Features Extraction and Reconstruction of Country Risk based on Empirical EMD

AbstractIn the application of the Empirical Mode Decomposition (EMD), reconstruction to the intrinsic mode functions (IMFs) which are obtained by EMD is necessary in order to simplify analysis and make reconstruction results of more economic explanatory power. At present, there are two main reconstruction methods; one is based on the changing of data construction, represented by the fine- to-coarse method, the other one takes the correlation of the IMFs into consideration, for example, calculating the correlation between the marginal spectrums of different IMFs. In order to study the internal unity and differences between the two methods, country risk data of the BRICS countries are selected to make the empirical analysis. The results are as follows. Firstly, it is not reasonable that the residue obtained by the EMD is directly regarded as the trend of the original data. Secondly, by fine-to-coarse, all the IMFs can be reconstructed to three time scales, which are denoted as high-frequency mode, low-frequency mode and trend respectively, but explanation of these scales for the real situation is not satisfactory. At last, trend which is extracted based on the correlation of the IMF marginal spectrums can describe the basic behavior of the original data. Contrasted to fine-to-coarse, the results obtained by the second method are more reasonable

A Research on Maximum Symbolic Entropy from Intrinsic Mode Function and Its Application in Fault Diagnosis

Empirical mode decomposition (EMD) is a self-adaptive analysis method for nonlinear and nonstationary signals. It has been widely applied to machinery fault diagnosis and structural damage detection. A novel feature, maximum symbolic entropy of intrinsic mode function based on EMD, is proposed to enhance the ability of recognition of EMD in this paper. First, a signal is decomposed into a collection of intrinsic mode functions (IMFs) based on the local characteristic time scale of the signal, and then IMFs are transformed into a serious of symbolic sequence with different parameters. Second, it can be found that the entropies of symbolic IMFs are quite different. However, there is always a maximum value for a certain symbolic IMF. Third, take the maximum symbolic entropy as features to describe IMFs from a signal. Finally, the proposed features are applied to evaluate the effect of maximum symbolic entropy in fault diagnosis of rolling bearing, and then the maximum symbolic entropy is compared with other standard time analysis features in a contrast experiment. Although maximum symbolic entropy is only a time domain feature, it can reveal the signal characteristic information accurately. It can also be used in other fields related to EMD method

Comparison of machine learning and semi-quantification algorithms for (I123)FP-CIT classification: the beginning of the end for semi-quantification?

Background Semi-quantification methods are well established in the clinic for assisted reporting of (I123) Ioflupane images. Arguably, these are limited diagnostic tools. Recent research has demonstrated the potential for improved classification performance offered by machine learning algorithms. A direct comparison between methods is required to establish whether a move towards widespread clinical adoption of machine learning algorithms is justified. This study compared three machine learning algorithms with that of a range of semi-quantification methods, using the Parkinson’s Progression Markers Initiative (PPMI) research database and a locally derived clinical database for validation. Machine learning algorithms were based on support vector machine classifiers with three different sets of features: Voxel intensities Principal components of image voxel intensities Striatal binding radios from the putamen and caudate. Semi-quantification methods were based on striatal binding ratios (SBRs) from both putamina, with and without consideration of the caudates. Normal limits for the SBRs were defined through four different methods: Minimum of age-matched controls Mean minus 1/1.5/2 standard deviations from age-matched controls Linear regression of normal patient data against age (minus 1/1.5/2 standard errors) Selection of the optimum operating point on the receiver operator characteristic curve from normal and abnormal training data Each machine learning and semi-quantification technique was evaluated with stratified, nested 10-fold cross-validation, repeated 10 times. Results The mean accuracy of the semi-quantitative methods for classification of local data into Parkinsonian and non-Parkinsonian groups varied from 0.78 to 0.87, contrasting with 0.89 to 0.95 for classifying PPMI data into healthy controls and Parkinson’s disease groups. The machine learning algorithms gave mean accuracies between 0.88 to 0.92 and 0.95 to 0.97 for local and PPMI data respectively. Conclusions Classification performance was lower for the local database than the research database for both semi-quantitative and machine learning algorithms. However, for both databases, the machine learning methods generated equal or higher mean accuracies (with lower variance) than any of the semi-quantification approaches. The gain in performance from using machine learning algorithms as compared to semi-quantification was relatively small and may be insufficient, when considered in isolation, to offer significant advantages in the clinical context

Inclusion of quasi-vertex views in a brain-dedicated multi-pinhole SPECT system for improved imaging performance

With brain-dedicated multi-detector systems employing pinhole apertures the usage of detectors facing the top of the patient\u27s head (i.e., quasi-vertex views) can provide the advantage of additional viewing from close to the brain for improved detector coverage. In this paper, we report the results of simulation and reconstruction studies to investigate the impact of the quasi-vertex views on the imaging performance of AdaptiSPECT-C, a brain-dedicated stationary SPECT system under development. In this design, both primary and scatter photons from regions located inferior to the brain can contribute to SPECT projections acquired by the quasi-vertex views, and thus degrade AdaptiSPECT-C imaging performance. In this work, we determined the proportion, origin, and nature (i.e., primary, scatter, and multiple-scatter) of counts emitted from structures within the head and throughout the body contributing to projections from the different AdaptiSPECT-C detector rings, as well as from a true vertex view detector. We simulated phantoms used to assess different aspects of image quality (i.e., uniform sphere and Derenzo), as well as anthropomorphic phantoms with multiple count levels emulating clinical(123)I activity distributions (i.e., DaTscan and perfusion). We determined that attenuation and scatter in the patient\u27s body greatly diminish the probability of the photons emitted outside the volume of interest reaching to detectors and being recorded within the 15% photopeak energy window. In addition, we demonstrated that the inclusion of the residual of such counts in the system acquisition does not degrade visual interpretation or quantitative analysis. The addition of the quasi-vertex detectors increases volumetric sensitivity, angular sampling, and spatial resolution leading to significant enhancement in image quality, especially in the striato-thalamic and superior regions of the brain. Besides, the use of quasi-vertex detectors improves the recovery of clinically relevant metrics such as the striatal binding ratio and mean activity in selected cerebral structures

(I123)FP-CIT reporting: Machine Learning, Effectiveness and Clinical Integration

(I123)FP-CIT imaging is used for differential diagnosis of clinically uncertain Parkinsonian Syndromes. Conventional reporting relies on visual interpretation of images and analysis of semi-quantification results. However, this form of reporting is associated with variable diagnostic accuracy results. The first half of this thesis clarifies whether machine learning classification algorithms, used as computer aided diagnosis (CADx) tool, can offer improved performance. Candidate machine learning classification algorithms were developed and compared to a range of semi-quantitative methods, which showed the superiority of machine learning tools in terms of binary classification performance. The best of the machine learning algorithms, based on 5 principal components and a linear Support Vector Machine classifier, was then integrated into clinical software for a reporting exercise (pilot and main study). Results demonstrated that the CADx software had a consistently high standalone accuracy. In general, CADx caused reporters to give more consistent decisions and resulted in improved diagnostic accuracy when viewing images with unfamiliar appearances. However, although these results were undoubtedly impressive, it was also clear that a number of additional, significant hurdles remained, that needed to be overcome before widespread clinical adoption could be achieved. Consequently, the second half of this thesis focuses on addressing one particular aspect of the remaining translation gap for (I123)FP-CIT classification software, namely heterogeneity of the clinical environment. Introduction of new technology, such as machine learning, may require new metrics, which in this work were informed through novel methods (such as the use of innovative phantoms) and strategies, enabling sensitivity testing to be developed, applied and evaluated. The pathway to acceptance of novel and progressive technology in the clinic is a tortuous one, and this thesis emphasises the importance of many factors in addition to the core technology that need to be addressed if such tools are ever to achieve clinical adoption

Innovation, quality of life and change management in chronic health processes. Case report and evaluation of psychological variables

La tesis doctoral “Innovación, calidad de vida y gestión del cambio en procesos crónicos de la salud. Informe de casos y evaluación de variables desde el ámbito de la psicología” establece un marco de análisis e intervención relacionado con la enfermedad de Parkinson (EP), así como la aplicación de una metodología para la medición del impacto de las intervenciones. Además, ha promovido la generación de conocimiento al proponer un modelo predictivo del malestar psicológico asociado a los cuidados, contribuyendo al desarrollo teórico. Este trabajo de investigación se ha centrado en cómo afecta la EP a la calidad de vida de pacientes y cuidadores informales (CI). Se ha buscado evidencia dentro de un marco teórico de referencia y se ha tratado de aportar soluciones desde la perspectiva de la psicología a algunos problemas de salud. Por otro lado, se han fijado unos objetivos de investigación para los que se han diseñado, organizado y dispuesto una serie de recursos que han permitido obtener información sobre el malestar psicológico en CI relacionado con los cuidados a personas con EP. A continuación, se describen brevemente los estudios que constituyen esta tesis doctoral. La parte empírica desarrolla tres trabajos inéditos de investigación. En el primero, se ha estudiado la eficacia de un programa de intervención psicológica para el cuidado de personas con EP. El tratamiento a largo plazo con levodopa (L-DOPA) en pacientes con la EP provoca la aparición de discinesias. Las discinesias son un tipo de trastorno motor que consisten en una serie de movimientos involuntarios. Una vez que aparecen, suponen un problema para el paciente y constituyen un obstáculo para el futuro del tratamiento. Las estrategias actuales para evitar su aparición suelen consistir en una reducción de la dosis de L-DOPA, lo que implica una limitación en la capacidad de movimiento en estos pacientes. Este primer estudio estableció como objetivo determinar la eficacia de un tratamiento no farmacológico para el manejo de las discinesias en personas con EP. Los participantes fueron un grupo de personas (n=20) seleccionadas en el Servicio de Neurología del Hospital Universitario Reina Sofía de Córdoba, que presentaban discinesias secundarias a la toma de L-DOPA. La eficacia del tratamiento fue comprobada con un diseño cuasi experimental, con medias pre-test y post-test tanto para el grupo que recibió el tratamiento como para otro que actuó como control (n=10 grupo de tratamiento y n=10 de control). El grupo de tratamiento participó en un programa de entrenamiento en relajación muscular progresiva. La variable dependiente fue el impacto de las discinesias sobre la capacidad de las personas con EP en el desarrollo de las actividades de la vida diaria. Esta variable fue medida con el cuestionario PDYS-26. La variable independiente fue el entrenamiento en relajación muscular progresiva descrito por Bernstein y Borkovec (1973). Finalizada la fase de tratamiento, el análisis ANOVA intra-sujetos (pre-post) por inter-sujetos (tratamientocontrol) mostró diferencias significativas de interacción: F=20,36; gl 1; p<0,001; eta al cuadrado=0,53. El intervalo de confianza para el grupo de tratamiento fue de -55,6 a - 17,3, y para el grupo de control de -0,8 a 5,1 y el pre-test: F=16,67; gl 1; p=0,001; eta al cuadrado=0,47. El entrenamiento de relajación es efectivo para reducir la severidad de las discinesias, reflejando una mayor capacitación para el desarrollo de las AVD y una mejora en el bienestar del paciente con EP. En el estudio se discuten los ajustes al programa de entrenamiento. A continuación, se describió una metodología para la valoración del tratamiento, mediante la cual, se calculó el retorno social de la inversión realizada. La innovación en los servicios sanitarios afronta retos en cuanto a la generación de alternativas eficaces para las crecientes necesidades de la población, así como el desarrollo de metodologías para su valoración. Los recursos son invertidos en programas o tratamientos dirigidos a una población específica, que presenta unas necesidades concretas. Sin embargo, se espera que el desarrollo de estas acciones genere valor en la sociedad. Ese conjunto de resultados o sucesión de impactos puede ser evaluado por medio de diferentes herramientas metodológicas. El SROI (Social Return on Investment) es uno de esos instrumentos. El propósito de esta segunda parte del estudio fue determinar el retorno social de la inversión de un tratamiento psicológico basado en la evidencia. En el mapa de impacto se recogen las cinco etapas del SROI. Con el análisis realizado se logró un impacto social positivo. Cada euro invertido ofreció un retorno social neto de 2,98€. El SROI puede ofrecer información sobre el impacto social generado por las intervenciones clínicas, determinando los rendimientos tangibles obtenidos con la inversión. Hasta aquí se ha abordado la eficacia de un tratamiento psicológico en personas con la EP. Además se ha propuesto el uso de una metodología para su valoración. Este tipo de enfermedades provocan un grave problema de salud que requiere un abordaje integral dentro del ámbito familiar. La EP provoca cambios negativos en la vida de los pacientes y los familiares. Asumir de forma continuada los cuidados a personas dependientes con EP se ha vinculado con la aparición de problemas de salud para los CI. Entre ellos se encuentra la hipertensión arterial, que constituye además un factor de riesgo asociado al desarrollo de trastornos cardiovasculares. Las guías de práctica clínica de la hipertensión arterial no recogen suficiente evidencia de los tratamientos psicológicos eficaces. El objetivo de este segundo estudio fue exponer los resultados de una intervención psicológica para el tratamiento de un problema de salud relacionado con los cuidados a una persona con EP. Se describe la eficacia de un tratamiento con biofeedback para el manejo de la hipertensión arterial en un estudio de caso. Después de la fase de intervención, se observó una reducción en la tensión arterial que experimentaba subidas bruscas coincidiendo con algunas situaciones estresantes relacionadas con los cuidados. Se encontraron diferencias clínicamente relevantes respecto a los registros iniciales. La estrategia de cuidar al cuidador tiene como objetivo mejorar la propia salud y preservar el futuro de los cuidados, contribuyendo a una mejora de la calidad de vida en el ámbito familiar. En este segundo estudio se evaluó además que efecto tenía la percepción de una mejora en la propia salud, sobre algunas variables psicológicas relacionadas con los cuidados. Tras el tratamiento, se observó un cambio positivo en algunas estrategias de afrontamiento: solución de problemas (pre-test: 25, post-test: 40); búsqueda de guía y soporte (pre-test: 50, post-test: 70); aceptación/resignación (pre-test: 55, post-test: 85). Se apreció también una variación favorable en las puntuaciones recogidas en el factor de personalidad responsabilidad (pre-test: 40, post-test: 65). Los problemas de salud relacionados con la carga de los cuidados pueden tener consecuencias sobre el afrontamiento. Una reducción de los síntomas mediante habilidades para su autorregulación, puede tener un impacto positivo, contribuyendo a mejorar la calidad de vida del CI. Los hallazgos anteriores han ofrecido información sugerente acerca de cómo puede afectar la salud del cuidador a la personalidad y las estrategias de afrontamiento dentro del ámbito de los cuidados. Esta información condujo a plantear un nuevo estudio, empleando una metodología de investigación que permita obtener resultados más generalizables. Las enfermedades crónicas suponen un problema para la salud, afectando negativamente a la calidad de vida no solo de los pacientes, sino también de las personas más cercanas y en especial a aquellas que se ocupan de los cuidados. Este tipo de enfermedades puede provocar una situación de dependencia en los pacientes, lo que suele ir unido a una demanda de ayuda externa para un normal desempeño de las funciones cotidianas. En ocasiones, la implicación en los cuidados ha sido relacionada con la carga del cuidador. A pesar de los avances en relación a las variables implicadas, aun no se sabe muy bien por qué unas personas se adaptan mejor que otros a tales cargas. Mediante un estudio con un diseño de tipo ex post facto prospectivo se han descrito las principales variables implicadas en los cuidados, explorando la relación existente entre ellas. El objetivo central fue crear un modelo predictivo del malestar psicológico del CI a partir de las variables demográficas, familiares, psicológicas, así como el grado de implicación en los cuidados. El análisis de regresión múltiple ofreció un modelo donde el 57,1% (r2=0,571) de la varianza del malestar psicológico del CI podía predecirse en función del neuroticismo (0,027), la percepción de la salud del CI (0,116), el grado de implicación en los cuidados relacionados con las actividades básicas de la vida diaria (0,315), las estrategias de afrontamiento desadaptativas (0,463), las estrategias de afrontamiento adaptativas (-0,275), la discapacidad de la persona que recibe los cuidados (0,153) y el tiempo que el CI llevaba desarrollando los cuidados (- 0,008). Estos resultados respaldan las hipótesis de partida y proporcionan apoyo a la teoría existente. Los cuidados se enmarcan dentro del paradigma de la solución de conflictos, resultado determinantes la personalidad y las estrategias de afrontamiento utilizadas.Doctoral Thesis "Innovation, quality of life and change management in chronic health processes. Case report and evaluation of psychological variables" establishes a framework for analysis and intervention related to Parkinson's disease (PD), as well as the application of a methodology for measuring the outcome of interventions. In addition, it has promoted the generation of knowledge by proposing a predictive model of psychological distress associated with care, contributing to theoretical development. This research work has focused on how PD affects the quality of life of patients and caregivers. Evidence has been sought within a theoretical frame of reference and solutions have been sought from the perspective of psychology to some health problems. On the other hand, research objectives have been set for which a series of resources have been designed, organized and made available that have made it possible to obtain information on the psychological discomfort in caregivers related to the care of people with PD. The following is a brief description of the research that makes up this doctoral Thesis. Three unpublished investigations have been included. First, the efficacy of a non-pharmacological treatment for the care of people with PD has been studied. Longterm treatment with L-DOPA may cause dyskinesias. These are a type of motor disorder consisting of a series of involuntary movements. When they do occur, they are a problem for the patient and an obstacle to future treatment. Current strategies to prevent their occurrence usually consist of a reduction in the dose of L-DOPA. This implies that the ability to move is limited. The aim was to determine the efficacy of a nonpharmacological treatment for the management of dyskinesias in people with PD. The participants were a group of people with PD (n=20) selected at the Reina Sofia University Hospital in Cordoba, who presented dyskinesias secondary to taking LDOPA. The efficacy of the treatment was verified with a quasi-experimental design, with pre-test and post-test stockings for both the group that received the treatment and the control group. The treatment group participated in a progressive muscle relaxation training program. The dependent variable was the impact of dyskinesias on the ability to perform activities of daily living. This variable was measured with the PDYS-26 questionnaire. The independent variable was progressive muscle relaxation training described by Bernstein and Borkovec (1973). Once treatment was completed, the ANOVA analysis showed significant differences in interaction: intra-subject (pre-post) by inter-subject (treatment-control) F=20.36; gl 1; p<0.001; eta squared= 0.53. The confidence interval for the treatment group was -55.6 to -17.3, and for the control group -0.8 to 5.1 and the pre-test: F=16.67; gl 1; p=0.001; eta squared=0.47. We conclude that progressive muscle relaxation training is effective in reducing dyskinesias, reflecting a greater ability to perform activities of daily living and an improvement in the well-being of people with PD. Adjustments to the treatment are discussed on paper. The application of a methodology for the assessment of the social return of the investment in the treatment described was then proposed. The challenge of innovation in health services is to generate effective alternatives for the growing needs of the population, as well as the development of methodologies for their evaluation. Resources are invested in therapies for the population with specific needs. And the development of these actions is expected to generate value in society. This set of results or succession of impacts can be evaluated using different methodological tools. The SROI is one of these instruments. The purpose of this study was to determine the social return on the investment of an evidence-based psychological treatment. The analysis of a psychological intervention program applied in a group way was carried out, with a design that included pre/post-treatment measures and a control group. The impact map shows the five stages of the SROI. A positive social impact was obtained: each monetary unit invested offered a net social return of 2.98. The SROI can offer information on the social impact caused by clinical interventions, determining the tangible returns obtained with the investment. So far the efficacy of psychological treatment in people with PD has been addressed. In addition, the use of a methodology for social impact assessment has been proposed. This type of illness causes a serious health problem that requires a comprehensive approach. The role of caregiver has been associated with the emergence of health problems. Hypertension is a risk factor associated with the development of cardiovascular disorders. Clinical practice guidelines for hypertension do not collect evidence of psychological treatments. The aim was to expose the results of a psychological treatment for the improvement of the health of caregivers. The efficacy of a treatment with biofeedback for the management of hypertension is described in a case study. After the intervention phase, a reduction in blood pressure was observed during stressful situations. Differences were found with respect to baseline scores. The strategy of caring for the caregiver allows for the improvement of one's own health and also contributes to ensuring the future of care by contributing to an improvement in the quality of life. In this second study, the effect of improving one's own health on coping was also evaluated. After treatment, a positive change was observed in some coping strategies: problem solving (pre-test: 25, post-test: 40); seeking guidance and support (pre-test: 50, post-test: 70); acceptance/resignation (pre-test: 55, post-test: 85). There was also a advantageous variation in the scores collected on the personality factor responsibility (pre-test: 40, post-test: 65). Health problems related to the burden of care may have consequences on coping. A reduction of symptoms through self-regulatory skills can have a positive impact, contributing to an improvement in the quality of life of the caregiver. The above findings have provided information about how caregiver health may affect personality and coping strategies within the care setting. This information led to a new investigation. In this case, a methodology was used that allows more generalizable results to be obtained. Chronic diseases are a health problem that negatively affects the quality of life of people with PD and their families, especially caregiver. This type of disease can lead to dependence in people with PD, which is often linked to a demand for external help for the normal development of daily functions. Sometimes, the involvement in care has been related to the caregiver's burden. Despite progress in relation to the variables involved, it is still not well known why some people adapt better than others to such caregiver burden. By means of a study with an ex post facto prospective design, the main variables involved in care have been described, exploring the existing relationship between them. The aim was to create a predictive model of caregiver psychological distress, based on demographic, family, psychological variables and the degree of involvement in care. The aim was to create a predictive model of the psychological distress of the informal caregiver from demographic, family and psychological variables, as well as the degree of involvement in care. Multiple regression analysis offered a model where 57.1% (r2= 0,571) of the variance of caregiver psychological distress could be predicted as a function of Neuroticism (0,027), health perception (0,116), degree of involvement in care (0,315), non-adaptive coping strategies (0,463), adaptive coping strategies (-0,275), disability of people with PD (0,153) and duration of care (-0,008). These results support our hypotheses and provide support for the existing theory. Care is framed within the paradigm of problema solving, where coping strategies and personality play an important role