Computing by Temporal Order: Asynchronous Cellular Automata

Our concern is the behaviour of the elementary cellular automata with state set 0,1 over the cell set Z/nZ (one-dimensional finite wrap-around case), under all possible update rules (asynchronicity). Over the torus Z/nZ (n<= 11),we will see that the ECA with Wolfram rule 57 maps any v in F_2^n to any w in F_2^n, varying the update rule. We furthermore show that all even (element of the alternating group) bijective functions on the set F_2^n = 0,...,2^n-1, can be computed by ECA57, by iterating it a sufficient number of times with varying update rules, at least for n <= 10. We characterize the non-bijective functions computable by asynchronous rules.Comment: In Proceedings AUTOMATA&JAC 2012, arXiv:1208.249

Bidding for Industrial Plants: Does Winning a 'Million Dollar Plant' Increase Welfare?

Increasingly, local governments compete by offering substantial subsidies to industrial plants to locate within their jurisdictions. This paper uses a novel research design to examine the consequences of successfully bidding for a plant on county-level labor earnings, property values, and public finances. Each issue of the corporate real estate journal Site Selection includes an article titled The Million Dollar Plant that describes how a large plant decided where to locate. These articles report the county where the plant chose to locate (i.e., the 'winner'), as well as the one or two runner-up counties (i.e., the 'losers'). The losers are counties that have survived a long selection process, but narrowly lost the competition. We use these revealed rankings of profit-maximizing firms to form a counterfactual for what would have happened in the winner counties in the absence of the plant opening. We find that a plant opening is associated with a 1.5% trend break in labor earnings in the new plant's industry in winning counties (relative to losing ones) after the opening of the plant (relative to the period before the opening). Property values may provide a summary measure of the net change in welfare, because the costs and benefits of attracting a plant should be capitalized into the price of land. We find a positive, relative trend break of 1.1% in property values. Further, we fail to find any deterioration in local governments' financial position. Overall, the results undermine the popular view that the provision of local subsidies to attract large industrial plants reduces local residents' welfare.

Jumping Through Loops: On Soft Terms from Large Volume Compactifications

We subject the phenomenologically successful large volume scenario of hep-th/0502058 to a first consistency check in string theory. In particular, we consider whether the expansion of the string effective action is consistent in the presence of D-branes and O-planes. Due to the no-scale structure at tree-level, the scenario is surprisingly robust. We compute the modification of soft supersymmetry breaking terms, and find only subleading corrections. We also comment that for large-volume limits of toroidal orientifolds and fibered Calabi-Yau manifolds the corrections can be more important, and we discuss further checks that need to be performed.Comment: 57 page

Evidence of Wave Damping at Low Heights in a Polar Coronal Hole

We have measured the widths of spectral lines from a polar coronal hole using the Extreme Ultraviolet Imaging Spectrometer onboard Hinode. Polar coronal holes are regions of open magnetic field and the source of the fast solar wind. We find that the line widths decrease at relatively low heights. Previous observations have attributed such decreases to systematic effects, but we find that such effects are too small to explain our results. We conclude that the line narrowing is real. The non-thermal line widths are believed to be proportional to the amplitude of Alfven waves propagating along these open field lines. Our results suggest that Alfven waves are damped at unexpectedly low heights in a polar coronal hole. We derive an estimate on the upper limit for the energy dissipated between 1.1 and 1.3 solar radii and find that it is enough to account for up to 70% of that required to heat the polar coronal hole and accelerate the solar wind.Comment: Accepted for publication in the Astrophysical Journal, April 201

Graph Spectral Image Processing

Recent advent of graph signal processing (GSP) has spurred intensive studies of signals that live naturally on irregular data kernels described by graphs (e.g., social networks, wireless sensor networks). Though a digital image contains pixels that reside on a regularly sampled 2D grid, if one can design an appropriate underlying graph connecting pixels with weights that reflect the image structure, then one can interpret the image (or image patch) as a signal on a graph, and apply GSP tools for processing and analysis of the signal in graph spectral domain. In this article, we overview recent graph spectral techniques in GSP specifically for image / video processing. The topics covered include image compression, image restoration, image filtering and image segmentation

Sustainable supply chain management needs sustainable logistics services. The strategic role played by logistics service providers

Purpose – The purpose of this research is to examine the concept of sustainable service co-creation in triadic business relationships in logistics and supply chain management. More companies seek to develop sustainable solutions that would not be sustainable exclusively for themselves but for the supply chain they belong to. In doing that – especially when dealing with services – they may need the external support from logistics service providers (LSPs). This paper aims to explore the innovative initiatives undertaken by LSPs in triadic relationship management with their customers and suppliers while co-creating sustainable services along the supply chain. Design/methodology/approach – To investigate the research question, a systematic literature review and empirical exploratory investigation through case study will be conducted adopting the qualitative methodology, to explore trends and evolving paradigms. Findings – A literature review conducted in this paper enriches existing literature through an integration of sustainability in a viable system approach and logistics service provision, in particular, it investigates the ways in which sustainability is achieved. It is assumed that the triadic relationship among an LSP and its customers and suppliers requires significant modifications in collaboration and an innovative approach in operating procedures. Research limitations/implications – This paper is an exploratory study and limited in its scope to an example of a relationship that focuses mainly on three actors: the supplier, the LSP and the customer. However, it could be extended in terms of numbers of case studies investigated. Practical implications – The implications arising from the literature and the empirical research offer a range of current sustainable practices in the services sector. This could be a starting point for other research and company activities. Originality/value – There is little research that addresses the issue of sustainability and logistics service providers simultaneously, hence the present paper is meant to fill the gap by providing a foundation which actors of different supply chains could use as a benchmark. This study gives evidence of how logistics services may contribute to sustainable development. Key words – sustainable supply chain management, logistics service providers, viable system approach, co-creation, business relationship managemen

The value of information in a multi-agent market model

We present an experimental and simulated model of a multi-agent stock market driven by a double auction order matching mechanism. Studying the effect of cumulative information on the performance of traders, we find a non monotonic relationship of net returns of traders as a function of information levels, both in the experiments and in the simulations. Particularly, averagely informed traders perform worse than the non informed and only traders with high levels of information (insiders) are able to beat the market. The simulations and the experiments reproduce many stylized facts of stock markets, such as fast decay of autocorrelation of returns, volatility clustering and fat-tailed distribution of returns. These results have an important message for everyday life. They can give a possible explanation why, on average, professional fund managers perform worse than the market index.Comment: 11 pages, 5 figures, published in EPJ