Forecasting with time series imaging

Feature-based time series representations have attracted substantial attention in a wide range of time series analysis methods. Recently, the use of time series features for forecast model averaging has been an emerging research focus in the forecasting community. Nonetheless, most of the existing approaches depend on the manual choice of an appropriate set of features. Exploiting machine learning methods to extract features from time series automatically becomes crucial in state-of-the-art time series analysis. In this paper, we introduce an automated approach to extract time series features based on time series imaging. We first transform time series into recurrence plots, from which local features can be extracted using computer vision algorithms. The extracted features are used for forecast model averaging. Our experiments show that forecasting based on automatically extracted features, with less human intervention and a more comprehensive view of the raw time series data, yields highly comparable performances with the best methods in the largest forecasting competition dataset (M4) and outperforms the top methods in the Tourism forecasting competition dataset

Investigating white matter changes underlying overactive bladder in multiple sclerosis with diffusion MRI

Lower urinary tract symptoms (LUTS) are presented in more than 80% of multiple sclerosis (MS) patients. Current understanding of LUT control is based on studies exploring activities in grey matter (GM) and investigating functional correlations with LUTS. The relationship between white matter (WM) changes and overactive bladder (OAB) symptoms are limited to findings in small vessel disease, and the nature of the association between WM changes and OAB symptoms is poorly understood. Advanced diffusion-weighted magnetic resonance imaging (MRI) techniques provide non-invasive techniques to study WM abnormalities and correlates to clinical observations. The overarching objectives of this work are to explore WM abnormalities subtending OAB symptoms in MS, and to reconstruct the structural network underpinning the working model of lower urinary tract (LUT) control. Using Tract-Based Spatial Statistics (TBSS), OAB symptoms related WM abnormalities in MS can be identified, and a structural network subtending OAB symptoms in MS can be subsequently created. The findings of this work illustrate the correlation between OAB symptoms severity and WM abnormalities in MS. These were observed in regions in frontal lobes and non-dominant hemisphere, including corpus callosum, anterior corona radiata bilaterally, right anterior thalamic radiation, superior longitudinal fasciculus bilaterally, and right inferior longitudinal fasciculus. The structural network created for OAB symptoms in MS connected regions known to be involved in the working model of LUT control, and the network identified connectivity between insula and frontal lobe, which is the key circuit for perception of bladder fullness. Moreover, structural connectivity between insula-temporal lobe and insula-occipital lobe were observed, which may underpin changes seen in functional MRI (fMRI) studies. The novel findings of this study present WM abnormalities and structural connectivity subtending LUTS in MS with diffusion-weighted imaging (DWI). The techniques used in this work can be applied to other patterns of LUTS and other neurological diseases

Mining Data Value of Group Prediction Wisdom in the Era of Big Data

When making predictions about an uncertain event, the individual’s ability is always limited and biased. Therefore, in order to predict the outcome of the event, it is necessary to collect prediction data from different individuals to make predictions. The aggregated results of individuals are always better than most individuals, and the performance of the group is called group wisdom. However, due to information technology and space constraints, the data collects is limited under normal circumstances, time-consuming and costly, and the group’s ability to predict is limited. In big data era today, we can collect massive amounts of data that meet the forecasting requirements more quickly, aggregate these data, and through certain data processing methods, we can get the solution of the group, which is generated in this environment. The prediction of the data is often more accurate, and the predictive power of the group is greatly increased

Soil erosion and sediment yield in the upper Yangtze, China

Soil erosion and sedimentation are key environmental problems in the Upper Yangtze because of the ongoing Three Gorges Project (TGP), the largest hydro-power project in the world. There is growing concern about the rapid increase of soil erosion over the last few decades and its consequence for potential sedimentation in the reservoir. The study aims to examine controls on the spatial and temporal distributions of sediment transfer within the Upper Yangtze and the hydrological consequences of land use changes, using varied approaches at different catchment scales. First, soil erosion and sedimentation are examined using the radionuclide Cs-137 as a tracer within a small reservoir catchment in the Three Gorges Area. The results indicates that soil erosion on sloping arable land and the rates of reservoir sedimentation have been severe during the past 40 years, mainly due to cultivation on steep slopes. Changes in reservoir sedimentation rates are mainly attributed to land use changes. The suitability of the Cs-137 techniques for investigating soil erosion and sedimentation in intensely cultivated subtropical environments is also considered. The use of the technique for erosion investigation may have limitations due to the abundance of coarse soil textures, uncertainty about fallout deposition rates and the high incidence of human disturbance, but the technique shows promising perspectives for sedimentation investigation since a few dating horizons might be identified. Second, sediment and runoff measurement data for around 30 years from over 250 hydrological stations within the Upper Yangtze have been examined within a GIS framework. The dataset has been integrated with catchment characteristics derived from a variety of environmental datasets and manipulated with Arc/Info GIS. The analysis of the sediment load data has permitted identification of the most important locations of sediment sources, the shifting pattern of source areas in relation to land use change and sub-catchments exhibiting trending sediment yields corrected for hydrological variability. The study demonstrates the importance of scale dependency of sediment yield in both the identification of temporal change and the modelling of relationships between sediment yield and environmental variables, suggesting that the treatment of the scale problem is crucial for temporal-spatial studies of sediment yield

Integrated spatial decision support system for precision agriculture

Excessive application of plant nutrients and pesticides on agricultural land has resulted in both environmental degradation and economic loss to the farming community. Agricultural non-point source pollution was cited as the primary source of the water quality problems in many areas of the United States. Environmental concerns resulting from agricultural non-point source pollution has placed demands on farmers and ranchers to implement the best management practices (BMPs) to reduce the delivery of pollutants to streams and aquifers. Precision agriculture, a relatively recent crop production and agricultural management strategy holds great promise to minimize environmental pollution while to maximize economic productivity and profitability. It has benefited from rapidly evolving geospatial information technologies, such as global positing systems (GPS), geographic information systems (GIS), remote sensing (RS), and electronic sensors and intelligent controllers. However, the complexity of making routine, coherent, and cost-effective farm management decisions presents a formidable challenge to farmers. What is lacking in precision agriculture is an analytical tool that integrates these component technologies with biophysical and economic models for tactical, strategic, and policy-level decision make. In this dissertation, a decision support system called IDSSPA is developed to include modules for evaluating crop yield and chemical losses in response to site-specific management of agricultural inputs. Using this system, not only can users store, visualize, manipulate, and analyze spatial/non-spatial field experiment data, but they also can do various simulations through the easy-operated biophysical models, which take field spatial variability into account. In the system, the functionalities of the traditional models and analysis methods have been enhanced by coupling them with each other and with ArcView GIS. Uniquely designed GIS-based interfaces enable the lumped biophysical models to incorporate and represent field spatial variability. Statistical and data mining tools are also included in the system to improve analysis of field measured data and to further enhance interpretation of model simulation results. Other components incorporated into the system are as follows: The CERES-Maize plant growth model seamlessly integrated with RZWQM to provide an alternative phonologically based model for predicting growth and yield of maize (corn), and several tools for evaluating economic and ecologic risks of precision agriculture implementation. The application examples indicated that IDSSPA is a useful research and decision make tool for precision agriculture at field and watershed scales

Temporal Variations of Streamflow in a Mid-Latitude Eurasian Steppe Watershed in the Past Half Century

Previous studies either did not identify abrupt change or identified such change but did not exclude it from the detection of trend in streamflow. As a result, an overall downward trend might be erroneously detected as an upward trend because of abrupt increase, while an overall upward trend could be faked as a downward trend due to abrupt decrease. The objectives of this study were to: (1) present a methodology to analyze trend in streamflow in the presence of abrupt change; and (2) use this methodology to detect trend and extreme occurrence of streamflow in the Upper Balagaer River watershed, a mid-latitude nearly pristine precipitation-fed Eurasian steppe watershed in north China. The results indicate that streamflow abruptly decreased around 1994 and exhibited no significant trend from 1960 to 1993 but a significant decrease trend since 1994 (in particular after 1999). In addition, the occurrence of days with a low streamflow was greater after 1994, whereas the occurrence of days with a high streamflow was smaller. Further, the inclusion of the abrupt change in the analysis could compound the detection of the pre-1994 trends but had minimal influences on the detection of the post-1994 trends. These results can be representative across the Eurasian steppe region beyond the study watershed

Conflicts and order : controversies over municipal solid waste incineration in China

Au cours des dernières décennies, nous avons été témoins de la croissance des controverses relatives à l’incinération des déchets solides municipaux dans de nombreuses villes du monde. Cela est particulièrement vrai pour les grandes et moyennes villes en Chine. Diverses catégories d’acteurs, y compris l’État, les autorités locales, les acteurs du marché économique et de la société civile, tentent d’exercer leur influence sur la construction, l’extension et/ou l’opération des incinérateurs. Même si les controverses relatives à l’incinération des déchets solides municipaux abordées par le passé dans plusieurs disciplines, nous ne sommes pas en présence d’une véritable compréhension collective suffisante de la stabilité et du changement à l’échelle méso. La thèse traite de la question suivante: dans les débats et les affrontements autour de l’incinération, comment et jusqu’à quel point les interactions et les compétitions entre contestataires et adversaires contribuent-elles à définir un champ d’action stratégique où la structure industrielle et les politiques de gestion des déchets dominées par l’incinération sont remises en question ou reconduites ? Pour répondre à cette question, cette étude considère l’incinération des déchets solides municipaux en Chine sous l’angle d’un champ d’action stratégique. Elle essaie de clarifier ce qui se passe dans ce champ sous trois aspects: les acteurs, les actions stratégiques et les retombées politiques. Faisant appel à une démarche de recherche qualitative, un grand volume de données primaires et secondaires a été amassé, y compris 42 entretiens semi-structurés, 557 posts en ligne, des rapports de recherche, des documents d’archives, des rapports d’évaluation de l’impact sur l’environnement, des nouvelles en ligne, des données statistiques et des documents de politique. À l’aide de ces données, cette étude approfondi la compréhension des relations entre, d’un côté les acteurs s’opposant aux activités découlant de l’incinération – les contestataires – et, de l’autre, les adversaires dans le champ d’action stratégique, mettant en lumière leurs arguments respectifs. En outre, le processus par lequel les militants utilisent les réseaux sociaux pour la mobilisation du consensus a reçu une attention supplémentaire. De plus, cette étude a analysé l’évolution des interactions entre les militants et les décideurs politiques et a contextualisé la transformation du champ au cours des dernières décennies. Les résultats ont montré que les controverses autour de l’incinération des déchets solides municipaux sont allées au-delà des préoccupations pour les intérêts personnels et le bien-être environnemental. Cela permet d’introduire des explications plus nuancées comparativement aux discours conventionnels concernant les protestations contre l’incinération, fournissant une compréhension systématique de l’activisme local. Cette analyse exploratoire a permis également de mieux comprendre la signification politique et sociale des controverses publiques à travers des pratiques locales de gestion des déchets. Dans un sens plus large, la thèse permet de revoir les notions usuelles à l’égard des relations entre conflits et ordre.The past few decades have witnessed the growth of controversies regarding municipal solid waste (MSW) incineration in many cities around the world. This is especially true when it comes to large and medium-sized cities in China. Various categories of actors—including the state, local authorities, market actors, and the civil society—seek to exert their influence on the construction, expansion, and/or operation of incinerators. Even though the controversies over MSW incineration have been discussed across a range of disciplines in previous literature, we are not in the presence of a sufficient collective understanding of stability and change of the meso-level social order. This dissertation addresses the following question: How and to what extent do interactions and competition between pro-incineration and anti-incineration groups contributes to defining a strategic action field (SAF) where the incineration-dominated industrial structure and waste disposal policies are challenged or maintained? To answer the question, this study considers MSW incineration in China an SAF and attempts to clarify what is happening in this SAF from three aspects: actors, strategic action, and policy impacts. Based on a qualitative research design, a great volume of primary and secondary data were collected, including 42 semi-structured interviews, 557 online posts, research reports, archival materials, environmental impact assessment reports, online news, statistical data, and policy documents. With the help of collected data, this study deepened the understanding of the relationship between proponents and opponents in the field of incineration and shed light on their respective arguments. In addition, the process through which activists used social media for consensus mobilization was given additional attention. Moreover, by analyzing the dynamics of the interplay between activists and policy makers, this study revealed and contextualized the evolution of the SAF over the past few decades. The findings showed that controversies around MSW incineration had gone beyond the concerns for personal interests and environmental well-being. This allows to introduce more refined explanations compared to conventional discourses regarding anti-incineration protests and provide a more nuanced understanding of local activism. This exploratory analysis also helped to better understand the political and social significance of public controversies through local practices of MSW management. In a broad sense, this dissertation makes it possible to review the usual conceptions with regard to the relations between conflict and order