• Bulletin of the Korean Mathematical Society
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• v.56 no.2
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• pp.439-450
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• 2019

Let R be a ring with unity. Given modules $M_R$ and $_RN$, $M_R$ is said to be absolutely $_RN$-pure if $M{\otimes}N{\rightarrow}L{\otimes}N$ is a monomorphism for every extension $L_R$ of $M_R$. For a module $M_R$, the subpurity domain of $M_R$ is defined to be the collection of all modules $_RN$ such that $M_R$ is absolutely $_RN$-pure. Clearly $M_R$ is absolutely $_RF$-pure for every flat module $_RF$, and that $M_R$ is FP-injective if the subpurity domain of M is the entire class of left modules. As an opposite of FP-injective modules, $M_R$ is said to be a test for flatness by subpurity (or t.f.b.s. for short) if its subpurity domain is as small as possible, namely, consisting of exactly the flat left modules. Every ring has a right t.f.b.s. module. $R_R$ is t.f.b.s. and every finitely generated right ideal is finitely presented if and only if R is right semihereditary. A domain R is $Pr{\ddot{u}}fer$ if and only if R is t.f.b.s. The rings whose simple right modules are t.f.b.s. or injective are completely characterized. Some necessary conditions for the rings whose right modules are t.f.b.s. or injective are obtained.

• Journal of radiological science and technology
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• v.46 no.2
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• pp.141-149
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• 2023

The Korea Institute of Radiological and Medical Sciences plans to produce ²²⁵Ac, a therapeutic radio-pharmaceutical for precision oncology, such as prostate cancer. Radon, a radioactive gas, is generated by radium, the target material for producing ²²⁵Ac. The radon concentration is expected to be about 2000 Bq·m^-3. High-concentration radon-generating facilities must meet radioactive isotope emission standards by lowering the radon concentration. However, most existing studies concerning radon removal using activated carbon filters measured radon levels at concentrations lower than 1000 Bq·m^-3. This study measured ²²²Rn removal of coconut-based activated carbon filter under a high radon concentration of about 2000 Bq·m^-3. The ²²²Rn removal efficiency of activated carbon impregnated with triethylenediamine was also measured. As a result, the ²²²Rn removal amount of the activated carbon filter showed sufficient removal efficiency in a ²²²Rn concentration environment of about 2000 Bq·m^-3. In addition, despite an expectation of low radon reduction efficiency of Triethylenediamine-impregnated activated carbon, it was difficult to confirm a significant difference in the results. Therefore, it is considered that activated carbon can be used as a radioisotope exhaust filter regardless of whether or not Triethylenediamine is impregnated. The results of this study are expected to be used as primary data when building an air purification system for radiation safety management in facilities with radon concentrations of about 2000 Bq·m^-3.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.207-216
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• 2000

Continuous measurements of radon progeny concentrations in the open atmosphere and measurements of meteorological parameters were performed in Tajeon, using a continuous gross alpha/beta aerosol monitor and a weather measuring equipment between July 1999 and July 2000. These data were analyzed for half-hourly, daily, and seasonal variations. The distribution of daily averaged equilibrium equivalent radon concentration$(EEC_{Rn})$ had an arithmetic mean value of $11.3{\pm}5.86Bqm^{-3}$ with the coefficient of variation of about 50% and the geometric mean was $10.3Bqm^{-3}$. The $EEC_{Rn}$ varies between 0.83 and $43.3Bqm^{-3}$, depending on time of day and weather conditions. Half-hourly averaged data indicated a diurnal pattern with the outdoor $EEC_{Rn}$ reaching a maximum at sunrise and a minimum at sunset. The pattern of the seasonal variation of the $EEC_{Rn}$ in Taejon had a tendency of minimum concentration occurring in the summer(July) and maximum concentration occurring in the late autumn(November). But the seasonal variation of the $EEC_{Rn}$ is expect to vary greatly from place to place. The outdoor $EEC_{Rn}$ was highly dependent on the local climate features. Particularly the $EEC_{Rn}$an rapidly drops less than $5Bqm^{-3}$ in case of blowing heavily higher than wind speed of $6msec^{-1}$, reversely the days with more than $30Bqm^{-3}$ were at a calm weather condition with the wind speed of lower than $1msec^{-1}$.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.225-228
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• 2011

핸드폰에 의한 모바일 콘텐츠의 사용량이 날로 증가하고 있으며 이러한 추세에 맞추어 다양한 콘텐츠들이 다양한 플렛폼에서 생산되고 있다. 모바일 플랫폼에서 사용 가능한 콘텐츠 생산성은 플랫폼의 특수성으로 인해 생산 속도가 느리고 인력 투입이 많은 것이 문제점으로 지적되고 있다. 또한 무선 플랫폼에서 사용 가능한 콘텐츠 제작시 다양한 하드웨어 플랫폼으로 인한 액정 크기의 다양성과 사용 가능한 콘텐츠 개발 언어의 다양성으로 인한 문제점도 많은 것으로 알려져 있다. 본 연구에서는 이러한 생산성 저하의 원인으로 대표되는 문제점들과 다양한 하드웨어 플랫폼으로 인해 발생하는 문제점들을 해결하기 위한 모바일 콘텐츠를 통합 제작하고 테스트하는 PC용 소프트웨어를 개발하였다. xHTML 언어로 제작된 모바일 콘텐츠를 다양한 언어로 변환하기 위하여 패턴매칭 알고리즘을 사용한 변환 모듈을 개발하였다. 또한, 변환된 콘텐츠들을 각 플랫폼별로 테스팅 하기 위하여 개발자의 직접적 개입이 없이 모든 콘텐츠를 자동으로 검사하고 결과를 리포트 생성하는 자동 테스트 부분과 개발자의 육안으로 확인하고 테스트하여 결과 리포트를 생성하는 수동 테스트 부분으로 나누어진 소프트웨어 엔진을 개발하였다. 이상의 변환엔진을 사용하여 xHTML로 제작한 원본 콘텐츠는 다양한 플랫폼에서 이용 가능한 콘텐츠로 생산이 용이해 졌으며, 두 테스트 엔진을 사용하여 기본적인 콘텐츠 오류들을 쉽게 찾아내고 수정할 수 있는 개발 환경을 구축하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.12
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• pp.749-755
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• 2003

Digital signal processing hardware based in RNS is currently considered as an important method for high speed and low cost hardware realization. This research designs and implements the method for conversion from a specific residue number system with moduli of the from $(2^k-1, 2^k, 2^k+1)$ to a weighted number system. Then, it simulates the implementation using a overlapped multiple-bit scanning method in the process of CRT conversion. In conclusion, the simulation shows that the CRT method which is adopted in this research, performs arithmetic operations faster than the traditional approaches, due to advantages of parallel processing and carry-free arithmetic operation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.308-311
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• 2005

[ $^{222}Rn\;and\;^{226}Ra$ ] in groundwater were determined simultaneously using a gamma-spectroscopy. A nitrogen flushing equipment has been used for elimination and stabilization of high and unstable background activity due to the radon and its progenies in counting shield and room. The aim of present work was to control the background activity for simultaneous measurement of radium$(^{226}Ra)$ and radon$(^{222}Rn)$ in groundwater using a gamma-spectrometry. Background activity was about 1.0dps and the standard deviation was about 50%, The background activity could be minimized using nitrogen flushing equipment in the range of 0.1 to 0.5 and the RSD was about 5% at the experimental condition. The detection limit of $^{222}Rn\;and\;^{226}Ra$ in groundwater was 0.5dps/L in the background control method. In most groundwater used in the work, radon activity was more than the detection limit. However, radium activity in some groundwater was less than the detection limit. If the low level radium in groundwater must be measured, preconcentration process such as concentration should be performed before measuring the groundwater.

• Journal of Integrative Natural Science
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• v.12 no.2
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• pp.58-68
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• 2019

Critical thinking is essential to implementing the nursing process requiring timely decision making. The study examined the effects of a critical thinking course for nurses in the RN-BSN program. The study used a pre- and post-test design with a control group. The experimental group was a convenience sample of 24 working nurses attending a health college. The control group was 24 fellow nurses. The nursing process-based critical thinking course was provided to the experimental group two and half hours a week for 8 weeks. Teaching methods included lectures followed by a summary and quiz, brainstorming and action learning, and lecturer feedback. A pamphlet about views of professional occupation was provided to the control group. The data were collected using self-report questionnaires and analyzed to examine differences in the test scores before and after the intervention. The scores of critical thinking disposition, problem-solving process, and clinical competence increased significantly in the experimental group but did not in the control group. The difference between the two groups was also statistically significant in critical thinking disposition, problem-solving process, and clinical competence. It is necessary that a robust educational program or training to enhance critical thinking ability of nurses are provided in clinical settings and that nurses keep going on thinking critically in their practice.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.257-261
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• 2015

Radon is produced after the Uranium-238 and thorium-232 undergone radioactive decay process is a colorless, odorless inert gas is stored in a basement or an enclosed space. Building materials are made by a rock or soil materials. Form of radon gas is introduced into the lungs through the respiratory tract and deposited in the lungs or bronchial Daughter nuclides radon causes lung cancer. In this study, To subject the Constructed Apartment in Gwangju Gwangsan-Gu, the position is closed window and opened window was measured using a measuring instrument for radon. The measured results indicate that the measurement was carried out in concentrations of radon gas measured at Newly Constructed Apartment is low than United states in the radon concentration in air public 4 pCi called radon gas baseline maximum allowable concentrations. The exposure caused by radon concentration of new construction apartment when on the measurement results is expected to be insignificant. However, when radon gas like this is that it accumulates in the body and lungs get damaged due to exposure, such as lung cancer often open the windows to reduce the radon concentration measurements, such as in radiation protection aspects to the ventilation to reduce exposure it is considered necessary.

• Journal of Korean Society on Water Environment
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• v.23 no.2
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• pp.201-205
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• 2007

This paper reports the amount of $^{222}Rn$ and $^{238}U$ in 18 sites of ground water and 30 sites of surface water. The instrument used to count $^{222}Rn$ activity was the liquid scintillation counter (LSC) which could resolute ${\alpha}$ and ${\beta}$ radiations. And $^{238}U$ was analyzed by the inductively coupled plasma (ICP). Radon and Uranium were not detected in raw and treated water which were sampled in a water treatment plant. However, radon ($^{222}Rn$) was high concentration in ground water from Jeon-la, Gang-won. So was uranium ($^{238}U$) in case of ground water from Gang-won, Choong-chung. Radon ($^{222}Rn$) activities were detected less than 15 pCi/L at 5 sampling points, 15~300 pCi/L at 7 sampling points, 300~4000 pCi/L at 6 sampling points. However, Radon ($^{222}Rn$) activities of all ground water samples were less than 4,000 pCi/L, which was bellow American Alternative Maximum Contamination Level (AMCL). Uranium ($^{238}U$) concentrations were less than $0.1{\mu}g/L$ at 5 sampling points, from $0.1{\mu}g/L$ to $20{\mu}g/L$ at 13 sampling points. Uranium was not detected in about 30% of the whole samples, but the concentration ranged from relatively low to high concentrations depending on the sampling point. The minimum detectable activity (MDA) of radon was 15 pCi/L. and the detection limit of uranium was $0.1{\mu}g/L$.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.95-111
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• 2012

This study investigated the relationship between the geochemical environment and the occurrence of natural radioactive materials (uranium and Rn-222) in borehole groundwater at an Icheon site. The drill core recovered from the study site consists mainly of biotite granite with basic dykes. The groundwater samples were collected at four different depths in the borehole using the double-packed system. The pH range of the groundwater was 6.5~8.6, and the chemical type was Ca-$HCO_3$. The ranges of uranium and Rn-222 concentrations in the groundwater were 8.81~1,101 ppb and 5,990~11,970 pCi/L, respectively, and concentrations varied greatly with depth and collection time. The ranges of uranium and thorium contents in drill core were 0.53~18.3 ppm and 6.66~17.5 ppm, respectively. Microscope observations and electron microprobe analyses revealed the presence of U and Th as substituted elements for major composition of monazite, ilmenite, and apatite within K-feldspar and biotite. Although the concentration of uranium and thorium in the drill core was not high, the groundwater contained a high level of natural radioactive materials. This finding indicates that physical factors, such as the degree of fracturing of an aquifer and the groundwater flow rate, have a greater influence on the dissolution of radioactive materials than does the geochemical condition of the groundwater and rock. The origin of Rn-222 can be determined indirectly, using an interrelationship diagram of noble gas isotopes ($^3He/^4He$ and $^4He/^{20}Ne$).