• Journal of Korea Water Resources Association
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• v.44 no.7
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• pp.511-522
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• 2011

Two-dimensional shallow water model based on the cut cell and the adaptive mesh refinement techniques is presented in this paper. These two mesh generation methods are combined to facilitate modeling of complex geometries. By using dynamically adaptive mesh, the model can achieve high resolution efficiently at the interface where flow changes rapidly. The HLLC Reimann solver and the MUSCL method are employed to calculate advection fluxes with numerical stability and precision. The model was applied to simulate the extreme urban flooding experiments performed by the IMPACT (Investigation of Extreme Flood Processes and Uncertainty) project. Simulation results were in good agreement with observed data, and transient flows as well as the impact of building structures on flood waves were calculated with accuracy. The cut cell method eased the model sensitivity to refinement. It can be concluded that the model is applicable to the urban flood simulation in case the effects of sewer and stormwater drainage system on flooding are relatively small like the dam brake.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.490-498
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• 2010

Isotianil is a fungicide which has prevention effects against rice blast disease. In order to register this new pesticide, the series of toxicity data on animal testing were reviewed to evaluate its hazards to consumers and to determine its acceptable daily intake. Isotianil was almost excreted by urine and feces. It has low acute oral toxicity while has no skin toxicity and ocular irritation. Its skin sensitization was evaluated as slight. Genotoxicity of parent compound and metabolite was negligible. Chronic toxicity tests on rats and dogs showed changes of hematology, clinical biochemistry and liver weight. It had no reproductive and teratogenic effects. The estimation of Acceptable Daily Intake(ADI) is based on the lowest no-observed adverse effect level (NOAEL). The lowest NOAEL of 2.83 mg/kg bw/day was found in the twelve-months rats study. The NOAEL was based on increased liver weight and treatment-related effect on clinica chemistry finding at the nest higher dose level of 2.83 mg/kg bw/day. Therefore, it is considered appropriated to apply an uncertainty factor of 100 to the NOAEL 2.83 mg/kg bw/day from the rat study, resulting in an ADI of 0.028 mg/kg bw/day.

• Tunnel and Underground Space
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• v.15 no.4 s.57
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• pp.264-274
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• 2005

The optimum blasting pattern to excavate a quarry efficiently and economically can be determined based on the minimum production cost which is generally estimated according to rock fragmentation. Therefore it is a critical problem to predict fragment size distribution of blasted rocks over an entire quarry. By comparing various prediction models, it can be ascertained that the result obtained from Kuz-Ram model relatively coincides with that of field measurements. Kuz-Ram model uses the concept of rock factor to signify conditions of rock mass such as block size, rock jointing, strength and others. For the evaluation of total production cost, it is imperative to estimate 3-D spatial distribution of rock factor for the entire quarry. In this study, a sequential indicator simulation technique is adopted for estimation of spatial distribution of rock factor due to its higher reproducibility of spatial variability and distribution models than Kriging methods. Further, this can reduce the uncertainty of predictor using distribution information of sample data The entire quarry is classified into three types of rock mass and optimum blasting pattern is proposed for each type based on 3-D spatial distribution of rock factor. In addition, plane maps of rock factor distribution for each ground levels is provided to estimate production costs for each process and to make a plan for an optimum blasting pattern.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.497-508
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• 2014

The current study examined the relationships between task-approach skills of optimism, bearability, intolerance of uncertainty, career identity, career maturity, career barriers, and career aspiration. Data was collected from two-hundred sixty nine college students who matriculated in colleges located in Seoul, Gyeoungi and Chungchung provinces in Korea. The correlation analysis and multiple linear regression were carried out to explore the relationship among the variables mentioned above. The results of this study were as follows: First, career identity was positively correlated with career maturity, aspiration and negatively with career barrier. optimism was negatively correlated with career barrier. in addition, intolerance of uncertanity was positively correlated with career maturity. and negatively with career barriers. Second, multiple linear regression revealed that career identity, optimism and lacking intolerance of uncertanity significantly influenced career maturity, career identity, optimism and intolerance of uncertanity significantly influnced career barriers. In addition, only optimism influnced career aspiration. These findings implied that career counselors need to assist clients developing optimism, flexibility, bearability and counselors should be aware of the effect of task-approach skills on career, barriers, and aspiration. Further discussions regarding results are included.

• Journal of Korea Water Resources Association
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• v.38 no.12 s.161
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• pp.1039-1049
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• 2005

The objective of this study is to produce optimal radar-derived rainfall for hydrologic utilization. The ground clutter and beam blockage effects from Mt. Kwanak station (E.L 608m) are removed from radar reflectivities by POD analysis. The reflectivities are used to produce radar rainfall data in the form of rain rates (mm/h) by the application of the Marshall-Palmer reflectivity versus rainfall relationship. However, these radar-derived rainfall are underestimated in temporal and spatial scale compared with observed one, so it is necessary to hire a correction scheme based on the gauge-to-radar (G/R) statistical adjustment technique. The selected watershed for studying the real-time correction of radar-rainfall estimation is the Soyang dam site, which is located approximately 100km east of Kwanak radar station. The results indicate that adjusted radar rainfall with the gauge measurement have reasonal G/R ratio ranged on 0.95-1.32 and less uncertainty with that mean standard deviation of G/R ratio are decreased by $9-28\%$. Mean areal precipitation from adjusted radar rainfall are well agreed to the observed one on the Soyang River watershed. It is concluded that the real-time bias adjustment scheme is useful to estimate accurate basin-based radar rainfall for hydrologic application.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.384-398
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• 2016

The purpose of this study is to explore how school social workers recognize on the school violence of adolescents by using Q methodology. To this study, selected 31 of Q samples related school violence of adolescent by applying Q methodology and 33 of socials workers completed classification table, and three types were derived. The first type is named 'a type of improvement parents' concern with nonprofessional perception' because it has a significant part in bringing up children by parents to prevent school violence of adolescent and also has a negative perception, which is difficult to approach professional intervention. The second type is named 'a type of uncertainty of responsibility with passive perception' because there is an ambiguousness between responsibility and criteria through connection of official on the school violence. The third type is named 'a type of absence of responsibility with professional perception' because it is perceived absence of job roles to prevent school violence. This type showed school social workers, as a professionals of school violence of adolescents, wanted to intervene school violence but realistic intervention was difficult. From this study, it is considered subjective perception of school social workers on the school violence of adolescents will be affected on the change of adolescents in the future, and it is a significant way to use them as a basic data to prevent or remove school violence of adolescents in the school through conception and typology of them.

• Journal of Distribution Research
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• v.16 no.3
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• pp.33-75
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• 2011

The ownership structure of a franchise system is determined by the franchisor's strategic choice. A close look at the extant theories and perspectives in economics and management such as resource scarcity theory, agency theory, transaction cost analysis, and mixed ownership theory reveals that firms choose their ownership structure for the sake of economic efficiency, profit potentials, the chance of survival, and other strategic concerns. The present study, on the basis of strategic choice perspective, reviews the divergent theories of a franchise system's ownership structure and its determinants, thus providing a theoretical framework for comparing the contradictory arguments along the several critical dimensions. We also developed and tested the conflicting hypotheses regarding key determinants of ownership structure including firm's age, size, transaction-specific investments, uncertainty, and risk-sharing propensity. Using a FDD (Franchise Disclosure Document) data set of 543 Korean franchisors, we found that the years in business, the total number of employees, days of training, the inverse of the years of franchising, and the requirement of royalty payment have positive relationships with the proportion of company-owned outlets to total number of outlets. On the other hand, the proportion of company-owned outlets was found to have negative relationships with the total number of outlets and the extent of geographic dispersion of outlets, but to have no significant relationships with the initial investment required and the inverse of contract length. Based on the findings, we provide several theoretical and managerial implications for studying ownership structure of franchise systems.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.218-229
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• 2011

Lepimectin is a insecticide agent. In order to register this new pesticide, the series of toxicity data on animal testing were reviwed to evaluate its hazards to consumers and to determine its acceptable daily intake. Lepimectin was mostly excreted by feces. It has low acute oral toxicity while it has no dermal, ocular irritation and skin sensitization (As the result of subchronic, chronic toxicity and carcinogenicity showed changes of hematology and clinical biochemistry parameter of serum and blood.). Two-generation reproduction toxicity, genotoxicity, carcinogenicity and prenatal development toxicity were not proven. Therefore, the ADI for Lepimectin is 0.02 mg/kg/ bw/day, based on the NOAEL of 2.02 mg/kg/ bw/day of two-years carcinogenic toxicity study in rats and applying an uncertainty factor of 100.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.208-217
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• 2011

Pyrimisulfan is a herbicide. In order to register this new pesticide, the series of toxicity data on animal testing were reviewed to evaluate its hazards to consumers and also to determine its acceptable daily intake. Pyrimisulfan was excreted mostly by feces. It has low acute oral toxicity while it has no dermal, ocular irritation and skin sensitization (As the result of subchronic and chronic toxicity and carcinogenicity showed changes of hematology and liver.). Two-generation reproduction toxicity, genotoxicity, carcinogenicity and prenatal development toxicity were not proven. Therefore, the ADI for Pyrimisulfan is 0.1 mg/kg/ bw/day, based on the NOAEL of 10 mg/kg/ bw/day of 90-days repeated dose oral toxicity study in dogs while applying an uncertainty factor of 100.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.611-625
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• 2018

With innovative advances in wireless communication technology, many researches for extending network lifetime in maximum by using energy harvesting have been actively performed on the area of network resource optimization, QoS-guaranteed transmission, energy-intelligent routing and etc. As known well, it is very hard to guarantee end-to-end network delay due to uncertainty of the amount of harvested energy in multi-hop RF(radio frequency) energy harvesting wireless networks. To minimize end-to-end delay in multi-hop RF energy harvesting networks, this paper proposes an energy efficient routing metric based on interference aware and protocol which takes account of various delays caused by co-channel interference, energy harvesting time and queuing in a relay node. The proposed method maximizes end-to-end throughput by performing avoidance of packet congestion causing load unbalance, reduction of waiting time due to exhaustion of energy and restraint of delay time from co-channel interference. Finally simulation results using ns-3 simulator show that the proposed method outperforms existing methods in respect of throughput, end-to-end delay and energy consumption.