• Journal of Sensor Science and Technology
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• v.11 no.3
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• pp.163-170
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• 2002

This paper proposes a $10\;{\mu}m$ thick oxide air-bridge structure which can be used as a substrate for RF circuits. The structure was fabricated by anodic reaction, complex oxidation and micromachining technology using TMAH etching. High quality films were obtained by combining low temperature thermal oxidation ($500^{\circ}C$, 1 hr at $H_2O/O_2$) and rapid thermal oxidation (RTO) process ($1050^{\circ}C$, 2 min). This structure is mechanically stable because of thick oxide layer up to $10\;{\mu}m$ and is expected to solve the problem of high dielectric loss of silicon substrate in RF region. The properties of the transmission line formed on the oxidized porous silicon (OPS) air-bridge were investigated and compared with those of the transmission line formed on the OPS layers. The insertion loss of coplanar waveguide (CPW) on OPS air-bridge was (about 2dB) lower than that of CPW on OPS layers. Also, the return loss of CPW on OPS air-bridge was less than about -20 dB at measured frequency region for 2.2 mm. Therefore, this technology is very promising for extending the use of CMOS circuitry to higher RF frequencies.

• Journal of the Korean Geographical Society
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• v.31 no.4
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• pp.648-661
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• 1996

The traditional von Thunen model has various shortcomings. Perhaps the greatest dificiency is the model's sole emphasis on the production side of the economy;that is, the agricultural markets are rarely closed for demand. In thes paoer a closed model for a three-activity, two-dimensional economy is developed. Equillibrium solutions are generated for prices, land areas, and outputs. Comparative static analysis then follows. Attention is next given to a maximum expected-return model under environmental uncertainty. Land uses for the traditional model and the closed model are then compared.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.236-246
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• 2014

Most countries have been promoted the legislative policy for the legal employment, causing a social conflicts by illegal immigrants in any countries. Despite the efforts to alleviate the illegal aliens, there are not nearly enough successful cases, and encounter a social problem about illegal stay worker. China is no exception. At present, the issue of China's foreign illegal employment is expected to be a social problem in the present and the future. However, the legislative policy against immigration control law and illegal foreign employment in China is very neglectful. There is a lack of adjusting rule of law on illegal foreign workers in China, and the remedy is also insufficient. It is necessary to secure a legal right for the protection of the Rights of illegal foreign workers based on the international norms. For this purpose, the illegal foreign workers related law should be enacted, and based on this, administration should be strengthened. The trend of major countries of illegal aliens is centered around an employer hiring strictly regulated. There is a need to have a strengthen regulation on the employer rather than the foreign workers in China. To this end, employer who hire illegal foreign workers should be required to receive considerable disadvantages such as penalties and fines, prison sentences, as well as various kinds of burdens and repatriation costs. It is necessary to run the voluntary repatriation(Freiwillige $R\ddot{u}ckehr$) program of illegal immigrants, and there is a need to take action for illegal immigrants who voluntary return home within a certain period are exempt from penalty. In conclusion, China must push ahead with a direction of positive policy in related ministries rather than sit on its hands on the wrong choice or a confusion of an employer and foreign workers with a policy on illegal foreign residents in limbo.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.10
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• pp.1008-1016
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• 2013

SAR measurement which was applied only to the mobile phone has been expanded in the Korean radio regulation law to the portable wireless communication equipments within 20 cm from the human body since Jan. 2012. The two-way radio operating at 150 MHz frequency band was newly included following the revised radio regulation in the target equipment of measurement. SAR measurement system at 150 MHz satisfying this regulation is necessary accordingly for SAR conformity assessment. The international SAR measurement standard(IEC 62209-2) includes the evaluation method on frequencies above 300 MHz, and the commercial SAR measurement system can measure SAR above 300 MHz only. The size of the reference dipole antenna(760 mm, return loss: -27.57 dB) and flat phantom ($1,300 mm(L){\times}900 mm(W){\times}200 mm(H)$), targeted SAR values for numerical analysis(1 g: 1.08 W/kg, 10 g: 0.77 W/kg) for SAR validation evaluation at 150 MHz frequency are proposed in this paper. The suggested dipole antenna and flat phantom are assembled and used to verify the conformity assessment of commercial SAR measurement system. The measured SAR values of 1 g and 10 g were obtained respectively to be 1.13 W/kg, 0.81 W/kg, and they satisfied the effective range(within ${\pm}10$ %) of IEC international standard. The standards based on this study are expected to be used for the domestic SAR measurement standard and IEC(International Electrotechnical Commission) international standard.

• The Journal of Fisheries Business Administration
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• v.29 no.1
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• pp.121-137
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• 1998

This study was conducted to examine the economic evaluation of the newly developed fish meal analog (BAIFA-M) in Korean rockfish feed. A raw fish feed (MP) and two commercially formulated diets (EP) were employed to compare weight gain (WG), feed conversion ratio (FCR) and survival rate (SR) from the sea cage culture system. By using the economic model in the practical sea cage culture system, feed cost, production cost and gross profit per kg production, rate of profit to gross revenue (RPGR), and internal rate of return (IRR) were calculated based upon the results of the experiment and the information of the private aquaculture farm (Young Chang) in Tong young, Korean. IRR criteria is one of the popular economic feasibility analysis methods applicable far aquaculture industry. This is an economic evaluation method to compare the given interest rate or the discount rate with IRR which can be calculated by the difference between the present value of the benefit stream and of the cost stream. The benefits of using EP on WG, FCR, SR, and production cost will be emphasized in this study. Fish averaging 20$\pm$3.6g (Mean$\pm$SD) were randomly distributed in each small cage (6m$\times$6m) as groups of 2,000 fish. By using 3 large size cages (12m$\times$12m), 12 small cages were constructed, and only 9 small cages were employed for three replicates of each diet treatment. To compare with MP diet, two sinking EP diets were designed by our laboratory and produced by the local feed company who wanted to promote these EP diets for the mass cage culture of Korean rockfish in the future. Two EP diets contain white fish meal and/or BAIFA-M as the main animal protein sources : WFM diet, maximum 43% of white fish meal : BAIEA- M diet, 30% of white fish meal nab replaced by BAIFA- M from WFM diet. Results are summarized in Table 1. Fish fed MP diet showed significantly lower SR than does fish fed two EP diets(P<0.05). However, there Were no significant difference on FCR among fish fed three practical diets. Table 1. Average feed conversion ratio (FCR), accumulative average survival rate (SR) and economic evaluation data far three practical diets. As we expected, BAIFA-M diet is more economical than WFM diet as well as MP diet. Feed cost and production cost per kg production from BAIEA - M diet were lower than those from WFM and MP diets. Moreover, gross profit per Kg production, RPGR and IRR from BAIFA- M diet were higher than those from WFM and MP diets. This economic evaluation study clearly indicated that MP diet should be replaced by the commerical formulated EP diets as soon as possible in the near future because MP diet is not economical in the practical sea cage culture system.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.71-75
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• 1985

The clinical state with EEG pattern similar to interval discharge of epileptics is named as latent epilepsy, which does not necessarily mean that the patient will develop epilepsy later. However, since there is possibility of developing epilepsy on later date, antiepileptic mainly dilantin was tried to control the abnormal EEG. Since January to October 1985, total 580 headache sases with more than moderately abnormal EEG Visited the Neurology clinic. Among them 162 cases with interval seizure pattern (ISP) of epilepsy were selected for the study. The main ISP was 1. diffuse theta and/or delta bursts and 2. spikes. Since the study is only analysis of clinical treatment of 162 cases Without previous planning based on financial aid, about 30% of the patients did not return after the 1st EEG examination, in 42% failed to follow the EEG after the treatment and only remaining 28% of the cases were studied. Among 29 patients who were treated with Dilantin 100mg tid po, 16 improved and 13 not. Of the 13, 4 showed partial Improvement and partial progression. Case 1. In 4 weeks of antiepileptic the ray (AR), spikes disappeared but in 2 months developed bursts. Case 2. In 17days of AR, spikes and bursts disappeared but in 3 months bursts reccured. Case 3. In 1 week of AR, bursts disappeared but spikes developed. Case 4. In 3 months of AR, no change of spikes and bursts and she discontinued the AR. In 6 months she developed grandmal seizure. Eighteen cases, treated with other drugs except antiepileptics, all showed improvement. The other drugs were vincaprol, polygammalon, aronamin, ATP and hydergine. The improved cases had spikes more often than theta bursts. In view of the small number of the cases due to dropping most patients out of present study, it is considered meaningless to perform statistical analysis. Further well planned study With more patients is to be expected.

• Journal of the Korean association of regional geographers
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• v.3 no.1
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• pp.99-113
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• 1997

The purpose of this study is to find out about the cause and adaptation process of urban households going to rural areas for agricultural management(Kwihyang nongga) through the microscopic analysis of a case study. Research results are summarized in the followings. The cause of Kwihyang nongga before the 1980s was generally due to the social causes like the support of dependent family or rural-to-urban migrants' maladjustment in urban society. After the 1980s, however, it was related to the economic reasons such as the increase of households' income by commercial agriculture more than the social ones. Most of Kwihyang nongga was traditionally the households which came back to their native places, rural areas. Recently the urban households which did not originally come from rural areas are going to rural space because of the cultivation of high profit oriented agricultural products. Recent Kwihyang nongga increased the size of commercial agriculture through leased farmland, not by a purchase of agricultural land. Even though the number of Kwihyang nongga is now a few, it is expected that the influence of Kwihyang nongga on rural society will be various and high because it consists of young generation. The increase of Kwihyang nongga may be one of the ways to mitigate the decreasing rate of utilization of agricultural lands due to the labor shortage of rural areas after industrialization. To solve rural problems related to underpopulation, it is necessary to establish the active plicies of helping Kwihyang nongga. The actions for Kwihyang nongga ought to emphasize the improvement of educational conditions and living facilities as well as financial aids and the improvement of farming conditions.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.105-114
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• 2013

Recently, Due to Climate change, extreme rainfall occurs frequently. In many preceding studies, Because of extreme hydrological events changes, it is expected that peak flood Magnitude and frequency of drainage infrastructures changes. However, at present, probability rainfall in the drainage facilities design is assumed to Stationary which are not effected from climate change and long-term fluctuation. In the future, flood control safety standard should be reconsidered about the valid viewpoint. In this paper, in order to assess impact of climate change on drainage system, Future climate change information has been extracted from RCP 8.5 Climate Change Scenario for IPCC AR5, then estimated the design rainfall for various durations at return periods. Finally, the design flood estimated through the HEC-HMS Model which is being widely used in the practices, estimated the effect of climate change on the Design Flood of Mihochen basin. The results suggested that the Design Flood increase by climate change. Due to this, the Flood risk of Mihochen basin can be identified to increase comparing the present status.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.238-238
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• 2015

There are demands for water environmental analysis of discharge processes in paddy fields, however, it is not fully understood in nutrients discharge process for watershed modeling. As hydrological processes both surface and ground water and agricultural water managements are so complex in paddy fields, the development of lowland paddy fields watershed model is more difficult than upland watershed model. In this research, the improvement of SWAT (Soil and Water Assessment Tool) model for a paddy watershed was conducted. First, modification of surface inundated process was developed in improved pot hole option. Those modification was evaluated by monitoring data. Second, the monitoring data in river and drainage channel in lowland paddy fields from 2012 to 2014 were analyzed to understand discharge characteristics. As a case study, Imbanuma basin, Japan, was chosen as typical land and water use in Asian countries. In this basin, lowland paddy fields are irrigated from river water using small pumps that were located in distribution within the watershed. Daily hydrological fluctuation was too complex to estimate. Then, to understand surface and ground water discharge characteristics in irrigation (Apr-Aug) and non-irrigation (Sep-Mar) period, the water and material balance analysis was conducted. The analysis was composed two parts, watershed and river channel blocks. As results of model simulation, output was satisfactory in NSE, but uncertainty was large. It would be coming from discharge process in return water. The river water and ground water in paddy fields were exchanged each other in 5.7% and 10.8% to river discharge in irrigation and non-irrigation periods, respectively. Through this exchange, nutrient loads were exchanged between river and paddy fields components. It suggested that discharge from paddy fields was not only responded to rainfall but dynamically related with river water table. In general, hydrological models is assumed that a discharge process is one way from watershed to river. However, in lowland paddy fields, discharge process is dynamically changed. This function of paddy fields showed that flood was mitigated and temporally held as storage in ground water. Then, it showed that water quality was changed in mitigated function in the water exchange process in lowland paddy fields. In future, it was expected that hydrological models for lowland paddy fields would be developed with this mitigation function.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.417-428
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• 2021

The combustion characteristics of anthracite, which follow a complex process with low reactivity, must be considered through the dynamic behavior of circulating fluidized bed (CFB) boilers. In this study, computational fluid dynamics (CFD) simulation was performed to analyze the combustion characteristics of anthracite in a pilot scale 0.1 MW_th Oxy-fuel circulating fluidized bed (Oxy-CFB) boiler. The 0.1MW_th Oxy-CFB boiler is composed of combustor (0.15 m l.D., 10 m High), cyclone, return leg, and so on. To perform CFD analysis, a 3D simulation model reactor was designed and used. The anthracite used in the experiment has an average particle size of 1,070 ㎛ and a density of 2,326 kg/m³. The flow pattern of gas-solids inside the reactor according to the change of combustion environment from air combustion to oxygen combustion was investigated. At this time, it was found that the temperature distribution in air combustion and oxygen combustion showed a similar pattern, but the pressure distribution was lower in oxygen combustion. addition, since it has a higher CO₂ concentration in oxygen combustion than in air combustion, it can be expected that carbon dioxide capture will take place actively. As a result, it was confirmed that this study can contribute to the optimized design and operation of a circulating fluidized bed reactor using anthracite.