China's insurance companies' efficiency: an empirical study

Great achievements have been seen in China's insurance industry in the past 20 years, however, inefficiency problems were prevailing as many insurance company only pursuing the expansion of the quantity, but not the increase of their key competitiveness. How to improve the core competitiveness of China's insurance industry, especially the efficiency of Chinese-funded insurance companies, has always been an important issue that the Chinese government, regulators and insurance institutions have been paying attention to and exploring for a long time. This thesis uses the most advanced efficiency evaluation model - three-stage DEA method and a samples of 43 property insurance companies and 53 life insurance companies to calculate the technical efficiency, pure technical efficiency and scale efficiency from 2008 to 2011. The research results show that China’s insurance industry has high technical efficiency and pure technical efficiency, while its scale efficiency is low and its scale is still in an expanding stage from 2008 to 2011. In order to compete with foreign insurance companies, Chinese insurance companies must upgrade their key competitiveness and pure technical efficiency as soon as possible. Through more rational allocation of resources and more refined management, China's insurance industry can achieve its development goals. According to Empirical research, the main reason for the weak core competitiveness of Chinese small and medium-sized insurance companies is the imbalance of inputs and outputs. Therefore, through rational allocation of resources, optimization of business strategies, and control of costs, the efficiency of companies can be improved. By studying the factors affecting the efficiency of Chinese insurance companies, the conclusion shows that the expansion of asset size will significantly increase the technical efficiency and scale efficiency of life insurance companies and property insurance companies. Moreover, all efficiency of foreign property insurance companies outperform Chinese-funded ones, while technical efficiency of Chinese-funded life insurance companies outperform foreign ones.Tem-se assistido nos últimos 20 anos um desenvolvimento extraordinário da indústria de seguros na China, contudo, o problema da ineficiência continua a ser um problema grave porquanto que a indústria de seguros na China caracteriza-se no essencial pela expansão em dimensão e não nos fatores de competitividade. A necessidade de melhoria da capacidade competitiva da indústria chinesa de seguros e, em especial, a eficiência de seguradoras de capital chinês tem sido uma preocupação importante para o governo chinês, para os reguladores e para as próprias instituições seguradoras. Este trabalho, utilizando o método de eficiência DEA de três estádios e uma amostra composta por 43 seguradoras de seguros imobiliários e 53 outras do ramo vida, computou a eficiência técnica, eficiência técnica pura e a escala de eficiência no período de 2008 e 2011. Os resultados da investigação mostram que a indústria seguradora da China tem uma elevada eficiência técnica e técnica pura, enquanto que a escala de eficiência é baixa e demonstramos que se encontrava numa fase de desenvolvimento no período de 2008 e 2011. De acordo com a nossa investigação empírica, a razão principal da fraca competitividade das seguradoras chinesas de pequena e média dimensão é o desequilíbrio entre «inputs» e «outputs». Com uma afetação racional de recursos, otimização de estratégias de mercados e controlo de custos, a eficiência das seguradoras poderia ser melhorada. Na análise de fatores que afetam a eficiência das empresas chinesas de seguros, o nosso estudo mostra que o reforço de ativos contribuirá para a melhoria da eficiência técnica e da escala de eficiência de seguradoras tanto do ramo vida como do ramo imobiliário. Concluímos ainda que as seguradoras estrangeiras têm melhor eficiência do que as congéneres chinesas, mas avaliando pela ótica de eficiência técnica, as seguradoras chinesas têm melhor desempenho que as seguradoras estrangeiras

An Integrated Approach for Reliability Evaluation of Electric Power Systems Considering Natural Gas Network Reliability

With the rapid increase of demand for electric power and the growing complexity of the electric system, the reliable operation of electric systems is facing new challenges. Meanwhile, natural gas has been widely used in transportation, electricity generation, and heating. In addition, gas-fired turbines play a growing vital role in the generation of electricity. However, all the facilities in a natural gas network are subject to failures. The operation of gas-fired turbines will be affected by the status of natural gas network, and the insufficient supply of natural gas may cause the output of gas turbine units to reduce to zero. This power decrease may further influence the operation of power systems. Therefore, it is quite urgent to quantify the influence of natural gas networks on the power system reliability. A deep understanding of the operation of natural gas network is needed to quantify the impact that natural gas networks will bring to the power system reliability. The main facilities in a natural gas network are natural gas pipelines, compressor stations and natural gas sources. Additionally, the mathematical failure models have been developed for these facilities to build a reliability analysis framework for the gas network. The mass flow of natural gas at different failure conditions is analyzed by the maximum flow algorithm. Case studies are conducted on a modified Europe Belgium natural gas network to analyze the influences of different failures on the maximum flow of natural gas. The main problem discussed in this thesis is related to how the natural gas network operation status influences the reliability of power system. The coupling unit is the gas-fired turbine between and electric and gas infrastructures, while the simplified gas-fired turbine model used in this work shows a linear relation among the power generation and the mass flow of natural gas. In this thesis, reliability evaluation is performed based on the hierarchical level II which contains the generation system and the transmission system. The optimal power flow analysis has been conducted for the reliability evaluation. Based on the results of power flow, the status of load shedding can be obtained in a power system. Then, system reliability states can be determined. Failure statuses of both the natural gas network and electric system are simulated by Monte Carlo Simulation. Case studies are conducted on the RTS-79 system and the modified Europe Belgium natural gas network by using MATLAB and IBM CPLEX. The results indicate that the reliability of system decreases

Research on economic planning and operation of electric vehicle charging stations

Appropriately planning and scheduling strategies can improve the enthusiasm of Electric vehicles (EVs), reduce charging losses, and support the power grid system. Thus, this dissertation studies the planning and operating of the EV charging station. First, an EV charging station planning strategy considering the overall social cost is proposed. Then, to reduce the charging cost and guarantee the charging demand, an optimal charging scheduling method is proposed. Additionally, by considering the uncertainty of charging demand, a data-driven intelligent EV charging scheduling algorithm is proposed. Finally, a collaborative optimal routing and scheduling method is proposed

Vapor deposited perovskites solar cells

Owing to the advantages such as low cost and high efficiency, Perovskites solar cells have attracted widespread attention in the past few years. In this report, thermal co-evaporation method is employed for perovskites solar cell fabrication. We focus on light I-V characterization under different co-evaporation ratios in order to figure out the best conditions based on our experiment setup

Local and remote wind stress forcing of the seasonal variability of the Atlantic Meridional Overturning Circulation (AMOC) transport at 26.5°N

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 2488–2503, doi:10.1002/2014JC010317.The transport of the Atlantic Meridional Overturning Circulation (AMOC) varies considerably on the seasonal time scale at 26.5°N, according to observations made at the RAPID-MOCHA array. Previous studies indicate that the local wind stress at 26.5°N, especially a large wind stress curl at the African coast, is the leading contributor to this seasonal variability. The purpose of the present study is to examine whether nonlocal wind stress forcing, i.e., remote forcing from latitudes away from 26.5°N, affects the seasonal AMOC variability at the RAPID-MOCHA array. Our tool is a two-layer and wind-driven model with a realistic topography and an observation-derived wind stress. The seasonal cycle of the modeled AMOC transport agrees well with RAPID-MOCHA observations while the amplitude is in the lower end of the observational range. In contrast to previous studies, the seasonal AMOC variability at 26.5°N is not primarily forced by the wind stress curl at the eastern boundary, but is a result of a basin-wide adjustment of ocean circulation to seasonal changes in wind stress. Both the amplitude and phase of the seasonal cycle at 26.5°N are strongly influenced by wind stress forcing from other latitudes, especially from the subpolar North Atlantic. The seasonal variability of the AMOC transport at 26.5°N is due to the seasonal redistribution of the water mass volume and is driven by both local and remote wind stress. Barotropic processes make significant contributions to the seasonal AMOC variability through topography-gyre interactions.This study has been supported by the National Science Foundation (OCE 0927017).2015-10-0

A review on trend factor: examination of the trend factor’s performance with skipping period

Han, Zhou and Zhu (2016) proposed a trend factor to capture all the short-, mid- and long-term information which represents the well-known short-term reversal factor, the momentum factor and the long-term reversal factor. HZZ documented the superiority performance of the trend factor with its high and consistent abnormal return. Based on HZZ’s approach, this study provides some further examinations on the trend factor’s performance with the skipping period. The skipping period is widely used by related studies in order to mitigate bid-ask spread bias and avoid the opposite effects from shorter-term factors. The skipping period also provides a practical setup which considers the real-life trades execution issues. The study finds that with the skipping period, the performance of the trend factor largely declines and its superiority over other factors disappears. The trend factor’s monthly average return drops from 1.69% by more than 0.50% when the 1-day skipping periods are applied, and after applying the 5-day and 20-day skipping periods the return becomes lower than that of the short-term reversal factor and the momentum factor. The study also shows such impacts of skipping period over the trend factor is mainly due to the short-term reversal factor, and especially the 5-day lag of the trend factor, which accounts for 0.82% out of 1.69% of the trend factor’s return

Seasonal and interannual variability of downwelling in the Beaufort Sea

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C00A14, doi:10.1029/2008JC005084.In this paper, we examine the seasonal and interannual to decadal variability of oceanic downwelling in the Beaufort Sea. The surface wind stress is the primary driver for variability in the upper Arctic Ocean and sea ice. The seasonal variability of the surface wind over the western Arctic is strongly influenced by a high sea level pressure center that emerges in the fall and diminishes in the summer. The wind stress and sea ice velocity are both anticyclonic from fall to spring and thus force an upwelling along the Alaskan and Canadian coast and downwelling in the interior Beaufort Sea. The upwelling and downwelling varied significantly on the interannual to decadal time scales from 1979 to 2006. There was no significant correlation between the upwelling/downwelling rate in the Beaufort Sea and the Arctic Oscillation index over this 28 year period. The coastal upwelling and interior downwelling in the Beaufort Sea had gradually intensified from 1979 to 2006. This change was almost entirely due to the increase in sea ice velocity according to three additional sensitivity calculations. The anticyclonic ice velocity over the western Arctic Ocean accelerated in the 28 year period, and the acceleration was not driven solely by the wind stress. The geostrophic wind condition was actually similar between 1979–1986 and 1997–2004. However, the ice velocity was much greater in the latter period. We hypothesize that the change in ice dynamics (thinner and less areal coverage) was responsible for the change of ice velocity.his study has been supported by the National Science Foundation’s Office of Polar Program (OPP0424074 and ARC-0902090), WHOI Arctic Initiative, and NASA’s Cryospheric Science Program (NNG05GN93G)