• KDI Journal of Economic Policy
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• v.36 no.4
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• pp.135-169
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• 2014

This study empirically analyzes changes in production patterns of farmers by agricultural disaster insurance. The aim of this project is to achieve stability of farm management by paying insurance in case of a natural disaster. However, it causes farmers to change production patterns in the direction of increasing production, and leads the crop price to drop. This can be explained by producers' risk reduction through the disaster insurance. The empirical analysis is based on IV approach with using two stage least squares method. The first stage estimates by difference-in-differences methodology indicate that the production of insurable crops increases more about 80,000ton on average than that of non-insurable crops. In addition, to solve the endogeneity problem caused by general supply and demand model, I use the first stage estimates and find that the price index of the crops drops about 2.3% according to the production increase by 10,000ton. The credibility of these results is also attained by various robustness checks. These findings suggest that it is necessary for government to analyze the whole economy which consists of producer and consumer welfare when it determines the policy. Besides, it implies that it is essential to develop a new market to cope with the unintended effect.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.29-41
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• 2014

The Korean government has purchased land properties alongside any significant water bodies before setting up the buffers to secure water qualities. Since the annual budgets are limited, however, there has always been the issue of which land parcels ought to be given the priority. Therefore, this study aims to develop efficient mechanism for land acquisition priorities in stream corridors that would ultimately be vegetated for riparian buffer zones. The criteria of land acquisition priority were driven through literary review along with experts' advice. The relative weights of their value and priorities for each criterion were computed using the Analytical Hierarchy Process(AHP) method. Major findings of the study are as follows: 1. The decision-making structural model for land acquisition priority focuses mainly on the reduction of non-point source pollutants(NSPs). This fact is highly associated with natural and physical conditions and land use types of surrounding areas. The criteria were classified into two categories-NSPs runoff areas and potential NSPs runoff areas. 2. Land acquisition priority weights derived for NSPs runoff areas and potential NSPs runoff areas were 0.862 and 0.138, respectively. This implicates that much higher priority should be given to the land parcels with NSPs runoff areas. 3. Weights and priorities of sub-criteria suggested from this study include: proximity to the streams(0.460), land cover(0.189), soil permeability(0.117), topographical slope(0.096), proximity to the roads(0.058), land-use types(0.036), visibility to the streams(0.032), and the land price(0.012). This order of importance suggests, as one can expect, that it is better to purchase land parcels that are adjacent to the streams. 4. A standard scoring system including the criteria and weights for land acquisition priority was developed which would likely to allow expedited decision making and easy quantification for priority evaluation due to the utilization of measurable spatial data. Further studies focusing on both point and non-point pollutants and GIS-based spatial analysis and mapping of land acquisition priority are needed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.5 s.96
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• pp.482-487
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• 2005

In this paper, we propose the control method of output impedance of each cascode unit cell of distributed amplifier by connecting varactors in the gate-terminal of common gate. Compared to common source unit cell, cascode unit cell has many advantages such as high gain and high output impedance as well as negative resistance loading. But if the transistor model which is used in design is inaccurate and process parameter is changed, oscillation sometimes can occur at band edge in which the gain start to drop. Therefore, we need control circuit which can prevent oscillation, although the circuit has already fabricated, and varactor connected to gate-terminal of common gate of cascode gain cell can play that part. Measured result of fabricated distributed amplifier shows the capability of contol of gain characteristic by adjusting of value of varactors, this can guarantee the stability of the circuit. The gain is $8.92\pm0.82dB$ over 49 GHz, the group delay is $\pm9.3 psec$ over 41 GHz. All transistor which has $0.15{\mu}m$ gate length is GaAs based p-HEMT, and distributed amplifier is put together with 4 stages.

• Journal of Preventive Medicine and Public Health
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• v.2 no.1
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• pp.61-76
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• 1969

A review has been made of mortality trends in Korea from 1958 to 1967 analyzing the data by sex, age and cause of death. The crude death rates and age specific death rates were estimated by the model of N. Keyfitz life table which had been developed by the data of the 1960's national census. The cause specific death rates shown in this article are based on the following: all deaths occurring in the death-registration are expressed as a numberator, while the denominator was estimated from the regular national census data by interpolation method. It is estimated that only an average of about 40% of deaths which occurred during a year were registered during 1958 to 1967. The validity and the reliability of the diagnosis of causes of death seem to be extremely poor in this country. Therefore the cause specific death rates in this article are aimed to reveal trends of causes of registered death ana not for the actual level of death rates. For 10 years very interesing mortality trends were observed : 1. The trend in the crude death rates was downward slowly. 2. The estimated death rate for the infant in 1960 was still high up to 100 per 1,000. 3. The rates for mortality attributed to such infectious diseases as pneumonia, bronchitis, gastroenteritis and measles decreased an average 40-60%. 4. The death rates for over-all tuberculosis decreased only 9.8%. 90% of the decrease was contributed by those in the less-than-15 year age group. 5. The death rates for chronic diseases, such as vascular diseases affecting the central nervous system, malignant neoplasm, major heart diseases and all accidents rose about 40-60%. 6. The rank order of the 10 leading causes of death showed large changes over the years, except for pneumonia and tuberculosis which occupyed 1st and 2nd places respectively. Vascular diseases affecting the central nervous system moved from 5th to 3rd place and malignant neoplasm from 6th to 4th place, The major heart diseases moved from 10th to 6th place and all accidents from 10th to 7th place. On tile other hand, gastroenteritis moved from 3rd to 5th place and influenja from 4th to 8th place.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.9
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• pp.25-37
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• 2007

The existing route re-establishment methods which intend to extend the lifetime of the network attempt to find new routes in order not to overly consume energy of certain nodes. These methods outperform other routing algorithms in the network lifetime extension aspect because they try to consume energy evenly for the entire network. However, these algorithms involve heavy signaling overheads because they find new routes based on the flooding method and route re-acquisition occurs often. Because of the overhead they often can not achieve the level of performance they intend to. In this paper, we propose a new route re-acquisition algorithm ARROW which takes into account the cost involved in the packet transmission and the route re-acquisition. Since the proposed algorithm considers future route re-acquisition costs when it first finds the route, it spends less energy to transmit given amount of data while evenly consuming the energy as much as possible. Using 2-dimensional Markov Chain model, we compare the performance of the proposed algorithm and that of other algorithms. Analysis results show that the proposed algorithm outperforms the existing route re-acquisition methods in the signaling overhead and network lifetime aspects.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1649-1654
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• 1991

In 1995 the VSOP satellite, which is called MUSES-B in Japan, will be launched under the VLBI Space Observatory Programme(VSOP) promoted by ISAS(Institute of Space and Astronautical Science) of Japan. We are now developing the GPS Receiver(GPSR) and On-board Orbit Determination System. This paper describes the GPS(Global Positioning System), VSOP, GPSR(GPS Receiver system) configuration and the results of the GPS system analysis. The GPSR consists of three GPS antennas and 5 channel receiver package. In the receiver package, there are two 16 bits microprocessing units. The power consumption is 25 Watts in average and the weight is 8.5 kg. Three GPS antennas on board enable GPSR to receive GPS signals from any NAVSTARs(GPS satellites) which are visible. NAVSATR's visibility is described as follows. The VSOP satellite flies from 1, 000 km to 20, 000 km in height on the elliptical orbit around the earth. On the other hand, the orbit of NAVSTARs are nearly circular and about 20, 000 km in height. GPSR can't receive the GPS signals near the apogee, because NAVSTARs transmit the GPS signals through the NAVSTAR's narrow beam antennas directed toward the earth. However near the perigee, GPSR can receive from 12 to 15 GPS signals. More than 4 GPS signals can be received for 40 minutes, which are related to GDOP(Geometric Dillusion Of Precision of selected NAVSTARs). Because there are a lot of visible NAVSTARs, GDOP is small near the perigee. This is a favorqble condition for GPSR. Orbit determination system onboard VSOP satellite consists of a Kalman filter and a precise orbit propagator. Near the perigee, the Kalman filter can eliminate the orbit propagation error using the observed data by GPSR. Except a perigee, precise onboard orbit propagator propagates the orbit, taking into account accelerations such as gravities of the earth, the sun, the moon, and other acceleration caused by the solar pressure. But there remain some amount of calculation and integration errors. When VSOP satellite returns to the perigee, the Kalman filter eliminates the error of the orbit determined by the propagator. After the error is eliminated, VSOP satellite flies out towards an apogee again. The analysis of the orbit determination is performed by the covariance analysis method. Number of the states of the onboard filter is 8. As for a true model, we assume that it is based on the actual error dynamics that include the Selective Availability of GPS called 'SA', having 17 states. Analytical results for position and velocity are tabulated and illustrated, in the sequel. These show that the position and the velocity error are about 40 m and 0.008 m/sec at the perigee, and are about 110 m and 0.012 m/sec at the apogee, respectively.

• Journal of Gastric Cancer
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• v.13 no.4
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• pp.214-225
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• 2013

Purpose: Peritoneal lavage cytology is part of the routine staging workup for patients with advanced gastric cancer. However, no quality assurance study has been conducted to show variations or biases in peritoneal lavage cytology results. The aim of this study was to demonstrate a test execution variation in peritoneal lavage cytology between investigating surgeons. Materials and Methods: A prospective cohort study was designed for determination of the positive rate of peritoneal lavage cytology using a liquid-based preparation method in patients with potentially curable advanced gastric cancer (cT2~4/N0~2/M0). One hundred thirty patients were enrolled and underwent laparotomy, peritoneal lavage cytology, and standard gastrectomy, which were performed by 3 investigating surgeons. Data were analyzed using the chi-square test and a logistic regression model. Results: The overall positive peritoneal cytology rate was 10.0%. Subgroup positive rates were 5.3% in pT1 cancer, 2.0% in pT2/3 cancer, 11.1% in pT4a cancer, and 71.4% in pT4b cancer. In univariate analysis, positive peritoneal cytology showed significant correlation with pT stage, lymphatic invasion, vascular invasion, ascites, and the investigating surgeon. We found the positive rate to be 2.1% for surgeon A, 10.2% for surgeon B, and 20.6% for surgeon C (P=0.024). Multivariate analysis identified pT stage, ascites, and the investigating surgeon to be significant risk factors for positive peritoneal cytology. Conclusions: The peritoneal lavage cytology results were significantly affected by the investigating surgeon, providing strong evidence of test execution variation that could be related to poor diagnostic accuracy and stage migration in patients with advanced gastric cancer.

• Journal of The Korean Association For Science Education
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• v.33 no.1
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• pp.161-180
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• 2013

The purpose of this paper is to introduce the current studies and research methods about Learning Progressions disseminated to several countries including the U.S. since 2006. It also provides a methodological base to investigate learning progressions in science by introducing a case study of learning progression conducted in Korea. For this study, we described several features of current studies on learning progressions in the U.S., and reported the common ways and sequences employed in examining learning progressions especially with respect to assessment for learning. Learning progressions are descriptions of developmental pathways of learning a topic, in which science knowledge is used in students' engaging in science practices. Each learning progression consists of upper anchor, lower anchor, and intermediate steps that connect both anchors. In investigating a learning progression, researchers usually utilize Wilson's four building blocks of assessment system based on the assessment triangle. This kind of method was also applied in investigating the learning progression for water cycle in this study. We discussed implication and consideration for the future research on learning progressions in science in Korea.

• Journal of The Korean Association For Science Education
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• v.38 no.3
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• pp.343-354
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• 2018

In this study, the first experience of the whole research process of a novice scientist (student A) who participated in the Undergraduate Research Program (URP) was analyzed. The data were collected through observation, interviews, and document analysis with the cultural historical activity theory being used as a theoretical lens. At the beginning of novice's research, the mentor guided him in setting a research goal and provided mediating artifacts. Student A formed a research team based on the vertical relationship without a shared mental model. Two major contradictions occurred and they were the sources of changes of student A's activity system. The first contradiction was between the mentor's educational philosophy and the mentee's educational needs, which was resolved in a way that student A asked and used the mentor's network to obtain his needs about task-specific details. The second contradiction arose because the team members wanted horizontal relationship while student A wanted to stick to the vertical relationship. After student A accepted the opinions of the team members, they cooperatively changed the division of labor in the activity system. Student A decided to become a scientist and not a physics teacher, even if his major is physics education after finishing his URP research process. His URP experience also created and expanded his network in the academic field, and his negative attitude toward collaboration changed positively. Through the analysis of the structure and changes in the activity system of URP research, implications for instructional method and support system of the apprenticeship can be obtained.

• Journal of Venture Innovation
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• v.1 no.1
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• pp.181-195
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• 2018

The purpose of this study is to investigate the effect of service quality of a theater on the customer experience value and performance satisfaction and to test causality between variables. For this purpose, Study model was created from the previous studies and performed a survey with the customer who visited Performance Theater. In this study, employee kindness, facility excellence, convenience, and facilities were set as independent variables, and performance satisfaction was selected as a dependent variable. The cultural value and economic value of customer experience were examined as Moderating variables between two variables. Based on the results of this study, It was found that employee's kindness, facility excellence, and convenience have a significant effect on performance satisfaction in performing arts facilities. convenience, there was perfect mediated effect of customer experience between service quality of a theater and performance satisfaction centered on cultural value and economic value. The employee's kindness variable was examined as a perfect mediation of cultural value, and economic value as a sectoral mediation. The excellence variables of the facilities appeared as partial mediations in cultural values and as complete mediations in economic values. In the case of the auxiliary facilities, the significance test failed. According to the results of the research, it was confirmed that convenience service for customers is the most important variable. This result suggests that the service quality of a theater should be basically maintained in terms of the kindness of the facility and staff, and that the customer is more satisfied with the performance than the audience convenience service provided from the Theater. The venue suggests that customer service and reception, purchase of tickets, refund method, and staff training should be thoroughly done so that audiences can make the Theater.