The Impact of Education and R&D Investment on Regional Economic Growth

The purpose of this paper is to examine the impact of education and R&D investment on regional economic growth in South Korea. We develop a simultaneous model of production, human capital accumulation, migration, population and physical capital investment of two regions: the Seoul Metropolitan Area and the rest of Korea. We decompose the regional growth path into a quality path and a quantity path to identify how regional economies grow and run simulations to evaluate alternative policies in terms of effectiveness and adaptability. The impact of education and R&D investment on regional growth in the rest of Korea is only 22.3% of that in the Seoul Metropolitan Area due to lower elasticity values of young in-migrants with respect to the investment in the rest of Korea. An enhanced efficiency of regional human capital accumulation is effective and adaptable to alleviate regional economic disparity

Legendrian singular links and singular connected sums

We study Legendrian singular links up to contact isotopy. Using a special property of the singular points, we define the singular connected sum of Legendrian singular links. This concept is a generalization of the connected sum and can be interpreted as a tangle replacement, which provides a way to classify Legendrian singular links. Moreover, we investigate several phenomena only occur in the Legendrian setup

Hyperbolic Organizational Identity and Identity of Digital Artifacts: A Comparative Study of Healthcare Innovations

As digital technologies move toward the core of an organization’s offerings, the identity of many contemporary organizations is now born in association with the digital technology that characterizes them. Entrepreneurs largely rely on setting up high expectations to attract initial resources to materialize the idea for their digital innovation. However, such a tactic may be problematic when their eventual digital artifact contradicts their core organizational identity, leading to their legitimacy loss. In this ongoing study, we explore a novel phenomenon of hyperbolic organizational identity. Drawing on longitudinal archival sources, we conduct a comparative case study of IBM Watson and DeepMind, whose identities both became hyperbolic, yet experienced different outcomes in their healthcare innovations. From our findings to date, a preliminary dialectical process model is presented that depicts the interplay between organizational and technical identities of the digital artifact in leading to the formation and change in hyperbolic organizational identity

Development of Large-Scale Seawater Battery Cells for High Energy Density

School of Energy and Chemical Engineering (Energy Engineering (Battery Science and Technology))Lithium-ion batteries (LIBs) are the most widely used rechargeable energy storage systems. However, the future expanding of the LIB technology is limited due to the high cost and scarcity of both core elements of lithium and cobalt. The use of cheap earth-abundant metals such as sodium, aluminum, potassium, calcium, and magnesium in their corresponding metal-based batteries which working on the same principle as LIBs, would greatly reduce the cost of battery technology. Nevertheless, despite the economic advantage of production process, the large-scale production of these metal-based batteries have been limited by their lower gravimetric and volumetric energy densities. Rechargeable seawater batteries (SWBs) are regarded as sustainable alternatives to Li-ion batteries due to the use of an unlimited and free source of Na ion active materials. Although many approaches including the introduction of new catalysts have successfully improved the performance of SWBs, reconsidering the cell design is an urgent requirement to improve the performance and scale up the production of practical batteries. In this study, by adjusting the maximum space efficiency, a rectangular cell is developed which due to its unique architecture, benefits from optimized contact to improve the overall charge transfer in the system. In view of the rigidity of the solid electrolyte, the novel cell model is intended to have adequate flexibility to be easily transported and practically utilized. At the same time as the development of the cell platform, energy efficiency was also improved by improving the materials and assembly methods for each part of the seawater battery, which will be an indicator for future battery development. Furthermore, the enhanced efficiency of the parallel stacked modules, indicates the capability of this cell in practical use. The seawater battery module was actually operated in the ocean to prove its potential, and an automated pilot design for uniform cell production was also carried out. The designed catalyst-free cell system shows a record capacity of 3.8 Ah (47.5 Ah kg???1), energy of 11 Wh (137.5 Wh kg???1), and peak power of 523 mW for individual unit cell, while it also retains performance up to 100 cycles. This design paves the way for commercializing rechargeable seawater batteries.ope

Modeling of HVDC System to Improve Estimation of Transient DC Current and Voltages for AC Line-to-Ground FaultAn Actual Case Study in Korea

A new modeling method for high voltage direct current (HVDC) systems and associated controllers is presented for the power system simulator for engineering (PSS/E) simulation environment. The aim is to improve the estimation of the transient DC voltage and current in the event of an AC line-to-ground fault. The proposed method consists primary of three interconnected modules for (a) equation conversion; (b) control-mode selection; and (c) DC-line modeling. Simulation case studies were carried out using PSS/E and a power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC) model of the Jeju-Haenam HVDC system in Korea. The simulation results are compared with actual operational data and the PSCAD/EMTDC simulation results for an HVDC system during single-phase and three-phase line-to-ground faults, respectively. These comparisons show that the proposed PSS/E modeling method results in the improved estimation of the dynamic variation in the DC voltage and current in the event of an AC network fault, with significant gains in computational efficiency, making it suitable for real-time analysis of HVDC systems.111Ysciescopu