• 한국수산과학회지
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• 제48권2호
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• pp.168-177
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• 2015

Shell waste from the butter clam Saxidomus purpuratus and littleneck clam Ruditapes philippinarum is a large by-product of shellfish aquaculture, and it is desirable to convert it into value-added products for industrial applications. In this study, calcium carbonate (CaC) polymorphs from butter clam (BCSP) and littleneck clam (LCSP) shell powders and commercial CaC were characterized using Fourier transmission infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results revealed that the optimal calcination conditions to eliminate organic substances and improve solubility for both BCSP and LCSP were $800^{\circ}C$ for 8 h in an electrical furnace. Calcination improved the white index of the butter clam (BCCP) and littleneck clam (LCCP) calcined powder compared with shell powders. The calcium content in BCCP (51.1%) was higher than that of LCCP (44.9%) or commercial calcium oxide (CaO, 44.7%). The XRD patterns of BCCP and LCCP were similar to that of CaO. Cubic-like crystals of CaC and irregular crystals of BCCP and LCCP were observed by SEM. The FT-IR and XRD analyses revealed the presence of calcite and aragonite in the BCSP and aragonite in the LCSP, whereas the CaC contained calcite. These results indicate that butter and littleneck clam shells are potential biomass resources for calcium carbonate and calcium oxide.

• 품질경영학회지
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• 제52권2호
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• pp.275-286
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• 2024

Purpose: The spare part cost is one of the most important cost factors with which construct Life Cycle Cost. The LCSP(Life Cycle Sustainment Plan) Guidebook issued by Korea Ministry of Defense, however, suggests a simple equation to estimate the spare part cost using maintenance task frequencies and each part cost. Therefore, following the cost estimation method in the LCSP Guidebook may lead to an improper cost estimation result since both the hierarchical structure of the weapon system and the part discard rate are not considered. The purpose of this study is to develop a new life cycle cost estimation method for spare parts of weapon system during its life cycle. Methods: In this study, the detailed cost structure of spare parts is provided. Also a new spare part cost estimation methods for the each cost element are proposed, considering the hierarchical structure of weapon system and the part discard rate. And the proposed spare cost estimation methods are applied to K system for a case study. Results: Based on the case study of K system, the spare part cost estimation method, proposed by this study, shows that it can complement the estimation method suggested by the LCSP Guidebook. It also shows that it is applicable to the weapon systems for Korea armed forces. Conclusion: The proposed life cycle cost estimation method for spare parts has an advantage of estimating the spare part cost more accurately. It is expected to be useful in analyzing the procurement alternatives objectively and making up the Korea armed forces budget effectively.

• 한국산학기술학회논문지
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• 제21권12호
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• pp.417-425
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• 2020

최근의 무기체계 개발은 4차 산업 혁명과 연계하여 민간 상용기술의 우위 분야를 적극적으로 접목시켜 개별 상용 시스템들을 통합(SI) 개발하는 추세이다. 그러나, 이러한 상용품 기반 무기체계의 경우 소요 제안요청서(RFP)에 기술교범국방규격서를 적용한 기술교범 개발, 군직 야전정비용 지원장비, 전자식 기술교범(IETM), 전자식 교보재(CBT) 개발과 무기체계 RAM 목표값 및 국방규격품 수준의 군수지원분석(LSA) 등 전 분야에 걸친 ILS 요소개발이 요청되어 개발업체의 제안 범위의 현실성이 떨어지고 이와 연계된 개발을 소요 대비 과도하게 진행하고 있는 실정이다. 상용품 기반 SI 무기체계는 외주정비 시행의 기본 틀에서 소요군에 반드시 필요한 핵심요소로 한정시킨 ILS 개발과 PLS 방향 설정에 역점을 둔 소요요청서(RFP)와 계약 방식이 적용되어야 군과 개발업체 상호 보완 및 효과적인 운영유지를 위한 종합군수지원을 완성할 수 있을 것이다. 따라서 현 무기체계 운용실태 확인을 통해 상용품 기반 무기체계의 군수지원은 외주화를 기본 정책으로 선정하여 합리적 의사결정 과정을 통해 운영유지에 중점을 둔 개발 필요 요소를 결정하고 결정된 핵심요소에 대한 개발방안을 RFP에 적용하는 방안과 PLS를 위한 방안에 대해 본 논문에 제시하였다.