424 research outputs found
Descriptional Complexity of Three-Nonterminal Scattered Context Grammars: An Improvement
Recently, it has been shown that every recursively enumerable language can be
generated by a scattered context grammar with no more than three nonterminals.
However, in that construction, the maximal number of nonterminals
simultaneously rewritten during a derivation step depends on many factors, such
as the cardinality of the alphabet of the generated language and the structure
of the generated language itself. This paper improves the result by showing
that the maximal number of nonterminals simultaneously rewritten during any
derivation step can be limited by a small constant regardless of other factors
A review paper on Integrated Aquaculture Benefits Project at Federal College of Forestry, Ibadan
This paper highlights some of the practices involved in integrated aquaculture such as poultry-cum-fish, pig-cum-fish, sheep and goat-cum-fish and grasscutter-cum-fish. Also the role of fisheries in alleviating protein deficiency was reviewed. Successful research findings on these practices in aquaculture at the Federal College of Forestry, Jericho, Ibadan (Nigeria) will eventually lead to alleviating protein deficiency of the inhabitants of the largest city in West African thus alleviating poverty in the natio
Rule-restricted Automaton-grammar transducers: Power and Linguistic Applications
This paper introduces the notion of a new transducer as a two-component system, which consists of a nite automaton and a context-free grammar. In essence, while the automaton reads its input string, the grammar produces its output string, and their cooperation is controlled by a set, which restricts the usage of their rules. From a theoretical viewpoint, the present paper discusses the power of this system working in an ordinary way as well as in a leftmost way. In addition, the paper introduces an appearance checking, which allows us to check whether some symbols are present in the rewritten string, and studies its e ect on the power. It achieves the following three main results. First, the system generates and accepts languages de ned by matrix grammars and partially blind multi-counter automata, respectively. Second, if we place a leftmost restriction on derivation in the context-free grammar, both accepting and generating power of the system is equal to generative power of context-free grammars. Third, the system with appearance checking can accept and generate all recursively enumerable languages. From more pragmatical viewpoint, this paper describes several linguistic applications. A special attention is paid to the Japanese-Czech translation
Modernizing of Dynamometer for Passenger Vehicle
CĂlem tĂ©to práce je navrhnout optimalizaci danĂ© válcovĂ© zkušebny. Aby bylo moĹľnĂ© provĂ©st optimalizaci stávajĂcĂ zkušebny, je nutnĂ© zjistit, jakĂ© nedostatky válcová zkušebna má. Po zjištÄ›nĂ nedostatkĹŻ je tĹ™eba provĂ©st návrhy Ăşprav válcovĂ© zkušebny. V práci je zjištÄ›no, Ĺľe válcová zkušebna nemá dostateÄŤnĂ˝ brzdnĂ˝ vĂ˝kon. Na základÄ› tohoto zjištÄ›nĂ jsou vybrány dvÄ› varianty Ăşprav. PrvnĂ je vĂ˝mÄ›na dynamometru a druhá je vloĹľenĂ pĹ™evodovky do válcovĂ© zkušebny. Na pĹ™evodovĂ© skĹ™Ăni je provedena pevnostnĂ analĂ˝za.The basic aim of this thesis is to design optimisation of the brake bench in question. For this kind of optimisation, it was necessary to ascertain which failings the current brake bench exhibited. After ascertaining such failings, design of modification to this brake bench must be performed. In terms of this thesis, it was ascertained that the brake bench has insufficient brake power. Based on this finding, two alternatives for modifications have been selected. The first is replacement of the dynamometer and the second is insertion of a gear box into the brake bench. Rigidity analysis was performed on the gear casing.
Two-way metalinear PC grammar systems and their descriptional complexity
Besides a derivation step and a communication step, a two-way PC grammar system can make a reduction step during which it reduces the right-hand side of a context-free production to its left-hand side. This paper proves that every non-unary recursively enumerable language is defined by a centralized two-way grammar system, ┌, with two metalinear components in a very economical way. Indeed, ┌'s master has only three nonterminals and one communication production; furthermore, it produces all sentential forms with no more than two occurrences of nonterminals. In addition, during every computation, ┌ makes a single communication step. Some variants of two-way PC grammar systems are discussed in the conclusion of this paper
Descriptional complexity of multi-continuous grammars
The present paper discusses multi-continuous grammars and their descriptional complexity with respect to the number of nonterminals. It proves that six-nonterminal multi-continuous grammars characterize the family of recursively enumerable languages. In addition, this paper formulates an open problem area closely related to this characterization
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