85 research outputs found
A comparative study of US and Korean employees
No full textPurpose - The purpose of this paper is to develop and empirically test a conceptual model based on the culturally endorsed implicit leadership theory to comprehend differences in the relationships between consideration, and initiating structure leadership styles and affective organizational commitment for US and Korean employees. Further, the authors investigate how rank and seniority moderate the relationships between the two leadership styles and affective organizational commitment in both countries. Design/methodology/approach - The authors developed and conducted a cross-sectional survey in the USA and Korea. To test the hypotheses that perform a series of hierarchical regression analyses. Findings - Survey results from 452 US and Korean employees show that the positive relationship between consideration leadership (i.e. people-oriented leadership) and affective organizational commitment was stronger among US employees than Korean employees. Initiating structure leadership (i.e. task-oriented leadership) was negatively related to affective organizational commitment in the USA, whereas this relationship was positive in South Korea (henceforth Korea). Further, these relationships were moderated by rank and seniority in Korea, but not in the USA. Specifically, the positive relationship between consideration leadership and affective organizational commitment was stronger when Korean employee's rank was higher and seniority was shorter. Originality/value - The comparative nature of the study enables to identify differences in the effects of leadership styles on affective organizational commitment across countries and thus helps to better understand employees from different cultures. Furthermore, the authors demonstrate the differential effects of demographic variables such as rank and seniority in the relationships of leadership styles and affective organizational commitment. The findings provide important managerial recommendations for how managers can better lead US and Korean employees
Optimal Power Management for Nanogrids Based on Technical Information of Electric Appliances
No full textA novel power management for nanogrids is presented. In this paper, effect of resident location in residence is taken into account for evaluation of power consumption in nanogrids. Depending on the resident location, operating conditions of heater, ventilation fan, and air-conditioner are adjusted. Electric appliances that allow delayed use, i.e., shiftable, are scheduled for efficient power management. Considering massive deployment of energy storage system (ESS) as a supplementary power source, effect of the ESS on power management is investigated. Demand response program for reduced electricity cost is also considered for power management. As a result, an objective consisting of power consumed by non-shiftable and shiftable electric appliances, power supplied/consumed by the ESS during discharging/charging, and time-varying electricity cost is formulated. Another objective for power management is a function of delays in scheduling of shiftable electric appliances. Variation of resident location combined with temporal use of electric appliances according to the resident location are considered as the resident behavior and incorporated into these two objectives. Using these two objectives, a multi-objective optimization is performed for nanogrids at each time interval. It is demonstrated by simulations that leveraging resident behavior is beneficial for power management of nanogrids. In addition, effects of the number of residents in each apartment and combined activity of each resident on the power management are presented with related simulation results. (C) 2019 Elsevier B.V. All rights reserved.
Does CSR Assurance Affect the Relationship between CSR Performance and Financial Performance?
No full textIn this study, we investigate the effect of assurance service of corporate social responsibility (CSR) reports on the relationship between CSR performance and firms’ financial performance. Specifically, we question whether firms having their CSR performance assured to benefit from such assurance services. Theory suggests that investors apply a lower discount rate when valuing firms if information from the firms is credible. Using a sample of 5040 large U.S. companies, we find that the CSR performance is positively associated with the firms’ financial performance on average and that there is a significant effect of CSR assurance service on the relationship between CSR performance and firms’ financial performance. This implies that firms having their CSR reports assured by external experts experience much higher financial performance than firms without such assurance service. Our findings are consistent with the prior studies and support our argument with regard to the CSR assurance service. The findings have implications for firms considering CSR assurance and accounting professionals for their opportunities
Granular activated carbon based microbial fuel cell for simultaneous decolorization of real dye wastewater and electricity generation
No full text
High-Efficiency Bi-Directional Single-Phase AC/DC Converter Design and Field Application for LVDC Distribution
No full textThis paper describes the design and field application of a high-efficiency single-phase AC/DC converter that is suitable for distribution lines. First, an appropriate AC/DC converter was designed in consideration of the environment of the application system. In order to ensure high efficiency and high reliability, we designed an optimum switching element and capacitor suitable for the converter, and the protection element of the AC/DC converter was designed based on these elements. The control function for the power converter suitable for an LVDC distribution system is proposed for highly reliable operation. The AC/DC converter was manufactured based on the design and its performance was verified during application in an actual low-voltage DC (LVDC) distribution grid through tests at the demonstration site. The application to a DC distribution system in an actual grid is very rare and it is expected that it will contribute to the expansion of LVDC distribution
Application of a DC Distribution System in Korea: A Case Study of the LVDC Project
No full textWith the rapid expansion of renewable energy and digital devices, there is a need for direct current (DC) distribution technology that can increase energy efficiency. As a result, DC distribution research is actively underway to cope with the sudden digitization and decentralization of load environment and power supply. To verify the possibility of DC distribution, Korea Electric Power Corporation (KEPCO) Research Institute made a DC distribution system connected with a real power system in Gwangju. The construction of the demonstration area mainly includes design of protection and grounding systems, operating procedures of insulation monitoring device (IMD), and construction of power converters. Furthermore, this paper goes beyond the simulation and the lab testing to apply DC distribution to a real system operation in advance. It is designed as a long-distance low-loaded customer for rural areas and operated by the DC distribution. In addition, safety and reliability are confirmed through field tests of DC distribution elements such as power conversion devices, protection and grounding systems. In particular, to improve the reliability of non-grounding system, the insulation monitoring device was installed and the algorithms of its operational procedures are proposed. Finally, this paper analyzes the problems caused by operating the actual DC distribution and suggests solutions accordingly
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