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22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)最新文献

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Relativizing time and space 将时间和空间相对化
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.39
R. V. Book, Christopher B. Wilson, Mei-rui Xu
{"title":"Relativizing time and space","authors":"R. V. Book, Christopher B. Wilson, Mei-rui Xu","doi":"10.1109/SFCS.1981.39","DOIUrl":"https://doi.org/10.1109/SFCS.1981.39","url":null,"abstract":"The problem of finding the precise relationship between computation time afldspa-ce is very important ·in complexity theory. Because this relationship remains unknown, there is an exponential discrepancy when upper and lower bounds are both expressed in tenns of time or space alone.· For example, not only is it not known whether a linear upper bound f~r space implies simultaneous upper bounds of linear space and polynomial time but also it is not known whether a linear upper bound for space implies a polynomial upper bound for time regardless of how much space is used. One method of approaching questions regarding the relationship between complexity classes is to study relativized complexity classes. One might attempt to prove that NP =PSPACE if and only if for every oracle set A, NP(A) = PSPACE\"(A); if one could prove this, then one could conclude that NP , PSPACE since it is known that there exists a set A such that NP(A), PSPACE{A) [2,.3,13], and knowing that NP ~ PSPACE would allow one to conclude that there exists a problem solvable in linear space but not solvable in polynomial time. However this equivalence has not been established. Different notions of controlled relativizations have been studied, on the one hand by controlling the resources bounding the query tape of","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131000131","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: 3
On relations between input and communication/computation in VLSI VLSI中输入与通信/计算的关系
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.26
Z. Kedem, A. Zorat
{"title":"On relations between input and communication/computation in VLSI","authors":"Z. Kedem, A. Zorat","doi":"10.1109/SFCS.1981.26","DOIUrl":"https://doi.org/10.1109/SFCS.1981.26","url":null,"abstract":"This extended abstract examines some of the fundamental issues involved. It is shown that when multiple copies of the inputs are allowed the standard methodology for deriving lower bounds on the complexity of VLSI chips is no longer applicable. A simple example is presented whose upper bound complexity with mUltiple copies of the inputs is below the lower bound complexity of that function when only a single copy of the inputs upper and lower bounds on such complexity for certain functions or families of functions. An important assumption made in the cited literature is that the inputs to the computations are made available to the chip only once. While this assumption is not of significance in the context of classical algorithm design for random access machines, it may carry important implications in the context of VLSI, where providing several copies of the inputs may be successfully employed to reduce the complexity of the computation. have is allowed. Finally, lower bounds on the complexity of a family of functions are derived for the case when multiple copies of the inputs are permitted.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115240760","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: 21
A minimum spanning ellipse algorithm 最小生成椭圆算法
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.7
Mark J. Post
{"title":"A minimum spanning ellipse algorithm","authors":"Mark J. Post","doi":"10.1109/SFCS.1981.7","DOIUrl":"https://doi.org/10.1109/SFCS.1981.7","url":null,"abstract":"An algorithm to find the minimum spanning ellipse of a convex set of points in the plane, i.e., the ellipse of minimum area containing the set, is described. The result for higher dimensions is suggested, along with a brief discussion of possible applications.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115655154","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: 14
The complexity of distributed concurrency control 分布式并发控制的复杂性
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1137/0214004
P. Kanellakis, C. Papadimitriou
{"title":"The complexity of distributed concurrency control","authors":"P. Kanellakis, C. Papadimitriou","doi":"10.1137/0214004","DOIUrl":"https://doi.org/10.1137/0214004","url":null,"abstract":"We present a formal framework for distributed databases, and we study the complexity of the concurrency control problem in this framework. Our transactions are partially ordered sets, of actions, as opposed to the straight-line programs of the centralized case. The concurrency control algorithm, or scheduler, is itself a distributed program. Three notions of performance of the scheduler are studied and interrelated: (i) its parallelism, (ii) the computational complexity of the problems it needs to solve, and (iii) the cost of communication between the various parts of the scheduler. We show that the number of messages necessary and sufficient to support a given level of parallelism is equal to the minmax value of a combinatorial game. We show that this game is PSPACE-complete. It follows that, unless NP=PSPACE, a scheduler cannot simultaneously minimize communication and be computationally efficient. This result, we argue, captures the quantum jump in complexity of the transition from centralized to distributed concurrency control problems.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115775659","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: 26
Census functions: An approach to VLSI upper bounds 普查函数:VLSI上界的一种方法
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1145/3828.3834
R. Lipton, J. Valdes
{"title":"Census functions: An approach to VLSI upper bounds","authors":"R. Lipton, J. Valdes","doi":"10.1145/3828.3834","DOIUrl":"https://doi.org/10.1145/3828.3834","url":null,"abstract":"A model of VLSI computation suitable for the description of algorithms at a high level is introduced. The model is basically a language to express parallel computations which can be efficiently implemented by a VLSI circuit. This language is used to describe area-time efficient algorithms for a few well known graph problems. The exact complexity of these algorithms and their relevance to recent work on the inherent limitations of VLSI computations are also presented.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116076099","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: 20
Unbounded program memory adds to the expressive power of first-order dynamic logic 无界程序内存增加了一阶动态逻辑的表现力
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.54
J. Tiuryn
{"title":"Unbounded program memory adds to the expressive power of first-order dynamic logic","authors":"J. Tiuryn","doi":"10.1109/SFCS.1981.54","DOIUrl":"https://doi.org/10.1109/SFCS.1981.54","url":null,"abstract":"The aim of this paper is to-compare various logics of programs with respect to their expressibility. The main result of the paper states that no logic of bounded memory programs is capable of defining the algebra of standard binary trees T = (T, CONS, NIL). Since the usual logics of unbounded memory programs are able to define the above algebra - we derive from the main result a couple of results which solve some questions about comparing expressive powers of programming logics.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121543065","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: 11
Possible futures, acceptances, refusals, and communicating processes 可能的未来、接受、拒绝和沟通过程
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.36
W. Rounds, S. Brookes
{"title":"Possible futures, acceptances, refusals, and communicating processes","authors":"W. Rounds, S. Brookes","doi":"10.1109/SFCS.1981.36","DOIUrl":"https://doi.org/10.1109/SFCS.1981.36","url":null,"abstract":"Two distinct models for the notion of communicating processes are introduced, developed and related. The first, called the possible-futures model, is a generalization to nondeterministic systems of the familiar derivative (Nerode equivalence class) construction. The second, called the acceptance-refusals model, is a slight strengthening of a model introduced by Hoare, Brookes, and Roscoe. The PF model can be mapped onto the AR model homomorphically, and the equivalence classes of this map can be characterized by imposing a very natural equivalence relation on the PF model. The resulting quotient algebra admits a complete partial order structure in which the algebraic operations are continuous.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130164822","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: 75
Symmetry in systems of asynchronous processes 异步过程系统中的对称性
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.42
J. Burns
{"title":"Symmetry in systems of asynchronous processes","authors":"J. Burns","doi":"10.1109/SFCS.1981.42","DOIUrl":"https://doi.org/10.1109/SFCS.1981.42","url":null,"abstract":"A new solution to the problem of deadlock-free mutual exclusion of N processes is given which uses less shared space than earlier solutions (one variable which may take on N values and N binary variables). The solution uses only indivisible reads and writes of shared variables for communication and is symmetric among the processes. Two definitions of symmetry are developed. The strong definition of symmetry requires that all processes be identically programmed and be started in identical states. However, this definition does not allow any solution to the problem of deadlock-free mutual exclusion using only reads and writes. The weaker definition admits the solution given. It is also shown that under weak symmetry N shared variables, at least one of which must be able to take on N values, are necessary.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114813206","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: 32
Optimizing synchronous systems 优化同步系统
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.34
C. Leiserson, J. Saxe
{"title":"Optimizing synchronous systems","authors":"C. Leiserson, J. Saxe","doi":"10.1109/SFCS.1981.34","DOIUrl":"https://doi.org/10.1109/SFCS.1981.34","url":null,"abstract":"The complexity of integrated-circuit chips produced today makes it feasible to build inexpensive, special-purpose subsystems that rapidly solve sophisticated problems on behalf of a general-purpose host computer. This paper contributes to the design methodology of efficient VLSI algorithms. We present a transformation that converts synchronous systems into more time-efficient, systolic implementations by removing combinational rippling. The problem of determining the optimized system can be reduced to the graph-theoretic single-destination-shortest-paths problem. More importantly from an engineering standpoint, however, the kinds of rippling that can be removed from a circuit at essentially no cost can be easily characterized. For example, if the only global communication in a system is broadcasting from the host computer, the broadcast can always be replaced by local communication.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114757170","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: 503
A circuit-size lower bound 电路大小的下界
22nd Annual Symposium on Foundations of Computer Science (sfcs 1981) Pub Date : 1981-10-28 DOI: 10.1109/SFCS.1981.1
R. Kannan
{"title":"A circuit-size lower bound","authors":"R. Kannan","doi":"10.1109/SFCS.1981.1","DOIUrl":"https://doi.org/10.1109/SFCS.1981.1","url":null,"abstract":"As remarked in Cook (1980), we do not know any nonlinear lower bound on the circuit size of a language in P or even in NP. The best known lower bound seems to be due to Paul (1975). Instead of trying to prove lower bounds on the circuit-size of a \"natural\" language, this note raises the question of whether some language in a class is of provably high circuit complexity. We show that for each nonnegative integer k, there is a language Lk in Σ2P ∩ π2P (of the Meyer and Stockmeyer (1972) hierarchy) Which does not have O(nk)-size circuits. The method is indirect and does not produce the language Lk. Other results of a similar nature are presented and several questions raised.","PeriodicalId":224735,"journal":{"name":"22nd Annual Symposium on Foundations of Computer Science (sfcs 1981)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1981-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131649751","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: 8
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