• Journal of Hydrogen and New Energy
• /
• v.34 no.2
• /
• pp.91-99
• /
• 2023

Participation in power trading using surplus power is considered a business model active in the domestic energy trade market, but it is limited only if the legal requirements according to the type, capacity, and use of the facilities to be applied for are satisfied. The hydrogen residential demonstration model presented in this paper includes solar power, energy storage system (ESS), fuel cell, and water electrolysis facilities in electrical facilities for private use with low-voltage power receiving system. The concept of operations strategy for this model focuses on securing the energy self-sufficiency ratio of the entire system, securing economic feasibility through the optimal operation module installed in the energy management system (EMS), and securing the stability of the internal power balancing issue during the stand-alone mode. An electric facility configuration method of a hydrogen residential complex demonstrated to achieve this operational goal has a structure in which individual energy sources are electrically connected to the main bus, and ESS is also directly connected to the main bus instead of a renewable connection type to perform charging/discharging operation for energy balancing management in the complex. If surplus power exists after scheduling, participation in power trading through reverse transmission parallel operation can be considered to solve the energy balancing problem and ensure profitability. Consequentially, this paper reviews the legal regulations on participation in electric power trading using surplus power from hydrogen residential models that can produce and consume power, gas, and thermal energy including hybrid distributed power sources, and suggests action plans.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.1-23
• /
• 2017

Organizational culture among flight crews has a profound impact on the individual attitude and behavior of member flight crews, and active training is conducted focusing on improving flight crews' Crew Resource Management(CRM) performance. However, adequate research and training on the relationships between flight crew's individual culture and CRM performance have not been conducted. Hence, this study examined the effect of individual cultural values on CRM performance and the moderation effect of psychological safety, with captains and first officers working for commercial airlines as participants. For the factors related to individual cultural value scale, power distance had no significant effect on CRM performance, uncertainty avoidance had a significant negative effect, and individualism had a significant positive effect. With regard to the moderation effect of psychological safety on the relationships between individual cultural values and CRM performance, a significant interaction was found between power distance and CRM performance, but not between uncertainty avoidance and CRM performance, or between individualism and CRM performance. Power distance and CRM performance exhibited a strong negative correlation in case of low psychological safety. Compared to existing research measuring the cultural characteristics of pilot groups on a national or organizational culture level, this study is uniquely valuable in that it also covers the relationship between individual cultural values of commercial airline flight crews and CRM performance.

• Environmental and Resource Economics Review
• /
• v.21 no.3
• /
• pp.543-572
• /
• 2012

This paper compared historical energy use from 2000 between Japan and Korea and reviewed literature of mid-and long-term low carbon energy scenarios and plans in both countries released since 2000. In terms of energy use pattern, there are similarities between Korea and Japan; high dependence on energy imports, high proportion of manufacturing industry among OECD countries, closed electricity system disconnected with foreign countries, and high proportion of nuclear power generation with low proportion of renewable electricity despite of high potential of renewable energy. Differences are as follows; decreasing trend in Japan and increasing trend in Korea in terms of energy demand and supply, difficulty of exchanging electricity between regions in Japan unlike Korea, and prospect of nuclear power, that is, curtailing in Japan while expanding in Korea according to governmental plan. Energy Basic Plan in both countries established before nuclear accident in Fukushima required expanding about two times of nuclear energy by 2030, while civil society's energy scenarios suggested reducing energy demand, phasing-out nuclear power, and expanding renewable energy. This paper will serve as a base for future studies about long-term energy scenarios and plan in Japan and Korea.

• Journal of Communications and Networks
• /
• v.2 no.1
• /
• pp.5-17
• /
• 2000

cdma2000 offers several enhancement as compared to TIA/EIA-95, although it remains fully compatible with TIA/EIA-95 systems and allows for a smooth migration from one to the other-Major new capability include:1)connectivity to GSM-MAP in addition to IP and IS-41 networks; 2) new layering with new LAC and MAC architectures for improved service multiplexing and QoS management and efficient use of radio resource ;3) new bands and band widths of operation in support of various operator need and constraints, as well as desire for a smooth and progressive migration to cdma 2000; and 4) flexible channel structure in support of multiple services with various QoS and variable transmission rates at up to 1 Mbps per channel and 2 Mbps per user. Given the phenomenal success of wireless services and desire for higher rate wireless services. improved spectrum efficiency was a major design goal in the elaboration of cdma2000. Major capacity enhancing features include; 1) turbo coding for data transmission: 2)fast forward link power control :3) forward link transmit diversity; 4) support of directive antenna transmission techniques; 5) coherent reverse link structure; and 6) enhanced access channel operation. As users increasingly rely on their cell phone at work and at home for voice and data exchange, the stand-by time and operation-time are essential parameters that can influence customer's satisfaction and service utilization. Another major goal of cdma2000 was therefore to enable manufacturers to further optimize power utilization in the terminal. Major battery life enhancing features include; 1) improved reverse link performance (i.e., reduced transmit power per information bit; 2) new common channel structure and operation ;3) quick paging channel operation; 4) reverse link gated transmission ; and 5) new MAC stated for efficient and ubiquitous idle time idle time operation. this article provides additional details on those enhancements. The intent is not to duplicate the detailed cdma2000 radio access network specification, but rather to provide some background on the new features of cdma2000 and on the qualitative improvements as compared to the TIA/EIA-95 based systems. The article is focused on the physical layer structure and associated procedures. It therefore does not cover the MAC, LAC, radio resource management [1], or any other signaling protocols in any detail. We assume some familiarity with the basic CDMA concepts used in TIA/EIA-95.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.10A
• /
• pp.1057-1064
• /
• 2007

Cognitive radio(CR) technique which utilizes empty frequency bands allocated to private business but not being used temporally has been researched. According to the standard, CR users detect the primary user using the same channel, CR users should move to the another channel to guarantee the primary user's decodability. Thus, CR systems cannot use the same channel and support the CR user's QoS(Quality of Service) during the channel moving time. In this paper, we propose a radio resource sharing method that CR basestation controls the transmission power with the primary user's SNR(Signal to Noise Ratio) to increase the spectral efficiency of area and to minimize the outage of CR users. In addition, computer simulation demonstrates show that the proposed method improved spectral efficiency of area and decreased outage probability of CR users.

• Environmental and Resource Economics Review
• /
• v.21 no.1
• /
• pp.3-25
• /
• 2012

Generally speaking, firms, faced with a regulatory environment, are likely to use more or less inputs than optimal level due to allocative inefficiency of inputs. This paper, first, tests allocative efficiency of fuel inputs and calculates the divergence between the actual and optimal levels of each fuel input conditional on the optimal level of capital stock in Korean thermal power industry. Then, given that each fuel is efficiently allocated. potential reduction of $CO_2$ is estimated over the period 1987~2008. The null hypothesis of allocative efficiency with respect to all fuels is rejected, indicating that thermal power plants fail to attain cost minimization subject do market prices. Allocative efficiency between each pair of fuels is also tested; efficient uses of fuels relative to each other are all rejected. Empirical results indicate that coal and gas are used more and oil is used less than optimal level. On average, more than 10 million tons of $CO_2$ per year could be reduced by achieving allocative efficiency of fuels.

• Journal of the Korean Geographical Society
• /
• v.44 no.5
• /
• pp.647-660
• /
• 2009

Although tourism has been quite popular as development strategy, the outcomes may vary dependent upon managing stakeholders involved. Thus, stakeholder management has been the subject of growing research interests recently. Collaboration theory was suggested as an alternative to this question; however, collaboration theory may provide potential benefits, it lacks in consideration into stakeholder power relations. The purpose of this paper is two foleded. One is to examine critically collaboration theory in the context of tourism development, and address the necessity of stakeholder analysis framework, and the other is to provide the framework. This paper argues that careful analysis of stakeholders from diverse perspectives should be done in advance, and presents stakeholder analysis framework which consists of six analysis indicators: interest, perspective, power base(resource), involvement, influence, and legitimacy. The framework consists of three stages: (1) identifying stakeholder, (2) assessing stakeholder, and (3) establishing strategies. It is argued that the framework in this paper can be useful to analyze stakeholders and to set up strategy for more collaborative tourism development.

• Environmental and Resource Economics Review
• /
• v.19 no.2
• /
• pp.243-282
• /
• 2010

In this paper, we analyze the components and trends of carbon emissions using the Logarithmic Mean Divisia Index decomposition method in Korean electricity industry during the period 1991~2007. In the demand side, carbon emissions are affected by electricity intensity and structural shift and especially electricity intensity is identified as the major factor which has lead carbon emissions decreasing. In the supply side, the result in variations of carbon emission for electric power generation depends on the influences of fossil fuel mix, fuel intensity, generation mix and so on. As a result fuel intensity is the most negative effect on both carbon emission intensity and the amount of carbon emission while the change of generation mix has a positive effect on increasing carbon emissions. And to conclude it needs to make the strategic policies to improve electricity intensity in the demand and to rise emission efficiency as well as to substitute thermal power generation in supply side.

• Environmental and Resource Economics Review
• /
• v.27 no.1
• /
• pp.161-194
• /
• 2018

This study examines performances of cooperatives relative to investor-owned firms in the US electric power industry. Using a panel data of firms from 2001 to 2014, the results show that cooperatives operate under conditions of more difficult capital constraints associated with the higher cost of debt and limited access to external equity capital. While investor-owned utilities, especially the large utilities that are less capital constrained, take benefits from substantial scale economies existing in the industry, the marginal cost of operation substantially increases with output for cooperatives. I do not find differences in profitability between the two ownership structures, measured by return on assets and return on equity. Plant capacity utilization, which is a measure of plant efficiency conditional on the operation, is also not statistically different between the two groups.

• Environmental and Resource Economics Review
• /
• v.31 no.2
• /
• pp.141-163
• /
• 2022

This paper empirically analyzes the effect of renewable electricity generation on the System Marginal Price (SMP) in Korea. Using an ARX-GARCHX model with hourly data from 2016 to 2020, we evaluate SMP determinants and merit order effects. As a result, we find that solar and wind power, as well as gas price and total load, play a critical role in the SMP. In particular, solar power reduces the SMP level but raises volatility during peak and off-peak periods. This result implies that SMP may fall as renewable electricity generation increases, leading to a decrease in the profitability of existing power plants and investment in renewables. On the other hand, even if the subsidy of renewable energy increases the burden on the SMP, it can be offset by the merit order effect, which lowers the SMP.