An interacting replica approach applied to the traveling salesman problem

We present a physics inspired heuristic method for solving combinatorial optimization problems. Our approach is specifically motivated by the desire to avoid trapping in metastable local minima- a common occurrence in hard problems with multiple extrema. Our method involves (i) coupling otherwise independent simulations of a system ("replicas") via geometrical distances as well as (ii) probabilistic inference applied to the solutions found by individual replicas. The {\it ensemble} of replicas evolves as to maximize the inter-replica correlation while simultaneously minimize the local intra-replica cost function (e.g., the total path length in the Traveling Salesman Problem within each replica). We demonstrate how our method improves the performance of rudimentary local optimization schemes long applied to the NP hard Traveling Salesman Problem. In particular, we apply our method to the well-known "$k$-opt" algorithm and examine two particular cases- $k=2$ and $k=3$. With the aid of geometrical coupling alone, we are able to determine for the optimum tour length on systems up to $280$ cities (an order of magnitude larger than the largest systems typically solved by the bare $k=3$ opt). The probabilistic replica-based inference approach improves $k-opt$ even further and determines the optimal solution of a problem with $318$ cities and find tours whose total length is close to that of the optimal solutions for other systems with a larger number of cities.Comment: To appear in SAI 2016 conference proceedings 12 pages,17 figure

Promoting Inquiry in Science Classrooms in European Schools : a Handbook for Tutors

In Scotland, PISCES stands for Promoting Inquiry Skills for a Curriculum for Excellence in Science. It is a CPD module for teachers of science, which has been developed in Scotland with the support of the S-TEAM project. However, this Handbook uses our international acronym in which PISCES stands for Promoting Inquiry in Science Classrooms in European Schools . It is, we believe, potentially equally as successful across Europe as it was designed around the idea of empowering teachers to think for themselves how to make their practice more-inquiry based, wherever they are. It is recognised that some school, social, policy and cultural environments may be more supportive of the idea of ‘more inquiry-based practice’ than others. PISCES empowers teachers to make small or large changes to their practice, according to those sorts of contextual factors, their own aims and how they perceive the needs of their pupils. You will note that we have been careful to use the word ‘more’ in ‘more inquiry-based.’ As befits the idea of empowerment to adapt to one’s own context, there is no single model of inquiry being ‘pushed’ here. Indeed, we count it as a measure of success of PISCES that the teachers who have participated did very different things in making their practice more inquiry-based. Strathclyde University is a leading partner in S-TEAM. Members of Strathclyde University, along with the Development Officer for Curriculum for Excellence for East Lothian, successfully developed and delivered a pilot version of PISCES as a module to a group of East Lothian teachers, in 2010/11. The module resulted in successful ‘experiments in practice’ and increased awareness of the benefits of inquiry-based teaching and learning. The same group of teachers have also taken part in a follow-up course (ARIES: Advanced Resources for Inquiry and Evaluation in Science). PISCES is a high quality CPD programme, valued by teachers and supportive of their professional self-development. It can be applied to both primary and secondary teaching, in all science subjects. Pupils benefit from learning experiences, which develop scientific inquiry skills. Feedback from participating teachers has been consistently positive

Promoting inquiry skills in Curriculum for Excellence in Science: conceptualising inquiry to improve practice

This paper describes a Scottish initiative (arising out of a EU funded development project) involving university researchers, a local authority curriculum development officer and a group of teachers interested in developing more inquiry based approaches in science education. The project is not one in which the researchers bring prescriptions from research. Rather, it is seen as a joint effort aimed at solving practitioners' conceptual and practice issues. The overall question for the teachers was, How do I (we) make our practice more inquiry based? The question for the researchers was, How do we help you (the interested science teachers) to make your practice more inquiry based? This has two sub-questions: How do we help you to conceptualise the issues? How do we help you to solve the practice problems? As it turned out, the particular group of teachers we worked with did not ask for help with practice issues, so we have not made much progress in answering the second question. Therefore, this paper will focus on the first. We seem to have been successful in helping the teachers to acquire some useful conceptual tools for thinking about and changing their practice in ways that they valued for themselves. Perhaps the answer to the second question is that researchers can help teachers to solve their practice problems by helping them to conceptualise the issues

How Should We Use Colour in Euler Diagrams?

This paper addresses the problem of how best to use colour in Euler diagrams. The choice of using coloured curves, rather than black curves, possibly with coloured fill is often made in tools that automatically draw Euler diagrams for information visualization as well as when they are drawn manually. We address the problem by empirically evaluating various different colour treatments: coloured or black curves combined with either no fill or coloured fill. By collecting performance data, we conclude that Euler diagrams with coloured curves and no fill significantly outperform all other colour treatments. Most automated layout algorithms adopt colour fill and are, thus, reducing the effectiveness of the Euler diagrams produced. As Euler diagrams can be used in a multitude of areas, ranging from crime control to social network analysis, our results stand to increase the ability of users to accurately and quickly extract information from their visualizations

Why does mutual fund performance not persist? The impact and interaction of fund flows and manager changes

This paper investigates the reasons for the lack of long-term persistence in the investment performance of actively managed equity mutual funds. We document that the responses of investors, fund managers, and investment management companies to past performance have an important impact on future performance. Conditioning on fund flows and manager changes allows us to predict future performance of both past outperforming (winner) and past underperforming (loser) funds. Recent winner funds, experiencing neither high inflows nor the departure of a skilled fund manager, outperform by 3.60 percentage points based on risk-adjusted returns in the following year, relative to winner funds suffering from both effects. We also find that the performance of the worst performing funds experiencing both the replacement of the fund manager (internal governance) and high outflows (external governance) enjoy a subsequent increase in performance of 2.40 percentage points in the following year, relative to loser funds not experiencing these effects. Among loser funds, in particular, both mechanisms appear to interact strongly.Mutual Funds; Performance Persistence; Fund Flows; Manager Turnover

Tunable far-infrared laser spectroscopy of deuterated isotopomers of Ar–H2O

Several far-infrared vibration-rotation-tunneling transitions have been measured in deuterated isotopomers of Ar–H2O for the first time. These experimental results will enable the generation of improved intermolecular potential energy surfaces for the Ar–H2O system when combined with existing microwave, far-infrared, and infrared data

Does the Orientation of an Euler Diagram Affect User Comprehension?

Euler diagrams, which form the basis of numerous visual languages, can be an effective representation of information when they are both well-matched and well-formed. However, being well-matched and well-formed alone does not imply effectiveness. Other diagrammatical properties need to be considered. Information visualization theorists have known for some time that orientation has the potential to affect our interpretation of diagrams. This paper begins by explaining why well-matched and well-formed drawing principles are insufficient and discusses why we should study the orientation of Euler diagrams. To this end an empirical study is presented, designed to observe the effect of orientation upon the comprehension of Euler diagrams. The paper concludes that the orientation of Euler diagrams does not significantly affect comprehension

Increasing external effects negate local efforts to control ozone air pollution: a case study of Hong Kong and implications for other Chinese cities.

It is challenging to reduce ground-level ozone (O3) pollution at a given locale, due in part to the contributions of both local and distant sources. We present direct evidence that the increasing regional effects have negated local control efforts for O3 pollution in Hong Kong over the past decade, by analyzing the daily maximum 8 h average O3 and Ox (=O3+NO2) concentrations observed during the high O3 season (September-November) at Air Quality Monitoring Stations. The locally produced Ox showed a statistically significant decreasing trend over 2002-2013 in Hong Kong. Analysis by an observation-based model confirms this decline in in situ Ox production, which is attributable to a reduction in aromatic hydrocarbons. However, the regional background Ox transported into Hong Kong has increased more significantly during the same period, reflecting contributions from southern/eastern China. The combined result is a rise in O3 and a nondecrease in Ox. This study highlights the urgent need for close cross-boundary cooperation to mitigate the O3 problem in Hong Kong. China's air pollution control policy applies primarily to its large cities, with little attention to developing areas elsewhere. The experience of Hong Kong suggests that this control policy does not effectively address secondary pollution, and that a coordinated multiregional program is required

Consumer attitudes towards sustainability attributes on food labels

With current concerns about climate change and the general status of the environment, there is an increasing expectation that products have sustainability credentials, and that these can be verified. Labelling is a common method of communicating certain product attributes to consumers that may influence their choices. There are different types of labels with several functions. The aim of this study is to investigate consumers‟ purchase decisions towards certain sustainability claims on food products, particularly by displaying the reduction of carbon emissions. Choice outcomes will be evaluated using Discrete Choice Modelling (DCM). Data for the study is obtained by a web-based consumer survey undertaken in the United Kingdom (UK). Results provide information on different attributes effects on consumers‟ purchase decisions, particularly their willingness to pay. This study provides information on consumers‟ attitudes that will assist industries and firms to benefit from market opportunities, in particular assessing the methods by which carbon footprinting measures can be incorporated alongside information on other sustainability criteria in product marketing.food labeling, carbon footprint, discrete choice modeling, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Environmental Economics and Policy, Food Security and Poverty, Health Economics and Policy,