On finitely ambiguous B\"uchi automata

Unambiguous B\"uchi automata, i.e. B\"uchi automata allowing only one accepting run per word, are a useful restriction of B\"uchi automata that is well-suited for probabilistic model-checking. In this paper we propose a more permissive variant, namely finitely ambiguous B\"uchi automata, a generalisation where each word has at most $k$ accepting runs, for some fixed $k$. We adapt existing notions and results concerning finite and bounded ambiguity of finite automata to the setting of $\omega$-languages and present a translation from arbitrary nondeterministic B\"uchi automata with $n$ states to finitely ambiguous automata with at most $3^n$ states and at most $n$ accepting runs per word

On the lattice of subgroups of a free group: complements and rank

A $\vee$-complement of a subgroup $H \leqslant \mathbb{F}_n$ is a subgroup $K \leqslant \mathbb{F}_n$ such that $H \vee K = \mathbb{F}_n$. If we also ask $K$ to have trivial intersection with $H$, then we say that $K$ is a $\oplus$-complement of $H$. The minimum possible rank of a $\vee$-complement (resp. $\oplus$-complement) of $H$ is called the $\vee$-corank (resp. $\oplus$-corank) of $H$. We use Stallings automata to study these notions and the relations between them. In particular, we characterize when complements exist, compute the $\vee$-corank, and provide language-theoretical descriptions of the sets of cyclic complements. Finally, we prove that the two notions of corank coincide on subgroups that admit cyclic complements of both kinds.Comment: 27 pages, 5 figure

Bayesian design of synthetic biological systems

Here we introduce a new design framework for synthetic biology that exploits the advantages of Bayesian model selection. We will argue that the difference between inference and design is that in the former we try to reconstruct the system that has given rise to the data that we observe, while in the latter, we seek to construct the system that produces the data that we would like to observe, i.e. the desired behavior. Our approach allows us to exploit methods from Bayesian statistics, including efficient exploration of models spaces and high-dimensional parameter spaces, and the ability to rank models with respect to their ability to generate certain types of data. Bayesian model selection furthermore automatically strikes a balance between complexity and (predictive or explanatory) performance of mathematical models. In order to deal with the complexities of molecular systems we employ an approximate Bayesian computation scheme which only requires us to simulate from different competing models in order to arrive at rational criteria for choosing between them. We illustrate the advantages resulting from combining the design and modeling (or in-silico prototyping) stages currently seen as separate in synthetic biology by reference to deterministic and stochastic model systems exhibiting adaptive and switch-like behavior, as well as bacterial two-component signaling systems.Comment: 36 pages, 16 figure

International Research Project on Job Retention and Return to Work Strategies for Disabled Workers: Germany

[Excerpt] The International Research Project on Job Retention and Return to Work Strategies for Disabled Workers is an initiative of the International Labour Organisation (ILO) and the Global Applied Research and Information Network on Employment and Training (GLADNET). It reflects ILO and GLADNET joint aims of establishing a base for cross-national research and strengthening links between research analysis and policy reform in the field of employment of disabled people. The Project is a response to a combination of developments which highlight the need for more effective policies and practices in support of workers whose prospects of remaining in employment are jeopardised by work injury, illness or disability. Persons with disabilities are increasingly claiming rights to stay in work as well as to access employment. Pressures on state budgets, the rising costs of compensation claims and disability benefits, and changes in the structure of the labour market are strengthening policies in favour of job retention and return to work. Enterprises are developing their own strategies to minimise the costs of disability and to retain valued employees. Overall, the balance of responsibility is shifting from the state to the enterprise. Policies and practices to prevent disabled workers from leaving work unnecessarily, and to facilitate rapid return to employment if job loss cannot be prevented, are recent developments in many countries. The cross-national exchange of information on initiatives and their effects is limited. The first aim of this Project has been to gather information about what has been attempted, by whom, for what purposes, in which contexts and to what effects. The second, more ambitious, aim, is to examine the interaction between the various policies and practices, identify dysfunctions, and work towards more coherent and cost-effective strategies for job retention and return to work which might be applied in different national systems. The ultimate objective is to identify strategies which can be put into effect in the workplace

Use of Earth Resources Technological Satellite (ERTS) data in a natural resource inventory

There are no author-identified significant results in this report

Theoretical issues in the interpretation of Cappadocian, a not-so-dead Greek contact language

Cappadocian is a mixed Greek-Turkish dialect continuum spoken in the Turkish Central Anatolia Region until the population exchange between Greece and Turkey in the 1920s. Only a few Cappadocian dialects are still spoken in present-day Greece. Since the publication of Thomason and Kaufman’s Language Contact, Creolization, and Genetic Linguistics in 1988, Cappadocian has attracted the attention of historical and contact linguists, because of its unique mixed character. In this paper, I will discuss a number of theoretical issues in the interpretation of the linguistic structure of Cappadocian, focusing on the following topics: (1) the status of loan phonemes and loan morphemes in contact languages, (2) the distinction between code switching and code mixing in relation to Poplack’s Free Morpheme Constraint, (3) the schizoid typology of contact languages

Decline and decadence in Iraq and Syria after the age of Avicenna? : ʿAbd al-Laṭīf al-Baghdādī (1162–1231) between myth and history

‘Abd al-Laṭīf al-Baghdādī’s (d. 1231) work Book of the Two Pieces of Advice (Kitāb al Nasīḥatayn) challenges the idea that Islamic medicine declined after the twelfth century AD. Moreover, it offers some interesting insights into the social history of medicine. ‘Abd al-Laṭīf advocated using the framework of Greek medical epistemology to criticize the rationalist physicians of his day; he argued that female and itinerant practitioners, relying on experience, were superior to some rationalists. He lambasted contemporaneous medical education because it put too much faith in a restricted number of textbooks such as the Canon by Ibn Sīnā (Avicenna, d. 1037) or imperfect abridgments