scholarly journals Financial networks as directed cyclic graphs - draft

2014 ◽  
Vol 11 (4) ◽  
pp. 520-529 ◽  
Author(s):  
Alexander Denev

Financial networks’ study and understanding has become extremely important since the global financial meltdown in 2007-2009 when the inter-connectedness of institutions has surfaced as one of the major culprits for the magnitude of the distress. This paper aims at providing a new approach to describe and better understand the networks of institutions and their global properties. It is based on Directed Cyclic Graphs - a subset of Probabilistic Graphical Models which have already found use in other domains such as physics and computer science. The paper draws some parallels and contrasts with other studies in the field of Network Theory. It then concludes with a stylized example.

2018 ◽  
Vol 12 ◽  
pp. 53-68
Author(s):  
Mile JOVANOV ◽  
Marija MIHOVA ◽  
Bojan KOSTADINOV ◽  
Emil STANKOV

There are several International Olympiads for secondary school students (for example, mathematics, physics, chemistry, biology and informatics). These Olympiads are not just a science competition, but a means to care for talent in the particular science. The goal of this paper is to identify the necessary topics important for good results at these international contests, and to compare the contest systems for the countries in South Eastern Europe, in the field of Informatics (Computer Science), as a region that is one of the prominent world regions in the context of high results in the international competitions. Here, we provide comparison through detailed analysis of several countries, and further we present a new approach that may be used to compare the achievements of the countries based on the results that students achieved at these competitions. Finally, we present an application of this approach on the results of some of the discussed countries compared to Macedonia. We strongly believe that the paper will provide a valuable content and approach for the entities involved in the organization of the contests, to measure their results compared to other countries, to use the information for improvement, and to use their achievements to raise awareness among the government institutions and companies in order to get support from them.


Author(s):  
Arjun P. Athreya ◽  
Tanja Brückl ◽  
Elisabeth B. Binder ◽  
A. John Rush ◽  
Joanna Biernacka ◽  
...  

AbstractHeterogeneity in the clinical presentation of major depressive disorder and response to antidepressants limits clinicians’ ability to accurately predict a specific patient’s eventual response to therapy. Validated depressive symptom profiles may be an important tool for identifying poor outcomes early in the course of treatment. To derive these symptom profiles, we first examined data from 947 depressed subjects treated with selective serotonin reuptake inhibitors (SSRIs) to delineate the heterogeneity of antidepressant response using probabilistic graphical models (PGMs). We then used unsupervised machine learning to identify specific depressive symptoms and thresholds of improvement that were predictive of antidepressant response by 4 weeks for a patient to achieve remission, response, or nonresponse by 8 weeks. Four depressive symptoms (depressed mood, guilt feelings and delusion, work and activities and psychic anxiety) and specific thresholds of change in each at 4 weeks predicted eventual outcome at 8 weeks to SSRI therapy with an average accuracy of 77% (p = 5.5E-08). The same four symptoms and prognostic thresholds derived from patients treated with SSRIs correctly predicted outcomes in 72% (p = 1.25E-05) of 1996 patients treated with other antidepressants in both inpatient and outpatient settings in independent publicly-available datasets. These predictive accuracies were higher than the accuracy of 53% for predicting SSRI response achieved using approaches that (i) incorporated only baseline clinical and sociodemographic factors, or (ii) used 4-week nonresponse status to predict likely outcomes at 8 weeks. The present findings suggest that PGMs providing interpretable predictions have the potential to enhance clinical treatment of depression and reduce the time burden associated with trials of ineffective antidepressants. Prospective trials examining this approach are forthcoming.


Author(s):  
Andrés Cano ◽  
Manuel Gómez-Olmedo ◽  
Serafín Moral ◽  
Cora B. Pérez-Ariza

2017 ◽  
Vol 9 (3/4) ◽  
pp. 347-370 ◽  
Author(s):  
Flaminia Musella ◽  
Roberta Guglielmetti Mugion ◽  
Hendry Raharjo ◽  
Laura Di Pietro

Purpose This paper aims to holistically reconcile internal and external customer satisfaction using probabilistic graphical models. The models are useful not only in the identification of the most sensitive factors for the creation of both internal and external customer satisfaction but also in the generation of improvement scenarios in a probabilistic way. Design/methodology/approach Standard Bayesian networks and object-oriented Bayesian networks are used to build probabilistic graphical models for internal and external customers. For each ward, the model is used to evaluate satisfaction drivers by category, and scenarios for the improvement of overall satisfaction variables are developed. A global model that is based on an object-oriented network is modularly built to provide a holistic view of internal and external satisfaction. The linkage is created by building a global index of internal and external satisfaction based on a linear combination. The model parameters are derived from survey data from an Italian hospital. Findings The results that were achieved with the Bayesian networks are consistent with the results of previous research, and they were obtained by using a partial least squares path modelling tool. The variable ‘Experience’ is the most relevant internal factor for the improvement of overall patient satisfaction. To improve overall employee satisfaction, the variable ‘Product/service results’ is the most important. Finally, for a given target of overall internal and external satisfaction, external satisfaction is more sensitive to improvement than internal satisfaction. Originality/value The novelty of the paper lies in the efforts to link internal and external satisfaction based on a probabilistic expert system that can generate improvement scenarios. From an academic viewpoint, this study moves the service profit chain theory (Heskett et al., 1994) forward by delivering operational guidelines for jointly managing the factors that affect internal and external customer satisfaction in service organizations using a holistic approach.


2016 ◽  
Vol 11 (2) ◽  
pp. 41-54 ◽  
Author(s):  
Andres R. Masegosa ◽  
Ana M. Martinez ◽  
Hanen Borchani

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