• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.117-130
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• 2005

In both deteministic user Optimal Traffic Assignment Model (UOTAM) and stochastic UOTAM, travel time, which is a major ccriterion for traffic loading over transportation network, is defined by the sum of link travel time and turn delay at intersections. In this assignment method, drivers actual route perception processes and choice behaviors, which can become main explanatory factors, are not sufficiently considered: therefore may result in biased traffic loading. Even though there have been some efforts in Stochastic UOTAM for reflecting drivers' route perception cost by assuming cumulative distribution function of link travel time, it has not been fundamental fruitions, but some trials based on the unreasonable assumptions of Probit model of truncated travel time distribution function and Logit model of independency of inter-link congestion. The critical reason why deterministic UOTAM have not been able to reflect route perception cost is that the route perception cost has each different value according to each origin, destination, and path connection the origin and destination. Therefore in order to find the optimum route between OD pair, route enumeration problem that all routes connecting an OD pair must be compared is encountered, and it is the critical reason causing computational failure because uncountable number of path may be enumerated as the scale of transportation network become bigger. The purpose of this study is to propose a method to enable UOTAM to reflect route perception cost without route enumeration between an O-D pair. For this purpose, this study defines a link as a least definition of path. Thus since each link can be treated as a path, in two links searching process of the link label based optimum path algorithm, the route enumeration between OD pair can be reduced the scale of finding optimum path to all links. The computational burden of this method is no more than link label based optimum path algorithm. Each different perception cost is embedded as a quantitative value generated by comparing the sub-path from the origin to the searching link and the searched link.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.757-764
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• 2016

The purpose of this study was to investigate the salt and sodium content of lunch meals served at middle schools in Gyeongsangbuk-do. Four middle schools were investigated for their salt and sodium content and salt content contributing rate per meal. Average salt content of every lunch meal was 4.41 g, and average sodium content was 1,736.02 mg. During the investigation period, the lowest sodium content was 943.19 mg while the highest was 2,827.56 mg. Samples were classified into 16 food items and investigated for salt and sodium content. Total average salinity was 1.06%. Kimchi was the saltiest, followed by fresh-vegetables, boiled-vegetables, stir-fried foods, pan-fried foods, and hard-boiled foods. Total average salt content was 0.74 g, and most salty dishes were single dish rice noodles, followed by stews, steamed foods, broths, soups, kimchies, stir-fried foods, roasted foods, and hard-boiled foods. Samples were classified into seven menu groups, including cooked rice, single dish rice noodles, soup stew, main dish, side dish, kimchi, and desserts. Contributing rate of total average salt content was high in single dish rice noodles (40.56%), soup stew (23.23%), kimchies (20.30%), and main dish (18.13%). These results can be useful for establishing a database for sodium contents of meals in middle schools. 'SamSam foodservice' should be initiated in school foodservice to reduce sodium intake.