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An Interacting Agent Model of Economic Crisis [article]

Yuichi Ikeda
2020 arXiv   pre-print
Most national economies are linked by international trade. Consequently, economic globalization forms a massive and complex economic network with strong links, that is, interactions arising from increasing trade. Various interesting collective motions are expected to emerge from strong economic interactions in a global economy under trade liberalization. Among the various economic collective motions, economic crises are our most intriguing problem. In our previous studies, we have revealed that
more » ... the Kuramoto's coupled limit-cycle oscillator model and the Ising-like spin model on networks are invaluable tools for characterizing the economic crises. In this study, we develop a mathematical theory to describe an interacting agent model that derives the Kuramoto model and the Ising-like spin model by using appropriate approximations. Our interacting agent model suggests phase synchronization and spin ordering during economic crises. We confirm the emergence of the phase synchronization and spin ordering during economic crises by analyzing various economic time series data. We also develop a network reconstruction model based on entropy maximization that considers the sparsity of the network. Here network reconstruction means estimating a network's adjacency matrix from a node's local information. The interbank network is reconstructed using the developed model, and a comparison is made of the reconstructed network with the actual data. We successfully reproduce the interbank network and the known stylized facts. In addition, the exogenous shock acting on an industry community in a supply chain network and financial sector are estimated. Estimation of exogenous shocks acting on communities of in the real economy in the supply chain network provide evidence of the channels of distress propagating from the financial sector to the real economy through the supply chain network.
arXiv:2001.11843v1 fatcat:4hoi3aqq4zhd7l7p7it4fnt37m

Hypergraph Clustering Based on PageRank [article]

Yuuki Takai, Atsushi Miyauchi, Masahiro Ikeda, Yuichi Yoshida
2020 arXiv   pre-print
The second algorithm was developed by Ikeda et al. [16] .  ... 
arXiv:2006.08302v1 fatcat:rexru2qywfhq7kjzz7ft5bvshe

Vehicular slip ratio control using nonlinear control theory

Yuichi Ikeda, Takashi Nakajima, Yuichi Chida
2011 IFAC Proceedings Volumes  
In this paper, we discuss integrated vehicle slip ratio control under both deceleration and acceleration without the need for controller switching, and also propose a design method for such an integrated slip ratio controller. When a vehicle switches from acceleration to deceleration and vice versa, the slip ratio varies discontinuously. Here, the slip ratio is approximated to a continuous function by using a sigmoid function. And a controller is then designed by using feedback linearization
more » ... ed on the approximated slip ratio. The stability of the designed control system is proven by Lyapunov stability theorem. Furthermore, we propose a robust control method based on a disturbance observer and sliding mode control theory. Finally, the effectiveness of the proposed control method is verified through numerical simulation.
doi:10.3182/20110828-6-it-1002.01325 fatcat:pfjkun6smfeqjeo5utwnhgtpmu

Agent Simulation of Chain Bankruptcy [article]

Yuichi Ikeda, Yoshi Fujiwara, Wataru Souma, Hideaki Aoyama, Hiroshi Iyetomi
2007 arXiv   pre-print
We have conducted an agent-based simulation of chain bankruptcy. The propagation of credit risk on a network, i.e., chain bankruptcy, is the key to nderstanding largesized bankruptcies. In our model, decrease of revenue by the loss of accounts payable is modeled by an interaction term, and bankruptcy is defined as a capital deficit. Model parameters were estimated using financial data for 1,077 listed Japanese firms. Simulations of chain bankruptcy on the real transaction network consisting of
more » ... hose 1,077 firms were made with the estimated model parameters. Given an initial bankrupt firm, a list of chain bankrupt firms was obtained. This model can be used to detect high-risk links in a transaction network, for the management of chain bankruptcy.
arXiv:0709.4355v1 fatcat:yurxwqz3enaipn73nkkgilbdv4

Network Analysis of Attitudes towards Immigrants in Asia [article]

Rachael Kei Kawasaki, Yuichi Ikeda
2020 arXiv   pre-print
This study models cross-national attitudes towards immigrants in East and Southeast Asia as a signed and weighted bipartite network of countries and evaluative reactions to a variety of political issues, or determinants. This network is then projected into two one-mode networks, one of countries and one of determinants, and community detection methods are applied. The paper aims to fill two deficiencies in the current research on attitudes towards immigrants: 1) the lack of cross-national
more » ... s in Asia, a region where migration is growing, and 2) the tendency of researchers to treat determinants as uncorrelated, despite the interdependent nature of evaluative reactions. The results show that the nine countries in the sample are a cohesive clique, showing greater similarities than differences in the determinants of their attitudes. A blockmodeling approach was employed to identify eight determinants in attitudes towards immigrants, namely views on independence and social dependencies, group identities, absolute or relative moral orientation, attitudes towards democracy, science and technology, prejudice and stigma, and two determinants related to religion. However, the findings of this survey yielded some surprising results when compared with the literature review. First, education was not found to be a significant determinants of attitudes towards immigrants, despite its strong and consistent predictive power in European models. Second, prejudice appears to be mediated in part by religion, especially in religious identification and belief in God. Group identity and prejudice also appear to be related, though only weakly. Finally, anxiety appears in clusters related to social norms, suggesting that fears regarding immigrants relates closely to expectations of others' behavior.
arXiv:2004.04367v1 fatcat:dojlpgzdczakhiwisufvpcx3em

Vehicular Slip Ratio Control Using Nonlinear Control Theory

Yuichi IKEDA, Takashi NAKAJIMA, Yuichi CHIDA
2012 Journal of System Design and Dynamics  
In this paper, we discuss integrated vehicle slip ratio control under both deceleration and acceleration without the need for controller switching, and also propose a design method for such an integrated slip ratio controller based on the slip ratio dynamics. When a vehicle switches from acceleration to deceleration and vice versa, the slip ratio varies discontinuously. Here, the slip ratio is approximated to a continuous function by using a sigmoid function. And a controller is then designed
more » ... using feedback linearization based on the approximated slip ratio. The stability of the designed control system is proven by Lyapunov stability theorem. Furthermore, we propose a robust control method based on a disturbance observer and sliding mode control theory. Finally, the effectiveness of the proposed control method is verified through numerical simulation.
doi:10.1299/jsdd.6.145 fatcat:db7skng4grcopkxf32a5raomxq

Regional medical inter-institutional cooperation in medical provider network constructed using patient claims data from Japan [article]

Yu Ohki, Yuichi Ikeda, Susumu Kunisawa, Yuichi Imanaka
2022 arXiv   pre-print
The aging world population requires a sustainable and high-quality healthcare system. To examine the efficiency of medical cooperation, medical provider and physician networks were constructed using patient claims data. Previous studies have shown that these networks contain information on medical cooperation. However, the usage patterns of multiple medical providers in a series of medical services have not been considered. In addition, these studies used only general network features to
more » ... nt medical cooperation, but their expressive ability was low. To overcome these limitations, we analyzed the medical provider network to examine its overall contribution to the quality of healthcare provided by cooperation between medical providers in a series of medical services. This study focused on: i) the method of feature extraction from the network, ii) incorporation of the usage pattern of medical providers, and iii) expressive ability of the statistical model. Femoral neck fractures were selected as the target disease. To build the medical provider networks, we analyzed the patient claims data from a single prefecture in Japan between January 1, 2014 and December 31, 2019. We considered four types of models: a model using node strength and linear regression to a model using feature representation by node2vec and regression tree ensemble, which is a machine learning method. The results showed that a stronger medical provider reduces the duration of hospital stay. The overall contribution of the medical cooperation to the duration of hospital stay extracted from the medical provider network using node2vec is approximately 20%, which is approximately 20 times higher than the model using strength.
arXiv:2203.11440v1 fatcat:y6sqo4icerfhxpejhpqi2zlunq

Trade Network Reconstruction and Simulation with Changes in Trade Policy [article]

Yuichi Ikeda, Hiroshi Iyetomi
2018 arXiv   pre-print
The interdependent nature of the global economy has become stronger with increases in international trade and investment. We propose a new model to reconstruct the international trade network and associated cost network by maximizing entropy based on local information about inward and outward trade. We show that the trade network can be successfully reconstructed using the proposed model. In addition to this reconstruction, we simulated structural changes in the international trade network
more » ... d by changing trade tariffs in the context of the government's trade policy. The simulation for the FOOD category shows that import of FOOD from the U.S. to Japan increase drastically by halving the import cost. Meanwhile, the simulation for the MACHINERY category shows that exports from Japan to the U.S. decrease drastically by doubling the export cost, while exports to the EU increased.
arXiv:1806.00605v1 fatcat:kcwyjdvwmzfwrbfesxsdmlai54

Power Grid with 100 -- Nexus of Energy, Environment, and Economic Growth [article]

Yuichi Ikeda
2019 arXiv   pre-print
We estimated system-wise levelized cost of electricity (LCOE) for a power grid with a high level of renewable energy using our grid optimization model. The estimation results of the system-wise LCOE are discussed in terms of the nexus of energy, environment, and economic growth for Small Island Developing States (SIDS) economies. While 100 possible with the usage of electricity storage, the estimated LCOE is as high as 397 /MWh which is substantially higher than electricity prices for
more » ... l consumers in the US and Japan. The susceptibility analyses imply that the estimated LCOE increase of 223 corresponds to an as high as 11 economic growth would have a significant negative impact on SIDS economies. However, hydrogen production via the electrolysis of water using the excess energy supply from solar photovoltaics would reduce the LCOE, therefore higher economic growth would be attained with less CO2 emission.
arXiv:1904.04597v1 fatcat:fod65cehgbfjlfpvgygyd26rhe

Direct Evidence for Synchronization in Japanese Business Cycle [article]

Yuichi Ikeda, Hideaki Aoyama, Hiroshi Iyetomi, Hiroshi Yoshikawa
2013 arXiv   pre-print
We have analyzed the Indices of Industrial Production (Seasonal Adjustment Index) for a long period of 240 months (January 1988 to December 2007) to develop a deeper understanding of the economic shocks. The angular frequencies estimated using the Hilbert transformation, are almost identical for the 16 industrial sectors. Moreover, the partial phase locking was observed for the 16 sectors. These are the direct evidence of the synchronization in the Japanese business cycle. We also showed that
more » ... e information of the economic shock is carried by the phase time-series. The common shock and individual shocks are separated using phase time-series. The former dominates the economic shock in all of 1992, 1998 and 2001. The obtained results suggest that the business cycle may be described as a dynamics of the coupled limit-cycle oscillators exposed to the common shocks and random individual shocks.
arXiv:1305.2263v1 fatcat:n6xvij26tbbttbfyemcksjvyk4

Bow-tie structure and community identification of global supply chain network [article]

Abhijit Chakraborty, Yuichi Ikeda
2020 arXiv   pre-print
Ikeda developed a agent-based model and ran realistic simulation of the chain bankruptcy caused by a failure of a single firm [4] . K. J. Mizgier et. al.  ... 
arXiv:2003.02343v1 fatcat:ooug2y5owbgvfhtgotowjsuqym

UBE1a Suppresses Herpes Simplex Virus-1 Replication

Marina Ikeda, Akihiro Ito, Yuichi Sekine, Masahiro Fujimuro
2020 Viruses  
Herpes simplex virus-1 (HSV-1) is the causative agent of cold sores, keratitis, meningitis, and encephalitis. HSV-1-encoded ICP5, the major capsid protein, is essential for capsid assembly during viral replication. Ubiquitination is a post-translational modification that plays a critical role in the regulation of cellular events such as proteasomal degradation, protein trafficking, and the antiviral response and viral events such as the establishment of infection and viral replication.
more » ... ting enzyme (E1, also named UBE1) is involved in the first step in the ubiquitination. However, it is still unknown whether UBE1 contributes to viral infection or the cellular antiviral response. Here, we found that UBE1a suppressed HSV-1 replication and contributed to the antiviral response. The UBE1a inhibitor PYR-41 increased HSV-1 production. Immunofluorescence analysis revealed that UBE1a highly expressing cells presented low ICP5 expression, and vice versa. UBE1a inhibition by PYR-41 and shRNA increased ICP5 expression in HSV-1-infected cells. UBE1a reduced and retarded ICP5 protein expression, without affecting transcription of ICP5 mRNA or degradation of ICP5 protein. Additionally, UBE1a interacted with ICP27, and both partially co-localized at the Hsc70 foci/virus-induced chaperone-enriched (VICE) domains. PYR-41 reduced the co-localization of UBE1a and ICP27. Thus, our findings provide insights into the mechanism of UBE1a in the cellular response to viral infection.
doi:10.3390/v12121391 pmid:33291814 fatcat:kpfi3xvvqzdjnhwopmwseudy2m

Identification of Conduit Countries and Community Structures in the Withholding Tax Networks [article]

Tembo Nakamoto, Yuichi Ikeda
2018 arXiv   pre-print
Due to economic globalization, each country's economic law, including tax laws and tax treaties, has been forced to work as a single network. However, each jurisdiction (country or region) has not made its economic law under the assumption that its law functions as an element of one network, so it has brought unexpected results. We thought that the results are exactly international tax avoidance. To contribute to the solution of international tax avoidance, we tried to investigate which part of
more » ... the network is vulnerable. Specifically, focusing on treaty shopping, which is one of international tax avoidance methods, we attempt to identified which jurisdiction are likely to be used for treaty shopping from tax liabilities and the relationship between jurisdictions which are likely to be used for treaty shopping and others. For that purpose, based on withholding tax rates imposed on dividends, interest, and royalties by jurisdictions, we produced weighted multiple directed graphs, computed the centralities and detected the communities. As a result, we clarified the jurisdictions that are likely to be used for treaty shopping and pointed out that there are community structures. The results of this study suggested that fewer jurisdictions need to introduce more regulations for prevention of treaty abuse worldwide.
arXiv:1806.00799v1 fatcat:gwdcflljkrdlzkmixxxkkj636a

Driving/Braking Force Distribution of Four Wheel Vehicle by Quadratic Programming with Constraints

Yuichi IKEDA, Ryo SUZUKI, Yuichi CHIDA
2012 Journal of System Design and Dynamics  
This paper proposes a yaw rate tracking control method that distributes the driving/ braking force exerted on vehicles at the time of negotiating sharp turns and driving at high speeds. The proposed method employs quadratic programming to distribute the driving/braking force in order to equalize the tire load factor on all wheels and consider the limits of the driving/braking force. The yaw rate tracking performance can be improved even while driving at high speeds and negotiating sharp turns
more » ... setting limits for the driving/braking force, differential moment, etc. The effectiveness of our proposed method is proven by a numerical simulation.
doi:10.1299/jsdd.6.417 fatcat:t5kcwhlw7zeylffwa6m53sxwlq

Control of a Pneumatic Isolation Table Including Non-linear Quantizer

Masakazu KOIKE, Yuichi CHIDA, Yuichi IKEDA
2013 Transactions of the Society of Instrument and Control Engineers  
Active control methods are used to suppress vibrations in a pneumatic isolation table. To suppress vibration for large displacements, it is necessary to switch the control input instantaneously to the maximum or minimum input values. Therefore, active control by quantized control input generated using the on-off valves is suitable. To obtain high performance, it is necessary to consider the quantized action by on-off valves and the input time-delay that arises from loss of pressure. An
more » ... factor is that the quantizer used in this system is a non-linear quantizer. Although conventional methods can be applied to the system including the non-linear quantizer, it is highly possible that a performance of disturbance attenuation deteriorates compared to when using a linear quantizer. Therefore, a control method that can be applied to the system including the non-linear quantizer and can give high performance is proposed in this study. Furthermore, the proposed method is applied to a pneumatic isolation table and its performance is verified through numerical simulations and experiments.
doi:10.9746/sicetr.49.488 fatcat:5bytatyh3ngsjluarvggikcsaa
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