• Title/Summary/Keyword: sum of cross product

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Updating Sample Variance and Correlation Using Sum of Squares and Sum of Cross product (제곱합과 교차곱합의 특성을 이용한 표본분산과 상관계수의 계산)

  • Cho Tae-Kyoung;Shin Mi-Young
    • The Mathematical Education
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    • v.45 no.3 s.114
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    • pp.315-318
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    • 2006
  • In this paper we present the simple updating formulas for a sum of product and a sum of cross product when a new value is added on or a specific value is eliminated from the original data. The sample variance and correlation for the new data set are derived by new computing formulas. Any statistic which is a function of the sum of product and a sum of cross product also can be updated by proposed method even though the original data is not available.

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An Empirical Study on Customer-Oriented Quality Creation of Shoe : Focusing on Kano′s Model and QFD (제화의 고객지향적 품질창조에 관한 실증적 연구 - Kano의 모형과 QFD를 중심으로)

  • 김희탁;이종철
    • Journal of Korean Society for Quality Management
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    • v.30 no.1
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    • pp.1-21
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    • 2002
  • The purpose of this study was to empirically examine the customer oriented quality creation by considering quality elements required by customers in the product design process. The study tried to extract attractive quality elements by using Kano's model. After identifying the elements HOQ(the house of quality) of QFD(quality function deployment) was used to identify the trend of quality elements evaluation. Test for equal means (t-test) was applied to verify the attractive quality elements of adult shoes. It made us find the customer oriented quality elements from the customer needs and latent dissatisfaction. We collected the opinions of experts on shoes and complete the cause and effect diagram and affinity diagram (KJ method). The data of the questionnaire was put to the QFD and the contents of quality elements was identified by brain storming method. We calculated indexes which were the multiplication of weight and marks of quality elements in the cross table of the HOQ by QFD. Then we tested for the equality of means between the indexes and the sum of attractive quality elements. The results for equal means were statistically significant. To create the customer quality the product design should be differentiated between the age groups over attractive quality elements.

An Analysis for the Economic Impact of Forest Road Investment (임도시설 투자의 경제적 파급효과 분석)

  • Lee, Seung-Jung;Jung, Byung-Heon;Kim, Ki-Dong;Jeon, Hyon-Sun;Jo, Min-Woo
    • Journal of Korean Society of Forest Science
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    • v.106 no.2
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    • pp.219-229
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    • 2017
  • Forest road is an essential infrastructure for forest management such as the composition and management of forest resources, timber and forest byproduct production & transportation. It has recently been utilized forest recreation and forest sports as well as also forest pest control, forest fire prevention and evolution. When you build a forest road, the economic function in the forest is activated, so that it can result in the ripple effect of induced employment, value-added creation and production inducement. The purpose of this study is to analyze the impact caused by forest road construction occurring as the overall economy. For analysis it was applied to inter industry analysis method that is a method for analyzing the quantitative cross-correlation. The data were used in the Input-Output Tables In 2014, the Bank of Korea. When you build a forest road, economic effect due to the construction of the forest road is generated and economic effects are also generated due to the increase in the production of forest products after the construction of the forest road. Therefore, we will analyze the economic impact of the two effects. The estimated economic value of forest products, which is the economic effect of forest product cultivation, was calculated through some assumptions and the economic ripple effect was analyzed. The forest road construction sector is defined as land clearing and reclamation, and irrigation project construction and the forestry forest products sector is defined as the sum of raw timber, edible forest products and misc. forest products. In total, 32 sectors were classified, and except for the two sectors defined as forest road construction and forestry forest products, the remaining sectors were integrated according to the classification system of 30 integrated classifications of the Bank of Korea. As a result, the production inducement coefficient for forest construction was analyzed to be 2.767 and the production inducement coefficient for forestry forest products was analyzed to be 1.565. This means that 2,767 times the production of forest road construction investment is induced in the whole industry and the production of 1.562 times the amount of forestry forest products is caused by the whole industry as the production of forestry forest products increases. The value added inducement coefficient for forest road construction was 0.977 and the value added inducement coefficient for forestry forest products was 0.985. Forest road are essential infrastructure for forestry development and should be continuously invested because they are essential elements of timber production and forest byproduct production with functions such as forest management, forest recreation, forest sports, and town connection.