• Journal of Korea Spatial Information System Society
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• v.8 no.3
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• pp.105-115
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• 2006

A sensor network which uses DCS(Data-Centric Storage) stores the same data into the same sensor node. Thus it has a hot spot problem when the sensor network grows and the same data arise frequently. In the past researches of the sensor network using DCS, the hot spot problem caused by growing the sensor network was ignored because they only concentrated on managing stored sensor data efficiently. In this paper, we proposed a non-equal region split method that supports efficient scalability on storing multi-dimensional sensor data. This method can reduce the storing cost, as the sensor network is growing, by dividing whole space into regions which have the same number of sensor nodes according to the distribution of sensor nodes, and storing and managing sensor data within each region. Moreover, this method can distribute the energy consumption of sensor nodes by increasing the number of regions according to the size of the sensor network, the number of sensor nodes within the sensor network, and the quantity of sensor data. Therefore it can help to increase the life time and the scalability of the sensor network.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1423-1428
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• 2013

In this study, a heat dissipation measurement system is developed to analyze a 1.2-kW BLDC motor. It is important to check the temperature of the motor because an increase in temperature causes problems in the motor insulations, which in turn influences the motor life. A generator for a vehicle is installed to set up a load. We changed the load from 165 to 495 W. While the rpm varies from 2000 to 4000 under various load conditions, the changes in temperature were measured for the operating period by using a thermocouple. The results of experiments conducted under natural convection conditions suggest that the temperature was not stationary with the rpm, load, and coil of the motor and it kept increasing over $120^{\circ}C$. However, under forced convection conditions, the temperature stationarily reached $84^{\circ}C$ after 4000 s. The difference between the maximum and the minimum temperatures was $10-26^{\circ}C$ with an increase in the rpm and load. The orders of high temperature were as follows: motor coil (Ch#1), side of motor surface (Ch#5), inside of motor cap (Ch#2), upper side of motor surface (Ch#4), and inner wall of the motor (Ch#3).

• Publications of The Korean Astronomical Society
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• v.17 no.1
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• pp.23-40
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• 2002

The spatial distribution of meteoroids or cometary debris along the orbit of the Earth is investigated by analyzing the meteoric records in the Chronicle of the Koryo dynasty (918-1392) which is called Koryosa. Sporadic meteors in this period show the seasonal variation in number, which is similar to the current meteors. We also found that there are a few spikes showing large accumulation of records around the same dates. We regard these spikes as meteor showers in the Koryo period. We compared the dates of meteor showers with those compiled from the historical records around the world including Korea, Japan, China, Arab, and European countries. We discovered three prominent showers and four weak showers. The prominent ones are the Leonids, the Perseids, and the Aquarids and the Orionids pair. The last pair is the remnants of Halley's comet. The astronomical records written in the history book of the Koryo dynasty are turned out to be accurate and written in a steady manner. We can also see that those records can be useful to contribute the development of modern astronomy and astrophysics.

• Korean journal of applied entomology
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• v.28 no.2
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• pp.61-68
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• 1989

To investigate the possibility of the BPH control by systematic application of insecticides, biological effects of buprofezin and isoprothiolane upon the BPH population was evaluated in the laboratory and pot. Both chemicals did not affect the developmental period of the nymphal stage with the applied dosages. When the buprofezin treated instar nymph was developed to the adult, adult's longevity was fairly reduced and such an effect of buprofezin was greater upon the younger instar nymphs. Residual effect of buprofezin was about 30 days in the pot. And it could suppress the BPH population when the younger instar nymphs were dominant age group in the population at the time of treatment. Isoprothiolane was also more effective for the suppression of the BPH population when the younger instar nymphs were dominant at the time of treatment. And it was expected that by buprofezin treatment in July the control effect of isoprothiolane against the BPH population could be maximized when it was treated to control the rice neck blast in late July or early August, because buprofezin could induce the biased population age distribution in which younger instar nymphs were main group at the time of isoprothiolane treatment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.1
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• pp.19-35
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• 2014

A parametric sensitivity to the annual exposure dose rate to the farming exposure group has been probabilistically carried out for three principal elements associated with the nuclide transport behavior in the near-field of the pyroprocessed waste repository system. Credit time for both metal and ceramic containers, annual nuclide release rete, and the degree of loss of bentonite buffer around the container are selected as the elements and investigated for important nuclides. All the elements are shown to be sensitive to the results. Methodology studied through this study and the results are expected to make a good feedback to the repository design. As a follow-up study, separated in Part 2, the A-KRS will be deterministically assessed and then compared among each other with the normal, the worst, and the best case scenarios associated with their extreme values these elements could have.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.191-202
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• 1985

As the result of a significant improvement in the economic situation and development of scientific techniques in Korea during the last 20 years, the life expectancy of the Korean people has lengthened considerably and as a result the number of old aged people has markedly increased. Such an increase of the number of aged people brought about many problems. Authors would like to take a medical look at the "Problem of old aged people" presently facing us in Korea. Currently the number of people over 65 has increased rapidly and is 1,620,000, 4% of total population. But it is still much lower than 8.9% in Japan, 10.7% in U.S.A., and 14.9% in the United Kingdom. Over 25% of these aged people were found to have at least more than one disease which requires medical care. Diseases occur in the circulatory system, 30.9%, respiratory system, 17.1%, digestive system 8.6%, mental disorders, 8.4%, malignant neoplasms, 7.0%. About 51% of the aged over 65 are under medical security benefit, mostly with partial coverage plan. Their clinic visit rate was very low (2.0% in 1981), which might be due to financial reasons. Since diseases affecting the aged progress chronically, early detection and long term care are utter most important. However there is almost no special facility, long term care center or geriatric specialist. For proper management of medical problems in the growing population of the Korean eldery expansion of medical security coverage, greater number of specialized facilities, education of geriatric special manpower and efficient operating system should be established.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.21-29
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• 1998

The rare-earth orthoborate family, RM3(BO3)4 is known to be the most promising material for the microlaser host. To grow LaSc3(BO3)4 single crystal, the phase relation of the system LaBO3-ScBO3 was investigated by DTA method. LaSc(BO3)4 was the unique intermediate compound in the binary system the peritectic reaction point of which was 1495 ±2℃. Owing to the peritectic behavior of the compound, the crystal growth of the rare-earth Sc-borate was carried out by pulling from the melt-soultion of La1+xSc3-x(BO3)4. The optimal conditions for the growth of LaSc3(BO3)4 were determined by traditional CZ method : pulling speed 0.7mm/hr, rotation speed 7-10 rpm under reduction condition. Pt and Ir crucibles could be used for about 8-10 times of growth. The effect of thermal configurations on the temperature distribution was investigated. A special two-coordinate manipulator was made for the precise movement of thermocouples from the melt to the top of the furnace for several thermal configurations. The radial gradient on the melt surface depends strongly on the construction of the afterheater. On the other hand, the axial gradient was mainly propotional to both the opening degree of baffle plate and the mutual positions of crucible and heater.

• Journal of Radiation Protection and Research
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• v.28 no.2
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• pp.109-116
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• 2003

Based on the necessity to evaluate the activation products inventory during decommissioning lot domestic nuclear power plants, a preliminary estimation of the activation products inventory for Kori unit 1, which is getting close to the end of lifetime, was carried out with ANISN and ORIGEN2 code. In order to calculate neutron nux using ANISN code, the reactor was divided into 9 zones from core to bioshield concrete for radial direction. Also :he cross-section of main nuclides were calibrated with neutron flux in the reactor pressure vessel(RPV) region. The results showed that 95 % of tile total radioactivity in RPV from reactor shutdown to 10 years came from the nuclides of $^{55}Fe,\;^{59}Ni,\;^{63}Ni\;and\;^{60}Co$. And the total radioactivity with cooling of more than 50 years after decommissioning was no more than 0.2 % of at the time of shutdown. Considering the weight of RPV is 210 tons, the total radioactivity of RPV reached to $5.25{\times}10^{6}GBq$ at shutdown time. As compared with the total radioactivity of bioshield concrete at reactor shutdown time, the radioactivity after tooling more than 10 years was below 1 %.

• Proceedings of the Korea Technology Innovation Society Conference
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• 1999.11c
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• pp.521-543
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• 1999

최근 과학기술 혁신 활동의 세계화 현상과 함께 한국의 연구개발 활동도 점차 세계화되고 있다. 그러나 한국의 연구개발 활동의 세계화 현상 및 바람직한 방향에 관한 연구는 별로 없다. 세계화에 따라 국내 연구개발 자원의 유출현상도 발생하지만, 해외 연구개발 자원을 활용할 수 있는 기회도 증가한다. 본 논문에서는 연구개발 활동의 세계화에 관한 흐름 및 개념을 제시하고, 국내 외국인 연구 인력의 활용 현황 및 활용성과 영향 요인을 조사하여 외국인 연구인력 활용 방안을 탐색하였다. 외국과의 연구자 교류는 1996년 현재 유입이 약 4,300명, 유출이 약 16,000명으로 유출이 크지만, 많은 규모는 아니다. 국내 활용 외국인 연구자의 경우 1998년에는 주춤하였지만 꾸준한 증가 추세에 있다. 외국인은 비선진국, 특히 러시아 및 중국의 연구자들을 많이 활용되고 있다. 활용 분야는, 기초, 응용, 개발 연구별로 고루 분포되어 있으며, 상대적으로 정보 전자통신, 에너지 및 자원 분야에서 활용을 많이 하고 있었다. 외국인 연구자들이 참가한 프로젝트는 한국에서 기술도입기나 기술성장기에 해당하는 프로젝트들이 거의 대부분이었다. 월평균 급여는 1,500,000원부터 2,300,000원 정도의 범위에 속했다. 활용 기간을 보면 50%이상이 1년 미만이었으며 2년 이상은 약 10%정도 수준으로 단기간 활용을 위주로 하고 있는 편이다. 외국인 연구자 활용의 이유로써는 외국인 연구자가 가지고 있는 과학기술 지식을 흡수하거나 공동으로 신기술 지식을 개발하려는 목적 등이 지원제도 이용 차원이나, 해외 연구 네트워크 구축, 단순한 연구인력 충원 차원 등의 목적보다 많은 것으로 나타났다. 이는 기초과학 수준이 높은 북방권 국가들의 과학자들이 주로 활용되고 있다는 점에서도 잘 알 수 있으며 우리의 과학기술 약점을 보완하는 원천으로써 외국인 연구 인력이 대안이 되고 있음을 시사한다. 본 연구에서는 한국 연구 조직에서 일하는 외국인 연구자들의 동기 및 성과에 영향을 미치는 많은 요인들을 확인할 수 있었다. 상관관계, 분산분석, 회귀분석 등을 통해 활용 성과에 미치는 영향 요인들을 도출하였다. 설문 분석을 통하여 동기 및 성과 사이에는 강한 상관관계가 존재하는 것을 확인할 수 있었으며 이는 전통적인 동기 이론들과 부합한다. 대부분의 변수가 동기 및 성과에 동시에 영향을 미치는 것으로 조사되었으며 그중에서도 조직 협력 문화, 외국인 연구자의 의사소통 및 협력성, 외국인 연구자의 연구 능력 관련 변수들 및 연구 프로젝트의 기술수명주기, 외국인 연구자의 기존 기술지식의 흡수 등이 가장 중요한 변수로 나타났다. 이는 우리가 주로 중국 및 러시아 과학자들을 활용하여 상업화하는 외국인 연구인력 활용 패턴과도 일치하는 결과이다. 즉 우호적인 조직문화를 가지고 있는 연구 조직에서, 이미 과학기술 지식을 많이 가지고 있고 연구 능력도 높은 외국인 과학기술자를, 한국에서 기술이 태동 또는 성장하고 있는 연구 분야에서 활용하는 것이 가장 성과가 좋다는 사실을 확인시켜 주고 있다. 국내에서 최초로 수행된 본 연구는 외국인 연구 인력의 활용 성과가 매우 높으며, 우리의 과학기술혁신시스템을 보완하는 유효한 수단으로써 외국인 연구 인력이 중요한 대안이 될 수 있음을 발견하였다. 외국인 연구 인력을 잘 활용하기 위하여 문제점 및 개선방안을 활용 환경, 연구 인력이 중요한 대안이 될 수 있음을 발견하였다. 외국인 연구 인력을 잘 활용하기 위하여 문제점 및 개선 방안을 활용 환경, 연구 인력관리. 인력 교류사업, 외국인 과학자 지원 창구 등으로 나누어서 정리하였다. 연구시설, 주거시설 등의 하드웨어적 환경에 대한 개선도 중요하지만 연구 인력의 관리 능력 제고, 인력 교류 사업의 개선, 정보 제공 등 소프트웨어적인 활용 능력을 제고하는데 정책적인 관심을 기울이는 것이 중요하다고 판단된다.

• Economic and Environmental Geology
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• v.38 no.1
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• pp.91-99
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur mineral pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this paper the generation characteristics and the prediction of ARD of various cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Fourteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.