Designed and built by eight Dutch engineers,the worlds longest bicycle is 55.16 meters,roughly the same length as four double-decker buses.39-year-old Ivan Schalk had been thinking about building the world's longe...Designed and built by eight Dutch engineers,the worlds longest bicycle is 55.16 meters,roughly the same length as four double-decker buses.39-year-old Ivan Schalk had been thinking about building the world's longest bicycle since reading about it in The Guinness Book of Records when he was a child,but he only started this project in 2018,as a way to fill up his free time.展开更多
China completed the construction of the world's longest expressway tunnel through snow⁃covered mountains in the Xinjiang Uygur Autonomous Region,marking a significant milestone in its infrastructure development.On...China completed the construction of the world's longest expressway tunnel through snow⁃covered mountains in the Xinjiang Uygur Autonomous Region,marking a significant milestone in its infrastructure development.Once operational,the 22.13⁃km Tianshan Shengli Tunnel will reduce the travel time through the Tianshan Mountains-one of the longest mountain ranges in the world-from 3 hours to about 20 minutes.展开更多
We say that a parameter p of directed graphs has the interval property if for every graph G?and orientations of G, p can take every value between its minimum and maximum values. Let λbe the length of the lo...We say that a parameter p of directed graphs has the interval property if for every graph G?and orientations of G, p can take every value between its minimum and maximum values. Let λbe the length of the longest directed path. A question asked by C. Lin in [1] is equivalent to the question of whether λhas the interval property. In this note, we answer this question in the affirmative. We also show that the diameter of directed graphs does not have the interval property.展开更多
[Objective] The aim was to study the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years. [Method] Based on the data of longest continuous rainfall days in Shenyang from May to...[Objective] The aim was to study the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years. [Method] Based on the data of longest continuous rainfall days in Shenyang from May to September in 1961-2008, the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years was analyzed by means of one-dimensional linear trend estimation and wavelet analysis method. [Result] In recent 48 years, the longest continuous rainfall days in Shenyang showed decrease trend from May to September except for June in which it showed increased; the total longest continuous rainfall days showed decrease trend, and the maximum value appeared in 1986, while the minimum value could be found in 1997; from periodic variation, the total longest continuous rainfall days had the period of 2-3 years, and there also existed the period of 5-7 years after 1980; the total longest continuous rainfall days were more from the beginning of 1960s to the middle of 1990s and less thereafter. [Conclusion] The study could provide theoretical foundation for the deep research on climate change in Shenyang.展开更多
A graph is called claw-free if it does not contain a claw as its induced subgraph.In this paper, we prove the following results:1)If G is a 2-connected claw-free graph on n vertices,then for any vertex v and any two d...A graph is called claw-free if it does not contain a claw as its induced subgraph.In this paper, we prove the following results:1)If G is a 2-connected claw-free graph on n vertices,then for any vertex v and any two distinct vertices x and y in V(G)-{v},G has a path containing v and all neighbors of v and connecting x and y;2) Let C be the longest cycle in a 3-connected claw-free graph G and H a component of G-C,and if H is connected but not 2-connected,then there exist nonadjacent vertices u and v in H such that |V(C)|≥(3(d(u)+)d(v))-2.展开更多
Zongza Lhagyicannot forgetDecember 3,1999,When hereceived the entry certifi-cate from me London-based Guinness Book ofWorld Records while hewas in Shanghai.It reads:China Tibetan Cultural ArtColor Painting, the longes...Zongza Lhagyicannot forgetDecember 3,1999,When hereceived the entry certifi-cate from me London-based Guinness Book ofWorld Records while hewas in Shanghai.It reads:China Tibetan Cultural ArtColor Painting, the longest.measures 618 meters longand 2.3 meters wide.展开更多
A graph G is{K_(1,4),K_(1,4)+e}-free if G contains no induced subgraph isomorphic to K_(1,4) or KI,a+e In this paper,we show that G has a path which is either hamiltonian or of length at least 25(G)+2 if G is a connec...A graph G is{K_(1,4),K_(1,4)+e}-free if G contains no induced subgraph isomorphic to K_(1,4) or KI,a+e In this paper,we show that G has a path which is either hamiltonian or of length at least 25(G)+2 if G is a connected{K_(1,4),K_(1,4)+e}-free graph on at least 7 vertices.展开更多
M. Matthews and D. Sumner proved that if G is a 2-connected claw-free graph of order n, then c(G) min{2δb + 4, n}. In this paper, we prove that if G is a,2-connected claw-free graph on n venices, then c(G) min{3δ + ...M. Matthews and D. Sumner proved that if G is a 2-connected claw-free graph of order n, then c(G) min{2δb + 4, n}. In this paper, we prove that if G is a,2-connected claw-free graph on n venices, then c(G) min{3δ + 2, n} or G belongs to one exceptional class of graphs.展开更多
This paper discusses the asymptotic behaviors of the longest run on a countable state Markov chain. Let {Xa}a∈Z＋ be a stationary strongly ergodic reversible Markov chain on countable- state space S = {1, 2,...}. Let...This paper discusses the asymptotic behaviors of the longest run on a countable state Markov chain. Let {Xa}a∈Z＋ be a stationary strongly ergodic reversible Markov chain on countable- state space S = {1, 2,...}. Let T C S be an arbitrary finite subset of S. Denote by Ln the length of the longest run of consecutive i＇s for i E T, that occurs in the sequence X1,..., Xn. In this paper, we obtain a limit law and a week version of an Erd6s Rdnyi type law for Ln. A large deviation result of Ln is also discussed.展开更多
Let X1,X2,…,Xn,…be a sequence of i.i.d.random variables uniformly distributed on[0;1],and denote by Ln the length of the longest increasing subsequences of X1,X2,…,Xn.Consider the poissonized version Hn based on Ha...Let X1,X2,…,Xn,…be a sequence of i.i.d.random variables uniformly distributed on[0;1],and denote by Ln the length of the longest increasing subsequences of X1,X2,…,Xn.Consider the poissonized version Hn based on Hammersley’s representation in the 2-dimensional space.A law of the iterated logarithm for Hn is established using the well-known subsequence method and Borel-Cantelli lemma.The key technical ingredients in the argument include superadditivity,increment independence and precise tail estimates for the Hn’s.The work was motivated by recent works due to Ledoux(J.Theoret.Probab.31,(2018)).It remains open to establish an analog for the Ln itself.展开更多
In this paper we mainly discuss lower and upper bounds for the length of longest consecutive switches inⅡD Bernoulli sequences.This work is an extension of results for longest consecutive switches in unbiased coin-to...In this paper we mainly discuss lower and upper bounds for the length of longest consecutive switches inⅡD Bernoulli sequences.This work is an extension of results for longest consecutive switches in unbiased coin-tossing,and might be applied to reliability theory,biology,quality control,pattern recognition,finance,etc.展开更多
世界卫生组织6月4日公布了该组织对191个成员国居民健康寿命的预测和排名顺序。这次排名不同以往,采取了Disability Adjusted Life Expectancy的方法,本文将它简化为DALE,所谓DALE就是预测出的健康寿命已减去居民一生中可能罹患疾病的...世界卫生组织6月4日公布了该组织对191个成员国居民健康寿命的预测和排名顺序。这次排名不同以往,采取了Disability Adjusted Life Expectancy的方法,本文将它简化为DALE,所谓DALE就是预测出的健康寿命已减去居民一生中可能罹患疾病的时间。 日本居民平均健康生活的时间74.5年,位居第一。澳大利亚排名第二:73.2岁;法国第三:73.1岁;美国排名第二十四:68.4岁;中国排第81位:男61.2,女62.3。在发展中国家位居前列。俄罗斯第91位,印度第134位。 以上所列系一个国家的平均水平,但是,在一国之内,居民平均健康生活的时间并不平均。笔者在东方网上录下了以下数据:展开更多
最长公共子序列(longest common subsequence,LCS)是一种衡量代码相似度的可行指标.然而,经典LCS算法的时间复杂度较高,难以应对大型数据集,并且,由于代码文本序列中的词(token)本质为一种基于离散表示的编码,直接使用LCS算法无法有效...最长公共子序列(longest common subsequence,LCS)是一种衡量代码相似度的可行指标.然而,经典LCS算法的时间复杂度较高,难以应对大型数据集,并且,由于代码文本序列中的词(token)本质为一种基于离散表示的编码,直接使用LCS算法无法有效识别文本不同但语义相似的代码片段中的关键语义.针对这两方面的不足,提出一种面向LCS的嵌入方法,将代码间的LCS计算转换为代码低维稠密嵌入向量间的数值运算,并可以利用近似最近邻算法进一步加速其计算.为此,设计了一个可嵌入的基于LCS的距离度量方法,实验证明这种代码度量在提取函数关键语义的表现上优于对比嵌入工具使用的基于文本的距离或基于树的距离.同时,为了在嵌入过程中有重点地保留代码的关键语义,构建了两种损失函数和相应的训练集,识别文本上不同但语义上相似的代码元素,使模型在检测复杂代码克隆时有更好的表现.实验证明了该方法拥有很强的可扩展性,且其对复杂克隆的检测能力也保持在很高水平.将该技术应用于相似缺陷的识别,上报了23个未知缺陷,这些缺陷已被开发人员在实际项目中确认,其中有些复杂缺陷是难以被基于文本的LCS算法检出的.展开更多
文摘Designed and built by eight Dutch engineers,the worlds longest bicycle is 55.16 meters,roughly the same length as four double-decker buses.39-year-old Ivan Schalk had been thinking about building the world's longest bicycle since reading about it in The Guinness Book of Records when he was a child,but he only started this project in 2018,as a way to fill up his free time.
文摘China completed the construction of the world's longest expressway tunnel through snow⁃covered mountains in the Xinjiang Uygur Autonomous Region,marking a significant milestone in its infrastructure development.Once operational,the 22.13⁃km Tianshan Shengli Tunnel will reduce the travel time through the Tianshan Mountains-one of the longest mountain ranges in the world-from 3 hours to about 20 minutes.
文摘We say that a parameter p of directed graphs has the interval property if for every graph G?and orientations of G, p can take every value between its minimum and maximum values. Let λbe the length of the longest directed path. A question asked by C. Lin in [1] is equivalent to the question of whether λhas the interval property. In this note, we answer this question in the affirmative. We also show that the diameter of directed graphs does not have the interval property.
文摘[Objective] The aim was to study the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years. [Method] Based on the data of longest continuous rainfall days in Shenyang from May to September in 1961-2008, the variation characteristics of longest continuous rainfall days in Shenyang in recent 48 years was analyzed by means of one-dimensional linear trend estimation and wavelet analysis method. [Result] In recent 48 years, the longest continuous rainfall days in Shenyang showed decrease trend from May to September except for June in which it showed increased; the total longest continuous rainfall days showed decrease trend, and the maximum value appeared in 1986, while the minimum value could be found in 1997; from periodic variation, the total longest continuous rainfall days had the period of 2-3 years, and there also existed the period of 5-7 years after 1980; the total longest continuous rainfall days were more from the beginning of 1960s to the middle of 1990s and less thereafter. [Conclusion] The study could provide theoretical foundation for the deep research on climate change in Shenyang.
文摘A graph is called claw-free if it does not contain a claw as its induced subgraph.In this paper, we prove the following results:1)If G is a 2-connected claw-free graph on n vertices,then for any vertex v and any two distinct vertices x and y in V(G)-{v},G has a path containing v and all neighbors of v and connecting x and y;2) Let C be the longest cycle in a 3-connected claw-free graph G and H a component of G-C,and if H is connected but not 2-connected,then there exist nonadjacent vertices u and v in H such that |V(C)|≥(3(d(u)+)d(v))-2.
文摘Zongza Lhagyicannot forgetDecember 3,1999,When hereceived the entry certifi-cate from me London-based Guinness Book ofWorld Records while hewas in Shanghai.It reads:China Tibetan Cultural ArtColor Painting, the longest.measures 618 meters longand 2.3 meters wide.
基金Supported by Scientific Research Program of the Higher Education Institution of Xinjiang(Grant No.2011S30)Science Foundation of Xinjiang Normal University
文摘A graph G is{K_(1,4),K_(1,4)+e}-free if G contains no induced subgraph isomorphic to K_(1,4) or KI,a+e In this paper,we show that G has a path which is either hamiltonian or of length at least 25(G)+2 if G is a connected{K_(1,4),K_(1,4)+e}-free graph on at least 7 vertices.
文摘M. Matthews and D. Sumner proved that if G is a 2-connected claw-free graph of order n, then c(G) min{2δb + 4, n}. In this paper, we prove that if G is a,2-connected claw-free graph on n venices, then c(G) min{3δ + 2, n} or G belongs to one exceptional class of graphs.
文摘This paper discusses the asymptotic behaviors of the longest run on a countable state Markov chain. Let {Xa}a∈Z＋ be a stationary strongly ergodic reversible Markov chain on countable- state space S = {1, 2,...}. Let T C S be an arbitrary finite subset of S. Denote by Ln the length of the longest run of consecutive i＇s for i E T, that occurs in the sequence X1,..., Xn. In this paper, we obtain a limit law and a week version of an Erd6s Rdnyi type law for Ln. A large deviation result of Ln is also discussed.
基金supported by the National Natural Science Foundation of China(Nos.11871425,11731012)the Fundamental Research Funds for Central Universities.
文摘Let X1,X2,…,Xn,…be a sequence of i.i.d.random variables uniformly distributed on[0;1],and denote by Ln the length of the longest increasing subsequences of X1,X2,…,Xn.Consider the poissonized version Hn based on Hammersley’s representation in the 2-dimensional space.A law of the iterated logarithm for Hn is established using the well-known subsequence method and Borel-Cantelli lemma.The key technical ingredients in the argument include superadditivity,increment independence and precise tail estimates for the Hn’s.The work was motivated by recent works due to Ledoux(J.Theoret.Probab.31,(2018)).It remains open to establish an analog for the Ln itself.
基金Supported by the National National Science Foundation of China(Grant Nos.12101429,12171335)the Science Development Project of Sichuan University(Grant No.2020SCUNL201)the Fundamental Research Funds for the Central Universities of China。
文摘In this paper we mainly discuss lower and upper bounds for the length of longest consecutive switches inⅡD Bernoulli sequences.This work is an extension of results for longest consecutive switches in unbiased coin-tossing,and might be applied to reliability theory,biology,quality control,pattern recognition,finance,etc.
文摘最长公共子序列(longest common subsequence,LCS)是一种衡量代码相似度的可行指标.然而,经典LCS算法的时间复杂度较高,难以应对大型数据集,并且,由于代码文本序列中的词(token)本质为一种基于离散表示的编码,直接使用LCS算法无法有效识别文本不同但语义相似的代码片段中的关键语义.针对这两方面的不足,提出一种面向LCS的嵌入方法,将代码间的LCS计算转换为代码低维稠密嵌入向量间的数值运算,并可以利用近似最近邻算法进一步加速其计算.为此,设计了一个可嵌入的基于LCS的距离度量方法,实验证明这种代码度量在提取函数关键语义的表现上优于对比嵌入工具使用的基于文本的距离或基于树的距离.同时,为了在嵌入过程中有重点地保留代码的关键语义,构建了两种损失函数和相应的训练集,识别文本上不同但语义上相似的代码元素,使模型在检测复杂代码克隆时有更好的表现.实验证明了该方法拥有很强的可扩展性,且其对复杂克隆的检测能力也保持在很高水平.将该技术应用于相似缺陷的识别,上报了23个未知缺陷,这些缺陷已被开发人员在实际项目中确认,其中有些复杂缺陷是难以被基于文本的LCS算法检出的.
