scholarly journals Stability Analysis of Company Co-Mention Network and Market Graph Over Time Using Graph Similarity Measures

Author(s):  
Alexey Faizliev ◽  
Vladimir Balash ◽  
Vladimir Petrov ◽  
Alexey Grigoriev ◽  
Dmitriy Melnichuk ◽  
...  

The aim of the paper is to provide an analysis of news and financial data using their network representation. The formation of network structures from data sources is carried out using two different approaches: by building the so-called market graph in which nodes represent financial assets (e.g., stocks) and the edges between nodes stand for the correlation between the corresponding assets, by constructing a company co-mention network in which any two companies are connected by an edge if a news item mentioning both companies has been published in a certain period of time. Topological changes of the networks over the period 2005–2010 are investigated using the sliding window of six-month duration. We study the stability of the market graph and the company co-mention network over time and establish which of the two networks was more stable during the period. In addition, we examine the impact of the crisis of 2008 on the stability of the market graph as well as the company co-mention network. The networks that are considered in this paper and that are the objects of our study (the market graph and the company co-mention network) have a non-changing set of nodes (companies), and can change over time by adding/removing links between these nodes. Different graph similarity measures are used to evaluate these changes. If a network is stable over time, a measure of similarity between two graphs constructed for two different time windows should be close to zero. If there was a sharp change between the graphs constructed for two adjacent periods, then this should lead to a sharp increase in the value of the similarity measure between these two graphs. This paper uses the graph similarity measures which were proposed relatively recently. In addition, to estimate how the networks evolve over time we exploit QAP (Quadratic Assignment Procedure). While there is a sufficient amount of works studying the dynamics of graphs (including the use of graph similarity metrics), in this paper the company co-mention network dynamics is examined both individually and in comparison with the dynamics of market graphs for the first time.

Author(s):  
Ananya Nandy ◽  
Andy Dong ◽  
Kosa Goucher-Lambert

Abstract In order to retrieve analogous designs for design-by-analogy, computational systems require the calculation of similarity between the target design and a repository of source designs. Representing designs as functional abstractions can support designers in practicing design-by-analogy by minimizing fixation on surface-level similarities. In addition, when a design is represented by a functional model using a function-flow format, many measures are available to determine functional similarity. In most current function-based design-by-analogy systems, the functions are represented as vectors and measures like cosine similarity are used to retrieve analogous designs. However, it is hypothesized that changing the similarity measure can significantly change the examples that are retrieved. In this paper, several similarity measures are empirically tested across a set of functional models of energy harvesting products. In addition, the paper explores representing the functional models as networks to find functionally similar designs using graph similarity measures. Surprisingly, the types of designs that are considered similar by vector-based and one of the graph similarity measures are found to vary significantly. Even among a set of functional models that share known similar technology, the different measures find inconsistent degrees of similarity — some measures find the set of models to be very similar and some find them to be very dissimilar. The findings have implications on the choice of similarity metric and its effect on finding analogous designs that, in this case, have similar pairs of functions and flows in their functional models. Since literature has shown that the types of designs presented can impact their effectiveness in aiding the design process, this work intends to spur further consideration of the impact of using different similarity measures when assessing design similarity computationally.


1977 ◽  
Vol 9 (2) ◽  
pp. 197-214 ◽  
Author(s):  
R S Conway

Changes in regional input—output structures are studied by analyzing the temporal stability of income and output multipliers derived from the Washington State input—output tables for 1963, 1967, and 1972. One conclusion is that for impact analysis, as it is most commonly practiced, the instability of multipliers over time appears to be a minor problem. This judgment is based upon a comparison of forecasting errors in impact studies due to temporal changes in multipliers with forecasting errors arising from other aspects of the impact estimating procedure. The implication is that regional analysts should reassess the commonly felt need to update tables on a regular basis.


Crisis ◽  
2011 ◽  
Vol 32 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Friedrich Martin Wurst ◽  
Isabella Kunz ◽  
Gregory Skipper ◽  
Manfred Wolfersdorf ◽  
Karl H. Beine ◽  
...  

Background: A substantial proportion of therapists experience the loss of a patient to suicide at some point during their professional life. Aims: To assess (1) the impact of a patient’s suicide on therapists distress and well-being over time, (2) which factors contribute to the reaction, and (3) which subgroup might need special interventions in the aftermath of suicide. Methods: A 63-item questionnaire was sent to all 185 Psychiatric Clinics at General Hospitals in Germany. The emotional reaction of therapists to patient’s suicide was measured immediately, after 2 weeks, and after 6 months. Results: Three out of ten therapists suffer from severe distress after a patients’ suicide. The item “overall distress” immediately after the suicide predicts emotional reactions and changes in behavior. The emotional responses immediately after the suicide explained 43.5% of the variance of total distress in a regression analysis. Limitations: The retrospective nature of the study is its primary limitation. Conclusions: Our data suggest that identifying the severely distressed subgroup could be done using a visual analog scale for overall distress. As a consequence, more specific and intensified help could be provided to these professionals.


2010 ◽  
Vol 31 (2) ◽  
pp. 68-73 ◽  
Author(s):  
María José Contreras ◽  
Víctor J. Rubio ◽  
Daniel Peña ◽  
José Santacreu

Individual differences in performance when solving spatial tasks can be partly explained by differences in the strategies used. Two main difficulties arise when studying such strategies: the identification of the strategy itself and the stability of the strategy over time. In the present study strategies were separated into three categories: segmented (analytic), holistic-feedback dependent, and holistic-planned, according to the procedure described by Peña, Contreras, Shih, and Santacreu (2008) . A group of individuals were evaluated twice on a 1-year test-retest basis. During the 1-year interval between tests, the participants were not able to prepare for the specific test used in this study or similar ones. It was found that 60% of the individuals kept the same strategy throughout the tests. When strategy changes did occur, they were usually due to a better strategy. These results prove the robustness of using strategy-based procedures for studying individual differences in spatial tasks.


2013 ◽  
Vol 44 (6) ◽  
pp. 380-389 ◽  
Author(s):  
Sabine Förderer ◽  
Christian Unkelbach

Evaluative conditioning (EC) refers to valence changes in neutral stimuli (CSs) through repeated pairing with liked or disliked stimuli (USs). The present study examined the stability of EC effects in the course of 1 week. We investigated how this stability depends on memory for US valence and US identity. We also investigated whether CSs evaluations occurring immediately after conditioning (i.e., evaluative consolidation) are necessary for stable EC effects. Participants showed stable EC effects on direct and indirect measures, independent of evaluations immediately after conditioning. EC effects depended on memory for US valence but not for US identity. And although memory decreased significantly over time, EC effects remained stable. These data suggest that evaluative consolidation is not necessary, and that conditioned preferences and attitudes might persist even when people do not remember the concrete source anymore.


1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.


Author(s):  
Olena Pikaliuk ◽  
◽  
Dmitry Kovalenko ◽  

One of the main criteria for economic development is the size of the public debt and its dynamics. The article considers the impact of public debt on the financial security of Ukraine. The views of scientists on the essence of public debt and financial security of the state are substantiated. An analysis of the dynamics and structure of public debt of Ukraine for 2014-2019. It is proved that one of the main criteria for economic development is the size of public debt and its dynamics. State budget deficit, attracting and using loans to cover it have led to the formation and significant growth of public debt in Ukraine. The volume of public debt indicates an increase in the debt security of the state, which is a component of financial security. Therefore, the issue of the impact of public debt on the financial security of Ukraine is becoming increasingly relevant. The constant growth and large amounts of debt make it necessary to study it, which will have a positive impact on economic processes that will ensure the stability of the financial system and enhance its security.


1997 ◽  
Vol 36 (4II) ◽  
pp. 947-957 ◽  
Author(s):  
Shahrukh Rafi Khan

This paper has a two-fold objective: first, to examine the terms on which Pakistan receives aid and whether its debt situation is sustainable, and second, to examine the impact of aid and debt on economic growth. It is found that there is little encouraging that can be said about how the terms on which Pakistan has received aid over time have changed, and its current debt situation is not sustainable. Also reported is the analysis done elsewhere which shows that aid has a negative (Granger) causal impact on GDP, and aid has a robust negative impact on economic growth after controlling for supplyside shocks. We provide various reasons for this negative association.


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