• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.229-234
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• 2018

BACKGROUND: in vitro micronucleus test (vitMNT) is one of the promising alternative testing methods in genotoxicity test and was adopted as OECD test guideline for chemical registration. This study was conducted to optimize the cytoplasm conditions in vitMNT using Chinese hamster lung (CHL) cell. METHODS AND RESULTS: In this study cytokinesis-block micronucleus test was conducted. Mitomycin C and colchicine were used as positive control chemicals and were treated for three hours (short time) or twenty-four hours (long time). Giemsa solution was used for cell staining. For optimization of vitMNT, the final fixative was prepared as five concentrations (0%, 1%, 3%, 5%, and 25%) of acetic acid in methanol, and treatment times of the final fixative were varied under four conditions (immediately, one hour, four hours, and one day). CONCLUSION: Acetic acid at 1% in methanol as the final fixative was most adequate to preserve the cytoplasm around the nucleus in the interphase cells. Also, fixative treatment time of cell suspension for one to four hours may minimize the cell rupture. These results can be helpful for getting an accurate result promptly due to clear visual distinction to score micronucleus in vitMNT using giemsa solution.

• Journal of the Korean Geotechnical Society
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• v.24 no.6
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• pp.77-84
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• 2008

The existing equations for radial consolidation cannot account for the changes of well resistance with time and cannot predict the appropriate in-situ consolidation curve. In this study, small cylinder cell tests are performed to evaluate the discharge capacity of PVD. Also, a block sample of 1.2 m in diameter and 2.0 m in height was consolidated to observe the change in the drainage capacity with time for three types of PVD. From the test results on a block sample, the drainage curves normalized with initial drainage of each PVD are similar, regardless of the PVD type and the consolidation curve, which is predicted using solutions of radial consolidation based on the discharge capacity measured in a small cylinder cell tests, significantly overestimates the degree of consolidation. The term of well resistance in the radial consolidation solution was back-calculated to fit the consolidation curve of a large block sample and it is defined as the time dependent well resistance factor, L(t). The L(t) was found to be linearly proportional to the dimensionless time factor, Th. It was also shown that the consolidation curve evaluated by using L(t) provides more accurate prediction than the existing solution.

• Convergence Security Journal
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• v.12 no.5
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• pp.87-97
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• 2012

Privacy of personal information disclosure incident occurs frequently as a problem to our society's most important and sensitive social agenda is emerging. Personal information is actually more accurate, depending on the type or types of economic value and sensitivity, the quality of the information, because it can cause a spill a serious social threat and systematic personal information protection and management are not carried out and the information society in a big mess can result. Customers my affairs when small guard security companies, especially the sensitive personal information of customers who need to work, the collected information be leaked or the company's trade secrets, are exposed on the outside, it could be a serious threat to a greater problem cause. Small escort guard companies, however, compared with large companies to build its own security system, due to issues such as the extent of funding, staffing shortages, there are many difficulties. Status of Information Security, scale and analyze the characteristics of small escort guard companies occupied by guard security companies in the present study, sleep, look at him in the solution of the practical issues of information protection system laid small guard. Expenses supplier of propose a security system for preventing the leakage of personal information.

• Korean Journal of Agricultural Science
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• v.43 no.1
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• pp.116-126
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• 2016

The objective of this study is to predict the fuel efficiency of an agricultural tractor. The fuel efficiency of the tractor during rotary tillage was predicted using numerical modeling. A numerical model was developed using Simulation X. Based on tractor power flow, numerical modeling consisted of an engine, transmission, PTO (power take off), and hydraulics. The specifications of major components utilized in the numerical model were the same as those of a 71 kW tractor (field test tractor). The load that was inputted for fuel efficiency prediction into the simulation model was obtained from a field test. Fuel efficiency predictions were conducted by comparing field test results and simulation results. In addition, it was performed by dividing the rotary tillage and steering section. Main results are as follows: first, t-values of engine torque were measured to be 0.31 in the rotary tillage and 0.92 in the steering section. Second, t-values of fuel consumption were measured to be 0.51 and 5.41 in the rotary tillage and the steering section, respectively. Finally, t-values of fuel efficiency were measured to be 1.72 and 40 in the rotary tillage and the steering section, respectively. The results show no significant differences with t-values of less than 5% in the rotary tillage. But, it shows significant differences in the steering section. Therefore, simulation for accurate fuel efficiency prediction requires a suitable algorithm or detailed design of the simulation model in the steering section.

• Journal of Environmental Impact Assessment
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• v.17 no.5
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• pp.271-278
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• 2008

The purpose of this research provides the basic solution about waterfront and promotes the inherent capability, that recoveries both the river and gives the river for water quality to improve plan. In this study, we compare and analysis the slope contact between filter media of the porous concrete and planting concrete. As a result, when appling the porous concrete, it can show the removal efficiency is SS 53%, BOD 39%, COD 20%, T-N 36% T-P 42% and appling planting concrete is SS 58%, BOD42%, COD 26%, T-N 45%, T-P 53%. Therefore, planting concrete is higher removal efficiency (SS 5%, BOD 3%, COD 6%, T-N 9%, T-P 10%) than porous concrete. The experimental results show that using purification filter media on planting concrete is better than on porous concrete, because it have the higher purification filter efficiency. The quality of water improves vegetarian concrete, that can expect the increase of the self-purification capacity and improve the spectacle for providing the waterside and planting of planting concrete. In addition, it can complete and apply the research if having enough time for experimentation and accurate study for mechanism by plant, we can use both planting concrete filter media and the existing dike. As a result, we can gain the better quality of the water of the city's rivers and good economic value, that is spread by all cities applicable technologies. So it can be expected using well for future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4411-4417
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• 2012

The present study proposes the optimization of wing structure base on reduced model which assures the solution accuracy and computational efficiency. Well-constructed reduced model assures the accurate result in the eigenvalue problem, dynamic analysis or sensitivity of design optimization. Reduced system is classified into the reduce-order model based on structural modes and the reduced system based on degrees of freedom. Because this study uses the reduced system based on degrees of freedom, it is important to select the dominant degrees of freedom properly. For this work, robust selection method, two-level selection scheme, is employed and IRS(Improved Reduced System) is applied to construct the final reduced system. In the optimization process based on the reduced system, all of the equivalent stress, eigenvalue and design sensitivities are calculated from the reduced system. Through a numerical example, it is shown that the present optimization methodology based on the reduction method can provide an optimal results for objective function satisfying constraint condition.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.2 s.302
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• pp.1-10
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• 2005

The current implementation of TCP for the Internet is not efficient when used for Mobile Ad hoc Networks (MANENTs). This is because TCP assumes that all packet losses are caused by congestion, whereas transmission errors are a main reason for packet losses in wireless networks. To remedy this situation and increase performance, we propose an end-to-end method of using propagation delays and the differences between propagation delays to distinguish the causes for packet losses. The proposed method has two characteristics: Firstly, it is energy-efficient because this solution is only initiated when a packet loss is detected. Secondly, our approach considers only the one way propagation delay and is more accurate in determining causes for packet losses than existing methods which consider round trip time. Petri net models of the proposed TCP and of the standard TCP have been built and simulations have been performed on them. Our simulation results show that the proposed approach increases throughput and reduces propagation delay compared with standard TCP.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.304-308
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• 2014

Accurate prediction of peak bloom dates (PBD) of flowering cherry trees is critical for organizing local cherry festivals and other associated cultural and economic activities. A two-step phenology model is commonly used for predicting flowering time depending on local temperatures as a result of two consecutive steps followed by chill and heat accumulations. However, an extensive computation requirement for parameter estimation has been a limitation for its practical use. We propose a sequential parameterization method by exploiting previously unused records of development stages. With an extra constraint formed by heat accumulation between two intervening stages, each parameter can then be solved sequentially in much shorter time than the brute-force method. The result was found to be almost identical to the previous solution known for cherry trees (Prunus ${\times}$ yedoensis) in the Tidal Basin, Washington D.C.

• Journal of the Korean Society of Safety
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• v.35 no.1
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• pp.97-106
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• 2020

The objective of this paper is to suggest a new quantification method for multi-unit probabilistic safety assessment (PSA) that removes the overestimation error caused by the existing delete-term approximation (DTA) based quantification method. So far, for the actual plant PSA model quantification, a fault tree with negates have been solved by the DTA method. It is well known that the DTA method induces overestimated core damage frequency (CDF) of nuclear power plant (NPP). If a PSA fault tree has negates and non-rare events, the overestimation in CDF drastically increases. Since multi-unit seismic PSA model has plant level negates and many non-rare events in the fault tree, it should be very carefully quantified in order to avoid CDF overestimation. Multi-unit PSA fault tree has normal gates and negates that represent each NPP status. The NPP status means core damage or non-core damage state of individual NPPs. The non-core damage state of a NPP is modeled in the fault tree by using a negate (a NOT gate). Authors reviewed and compared (1) quantification methods that generate exact or approximate Boolean solutions from a fault tree, (2) DTA method generating approximate Boolean solution by solving negates in a fault tree, and (3) probability calculation methods from the Boolean solutions generated by exact quantification methods or DTA method. Based on the review and comparison, a new intersection removal by probability (IRBP) method is suggested in this study for the multi-unit PSA. If the IRBP method is adopted, multi-unit PSA fault tree can be quantified without the overestimation error that is caused by the direct application of DTA method. That is, the extremely overestimated CDF can be avoided and accurate CDF can be calculated by using the IRBP method. The accuracy of the IRBP method was validated by simple multi-unit PSA models. The necessity of the IRBP method was demonstrated by the actual plant multi-unit seismic PSA models.

• Journal of the Korea Society for Simulation
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• v.28 no.4
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• pp.21-32
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• 2019

Inspired by the social behavior models of a bird flock or fish school, particle swarm optimization (PSO) is a popular metaheuristic optimization algorithm and has been widely used from solving a complex optimization problem to learning a artificial neural network. However, PSO is difficult to apply to many real-life optimization problems involving stochastic noise, since it is originated in a deterministic environment. To resolve this problem, this paper incorporates a resampling method called the uncertainty evaluation (UE) method into PSO. The UE method allows the particles to converge on the accurate optimal solution quickly in a noisy environment by selecting the particles' global best position correctly, one of the significant factors in the performance of PSO. The results of comparative experiments on several benchmark problems demonstrated the improved performance of the propose algorithm compared to the existing studies. In addition, the results of the case study emphasize the necessity of this work. The proposed algorithm is expected to be effectively applied to optimize complex systems through digital twins in the fourth industrial revolution.