• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.1
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• pp.100-113
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• 2018

The Proximity Service, which is one of the most popular network capacity improvement methods, uses the frequency reuse in order to increase the frequency efficiency. As a result, inter-cell interference between cellular and proximity service users occurs at a cell edge. In this paper, we proposed a mitigation scheme for inter-cell interference, where we suggested a new function of and eNB with ProSe function exchanging information about ProSe parameters and ProSe user equipment with neighboring cells via the X2 interface. As the first step, the resource which did not cause the inter-cell interference problem were pre-allocated through the frequency sensing in the ProSe direct discovery. As the next step, the inter-cell interference problem was solved by reallocating appropriate resources based on the ProSe application code, the ProSe application QoS, the ProSe application ID and validity timer in ProSe direct communication.

• Environmental and Resource Economics Review
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• v.15 no.1
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• pp.95-133
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• 2006

This research first reviewed and analysed the current domestic situation of the voluntary agreement implementation and then it developed the policy implementation scenarios which will be applied to the model, KORTEM_ V.2. The model, consisted with 83 industries and commodities, examined the economic and environmental impacts of this policy instrument. Depending on the efforts of participating sectors and agents for fuel substitution and energy efficiency improvement, it has been evaluated that the voluntary agreement could be the "no-regret" policy. In other words, if the participating sectors and agents can achieve the voluntary energy conservation and emission reduction target without the negative impact on output level, the reduction of national emission will be achieved by creating the economic benefit, simultaneously. Therefore, for the successful implementation of voluntary agreement, this study emphasized the importance of expansion and strengthening of the current financial and institutional support for participating sectors and agents.

• Environmental and Resource Economics Review
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• v.23 no.2
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• pp.349-364
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• 2014

This study analyzed Granger causality between power consumption and production activity in manufacturing sector, by using error correction model. It found that there exists the connection between power consumption and production activity in manufacturing sector. By reflecting the industrial characteristics, it found not only the bilateral causality (power consumption ${\leftrightarrow}$ production activity) in power non-intensive industry, high value-added industry and low value-added industry, but also one-way causality (power consumption ${\rightarrow}$ production activity) in power-intensive industry. These results imply that power demand management policy focusing on efficiency improvement is necessary primarily to minimize negative impacts on production activity, and also stable power supply system is required to meet the increase of power demand.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Environmental and Resource Economics Review
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• v.19 no.2
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• pp.215-242
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• 2010

This study constructs a bayesian neoclassical DSGE model that applies oil usage. The model includes technology shocks, oil price shocks, and shocks to energy policies as exogenous driving forces. First, this study aims to analyze the roles of these exogenous shocks in the Korean business cycle. Second, this study examines the effects of long-term changes in the energy consumption structure, including the reduction in oil use as a share of energy consumption and improvement in oil efficiency. In the case of oil price shocks, results show that these shocks exert recessionary pressure on the economy in line with those obtained in the previous literature. On the other hand, shocks to energy policies, which reduce oil consumption per capital, result in opposite consequences to oil price shocks, decreasing oil consumption. Also, counterfactual exercises show that long-term changes in the energy consumption structure would mitigate the contractionary effects of oil price shocks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.19-25
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• 2008

When there are numerous wireless communication systems co-existing in the limited available frequency resource, an unexpected time delay can be caused during the system switching. So, in order to reduce this time delay, a mode selection method is required. In this paper, we propose a mode selection method to minimize the time delay for multi-system wireless communication systems. For the sake of efficiency, the mode selection method is designed by analyzing the preamble characteristics of different standards. Instead of performing a full search, we propose the preamble partial search to reduce the time delay to a minimum. Simulated with Matlab in an additive white Gaussian noise(AWGN) environment with a signal to noise ratio(SNR) of 10dB and bit error rate(BER) of $10^{-6}$, we evaluated and showed the performance improvement gained by using our proposed mode selection method.

• Journal of Agricultural Education and Human Resource Development
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• v.49 no.4
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• pp.43-65
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• 2017

The purpose of this study is to identify the Issues of the survey on employment status at the vocational high school. For this, 19 chief teachers of employment department were interviewed with the validity of the concept of employment, the appropriateness of the survey period, the effectiveness of the survey method, and the usefulness of the survey output. The main results of research were as follows. First, in the survey of current employment situation, employment is a low standard to be recognized as an ordinary standard, and the employment counts not linked to DB are likely to be inaccurate. Second, regarding the period of employment, the current February survey is difficult to distinguish between field study and employment, and there is a limit to the study of full employment. Third, the present method has limitations on reliability and work efficiency in the survey method. Fourth, current output is not useful for school use in relation to survey output.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.76-83
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• 2012

In this study, the research examined the effect on FC, WG, RP replacement ratio on the quality improvement of BS mortar using the RA. First of all, the flow value increased as the FC contents increased, and decreased as the WG and RP contents increased. The air contents was reduced as the FC and RP contents increased, but was increased as the WG contents went up While the compressive strength of 1 : 7 mix proportion increased with the increase of the FC and WG contents, it decreased as there was more RP contents. The compressive strength of RP could increase as the mix proportion increased, but the difference depending on the improvement material type and replacement ratio decreased gradually. The absorption deteriorated as the FC and RP contents increased in all the mix proportions, but improved a little when WG was used. Meanwhile, the absorption decreased as the compressive strength improved in all the mix proportions as a correlation, but the order was FC, RP and WG depending on the quality improvement material types. The FC and WG were most favorable in terms of quality improvement as a total analysis, and the RP and WG was most effective in terms of economical efficiency and resource recycling.

• Journal of the Korean Society for information Management
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• v.31 no.1
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• pp.119-141
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• 2014

To enhance its efficiency to improve organizations' competitiveness, performance evaluation is vital and it influences budget, policies, and human resource affairs of the organizations. The study aims to develop performance indicators for National Library of Korea (NLK) and evaluate performance based on indicators driven. As a result, the study develops 2 viewpoints for each work area of NLK - management of information system, digital resources enlargement, and the cooperative utilization system for alternative materials. It also develops total 12 indicators. Based on the evaluation;the research finally suggests strategies for performance improvement by viewpoints for NLK.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.29-36
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• 2009

In this paper, we proposed auto exposure(AE) algorithm and hardware implementation for apply to mobile phone camera. AE is a function that control camera exposure automatically for appropriate to object. Existing AE is using micro controller unit and there are some problems about high expense and slow processing speed. For improve these problems, we proposed AE algorithm for hardware implementation without micro controller unit therefor we can expect improvement about the content of a production and operation speed. We proposed the algorithm that is considered efficiency of hardware resource and the results of hardware implementation of proposed AE algorithm apply to mobile phone camera sensor, we verified proposed AE function.