• Journal of Radiation Protection and Research
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• v.39 no.3
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• pp.127-133
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• 2014

North Korea's uranium enrichment facility is a matter of international concern. It is of particular alarming to South Korea with regard to the security and safety of the country. This situation requires continuous monitoring of the DPRK and emergency preparedness on the part of the ROK. To assess the detectability of an undeclared uranium enrichment plant in North Korea, uranium concentrations in the air at both a short and a long distance from the enrichment facility were estimated. $UF_6$ source terms were determined by using existing information on North Korean facility and data from the operation experience of enrichment plants from other countries. Using the calculated source terms, two atmospheric dispersion models (Gaussian Plume Model and HYSPLIT models) and meteorological data were used to estimate the uranium particle concentrations from the Yongbyon enrichment facility. A maximum uranium concentration and its location are dependent upon the meteorological conditions and the height of the UF6 release point. This study showed that the maximum uranium concentration around the enrichment facility was about $1.0{\times}10^{-7}g{\cdot}m^{-3}$. The location of the maximum concentration was within about 0.4 km of the facility. It has been assumed that the uranium sample of about a few micrograms (${\mu}g$) could be obtained; and that few micrograms of uranium can be easily measured with current measurement instruments. On the contrary, a uranium concentration at a distance of more than 100 kilometers from the enrichment facility was estimated to be about $1.0{\times}10^{-13}{\sim}1.0{\times}10^{-15}g{\cdot}m^{-3}$, which is less than back-ground level. Therefore, based on the results of our paper, an air sample taken within the vicinity of the Yongbyon enrichment facility could be used to determine as to whether or not North Korea is carrying out an undeclared nuclear program. However, the air samples taken at a longer distance of a few hundred kilometers would prove difficult in detecting a clandestine nuclear activities.

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.83-88
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• 2016

In this study, previously reported surplus solar energy-related study result and current status of fan coil unit (FCU) for cooling and heating installed in the current sites were briefly examined and then a method to determine the number of FCUs required to recover surplus solar energy was schematically proposed to provide basic data for researchers and technical engineers in this field. The maximum, mean, and minimum outside temperatures during the experiment period were about $28.2^{\circ}C$, $4.4^{\circ}C$, and $-11.5^{\circ}C$, respectively. The horizontal surface solar radiation level outside the greenhouse was in a range of $0.8-20.5MJ{\cdot}m^{-2}$ and mean and total solar radiation were $10.8MJ{\cdot}m^{-2}$ and $1,187.5MJ{\cdot}m^{-2}$. The mean temperature and relative humidity in the greenhouse during the daytime were in a range of 18.8-45.5 and 53.5-77.5%. The total surplus solar energy recovered from the greenhouse during the experiment period was approximately 6,613.4MJ, which could supplement about 6.7% of the total heating energy 98,600.2 MJ. In addition, the number of FCUs installed for heating varies case to case, although similar FCUs are used. Thus, it is necessary to study the installation height, orientation and installation distance as well as the appropriate number of FCUs from the efficient and economical viewpoints. The required numbers of FCUs for surplus solar energy recovery were 8.4-10.9units and 6.1-8.0units based on air mass and circular flow rate that passed through the FCUs. Considering calculation methods and the risks such as efficiency and use environments of FCUs, it was found that about nine units (one unit per $24m^3$ approximately) needed to be installed. The required number of FCUs for surplus solar energy recovery was around one unit per $24m^3$ approximately.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.295-300
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• 2018

Net radiation is the total amount of radiation energy used as a heat flux for the Earth's energy cycle, and net radiation from the surface is an important factor in areas such as hydrology, climate, meteorological studies and agriculture. It is very important to monitoring the net radiation through remote sensing to be able to understand the trend of heat island and urbanization phenomenon. However, net radiation estimation using only remote sensing data is generally causes difference in accuracy depending on cloud. Therefore, in this paper, we retrieved and monitored high resolution surface net radiation at 1 hour interval in Eunpyeong New Town where urbanization using Communication, Ocean and Meteorological Satellite (COMS), Landsat-8 satellite and Computational Fluid Dynamics (CFD) model data reflecting the difference in building height. We compared the observed and estimated net radiation at the flux tower. As a result, estimated net radiation was similar trend to the observed net radiation as a whole and it had the accuracy of RMSE $54.29Wm^{-2}$ and Bias $27.42Wm^{-2}$. In addition, the calculated net radiation showed well the meteorological conditions such as precipitation, and showed the characteristics of net radiation for the vegetation and artificial area in the spatial distribution.

• Journal of Animal Science and Technology
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• v.55 no.5
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• pp.373-380
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• 2013

The study aimed to develop prediction models of primal cut yield using body measurements of Hanwoo steers in Korea. The progeny of 874 steers at Hanwoo Improvement Main Center from 2008 to 2010 were recorded. Pearson's correlation coefficients for primal cuts and other traits were estimated. Primal cuts were adjusted for slaughter date and age using the SAS GLM procedure. Afterwards, a stepwise regression was performed on each primal cut by fitting body measurement traits. An independent covariable was selected at the highest coefficient of determination with the greater fitness model using Mallows's Cp statistic. Results showed that primal cuts were significantly influenced by slaughter date (P<0.01). The age at slaughter, however, was only significant for the top round (P<0.05). There was a moderate to high correlation between chest girth and tenderloin (0.54), loin (0.74), and rib (0.80). Most primal cut percentages were negatively related to BFT. Similar negative to low positive correlations were observed for primal cut percentage and body size traits. In addition, a correlation of 0.21 was observed between rib percentage and chest girth. The regression of body measurements on the adjusted primal cuts were significant for later traits. Regression estimates revealed that wither height, body length, rump length, hip bone width, and chest girth are important for primal cut weight and percentage determination. In particular, chest girth was always important for primal cut weight estimates.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.814-819
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• 2004

An investigation was carried out to study the effect of two housing systems on feed intake and nutrient utilization of sheep in a semi-arid region of India. Two types of housing managements were adopted. The first was a shed- 20'${\times}$10' structure with all the four sides of 6' chain link fencing with central height of 10'. The roof was covered with asbestos sheets, with mud floorings. The second was an open corral- 20'${\times}$10' open space with all the four sides covered with 6' chain link fencing. Thirty-four (32 ewes and 2 rams) sheep were grazed together on a 35 ha plot of native range. All the sheep were grazed as a flock from 08:00 to 17:00 h during the yearlong study. The flock was divided into two groups (16 ewes+1 ram) in the evening and housed according to two housing systems (Shed and Open Corral). Three digestion trials were conducted during three defined seasons of monsoon, winter and summer seasons to determine the effect of housing on nutrient intake and utilization. Blood samples were collected in three seasons for the estimation of hemoglobin and glucose. Dry and wet bulb temperatures were recorded at 06:00 A.M. and 09:00 P.M. using suitable thermometers both inside the shed and in the open corral and temperature humidity index (THI) was calculated. There was significant (p<0.05) difference in the THI between shed and open corral in all the seasons, indicating that the shed was always warmer compared to open corral. The daily dry matter intake (DMI, g/d) was 965, 615 and 982 in sheep housed under shed and 971, 625 and 1,001 in those housed in open corral during monsoon, winter and summer season, respectively. These differences were however non-significant (p>0.05). The digestibility of DM was 45.92, 45.13 and 50.30 in sheep housed under shed and 43.64, 45.02 and 55.02 in sheep housed in open corral during monsoon, winter and summer seasons, respectively. There was no significant (p>0.05) difference in the digestibility of nutrients in sheep maintained under shed and in open corral. Blood Hb concentration was 13.97, 14.13 and 13.15 in sheep housed under shed and 15.27, 13.63 and 14.82 in those kept in open corral, whereas blood glucose concentration was 59.67, 59.70 and 52.33 in sheep under shed and 61.00, 61.00 and 57.83 in open corral, during monsoon, winter and summer, respectively. There was also no significant effect of housing on the body weight changes, wool yield and survivability in ewes. Although housing had no significant effect on nutrient intake, their utilization and blood parameters, there was significant effect on the physiological responses and energy expenditure of sheep maintained under the two housing systems (Bhatta et al., 2004). It can be concluded from this study that the housing systems didn't have any significant effect on the nutrient intake and utilization of native breed like Malpura, which were well adapted to the hot semi-arid conditions of India. However, while deciding provisions for housing of different breeds of sheep (both crossbred and native) parameters like physiological responses, energy expenditure, health conditions and overall economics of the systems should be taken into consideration.

• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.1
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• pp.53-66
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• 1980

The research work is concerned with the analytical and experimental studies on the heat transfer phenomenon around the underground concrete digester used for biogas production Systems. A mathematical and computational method was developed to estimate heat losses from underground cylindrical concrete digester used for biogas production systems. To test its feasibility and to evaluate thermal parameters of materials related, the method was applied to six physical model digesters. The cylindrical concrete digester was taken as a physical model, to which the model,atical model of heat balance can be applied. The mathematical model was transformed by means of finite element method and used to analyze temperature distribution with respect to several boundary conditions and design parameters. The design parameters of experimental digesters were selected as; three different sizes 40cm by 80cm, 80cm by 160cm and l00cm by 200cm in diameter and height; two different levels of insulation materials-plain concrete and vermiculite mixing in concrete; and two different types of installation-underground and half-exposed. In order to carry out a particular aim of this study, the liquid within the digester was substituted by water, and its temperature was controlled in five levels-35。 C, 30。 C, 25。 C, 20。C and 15。C; and the ambient air temperature and ground temperature were checked out of the system under natural winter climate conditions. The following results were drawn from the study. 1.The analytical method, by which the estimated values of temperature distribution around a cylindrical digester were obtained, was able to be generally accepted from the comparison of the estimated values with the measured. However, the difference between the estimated and measured temperature had a trend to be considerably increased when the ambient temperature was relatively low. This was mainly related variations of input parameters including the thermal conductivity of soil, applied to the numerical analysis. Consequently, the improvement of these input data for the simulated operation of the numerical analysis is expected as an approach to obtain better refined estimation. 2.The difference between estimated and measured heat losses was shown to have the similar trend to that of temperature distribution discussed above. 3.It was found that a map of isothermal lines drawn from the estimated temperature distribution was very useful for a general observation of the direction and rate of heat transfer within the boundary. From this analysis, it was interpreted that most of heat losses is passed through the triangular section bounded within 45 degrees toward the wall at the bottom edge of the digesten Therefore, any effective insulation should be considered within this region. 4.It was verified by experiment that heat loss per unit volume of liquid was reduced as the size of the digester became larger For instance, at the liquid temperature of 35˚ C, the heat loss per unit volume from the 0. 1m$^3$ digester was 1, 050 Kcal/hr m$^3$, while at for 1. 57m$^3$ digester was 150 Kcal/hr m$^3$. 5.In the light of insulation, the vermiculite concrete was consistently shown to be superior to the plain concrete. At the liquid temperature ranging from 15。 C to 350 C, the reduction of heat loss was ranged from 5% to 25% for the half-exposed digester, while from 10% to 28% for the fully underground digester. 6.In the comparison of heat loss between the half-exposed and underground digesters, the heat loss from the former was fr6m 1,6 to 2, 6 times as much as that from the latter. This leads to the evidence that the underground digester takes advantage of heat conservation during winter.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.208-218
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• 2012

Numerical simulation technique has been developed to calculate microwave backscattering from water surface. The simulation plays a role of a substitute for experiments. Validation of the simulation was shown by comparing with experimental results. Water area observations by microwave radar have been simulated to evaluate algorithms and systems. Furthermore, the simulation can be used to understand microwave scattering mechanism on the water surface. The simulation has applied to the various methods for water area observations, and the utilizations of the simulation are introduced in this paper. In the case of fixed radar, we show following examples, 1. Radar image with a pulse Doppler radar, 2. Effect of microwave irradiation width and 3. River observation (Water level observation). In addition, another application (4.Synthetic aperture radar image) is also described. The details of the applications are as follows. 1. Radar image with a pulse Doppler radar: A new system for the sea surface observation is suggested by the simulation. A pulse Doppler radar is assumed to obtain radar images that display amplitude and frequency modulation of backscattered microwaves. The simulation results show that the radar images of the frequency modulation is useful to measure sea surface waves. 2. Effect of microwave irradiation width: It is reported (Rheem[2008]) that microwave irradiation width on the sea surface affects Doppler spectra measured by a CW (Continuous wave) Doppler radar. Therefore the relation between the microwave irradiation width and the Doppler spectra is evaluated numerically. We have shown the suitable condition for wave height estimation by a Doppler radar. 3. River observation (Water level observation): We have also evaluated algorithms to estimate water current and water level of river. The same algorithms to estimate sea surface current and sea surface level are applied to the river observation. The simulation is conducted to confirm the accuracy of the river observation by using a pulse Doppler radar. 4. Synthetic aperture radar (SAR) image: SAR images are helpful to observe the global sea surface. However, imaging mechanisms are complicated and validation of analytical algorithms by SAR images is quite difficult. In order to deal with the problems, SAR images in oceanic scenes are simulated.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.9-15
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• 2010

This study was conducted to develop a stand growth model and a stand yield table for Eucalyptus pellita and Acacia mangium plantations in Kalimantan, Indonesia. To develop a stand growth model, Weibull robability density function, a diameter class model, was applied in this study. In the development of stand growth model by site index and stand age, a hierarchy is generally required - estimation, recovery and prediction of the diameter class model. A number of grow equations were also involved in each process to estimate diameter, height, basal area, minimum or maximum diameter. To examine whether the grow equations are adequate for Eucalyptus pellita or Acacia mangium plantations, a fitness index was analyzed for each equation. The results showed that fitness indices were ranged from 65 to 89% for Eucalyptus pellita plantations and from 72 to 95% for Acacia mangium plantations. As being highly adequate for the plantations, a stand yield table was developed based on the resulted growth model, and applied to estimate the stand growth with midium site index for 10-year period. The highest annual stand growth of Eucalyptus pellita plantations was estimated to be 21.25 $m^3$/ha, while that of Acacia mangium plantations was 27.5 $m^3$/ha. In terms of annual stand growth, Acacia mangium plantations appeared to be more beneficial than Eucalyptus pellita plantations. Also, to estimate commercial timber volume available from the plantations, an assumption that a log would be cut by 2.7 m in length and the rest of the log would be cut by 1.5m was involved. The commercial timber volume available from Eucalyptus pellita plantations was 68.0 $m^3$/ha, 33% from the total stand volume, 203.2 $m^3$/ha. Also 96.7 $m^3$/ha of commercial timbers were available from Acacia mangium plantations, which was 42% from the 232.9 $m^3$/ha in total. Presenting a good information about the stand growth in Eucalyptus pellita and Acacia mangium plantations, this study might be useful for whom proceeds or considers an abroad plantation for merchantable timber production or carbon credit in tropical regions.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.2
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• pp.124-134
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• 2005

To investigate the exposure effect of polynuclear aromatic hydrocarbons (PAHs), we measured airborne total PAHs as an external dose, urinary 1-hydroxypyrene (1-OHP) as an internal dose of PAHs exposure, and analyzed the relationship between urinary 1-OHP concentration and PAHs exposure. The study population contained 44 workers in steel-pipe coating and paint manufacture industries. The airborne PAHs was obtained during survey day, and urine were sampled at the end of shift. Personal information on age, body weight, height, eniployment duration, smoking habit, and alcohol consumption was obtained by a structured questionnaire. Airborne PAHs were analyzed by the gas chromatograph with mass selective detector. Urinary 1-OHP levels were analyzed by the high performance liquid chromatograph with ultraviolet wavelength detector. For statistical estimation, t-test, ${\chi}^2$-test, analysis of variance, correlation analysis, arid regression analysis were executed by SPSS/PC (Windows version 10). The mean of environmental total PAHs was $87.8{\pm}7.81{\mu}g/m^3$. The mean concentration ($526.5{\pm}2.85{\mu}g/m^3$) of workers in steel-pipe coating industries using coal tar enamel was the higher than that ($17.5{\pm}3.36{\mu}g/m^3$) of workers in paint manufacture industries using coal tar paint. The mean of urinary 1-OHP concentration ($51.63{\pm}3.144{\mu}\;mol/mol$ creatinine) of workers in steel-pipe coating industries was the higher than that ($2.33{\pm}4.709{\mu}\;mol/mol$ creatinine) of workers in paint manufacture industries. The mean of urinary 1-OHP concentration of smokers was the higher than that of non-smokers. There was significant correlation between the urinary concentration of 1-OHP and the environmental concentration of PAHs (r=O.S48, p<0.001), pyrene(r=0.859, p<0.001), and urinary cotinine (r=0.324, p<0.05). The regression equation between the urinary concentration of 1-OHP in ${\mu}g/g$ creatinine($C_{1-OHP}$) and airborne concentration of PAHs (or pyrene) in ${\mu}g/m^3$ ($C_{PAHs}$ or Cpyrene) is: Log ($C_{1-OHP}$)=-0.650+0.889×Log($C_{PAHs}$), where $R^2=0.694$ and n=38 for p<0.001.Log ($C_{1-OHP}$)=1.087+0.707${\times}$Log(Cpyrene), where $R^2=0.713$ and n=38 for p<0.001. From the results of stepwise multiple regression analysis about 1-OHP, significant independents were total PAHs and urinary cotinine (adjusted $R^2=0.743$, p<0.001). In this study, there were significant correlation between the urinary concentration of 1-OHP and the airborne concentration of PAHs. The urinary 1-OHP was effective index as a biomarker of airborne PAHs in workplace. But it was influenced by non-occupational PAHs source, smoking.

• Journal of Animal Science and Technology
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• v.51 no.5
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• pp.345-352
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• 2009

This study utilized 332,625 records of linear type scores consisting for 15 primary traits, 22,175 final score and 84,612 pedigree information of 22,175 Holstein cows from 1993 to 2007 in Korea to estimate genetic parameters for 16 type traits. Genetic and error (co)variances between two traits selected from 16 traits were estimated using bi-trait pairwise analyses with DFREML package. The estimated heritabilities for stature (ST), strength (STR), body depth (BD), dairy form (DF), rump angle (RA), thurl width (TW), rear legs side view (RLSV), foot angle (FA), fore udder attachment (FUA), rear udder height (RUH), rear udder width (RUW), udder cleft (UC), udder depth (UD), front teat placement (FTP), front teat length (FTL) and final score (FS) were 0.31, 0.21, 0.25, 0.10, 0.29, 0.19, 0.09, 0.06, 0.12, 0.13, 0.12, 0.08, 0.26, 0.20, 0.28 and 0.15, respectively. ST had the highest positive genetic correlation with BD (0.90), while RLSV had the highest negative genetic correlation with FA (-0.56). RA had negative genetic correlation with most udder traits (-0.17~-0.02). Especially, RUW had the higher positive genetic correlation with STR (0.60), BD (0.62), and TW (0.49), however, UD had the higher negative genetic correlation with STR (-0.40) and BD (-0.40). FTL had negative genetic correlation with FUA, RUH, RUW, UC and UD. FS had positive genetic correlation with UC, UD and FTP (0.12, 0.18 and 0.20). However, additional research is needed on the use of these parameters in the genetic evaluation because estimated genetic and error variance-covariance matrices were not positive definite.