检索结果-南通市图书馆

Feasibility study on the dfp adoption of medical cyclotron decommissioning in the Republic of Korea

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2014年第A1期25卷 11-14页

作者： Rina Woo Minchul Song Daehyung Cho Wantae Kim Yongmin Kim Department of Radiological Science Catholic University of Daegu Gyeongsangbuk-do 712-702 Republic of Korea Korea Institute of Nuclear Safety Daejeon 305-338 Republic of Korea

Since the development of positron emission tomography in 1937, the number of medical cyclotrons used in producing radioisotopes (RI) has risen sharply. In its operation, the structural materials of a medical cyclotron and the concrete shielding of its vault are activated by neutrons. In analyzing domestic and international decommissioning practices, the dismantling characteristics of medical cyclotrons result in a large amount of radioactive wastes, such as concrete, although their activity level is very low. In the United States, the dismantling plan must be established by the applicant. The decommissioning funding plan (dfp) is a financial assurance demonstration based on a site-specific cost estimate of decommissioning the facility. In 10 CFR 30.35, NRC requires the submission of dfp in the case of the possession and use of unsealed byproduct materials with a half-life of greater than 120 days and in quantities exceeding 105 times that of the applicable quantities. The dismantling of the Seoul National University Hospital (SNUH) cyclotron (TR-13) was performed in December 2012. Some of the risks resulting from this dismantling are related to radioactive wastes, as well as issues concerning dismantling costs. Hence, we propose introducing the dfp at the authorization stage. dfp will be helpful in preparing reliable decommissioning plans for safe decommissioning and unexpected early decommissioning in the future. dfp can also contribute in reducing radioactive waste and in decreasing the decommissioning cost by preventing excessive establishments. This study provided an overview of the decommissioning aspects of the SNUH cyclotron and the necessity of adopting the dfp for decommissioning medical cyclotrons. © 2014, Science Press. All rights reserved.

关键词：医用回旋加速器退役计划 dfp 正电子发射断层扫描放射性废物混凝土屏蔽韩国放射性同位素

Convergence of dfp algorithm

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 1995年第11期38卷 1281-1294页

作者：袁亚湘 State Key Laboratory of Scientific and Engineering Computing ICMSEC Chinese Academy of Sciences Beijing 100080 China

The dfp method is one of the most famous numerical algorithms for unconstrained optimization. For uniformly convex objective functions convergence properties of the dfp method are studied. Several conditions that can ... 详细信息

关键词： global convergence dfp algorithm line search.

Global convergence of quasi-Newton methods for unconstrained optimization

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1996年第7期41卷 529-533页

作者：韩立兴刘光辉 Department of Mathematics and Institute of Applied Mathematics Tianjin University Tianjin 300072 China. Department of Industrial Engineering and Management Sciences Northwestern University Evanston IL 60208USA.

The convergence of quasi-Newton methods for unconstrained optimization has at-tracted much attention. Powell proved a global convergence result for the BFGS algorithmusing inexact linesearch which satisfies the Wolfe conditions. Byrd, Nocedal and Yuanextended this result to the convex Broyden class of quasi-Newton methods except the dfpmethod. However, the global convergence of the dfp method, the first quasi-Newtonmethod, using the same linesearch strategy, is still an open question (see ref. [2]).

关键词： quasi-Newton methods unconstrained optimization dfp algorithm global convergence.

SUPERLINEAR CONVERGENCE OF THE dfp ALGORITHM WITHOUT EXACT LINE SEARCH

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2001年第3期17卷 430-432页

作者：濮定国 Department of Mathematics Tongji University

Broyden algorithms are very efficient methods for solving the nonlinear programming problem: min {f(x); x ∈ Rn}. (1)With exact line search, Powell[1] proved that the rate of convergence of these algorithms is one-step Q-superlinear for a twice continuously differentiable and uniformly convex function,and pu[2] extended this result for LC1 function. Pu and Yu[3] proved that if the points which are given by these algorithms are convergent they are globally convergent for continuously differentiable functions without convexity.

关键词： dfp line SUPERLINEAR CONVERGENCE OF THE dfp ALGORITHM WITHOUT EXACT LINE SEARCH

在线全文

学校读者我要写书评

暂无评论

液态合金有效热扩散率dfp反算方法

铸造 2002年第8期51卷 477-480页

作者：李晓桥朱丽娟赵志立梁迪沈阳大学机械工程学院辽宁沈阳110041

以铝合金熔液为例进行液态合金有效热扩散率的测试和计算方法研究。采用数值计算和dfp优化技术 ,通过对待测液态合金有效热扩散率的优化计算使铸件凝固温度场计算结果与实测温度场趋于一致 ,最终获得该合金液的有效热扩散率随温度变化... 详细信息

以铝合金熔液为例进行液态合金有效热扩散率的测试和计算方法研究。采用数值计算和dfp优化技术 ,通过对待测液态合金有效热扩散率的优化计算使铸件凝固温度场计算结果与实测温度场趋于一致 ,最终获得该合金液的有效热扩散率随温度变化的规律。

关键词：液态合金有效热扩散率优化反算法 dfp 铝合金铸造

A　NEW　SUFFICIENT　CONDITION　FOR　THE　CONVERGENCE　OF　THE　dfp　ALGORITHM　WITH　WOLFE　LINE　SEARCH

在线全文

学校读者我要写书评

暂无评论

Systems Science and Mathematical Sciences 1996年第3期9卷 259-269页

作者： XU Dachuan(Department of Mathematics,Qufu Normal University,Qufu 273165,China)LIU Guanghui(Institute of Applied Mathematics, Academia Sinica, Beijing 100080,China) 曲阜师范大学数学系山东曲阜 273165 中科院应用数学所北京

ＡＮＥＷＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＦＯＲＴＨＥＣＯＮＶＥＲＧＥＮＣＥＯＦＴＨＥＤＦＰＡＬＧＯＲＩＴＨＭＷＩＴＨＷＯＬＦＥＬＩＮＥＳＥＡＲＣＨ￥ＸＵＤａｃｈｕａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉ... 详细信息

ＡＮＥＷＳＵＦＦＩＣＩＥＮＴＣＯＮＤＩＴＩＯＮＦＯＲＴＨＥＣＯＮＶＥＲＧＥＮＣＥＯＦＴＨＥＤＦＰＡＬＧＯＲＩＴＨＭＷＩＴＨＷＯＬＦＥＬＩＮＥＳＥＡＲＣＨ￥ＸＵＤａｃｈｕａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＱｕｆｕＮｏｒｍａｌＵｎｉｖ...

关键词： Global convergence dfp algorithm Wolfe line Search

在线全文

学校读者我要写书评

暂无评论

PLATES

Cell Research 1993年第2期 179-185页

PLATE I AChE-positive strucutres stained with Tago et al procedure in thespinal cord at the following ages: A) E14 cervical level; B) E15 thoracic level; C) El7 thoracic level; D) E18 cervical; level; E) E1... 详细信息

关键词： AChE PLATES dfp

基于dfp的自适应算法及其在短时交通流预测中的应用

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

西北工业大学学报 2013年第3期31卷 482-486页

作者：张玉梅曲仕茹秦小娜西北工业大学自动化学院陕西西安710072 陕西师范大学计算机科学学院陕西西安710062

研究了一种基于可变收敛因子的Davidon-Fletcher-Powell(dfp)自适应算法,给出算法中自相关逆矩阵估计的递归更新公式。对dfp算法中参数τ(n)的作用及算法的计算复杂度进行了分析。当分别输入正弦信号和高斯白噪声时,对不同滤波器阶数的... 详细信息

研究了一种基于可变收敛因子的Davidon-Fletcher-Powell(dfp)自适应算法,给出算法中自相关逆矩阵估计的递归更新公式。对dfp算法中参数τ(n)的作用及算法的计算复杂度进行了分析。当分别输入正弦信号和高斯白噪声时,对不同滤波器阶数的τ(n)随样例个数变化情况进行了仿真,并将dfp算法分别应用于3 min和5 min短时交通流预测。结果表明:τ(n)最终将趋于稳态值0.5,dfp算法能够较好地反映交通流量变化的趋势和规律,预测精度较高。

关键词：短时交通流预测 dfp 自适应滤波自相关逆矩阵

采用拟Newton法实现DOA及功率联合估计

在线全文

学校读者我要写书评

暂无评论

电子科技大学学报 2010年第2期39卷 173-175,181页

作者：何子远庞晓凤赵志钦电子科技大学电子工程学院成都610054

为了增加移动通信的容量和链接质量,需要准确地知道到达波的方向(DOA)和功率。该文提出了多维非线性目标函数,用来波DOA和功率作优化变量,并采用拟Newton法中常用的Davidson-Fletcher-Powell(dfp)算法进行优化;将优化结果和轮换投影(AP... 详细信息

为了增加移动通信的容量和链接质量,需要准确地知道到达波的方向(DOA)和功率。该文提出了多维非线性目标函数,用来波DOA和功率作优化变量,并采用拟Newton法中常用的Davidson-Fletcher-Powell(dfp)算法进行优化;将优化结果和轮换投影(AP)算法进行比较。仿真表明,当入射信号在空间相隔较远时,该结果和AP算法精度相当,当入射信号在空间接近时,该结果优于AP算法。

关键词： dfp DOA估计拟Newton法功率估计