The Effects of Data Imbalance Under a Federated Learning Approach for Credit Risk Forecasting

Credit risk forecasting plays a crucial role for commercial banks and other financial institutions in granting loans to customers and minimise the potential loss. However, traditional machine learning methods require the sharing of sensitive client information with an external server to build a global model, potentially posing a risk of security threats and privacy leakage. A newly developed privacy-preserving distributed machine learning technique known as Federated Learning (FL) allows the training of a global model without the necessity of accessing private local data directly. This investigation examined the feasibility of federated learning in credit risk assessment and showed the effects of data imbalance on model performance. Two neural network architectures, Multilayer Perceptron (MLP) and Long Short-Term Memory (LSTM), and one tree ensemble architecture, Extreme Gradient Boosting (XGBoost), were explored across three different datasets under various scenarios involving different numbers of clients and data distribution configurations. We demonstrate that federated models consistently outperform local models on non-dominant clients with smaller datasets. This trend is especially pronounced in highly imbalanced data scenarios, yielding a remarkable average improvement of 17.92% in model performance. However, for dominant clients (clients with more data), federated models may not exhibit superior performance, suggesting the need for special incentives for this type of clients to encourage their participation

Interpretación del cambio y la variación a través de situaciones problemas con relaciones funcionales

En este trabajo se presentan los resultados de una investigación realizada con estudiantes del grado séptimo de la Institución Educativa Antonio Lenis de la ciudad de Sincelejo, Colombia, en la cual se buscó favorecer la interpretación del cambio y la variación, mediante el trabajo con situaciones problemas contextualizadas. Se aplicó una prueba inicial, se hizo una intervención y luego se aplicó una prueba final. Del análisis de estas pruebas se concluye que la utilización de situaciones problemas contextualizadas ayudó a que los estudiantes interpretaran la variación y el cambio, permitiéndoles asignar sentido y compartir significado de los conceptos matemáticos trabajados

Intragroup genetic relatedness in two howler monkey species (Alouatta pigra and A. palliata): Implications for understanding social systems and dispersal

Social systems and dispersal patterns impact genetic variation within and between primate groups. Kinship plays a role in shaping social interactions and therefore shapes social systems. However, few studies have used molecular data to describe the degree of genetic relatedness among intragroup individuals. In this study, I analyze genetic relatedness among same-sex intragroup adults in Alouatta palliata and A. pigra, sister species that have distinct social systems, to test the hypothesis that patterns of intragroup genetic relatedness will also be distinct. Results indicate that in both species, most groups contain closely related same-sex dyads, which was unexpected for A. palliata since it has been reported that most juveniles disperse and join groups that do not contain close kin. However, the degree of intragroup relatedness seems to be more variable among A. pigra groups, whereas most same-sex adults are closely related in A. palliata groups. This suggests that dispersing individuals may use multiple strategies to join groups (i.e., coalition take overs by related males, solitary individuals joining groups that contain close relatives, etc.) or that philopatry is common in these groups. Further study including both long-term observational and genetic data is necessary to determine the degree of variation in intragroup genetic relatedness for both species within and among populations and fitness consequences of various strategies. Ecological and demographic data are also necessary to determine the importance of other factors, especially habitat fragmentation, in determining the degree of relatedness in howler monkey groups.Master of ScienceEcology and Evolutionary BiologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/99708/1/BaizMSThesis2013.pd

Ein Beitrag zur Lebensdauerabschätzung kurzglasfaserverstärkter Kunststoffbauteile

Lebensdauervorhersagen an schwingend beanspruchten kurzglasfaserverstärkten (kgfv) Kunststoffbauteilen sind äußerst komplex. Diese Werkstoffklasse weist spezielle Eigenschaften auf, die sich stark von anderen Werkstoffen unterscheiden. Den spezifischen Einflussfaktoren muss sowohl experimentell als auch numerisch Rechnung getragen werden. Die vorliegende Arbeit beschäftigt sich mit der gesamtheitlichen Lebensdauerabschätzung von kgfv Kunststoffbauteilen. Ausgehend von experimentellen und numerischen Untersuchungen wird ein Beitrag zur zuverlässigeren Lebensdauerabschätzung geleistet. Dem Berechnungskonzept zur Lebensdauerabschätzung liegt ein rein empirischer Ansatz zugrunde, der komplexe Schädigungsabläufe nicht berücksichtigt. In dieser Arbeit wird die Übertragbarkeit der Ansätze von kgfv Proben auf komplexe Kunststoffbauteile überprüft. Die primär lebensdauerbeeinflussenden Faktoren wie Temperatur und Feuchtigkeit werden an einem Kunststoffbauteil aus PA66-GF50, im Einzelnen und in ihrer Wechselwirkung zueinander, experimentell untersucht. In weiterführenden Untersuchungen werden an Proben und am Bauteil die Schädigungsmechanismen, im Kontext der äußeren Einflüsse, analysiert. Eine grundsätzliche Übereinstimmung zwischen den an Proben und den am Bauteil ermittelten Einflussfaktoren sowie Schädigungsmechanismen kann hierbei bestätigt werden. Die auf Probenergebnissen basierenden Berechnungsmodelle und Materialkennwerte sind demnach auf ein komplexes Bauteil anwendbar. Die Berechnung einer Lebensdauer unter variabler Amplitude stellt eine weitere Besonderheit der kgfv Kunststoffe dar. Auf Basis ermittelter Gaßnerlinien und unter Einbezug äußerer Umgebungsbedingungen, wird die Genauigkeit der rechnerischen Lebensdauerabschätzung infolge der linearen Schadensakkumulation nach Miner-elementar untersucht. Die ermittelten effektiven Schadenssummen können durch Korrekturverfahren die Treffsicherheit der Lebensdauerberechnung steigern. Zur Umsetzung der rechnerischen Lebensdauerabschätzung wird die klassische Methode im Sinne metallischer Werkstoffe erweitert, indem eine Berechnungskette für die Anwendung an kgfv Kunststoffbauteilen aufgebaut wird. Die Grenzen der Anwendung des Berechnungskonzepts werden systematisch an Proben und dem Demonstrationsbauteil untersucht. Es wird festgestellt, dass durch die Erweiterung der Berechnungskette konservativ zufriedenstellende Lebensdauern, an einfachen Probengeometrien bis hin zu komplexen Strukturen, vorhergesagt werden können. Die Güte der Ergebnisse steht im Zusammenhang mit den gewählten Eingangsparametern. CT-Analysen verdeutlichen den signifikanten Einfluss der Faserorientierung auf die Genauigkeit der Ergebnisse. In diesem Zusammenhang werden die Anwendungsgrenzen der rechnerischen Lebensdauerabschätzung aufgezeigt. Gemäß dem Stand der Technik können aktuelle Softwarelösungen der Füllsimulation die Faserorientierungen nicht immer korrekt vorhersagen. In diesem Kontext werden geeignete Maßnahmen aufgezeigt und das Entwicklungspotential der Berechnungsmethode diskutiert.Lifetime prediction of short glass fiber reinforced (SGFR) plastic components under cyclic loading is extremely complex. This material class has distinct properties that differ greatly from other materials. The specific influence factors must be taken into account both experimentally and numerically. This work deals with the overall life assessment of SGFR plastic components. Based on experimental and numerical investigations, a contribution is made to more reliable life assessment. The calculation concept for lifetime estimation is based on a purely empirical approach, which does not take into account complex damage processes. In this work, the transferability of the approaches from SGFR samples to complex plastic components is checked. The primary lifetime influencing factors such as temperature and humidity are experimentally investigated on a plastic component made of PA66-GF50, in detail and in their interaction with each other. In further investigations, the damage mechanisms are analyzed on samples and on the component in the context of external influences. A fundamental agreement between the influence factors and damage mechanisms determined on samples and on the component can be confirmed here. The calculation models and material properties based on sample results are therefore applicable to a complex component. The calculation of a lifetime under variable amplitude represents another peculiarity of SGFR plastics. Based on the determined Gaßnerlinien and taking into account external environmental conditions, the accuracy of the numerical lifetime estimation due to linear damage accumulation according to Miner is examined. The determined effective damage sums can increase the accuracy of the lifetime calculation by means of correction procedures. In order to implement the numerical lifetime estimation, the classical method in the sense of metallic materials is extended by building up a calculation chain for the application to SGFR plastic components. The limits of application of the calculation concept are systematically investigated on samples and on the demonstration component. It is found that the calculation chain can conservatively approximate the lifetimes of simple sample geometries to complex structures. The quality of the results is determined by the chosen input parameters. CT analyses illustrate the significant influence of fiber orientation on the accuracy of the results. In this context, the limits of application of the numerical lifetime estimation are shown. According to the state of the art, current software solutions of the fill simulation can not always correctly predict the fiber orientations. In this context, suitable measures are identified and the development potential of the calculation method is discussed

Using Road Weather Information Systems (RWIS) to optimize the Scheduling of Load Restrictions on Northern Ontario's Low-Volume Highways

Covering the Northern part of the Province, Ontario’s low-volume roads provide a link from remote resource areas to markets. Thus, preserving this transportation asset from the two main sources of pavement deterioration, namely traffic loading and the environment is extremely critical to the movement of goods and to the economy. In particular, Northern Ontario’s secondary highways are challenged by a combination of heavy, low frequency traffic loading and a high number of freeze-thaw cycles for which most of these highways have not been structurally designed. Therefore they experience environmental damage and premature traffic-induced deterioration. To cope with this issue, the Ontario Ministry of Transportation places Spring Load Restrictions (SLR) every year during spring-thaw. For economic reasons, the duration of SLRs is usually fixed in advance and is not applied proactively or according to conditions in a particular year. This rigidity in the schedule needs to be addressed, as it can translate into economic losses either when the payload is unnecessarily restricted or when pavement deterioration occurs. While the traditional approaches are usually qualitative and rely on visual observations, engineering judgment and historical records to make SLR decisions, the latest approaches resort to climatic and deflection data to better assess the bearing capacity of the roadway. The main intent of this research was to examine how the use of a predictor for frost formation and thawing could improve the scheduling of load restrictions by tracking the frost-strengthening and thaw-weakening of the pavement structure. Based on field data captured in Northern Ontario, and on a preliminary analysis that found good correlation between frost thickness in the roadway and Road Weather Information Systems (RWIS) variables, more advanced frost and thaw predictors were developed as part of this research and are presented herein. The report outlines how the model was developed, details the calculation algorithms, and proposes an empirical methodology for a systematic site-specific calibration. This research also involved several experimental and numerical tools, including the use of a Portable Falling Weight Deflectometer (PFWD) to estimate pavement strength during spring thaw, and the use of the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to simulate the impact of SLR on the performance of typical Northern Ontario low volume roads

New molecular insights about hepatocellular carcinoma behaviour and the control of cell progression

2007/2008Studio dei fattori di elongazione eucariotici EEF1A e ruolo nello sviluppo dell'epatocarcinoma. Studio del bortezomib, inibitore del proteasoma, come potenziale farmaco da impiegare per il trattamento dell'epatocarcinoma.XXI Ciclo197

La relación entre la cultura organizacional y la productividad laboral de empresas en Colombia.

El objetivo de este documento es explorar la relación que existe entre la cultura organizacional y la productividad laboral de una empresa. Con el fin de lograr dicho objetivo se realizó una revisión bibliográfica para profundizar en los conceptos y estudiar su relación. La metodología que se desarrolló incluye parte cualitativa y parte cuantitativa. En cuanto a la parte cualitativa, se realizaron entrevistas estructuradas a directivos de 3 empresas en Colombia con el fin de entender su percepción frente a esta relación. Para la parte cuantitativa se escogieron 4 empresas que durante un periodo determinado han mostrado un una mejora o desmejora notable y continua de su cultura organizacional en el ranking de The Great Place to Work. Para estas empresas se encontró la productividad laboral teniendo en cuenta las ventas anuales y el número de trabajadores. A partir de esta investigación se encontró una relación entre el impacto que tiene la cultura organizacional en la productividad laboral de una empresa. Con lo anterior, se concluyó que la cultura organizacional es un punto clave y prioritario para las empresas de hoy en día, pues es un factor que se puede utilizar para mejorar la efectividad, la productividad y la competitividad de las empresas.Resumen ; Introducción ; 1. Marco teórico ; 2. Metodología ; 3. Desarrollo ; 4. Conclusiones ; 5. Recomendaciones.Administrador de EmpresasThis document aims to explore the possible relationship between organizational culture and labor productivity in some companies. The methodology used includes a qualitative and a quantitative part. The first one mentioned consisted in developing some interviews with managers of 3 companies in Colombia in order to understand their perception of this relationship. For the quantitative part, 4 companies were chosen that during a given period have shown a remarkable and continuous improvement or deterioration of their organizational culture in the ranking of The Great Place to Work. For these companies, labor productivity was found considering annual sales and the number of workers. From this research, a relationship was found between the impact that the organizational culture has on the labor productivity of a company. With the above, it was concluded that the organizational culture is a key aspect for companies today, as it is a factor that can be used to improve productivity and competitiveness.Pregrad

Predictions of the electro-mechanical response of conductive CNT-polymer composites

We present finite element simulations to predict the conductivity, elastic response and strain-sensing capability of conductive composites comprising a polymeric matrix and carbon nanotubes. Realistic representative volume elements (RVE) of the microstructure are generated and both constituents are modelled as linear elastic solids, with resistivity independent of strain; the electrical contact between nanotubes is represented by a new element which accounts for quantum tunnelling effects and captures the sensitivity of conductivity to separation. Monte Carlo simulations are conducted and the sensitivity of the predictions to RVE size is explored. Predictions of modulus and conductivity are found in good agreement with published results. The strain-sensing capability of the material is explored for multiaxial strain states

Natural frequencies of cracked functionally graded material plates by the extended finite element method

In this paper, the linear free flexural vibration of cracked functionally graded material plates is studied using the extended finite element method. A 4-noded quadrilateral plate bending element based on field and edge consistency requirement with 20 degrees of freedom per element is used for this study. The natural frequencies and mode shapes of simply supported and clamped square and rectangular plates are computed as a function of gradient index, crack length, crack orientation and crack location. The effect of thickness and influence of multiple cracks is also studied.Comment: 38 pages, 14 figures, 10 tables; Composite Structures, 201