solution phase strategy. It was found that Ag@Cu2O core-shell NPs were easily converted to Ag@Cu bimetallic core-shell NPs with the help of surfactant PVP and excessive reducer ascorbic acid in air at room temperature, which is a unique phenomenon. Varying volumes of Ag colloidal solutions were added into the reaction mixtures containing fixed initial concentrations of Cu2+ and PVP, Ag@Cu2O and Ag@Cu core-shell NPs with fixed core size but varying outer shell thicknesses could be obtained. The composites, structures, morphologies and extinction properties of Ag@Cu2O and Ag@Cu core-shell NPs were systematically characterized by XRD, TEM and extinction spectra. Both of these NPs show wide tunable optical properties. The extinction peaks could be shifted from 421 nm to 700 nm. FTIR results reveal that Cu+ ions on the surface of Cu2 O nanocrystalline coordinate with N and O atoms in PVP and further are reduced to metallic Cu by excessive ascorbic acid and then form a nucleation site on the surface of Cu2 O nanocrystalline. PVP binds onto a different site to proceed with the reduction until all the Cu sources in Cu2 O NPs are completely assumed. And the shell of Cu2 O is converted to Cu shell. The synthesis approach in this paper is simple and also a promising reference for synthesizing other core-shell NPs. Ag@Cu2O NPs can be easily converted to Ag@Cu NPs in air at room temperature, which is promising to be used in electronic devices.

The Current Status, Problems and Prospects of Researches on the Carrying Capacities of Ecological Environment in China

Determining the carrying capacity of ecological resources is the key to finding contradictions between human activities and the environment,as well as the links between economic growth,environmental protection and social development.In recent years,the carrying capacity of the ecological environment has been extensively studied at home and abroad.Through extensive literature research and analysis,this paper discusses the current status and main problems of recent research on the carrying capacity of the ecological environment in China.For example,two of the main problems are that:1)the concepts and connotations are not clear enough,and 2)the research content is not systematic enough.This is followed by a summary of the evaluation index system and main calculation methods.Finally,according to the research status and development trends at home and abroad,the possible direction for the development of this research field in the future is proposed.