Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253466
J. Kok, P. Knijnenburg
The authors study the semantics of a language containing the usual operators of sequential composition, choice and parallel composition. It contains furthermore an atomizer which causes a statement to behave like an atomic action and thus increases the grain size of the parallelism. It follows that 'atomic' actions can be non-deterministic, deadlocking and even diverging. They set out to define a semantics that is an extension of the usual process algebra models. There are several possibilities for this extension (in particular for the choice operator) and they consider the so-called parallel choice. The paper includes the definition of an operational semantics, a denotational semantics and an outline of the proof of correctness. The paper is directed towards the modelling of the divergence. This is already non-trivial due to unbounded nondeterminism introduced by the atomizer: they have to extend the standard stream model. The proof of correctness requires a new technique in which they introduce orderings on proofs of transitions. They also provide an algebraic characterization of the finite part of the language.<>
{"title":"Divergence models for atomized statements and parallel choice","authors":"J. Kok, P. Knijnenburg","doi":"10.1109/ISTCS.1993.253466","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253466","url":null,"abstract":"The authors study the semantics of a language containing the usual operators of sequential composition, choice and parallel composition. It contains furthermore an atomizer which causes a statement to behave like an atomic action and thus increases the grain size of the parallelism. It follows that 'atomic' actions can be non-deterministic, deadlocking and even diverging. They set out to define a semantics that is an extension of the usual process algebra models. There are several possibilities for this extension (in particular for the choice operator) and they consider the so-called parallel choice. The paper includes the definition of an operational semantics, a denotational semantics and an outline of the proof of correctness. The paper is directed towards the modelling of the divergence. This is already non-trivial due to unbounded nondeterminism introduced by the atomizer: they have to extend the standard stream model. The proof of correctness requires a new technique in which they introduce orderings on proofs of transitions. They also provide an algebraic characterization of the finite part of the language.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116719277","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253479
H. Siegelmann, Eduardo Sontag
The authors pursue a particular approach to analog computation, based on dynamical systems of the type used in neural networks research. The systems have a fixed structure, invariant in time, corresponding to an unchanging number of 'neurons'. If allowed exponential time for computation, they turn out to have unbounded power. However, under polynomial-time constraints there are limits on their capabilities, though being more powerful than Turing machines. These networks are not likely to solve polynomially-NP-hard problems, as the equality 'P=NP' implies the almost complete collapse of the standard polynomial hierarchy. In contrast to classical computational models, the models studied exhibit at least some robustness with respect to noise and implementation errors.<>
{"title":"Analog computation via neural networks","authors":"H. Siegelmann, Eduardo Sontag","doi":"10.1109/ISTCS.1993.253479","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253479","url":null,"abstract":"The authors pursue a particular approach to analog computation, based on dynamical systems of the type used in neural networks research. The systems have a fixed structure, invariant in time, corresponding to an unchanging number of 'neurons'. If allowed exponential time for computation, they turn out to have unbounded power. However, under polynomial-time constraints there are limits on their capabilities, though being more powerful than Turing machines. These networks are not likely to solve polynomially-NP-hard problems, as the equality 'P=NP' implies the almost complete collapse of the standard polynomial hierarchy. In contrast to classical computational models, the models studied exhibit at least some robustness with respect to noise and implementation errors.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114790508","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253458
Ran El-Yaniv, R. Karp
Mortgage refinancing is a complex real-life problem involving a sequence of decisions, each of which requires a trade-off between the transaction cost associated with refinancing and the benefit of obtaining a lower interest rate. The authors present a simplified mathematical model of this problem. Within this model, they seek to determine the best possible competitive ratio achievable by an on-line mortgage refinancing policy. The main results are the following: under the assumption that the initial mortgage is obtained with an interest rate M and that future interest rates cannot decrease below m>or=0, they show a lower bound r= Omega (/sup 1nM///sub (m+1)lnlnM/) on the competitive ratio of any mortgage refinancing policy. Then they give an on-line policy that is optimal in some special cases, including the cases m=0 and M<(1+/sup 2///sub m+1/)(m+2). For other values of m, M the on-line policy is proven to be r/sup 2/-competitive.<>
{"title":"The mortgage problem","authors":"Ran El-Yaniv, R. Karp","doi":"10.1109/ISTCS.1993.253458","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253458","url":null,"abstract":"Mortgage refinancing is a complex real-life problem involving a sequence of decisions, each of which requires a trade-off between the transaction cost associated with refinancing and the benefit of obtaining a lower interest rate. The authors present a simplified mathematical model of this problem. Within this model, they seek to determine the best possible competitive ratio achievable by an on-line mortgage refinancing policy. The main results are the following: under the assumption that the initial mortgage is obtained with an interest rate M and that future interest rates cannot decrease below m>or=0, they show a lower bound r= Omega (/sup 1nM///sub (m+1)lnlnM/) on the competitive ratio of any mortgage refinancing policy. Then they give an on-line policy that is optimal in some special cases, including the cases m=0 and M<(1+/sup 2///sub m+1/)(m+2). For other values of m, M the on-line policy is proven to be r/sup 2/-competitive.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"13 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132291534","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253483
R. Cole, R. Hariharan, M. Paterson, Uri Zwick
The paper considers the exact number of character comparisons needed to find all occurrences of a pattern of length m in a text of length n using on-line and general algorithms. For on-line algorithms, a lower bound of about (1+/sup 9///sub 4(m+1)/).n character comparisons is obtained. For general algorithms, a lower bound of about (1+/sup 2///sub m+3/).n character comparisons is obtained. These lower bound complement an on-line upper bound of about (1+/sup 8///sub 3(m+1)/).n comparisons obtained recently by Cole and Hariharan (1992). The lower bounds are obtained by finding patterns with interesting combinatorial properties (these are the hard to find patterns). It is also shown that for some patterns off-line algorithms can be more efficient than on-line algorithms.<>
{"title":"Which patterns are hard to find? (String matching)","authors":"R. Cole, R. Hariharan, M. Paterson, Uri Zwick","doi":"10.1109/ISTCS.1993.253483","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253483","url":null,"abstract":"The paper considers the exact number of character comparisons needed to find all occurrences of a pattern of length m in a text of length n using on-line and general algorithms. For on-line algorithms, a lower bound of about (1+/sup 9///sub 4(m+1)/).n character comparisons is obtained. For general algorithms, a lower bound of about (1+/sup 2///sub m+3/).n character comparisons is obtained. These lower bound complement an on-line upper bound of about (1+/sup 8///sub 3(m+1)/).n comparisons obtained recently by Cole and Hariharan (1992). The lower bounds are obtained by finding patterns with interesting combinatorial properties (these are the hard to find patterns). It is also shown that for some patterns off-line algorithms can be more efficient than on-line algorithms.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123717926","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253465
Z. Khasidashvili
The author introduces persistent term rewriting systems (PTRSs) by restricting redex-creation during reductions in orthogonal term rewriting systems (OTRSs). In particular, recursive (applicative) program schemes (RPSs) considered as TRSs, are persistent. Two PTRSs R and R' are syntactically equivalent when any term t has an R-normal form if it has an R'-normal form and they coincide. He proves that syntactic equivalence is decidable for PTRSs. Further, he shows that the equivalence problem (over all continuous interpretations) is decidable for RPSs with unary basic functions by reducing the question to a decidable number-theory problem. Finally, he shows that weak and strong normalization and the reducibility problem also are decidable in PTRSs.<>
{"title":"On the equivalence of persistent term rewriting systems and recursive program schemes","authors":"Z. Khasidashvili","doi":"10.1109/ISTCS.1993.253465","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253465","url":null,"abstract":"The author introduces persistent term rewriting systems (PTRSs) by restricting redex-creation during reductions in orthogonal term rewriting systems (OTRSs). In particular, recursive (applicative) program schemes (RPSs) considered as TRSs, are persistent. Two PTRSs R and R' are syntactically equivalent when any term t has an R-normal form if it has an R'-normal form and they coincide. He proves that syntactic equivalence is decidable for PTRSs. Further, he shows that the equivalence problem (over all continuous interpretations) is decidable for RPSs with unary basic functions by reducing the question to a decidable number-theory problem. Finally, he shows that weak and strong normalization and the reducibility problem also are decidable in PTRSs.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125769950","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253470
R. I. Greenberg, Jau-Der Shih
The paper provides an efficient method to find all feasible offsets for a given separation in a VLSI channel routing problem in one layer. The prior literature considers this task only for problems with no single-sided nets. When single-sided nets are included, the worst-case solution time increases from Theta (n) to Omega (n/sup 2/), where n is the number of nets. But, if the number of columns c is O(n), one can solve the problem in time O(n/sup 1.5/lg n), which improves upon a 'naive' O(cn) approach. As a corollary of this result, the same time bound suffices to find the optimal offset (the one that minimizes separation). Better running times are obtained when there are no two-sided nets or all single-sided nets are on one side to the channel. The authors also give improvements upon the naive approach for c not=O(n), including an algorithm with running time independent of c.<>
{"title":"Feasible offset and optimal offset for single-layer channel routing","authors":"R. I. Greenberg, Jau-Der Shih","doi":"10.1109/ISTCS.1993.253470","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253470","url":null,"abstract":"The paper provides an efficient method to find all feasible offsets for a given separation in a VLSI channel routing problem in one layer. The prior literature considers this task only for problems with no single-sided nets. When single-sided nets are included, the worst-case solution time increases from Theta (n) to Omega (n/sup 2/), where n is the number of nets. But, if the number of columns c is O(n), one can solve the problem in time O(n/sup 1.5/lg n), which improves upon a 'naive' O(cn) approach. As a corollary of this result, the same time bound suffices to find the optimal offset (the one that minimizes separation). Better running times are obtained when there are no two-sided nets or all single-sided nets are on one side to the channel. The authors also give improvements upon the naive approach for c not=O(n), including an algorithm with running time independent of c.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130288229","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253476
A. Condon, Diane Hernek
The authors initiate a study of random walks on undirected graphs with colored edges. An adversary specifies a sequence of colors before the walk begins, and it dictates the color of edge to be followed at each step. They analyze the extent to which the adversary can influence the behavior of such a random walk, in terms of the expected cover time. They prove tight upper and lower bounds on the expected cover time of colored undirected graphs. They show that, in general, graphs with two colors have exponential expected cover time, and graphs with three or more colors have doubly-exponential expected cover time. They also give polynomial bounds on the expected cover time in a number of interesting special cases. They describe applications of these results to understanding the dominant eigenvectors of products and weighted averages of stochastic matrices, and to problems on time-inhomogeneous Markov chains.<>
{"title":"Random walks on colored graphs","authors":"A. Condon, Diane Hernek","doi":"10.1109/ISTCS.1993.253476","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253476","url":null,"abstract":"The authors initiate a study of random walks on undirected graphs with colored edges. An adversary specifies a sequence of colors before the walk begins, and it dictates the color of edge to be followed at each step. They analyze the extent to which the adversary can influence the behavior of such a random walk, in terms of the expected cover time. They prove tight upper and lower bounds on the expected cover time of colored undirected graphs. They show that, in general, graphs with two colors have exponential expected cover time, and graphs with three or more colors have doubly-exponential expected cover time. They also give polynomial bounds on the expected cover time in a number of interesting special cases. They describe applications of these results to understanding the dominant eigenvectors of products and weighted averages of stochastic matrices, and to problems on time-inhomogeneous Markov chains.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128839188","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253475
N. Linial, D. Peleg, Y. Rabinovich, M. Saks
The paper concerns some extremal problems on packing spheres in graphs and covering graphs by spheres. Tight bounds are provided for these problems on general graphs. The bounds are then applied to answer the following question: Let f be a nonnegative function defined on the vertices of a graph G, and suppose one has a lower bound on the local averages of f, i.e., on f's average over every j-neighborhood in G for j=1,. . .,r. What can be concluded globally? I.e, what can be said about the average of f over all G? This question arose in connection with issues of locality in distributed network computation. The average estimation problem with unit radius balls is also studied for some special classes of graphs.<>
{"title":"Sphere packing and local majorities in graphs","authors":"N. Linial, D. Peleg, Y. Rabinovich, M. Saks","doi":"10.1109/ISTCS.1993.253475","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253475","url":null,"abstract":"The paper concerns some extremal problems on packing spheres in graphs and covering graphs by spheres. Tight bounds are provided for these problems on general graphs. The bounds are then applied to answer the following question: Let f be a nonnegative function defined on the vertices of a graph G, and suppose one has a lower bound on the local averages of f, i.e., on f's average over every j-neighborhood in G for j=1,. . .,r. What can be concluded globally? I.e, what can be said about the average of f over all G? This question arose in connection with issues of locality in distributed network computation. The average estimation problem with unit radius balls is also studied for some special classes of graphs.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128449940","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253480
Yefim Dinitz
Two vertices v and u of an undirected graph are called k-edge-connected if there exist k edge-disjoint paths between v and u. The equivalence classes of this relation are called the k-edge-connected components. The author suggests graph structures and an incremental algorithm to maintain k-edge-connected components for the case k=4. Any sequence of a q queries Same-k-Component? and updates Insert-Edge on an n-vertex graph can be performed in O(q sigma (q,n)+n log n) time, with O(m+n log n) preprocessing (m is the number of edges in the initial graph). Besides, an algorithm for maintaining k-edge-connected components (k arbitrary) in a (k-1)-edge-connected graph is presented. The complexity is O((q+n) alpha (q,n)), with O(m+k/sup 2/n log(n/k)) preprocessing.<>
{"title":"Maintaining the 4-edge-connected components of a graph on-line","authors":"Yefim Dinitz","doi":"10.1109/ISTCS.1993.253480","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253480","url":null,"abstract":"Two vertices v and u of an undirected graph are called k-edge-connected if there exist k edge-disjoint paths between v and u. The equivalence classes of this relation are called the k-edge-connected components. The author suggests graph structures and an incremental algorithm to maintain k-edge-connected components for the case k=4. Any sequence of a q queries Same-k-Component? and updates Insert-Edge on an n-vertex graph can be performed in O(q sigma (q,n)+n log n) time, with O(m+n log n) preprocessing (m is the number of edges in the initial graph). Besides, an algorithm for maintaining k-edge-connected components (k arbitrary) in a (k-1)-edge-connected graph is presented. The complexity is O((q+n) alpha (q,n)), with O(m+k/sup 2/n log(n/k)) preprocessing.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115083129","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}
Pub Date : 1993-06-07DOI: 10.1109/ISTCS.1993.253468
A. Itai, H. Shachnai
The authors study algorithms for adaptive source routing in high speed networks, where some of the links are unreliable. Thus, the delivery of a single message towards its destination may require trying several paths. Assuming an a priori knowledge of the failure probabilities of links, the objective is to devise routing strategies which minimize the expected delivery cost of a single message. They describe optimal strategies for two cases: a tree-like network and a general serial/parallel graph. Whereas, in the first case, the greedy algorithm is shown to be optimal (i.e., it is best to try the paths by decreasing order of their success probabilities), there is no simple decision rule for the second case. However, using some properties of serial/parallel graphs they show, that an optimal strategy can be easily derived from a fixed sequence of paths. They give an algorithm, polynomial in the number of links, for finding this sequence. For a general network they show, that the problem of devising an optimal strategy can be solved in polynomial space and is Hash P-Hard, and that the minimal expected delivery cost in a given network is also hard to approximate. Finally, they show, that for scenarios of adaptive source routing, the common greedy is not even a constant approximation to the optimal strategy.<>
{"title":"Adaptive source routing in high-speed networks","authors":"A. Itai, H. Shachnai","doi":"10.1109/ISTCS.1993.253468","DOIUrl":"https://doi.org/10.1109/ISTCS.1993.253468","url":null,"abstract":"The authors study algorithms for adaptive source routing in high speed networks, where some of the links are unreliable. Thus, the delivery of a single message towards its destination may require trying several paths. Assuming an a priori knowledge of the failure probabilities of links, the objective is to devise routing strategies which minimize the expected delivery cost of a single message. They describe optimal strategies for two cases: a tree-like network and a general serial/parallel graph. Whereas, in the first case, the greedy algorithm is shown to be optimal (i.e., it is best to try the paths by decreasing order of their success probabilities), there is no simple decision rule for the second case. However, using some properties of serial/parallel graphs they show, that an optimal strategy can be easily derived from a fixed sequence of paths. They give an algorithm, polynomial in the number of links, for finding this sequence. For a general network they show, that the problem of devising an optimal strategy can be solved in polynomial space and is Hash P-Hard, and that the minimal expected delivery cost in a given network is also hard to approximate. Finally, they show, that for scenarios of adaptive source routing, the common greedy is not even a constant approximation to the optimal strategy.<<ETX>>","PeriodicalId":281109,"journal":{"name":"[1993] The 2nd Israel Symposium on Theory and Computing Systems","volume":"118 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114035509","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}
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