一种高性能目标识别融合算法

考虑到目标类型数和传感器扫描次数对识别的影响，提出了一种改进的多传感器多目标识别相关算法，导出了新的累积融合公式。对多传感器多目标识别融合作了计算机模拟，模拟结果证实了改进的算法在性能上有明显的提高。     

过客：夕阳余晖下的彷徨

我在"教"中学,"研"中学,"撰"中学,作为现代文学的学习或研究者,至少应该在"阶梯四层次"、"三点连一线"之中有自己的"操作实践".在"古与今"、"中与外"、"雅与俗"和"传统方法和新方法"上有较为宽阔的"知识疆域".在科研选题上先得去作学术"勘探"和"考察",这种的选题才有广阔的开拓空间和一定的学术价值.在科研上我期望能完成"起家"、"转移"、"回归"的三部曲,这三部曲愿是一个"螺旋形上升"的过程.     

Combining Food Frequency and Survey Data to Quantify Long-Term Dietary Exposure: A Methyl Mercury Case Study

Twenty-four-hour recall data from the Continuing Survey of Food Intake by Individuals (CSFII) are frequently used to estimate dietary exposure for risk assessment. Food frequency questionnaires are traditional instruments of epidemiological research; however, their application in dietary exposure and risk assessment has been limited. This article presents a probabilistic method of bridging the National Health and Nutrition Examination Survey (NHANES) food frequency and the CSFII data to estimate longitudinal (usual) intake, using a case study of seafood mercury exposures for two population subgroups (females 16 to 49 years and children 1 to 5 years). Two hundred forty-nine CSFII food codes were mapped into 28 NHANES fish/shellfish categories. FDA and state/local seafood mercury data were used. A uniform distribution with minimum and maximum blood-diet ratios of 0.66 to 1.07 was assumed. A probabilistic assessment was conducted to estimate distributions of individual 30-day average daily fish/shellfish intakes, methyl mercury exposure, and blood levels. The upper percentile estimates of fish and shellfish intakes based on the 30-day daily averages were lower than those based on two- and three-day daily averages. These results support previous findings that distributions of "usual" intakes based on a small number of consumption days provide overestimates in the upper percentiles. About 10% of the females (16 to 49 years) and children (1 to 5 years) may be exposed to mercury levels above the EPA's RfD. The predicted 75th and 90th percentile blood mercury levels for the females in the 16-to-49-year group were similar to those reported by NHANES. The predicted 90th percentile blood mercury levels for children in the 1-to-5-year subgroup was similar to NHANES and the 75th percentile estimates were slightly above the NHANES.     

Estimating the fundamental frequency of a periodic function

In this paper we consider the problem of estimation of the fundamental frequency of a periodic function, which has several applications in Speech Signal Processing. The problem was originally proposed by Hannan (1974) and later on Quinn and Thomson (1991) provided an estimation procedure of the unknown parameters. It is observed that the estimation procedure of Quinn and Thomson (1991) is quite involved numerically. In this paper we propose to use two simple estimators and it is observed that their performance are quite satisfactory. Asymptotic properties of the proposed estimators are obtained. The large sample properties of the estimators are compared theoretically. We present some simulation results to compare their small sample performance. One speech data is analyzed using this particular model.     

时距估计干扰效应的研究与思考

已有的研究从不同作业类型下的干扰效应和相关的理论解释两个方面对时距估计干扰效应进行了剖析 ,未来的研究应以分段 /综合模型为基础进行探讨 ,时距加工的认知神经研究促进了人们对时间信息加工实质的理解。     

A Comparison of Gambling by Minnesota Public School Students in 1992, 1995, and 1998

The purpose of this study was to compare rates of gambling among Minnesota public school students between 1992, 1995, and 1998. The three samples included 75,806 students in the 9th and 12th grades in 1992; 73,897 9th and 12th grade students in 1995; and 78,564 9th and 12th grade students in 1998. Students were administered the Minnesota Student Survey, a 121-item, anonymous, self-administered, paper-and-pencil questionnaire that inquires about multiple behavioral domains, including gambling behaviors. The same questionnaire, with minor revisions to the gambling items, was administered in 1992, 1995, and 1998 to students in their classrooms by the Minnesota Department of Education. The results showed two opposite trends. On the one hand, fewer students gambled in 1998 than in 1995 and 1992. On the other hand, there was a small, but growing number of 12th grade students who gambled frequently. In terms of trends over time for specific games, the lottery showed a significant decline in the number of 9th grade students who played at all. There was also a significant increase in the number of 12th grade students who played the lottery weekly or more often. The findings that frequent lottery gambling has increased among 12th grade students and that underage gambling continues among these students, are both cause for concern. This is the first generation of youth to be exposed to widespread accessability to legalized gambling venues and gambling advertising. Legalized gambling may be a new "rite of passage" for some of today's youth. It will be important to continue to monitor youth gambling and to provide information and resources to assist youth in making healthy decisions about their gambling behavior.     

Kernel estimation of a distribution function

A distribution function is estimated by a kernel method with

a poinrwise mean squared error criterion at a point x. Relation- ships between the mean squared error, the point x, the sample size and the required kernel smoothing parazeter are investigated for several distributions treated by Azzaiini (1981). In particular it is noted that at a centre of symmetry or near a mode of the distribution the kernei method breaks down. Point- wise estimation of a distribution function is motivated as a more useful technique than a reference range for preliminary medical diagnosis.     

常见英语错误缘说

我国常见英语错误的发生率之高和涉及面之广已成为建设和谐社会的一道煞风景.本文通过对实际错误病例的列举并逐一对导致错误的缘由进行解说,兼辅以据出权威出版物的更正,以正视听.     

混流式水轮机转轮内部流场数值分析

从Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程出发，采用层流模型描述水流动状态，并在欧拉坐标系中用速度－压力修正法对模型进行求解，考虑到转轮内流道几何形状比较复杂，故采用有限元法进行数值离散，并将该解法用ＦＯＲＴＲＡＮ语言编制计算程序，对三峡工程混 式水轮机转轮内部的流场进行数值计算，分析了转轮内的速度和压力分布。     

Double Sampling Ratio-product Estimator of a Finite Population Mean in Sample Surveys

It is well known that two-phase (or double) sampling is of significant use in practice when the population parameter(s) (say, population mean X¯) of the auxiliary variate x is not known. Keeping this in view, we have suggested a class of ratio-product estimators in two-phase sampling with its properties. The asymptotically optimum estimators (AOEs) in the class are identified in two different cases with their variances. Conditions for the proposed estimator to be more efficient than the two-phase sampling ratio, product and mean per unit estimator are investigated. Comparison with single phase sampling is also discussed. An empirical study is carried out to demonstrate the efficiency of the suggested estimator over conventional estimators.