Seismic structure of the mantle beneath the southwestern Pacific

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2001.Includes bibliographical references (leaves 24-28).We jointly invert 1396 frequency-dependent travel times of turning and surface waves such as S, sS, SS, sSS, SSS, Sa, R1, and G1, together with 82 travel times of multiple ScS waves, to obtain a high-resolution, two-dimensional (2-D) vertical tomogram for the corridor between the Ryukyu subduction zone and Hawaii, which traverses the Hawaiian Swell between Midway and Oahu. The data analysis, inversion procedure, and parameterization are similar to our previous study along the Tonga-Hawaii corridor [Katzman et al., 1998], but in this study we add corrections to the measurements that account for the crustal heterogeneity and topography along the path. The model parameters include shear-speed variations throughout the mantle, perturbations to shearwave radial anisotropy in the uppermost mantle, and the topographies of the 410- and 660-km discontinuities. The model we obtained, which is well resolved in the upper mantle, exhibits high shear speeds at shallow depths and low speeds in the transition zone beneath the Pacific part of the corridor, with the lowest shear speed within a distinct upper-mantle anomaly at the depth of 200-400km near the Hawaiian Swell. Furthermore, we inverted the data from individual source arrays in New Hebrides, Solomon, and Mariana Island for two-dimensional vertical tomograms of mantle structure using the same technique as the Ryukyu-Hawaii corridor. The 2-D tomograms for these corridors were generally consistent with previous tomographic results, although they show uppermantle features that are smaller in scale and larger amplitude than published global models. We then inverted the entire data set from all corridors for a 3-D model of the southwestern Pacific upper mantle. At low wavenumbers, this regional model is consistent with large-scale features found from global tomography. However, our model displays greater lateral heterogeneity in both isotropic and anisotropic structure than the global models, especially in the 200-400 km depth range, which can be attributed to the better resolution of small-scale features by our data set. Fast and slow anomalies in isotropic shear speed are observed in the upper mantle, suggesting a complex 3-D mantle flow in the southwestern Pacific upper mantle.by Liangjun Chen.S.M

Testing Homogeneity in Panel Data Models with Interactive Fixed Effects

This paper proposes a residual-based Lagrange Multiplier (LM) test for slope homogeneity in large-dimensional panel data models with interactive fixed effects. We first run the panel regression under the null to obtain the restricted residuals and then use them to construct our LM test statistic. We show that after being appropriately centered and scaled, our test statistic is asymptotically normally distributed under the null and a sequence of Pitman local alternatives. The asymptotic distributional theories are established under fairly general conditions that allow for both lagged dependent variables and conditional heteroskedasticity of unknown form by relying on the concept of conditional strong mixing. To improve the finite-sample performance of the test, we also propose a bootstrap procedure to obtain the bootstrap p-values and justify its validity. Monte Carlo simulations suggest that the test has correct size and satisfactory power. We apply our test to study the Organization for Economic Cooperation and Development economic growth model.</jats:p

The Development of NBA in China: A Glocalization Perspective

The growing sport industry and 1.3 billion potential consumers in China have been garnering tremendous attention from more and more overseas professional sport leagues. Comparatively, the National Basketball Association (NBA) has had remarkable success in the Chinese market. From the perspective of sport competition or marketing operations, the NBA’s achievement in China provides a model for other overseas sport leagues. This case study was organized by summarizing the developmental history of NBA in China, analyzing its current promotional practices, investigating into its marketing strategies, and extrapolating practical references for other sport leagues aiming to penetrating into the Chinese marketplace. In the perspective of glocalization, multinational corporations should combine both standardized and adapted elements to conceptualize globally and act locally (Tanahashi, 2008). By taking this approach, marketers can meet the needs of local consumers effectively while still maintaining some extent of global standardization (Singh, Kumar, & Baack, 2005). To obtain in-depth understanding about NBA globalization and localization in China, we conducted one-on-one interviews with Chinese academic scholars in sport management and practitioners in Chinese basketball industry and NBA China. Two focus groups with six participants in each group were conducted to learn the perception of NBA products from the perspective of Chinese consumer. The qualitative data analysis was organized around four major aspects: products, media, management and public relations, which were highlighted in the glocalization of transnational corporations (Yang, 2003; Zhang, 2007) The current case study concluded that although NBA has achieved huge successes in the areas of building a large fan base, increasing media exposure, and garnering net income after its entry to China, it still faces many challenges. One viable solution for the NBA is to bring authentic American cultural commodities while adding Chinese characteristics to accommodate local fans. Combining global heroes such as Michael Jordan and Kobe Bryant and local hero such as Yao Ming, Yi Jianlian, and Jeremy Lin, NBA games will continue to appeal to millions of Chinese fans. Meantime, NBA management needs to continue seeking ways to work out and through the differences in government models and cultural contexts between China and United States. Some viable actions include the promotion of Chinese youth basketball, the training service for elite basketball players, and government-level public relations. In addition, this study suggested that the research framework of glocalization would be an ever intriguing inquiry needed for other sport organizations or leagues seeking expansion to overseas markets

Dolfin: Diffusion Layout Transformers without Autoencoder

In this paper, we introduce a novel generative model, Diffusion Layout Transformers without Autoencoder (Dolfin), which significantly improves the modeling capability with reduced complexity compared to existing methods. Dolfin employs a Transformer-based diffusion process to model layout generation. In addition to an efficient bi-directional (non-causal joint) sequence representation, we further propose an autoregressive diffusion model (Dolfin-AR) that is especially adept at capturing rich semantic correlations for the neighboring objects, such as alignment, size, and overlap. When evaluated against standard generative layout benchmarks, Dolfin notably improves performance across various metrics (fid, alignment, overlap, MaxIoU and DocSim scores), enhancing transparency and interoperability in the process. Moreover, Dolfin's applications extend beyond layout generation, making it suitable for modeling geometric structures, such as line segments. Our experiments present both qualitative and quantitative results to demonstrate the advantages of Dolfin

State of Charge Estimation for Lithium-Ion Battery by Using Dual Square Root Cubature Kalman Filter

The state of charge (SOC) plays an important role in battery management systems (BMS). However, SOC cannot be measured directly and an accurate state estimation is difficult to obtain due to the nonlinear battery characteristics. In this paper, a method of SOC estimation with parameter updating by using the dual square root cubature Kalman filter (DSRCKF) is proposed. The proposed method has been validated experimentally and the results are compared with dual extended Kalman filter (DEKF) and dual square root unscented Kalman filter (DSRUKF) methods. Experimental results have shown that the proposed method has the most balance performance among them in terms of the SOC estimation accuracy, execution time, and convergence rate

An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect

It is known that the blazar jet emissions are dominated by non-thermal radiation while the accretion disk jets are normally dominated by thermal emission. In this work, our aim is to study the connection between the two types of emission by investigating the correlation between the blazar emission line intensity property, which embodies the nature of accretion disk, and the $\gamma$-ray flux property, which is the representative of jet emission. We compiled a sample of 656 blazars with available emission line equivalent widths ($EW$), the GeV $\gamma$-ray flux, and the SED information from the literature. In this work, we found 55 previous BCUs are now identified as FSRQs, and found 52 Changing-look blazars based on their $EW$ and 45 of them are newly confirmed. These Changing-look blazars have a larger accretion ratio (${\dot M}/{\dot M}_{\rm Edd}$) than BL Lac objects. In addition, we suggest that the lower synchrotron peak blazars (LSPs) could be the source of Changing-look blazars because 90.7\% of the Changing-look blazars in this work are confirmed as LSPs. An anti-correlation between $EW$ and continuum intensity, the so-called global Baldwin effect (BEff) has been confirmed. We suggest the steeper global BEff observed for blazar than for radio-quiet active galactic nuclei (RQ-AGNs) is caused by the inverse Compton scattering of broad-emission-line photons. This interpretation is further supported by the positive correlation between the emission line $EW$ and intrinsic inverse Compton luminosity.Comment: Accepted to Ap