Ehrenfeucht-Fraisse Games on Omega-Terms

Fragments of first-order logic over words can often be characterized in terms of finite monoids or finite semigroups. Usually these algebraic descriptions yield decidability of the question whether a given regular language is definable in a particular fragment. An effective algebraic characterization can be obtained from identities of so-called omega-terms. In order to show that a given fragment satisfies some identity of omega-terms, one can use Ehrenfeucht-Fraisse games on word instances of the omega-terms. The resulting proofs often require a significant amount of book-keeping with respect to the constants involved. In this paper we introduce Ehrenfeucht-Fraisse games on omega-terms. To this end we assign a labeled linear order to every omega-term. Our main theorem shows that a given fragment satisfies some identity of omega-terms if and only if Duplicator has a winning strategy for the game on the resulting linear orders. This allows to avoid the book-keeping. As an application of our main result, we show that one can decide in exponential time whether all aperiodic monoids satisfy some given identity of omega-terms, thereby improving a result of McCammond (Int. J. Algebra Comput., 2001)

Quo vadis? How to measure the quality of local and regional development processes?

Today most activities which seem to be sound, cosy and helpful - or sometimes simply useful - are called ?sustainable'. Of course the requirements for measuring sustainability increased rapidly. Many different systems of indicators and conflicting opinions about the adequate approach characterise the present situation. Nevertheless we add another system with an specific approach to evaluate processes of local and regional development. In our opinion it is able notably to refer to the quality of the concept of sustainability. The basic system is threefold and bears analogy to the model of total quality management. We distinguish between: · The assessment of projects with respect to material, procedural and ethical implications. The conceptual framework is translated into an evaluation checklist to systematise the discussion of the character and general impact of a given project or programme. The methodology of this section has been presented at the 39th ERSA Congress 1999 in Dublin even and until now has been applied in different fields. · The assessment of development processes in terms of organisation, methodology, contents and legal demands. This section will be the main part of our presentation. · And the assessment of the state of the region which actually is a 'work in progress'. It will combine elements of 'top-down indicators, deduced from the international and national discussion of the CSD-scheme, with elements of regional specific indicators based on a bottom-up approach which defines regional specific goals of development according to a transdisciplinary approach of how to experience the local and regional space. Our methodology is based on self-evaluation and it can come into operation at an early stage accompanying the activities over the whole life cycle. The assessment of development processes is to be done from the local and regional actors for themselves, accompanied by scientific experts. It depends on four principles: · The people concerned are the experts. They get involved in learning processes. · The focus of the assessment is on credibility and transparency. · Development processes need a minimum of quality. The standard is fixed. · The quality management can be used in a flexible way to allow the assessment of different processes according to the communities main focus. The whole project of quality management is closely coupled with the regional Agenda 21 in the Lake of Constance- region as it has been shown eat the 40th ERSA Congress 2000 in Barcelona. Together with the network of 13 regional contact points in Switzerland, Austria, Germany and the Principality of Liechtenstein the different sections has been discussed and field-tested. 437 words Key words: sustainability, Agenda 21, quality management, development processes, transdisciplinarity

Financing Constraints and the Timing of Innovations in the German Services Sector

Using newly available data at the firm level, this study provides convincing evidence of the importance of financial constraints in explaining the timing of innovations in the German services sector. Based on a dynamic model of firms' optimal R&D behavior under financial constraints, we estimate various versions of an econometric specification of the model with dichotomous innovation data by using a univariate ordered probit model and a newly developed modification of it. The modified econometric estimation strategies takes into account that some of the regressors are measured on an ordinal scale. Our results are consistent with the theoretical view that, because of capital markets imperfections, internal finance should be an important determinant of innovative activities by private firms in the manufacturing sector as well as in the services sector.

Rsp5 promotes Gene Activation mediated by 9aaTAD Transcription Factors Oaf1 and Gal4

Nine-amino-acid transactivation domain, 9aaTAD, defines a large superfamily of yeast and mammals transcription factors. The transactivation of the 9aaTAD has been addressed to multiple general co-activators TAF9, MED15, CBP and p300. We demonstrate for the 9aaTAD transcription factors Oaf1 and Gal4 functional and physical interaction with E3-Ubiquitin Ligase Rsp5. The Rsp5-associations with RNA polymerase II and TFIID were reported previously

Neural Network Modelling of Constrained Spatial Interaction Flows

Fundamental to regional science is the subject of spatial interaction. GeoComputation - a new research paradigm that represents the convergence of the disciplines of computer science, geographic information science, mathematics and statistics - has brought many scholars back to spatial interaction modeling. Neural spatial interaction modeling represents a clear break with traditional methods used for explicating spatial interaction. Neural spatial interaction models are termed neural in the sense that they are based on neurocomputing. They are clearly related to conventional unconstrained spatial interaction models of the gravity type, and under commonly met conditions they can be understood as a special class of general feedforward neural network models with a single hidden layer and sigmoidal transfer functions (Fischer 1998). These models have been used to model journey-to-work flows and telecommunications traffic (Fischer and Gopal 1994, Openshaw 1993). They appear to provide superior levels of performance when compared with unconstrained conventional models. In many practical situations, however, we have - in addition to the spatial interaction data itself - some information about various accounting constraints on the predicted flows. In principle, there are two ways to incorporate accounting constraints in neural spatial interaction modeling. The required constraint properties can be built into the post-processing stage, or they can be built directly into the model structure. While the first way is relatively straightforward, it suffers from the disadvantage of being inefficient. It will also result in a model which does not inherently respect the constraints. Thus we follow the second way. In this paper we present a novel class of neural spatial interaction models that incorporate origin-specific constraints into the model structure using product units rather than summation units at the hidden layer and softmax output units at the output layer. Product unit neural networks are powerful because of their ability to handle higher order combinations of inputs. But parameter estimation by standard techniques such as the gradient descent technique may be difficult. The performance of this novel class of spatial interaction models will be demonstrated by using the Austrian interregional traffic data and the conventional singly constrained spatial interaction model of the gravity type as benchmark. References Fischer M M (1998) Computational neural networks: A new paradigm for spatial analysis Environment and Planning A 30 (10): 1873-1891 Fischer M M, Gopal S (1994) Artificial neural networks: A new approach to modelling interregional telecommunciation flows, Journal of Regional Science 34(4): 503-527 Openshaw S (1993) Modelling spatial interaction using a neural net. In Fischer MM, Nijkamp P (eds) Geographical information systems, spatial modelling, and policy evaluation, pp. 147-164. Springer, Berlin

A methodology for neural spatial interaction modelling

This paper presents a methodology for neural spatial interaction modelling. Particular emphasis is laid on design, estimation and performance issues in both cases, unconstrained and singly constrained spatial interaction. Families of classical neural network models, but also less classical ones such as product unit neural network models are considered. Some novel classes of product unit and summation unit models are presented for the case of origin or destination constrained spatial interaction flows. The models are based on a modular connectionist architecture that may be viewed as a linked collection of functionally independent neural modules with identical feedforward topologies, operating under supervised learning algorithms. Parameter estimation is viewed as Maximum Likelihood (ML) learning. The nonconvex nature of the loss function makes the Alopex procedure, a global search procedure, an attractive and appropriate optimising scheme for ML learning. A benchmark comparison against the classical gravity models illustrates the superiority of both, the unconstrained and the origin constrained, neural network model versions in terms of generalization performance measured by Kullback and Leibler`s information criterion. Hereby, the authors make use of the bootstrapping pairs approach to overcome the largely neglected problem of sensitivity to the specific splitting of the data into training, internal validation and testing data sets, and to get a better statistical picture of prediction variability of the models. Keywords: Neural spatial interaction models, origin constrained or destination constrained spatial interaction, product unit network, Alopex procedure, boostrapping, benchmark performance tests.

Lepton Mixing Patterns from a Scan of Finite Discrete Groups

The recent discovery of a non-zero value of the mixing angle theta_13 has ruled out tri-bimaximal mixing as the correct lepton mixing pattern generated by some discrete flavor symmetry (barring large next-to-leading order corrections in concrete models). In this work we assume that neutrinos are Majorana particles and perform a general scan of all finite discrete groups with order less than 1536 to obtain their predictions for lepton mixing angles. To our surprise, the scan of over one million groups only yields 3 interesting groups that give lepton mixing patterns which lie within 3-sigma of the current best global fit values. A systematic way to categorize such groups and the implications for flavor symmetry are discussed.Comment: 15 pages, 3 figures, references added and minor improvements, matches version to be appeared in Physics Letters

Percolation effects during ionic motion

Interest in materials exhibiting oxygen ion and/or proton conduction has increased during the last years owing to their great importance for energy and environmental applications. Ceria-based oxides are regarded as key oxide materials because rare earth-doped ceria shows a high oxygen ion conductivity even at intermediate temperatures. Using density-functional theory (DFT), we have investigated defect interaction and oxygen migration energies as well. By means of Kinetic Monte Carlo (KMC) simulations we then investigated the oxygen ion conductivity. We show that all interactions between the defects, namely vacancy-dopant attraction, dopant-dopant repulsion and vacancy-vacancy repulsion as well contribute to the so-called conductivity maximum of the ionic conductivity [1]. BaZrO3-based oxides are proto-type proton conductors. Using density-functional theory (DFT), we have investigated defect interaction and proton migration energies in Y-doped BaZrO3. The macroscopic proton conductivity was then investigated by means of KMC simulations. We discuss the resulting proton conductivities concerning special percolation pathways for protons [2]. Finally, we compare our theoretical results with experimental ones and discuss similarities and differences for oxygen ion and proton conductors. J. Koettgen, S. Grieshammer, P. Hein, B. Grope, M. Nakayama, M. Martin, Phys. Chem. Chem. Phys., 2018, 20, 14291-14321 F. Draber, C. Ader, M. Martin, submitte

Total factor productivity effects of interregional knowledge spillovers in manufacturing industries across Europe

The objective of this study is to identify knowledge spillovers that spread across regions in Europe and vary in magnitude for different industries. The study uses a panel of 203 NUTS-2 regions covering the 15 pre-2004 EU-member-states to estimate the impact over the period 1998-2003, and distinguish between five major industries. The study implements a fixed effects panel data regression model with spatial autocorrelation to estimate effects using patent applications as a measure of R&D output to capture the contribution of R&D (direct and spilled-over) to regional productivity at the industry level. The results suggest that interregional knowledge spillovers and their productivity effects are to a substantial degree geographically localised and this finding is consistent with the localisation hypothesis of knowledge spillovers. There is a substantial amount of heterogeneity across industries with evidence that two industries (electronics, and chemical industries) produce interregional knowledge spillovers that have positive and highly significant productivity effects. The study, moreover, confirms the importance of spatial autoregressive disturbance in the fixed effects model for measuring the TFP impact of interregional knowledge spillovers at the industry level.Total factor productivity, manufacturing industries, knowledge spillovers,patents, European regions, spatial econometrics