• Korean Chemical Engineering Research
• /
• v.47 no.6
• /
• pp.781-787
• /
• 2009

This report investigates the economic proprieties of commercial 50,000 barrel per day direct/indirect coal liquefaction(DCL/ICL) plants to produce commercial-grade diesel and naphtha liquids. The scope of the study includes capital and operating cost estimates, sensitivity analyses and a comparative financial analyses. Based on plant capacity of 50,000BPD, employing Illinois #6 bituminous coal as feed coal, the total capital cost appeared $3,994,858,000(DCL) and $4,962,263,000(ICL). Also, the internal rate of return of DCL/ICL appeared 13.27% and 12.68% on the base condition respectively. In this case, coal price and sale price of products were the most influence factors. And ICL's payback period(6.8 years) was longer than DCL's(6.6 years). According to sensitivity analyses, the important factors on both DCL/ICL processes were product sale price, feed coal price and the capital cost in order.

• Journal of the Korean Data and Information Science Society
• /
• v.28 no.6
• /
• pp.1349-1360
• /
• 2017

This study was conducted to estimate the genetic parameters for common ketosis indicators (${\beta}$-hydroxybutyrate acid, BHBA; milk acetone), feed intake efficiency indicator (energy-corrected milk, ECM), and milk yield (MY) in Korean Holstein. A total of 75,072 monthly test-day records from 14,397 first parity cows were collected, between 2012 and 2016, from Korea animal improvement association enrolled farms. Variance components were estimated using a multiple trait random regression model. The heritability of BHBA and acetone levels ranged from 0.06 to 0.15 at different DIMs. The phenotypic and genetic correlations between BHBA and acetone were between 0.73 and 0.90, and between 0.93 and 0.98, respectively. The phenotypic correlation between BHBA and MY, between acetone and MY, between BHBA and ECM, and between acetone and ECM ranged from -0.18 to -0.05, -0.23 to -0.05, 0 to 0.10, and -0.09 to 0.01, respectively. Genetic correlation estimates between BHBA and MY, between acetone and MY, between BHBA and ECM, and between acetone and ECM also ranged from -0.55 to 0.05, -0.62 to -0.04, -0.10 to 0.11, and -0.20 to 0.00, respectively. We hope that these results would greatly assist in the improvement of ketosis disease in the local Holsteins.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.9 no.3
• /
• pp.148-153
• /
• 2006

This study dealt with the measurement of exhausted gas concentration, the estimation of a combustion efficiency, and the review of IMO indexing. We concentrated on establishing the basic data to take a counterplan coping with $CO_2$ regulations. The average combustion efficiency was 98% in shop test of new engines and 96.5% in sea trial test of new ships, respectively. It would become lower for the old engine or/and ship. High combustion efficiency results in high $CO_2$ emission and low combustion efficiency results in high emission of incomplete combustion products. The efficient method reducing $CO_2$ emission without an increase in noxious air pollutants would be the development of a substitute fuel and the fuel-efficient and economical engine, and the fair play among shipping agencies in a ship speed. In reviewing of IMO indexing, it is necessary to begin by analyzing the carbon content of a marine fuel for a precise estimates.

• Geophysics and Geophysical Exploration
• /
• v.9 no.4
• /
• pp.304-315
• /
• 2006

We have examined the applicability of f-k analysis to the GPR direct wave measurement for water content to characterize vadose zone condition. When the vadose zone consists of a dry surface layer over wet substratum, we obtained f-k spectra where most of the energy is bounded by the air and dry soil velocities. In this case, dry soil velocity was successfully estimated by using high frequency data. On the other hands, when wet soil overlies dry substratum, the f-k spectra show a contrasting response where most of the energy travels with the velocity bounded by dry and wet soil velocities. In this case, the radar waves are trapped and guided within wet soil layer, exhibiting velocity dispersion. By adopting modal propagation theory, we could formulae a simple inversion code to find two layer's dielectric constants as well as layer thickness. By inverting the velocity dispersion curve obtained from f-k spectra of synthetic modeling data, we could obtain good estimates of dielectric constants of each layer as well as first layer thickness. Moreover, we could obtain more accurate results by including the higher mode data. We expect this method will be useful to get the quantitative property of real subsurface when the field condition is similar.

• Environmental and Resource Economics Review
• /
• v.29 no.4
• /
• pp.499-520
• /
• 2020

Input ratio of electricity to other production inputs in the Korean manufacturing sector has been higher than for the other OECD countries. In addition, electricity prices in Korea has been relatively lower than the average of OECD countries. Moreover, electricity sector is responsible for most CO2 emissions in Korea as coal and natural gas account 41.9% and 26.8% of electricity production as of 2018. Therefore, it looks inevitable to raise the electricity tariff for the manufacturing sector in Korea, but there is a concern that increase in the electricity tariff might affect small and medium enterprises (SMEs) more than large firms. This study estimates electricity demand's price and output elasticities for large firms and SMEs in steel industry by employing a time varying parameter model (Kalman filter). The analysis shows that changes in output levels regardless of firms' size affect electricity demands more significantly than do changes in electricity prices. Second, large firms have higher variances for both price and output elasticities of electricity demand. Third, large firms have higher price elasticity but lower output elasticity of electricity demand relative to SMEs. Policy implications are suggested in association with how to reduce electricity demands in the energy-intensive industry.

• KDI Journal of Economic Policy
• /
• v.34 no.2
• /
• pp.55-93
• /
• 2012

In Korea, energy policies are actualized through various energy-related plans. Recently, however, as high-ranking plans, which are very vision-oriented, continually set higher sector-by-sector goals, subordinate action plans, which require consistency, encounter distortions in their establishment process. Also, each subordinate action plan reveals limitations in terms of securing flexibility of the plan in responding to uncertainties of the future. These problems pose potential risks such as causing huge social costs. In this regard, with an aim to provide empirical evidence for discussions on improving the procedure for developing and executing Korea's energy plans, this study mainly analyzes the Basic Plan on Electricity Demand and Supply-one of the most important subordinate action plans-in order to explain the problems of the Basic Plan in a logical manner, and potential problems that could occur in the process of sustaining consistency between the Basic Plan and its higher-ranking plans. Further, this paper estimates the scale of social costs caused by those problems assuming realistic conditions. According to the result, in the case of where maximum electric power is estimated to be 7% (15%) less than the actual amount in the Basic Plan on Electricity Demand and Supply, the annual generation cost will rise by 286 billion won and (1.2 trillion won) in 2020. Such social costs are found to occur even when establishing and executing the Basic plan according to the target goal set by its higher-ranking plan, the National Energy Master Plan. In addition, when another higher-ranking GHG reduction master plan requires the electricity sector to reduce emissions by additional 5% in the GHG emissions from the right mix in electricity generation with 'zero' cost of carbon emission, the annual generation cost will rise by approximately 915 billion won in 2020. On the other hand, the analysis finds that since economic feasibility of electric powers in Korea varies significantly depending on their type, Korea is expected to face very small potential social costs caused by uncertainties over the future price of carbon dioxide in the process of establishing the Basic Plan.

• Economic and Environmental Geology
• /
• v.27 no.6
• /
• pp.557-561
• /
• 1994

Q estimates are made by direct measurements of energy loss per cycle from primary P and S waves, as a function of frequency. Assuming that intrinsic Q is frequency independent and scattering Q is frequency dependent over the frequencies of interest, the relative contributions of each, to a total observed Q, may be estimated. Test examples are produced by computing viscoelastic synthetic seismograms using a pseudo spectral solution with inclusion of relaxation mechanisms (for intrinsic Q) and a fractal distribution of scatterers (for scattering Q). The composite theory implies that when the total Q for S-waves is smaller than that for P-waves (the usual situation), intrinsic Q is dominating; when it is larger, scattering Q is dominating. In the inverse problem, performed by a global least squares search, intrinsic $Q_p$ and $Q_s$ estimates are reliable and unique when their absolute values are sufficiently low that their effects are measurable in the data. Large $Q_p$ and $Q_s$ have no measurable effect and hence are not resolvable. Standard deviation of velocity $({\sigma})$ and scatterer size (A) are less unique as they exhibit a tradeoff as predicted by Blair's equation. For the P-waves, intrinsic and scattering contributions are of approximately the same importance, for S-waves, the intrinsic contributions dominate.

• Proceedings of the KOR-KST Conference
• /
• 1996.02a
• /
• pp.59-86
• /
• 1996

Current methods for evaluating unsignalized intersections, and estimating level-of-service (LOS) is determined from efficiency-based criteria such as little or no delay to very long delays. At present, similar procedures to evaluate intersections using safety-based criteria do not exist. The improvement of sight distances at intersections is the most effective way of improving intersection safety. However, a set of procedures is necessary to account for the limitations in current methodology. Such an approach would build upon such methods, but also account for: deficiencies in the current deterministic solution for the determination of intersection sight distances; opportunity for an accident and severity of an accident; and cost-effectiveness of attaining various levels of sight distances. In this research, a model that estimates the degree of safety at two-way stop-controlled intersections is described. Only crossing maneuvers are considered in this study because accidents caused by the crossing maneuvers are the dominate type among intersection accidents. Monte Carlo methods are used to estimate the hazard at an intersection as a function of roadway features and traffic conditions. Driver`s minimum gap acceptance in the crossing vehicles and headway distribution on the major road are used in the crossing vehicles and headway distribution on the major road are used in the model to simulate the real intersectional maneuvers. Other random variables addressed in the model are: traffic speeds; preception-reaction times of both drivers in the crossing vehicles and drivers in oncoming vehicles on the major road; and vehicles on the major roads. The developed model produces the total number of conflicts per year per vehicle and total potential kinetic energy per year per vehicle dissipated during conflicts as measurements of safety at intersections. Based on the results from the developed simulation model, desirable sight distances for various speeds were determined as 350 feet, 450 feet and 550 feet for 40 mph, 50 mph and 60 mph prevailing speed on the major road, respectively. These values are seven to eight percent less than those values recommended by AASHTO. A safety based level-of-service (LOS) is also developed using the results of the simulation model. When the total number of conflicts per vehicle is less than 0.05 at an intersection, the LOS of the intersection is `A' and when the total number of conflicts per vehicle is larger than 0.25 at an intersection, the LOS is `F'. Similarly, when the total hazard per vehicle is less than 350, 000 1b-ft2/sec2, the LOS is `F'. Once evaluation of the current safety at the intersection is complete, a sensitivity analysis can be done by changing one or more input parameters. This will estimate the benefit in terms of time and budget of hazard reduction based upon improving geometric and traffic characteristics at the intersection. This method will also enable traffic engineers in local governments to generate a priority list of intersection improvement projects.

• Journal of Wetlands Research
• /
• v.21 no.spc
• /
• pp.28-38
• /
• 2019

Climate change on the Korean peninsula is progressing faster than the global average. For example, typhoons, extreme rainfall, heavy snow, cold, and heatwave that are occurring frequently. North Korea is particularly vulnerable to climate change-related natural disasters such as flooding and flooding due to long-term food shortages, energy shortages, and reckless deforestation and development. In addition, North Korea is classified as an unmeasured area due to political and social influences, making it difficult to obtain sufficient hydrologic data for hydrological analysis. Also, as interest in climate change has increased, studies on climate change have been actively conducted on the Korean Peninsula in various repair facilities and disaster countermeasures, but there are no cases of research on North Korea. Therefore, this study selects watershed characteristic variables that are easy to acquire in order to apply localization model to North Korea where it is difficult to obtain observed hydrologic data and estimates parameters based on meteorological and topographical characteristics of 16 dam basins in South Korea. Was calculated. In addition, as a result of reviewing the applicability of the parameter estimation equations calculated for the fifty thousand, Gangneungnamdaecheon, Namgang dam, and Yeonggang basins, the applicability of the parameter estimation equations to North Korea was very high.

• Journal of Nutrition and Health
• /
• v.37 no.10
• /
• pp.917-927
• /
• 2004

This study was performed to examine component of variance in nutrient intakes and to estimate the level of accuracy with varying degree of precision in order to achieve estimates of usual nutrient intakes. Three-day dietary records including both weekdays and weekends were collected every 4 season over a I-year period from 36 males and 93 females aged 40 - 65 y. For each nutrient, we partitioned total intake variance into weekly (weekday vs weekend), seasonal, within- and between- individual variation as components of variance, using analysis of variance. It was found that major components of variance were within- and between-individual variation. Particularly, within-individual variation (57.2 - 87.1 %) was greater than between-individual variation (12.2 - 37.4%) for all nutrients. Weekly and seasonal variation contributed small components of variance for most nutrients. For protein, fat and carbohydrate, there were a little significant weekly variation (0.00 - 1.35%) in females but not in males. For some micronutrients, there were moderately significant seasonal variation (0.15 - 5.48%) in both sexes. Ratio of within- to between- individual variation ranged 1.4 (vitamin B$_2$) -4.5 (vitamin B$_1$) in males and 1.6 (carbohydrate) -2.9 (fat) in females. With total 12-day dietary records data, the maximum percentage deviation of observed intakes from usual (true) intakes ranged 12-37%. To estimate usual individual intakes within 20% of the true mean with 90% confidence level, 3 - 9 days of dietary survey were required for energy, protein, carbohydrate, phosphorus and iron, 13 - 19 days for fat and calcium, 25 - 29 days for vitamin A and vitamin C. Correlation coefficients between observed and true nutrient intakes were 0.71 - 0.91 for males, 0.81-0.91 for females. In conclusion, mean intakes of several nutrients can be reliably measured with the record method, using a limited number of days. Both nutrients of interest and the primary objectives should be taken account when planning method of assessment and number of replicates.