• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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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.

• Journal of Powder Materials
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• v.28 no.1
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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%.

• Journal of Powder Materials
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• v.28 no.3
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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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• v.35 no.1
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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.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.213-217
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• 2022

It is a time when a sustainable Korean Culture Festival strategy is needed. The Korean Culture Festival is a Hallyu Culture Festival that comprehensively introduces various Korean cultures such as Korean food, beauty, and fashion with the focus on K content, which has been leading the global craze since 2020. As the core project of the promotion of Neo Hallyu by the Ministry of Culture and Gymnasium, the 2021 Korean Culture Festival, which was based on the World K-Pop concert and the K-Culture Fan Fair, including holding the first face-to-face concert that applied the stage of real-world content after Covid-19, as well as conducting and exhibiting various fan participation challenges, must now make the leap to the global Hallyu Culture Festival. To this end, it can consist of drama, K-pop, K-Culture Fan Fair, K-Meetup, K-Culture Parade, and Awards. This distinction shows a classic festival program centered around the prosumer content that drives the Korean Wave, and in order for this philosophy to be effectively linked to its contemporaries, a Business to Business (B2B) and Business to Consumer (B2C) 'Techtainment Strategy' is needed to acquire potential customers through learned playfulness.

• Food Science of Animal Resources
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• v.42 no.4
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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.

• Food Science of Animal Resources
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• v.42 no.1
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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.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.33 no.3
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• pp.55-76
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• 2022

The 3rd Library Development Plan raises the need to secure space through the establishment of a regional repository library as the issue of holding books is highlighted as a common problem in public libraries. The Korean Library Law Act also impose the responsibility of integrated management of local library materials on the regional representative library. Accordingly, this study aimed at Busan Metropolitan Library, which is operating a collaborative repository in earnest among regional representative libraries, and investigated the operation status of the collaborative repository and the perception of public librarians about the collaborative repository. The data necessary for the study were obtained through surveys, interviews, field surveys, and internal data analysis. Through this, the purpose of this study was to provide basic data that will help the Busan Metropolitan Library to operate the collaborative repository efficiently in the future, and at the same time, to present basic data that can be used as a reference for the operation of the collaborative repository of the representative libraries of other regions.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.5
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• pp.52-62
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• 2022

A launch vehicle is a one of the biggest hardware among the products of human technology. For huge size launch vehicles, to transport to Launch Complex and to erect on launch pad precisely and safely is very critical issue. Therefore, a final assembly, transportation, erection and holding in vertical position in launch pad requires very precise operational technology, processes and related aggregates. Those operational concept has been developed to comply with the requirement of each launch vehicle and technology level at that time. In this paper, a progress of operational methodology in global launch vehicles are described. In addition, methodologies used on the KSLV-1 Naro and the KSLV-II Nuri launch vehicle are introduced.

• Journal of Korean Society for Quality Management
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• v.50 no.1
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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.