On inferring zero-reversible languages

We use a language-theoretic result for zero-reversible languages to show that there exists a linear time inference method for this class of languages using positive data only

On lexicographic enumeration of regular and context-free languages

We show that it is possible to efficiently enumerate the words of a regular language in lexicographic order. The time needed for generating the next word is O(n) when enumerating words of length n. We also define a class of context-free languages for which efficient enumeration is possible

Katsaus lääketieteelliseen 3D-tulostamiseen

3D-tulostaminen on mahdollistanut mitä erilaisimpien tuotteiden tehokkaan ja tarkan valmistamisen aina autoista ja taloista vaatteisiin ja ruokaan. Eräs sen jännittävimmistä sovellusalueista on kuitenkin uusiutuvan lääketieteen ala. Siinä sovellettavalla 3D-tulostamisen teknologialla on potentiaali 1) tulostaa korvaavia osia potilaan vahingoittuneille kudoksille sekä 2) valmistaa malleja ihmiskehoon pohjautuvista kudoksista. Lääketieteelliseen 3D-tulostamiseen on kehitelty lukuisia erilaisia tekniikoita, joista suosituimpia elävien kudosten valmistamista varten ovat mustesuihkubiotulostus, painepohjainen biotulostus sekä laserpohjainen biotulostus. Tämän katsauksen tarkoituksena on esitellä alan keskeisiä käsitteitä, perehtyä tarkemmin käytettyihin tekniikoihin sekä käsitellä lääketieteellisessä 3D-tulostamisessa käytettyjä materiaaleja.3D printing has made it possible to effectively and precisely produce the most diverse kinds of productions from cars and houses to clothes and food. One of its most exciting applications is in the field regenerative medicine where 3D printing has potential to produce 1) replicates to patient’s damaged tissues, and 2) models of tissues based on human body. 3D printing in medicine includes several techniques. The most popular techniques for producing living tissues are drop-by-drop printing, extrusion printing and laser assisted based (LAB) printing. The purpose of this survey is to present the key terminology of the field, and to consider the techniques and materials used

A Note on the Emptiness of Intersection Problem for Left Szilárd Languages

As left Szilárd languages form a subclass of simple deterministic languages and even a subclass of super-deterministic languages, we know that their equivalence problem is decidable. In this note we show that their emptiness of intersection problem is undecidable. The proof follows the lines of the corresponding proof for simple deterministic languages, but some technical tricks are needed. This result sharpens the borderline between decidable and undecidable problems in formal language theory

Inferring pure context-free languages from positive data

We study the possibilities to infer pure context-free languages from positive data. We can show that while the whole class of pure context-free languages is not inferable from positive data, it has interesting subclasses which have the desired inference property. We study uniform pure languages, i.e., languages generated by pure grammars obeying restrictions on the length of the right hand sides of their productions, and pure languages generated by deterministic pure grammars

Implemeting a component-based tool for interactive synthesis of UML statechart diagrams

The Unified Modeling Language (UML) has an indisputable role in objectoriented software development. It provides several diagram types viewing a system from different perspectives. Currently available systems have relatively modest tool support for comparing, merging, synthesizing, and slicing UML diagrams based on their semantical relationships. Minimally Adequate Synthesizer (MAS) is a tool that synthesizes UML statechart diagrams from sequence diagrams in an interactive manner. It follows Angluin's framework of minimally adequate teacher to infer the desired statechart diagram with the help of membership and equivalence queries. MAS can also synthesize sequence diagrams into an edited or manually constructed statechart diagram. In this paper we discuss problems related to a practical implementation of MAS and its integration with two existing tools (Nokia TED and Rational Rose) supporting UML-based modeling. We also discuss information exchange techniques that could be used to allow the usage of other CASE tools supporting UML