潜在语义分析权重计算的改进

自从潜在语义分析方法诞生以来,被广泛应用于信息检索、文本分类、自动问答系统等领域中。潜在语义分析的一个重要过程是对词语文档矩阵作加权转换,加权函数直接影响潜在语义分析结果的优劣。本文首先总结了传统的、已成熟的权重计算方法,包括局部权重部分和词语全局权重部分,随后指出已有方法的不足之处,并对权重计算方法进行扩展,提出文档全局权重的概念。在最后的实验中,提出了一种新的检验潜在语义分析结果优劣的方法———文档自检索矩阵,实验结果证明改进后的权重计算方法提高了检索效率。

Optimal replacement policy of products with repair-cost threshold after the extended warranty

The reliability of the product sold under a warranty is usually maintained by the manufacturer during the warranty period. After the expiry of the warranty, however, the consumer confronts a problem about how to maintain the reliability of the product. This paper proposes, from the consumer's perspective, a replacement policy after the extended warranty, under the assumption that the product is sold under the renewable free replacement warranty (RFRW) policy in which the replacement is dependent on the repair-cost threshold. The proposed replacement policy is the replacement after the extended warranty is performed by the consumer based on the repair-cost threshold or preventive replacement (PR) age, which are decision variables. The expected cost rate model is derived from the consumer's perspective. The existence and uniqueness of the optimal solution that minimizes the expected cost rate per unit time are offered. Finally, a numerical example is presented to exemplify the proposed model.

Integrated importance measure for multi-state coherent systems of k level

To verify the effectiveness of the integrated importance measure （IIM） for multi-state coherent systems of k level, the definition and physical meaning of IIM are demonstrated. Then, the improvement potential and Δ-importance measures are generalized to multi-state coherent systems based on the system performance level, and the relationships between IIM and traditional importance measures are discussed. The characteristics of IIM are demonstrated in both series and parallel systems. Also, an application to an oil transportation system is given. The comparison results show that： （i） IIM has some useful properties that are not possessed by traditional importance measures; （ii） IIM is effective in evaluating the component role in multi-state systems when the component reliability and the failure rate are simultaneously considered.

Learning Bayesian network structure with immune algorithm

Finding out reasonable structures from bulky data is one of the difficulties in modeling of Bayesian network （BN）, which is also necessary in promoting the application of BN. This pa- per proposes an immune algorithm based method （BN-IA） for the learning of the BN structure with the idea of vaccination. Further- more, the methods on how to extract the effective vaccines from local optimal structure and root nodes are also described in details. Finally, the simulation studies are implemented with the helicopter convertor BN model and the car start BN model. The comparison results show that the proposed vaccines and the BN-IA can learn the BN structure effectively and efficiently.

Bag-1蛋白表达与胃癌临床病理因素关系的研究(英文)

Objective:The aim of our study was to investigate Bcl-2 antanogene-1 (Bag-1) expressions in gastric cancer and evaluate their clinical significance.Methods:Bag-1 expressions were studied by the immunohistochemical streptavidinperosidase (S-P) method in 62 samples of gastric cancer tissues,11 normal gastric tissues,and their clinical significance was analyzed.Results:The positive rate of Bag-1 expression in the gastric carcinoma tissues was 41.94% (26/62),while it was 9.09% (1/11) in the normal gastric tissues (P=0.046).Though Bag-1 was positively related to the tumour pathological grade,lymph node metastasis and prognosis (P<0.05),it was not related to the sex,age,location,tumour diameter,depth of invasion (P>0.05).Conclusion:There are over expression of Bag-1 gene protein in gastric cancer,it is significance in prognosis of gastric cancer.

与早期胃癌复发有关的临床病理特性及生物指标的分析(英文)

Objective: The aim of this study was to identify the correlation between the clinicopathological characteristics and recurrence in early gastric cancer (EGC), what's more, we attempt to look for a predictive biomarker to predict and treat for re-currence of EGC. Methods: This study retrospectively analyzed 178 early gastric cancer patients who had the complete post-operative and follow-up medical records in the First Affiliated Hospital of Yangtze University (China) between January 1995 to December 2005. All of them were followed-up to December 2009 regularly. Computer tomography (CT), endoscopy, and single photon emission computed tomography (SPET-CT) were used to diagnose for recurrence of EGC. Immunohistochem-istry (IHC) and fluorescence in situ hybridization (FISH) were used for the detection of cerbB2. Chi-square test was applied to this study for statistics analysis. Results: Fourteen patients had recurrence. Eighteen patients were cerbB2-positive, including twelve recurrence patients and six norecurrence patients. Sex, tumor depth, and lymph node metastasis were related to the recurrence of EGC. Also, cerbB2-positive patients had the higher recurrence rate compared to the cerbB2-negative patients. Conclusion: Recurrence of EGC after curative resection can be predicted by using some clinicopathological characteristics. CerbB2 can be used as a predictive biomarker for recurrence of EGC.

Transference Kinetics of Radionuclide ⁹⁵Nb in the Aquatic Ecosystem

The dynamics of transportation, accumulation, diminishment and distribution of 95Nb in a simulated aquatic ecosystem was studied using the isotope-tracer technique, and a fitting equation was established by application of a closed, five-compartment model. The results showed that when 95Nb was introduced into an aquatic system, it was transported and transformed via deposition in combination with other ions, and adsorption and absorption by aquatic organisms, resulting in redistribution and accumulation in different parts of the organisms. Following addition, the spe- cific activity of 95Nb in water decreased sharply within a short time, and then after reaching a certain value, it decreased more slowly. Sediment accumulated large amounts of 95Nb through the exchange of ions. Hyacinth (Eichhornia crassipes) also adsorbed a large amount of 95Nb in a short period of time. Snails (Bellamya purificata) and fish (Carassius auratus) were found to have a poor adsorption capacity of 95Nb. The amount of 95Nb found in the snail flesh was greater than that in the shell, and the 95Nb found in the fish was mainly distributed in the viscera. The amount of 95Nb in each individual component of the experimental system was affected over time.

Recent advances in system reliability optimization driven by importance measures

System reliability optimization problems have been widely discussed to maximize system reliability with resource constraints.Bimbaum importance is a wellknown method for evaluating the effect of component reliability on system reliability.Many importance measures(IMs)are extended for binary,multistate,and continuous systems from different aspects based on the Bimbaum importance.Recently,these IMs have been applied in allocating limited resources to the component to maximize system performance.Therefore,the significance of Bimbaum importance is illustrated from the perspective of probability principle and gradient geometrical sense.Furthermore,the equations of various extended IMs are provided subsequently.The rules for simple optimization problems are summarized to enhance system reliability by using ranking or heuristic methods based on IMs.The importance-based optimization algorithms for complex or large-scale systems are generalized to obtain remarkable solutions by using IM-based local search or simplification methods.Furthermore,a general framework driven by IM is developed to solve optimization problems.Finally,some challenges in system reliability optimization that need to be solved in the future are presented.

Leaf metabolic influence of glyphosate and nanotubes on the Arabidopsis thaliana phyllosphere

Chemical exposure can indirectly affect leaf microbiota communities,but the mechanism driving this phenomenon remains largely unknown.Results revealed that the co-exposure of glyphosate and multi-carbon nanotubes(CNTs)caused a synergistic inhibitory effect on the growth and metabolism of Arabidopsis thaliana shoots.However,only a slight inhibitory effect was induced by nanotubes or glyphosate alone at the tested concentrations.Several intermediate metabolites of nitrogen metabolism and fatty acid synthesis pathways were upregulated under the combined treatment,which increased the amount of energy required to alleviate the disruption caused by the combined treatment.Additionally,compared with the two individual treatments,the glyphosate/nanotube combination treatment induced greater fluctuations in the phyllosphere bacterial community members with low abundance(relative abundance(RA)<1%)at both the family and genus levels,and among these bacteria some plant growth promotion and nutrient supplement related bacteria were markable increased.Strikingly,strong correlations between phyllosphere bacterial diversity and metabolites suggested a potential role of leaf metabolism,particularly nitrogen and carbohydrate metabolism,in restricting the range of leaf microbial taxa.These correlations between phyllosphere bacterial diversity and leaf metabolism will improve our understanding of plant-microbe interactions and the extent of their drivers of variation and the underlying causes of variability in bacterial community composition.