Yes / This paper estimates liquidity dynamics between virtual and real assets from multiple dimensions, namely market capacity, transaction cost and market efficiency. The data covers transaction information of crypto markets and four equity exchanges (US, UK, EU and Japan) between January 2019 and December 2022. The first result shows a two-way liquidity risk feedback loop between virtual and real markets, and the second result confirms dynamic liquidity interactions between them. The US market is identified as a transmitter rather than a receiver of liquidity risk but may not escape cumulative liquidity shocks.

The central issue of this thesis is investigating the eventuality of systemic break- downs in the international financial system through examining systemic depen- dence between bank and insurance sectors. Standard models of systemic risk often use correlation of stock returns to evaluate the magnitude of intercon- nectedness between financial institutions. One of the main drawbacks of this approach is that it is oriented towards observations occurring along the central part of the distribution and it does not capture the dependence structure of outlying observations. To account for that, we use methodology which builds on the Extreme Value Theory and is solely focused on capturing dependence in extremes. The analysis is performed using the data on stock prices of the EU largest banks and insurance companies. We study dependencies in the pre- crisis and post-crisis period. The objective is to discover which sector poses a higher systemic threat to the international financial stability. Also, we try to find empirical evidence about an increase in interconnections in recent post- crisis years. We find that in both examined periods systemic dependence in the banking sector is higher than in the insurance sector. Our results also in- dicate that extremal interconnections in the respective sectors increased,...

Linkages between economic agents in form of financial assets might contribute to transmission of shocks between different parts of the economy. Aim of this thesis is to enrich the ongoing discussion about the spread of contagion through the economy. We provide an analysis of financial interlinkages in the Czech economy and using the contingent claims analysis (CCA) model we attempt to quantify risks in the system that that are implied by the existence of these linkages. We use different techniques within the framework of the model to obtain various indicators that can be used to assess stability of the system. Using simulations we find that size of losses due to riskiness of debt depends strongly on the origin of a shock and it is higher for shocks originating in the household sector than for shocks originating in the sector of the non-financial corporations. We also find that size of a decrease in capital of the banking sector needed to cause a distress in the system as relatively high and stable in time. JEL Classification E01, E44, G01, G12, G20 Keywords Balance sheet contagion, financial accounts, network models, contingent claims analysis, systemic risk Author's e-mail josef.brechler@gmail.com Supervisor's e-mail michal.hlavacek@cnb.cz

Cette thèse est articulée autour de trois risques financiers que sont : la liquidité, la contagion et le risque systémique. Ces derniers sont au centre de toutes les attentions depuis la crise de 2007-08 et resteront d’actualité à la vue des évènements que rencontrent les marchés financiers. Le premier chapitre de cette thèse présente un facteur de liquidité de financement obtenu par l’interprétation d’un phénomène de contagion en termes de risque de liquidité de marché. Nous proposons dans le second chapitre, une méta-mesure de cette liquidité de marché. Cette dernière tient compte de l’ensemble des dimensions présentes dans la définition de la liquidité en s’intéressant à la dynamique de plusieurs mesures de liquidité simultanément. L’objectif du troisième chapitre est de présenter une modélisation des rendements du marché permettant la prise en compte de la liquidité de financement dans l’estimation de la DCoVaR. Ainsi, ce travail propose une nouvelle mesure du risque systémique ayant un comportement contracyclique. Pour finir, nous nous intéressons à l’hypothèse de non-linéarité de la structure de dépendance entre les rendements de marché et ceux des institutions financières. Au cœur de la mesure du risque systémique, cette hypothèse apparait contraignante puisqu’elle n’a que peu d’impact sur l’identification des firmes les plus risquées mais peut compliquer considérablement l’estimation de ces mesures. / The aim of this thesis is to improve the management of financial risks through the employment of econometric methods. We focus on liquidity (market and funding), contagion and systemic risk, which have attracted a particularly large interest in the last years of financial turmoil. Firstly, we construct a funding liquidity factor based on the contagion effects that market liquidity risks encounter. This procedure can be useful to provide a better management of the liquidity mismatch among the assets and liabilities of a fund. Secondly, we propose a meta-measure of liquidity which incorporates multiple liquidity measures through the use of a conditional correlation model. As a result, we are able to detect drastic liquidity problems by using a single measure. Thirdly, we propose a new modeling framework for financial returns by adding an extra component related to funding liquidity to the standard DCoVaR model. In this way we obtain a countercyclical measure of systemic risk. Finally, we study to which extent a change in the estimation method affects the identification of systemically relevant Financial Institutions. In particular, the most popular measures aim at capturing the nonlinearity of the dependence structure between financial firms and market returns. We show, however, that similar results can be obtained by simply assuming a linear dependence, which can also largely simplify the estimation.

Considérant les fragilités d’une union monétaire hétérogène, ainsi que l’incapacité de la politique monétaire unique pour stabiliser les cycles financiers nationaux, des nouveaux outils pour sauvegarder la stabilité financière sont de rigueur dans l’Union Economique et Monétaire (UEM). En réponse à la crise financière, les économies avancées ont fortifié la boite à outils avec l’approche macroprudentielle à la réglementation prudentielle ; à savoir la pratique de se servir des instruments prudentiel dans le but de protéger la santé du système financier dans sa globalité et l’économie réelle, et plus seulement la santé des banques individuellement. La politique macroprudentielle porte sur ses épaules la responsabilité de maîtriser le risque systémique dans l’Union, mais les hétérogénéités nationales qui la caractérisent entraînent des redoutables défis. Cette thèse a comme but d’enrichir le débat en examinant comment les hétérogénéités macrofinancières et institutionnelles peuvent conditionner la conduite des politiques macroprudentielles. Il s’agit d’un sujet souvent abordé dans la littérature macroéconomique d’après-crise, mais la réflexion est souvent fondée sur des prémisses ne prenant pas compte des complexités inhérentes aux concepts fondamentaux, tels que la stabilité financière elle-même. Plutôt que construire des modèles davantage sophistiqués visant à incorporer toutes les dimensions du phénomène, il est possible d’améliorer l’exercice de modélisation en portant en réévaluant les bases conceptuelles. Pour cette raison, le premier chapitre est dévoué à un survol critique de la littérature dans lequel on identifie plusieurs points de tension souvent ignorés, puis on les interprète dans le contexte de l’UEM. Sur la base des enseignements du chapitre I, le chapitre II aborde la question de s’il est souhaitable que les régulateurs se soucient de stabiliser le cycle financier national en présence d’effets de report transfrontaliers, tel que dans le régime en vigueur. Dans ce but, on se sert d’un modèle statique Néo-Keynésien à deux pays où l’utilisation du coussin de fonds propres contracyclique dans le cœur nuit à la stabilité financière de la périphérie via le marché interbancaire. En comparant une règle de stabilisation nationale à un régime où le régulateur du cœur internalise les effets de report, on cible des scénarios où le statu quo se révèle sous-optimal. Finalement, le chapitre III s’intéresse aux importantes divergences institutionnelles qui existent entre les régulateurs nationaux. En examinant l’information officielle, ainsi que les évaluations du FMI et du FSB, on documente les différences qualitatives dans le cadre de gouvernance à travers six axes : mécanismes de coordination, complétude des instruments, indépendance, fluidité du processus de décision, force du mandat légal, degré de transparence et recours à la communication. Sachant que les caractéristiques institutionnelles affectent la vitesse de réaction, on propose un index synthétique comparatif pour capturer quantitativement comment ces divergences institutionnelles sont susceptibles d’influencer le biais à l’inaction. On trouve que les pays sont inégalement protégés contre le biais d’inaction, mais qu’il existe différentes approches possibles pour créer des cadres de gouvernance résilients. / Given the fragilities of a heterogenous monetary union and the inability of the single monetary policy to lean against the wind of national financial cycles, new policies to defend financial stability in the European Monetary Union (EMU) are of the upmost importance. In response global financial crisis, advanced economies have supplemented their policy arsenal with a macroprudential approach to financial regulation, the practice of using prudential regulation to protect the health of the financial system and the economy as a whole, rather than just the health of individual institutions. Policymakers have unambiguously placed the task of containing systemic financial risk on the shoulders of macroprudential policy, but the national heterogeneities that characterize the Euro area pose significant challenges. The purpose of this thesis dissertation is to enrich the debate surrounding Euro area macroprudential policy by exploring how macrofinancial and institutional heterogeneity can condition its proper conduct. Macroprudential policy is a popular subject in post-crisis macroeconomics, but analysis is often built on premises that fail to acknowledge the complexities inherent to its most basic concepts, such as financial stability itself. Rather than building ever-more complex models that aim to incorporate all the dimensions of the phenomenon, the problem can be addressed by conducting a critical reflection on the field’s conceptual bases before formulating a model’s assumptions. In the first chapter, we conduct a critical review of the literature and identify several points of tension, interpreting their implications for the Euro area case. Based on the insights of chapter I, chapter II revisits the question of whether it is ideal for regulators to keep a narrow focus on national financial stabilization in the presence of cross-border spillovers, as is currently done. To do so, we build a static two-country New-Keynesian model where countercyclical capital regulation in the core affects financial stability in the periphery through the interbank market. By comparing national stabilization rules to a regime where the core regulator internalizes the spillover, we identify scenarios where the status quo is suboptimal. Finally, chapter III examines the significant institutional differences that exist among EMU national regulators. By reviewing official information , as well as assessment reports from the IMF and the FSB; we map the qualitative differences of national governance frameworks across six dimensions: presence of coordination mechanisms, completeness of instruments, independence, decision-making expeditiousness, strength of the legal mandate, use of communication and transparency. Given that institutional characteristics influence reactivity, we aim to quantify how this institutional heterogeneity affects the vulnerability to inaction bias through a comparative synthetic index. We find that countries are unequally protected against inaction bias, but there are several possible approaches to building robust governance frameworks.

As crises financeiras são processos de perdas decorrentes do mecanismo do mercado financeiro. Elas afetam as instituições do sistema financeiro e por meio do processo de contágio se espalham por ele, algumas vezes analogamente ao efeito dominó. Este processo pode levar muitas instituições financeiras saudáveis a se tornarem insolventes. Isso acontece porque os agentes econômicos estão interligados por meio de relações contratuais e se tornam dependentes uns aos outros. O risco sistêmico pode ser entendido como o risco de uma grande perda em um sistema. O presente trabalho tem como objetivo utilizar as propriedades de um modelo de contágio, proposto para estudar os efeitos da propagação de crises financeiras, bem como a mensuração do risco sistêmico no sistema interbancário. Este problema foi investigado considerando três diferentes topologias de rede: Erdös-Rényi, Livre de Escala (ou Scale-Free) e Interbancária Empírica. A escolha destas topologias foi pelo fato de que duas delas - Livre de Escala e Interbancária Empírica - podem emular o sistema bancário real e a de Erdös-Rényi ter sido utilizada em diversos modelos da literatura. Cada nó representa um banco que possui balanço patrimonial constituído de passivos (patrimônio líquido, empréstimos e depósitos) e ativos (empréstimos, títulos e valores mobiliários). Foi analisada a influência da alavancagem do sistema, da probabilidade inicial de default e do número de clusters da rede Interbancária Empírica. O risco sistêmico foi medido utilizando o Indicador de Risco Sistêmico, o Índice de Risco Sistêmico e o VaR Sistêmico. Mostrou-se que as redes Livres de Escala são mais robustas em relação aos ataques aleatórios evitando o aumento da inadimplência. O aumento abrupto do impacto causados pela crise acontece devido ao aumento do grau de alavancagem do sistema. O número de clusters da rede Interbancária Empírica impacta a robustez do sistema. O modelo reproduz o resultado conhecido como Muito Interconectado para Falhar, que é quando bancos mais interconectados oferecem maior risco ao sistema. / The financial crises are processes of losses arising from financial market mechanism. They affect the institutions of the financial system by the process of contagion. Sometimes it is equal to the domino effect. This process can make many healthy financial institutions become insolvents. It happens because economic agents are interconnected through contractual relations and become dependent on each other. Systemic risk can be understood as the risk of a huge loss in a system. The present work aims to study the properties of a contagion model proposed to study the effects of the spread of financial crises, as well as the measurement of systemic risk in the interbank system. This problem was investigated considering three different network topologies: Erdös-Rényi, Scale-Free and Empirical Interbank. The choice of these topologies was made by the fact that two of them - Scale-Free and Empirical Interbank - may emulate the real banking system and Erdös-Rényi has been used in several models in the literature. Each node is a bank and consists on a balance sheet split as liabilities (equity, borrowings and deposits) and assets (lendings, bonds and securities). It was analyzed the influence of the coefficient of leverage, the influence of the initial probability of default and the influence of the number of clusters on the Empirical Interbank. The systemic risk was measured using the Systemic Risk Indicator, Systemic Index and Systemic Value at Risk. It was shown that Scale-Free networks are more robust against random attacks, avoiding increases in the number of defaults. The abrupt increase in the impact caused by the crisis happens due to the increase in coefficient of leverage. The number of clusters on Empirical Interbank network impacts the robustness of the system. The model reproduces the result known as Too Interconnected to Fail, that is, banks more interconnected offer higher risk to the system.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2017-04-11T12:02:13Z No. of bitstreams: 1 Carlos Alberto Gentil Junior.pdf: 672614 bytes, checksum: 08d8dba09d1898f41f86031858a326d7 (MD5) / Made available in DSpace on 2017-04-11T12:02:13Z (GMT). No. of bitstreams: 1 Carlos Alberto Gentil Junior.pdf: 672614 bytes, checksum: 08d8dba09d1898f41f86031858a326d7 (MD5) Previous issue date: 2017-03-13 / The international financial market deregulation and liberalization from the 1980s onwards has allowed change in the rules about the financial regulation and, consequently, increasing the development of more complex fianancial innovation. However the several financial crisis that reached the international financial system, mainsly, after 2007, demonstrated that regulation based exclusively on the mainstream economic thought of the Market failure was not prepared to avoid systemic risk. The purpose of this reseacrh is to demonstrate that the tools adopted by international financial regulation, based only on the Market failures theory, are not enough to avoid the systemic risk from of fragility and instability of the system. Thus, for that this regulation to be effective in prevention of the new financial crisis from systemic risks, is necessary its review based in theoretical foundations created by Keynes e developed by post-keynesian authors, mainly by MInsky, who has been forgotten by neoclassical theory, such as uncertainties and liquidity preference / A desregulamentação e a liberalização do mercado financeiro internacional a partir dos anos 1980 permitiram a alteração de regras da regulação financeira e consequentemente fomentaram o desenvolvimento de instrumentos financeiros cada vez mais complexos. Entretanto as diversas crises financeiras que atingiram o sistema financeiro internacional, principalmente aquela ocorrida a partir de 2007, demonstraram que a regulação baseada exclusivamente no pensamento econômico mainstream das falhas de mercado não estava preparada para combater o chamado risco sistêmico. O objetivo desta pesquisa é mostrar que as medidas adotadas pela regulação financeira internacional, baseadas somente na teoria das falhas de mercados, são insuficientes para evitar os riscos sistêmicos decorrentes da fragilidade e da instabilidade do sistema. Dessa forma, para que essa regulação tenha eficácia na mitigação de novas crises financeiras decorrentes dos riscos sistêmicos, é essencial sua reavaliação com base nos fundamentos teóricos elaborados por Keynes e desenvolvidos por autores pós-keynesianos, dentre os quais se destaca Minsky, negligenciados pela teoria neoclássica, tais como a incerteza não probabilística e a preferência pela liquidez

O estudo econômico e financeiro vem se modificando e buscando novas metodologias. Desde a crise que se iniciou com os \"subprimes\" nos Estados Unidos em 2008 e se espalhou para as economias de todo o mundo, novas discussões de como ela poderia ter sido evitada e qual caminho deveriam os países seguir para sair da estagnação já surgem no mundo acadêmico em direção ao estudo da complexidade. Em termos econômicos, algumas críticas feitas ao estudo da economia tradicional, principalmente atribuídas ao excesso de restrições utilizados nos modelos, podem ser agora afrouxadas, uma a uma, através de modelagens baseadas em agentes. Já no entendimento e controle do risco financeiro, redes complexas prestam fundamental distinção. Os modelos até então utilizados para controle de riscos no mercado financeiro não levam em consideração o risco global, porém apenas o risco local. Muitas teorias sobre a diminuição do risco através da diversificação são aceitas e realmente produzem sistemas mais estáveis, porém com pouca resiliência, ou seja, o número de crises diminui, porém as que ocorrem são muito mais graves. Este trabalho sugeriu um modelo baseado em agentes, onde um sistema econômico simples foi construído, para ser capaz de gerar crises. Este modelo formado por firmas e demanda estocástica, utiliza bancos para simular o mercado financeiro. Tais bancos estão conectados entre si através de uma rede interbancária. Para testar os efeitos de risco sistêmico, foram realizados três testes. No primeiro aumentou-se a alavancagem máxima permitida e os bancos conseguiram obter mais lucro e maior crescimento, porém a partir de certo patamar o sistema entrou em colapso, com frequente crises. No segundo aumentou-se a conectividade média e os bancos também obtiveram maior lucro, porém com crises muito mais profundas. No aumento do índice de cluster da rede interbancária, assim como nos dois primeiros testes os bancos conseguiram maior crescimento, porém agora sem os mesmos efeitos indesejáveis causados pelo aumento do risco. / Economic and financial studies have been changing and searching new methodologies. Since the 2008 subprime crisis, which spread into economies around the globe, new discussions on how it could have been prevented, and paths which countries should follow to emerge from stagflation have been discussed by the academic world towards the complexity subject. In economic terms, some of the criticism of neoclassic economics, mainly due to excessive constrains used by its models, can now be eased, one by one, through agent based modeling. Regarding financial risk understanding and control, complex networks assume fundamental distinction. Models applied so far in financial market risk control dont consider global risk, but only the local one. Many theories on risk diversification are accepted and indeed produce more stable systems, although with little resilience, which means smaller number of crisis, but when it does occur, are more serious ones. This paper suggested an agent based model, using a simple economic system capable of generating crisis. This model was constituted by firms and stochastic demand, using banks to simulate the financial market. These banks were connected though a banking network. In order to test systemic risk, the model performed three tests. First, the maximum leverage allowed was increased and banks were able to achieve higher profits and growth, but from a certain level, the system collapsed with frequent crisis. Second, the average connectivity was increased and banks obtained higher profits, however with more severe crisis. Finally, increasing banking network cluster index, similarly to the first two tests, banks achieved higher growth, but without the undesirable effects caused by risk increase.

O estudo econômico e financeiro vem se modificando e buscando novas metodologias. Desde a crise que se iniciou com os \"subprimes\" nos Estados Unidos em 2008 e se espalhou para as economias de todo o mundo, novas discussões de como ela poderia ter sido evitada e qual caminho deveriam os países seguir para sair da estagnação já surgem no mundo acadêmico em direção ao estudo da complexidade. Em termos econômicos, algumas críticas feitas ao estudo da economia tradicional, principalmente atribuídas ao excesso de restrições utilizados nos modelos, podem ser agora afrouxadas, uma a uma, através de modelagens baseadas em agentes. Já no entendimento e controle do risco financeiro, redes complexas prestam fundamental distinção. Os modelos até então utilizados para controle de riscos no mercado financeiro não levam em consideração o risco global, porém apenas o risco local. Muitas teorias sobre a diminuição do risco através da diversificação são aceitas e realmente produzem sistemas mais estáveis, porém com pouca resiliência, ou seja, o número de crises diminui, porém as que ocorrem são muito mais graves. Este trabalho sugeriu um modelo baseado em agentes, onde um sistema econômico simples foi construído, para ser capaz de gerar crises. Este modelo formado por firmas e demanda estocástica, utiliza bancos para simular o mercado financeiro. Tais bancos estão conectados entre si através de uma rede interbancária. Para testar os efeitos de risco sistêmico, foram realizados três testes. No primeiro aumentou-se a alavancagem máxima permitida e os bancos conseguiram obter mais lucro e maior crescimento, porém a partir de certo patamar o sistema entrou em colapso, com frequente crises. No segundo aumentou-se a conectividade média e os bancos também obtiveram maior lucro, porém com crises muito mais profundas. No aumento do índice de cluster da rede interbancária, assim como nos dois primeiros testes os bancos conseguiram maior crescimento, porém agora sem os mesmos efeitos indesejáveis causados pelo aumento do risco. / Economic and financial studies have been changing and searching new methodologies. Since the 2008 subprime crisis, which spread into economies around the globe, new discussions on how it could have been prevented, and paths which countries should follow to emerge from stagflation have been discussed by the academic world towards the complexity subject. In economic terms, some of the criticism of neoclassic economics, mainly due to excessive constrains used by its models, can now be eased, one by one, through agent based modeling. Regarding financial risk understanding and control, complex networks assume fundamental distinction. Models applied so far in financial market risk control dont consider global risk, but only the local one. Many theories on risk diversification are accepted and indeed produce more stable systems, although with little resilience, which means smaller number of crisis, but when it does occur, are more serious ones. This paper suggested an agent based model, using a simple economic system capable of generating crisis. This model was constituted by firms and stochastic demand, using banks to simulate the financial market. These banks were connected though a banking network. In order to test systemic risk, the model performed three tests. First, the maximum leverage allowed was increased and banks were able to achieve higher profits and growth, but from a certain level, the system collapsed with frequent crisis. Second, the average connectivity was increased and banks obtained higher profits, however with more severe crisis. Finally, increasing banking network cluster index, similarly to the first two tests, banks achieved higher growth, but without the undesirable effects caused by risk increase.

As crises financeiras são processos de perdas decorrentes do mecanismo do mercado financeiro. Elas afetam as instituições do sistema financeiro e por meio do processo de contágio se espalham por ele, algumas vezes analogamente ao efeito dominó. Este processo pode levar muitas instituições financeiras saudáveis a se tornarem insolventes. Isso acontece porque os agentes econômicos estão interligados por meio de relações contratuais e se tornam dependentes uns aos outros. O risco sistêmico pode ser entendido como o risco de uma grande perda em um sistema. O presente trabalho tem como objetivo utilizar as propriedades de um modelo de contágio, proposto para estudar os efeitos da propagação de crises financeiras, bem como a mensuração do risco sistêmico no sistema interbancário. Este problema foi investigado considerando três diferentes topologias de rede: Erdös-Rényi, Livre de Escala (ou Scale-Free) e Interbancária Empírica. A escolha destas topologias foi pelo fato de que duas delas - Livre de Escala e Interbancária Empírica - podem emular o sistema bancário real e a de Erdös-Rényi ter sido utilizada em diversos modelos da literatura. Cada nó representa um banco que possui balanço patrimonial constituído de passivos (patrimônio líquido, empréstimos e depósitos) e ativos (empréstimos, títulos e valores mobiliários). Foi analisada a influência da alavancagem do sistema, da probabilidade inicial de default e do número de clusters da rede Interbancária Empírica. O risco sistêmico foi medido utilizando o Indicador de Risco Sistêmico, o Índice de Risco Sistêmico e o VaR Sistêmico. Mostrou-se que as redes Livres de Escala são mais robustas em relação aos ataques aleatórios evitando o aumento da inadimplência. O aumento abrupto do impacto causados pela crise acontece devido ao aumento do grau de alavancagem do sistema. O número de clusters da rede Interbancária Empírica impacta a robustez do sistema. O modelo reproduz o resultado conhecido como Muito Interconectado para Falhar, que é quando bancos mais interconectados oferecem maior risco ao sistema. / The financial crises are processes of losses arising from financial market mechanism. They affect the institutions of the financial system by the process of contagion. Sometimes it is equal to the domino effect. This process can make many healthy financial institutions become insolvents. It happens because economic agents are interconnected through contractual relations and become dependent on each other. Systemic risk can be understood as the risk of a huge loss in a system. The present work aims to study the properties of a contagion model proposed to study the effects of the spread of financial crises, as well as the measurement of systemic risk in the interbank system. This problem was investigated considering three different network topologies: Erdös-Rényi, Scale-Free and Empirical Interbank. The choice of these topologies was made by the fact that two of them - Scale-Free and Empirical Interbank - may emulate the real banking system and Erdös-Rényi has been used in several models in the literature. Each node is a bank and consists on a balance sheet split as liabilities (equity, borrowings and deposits) and assets (lendings, bonds and securities). It was analyzed the influence of the coefficient of leverage, the influence of the initial probability of default and the influence of the number of clusters on the Empirical Interbank. The systemic risk was measured using the Systemic Risk Indicator, Systemic Index and Systemic Value at Risk. It was shown that Scale-Free networks are more robust against random attacks, avoiding increases in the number of defaults. The abrupt increase in the impact caused by the crisis happens due to the increase in coefficient of leverage. The number of clusters on Empirical Interbank network impacts the robustness of the system. The model reproduces the result known as Too Interconnected to Fail, that is, banks more interconnected offer higher risk to the system.