Multiple Transitions to Chaos in a Damped Parametrically Forced Pendulum

We study bifurcations associated with stability of the lowest stationary point (SP) of a damped parametrically forced pendulum by varying $\omega_0$ (the natural frequency of the pendulum) and $A$ (the amplitude of the external driving force). As $A$ is increased, the SP will restabilize after its instability, destabilize again, and so {\it ad infinitum} for any given $\omega_0$. Its destabilizations (restabilizations) occur via alternating supercritical (subcritical) period-doubling bifurcations (PDB's) and pitchfork bifurcations, except the first destabilization at which a supercritical or subcritical bifurcation takes place depending on the value of $\omega_0$. For each case of the supercritical destabilizations, an infinite sequence of PDB's follows and leads to chaos. Consequently, an infinite series of period-doubling transitions to chaos appears with increasing $A$. The critical behaviors at the transition points are also discussed.Comment: 20 pages + 7 figures (available upon request), RevTex 3.

Discovery and Genetic Characterization of Novel Paramyxoviruses Related to the Genus Henipavirus in Crocidura Species in the Republic of Korea

Paramyxoviruses, negative-sense single-stranded RNA viruses, pose a critical threat to human public health. Currently, 78 species, 17 genera, and 4 subfamilies of paramyxoviruses are harbored by multiple natural reservoirs, including rodents, bats, birds, reptiles, and fish. Henipaviruses are critical zoonotic pathogens that cause severe acute respiratory distress and neurological diseases in humans. Using reverse transcription-polymerase chain reaction, 115 Crocidura species individuals were examined for the prevalence of paramyxovirus infections. Paramyxovirus RNA was observed in 26 (22.6%) shrews collected at five trapping sites, Republic of Korea. Herein, we report two genetically distinct novel paramyxoviruses (genus: Henipavirus): Gamak virus (GAKV) and Daeryong virus (DARV) isolated from C. lasiura and C. shantungensis, respectively. Two GAKVs and one DARV were nearly completely sequenced using next-generation sequencing. GAKV and DARV contain six genes (30 -N-P-M-F-G-L-50 ) with genome sizes of 18,460 nucleotides and 19,471 nucleotides, respectively. The phylogenetic inference demonstrated that GAKV and DARV form independent genetic lineages of Henipavirus in Crocidura species. GAKV-infected human lung epithelial cells elicited the induction of type I/III interferons, interferon-stimulated genes, and proinflammatory cytokines. In conclusion, this study contributes further understandings of the molecular prevalence, genetic characteristics and diversity, and zoonotic potential of novel paramyxoviruses in shrews

Developing a CALS/EC engine of the ELECTROPIA in Korea

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The role of fintech in mitigating information friction in supply chain finance

Micro, small, and medium-sized enterprises in developing countries face severe financing difficulties, especially when trying to expand internationally. "Information friction" is a significant cause of this financing gap. Recent financial technologies (fintech) can improve supply chain finance efficiency. This paper therefore proposes a conceptual and analytical framework to study how fintech can close the financing gap by reducing information friction. We classify fintech into two categories: information processing technology (Type-A) and information collecting technology (Type-B) and find that both help close the financing gap by lowering the probability of misclassification of good firms as bad. Banks' optimal Type-A investment increases in the bank's size, profit margin, and the fraction of good firms in the market. They invest in Type-B if and only if the investment is sufficiently small. Due to "double marginalization," a bank's optimal fintech investment is lower than a socially optimal level, calling for mechanisms to incentivize or complement banks' investment in fintech

Impacts of social distancing policy and vaccination during the COVID-19 pandemic in the Republic of Korea

This paper investigates the dynamic impact of social distancing policy on coronavirus disease (COVID-19) infection control, mobility of people, and consumption expenditures in the Republic of Korea. We employ structural and threshold vector autoregressive (VAR) models using big-data-driven mobility data, credit card expenditure, and a social distancing index. We find that the social distancing policy significantly reduces the spread of COVID-19, but there exists a significant, growing trade-off between infection control and economic activity over time. When the level of stringency in social distancing is already high, its marginal effect on mobility is estimated to be smaller than when social distancing stringency is low. Increased vaccination is found to significantly reduce the critical rate while it increases visitors and consumption expenditures. The results also show that the effect of social distancing policy on mobility reduction is strongest among the population of age under 20 and the weakest among the population of age over 60

Credit chain and sectoral comovement: A multi-region investigation

This paper empirically examines how sectoral comovements are correlated with trade credit usage in a multi-region setting. Extending the models in Shea (2002) and Raddatz (2010), we develop a framework that captures the impact of trade credit usage on comovement between sectors within an economy and across economies separately. Using the Multi-Regional Input-Output Table developed by the Asian Development Bank, we assemble a dataset consisting of 14 manufacturing industries for 53 economies. We provide empirical evidence that trade credit linkage is an influential channel for both the domestic and cross-border shocks to propagate and create a more profound impact on industries around the globe. We find that the impact of domestic credit chains on sectoral comovement is twice as strong as that of the international ones. We further examine the time trend of this relationship and find that, from 2000 to 2018, the positive relationship between the intensity of trade credit usage and sectoral correlation decreases. We posit that this could be due to more diversified global trade pattern changes during these two decades

UWB 채널 상에서 실내 위치인식을 위한 시뮬레이터

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