40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039)最新文献

A probabilistic algorithm for k-SAT and constraint satisfaction problems k-SAT和约束满足问题的概率算法

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814612

U. Schöning

{"title":"A probabilistic algorithm for k-SAT and constraint satisfaction problems","authors":"U. Schöning","doi":"10.1109/SFFCS.1999.814612","DOIUrl":"https://doi.org/10.1109/SFFCS.1999.814612","url":null,"abstract":"We present a simple probabilistic algorithm for solving k-SAT and more generally, for solving constraint satisfaction problems (CSP). The algorithm follows a simple local search paradigm (S. Minton et al., 1992): randomly guess an initial assignment and then, guided by those clauses (constraints) that are not satisfied, by successively choosing a random literal from such a clause and flipping the corresponding bit, try to find a satisfying assignment. If no satisfying assignment is found after O(n) steps, start over again. Our analysis shows that for any satisfiable k-CNF-formula with n variables this process has to be repeated only t times, on the average, to find a satisfying assignment, where t is within a polynomial factor of (2(1-1/k))/sup n/. This is the fastest (and also the simplest) algorithm for 3-SAT known up to date. We consider also the more general case of a CSP with n variables, each variable taking at most d values, and constraints of order l, and analyze the complexity of the corresponding (generalized) algorith m. It turns out that any CSP can be solved with complexity at most (d/spl middot/(1-1/l)+/spl epsiv/)/sup n/.","PeriodicalId":385047,"journal":{"name":"40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127228932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 470

Satisfiability of word equations with constants is in PSPACE 带常数的词方程在PSPACE中是可满足的

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814622

Wojciech Plandowski

引用次数: 212

Online scheduling to minimize average stretch 在线调度以最小化平均拉伸

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814615

S. Muthukrishnan, R. Rajaraman, Anthony Shaheen, J. Gehrke

{"title":"Online scheduling to minimize average stretch","authors":"S. Muthukrishnan, R. Rajaraman, Anthony Shaheen, J. Gehrke","doi":"10.1109/SFFCS.1999.814615","DOIUrl":"https://doi.org/10.1109/SFFCS.1999.814615","url":null,"abstract":"We consider the classical problem of online job scheduling on uniprocessor and multiprocessor machines. For a given job, we measure the quality of service provided by an algorithm by the stretch of the job, which is defined as the ratio of the amount of time that the job spends in the system to the processing time of the job. For a given sequence of jobs, we measure the performance of an algorithm by the average stretch achieved by the algorithm over all the jobs in the sequence. The average stretch metric has been used to evaluate the performance of scheduling algorithms in many applications arising in databases, networks and systems; however no formal analysis of scheduling algorithms is known for the average stretch metric. The main contribution of the paper is to show that the shortest remaining processing time algorithm (SRPT) is O(l)-competitive with respect to average stretch for both uniprocessors as well as multiprocessors. For uniprocessors, we prove that SRPT is 2-competitive; we also establish an essentially matching lower bound on the competitive ratio of SRPT. For multiprocessors, we show that the competitive ratio of SRPT is at most 14. Furthermore, we establish constant-factor lower bounds on the competitive ratio of any online algorithm for both uniprocessors and multiprocessors.","PeriodicalId":385047,"journal":{"name":"40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115836986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 128

Approximation schemes for minimizing average weighted completion time with release dates 最小化平均加权完成时间与发布日期的近似方案

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814574

F. Afrati, E. Bampis, C. Chekuri, David R Karger, Claire Mathieu, S. Khanna, I. Milis, M. Queyranne, M. Skutella, C. Stein, M. Sviridenko

引用次数: 214

Boosting and hard-core sets 增强和硬核设置

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814638

Adam R. Klivans, R. Servedio

{"title":"Boosting and hard-core sets","authors":"Adam R. Klivans, R. Servedio","doi":"10.1109/SFFCS.1999.814638","DOIUrl":"https://doi.org/10.1109/SFFCS.1999.814638","url":null,"abstract":"This paper connects two fundamental ideas from theoretical computer science hard-core set construction, a type of hardness amplification from computational complexity, and boosting, a technique from computational learning theory. Using this connection we give fruitful applications of complexity-theoretic techniques to learning theory and vice versa. We show that the hard-core set construction of R. Impagliazzo (1995), which establishes the existence of distributions under which boolean functions are highly inapproximable, may be viewed as a boosting algorithm. Using alternate boosting methods we give an improved bound for hard-core set construction which matches known lower bounds from boosting and thus is optimal within this class of techniques. We then show how to apply techniques from R. Impagliazzo to give a new version of Jackson's celebrated Harmonic Sieve algorithm for learning DNF formulae under the uniform distribution using membership queries. Our new version has a significant asymptotic improvement in running time. Critical to our arguments is a careful analysis of the distributions which are employed in both boosting and hard-core set constructions.","PeriodicalId":385047,"journal":{"name":"40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133493833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 51

Approximating fractional multicommodity flow independent of the number of commodities 近似于独立于商品数量的分数多商品流

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814573

L. Fleischer

引用次数: 357

Torpid mixing of some Monte Carlo Markov chain algorithms in statistical physics 统计物理中一些蒙特卡罗马尔可夫链算法的迟钝混合

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814594

C. Borgs, J. Chayes, A. Frieze, J. Kim, P. Tetali, Eric Vigoda, Van H. Vu

引用次数: 108

Dynamic planar convex hull operations in near-logarithmic amortized time 近对数平摊时间的动态平面凸壳运算

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814581

Timothy M. Chan

引用次数: 106

Error reduction for extractors 减少提取器的错误

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814591

R. Raz, Omer Reingold, S. Vadhan

{"title":"Error reduction for extractors","authors":"R. Raz, Omer Reingold, S. Vadhan","doi":"10.1109/SFFCS.1999.814591","DOIUrl":"https://doi.org/10.1109/SFFCS.1999.814591","url":null,"abstract":"An extractor is a function which extracts (almost) truly random bits from a weak random source, using a small number of additional random bits as a catalyst. We present a general method to reduce the error of any extractor. Our method works particularly well in the case that the original extractor extracts up to a constant function of the source min-entropy and achieves a polynomially small error. In that case, we are able to reduce the error to (almost) any /spl epsiv/, using only O(log(1//spl epsiv/)) additional truly random bits (while keeping the other parameters of the original extractor more or less the same). In other cases (e.g. when the original extractor extracts all the min-entropy or achieves only a constant error), our method is not optimal but it is still quite efficient and leads to improved constructions of extractors. Using our method, we are able to improve almost all known extractors in the case where the error required is relatively small (e.g. less than a polynomially small error). In particular, we apply our method to the new extractors of L. Trevisan (1999) and R. Raz et al. (1999) to obtain improved constructions in almost all cases. Specifically, we obtain extractors that work for sources of any min-entropy on strings of length n which (a) extract any 1/n/sup /spl gamma// fraction of the min-entropy using O[log n+log(1//spl epsiv/)] truly random bits (for any /spl gamma/>0), (b) extract any constant fraction of the min-entropy using O[log/sup 2/n+log(1//spl epsiv/)] truly random bits, and (c) extract all the min-entropy using O[log/sup 3/n+log n/spl middot/log(1//spl epsiv/)] truly random bits.","PeriodicalId":385047,"journal":{"name":"40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130065889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 48

Weak adversaries for the k-server problem k-server问题的弱对手

40th Annual Symposium on Foundations of Computer Science (Cat. No.99CB37039) Pub Date : 1999-10-17 DOI: 10.1109/SFFCS.1999.814616

E. Koutsoupias

引用次数: 38