• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.599-617
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• 2006

A network model and a Genetic Algorithm(GA) is proposed to solve the simultaneous estimation of the trip distribution and traffic assignment from traffic counts in the congested networks in a logit-based Stochastic User Equilibrium (SUE). The model is formulated as a problem of minimizing the non-linear objective functions with the linear constraints. In the model, the flow-conservation constraints of the network are utilized to restrict the solution space and to force the link flows meet the traffic counts. The objective of the model is to minimize the discrepancies between the link flows satisfying the constraints of flow-conservation, trip production from origin, trip attraction to destination and traffic counts at observed links and the link flows estimated through the traffic assignment using the path flow estimator in the legit-based SUE. In the proposed GA, a chromosome is defined as a vector representing a set of Origin-Destination Matrix (ODM), link flows and travel-cost coefficient. Each chromosome is evaluated from the corresponding discrepancy, and the population of the chromosome is evolved by the concurrent simplex crossover and random mutation. To maintain the feasibility of solutions, a bounded vector shipment is applied during the crossover and mutation.

• Journal of the Korean Professional Engineers Association
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• v.15 no.4
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• pp.12-24
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• 1982

East Parts of Bangladesh have been benifited by low cost energy generated by domestic natural gas but West parts where energy generated by imported fuel. Bangladesh Government authority has very much concerned to transmit the low cost electricity to the West from the East for past several years. To solve such concerns, cross-country 230kv double circuits Power transmission line was proposed, however there was a big obstacle for the realization of this line to cross the Jamuna river which has 12 km long width with a deep muddy river bed. A consultant engineering firm named Merz-Mclellan anyway finalized this plan and a world-wide bid was announced on June 31, 1979. Due to the expected difficulty to construct the towers on sea like area, only three construction groups have participated. including a Korean joint venture organization of Samsung-Korean Developement corporation-Kolon Electric Machinery company. After 3 months bid evaluation, contract was awarded to Korean Consosium and KEM Co was in charge of designing steel towers with anchor bolts and base plates beside to electrical engineering field. Then KEM Co have faced and over-comed many unenpected technical difficulties such as forced eccentricity joint on base plate, distorsion issue of 60mm thick plates welding, threading anchor bolts, tad heat treatment of some anchor bolts, disagreement from Consultant Engineer on multiplying factor of leg stresses for 45$^{\circ}$ wind and on reducing O.L.F for wind loads on cables for such 1220km long spans. After spending two years long period for designing and engineering towers, base plates, and anchor bolts, first shipment of tower was finally realized on Nov. 8, 1981 and on the other hand KDD has proceeded concrete caisson work on schedule at Jamuna river site and expected to complete tower erection and stringing of cables within this year of 1982 which was original completion target.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.394-404
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• 2015

This study investigated the pharmacodynamics of betaine on the blood profile and short chain fatty acid levels in meat ducks exposed to heat wave. 400 heads of Cherry valley (Anasplatyrhynchos) meat ducks were completely randomized to 5 treatments (4 repetitions each), and were raised for 42 days. They were grouped into T1 (heat wave control group without betaine), T2 (betaine 400 ppm), T3 (betaine 800 ppm), T4 (betaine 1200 ppm), and T5 (normal control group without betaine). Compared to T1, the betaine addition groups showed higher body weight gain at shipment, with T3 showing the highest significant difference. For hematological indictors measured (red blood cells and platelets), the betaine addition groups showed significantly higher values than the heat wave control group. The pH of the former was lower but their electrolytes ($K^+$, $P^+$, and $Cl^-$) were significantly higher compared to the latter. For blood gas concentration, the former showed a significantly higher value than the latter. For the total short chain fatty acids, acetic acid, and propionic acid, the betaine addition groups and group fed broiler-high temperature diet showed higher values than the heat wave control group. On the other hand, the former showed significantly lower values in butyric acid, isobutyric acid, valeric acid, and isovaleric acid than the latter group. These results suggest that betaine has the pharmacodynamics that mediate heat stress, via the maintenance and control of the blood profile, osmotic pressure, gas concentration, and short chain fatty acid, of meat ducks under heat wave.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.857-864
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• 2012

Reviewing the statistics of harbor shipment of hazardous and noxious substance and the past spill accidents of HNS enabled us to assess the potential risks of transportation of HNS through the major harbors in Korea. Ulsan, Yeosu, Daesan port are relatively evaluated high risk in fire, health and environment disaster. Through the analysis of domestic preparedness to HNS accidents, the supplement of expertise resource to respond the vulnerability of the explosion, the fire and the physiological hazard, is required. Based on this risk assessment and review of the advanced case of Japan in building up HNS response system, a resource model at a national level was proposed which differentiates the sea areas for the proper allocation of resources to respond effectively to HNS accidents in the future.

• Journal of Korean Society of Transportation
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• v.30 no.3
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• pp.107-118
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• 2012

The purpose of the study is to analyze the travel characteristics of freight trucks in metropolitan areas, focusing on activity generation, destination choice, and trip chaining behaviors. The results showed that the number of service companies at departure areas has a primary influence on the activity generation pattern and destination choice behavior of trucks in metropolitan areas. The number of trips within a trip chain is largest, in case where the prevailing industry in destination areas is wholesale or retail and the shipment item is food or beverage. These results imply that for the reasonable estimation of truck travel demand both the trip chaining behaviors and the industrial compositions in departure and destination areas should be separately considered for each type of commodity.

• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.11-19
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• 2015

A certain number of products are transported to be sold each month and some of them are returned for repair. In this study we first assume that the transported products are the ones that have been sold, Then nonparametric approach is applied to the warranty returns data to see how the reliability decreases over time. Parametric approach such as Weibull distribution is applied to the same data and the results for both nonparametric and parametric approaches are compared. Next we assume that there is a time lag between shipment and sale. Then both nonparametric and parametric approaches are applied to the time-lag data and the results are compared.

• Journal of Navigation and Port Research
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• v.44 no.2
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• pp.128-135
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• 2020

Long-term shipping contracts represent the cooperative and coexisting relationships between the shipping and steel industries. Yet, differences between the contract forms for iron ore and steel products have emerged. Specifically, the large proportion of consecutive voyage charters (CVC) is being applied in the iron ore trade, whereas the contract of affreightment (COA) is proportionally higher for shipping steel products. The literature review and in-depth interviews in this study identified through the research model, the characteristics of the shipping and market structure in both markets have significantly contributed to the preference of different long-term contracts. It has been determined that the mutual oligopoly market structure and the characteristics of shipping such as, the small number of suitable vessels in the market, the single fixed load/discharge ports, the long-distance voyages, and the potential risks for fatal accidents because of cargo liquefaction, for the iron ore trade, provide higher contribution to the preference of CVC contracts. In contrast, the consignor oligopoly market structure and the shipping characteristics, such as the greater number of suitable vessels available in the market, the variation in ports, the cargo quantity per shipment, the various load/discharge ports, and the need for experienced carriers for steel product loading in the steel product trade has shown higher preference on the COA contracts as the consignors with superiority over the shipowners, resulting in favorable contract types and conditions for the consignors.

• Journal of the Korean Data and Information Science Society
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• v.28 no.3
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• pp.617-624
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• 2017

The production of cabbage, which is mainly cultivated in open field, varies greatly depending on weather conditions, and the price fluctuation is largely due to the presence of a substitute crop. Previous studies predicted the production of cabbage using actual weather data, but in this study, we predicted the wholesale price using unstructured agricultural meteorological data on the web. From January 2009 to October 2016, we collected documents including the cabbage on the portal site, and extracted keywords related to weather in the collected documents. We compared the forecast wholesale prices of simple models and unstructured agricultural weather models at the time of shipment. The simple model is AR model using only wholesale price, and the unstructured agricultural weather model is AR model using unstructured agricultural weather data additionally. As a result, the performance of unstructured agricultural weather model was has been found to be more accurate prediction ability.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1547-1550
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• 2015

Fuji apple variety introduced in Japan has excellent storage quality and good taste so it is most commonly cultivated in the Korean Peninsula. Accurate prediction of harvest maturity allows farmers to more efficiently manage their farm, such as working time, fruit storage, market shipment and labor distribution so it is very important. This study was carried out to predict the harvest maturity of 'Fuji' apple using DTS (Days Transformed to Standard temperature) model based on the Arrhenius law in the Gunwi province of the South Korea. Input data are daily average temperature and apple harvest maturity. Predicted the harvest maturity of Fuji apple after estimating the optimal parameters by using the Nelder-Mead method. The differences of observed and predicted harvest maturity day are approximately 1 to 4 days and the RMSE is 2.9.

• Korean journal of applied entomology
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• v.23 no.4 s.61
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• pp.242-246
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• 1984

Results obtained from the experiment conducted to find out e relationships between tuber decay, and water potential and bruising in or on the tubers, are summerized as follows ; 1) When potato tubers were bruised or injected with bacterial inoculum, the tubers with high water potential rotted more easily than the tubers with low potential. A big difference in the development of decay between high and low water potential tubers was found. 2) In tubers injected with different levels of inoculum. high water potential tubers were more susceptible to soft rot than low water potential tubers. 3) $ED_{50}$ of inoculum concentration was 8.5(log) at high water potential tubers and 9.8(log) at low water potential. A small difference between low and high water potential was detected. The results of this experiment show that potatoes should be handled carefully and must be dried after harvest to reduce decay development in shipment and storage.