• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.27-33
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• 2008

In this paper, we propose a cognitive beamforming scheme for coexistence of CR (Cognitive Radio) and IR (Incumbent Radio) systems. In order to maintain the priority of the IR in spectrum utilization the proposed cognitive beamforming scheme needs to have the CR not cause any interference to the IR systems occupying the same frequency band at the same time. In addition the proposed scheme has to provide maximum channel gain to the CRU (CR User) in a boundary of satisfying the former criterion. For this purpose, the proposed scheme does not cause any interference to the IRU (IR User), while the CRU is served without additional radio resource consumption. From simulation, we confirmed that when using the proposed scheme the CRU does not interfere with the IRU and there is little bit error rate performance degradation of the CRU as compared to that of the ideal beamforming system, which does not consider the IR priority.

• Korean Journal of Agricultural Science
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• v.29 no.1
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• pp.55-65
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• 2002

The most representative fruit in Yanbian area is Applepear(Ping Guo Li). It has been a important resource of farm income. According to the economic growth and income Increase of individual consumers, food consumption pattern will be changed from grain to high value cash crops such as Applepear and vegetables. The globalization and adapt ion of free market oriented economic policy of China government have led to change the collective farming system to individual farm management system. The institutional transformation have brought about high productivity of farm products and incomes of farmers. Therefore the plantation area of Applepear and requirement of investment cost for establishment of Applepear farms have increased rapidly since the 1980's, the time of perestroika and glasnost in Chinese economy. In prosperity of Chinese agriculture, individual farmer's decision making as free selection of farmland use, selection of high pay-off crops, free sale of the products in free market and credit support for the project might be the most important factors. In case of Applepear farm development, net present value of the project net benefit was estimated at 55.518won per hectare and financial rate of return was 21%. The benefit/cost ratio of the project was 2.11. Considering 10% of discounting rate or the opportunity cost of capital in China the Applepear farm development project showed us economically feasible in the light of the above efficiency indices. The Chinese government has to support Applepear farm development project financially and institutionally considering the high-payoff benefit of the fruit and farmer's in come increase in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1066-1074
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• 2008

In this paper, we proposed an efficient algorithm using pulse signal based on group-node-contention in LR-WPAN. The purpose of IEEE 802.15.4 is low speed, low cost and low power consumption. Recently, as applications of LR-WPAN have been extended, there is a strong probability of collision as well and almost collision occurs because of hidden node problem. Moreover, if the collision continuously occurs due to hidden node collision, network performance could be decreased. Nowadays, although several papers focus on the hidden node collision, algorithms waste the channel resource if continuous collisions frequently occur. In this paper, we assume that PAN has been already formed groups, and by using pulse signal, coordinator allocates channel and orders, and then, nodes in the allocated group can compete each other. Hence, contention nodes are reduced significantly, channel wastage caused by collision is decreased, and data transmission rate is improving. Finally, this algorithm can protect the network from disruption caused by frequent collisions. Simulation shows that this algorithm can improve the performance.

• The Journal of Fisheries Business Administration
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• v.51 no.4
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• pp.19-45
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• 2020

This study is to evaluate economic effect of the creation project of snow crab, Chionoecetes opilio, spawning and habitat ground in Uljin and Youngdeok county. The main results of this study are summarized as follows: first, 14,400 million won was invested in the creation project cost of Chionoecetes opilio spawning and habitat ground of Uljin and Youngdeok County from 2015 to 2020. Second, the creation project of Chionoecetes opilio spawning and habitat ground directly provides fishing benefits, festival benefits, research and development benefits and employment benefits. Third, on the basis of above benefits, the creation project of Chionoecetes opilio spawning and habitat ground has net present value of 29,900.53 million won, internal rate of return 16.9%, and benefit-cost of 2.91 under a 4.5% social discount rate. Also, the creation project creates 195 jobs. This indicates that the creation project of Chionoecetes opilio spawning and habitat ground not only contributes to the increase in the income of coastal fishery and fishing villages but also to the job making. The result of this study provides useful information to policy makers or project managers as it shows that the project to create spawning and habitat ground should be carried out in consideration of the resource and biological characteristics of individual fish and that economic assessment logic should also be developed based on this. Also, it proves that the project to create a snow crab spawning and habitat ground is a national and local infrastructure project that increases the actual fishing income in the region. At the same time, it maintains the reproducibility function of most fish species, along with enhancing the people's benefits such as fishing village tourism and marine product consumption. Moreover, it provides useful information on budgeting for the continuous development of snow crab spawning and habitat ground in the mid to long-term.

• Environmental and Resource Economics Review
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• v.19 no.4
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• pp.733-752
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• 2010

This study applies the Luenberger indicator approach to estimate productivity of the Korean fossil-fueled power plants. A panel data set of 25 power plants was used. The method incorporates $CO_2$ emission as an undesirable output and shows that ignoring $CO_2$ emission overestimates the productivity change. There are two sources of overestimation. First, the usual method estimates productivity change ignoring the increase in $CO_2$ emission that occurred during the study period. Second, the productivity change estimated by the usual method that does not incorporate $CO_2$ emission is very sensitively affected by the change in operation rate. The paper decomposes the productivity change into the efficiency change and the technical change. The results show that the two sources contribute to the productivity change almost equally. It is also shown that the size and the pattern of productivity change are dependent on the plants' fuel types. Non-LNG power plants which saved their energy consumption and thereby reduced their $CO_2$ emission have achieved relatively high rate of productivity improvement.

• Environmental and Resource Economics Review
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• v.31 no.2
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• pp.165-204
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• 2022

This study organized data from 2000 to 2014 for 20 grid-connected countries in Europe and analyzed the determinants of carbon emissions through the panel GLS method considering the problem of heteroscedasticity and autocorrelation. At the same time, the effect of introducing ETS was considered by dividing the sample period as of 2005 when the European emission trading system was introduced. Carbon emissions from individual countries were used as dependent variables, and proportion of generation by each source, power self-sufficiency ratio of neighboring countries, power production from resource-holding countries, concentration of power sources, total energy consumption per capita in the industrial sector, tax of electricity, net electricity export per capita, and size of national territory per capita. According to the estimation results, the proportion of nuclear power and renewable energy generation, concentration of power sources, and size of the national territory area per capita had a negative (-) effect on carbon emissions both before and after 2005. On the other hand, the proportion of coal power generation, the power supply and demand rate of neighboring countries, the power production of resource-holding countries, and the total energy consumption per capita in the industrial sector were found to have a positive (+) effect on carbon emissions. In addition, the proportion of gas generation had a negative (-) effect on carbon emissions, and tax of electricity were found to have a positive (+) effect. However, all of these were only significant before 2005. It was found that net electricity export per capita had a negative (-) effect on carbon emissions only after 2005. The results of this study suggest macroscopic strategies to reduce carbon emissions to green growth, suggesting mid- to long-term power mix optimization measures considering the electricity trade market and their role.

• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.3940-3955
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• 2023

A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: ⁶⁰Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.65-78
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• 2018

According to the in social aspects such as population growth, urbanization and industrialization, development of livestock industry by meat consumption, amount of organic wastes (containing sewage sludge and food waste, animal manure, etc) has been increased annually in South Korea. Precise monitoring of 11 organic wastes biogas facilities were conducted. The organic decomposition rate of organic wastewater was 68.2 % for food wastes, 66.8 % for animal manure and 46.2 % for sewage sludge and 58.8 % for total organic wastes. As a result of analyzing the biogas characteristics before and after the pretreatment, the total average of the whole facility was measured to be 560 ppm using iron salts and desulfurization, and decreased to 40 ppm when the reduction efficiency was above 90 %. Particularly, when iron salt is injected into the digester, the treatment efficiency is about 93 %, and the average is reduced to 150 ppm. In the case of dehumidification, the absolute humidity and the relative humidity were analyzed. The dew point temperature of the facility where the dehumidification facility was well maintained as $14^{\circ}C$, the absolute humidity was $12.6g/m^3$, and the relative humidity was 35 %. Therefore, it is necessary to compensate for the disadvantages of biogasification facilities of organic waste resources and optimize utilization of biogas and improve operation of facilities. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure) through precision monitoring.

• The Korean Journal of Community Living Science
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• v.16 no.1
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• pp.149-163
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• 2005

Family has emerged as a key concept for health, and it has been identified as one of the most important conditions. The relationship between health habit and its management is different depending on family. The odd pair family, mostly rural lower income class, worry to have poor health because of no spouse and small family size. One thousand eight hundred and seventy(1870) subjects were collected in 9 provinces through the sampling of Probability Proportional to Size (PPS). Questionnaire method was conducted on health checking, bath states, alcohol consumption, cigarette smoking, and the prevalence of farmer's health related problems. The main results were as follows: 1) The characteristics of odd pair families are that the head of household is female(77% ), the size of family is small(1.76 persons), the education level is low(7.5 years for male, 3.1 years for female) and the age group is old (male: 89.78 year old, female: 73.69 year old). 2) For the odd pair family, the frequency of health checking is quite low with one or two times per year(l0.2%) and the rate of no-health checking is much higher(35.8%) .3) Bathing utility is not available 29.6% of the odd pair family and only cold water is supplied at home for the 11.5 % of them. However, for the paired family, 9.8 % of them has no bathing utility and the rate of the family supplied with only cold water is just 7.9%. 4) The bathing frequency score of odd pair family is l.74points for male and 1.25 points for female. 5) The rate of smoking habits for odd pair family is 68.5 % and specially it is 7.6% for female, which is higher comparing with that of pair family. 6) The smoking frequency score of odd pair family is 1.57 points. 7) Alcohol drinking frequency score of odd pair family is 1.79 points for male, and 3.24points for female. 8) Farmers' syndrome(FS) revealed 38.7% of odd pair family and it is lower than that of pair family(57.3%). Special pain of FS was huckle bone and muscle(28.4%) and articular pain(24.l %). The pain rate of huckle bone and muscle(43.l %) and articular pain(33.5%) were higher in a year in odd pair family were lower than those of pair family: farming machine caused accidents(6.5%) and pesticide poisoning(5.7%). l0) The odd pair family use more frequently medical clinic or public health center for the treatment of FS(74.7%) and pesticide poisoning(62.5%) than the pair family for FS(69.0%) and for pesticide poisoning(.53.6%). The score of FS treatment is 5.70 points for odd pair family and it is not significantly different from 5.62 points of the paired family. The result of pesticide poisoning treatment score is as same as that of FS.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.8
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• pp.27-34
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• 2012

In this paper, the implementation of high throughput two-dimensional (2-D) $8{\times}8$ forward and inverse integer DCT transform for H.264 is presented. The forward and inverse transforms are represented using simple shift and addition operations. Matrix decomposition and matrix operation such as the Kronecker product and direct sum are used to reduce the computation complexity. The proposed design uses integer computations and does not use transpose memory and hence, the resource consumption is also reduced. The maximum operating frequency of the proposed pipelined architecture is 1.184 GHz, which achieves 25.27 Gpixels/sec throughput rate with the hardware cost of 44864 gates. High throughput and low hardware makes the proposed design useful for real time H.264/AVC high definition processing.