85 research outputs found
Shareholder value creation in Japanese banking
No full textAbstractThis paper advances the study of Fiordelisi and Molyneux (2010) by examining the shareholder value efficiency and its determinants for a large sample of Japanese banks between 1999 and 2011. A new, specifically tailored measure of the Economic Value Added approach, based on the shadow price of equity, is developed in order to account for specific characteristics of the Japanese banking system. This new “shareholder value measure” is then used in a dynamic panel data model as a linear function of various bank-risk, bank-specific, and macroeconomic variables. This study finds that cost efficiency gains, credit risk and bank size are the most important factors in explaining the shareholder value creation in Japanese banking. Cost efficiency changes are also found to significantly influence cost of equity capital
Collective resilience of heterogeneous decision makers against stubborn individuals
Get PDFLAUREA MAGISTRALEUno sciame è un gruppo di agenti con conoscenze locali dell'ambiente, che collaborano coordinando le loro azioni al fine di svolgere un compito. In questo lavoro, mi concentro sul best-of-n problem, dove l'obiettivo dello sciame è il raggiungimento di un accordo sulla migliore tra n opzioni, ognuna delle quali ha una certa qualità. Mi concentro sul processo decisionale collettivo che porta al raggiungimento di un accordo comune sull'opzione migliore, il quale è guidato dallo scambio di opinioni tra gli agenti. In questa tesi, svolgo dei test sulla resilienza dello sciame quando sono presenti agenti malevoli, che disseminano disinformazioni intenzionalmente. Gli agenti malevoli che considero sono individui testardi, chiamati anche zeloti, che non cambiano mai la loro opinione nonostante la dinamica sociale. Ogni agente è in grado di avere un'opinione alla volta e questa può cambiare come risultato di interazioni sociali. Inoltre, considero diverse configurazioni comportamentali degli agenti, prima con sciami che mostrano comportamenti omogenei, dove ogni agente nello sciame segue la stessa strategia decisionale, e li combino per creare sciami eterogenei, dove le strategie decisionali sono diversificate all'interno dello sciame. La differenza principale tra questi modelli comportamentali è la quantità di informazioni sociali che ogni agente deve elaborare, dove i modelli che necessitano più informazioni sociali sono più resilienti; tuttavia, elaborare più informazioni implica avere un costo cognitivo più alto. Quindi, il punto principale di questo lavoro risiede nella combinazione di modelli comportamentali che richiedono meno informazioni sociali con altri modelli che utilizzano più informazioni sociali per trovare l'equilibrio tra resilienza e costo cognitivo. Studio la prestazione di questi sciami ibridi costruendo e analizzando modelli matematici che rappresentano questi comportamenti. Questi modelli sono composti da sistemi di equazioni differenziali ordinarie che descrivono come la popolazione si divide in sottopopolazioni composte da agenti che hanno la stessa opinione e come le dimensioni di queste sottopopolazioni evolvono nel tempo. Analizzo e comparo questi modelli per diversi valori dei parametri, come diversi numeri di zeloti e qualità delle opzioni. Analizzo prima i modelli negli sciami omogenei, al fine di comprenderne le proprietà; successivamente, li combino in sciami eterogenei. Inoltre, sviluppo metriche al fine di valutare la loro qualità e il loro costo cognitivo. I risultati mostrano che i modelli eterogenei consentono un compromesso tra prestazioni e costi, il che non è possibile nei sistemi omogenei. Per giunta, i modelli eterogenei permettono di regolare il numero di agenti che richiedono meno informazione sociale al fine di soddisfare requisiti in termini di resilienza e costo.A swarm is a group of agents with local knowledge of the environment, that collaborate, coordinating their actions in order to perform a task. In this study, I address the best-of-n problem, where the objective of the swarm is that of reaching an agreement on the best among n options, each having an associated quality. I focus on the collective decision-making process to reach a collective agreement on the best option, which is guided by the exchange of opinions among the agents. In this thesis, I test the resilience of the swarm when malicious agents, that spread misinformation purposefully, are present. The malicious agents that I consider are stubborn individuals, also named zealots, which never change their opinion regardless of social discordance.
Each agent is able to hold one opinion at a time and this opinion may change as a result of social interactions. Moreover, I consider different behavioural configurations of the agents, first with swarms that display homogeneous behaviours, where every agent within the swarm follows the same collective decision-making strategy, and combine them to form heterogeneous swarms where the collective decision-making strategies differ across agents within the swarm. The main difference between these behavioural models is the amount of social information that each agent needs to process, where models that need to process more social information are more resilient; however, processing more information implies a higher cognitive cost. Hence, the focal point of this work resides in the combination of behavioural models that require less social information with others that use more social information to understand the balance between resilience and cognitive cost. I study the performance of such hybrid swarms by building and analysing mathematical models which represent these behaviours. These models consist of a system of ordinary differential equations that describe how the population splits into sub-populations composed of agents holding the same opinion and how the size of these sub-populations evolves over time. I analyze and compare these models for different parameter values, such as different numbers of zealots and qualities of the options. I analyze the models in homogeneous swarms first, in order to understand the baseline behaviour of such systems; then, I combine them into heterogeneous swarms. I develop metrics in order to evaluate the different models in terms of how well they perform in terms of cognitive cost. The results show that heterogeneous models allow to have a trade-off between performance and cost, while this is not possible in the homogeneous models. Furthermore, heterogeneous models allow to fine tune the number of agents that require less social information in order to meet specific requirements in terms of resilience and cognitive cost
On collective behavior in C. elegans
Get PDFC. elegans is a model organism in many biological domains, such as genetics, neurophysiology, and behavioral ecology. Despite our relatively deep knowledge of the neuronal, genetic and molecular mechanisms underlying C. elegans communication, we still lack a comprehensive understanding of emergent group-level dynamics. We review the literature on collective behavior of C. elegans by categorizing works in this relatively small research field along three main axes corresponding to primary collective responses: aggregation, swarming, and collective decision-making. Through an analysis of the methods and scientific contributions of these works, we develop a critical perspective that points to important gaps in our understanding of the mechanisms underlaying the emergence of collective responses. We discuss the consequences of the lack of evidence concerning the effect of population density on the emergence of specific group dynamics, and the relatively limited knowledge related to how self-generated pheromones regulate local interactions and contribute to the emergence of group responses. We elaborate on the methodological problems of developing experimental scenarios to disentangle causal relationships between population density, pheromone-based interactions and collective responses. We propose to overcome these limitations with an interdisciplinary approach based on the use of in vivo experiments, mathematical and computer-based models
Szerbia államiságának kezdetei
Get PDFThe author describes the rising of the constitutionalism of Serbia in this paper. First he introduces the Slavic peoples and nations. The next chapters contain the history of the development of the uniform Serbian state. The author writes the political biography of the most important Serbian kings like Stefan Nemanja and Stefan Dusan "the Great". Nemanja established the state and the dynasty of the Nemanjics in the 12'h century. The golden age of the kingdom was in the middle of the le century during the rule of Stefan Dusan who became an emperor in 1346. After his death the Serbian Empire fell into pieces. The author pays attention on the legislation, the law and the jurisdiction of the state as well. Finally the Serbian Kingdom was occupied by the Turkish Empire in the 15" century
Does more (or less) lead to violence? Application of the relative deprivation hypothesis on economic inequalityinduced conflicts
Get PDFThis article employs the relative deprivation theory in order to explain the formation of violent conflicts
induced by an increase in economic inequality. By using the frustration-aggression hypothesis,
the author attempts to illustrate how the rise in inequality, caused by changed economic structure,
can be transformed into violence, often accompanied by material and human casualties. In addition
to the theoretical framework, the article relies on empirical studies carried out by using relative deprivation
as a starting point. Finally, the author observes indications that inequality-induced conflicts
could soon take place in developed and developing countries, which is why new models of development
and economic policies must be implemented and thus used as conflict-preventing mechanisms
Has God returned to Europe? The effect of different types of religiosity on European identity
Get PDFA thesis still present in Western civilization, primarily in Europe, is the thesis
of secularization. Nevertheless, according to many studies, regardless of secularization processes, religion is an important factor in individual identities.
This paper examines the relationship between European identity and religiosity. The author used empirical data from the 2017 European Values Study to
demonstrate the predictability of different types of religiosity on primordial-type European identity at the individual level. Regarding religiosity, the author tested three categories of religiosity types and their individual effect. For
this purpose, multilevel modeling was used. The findings show that religiosity
is a strong predictor of primordial-type European identity among individuals
from across Europe. Significant differences exist between the predictability of
different types of religiosity, with belief in God and very rare praying being the
most significant
Collective Robustness of Heterogeneous Decision-Makers Against Stubborn Individuals
No full textCan heterogeneity be a cost-effective solution for swarm robotics? Motivated by what we see in animal groups, especially eusocial insect colonies, that exploit behavioural heterogeneity as the cornerstone of their success, we investigate whether or not swarms of robots with different behaviours can be more cost-effective than homogeneous swarms. We focus on the process of collective decision-making where robots must achieve a consensus on the best alternative between two options with different qualities, the best-of-2 problem. We consider four behaviours from the literature where robots use rules of voter-like models to exchange and update their opinions. We study the swarm's ability to be robust to the presence of zealots, i.e., stubborn robots that do not change their opinions. Our analysis is based on mean-field models that describe the change of the sub-populations holding different opinions. We show that heterogeneous swarms can be more efficient when we include in the analysis the cost of social interactions between robots. Normally, more interactive behaviours (e.g., pooling many neighbours' opinions at each timestep rather than one per timestep) are quicker in making a decision and more robust to zealots. Heterogeneous swarms combine high performance with lower costs, as not the entire group must be highly interactive to maximise collective performance. Our results are useful when seeking a balance between making accurate collective decisions and minimising the cost of social interactions, the objective of artificial and natural swarms.</p
Collective Robustness of Heterogeneous Decision-Makers Against Stubborn Individuals
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Collective Robustness of Heterogeneous Decision-Makers Against Stubborn Individuals
No full textCan heterogeneity be a cost-effective solution for swarm robotics? Motivated by what we see in animal groups, especially eusocial insect colonies, that exploit behavioural heterogeneity as the cornerstone of their success, we investigate whether or not swarms of robots with different behaviours can be more cost-effective than homogeneous swarms. We focus on the process of collective decision-making where robots must achieve a consensus on the best alternative between two options with different qualities, the best-of-2 problem. We consider four behaviours from the literature where robots use rules of voter-like models to exchange and update their opinions. We study the swarm's ability to be robust to the presence of zealots, i.e., stubborn robots that do not change their opinions. Our analysis is based on mean-field models that describe the change of the sub-populations holding different opinions. We show that heterogeneous swarms can be more efficient when we include in the analysis the cost of social interactions between robots. Normally, more interactive behaviours (e.g., pooling many neighbours' opinions at each timestep rather than one per timestep) are quicker in making a decision and more robust to zealots. Heterogeneous swarms combine high performance with lower costs, as not the entire group must be highly interactive to maximise collective performance. Our results are useful when seeking a balance between making accurate collective decisions and minimising the cost of social interactions, the objective of artificial and natural swarms.</p
Collective Robustness of Heterogeneous Decision-Makers Against Stubborn Individuals
No full textCan heterogeneity be a cost-effective solution for swarm robotics? Motivated by what we see in animal groups, especially eusocial insect colonies, that exploit behavioural heterogeneity as the cornerstone of their success, we investigate whether or not swarms of robots with different behaviours can be more cost-effective than homogeneous swarms. We focus on the process of collective decision-making where robots must achieve a consensus on the best alternative between two options with different qualities, the best-of-2 problem. We consider four behaviours from the literature where robots use rules of voter-like models to exchange and update their opinions. We study the swarm's ability to be robust to the presence of zealots, i.e. stubborn robots that do not change their opinions. Our analysis is based on mean-field models that describe the change of the sub-populations holding different opinions. We show that heterogeneous swarms can be more efficient when we include in the analysis the cost of social interactions between robots. Normally, more interactive behaviours (e.g. pooling many neighbours' opinions at each timestep rather than one per timestep) are quicker in making a decision and more robust to zealots. Heterogeneous swarms combine high performance with lower costs, as not the entire group must be highly interactive to maximise collective performance. Our results are useful when seeking a balance between making accurate collective decisions and minimising the cost of social interactions, the objective of artificial and natural swarms.SCOPUS: cp.pinfo:eu-repo/semantics/publishe
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