Indigenous languages face increasing pressure from national and global languages, yet many young speakers continue to use them for reasons not fully understood. This study investigates what motivates Balinese youth to sustain their language in a multilingual society and how these motivations inform language planning. Using a mixed-methods design, the study analyses survey data (N = 259) and open-ended responses (N = 73) to examine four motivational constructs: sense of identity, socio-cultural connectedness, sense of responsibility, and multilingualism goals. Structural equation modeling shows that socio-cultural connectedness and multilingualism goals significantly predict motivation intensity, whereas identity and responsibility, though positively valued, have weaker behavioral effects. These findings support a tripartite model of Indigenous language motivation: value-based (identity, responsibility), use-based (socio-cultural connectedness), and goal-oriented (multilingualism), that links individual motivation to ideological, status, and acquisition dimensions of language planning. The study argues that effective revitalization must move beyond symbolic pride toward everyday relational use and the integration of Indigenous languages into multilingual planning frameworks.
We investigate sparse and low-rank estimation methods for the intensity functions of multivariate Hawkes processes. While univariate Hawkes processes are approximated by integer-valued autoregressive models in the weak topology, we extend this approximation result to the multivariate setting. Building on this foundation, we develop new sparse and higher-order reduced-rank estimation procedures for multivariate Hawkes processes by leveraging methodology for multivariate integer-valued time series. In addition, we study a sparse weighted least squares estimator and establish error bounds for all proposed estimators. All theoretical results are derived by verifying novel moment and mixing conditions that ensure the applicability of concentration inequalities to weakly dependent data. Finally, we conduct an empirical study to assess the finite-sample performance of all estimation methods.
In the first year of the Meiji era (1868), Japan became a pioneer in emigration, sending its first emigrants to Hawaii, North America, and later to Latin America and the Caribbean. This emigration was supported by the Japanese government. After being defeated in World War II, Japan was reincorporated into the international community with the San Francisco Peace Treaty. After the war, when approximately six million people returned to a devastated Japan, postwar migration policy was oriented toward international cooperation, with the aim of having Japanese emigrants contribute to the development of the receiving countries. The Overseas Migration Council, created in 1955, was responsible for these policies and published its last report in 2000. In 2017, the Report of the Panel of Experts on Collaborating with Communities of Japanese Immigrants and Descendants (nikkei) in Latin America and the Caribbean presented a nikkei policy to the Ministry of Foreign Affairs of Japan. This paper will explore the historical background and current significance of the "Latin American Diplomatic Initiative" and the "Diplomacy of Human Dignity" of 2024, focusing on their relationship with Japanese emigration policy toward Latin America, especially migration for development.
This study proposes an observer-based vibration suppression framework for electric vehicle (EV) powertrains subject to nonlinear gear backlash. A control-oriented nonlinear two-inertia drivetrain model is constructed by incorporating shaft elasticity, viscous damping, backlash characteristics, sensor quantization, measurement noise, and communication delays to reflect practical vehicle conditions. Based on this model, a state observer is developed to estimate key torsional states, including relative displacement and backlash evolution, during rapid transitions between contact and non-contact modes. Using the estimated states, two vibration suppression control methods are designed: Angular Velocity Damping Control (AVDC) and an enhanced version with Impact Mitigation Control (AVDIMC). The proposed framework targets drivability-relevant low-frequency torsional oscillations (typically below 10-20 Hz) during torque reversals, rather than high-frequency gear mesh vibrations associated with Noise, Vibration, and Harshness (NVH) phenomena. Simulations using a high-fidelity exact backlash simulator demonstrate improved torque transmission and vibration suppression compared with conventional disturbance cancellation and motor-side angular velocity feedback control methods. Vehicle experiments further confirm the practical feasibility under real-time constraints, showing reductions in peak driveshaft torsional torque (approximately 2000 Nm to 1000 Nm) and vibration settling time (approximately 1.41 s to 0.53-0.57 s) during torque reversals. These reductions agree well with the simulation results.
