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Hitoshi Yamada

Publications and source records attributed to Hitoshi Yamada.

2 recordsLinked to original sources

Universal Basic Income with Time-Decaying Currency: Structural Effects on Essential Labor and Long-Term Formation

Time-decaying currencies have long been discussed in economic theory as a means to discourage hoarding and promote circulation. However, their modern digital implementation as a universal basic income (UBI) mechanism raises unresolved structural questions regarding labor participation and long-term social reproduction. In this study, we analyze a dual-currency model in which a time-decaying currency is distributed exclusively as UBI, while labor income and savings are denominated in a standard currency. Through agent-based simulations, we identify the acceptance ratio of the time-decaying currency for necessities as a critical design parameter. Our results show that essential labor does not necessarily collapse under such a system. Nevertheless, beyond a threshold acceptance ratio, delayed labor participation and weakened human capital formation emerge even in the absence of material deprivation. These findings suggest that time-decaying currency can stabilize short-term living conditions while distorting long-term formation incentives, depending on system design.

cs.CE

Bistability in the wake of a wavy cylinder

We investigate the wake dynamics of an optimally designed wavy cylinder that completely suppresses the Kármán vortex shedding. Such a wavy cylinder is forced to oscillate with a sinusoidal motion in the crossflow direction. Examination of the lift force spectrum reveals that a critical forcing frequency exists, below which the flow control effectiveness of the wavy cylinder is retained, and beyond which the inherent vortex shedding resurrects. Moreover, the resurrected unsteady vortex shedding can persist even without sustained forcing, leading to the loss of control efficacy. This suggests that in addition to the steady state developed from uniform initial condition, an oscillatory state exists in the wake of wavy cylinder if the initial state is sufficiently perturbed. The discovery of the bistable states calls for examination of the flow control effectiveness of the wavy cylinder in more complicated inflow conditions.

physics.flu-dyn