• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.1
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• pp.27-34
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• 2019

This paper presents a chamber pressure model development of K2 rifle by applying Gaussian mixture model. In order to materialize a real recoil force of a virtual reality shooting rifle in military combat training, the chamber pressure which is one of major components of the recoil force needs to be investigated and modeled. Over 200,000 data of the chamber pressure were collected by implementing live fire experiments with both K100 and M193 of 5.56 mm bullets. Gaussian mixture method was also applied to create a mathematical model that satisfies nonlinear, asymmetry, and deviations of the chamber pressure which is caused by irregular characteristics of propellant combustion. In addition, Polynomial and Fourier Regression were used for comparison of results, and the sum of squared errors, the coefficient of determination and root-mean-square errors were analyzed for performance measurement.

• Proceedings of the Korean Society for Environmental Edudation Conference
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• 2003.07a
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• pp.50-56
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• 2003

＃1 The Education from our Environment, The urgent subject for survival and prosperity in the future. - Around Yamaguchi in japan. - ＃2 Days of tour : January, 15, 2003 - January, 28, 2003 ＊ Comprehensive classes involved in ecosystems; Ryojo Elementary school, Guina Elementary school, Dabusei Junior High School, Ube Technical High School, Yashiro Elementary School, Toyota Nishi Junior High School, Seii Elementary School, Yamaguchi Prefectural School for the Mentally Impaired, Yamaguchi Institute for Educational Research and In-service Training, Kirara Beach Nature Watching Park ＃3 Characteristics of Yamaguchi Prefectural Environmental Education - Constant effort by concerned authorities and dedicated teachers - Cooperation of schools with community - Application of the comprehensive classes - Student-centered education through experiences - Acquirement of basic knowledge on environment in their daily lives - The harmony with the ability to survive' ＃4 Characteristics of the environmental education in each school $\square$ Ryojo Elementary School \longrightarrow Breeding the fireflies' larvae and releasing them into nature $\square$ Kuina Elementary School \longrightarrow Keeping the rivers clean $\square$ Yashiro Elementary School \longrightarrow Learning through exploring ‘Akiyoshido Cave’ $\square$ Seii Elementary School \longrightarrow Tree-planting campaign continued for 30 years $\square$ Tabuse Junior High School \longrightarrow Making their village good to live in $\square$ Toyota-Nishi Junior High School \longrightarrow Learning through working on the farm and in the forests $\square$ Ube Technical High School \longrightarrow Purifying the pond by the ‘biotope’ ＃5 Focus on Yashiro Elementary School \longrightarrow Children Guide Activity (25 hours annually) * To love their native place and tourists' attraction, Akiyoshidal * To introduce a variety of local events; - To make a fire in the mountains - To explore the cave - To hold a festival for tourists - To have a family-jointed bike riding ＃6 $\square$ conclusion - Gradual extension of environmental education * individuals \longrightarrow school \longrightarrow community - Finding the environmental problems around themselves and relating them with features of their community < Tips for the environmental education in the future > - Need for encouragement of more lively discussion in class - Expansive application of comprehensive classes to various areas

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.700-707
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• 2016

Recently, ammunition malfunctions of the 40mm grenade were reported during live fire training. When 72 40mm grenades were fired by the army, 11 duds were encountered. The dud ammunition rate was approximately 15%. Because ammunition is used a long time after its manufacture, it is necessary to ensure its performance after long-term storage. In this study, we attempted to decrease the dud ammunition rate of 40mm grenade (K200) fuzes through quality improvement. First, it was determined by the detonator performance test that abnormal explosions occurred due to the degradation of the detonator as a result of its aging characteristics. Second, we improved the fuze quality of the 40mm grenade. Third, we tested its shelf life to estimate its life expectancy. The shelf life of the 40mm grenade fuze obtained using the Arrhenius equation was 6.5 years for the existing grenade fuze and 45.5 years for the improved grenade fuze. This showed that the shelf life of the improved grenade was increased approximately 7 times. Therefore, the improved 40mm grenade fuze contributes to the quality improvement of the 40mm grenade by decreasing the dud ammunition rate during long term storage.