• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.909-930
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• 2022

Although the electricity tariff for each customer class in Korea has an institutional basis which can be linked to cost fluctuations caused by the increase in fuel cost, there is a situation in which it cannot be raised in a timely manner, considering the national economic burden such as inflation. There can be some disagreements about unconditionally raising electricity rates when cost increases occur. It is, however, well known that Korean domestic electricity rates are very low around the world and are in an environment in which rates are not easily adjusted. Moreover, as Korean electricity rates cannot be easily raised due to various factors, domestic electricity rates for each customer class itself have not delivered a desirable price signal for power consumption. Based on historical data such as fuel costs and power production by power source from 2017 to 2020, this study estimated how much power consumption would change if electricity rates were adjusted in 2030 and price signal distortion was resolved. As a result of the estimation, power consumption will be reduced by 9,000 GWh if the current electricity bill is adjusted to a level which can be 100% recovered even with the supply cost alone. This led to a reduction of about 3.82 million CO₂tons of greenhouse gas emissions in the Korean power sector.

• Resources Recycling
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• v.33 no.2
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• pp.62-72
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• 2024

Although the Paris Agreement in 2015 aimed to limit global temperature increases to below 2℃ and eventually to 1.5℃ to address the climate crisis, global temperature continues to rise. Developed countries have proposed a circular economy as a major strategy to tackle this issue. Detailed implementation methods include reusing, remanufacturing, recycling, and energy recovery. Remanufacturing has a greater potential to achieve high added value and carbon neutrality than other resource circulation methods. However, currently, no standardized method for quantitatively evaluating the greenhouse gas (GHG) reduction effects of remanufacturing exists. This study compares and analyzes recent research trends since 2020 on the calculation of GHG emission reduction effects from remanufacturing. It also examines international standards for environmental impact assessment, including GHGs and environmental performance labeling systems. This study derives the key factors for standardizing the calculation of the GHG emission reduction effects of remanufactured products.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.623-639
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• 1995

We have never seen any method to cope basically with complicated situation and problems around medical reimbursement rates here in Korea since 1977 witnessed by the beginning of medical insurance. By the way researchers concerned are beginning to propose some kinds of innovative and detailed ideas to government these days. They are Diagnosis-related group(DRG) and Resource-based .elative value scale(RBRVS). In the light of this situation it is so encouraging that our government can come up with that and move. In case of RBRVS research we have already been reaching even to the level of reviewing and revising methodology for its further development after naive pilot study on internal medicine and general surgery last year. However there might be something different conditions between USA and Korea to apply the same Dr. Hsiao's method and it must be vital to check so called' total work approach' compared with 'intra-service work approach' before expanding to the whole medical fields. According to the' Intra-service approach', the physician's work is supposed to be divided into three sub-works by the name of intraservice work, pre, and post service work. These sub-works, again should be merged together to be the pre-postwork subset through some statistical methods of the estimation process applied by Dr. Hsiao's methodology in RBRVS development later on. But in this paper that estimation process was not taken because we could have real values for all of those surveyed items related to just one specialty, OB & GY. Instead, We used some statistical comparison procedures relevant to demographic characteristics, reliability & validity and correlation analysis with American RVU(Relative value unit) between the total work and merged total work from intraservice work approach. The unit of analysis was individual physicians of OB & GY and 300 physicians were selected for each approach through statistical sampling method based on national population of OB & GY physicians in Korea. And also with the thankful help of Advisory Committee under Korean Association of OB & GY, questionnaires were made and mailed to the subjects, two times. As a result there were not any statistically significant differences in demographic characteristics between the two approaches except for the variable 'Response time for the questionnaires', but in other sections of comparisons, response rate, representative values, reliability & validity test, correlation analysis with American RVU, all showed 'Total approach' was not only more rational and statistically meaningful than 'Intra-service approach' but also had considerable merits. But we are not absolutely sure about this paper's robustness. Because of some limitations, we'd rather like to suggest further researches should be followed. In that sense the first thing would be a research for the influence of doctor's characteristics, especially 'frequency' on the rating of work and the way to define total work more clearly.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.528-539
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• 2005

The H.264 has been adopted as the video codec for various multimedia services such as DMB and next-generation DVD because of its superior coding performance. However, the reference codec of the standard, the joint model (JM) contains quite a few algorithms which are too complex to be used for the resource-constraint embedded environment. This paper introduces very low-complexity H.264 encoding algorithm which is applicable for the embedded environment. The proposed algorithm was realized by restricting some coding tools on the basis that it should not cause too severe degradation of RD-performance and adding a few early termination and bypass conditions during the motion estimation and mode decision process. In case of encoding of 7.5fps QCIF sequence with 64kbpswith the proposed algorithm, the encoder yields worse PSNRs by 0.4 dB than the standard JM, but requires only $15\%$ of computational complexity and lowers the required memory and power consumption drastically. By porting the proposed H.264 codec into the PDA with Intel PXA255 Processor, we verified the feasibility of the H.264 based MMS(Multimedia Messaging Service) on PDA.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.463-472
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• 2015

Solar radiation data are important data that can be used as basic research data in diverse areas. In particular, solar radiation data are essential for diverse studies that have been recently conducted in South Korea including those for new and renewable energy resource map making and crop yield forecasting. So purpose of this study is modification of Heliosat-II method to estimate solar irradiance in Korea by using COMS-MI imagery. For this purpose, in this study, errors appearing in ground albedo images were corrected through linear transformation. And method of producing background albedo map which is used in Heliosat-II method is modified to get more finely tuned one. Through the study, ground albedo correction could be successfully performed and background albedo maps could be successfully derived. Lastly, In this study, solar irradiance was estimated by using modified Heliostat-II method. And it was compared with actually measured values to verify the accuracy of the methods. Accuracy of estimated solar irradiance was 30.8% RMSE(%). And this accuracy level means that solar irradiance was estimated on 10% higher level than previous Heliosat-II method.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.2
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• pp.48-55
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• 2011

Solar radiation components reflected by the sea surface ($R_{ss}\uparrow$) are additional energy sources comprising the solar radiation regime. Previous studies, based on observational approaches, indicated that $R_{ss}\uparrow$ is an available climatological resource. However, an estimation process for $R_{ss}\uparrow$ has not been established. In this case study over Jeju Island in South Korea, we applied a new estimation process to solar radiation modeling and discussed the spatial distribution of $R_{ss}\uparrow$ and its seasonal variation. Our results showed that the illuminated area and the intensity of $R_{ss}\uparrow$ became greatest at the winter solstice and least at the summer solstice. We estimated the illuminated area of $R_{ss}\uparrow$ as it expanded over the southern slope of Jeju Island. At the winter solstice, on a daily basis, the area and intensity of illumination by $R_{ss}\uparrow$ were $182.3km^2$ and $0.41\;MJ\;m^{-2}\;day\;{-1}$, respectively. Comparing the daily accumulative and instantaneous values of $R_{ss}\uparrow$ intensity, the difference was about 20 times greater in daily cases than in instantaneous cases. On the other hand, for instantaneous values, the $R_{ss}\uparrow$ intensity accounted for up to 33% of the three components, i.e., direct, diffuse and reflected radiation in winter solstice. In addition, it was estimated that the sea surface reflectance depended on the wind speed. Therefore, in a practical use of this revised model, wind conditions should be considered as a critical factor in estimating $R_{ss}\uparrow$.

• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.46-54
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• 2018

In the 21st century, the Earth has continued its efforts to reduce carbon emissions to overcome the crisis caused by climate change. The construction industry, which is a representative industry that produces large amounts of the environmental load during construction, should actively reduce the amount of the environmental load. From the planning stage of the construction facility, it is necessary to consider the environmental load such as route selection and structure type selection to reduce the environmental load. However, the environmental load can be estimated based on the input resource amount. However, in the planning stage, it is difficult to accurately calculate the environmental load due to lack of information on the construction amount. The purpose of this study is to select the environmental load factors for IPC girder bridges to be used in the environmental load estimation model in the planning stage. Specific information related to the environmental load was selected from a list of information available in the planning stage, reflecting the Life Cycle Assessment(LCA), correlation, principal components analysis and expert opinion. The list of selected planning stage information is 10 such as span length and bridge extension, and it is expected to be used as a basic data for the future development of environmental load estimation model.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.273-280
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• 2005

Robust magneto-telluric (MT) response function estimators are now in standard use in electromagnetic induction research. Properly devised and applied, these methods can reduce the influence of unusual data (outlier) in the response (electric field) variable, but often not sensitive to exceptional predictor (magnetic field) data, which are termed leverage points. A bounded influence estimator is described which simultaneously limits the influence of both outlier and leverage point, and has proven to consistently yield more reliable MT response function estimates than conventional robust approach. The bounded influence estimator combines a standard robust M-estimator with leverage weighting based on the statistics of the hat matrix diagonal, which is a standard statistical measure of unusual predictors. Further extensions to MT data analysis are proposed, including a establishment of data rejection criterion which minimize the influence of both electric and magnetic outlier in frequency domain based on statistical distribution of electromagnetic field. The rejection scheme made in this study seems to have an effective performance on eliminating extreme data, which is even not removed by BI estimator, in frequency domain. The effectiveness and advantage of these developments are illustrated using real MT data.

• Geophysics and Geophysical Exploration
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• v.21 no.1
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• pp.54-60
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• 2018

The data acquired from seismic exploration can be used to detect the existence of oil and gas resources through appropriate processing and interpretation. The seismic attributes indicating the existence of resources are extracted from amplitude information, where the Q-factor representing intrinsic attenuation plays an useful role of hydrocarbon indicator. So, the accuracy of Q-factor estimation is very important to investigate the existence of resources. In this study, we calculated the Q-factor and analyzed the error rate through a numerical example. To mimic real data, random noise was added to the synthetic data. With the noise-added data, the Q-factor was estimated and the error rate was analyzed by using the spectral ratio method (SRM) and peak frequency shift method (PFSM). Both methods provided a relatively accurate Q-factor when the signal-to-noise ratio was 90 dB. However, the peak frequency shift method (PFSM) produced better results than the spectral ratio method (SRM) as the level of random noise increased.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.10-21
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• 2015

Cellular Network assisted device-to-device (D2D) communication has been growing to reduce the overload of eNodeB and mitigate the frequency shortage. However, by sharing the uplink frequency resource with the cellular network, the interference between cellular and D2D is increased. In this paper, we propose the advanced receiver based on soft decision to reduce the interference between cellular and D2D. The proposed receiver can suppress and cancel the interference by calculating the unbiased estimation value of interference signal using minimum mean square error (MMSE) or interference rejection combing (IRC) receiver. The interference signal is updated using soft information expressed by log-likelihood ratio (LLR). We perform a system level simulation based on the 20-MHz bandwidth of the 3GPP LTE-A system. Simulation results show that the proposed receiver can improve SINR, throughput and spectral efficiency compared to conventional receivers.