• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.1-13
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• 2022

Household refrigerator cabinets must undergo cyclic testing at -20 ℃ and 65 ℃ for quality control (QC) after their production is complete. These cabinets were assembled from different materials, including acrylonitrile butadiene styrene (ABS), polyurethane (PU) foam, and steel plates. However, different thermal expansion values could be observed owing to differences in the mechanical properties of the materials. In this study, a technique to predict delamination on a refrigerator wall caused by thermal deformation was developed. The mechanical properties of ABS and PU foams were tested, theload factors causing delamination were analyzed, delamination was observed using a high-speed camera, and comparison and verification in terms of stress and strain were performed using a finite element model (FEM). The results indicated that the delamination phenomenon of a refrigerator wall can be defined in two cases. A method for predicting and evaluating delamination was established and applied in an actual refrigerator. To determine the effect of temperature changes on the refrigerator, strain measurements were performed at the weak point and the stress was calculated. The results showed that the proposed FEM prediction technique can be used as a basis for virtual testing to replace future QC testing, thus saving time and cost.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.663-668
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• 2022

As the number of people who experience sleep disorders is increasily growing, users' desire to improve their sleep quality has also increased. Acoordingly, the 'Sleeptech' market is showing a steady growth. This study designs and proposes a system after consideration of existing related research that can help modern people overcome sleep disorders, which is based on the necessity for customized sleep hygien service. This system analyzes user's sleep data collected through smartphone built-in sensors to calculate sleep patterns, provides customized sleep hygiene-based solutions to users through collaborative filtering, and provides an environment suitable for sleep through the automatic control of IoT devices. This method of using sleep data is expected to contribute to the improvement of the quality of life of modern people suffering from sleep disorders, which results from expansion to Sleeptech market as well as improvement of users' sleep habits.

• Analyses & Alternatives
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• v.6 no.2
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• pp.5-36
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• 2022

The Russia-Ukraine War was a "three-layer compounded war" between the US and Russia, Russia and Ukraine, and Ukrainian government forces and rebels. First, the war is a phenomenon that occurred when the western sphere of influence seeking to maintain and strengthen the liberal international order and the Sino-Russian sphere of influence seeking a new alternative order collided in Ukraine, a geopolitical fault zone. Second, this war is the result of a typical 'security dilemma' phenomenon caused by the 'chain reaction' game of NATO's continuous expansion and Russia's response. Third, the Russia-Ukraine war was caused by the Russian military projection to prevent the military restoration of Donbas region by Ukraine. Until now, the Western world, led by the US, showed unexpected solidarity after the war despite subtle differences in positions. However, the non-Western world, including China, is not participating in the condemnation and sanctions against Russia. This war will be an important turning point in the existence and change of the current international order that has been formed and is operating since the end of the Cold War. The direction of maintenance/restoration, revision/change, and end/transformation of the current international order is highly likely to be determined depending on the development pattern and method of ending the war.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.2
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• pp.61-68
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• 2023

Ti and Ti alloys are used in the automobile and aerospace industries due to their high specific strength and excellent corrosion resistance. However their application is limited due to poor formability at room temperature and high unit cost. In order to overcome these issues, dissimilarly jointed materials, such as cladding materials, are widely investigated to utilize them in each industrial field because of an enhanced plasticity and relatively low cost. Among various dissimilar bonding processes, the rolled cladding process is widely used in Ti alloys, but has a disadvantage of low bonding strength. Although this problem can be solved through post-heat treatment, the mechanical properties at the bonded interface are deteriorated due to residual stress generated during post-heat treatment. Therefore, in this study, the microstructure change and residual stress trends at the interfaces of Ti/Al cladding materials were studied with increasing post-heat treatment temperature. As a result, compared to the as-rolled specimens, no difference in microstructure was observed in the specimens after postheat treatment at 300, 400, and 500℃. However, a new intermetallic compound layer was formed between Ti and Al when post-heat treatment was performed at a temperature of 600℃ or higher. Then, it was also confirmed that compressive residual stress with a large deviation was formed in Ti due to the difference in thermal expansion coefficient and modulus of elasticity between Ti Grade II and Al 1050.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.150-156
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• 2022

As the 4th industrial revolution emerges, the implementation of smart factories are essential in the manufacturing industry. However, 80% of small and medium-sized enterprises that have introduced smart factories remain at the basic level. In addition, in root industries such as injection molding, PLC and HMI software are used to implement functions that simply show operation data aggregated by facilities in real time. This has limitations for managers to make decisions related to product production other than viewing data. This study presents a method for upgrading the level of smart factories to suit the reality of small and medium-sized enterprises. By monitoring the data collected from the facility, it is possible to determine whether there is an abnormal situation by proposing an appropriate algorithm for meaningful decision-making, and an alarm sounds when the process is out of control. In this study, the function of HMI has been expanded to check the failure frequency rate, facility time operation rate, average time between failures, and average time between failures based on facility operation signals. For the injection molding industry, an HMI prototype including the extended function proposed in this study was implemented. This is expected to provide a foundation for SMEs that do not have sufficient IT capabilities to advance to the middle level of smart factories without making large investments.

• Korean Journal of Culture and Social Issue
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• v.17 no.4
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• pp.365-380
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• 2011

This study was conducted to examine whether hasty behaviors were structurally maintained even after the expansion of age zones and to determine the characteristics of hasty behaviors by gender and age. To this end, an analysis was made of the data of 591 respondents after excluding the insincere respondents from the 602 adults who had replied to the survey on hasty behaviors. Its results showed that a hasty behavior consisted of 5 factors regardless of age. Even when age was expanded, a hasty behavior maintained its structural stability. On the other hand, women were higher than men in the average score of hasty behaviors. Lastly, hasty behaviors decreased with the increase in age. The gender differences in hasty behaviors were analyzed on the basis of those in time pressure perception and task processing method. They were presented to show that the speed reduction by age increase is related to psychological mechanism as well as bodily function.

• Journal of Fashion Business
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• v.27 no.4
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• pp.141-162
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• 2023

With the prospect that integrating creative AI in the fashion design field will become more visible, this study considered the case of creative fashion design development through Human-AI Co-creation (HAIC). Methodologically, this research encompasses a literature review and empirical investigations. In the literature review, the fashion design and creative HAIC processes, and the possibilities of integrating AI in fashion design were considered. In the empirical study, based on the case analysis of generating fashion design through HAIC, the HAIC type according to the role and interaction method, and characteristics of humans and AI was considered, and the HAIC process for fashion design was derived. The results of this study are summarized as follows. First, HAIC types in fashion design are divided into four types: AI-driven passive HAIC, human-driven passive HAIC, flexible interaction-based HAIC, and integrated interaction-based value creation HAIC. Second, the stages of the HAIC process for creative fashion design can be broadly divided into semantic data integration, visual ideation, design creation and expansion, design presentation, and design/manufacturing solution and UX platform creation. Third, in fashion design, HAIC contributes to human ability, enhancement of creativity, achievement of efficient workflow, and creation of new values. This research suggests that HAIC has the potential to revolutionize the fashion design industry by facilitating collaboration between humans and AI; consequently, enhancing creativity, and improving the efficiency of the design process. It also offers a framework for understanding the different types of HAIC and the stages involved in the creative fashion design process.

• Korean Journal of Materials Research
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• v.32 no.12
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• pp.545-552
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• 2022

Tin-antimony sulfide nanocomposites were prepared via hydrothermal synthesis and a N₂ reduction process for use as a negative electrode in a sodium ion battery. The electrochemical energy storage performance of the battery was analyzed according to the tin-antimony composition. The optimized sulfides exhibited superior charge/discharge capacity (770 mAh g^-1 at a current density of 100 mA g^-1) and stable lifespan characteristics (71.2 % after 200 cycles at a current density of 500 mA g^-1). It exhibited a reversible characteristic, continuously participating in the charge-discharge process. The improved electrochemical energy storage performance and cycle stability was attributed to the small particle size, by controlling the composition of the tin-antimony sulfide. By optimizing the tin-antimony ratio during the synthesis process, it did not deviate from the solubility limit. Graphene oxide also acts to suppress volume expansion during reversible electrochemical reaction. Based on these results, tin-antimony sulfide is considered a promising anode material for a sodium ion battery used as a medium-to-large energy storage source.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.761-768
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• 2022

In the hope of realizing carbon neutrality, Korea has established the goal of expanding the supply of hydrogen electric vehicles through a roadmap to revitalize the hydrogen economy. A prerequisite for successful supply expansion is securing the safety of hydrogen electric vehicles. Certain parts, such as the hydrogen transport pipe and tank, in hydrogen electric vehicles are exposed to high-pressure hydrogen gas over long periods of time, so the hydrogen enters the grain boundary of material, resulting in a degradation of the parts referred to as hydrogen embrittlement. In addition, since the safety of parts utilizing hydrogen varies depending on the type of material used and its environmental characteristics, the necessity for the enactment of a hydrogen embrittlement regulation has emerged and is still being discussed as a Global Technical Regulation (GTR). In this paper, we analyze a hydrogen compatibility material evaluation method discussed in GTR and present a direction for the development of Korean-type hydrogen compatibility material evaluation methods.

• Quality Improvement in Health Care
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• v.28 no.2
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• pp.14-29
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• 2022

Purpose:In order to improve the quality of cardiac rehabilitation, it is important to examine the experiences of the patients and how they feel about each part of the process. We used a qualitative research methodology to conduct an in-depth review of the experiences of patients who participated in cardiac rehabilitation. Methods: According to semi-structured guidelines, in-depth interviews were conducted with a total of five patients undergoing cardiac rehabilitation. Results: A total of 232 codes was derived; these codes were split into 4 categories and 10 subcategories. Although the patients were apprehensive about the diagnosis of heart disease, it also gave them a chance to reflect on their health behaviors of the past. In addition, they began to appreciate their families and support networks more as the disease progressed. The participants did not know about cardiac rehabilitation until the medical staff recommended it, but they participated in the program with the expectation that they could become healthier. The participants felt that they became more physically and mentally healthy while undergoing cardiac rehabilitation. Rehabilitation served as an opportunity to improve other health behaviors as well. However, they emphasized that it is necessary to continuously maintain improved health behavior, find an exercise method that is suitable for one's physical ability and not monotonous, and prepare a plan to reduce the time and economic burden of cardiac rehabilitation. Conclusion: The participants' positive experiences confirmed in this study will be used as evidence for the expansion of cardiac rehabilitation programs.