• 산업경영시스템학회지
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• 제44권2호
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• pp.24-35
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• 2021

Due to increasing awareness on the treatment of end-of-use/life products, disassembly has been a fast-growing research area of interest for many researchers over recent decades. This paper introduces a novel lot-sizing problem that has not been studied in the literature, which is the service-parts lot-sizing with disassembly option. The disassembly option implies that the demands of service parts can be fulfilled by newly manufactured parts, but also by disassembled parts. The disassembled parts are the ones recovered after the disassembly of end-of-use/life products. The objective of the considered problem is to maximize the total profit, i.e., the revenue of selling the service parts minus the total cost of the fixed setup, production, disassembly, inventory holding, and disposal over a planning horizon. This paper proves that the single-period version of the considered problem is NP-hard and suggests a heuristic by combining a simulated annealing algorithm and a linear-programming relaxation. Computational experiment results show that the heuristic generates near-optimal solutions within reasonable computation time, which implies that the heuristic is a viable optimization tool for the service parts inventory management. In addition, sensitivity analyses indicate that deciding an appropriate price of disassembled parts and an appropriate collection amount of EOLs are very important for sustainable service parts systems.

• 한국분말재료학회지
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• 제28권1호
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• pp.51-58
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• 2021

The conversion of carbon preforms to dense SiC by liquid infiltration is a prospectively low-cost and reliable method of forming SiC-Si composites with complex shapes and high densities. Si powder was coated on top of a 2.0wt.% Y2O3-added carbon preform, and reaction bonded silicon carbide (RBSC) was prepared by infiltrating molten Si at 1,450℃ for 1-8 h. Reactive sintering of the Y2O3-free carbon preform caused Si to be pushed to one side, thereby forming cracking defects. However, when prepared from the Y2O3-added carbon preform, a SiC-Si composite in which Si is homogeneously distributed in the SiC matrix without cracking can be produced. Using the Si + C → SiC reaction at 1,450℃, 3C and 6H SiC phases, crystalline Si, and Y2O3 were generated based on XRD analysis, without the appearance of graphite. The RBSC prepared from the Y2O3-added carbon preform was densified by increasing the density and decreasing the porosity as the holding time increased at 1,450℃. Dense RBSC, which was reaction sintered at 1,450℃ for 4 h from the 2.0wt.% Y2O3-added carbon preform, had an apparent porosity of 0.11% and a relative density of 96.8%.

• 한국분말재료학회지
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• 제28권3호
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• pp.221-226
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• 2021

We fabricate the non-equiatomic high-entropy alloy (NE-HEA) Fe_49.5Mn₃₀Co₁₀Cr₁₀C_0.5 (at.%) using spark plasma sintering under various sintering conditions. Each elemental pure powder is milled by high-energy ball milling to prepare NE-HEA powder. The microstructure and mechanical properties of the sintered samples are investigated using various methods. We use the X-ray diffraction (XRD) method to investigate the microstructural characteristics. Quantitative phase analysis is performed by direct comparison of the XRD results. A tensile test is used to compare the mechanical properties of small samples. Next, electron backscatter diffraction analysis is performed to analyze the phase fraction, and the results are compared to those of XRD analysis. By combining different sintering durations and temperature conditions, we attempt to identify suitable spark plasma sintering conditions that yield mechanical properties comparable with previously reported values. The samples sintered at 900 and 1000℃ with no holding time have a tensile strength of over 1000 MPa.

• Animal Bioscience
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• 제35권1호
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• pp.96-104
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• 2022

Objective: Sarcoplasmic proteins include proteins that play critical roles in biological processes of living organisms. How seasons influence biological processes and meat quality of postmortem muscles through the regulation of protein phosphorylation remain to be investigated. In this study, the phosphorylation of sarcoplasmic proteins in pork longissimus muscle was investigated in four seasons. Methods: Sarcoplasmic proteins were extracted from 40 pork carcasses (10 for each season) and analyzed through ProQ Diamond staining for phosphorylation labeling and Sypro Ruby staining for total protein labeling. The pH of muscle, contents of glycogen and ATP were measured at 45 min, 3 h, and 9 h postmortem and the water (P_2b, P₂₁, and P₂₂) was measured at 3 h and 9 h. Results: A total of 21 bands were detected. Band 8 (heat shock cognate 71 kDa protein; heat shock 70 kDa protein 1B) had higher phosphorylation level in summer than that in other seasons at 45 min postmortem. The phosphorylation levels of 3 Bands were significantly different between fast and normal pH decline groups (p<0.05). The phosphorylation levels of 4 bands showed negative associations with immobilized water (P₂₁) and positive association with free water (P₂₂). Conclusion: The phosphorylation levels of sarcoplasmic proteins involved in energy metabolism and heat stress response at early postmortem time differed depending on the seasons. These proteins include heat shock protein 70, pyruvate kinase, phosphoglucomutase-1, glucose-6-phosphate isomerase, and carbonic anhydrase 3. High temperatures in summer might result in the phosphorylation of those proteins, leading to pH decline and low water holding capacity.

• 문화기술의 융합
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• 제8권4호
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• pp.213-217
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• 2022

지속가능한 한국문화축제 전략이 필요한 시기다. 한국문화축제는 2020년부터 전 세계적인 열풍을 이끌고 있는 K 콘텐츠를 중심으로 한식, 뷰티, 패션 등 다양한 한국문화를 종합적으로 소개하는 한류문화축제다. 문화체육관광부 신한류 진흥 핵심사업으로써 코로나 이후 실감 콘텐츠 무대를 적용한 첫 대면 콘서트 개최를 비롯하여 다양한 팬 참여 챌린지 진행 및 전시 등 월드 케이팝 콘서트와 K컬쳐 팬 페어를 바탕으로 했던 2021년 한국문화 축제는 이제 글로벌 한류 문화 축제로 도약해야 한다. 이를 위해서 드라마, 케이팝, K컬처 팬 페어, K밋업, K컬처 퍼레이드, 어워즈로 구성될 수 있다. 이러한 구분은 한류를 이끄는 프로슈머적 콘텐츠를 중심으로 고전적인 축제 프로그램을 보여주는데 이러한 철학이 동시대에 효율적으로 연계되기 위해서 학습된 유희성을 통해 잠재적 고객 확보를 위한 Business to Business(B2B), Businesss to Consumer(B2C) 테크테인먼트(Techtainment) 전략이 필요하다.

• 한국축산식품학회지
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• 제42권4호
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• pp.557-565
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• 2022

The purpose of this research was to examine the effectiveness of pre-cooking treatments on the quality characteristics of ready-to-eat (RTE) empal gentong. Raw beef meat was pre-cooked in water bath at 90℃ for 0 min (C), 10 min (T1), 20 min (T2), and 30 min (T3) prior to retorting process at 121℃ and pressure at 70,000 Pa. Results showed that pre-cooking treatments in all treated samples could reduce fat contents in empal gentong's meat by 0.02% (T1), 0.28% (T2), and 1.13% (T3) respectively. Highest precooking time tends to increase the pH and CIE a^* values. However, CIE b^* values, water holding capacity, and sensory analysis were not affected by pre-cooking duration which must have been affected by sterilization process after pre-cooking. In conclusion, pre-cooking treatment before sterilization in producing empal gentong is a probable technique to reduce its fat content and improve its physical quality. A specific treatment at 90℃ for 10 min is recommended to achieve optimum quality of RTE empal gentong's meat.

• 한국축산식품학회지
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• 제42권1호
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• pp.61-72
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• 2022

Antioxidants present in fruits and vegetables have a potential to reduce disease risk, and increase the shelf life of food products by reducing lipid oxidation. The effect of marination with antioxidants-rich fruit juices on quality characteristics of vacuum-packed chicken wings were examined during frozen storage. Chicken wings were mixed separately with marinades containing pineapple juice, June plum juice, and mango juice and kept for 12 h and 24 h. Three best marination conditions were selected based on a sensory evaluation. Antioxidant activity and total phenolic content of fruit juices, and marinade uptake, and marinade loss of marinated chicken wings were determined. In addition, vacuum packed marinated chicken wings were tested for pH, water holding capacity (WHC), 2-thiobarbituric acid reactive substances (TBARS) value and antioxidant activity over a 4-wk frozen storage. The best sensory properties were reported from chicken wings marinated with pineapple juice for 24 h, mango juice for 24 h, and June plum juice for 12 h (p<0.05) compared to other marinade-time combinations. Mango juice showed the highest antioxidant activity (92.2%) and total phenolic content (38.45 ㎍/mL; p<0.05) compared to other fruit juices. The pH and WHC of vacuumpacked chicken wings were slightly decreased over the frozen storage (p<0.05). Moreover, chicken wings marinated with mango juice had the lowest TBARS values and the highest 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging activity. In conclusion, mango juice was selected among tested as the most effective marinade for enhancing the oxidative stability of lipid while maintaining the other meat quality traits of vacuum-packed chicken wings.

• 한국비블리아학회지
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• 제33권3호
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• pp.55-76
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• 2022

「제3차 도서관발전종합계획」에서는 공공도서관의 공통적인 문제로 장서수장문제가 부각됨에 따라 지역 단위 공동보존서고 설치를 통한 공간확보의 필요성을 제기하고 있다. 「도서관법」 및 「도서관법시행령」 역시 지역 도서관 자료에 대한 통합적 관리의 책임을 지역대표도서관에 부과하고 있다. 이에 이 연구는 지역대표도서관 중 본격적으로 공동보존서고를 운영하고 있는 부산도서관을 연구대상으로 하여 공동보존서고의 운영현황과 공동보존서고에 대한 관내 공공도서관 사서의 인식을 조사하였다. 연구에 필요한 데이터는 설문조사와 인터뷰, 현장조사, 내부자료 분석 등을 통하여 입수하였다. 이를 통해 향후 부산도서관 공동보존서고를 효율적으로 운영할 수 있는데 도움이 되는 기초적인 데이터를 제공함과 동시에 타지역 대표도서관 공동보존서고 운영에 참고할 만한 기초자료를 제시하는 것을 연구의 목적으로 하였다.

• 한국추진공학회지
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• 제26권5호
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• pp.52-62
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• 2022

우주발사체는 가장 거대한 시스템 중의 하나로, 이처럼 장대한 발사체를 발사운용시 안전하고 신속하게 발사대로 이송하고 발사자세인 수직상태로 전환하는 것은 매우 중요한 요소이다. 이에따라, 발사체를 전기체로 총조립하고 발사대에서 발사자세인 수직자세로 만들기위한 과정은 매우 정밀한 운용방법, 절차 및 관련장치들을 필요로 한다. 이러한 이송 기립 운용 개념은 세계 각국의 우주 발사체 개발 과정 중 각각의 요구조건 및 당시의 기술수준에 맞도록 발전되어 왔다. 본 논문에서는 세계 발사체들의 이송 기립 운용 개념을 소개하고 한국의 나로호 및 누리호의 운용개념에 대해 소개한다.

• 품질경영학회지
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• 제50권1호
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• pp.153-167
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• 2022

Purpose: The purpose of this study is to guide the operation managers who plan daily production of large mass-processing facility that services multi-customers with multi-product, small-batch item characteristics by providing the practical best production quantity and the inventory allowed to build. Methods: Close observation of a subcontract paint-shop operator captured the daily decision process which was reflected in the subcontractor-unique mathematical model and the system dynamics simulation model. Multiple simulations were run to find the practical best production quantity and the maximum allowable stock level of inventory that did not undermine the profit from practical best daily production. Actual data and a few constant values were obtained from the firm under study. Results: While the inventory holding cost for the customer-owned material harms the total profit of the subcontractor, the running cost of the processing facility hinders production in small batches. This balances the maximum possible productions and results in practical best daily production which can be found through simulation runs with actual data. The maximum level of stocked inventory is deduced from the practical best daily production. Conclusion: To build a large volume that enables economy-of-scale production, operators should deal with multi-product small-batch items from multiple customers. When the planned schedule of the time and amount of material in-flow tend not to be reliable, operators can find it practical to execute level production across the planning horizon instead of adjusting to day-to-day in-flow fluctuations.