Pilot, Rollout and Monte Carlo Tree Search Methods for Job Shop Scheduling

Greedy heuristics may be attuned by looking ahead for each possible choice, in an approach called the rollout or Pilot method. These methods may be seen as meta-heuristics that can enhance (any) heuristic solution, by repetitively modifying a master solution: similarly to what is done in game tree search, better choices are identified using lookahead, based on solutions obtained by repeatedly using a greedy heuristic. This paper first illustrates how the Pilot method improves upon some simple well known dispatch heuristics for the job-shop scheduling problem. The Pilot method is then shown to be a special case of the more recent Monte Carlo Tree Search (MCTS) methods: Unlike the Pilot method, MCTS methods use random completion of partial solutions to identify promising branches of the tree. The Pilot method and a simple version of MCTS, using the $\varepsilon$-greedy exploration paradigms, are then compared within the same framework, consisting of 300 scheduling problems of varying sizes with fixed-budget of rollouts. Results demonstrate that MCTS reaches better or same results as the Pilot methods in this context.Comment: Learning and Intelligent OptimizatioN (LION'6) 7219 (2012

ORCID for Wikidata. Data enrichment for scientometric applications

Due to its numerous bibliometric entries of scholarly articles and connected information Wikidata can serve as an open and rich source for deep scientometrical analyses. However, there are currently certain limitations: While 31.5% of all Wikidata entries represent scientific articles, only 8.9% are entries describing a person and the number of entries researcher is accordingly even lower. Another issue is the frequent absence of established relations between the scholarly article item and the author item although the author is already listed in Wikidata. To fill this gap and to improve the content of Wikidata in general, we established a workflow for matching authors and scholarly publications by integrating data from the ORCID (Open Researcher and Contributor ID) database. By this approach we were able to extend Wikidata by more than 12k author-publication relations and the method can be transferred to other enrichments based on ORCID data. This is extension is beneficial for Wikidata users performing bibliometrical analyses or using such metadata for other purposes

Root cortex development is fine-tuned by the interplay of MIGs, SCL3 and DELLAs during arbuscular mycorrhizal symbiosis

Root development is a crucial process that determines the ability of plants to acquire nutrients, adapt to the substrate and withstand changing environmental conditions. Root plasticity is controlled by a plethora of transcriptional regulators that allow, in contrast to tissue development in animals, post-embryonic changes that give rise to new tissue and specialized cells. One of these changes is the accommodation in the cortex of hyperbranched hyphae of symbiotic arbuscular mycorrhizal (AM) fungi, called arbuscules. Arbuscule-containing cells undergo massive reprogramming to coordinate developmental changes with transport processes. Here we describe a novel negative regulator of arbuscule development, MIG3. MIG3 induces and interacts with SCL3, both of which modulate the activity of the central regulator DELLA, restraining cortical cell growth. As in a tug-of-war, MIG3-SCL3 antagonizes the function of the complex MIG1-DELLA, which promotes the cell expansion required for arbuscule development, adjusting cell size during the dynamic processes of the arbuscule life cycle. Our results in the legume plant Medicago truncatula advance the knowledge of root development in dicot plants, showing the existence of additional regulatory elements not present in Arabidopsis that fine-tune the activity of conserved central modules

Fünf Vorschläge für reinere Luft : Kosten-Effektivitäts-Analyse von Maßnahmen zur Reduzierung der SO2-Emissionen aus öffentlichen Kraftwerken in Baden-Württemberg

Verteuerung schwefelärmerer Kohle, bevorzugter Betrieb von Kraftwerken mit REA, vermehrter Gaseinsatz bei Mischfeuerungen, möglichst schnelle Inbetriebnahme bereits geplanter Rauchgasreinigungsanlagen sowie zwischenzeitliche Verstärkung der Stromimportmenge aus der Schweiz sind die fünf Sofortmaßnahmen, die in Baden-Württemberg eine Arbeitsgruppe aus EVU- und Landesregierungsvertretern sowie aus Wissenschaftlern als wirtschaftlich praktikabel empfiehlt, um kurzfristig die Schadstoff-Emissionen aus Kraftwerken zu verringern

Kosten und Wirksamkeit von Maßnahmen zur Reduzierung der SO2-Emissionen aus Kraftwerken in Baden-Württemberg

Die Landesregierung von Baden-Württemberg hat eine Arbeitsgruppe ins Leben gerufen, die Strategien zu einer Reduzierung der SO2-Emissionen aus öffentlichen Kraftwerken prüfen und empfehlen soll. Der Arbeitsgruppe gehörten Vorstände der großen baden-württembergischen Elektrizitätsversorgungsunternehmen, Vertreter der Landesregierung und Wissenschaftler an. Die Autoren dieses Berichts haben systemtechnische Analysen zur Unterstützung der Arbeitsgruppe durchgeführt

Costs and effectiveness of measures to reduce SO2-emissions : a decision support analysis

The damage to forests observed in the central and southern parts of the Federal Republic of Germany has increased very rapidly over the past two years. Most scientists believe that S02-and NOx-emissions are the main reasons for this damage. This demands the immediate initiation of countermeasures. Since the benefits of these measures cannot be calculated exactly, political decisions have to be made under conditions that are uncertain. The paper demonstrates how and to what extent a cost-effectiveness analysis is able to support a rational decision process under these circumstances. The investigation area is Baden-Wurrtemberg, a state situated in the southwest of the Federal Republic of Germany. First, a reference scenario is defined which describes the possible development of the electricity supply system. Then measures to reduce SO2-missions are collected and described. Measures required by law (for instance, installation of flue-gas desulphurization by July 1988), are not considered, since they are part of the reference scenario. A cost-effectiveness ratio - that is the amount of money needed to reduce the emissions by one kilogram of SO2 - is evaluated for every measure considered. Measures with a cost-effectiveness ratio that is lower than or equal to that of measures required by law are recommended. Regional electricity suppliers have agreed to put these measures into effect. Realization of these measures will reduce So2-emissions in Baden-Württemberg by approximately 25%, or 19000 t S02 per year, during the period 1984 to 1988. Experience shows that a carefully executed cost-effectiveness analysis can be a valuable input to a decision making process in an uncertain environment by evaluating and ranking the costs and effects of the SO2-reduction measures that are at our disposal

MNEs and flexible working practices in Mauritius

We compare how far companies based in Africa, India and the 'global North' operating in Mauritius adopt high-trust flexible working practices, and how these are linked to different clusters of wider labour management practice. Using comprehensive firm-level data collected in late 2011, we find that African/Indian company practices are closer to those of indigenous firms than to those of Northern companies. The different company groups operate in quite different ways but regional MNEs operate in a similar way to indigenous companies. We therefore conclude that Rugman and Verbeke’s ‘regionalization’ theory also applies to the HR field. We further find that both a relatively strategic approach to HRM and measures to develop employer-employee interdependence are, respectively, linked directly and indirectly to flexible working incidence

Modelling historical and current irrigation water demand on the continental scale

Abstract. Water abstractions for irrigation purposes are higher than for any other pan-European water use sector and have a large influence on river runoff regimes. This modelling experiment assesses historic and current irrigation water demands for different crops in five arc minute spatial resolution for pan-Europe. Two different modelling frameworks have been applied in this study. First, soft-coupling the dynamic vegetation model LPJmL with the land use model LandSHIFT leads to overestimations of national irrigation water demands, which are rather high in the southern Mediterranean countries. This can be explained by unlimited water supply in the model structure and illegal or not gauged water abstractions in the reported data sets. The second modelling framework is WaterGAP3, which has an integrated conceptual crop specific irrigation module. Irrigation water requirements as modelled with WaterGAP3 feature a more realistic representation of pan-European water withdrawals. However, in colder humid regions, irrigation water demands are often underestimated. Additionally, a national database on crop-specific irrigated area and water withdrawal for all 42 countries within pan-Europe has been set up and integrated in both model frameworks