About 50,000 hives of Bombus terrestris are used for pollination of tomato and other economical crops (fruit vegetables and fruit trees) in Korea. Therefore this study was conducted to find out the effective use of B. terrestris and its economic effect in the major beefsteak-tomato cultivation areas from February to August in 2008. The pollinating activities, rate of bite-mark and lifespan of B. terrestris"s hive according to all beefsteak-tomato varieties (Super Momotaro, Zeus42, Mascara and Super Sunroad, 500 ㎡, 9,600～12,000plants) were apparent by regular supplement of pollen (5～6g/3 days) to the hive of B. terrestris. Especially, Super Momotaro and Super Sunroad variety were most distinctive in the effects by regular pollen supplement.

This study determined the ship replacement life expectancy from an economic perspective. There are many ambiguities in the cost for calculation of economic lifespan, and these were expressed as fuzzy numbers. Also, a fuzzy cost model using fuzzy numbers was developed and suggested as a more practical analysis method than the existing cost model. And the suggested fuzzy model was used to determine the economic lifespan for various types of container ships. As the result, Without fuzziness, the economic lifespan of 5000 TEU Ships was found to be 19 years. it was found that the greater the container ship, the greater the economic lifespan was.