• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.7
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• pp.49-56
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• 2003

Nonpoint source pollutant loading from watershed may cause a problem to the water quality of the reservoir and stream. The characteristics of stream flow and water quality were monitored to investigate the runoff loading of the Namdae-cheon watershed from May in 1999 to October in 2003. Stage-discharge rating curve at the stream gauging site was established, and annual stream runoff of the study watershed was estimated as 499.4∼1,330.8mm during four years. The concentrations of total-nitrogen and total-phosphorus of stream water quality ranged from 0.76 to 6.95mg/L and from 0.0010 to 0.2276 mg/L, respectively, where T-N was generally higher than the water quality standard 1.0 mg/L for agricultural water use. The loads by unit generation of pollutant mass with respect to population, livestock, land use in this watershed were calculated. The runoff pollutant loadings by concentrations of total-N and total-P were estimated during study period, where the annual runoff loading of total-P was much less than the load by pollutant mass unit generation. The relations between stream discharge and water quality were analysed, and there was a high correlation for total-N but low for total-P. These results will be used to develop the monitoring techniques and water quality management system of agricultural watershed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.1
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• pp.8-16
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• 2013

We consider a problem of presort and loading of commercial bulk mails in a mailing service. Here, presort is the process by which a mailer prepares mail so that it is sorted to at least the finest extent required by the mailing service provider for the (discounted) price claimed. The problem is formulated as a special type of transportation problem. To solve industrial-sized problems, we develop an efficient heuristic algorithm and perform experimental tests on randomly generated problem instances. Results of the tests show that mailers can save mailing cost much more when they use small-sized mail trays with less frequent mailings. Also, large-sized mailers can obtain much more cost saving than small-sized mailers. In addition, cost saving effect is influenced by delivery area distribution of mails and fluctuation of mailing demand.

• Management Science and Financial Engineering
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• v.5 no.1
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• pp.1-25
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• 1999

There is a worldwide trend to automate the handling operations in port container terminals in an effort to improve productivity and reduce labor cost. This study iscusses how to apply an AGV(automated guided vehicle) system to the handling of containers in the yard of a port container ter-minal. The main issue of this paper is how to assign tasks of container delivery to AGVs during ship operations in an automated port container terminal. A dual-cycle operation is assumed in which the loading and the discharging operation can be performed alternately. Mixed integer linear program-ming formulations are suggested for the dispatching problem. The completion time of all the dis-charging and loading operations by a quayside crane is minimized, and the minimization of the total travel time of AGVs is also considered as a secondary objective. A heuristic method using useful properties of the dispatching problem is suggested to reduce the computational time. The perfor-mance of the heuristic algorithm is evaluated in light of solution quality and computation time.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.3
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• pp.241-247
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• 2011

Marine casualties of vessel are said to be in most case caused by human error, but it would be valid for the assumption that the ship is built with high quality and then should be acceptable to the safety standards. It means that the inherent characteristics of a ship should be the first consideration on the safety of ship. Therefore it is basically necessary for navigator to grasp the inherent stability of his ship and ensure that the ship complies with the minimum statutory standards of stability. This study is to realize the stability of the Korean offshore large purseiner varying with loading conditions by the inclining data and some calculations. The author compared the stability of the ship with IMO criteria and domestic rule, and proposed some improvement for the safety of the ship. The results are summarized as follows ; The values of GM of the ship according to the loading condition in navigation satisfy both of the IMO criteria and the domestic rule, but in case of the area under the GZ curves between the heel angles of $30^{\circ}$ and $40^{\circ}$, and the heel angle occuring the maximum righting lever not satisfy the IMO rule at the fishing ground departure and arrival conditions in the haul in net situation. The initial metacentric height of the ship is very large, but the range of stability and the occurring angle of the maximum GZ are very small, so even small inclining can bring about the beam end. The best method of improvement for that is to increase the freeboard of the model among the variables.

• Journal of Environmental Science International
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• v.20 no.5
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• pp.589-598
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• 2011

Milyanggang mid-watershed is located in downstream of Nakdong river basin. The pollutants from that watershed have an direct effect on Nakdong river water quality and it's control is important to manage a water quality of Nakdong river. A target year of Milyanggang mid-watershed water environment management plan is 2013. To predict a water quality at downstream of Milyang river, we have investigated and forecasted the pollutant source and it's loading. There are some plan to construction the sewage treatment plants to improve the water quality of Milyang river. Those are considered on predicting water quality. As results, it is shown that the population of Milyanggang mid-watershed is 131,857 and sewerage supply rate is 62.2% and the livestock is 1,775.300 in 2006. It is estimated that the population is 123,921, the sewerage supply rate is 75.5% in 2013. The generated loading of BOD and TP is 40,735 kg/day and 2,872 kg/day in 2006 and discharged loading is 11,818 kg/day and 722 kg/day in 2006 respectively. Discharged loadings were forecasted upward 1.0% of BOD and downward 2.7% of TP by 2013. The results of water quality prediction of Milyanggang 3 site were 1.6 mg/L of BOD and 0.120 mg/L of TP in 2013. It is over the target water quality at that site in 2015 about 6.7% and 20.0% respectively. Consequently, there need another counterplan to reduce the pollutants in that mid-watershed by 2015.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.79-86
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• 2004

One of the most difficult tasks in pavement management information systems is establishing the links between performance measures of a structure and the design and construction inputs. In-situ pavement performance can be considered a response variable to many project input variables, such as design, construction, and traffic loading effects. If we are to fully understand the component of pavement performance and specify the inputs through design and construction specifications to achieve that performance we must develop quantitative relationship between input and response variables through a scientific, fully integrated Pavement Performance Analysis System (PPAS). Hence, the objective of this study is to design a database model required for developing an effective database template that will allow analysis of pavement performance measures based on design and construction information linked by location. In order to select the most appropriate database model, a conceptual database model (Entity Relationship Model) and dimensional model, which is believed to be the most effective modeling technique for data warehouse project, are designed and compared. It is believed that other state highway agencies could adopt the proposed design strategy for implementing a PPAS at the discretion of the state highway agencies.

• Journal of Environmental Health Sciences
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• v.35 no.5
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• pp.365-375
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• 2009

Agriculture reservoirs need a systematic approach that can control water purity and water improvement. The area under study, Bunam Lake exceeds the agricultural water standard level due to contamination from the upper stream. When the Taean Enterprise City was planned, the water quality improvement plan was applied to minimize the environmental change. However, in order to continuously maintain the water quality in the Bunam Lake, it was essential to apply the Total Pollution Load Management System (TPLMs). In order to achieve the targeted water quality in the Bunam Lake, standard flow rates and targeted water quality levels were applied to obtain the loading capacity which is as follows : BOD 1,891.2 kg/d, T-N 1,945.7 kg/d, T-P 131.7 kg/d. Also, the regional development load was calculated as, BOD 1,083.6 kg/d, T-N 942.2 kg/d, T-P 61.8 kg/d, which is required to be deceased :- by BOD 378.4 kg/d, T-N 198.9 kg/d, T-P 31.6 kg/d in order to safely achieve the targeted water quality in the Bunam Lake.

• Korean Management Science Review
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• v.13 no.2
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• pp.147-161
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• 1996

Due-date is an important factor in Flexible Manufacturing System scheduling. Even though most of researchers have focused part selection and loading problem using fixed due-date assignment rules, FMSs consist of multi-function machines which facilitate alternative processes. This research investigates interactions of three dispatching mechanisms, three NSS (Next Station Selection) rules and four due-date assignment rules using simulation. Both cost-based and time-based performance measures are considered in this research.

• Korean Management Science Review
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• v.26 no.1
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• pp.93-112
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• 2009

In this paper, a model is presented to estimate a cycle time for completing an operation in a new type of AS/RS which can handle very heavy loads by separating the mechnisms for vertical and horizontal movements. Considering loading/unloading time between devices, we generalize the previous work, Hu et al. [9], which neglected the transfer time. Through the numerical experiments for various situations, we find that the difference of the cycle times between two models is fairly large and conclude that the transfer time between devices cannot be neglected at all.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.2
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• pp.170-178
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• 2024

This study aimed to quantitatively analyze the risk using data from 329 safety accidents that occurred in aquaculture fisheries management vessels over the recent five years (2018-2022). For quantitative risk analysis, the Bayesian network proposed by the International Maritime Organization (IMO) was used to analyze the risk level according to the fishing process and cause of safety accidents. Among the work processes, the fishing process was analyzed to have the highest risk, being 12.5 times that of the navigation, 2.7 times that of the maintenance, and 8.8 times that of the loading and unloading. Among the causes of accidents, the hull and working environment showed the highest risk, being 1.7 times that of fishing gear and equipment, 4.7 times that of machinery and equipment, and 9.4 times that of external environment. By quantitatively analyzing the safety accident risks for 64 combinations of these four work processes and four accident causes, this study provided fundamental data to reduce safety accidents occurring in aquaculture fisheries management vessels.