• Journal of Korea Society of Industrial Information Systems
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• v.27 no.3
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• pp.29-46
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• 2022

COVID-19 has radically changed the behavior of members of society for exchange. In particular, the strong contagiousness of the virus is increasing networking on online platforms while reducing people's networking in the real world. Recently, the metaverse, which strengthened the presence based on 3D technology, is attracting attention from members of society such as individuals and companies. We present a method to improve metaverse utilization from the perspective of organizations and employees who have introduced metaverse for work. In other words, we check the effect of metaverse social function and telepresence on the employee's intention to offer support by improving the trust of the metaverse participants. We obtained samples through questionnaires targeting employees of organizations that introduced metaverse to their work, and verified the research hypothesis by applying the structural equation model. As a result, social interactivity, reciprocal favor, and telepresence of metaverse partially affected metaverse trust (platform, peer, organization), and metaverse trust increased the intention to offer support. Our study suggests a strategic direction to improve the metaverse utilization and exchange level of employees of organizations who want to use the metaverse for business.

• The Journal of Engineering Geology
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• v.32 no.3
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• pp.377-388
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• 2022

Recently, several studies have utilized machine learning to efficiently and accurately analyze seismic data that are exponentially increasing. In this study, we expand earthquake information such as occurrence time, hypocentral location, and magnitude to produce a dataset for applying to machine learning, reducing the dimension of the expended data into dominant features through principal component analysis. The dimensional extended data comprises statistics of the earthquake information from the Global Centroid Moment Tensor catalog containing 36,699 seismic events. We perform data preprocessing using standard and max-min scaling and extract dominant features with principal components analysis from the scaled dataset. The scaling methods significantly reduced the deviation of feature values caused by different units. Among them, the standard scaling method transforms the median of each feature with a smaller deviation than other scaling methods. The six principal components extracted from the non-scaled dataset explain 99% of the original data. The sixteen principal components from the datasets, which are applied with standardization or max-min scaling, reconstruct 98% of the original datasets. These results indicate that more principal components are needed to preserve original data information with even distributed feature values. We propose a data processing method for efficient and accurate machine learning model to analyze the relationship between seismic data and seismic behavior.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.5
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• pp.355-374
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• 2022

Soil conditioning improves the performance of EPB (earth pressure balance) shield TBMs (tunnel boring machines) by reducing shear strength, enhancing workability of the excavated soil, and supporting the tunnel face during EPB tunnelling. The mechanical and rheological behavior of the excavated muck mixed with additives should be properly evaluated to determine the optimal additive injection condition corresponding to each ground type. In this study, the laboratory pressurized vane test apparatus equipped with a vane-shaped rheometer was developed to reproduce the pressurized condition in the TBM chamber and quantitively evaluate rheological properties of the soil specimens. A series of the pressurized vane tests were performed for an artificial sand soil by changing foam injection ratio (FIR) and polymer injection ratio (PIR), which are the injection parameters of the foam and the polymer, respectively. In addition, the workability of the conditioned soil was evaluated through the slump test. The peak and yield stresses of the conditioned soil with respect to the injection parameters were evaluated through the rheogram, which was derived from the measured torque data in the pressurized vane test. As FIR increased or PIR decreased, the workability of the conditioned soil increased, and the maximum torque, peak stress, and yield stress decreased. The peak stress and yield stress of the specimen from the laboratory pressurized vane test correspond to the workability evaluated by the slump tests, which implies the applicability of the proposed test for evaluating the rheological properties of excavated soil.

• Resources Recycling
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• v.31 no.2
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• pp.12-19
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• 2022

The study was conducted to develop a vanadium recovery process using reduction pre-treatment in the Vanadium TitanoMagnetite (VTM) The sample for the research was provided by the Gwan-in Mine in Pocheon, Gyeonggi-do. The vanadium content of the sample is 0.54 V₂O₅% and vanadium is concentrated mainly in magnetite and ilmenite. Magnetic separation of the sample can increase vanadium content up to 1.10 V₂O₅%. To increase the vanadium content further, reduction pre-treatment was performed, which is a process of concentrating vanadium present in the iron by reducing iron in magnetite using carbon(C). Based on this reduction pre-treatment, the magnetic separation process was developed, which achieved a vanadium grade of 1.31V₂O₅% and 79.68% recovery. In addition, XRD analysis of the vanadium concentrate before and after reduction and the final vanadium concentrate was performed to confirm the behavior of vanadium by reduction pre-treatment.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.105-111
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• 2023

Electronic devices have been evolved to be mechanically flexible that can be endured repetitive deformation. This evolution emphasizes the importance of long-term reliability in metal wiring connecting electronic components, especially under bending fatigue in compressed environments. This study investigated methods to enhance adhesion between copper (Cu) and polyimide (PI) substrates, aiming to improve the reliability of copper wiring under such conditions. We applied oxygen plasma treatment and introduced a chromium (Cr) adhesion layer to the polyimide substrate. Our findings revealed that these adhesion enhancement methods significantly affect compression fatigue behavior. Notably, the chromium adhesion layer, while showing weaker fatigue characteristics at 1.5% strain, demonstrated superior performance at 2.0% strain with no delamination, outperforming other methods. These results offer valuable insights for improving the reliability of flexible electronic devices, including reducing crack occurrence and enhancing fatigue resistance in their typical usage environments.

• Journal of The Korean Society of Clinical Toxicology
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• v.21 no.2
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• pp.69-80
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• 2023

Purpose: Suicide ranks among the top causes of death among youth in South Korea. This study aimed to identify the characteristics of suicidal individuals treated at emergency departments between 2011 and 2020. Methods: A retrospective analysis was conducted using data from January 2011 to December 2020 in the Injury Surveillance Cohort, a prospective registry. Patients' sex, age, mortality, methods of self-harm, and previous suicide attempts were analyzed. The methods of self-harm were categorized into falls, asphyxiation, blunt injuries, penetrating injuries, poisoning, and others. Sub-groups with and without poisoning were compared. Results: The proportion of self-harm/suicide attempts increased from 2.3% (2011) to 5.0% (2020). The mortality rate decreased from 10.8% (2011) to 6.3% (2020). Poisoning was the most common method (61.7%). Mortality rates ranged from 42.0% for asphyxiation to 0.2% for blunt injuries. Individuals in their 20s showed a marked increase in suicide/self-harm attempts, especially in the last three years. A large proportion of decedents in their 70s or older (52.6%) used poisoning as a method of suicide. The percentage of individuals with two or more previous attempts rose from 7.1% (2011) to 19.7% (2020). The death rates by poisoning decreased from 7.7% (2011) to 2.5% (2020). Conclusion: Our findings underscore the urgent need for targeted interventions and suicide prevention policies. Managing and reducing suicide and self-harm in emergency settings will require a focus on poisoning, the 10-29 age group, and the elderly. This paper will be valuable for future policies aiming to reduce the societal burden of suicide and self-harm.

• The Journal of Korean Academy of Sensory Integration
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• v.21 no.3
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• pp.65-78
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• 2023

Objective : In this study, we aimed to investigate the effectiveness of family-centered intervention conducted with caregivers of children with autism spectrum disorder (ASD) in South Korea through a systematic literature review. Methods : Previous studies published from 2011 to 2021 were searched through RISS, KISS, and DBpia. The search terms applied included "autism spectrum" OR "general developmental disorder" OR "high-functioning autism" OR "Asperger's" AND "parent education" OR "family-centered intervention" OR "parent coaching" OR "parent training" OR "family participation." A total of 11 experimental studies were chosen based on the selection criteria. Results : According to the findings on the general characteristics of the study participants, intervention strategies, and effects of the intervention, it was observed that the majority of children with ASD who participated in the study were preschool-aged, and the majority of participating caregivers were mothers. The effects of family-centered interventions were evident in both children and parents. In children, the most significant effects were observed in interaction and communication skills. In parents, a reduction in parenting stress and an improvement in parenting efficacy were observed. The intervention strategies employed in the study varied, with sensory integration intervention, responsive communication, and interaction-centered intervention being the most commonly used, followed by developmental-centered intervention, positive behavior support (PBS), and parent-mediated intervention based on pivotal response treatment (PRT). Conclusion : The results of this study are significant in that they confirm that family-centered intervention is effective not only in improving the functioning of children with autism spectrum disorder, but also in reducing parenting stress and enhancing parenting efficacy, and provide evidence for clinical use.

• Journal of Dental Anesthesia and Pain Medicine
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• v.24 no.2
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• pp.109-117
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• 2024

Background: Dental fear and anxiety are significant challenges in managing behavior in children. Oral administration of sucrose or sweet-tasting solutions has shown effectiveness in reducing procedural pain in infants and neonates. This study aimed to investigate whether pre-application of sucrose solution had an effect on minimizing pain perception during injection and to assess the potential impact of the child's age and sweet preference. Methods: A randomized control clinical trial was conducted on 60 children aged 3-9 years requiring buccal infiltration injections. Following parental consent, demographic data of the children were recorded. Sweet preferences was assessed using a modified forced-choice test. Children were equally and randomly allocated into study (sucrose) and control groups using a lottery method. Sucrose solution or distilled water, respectively, was applied to the lateral surface of the tongue for 2 min. Topical anesthetic was applied at the site of injection, followed by local anesthesia administration. The children rinsed their mouths thrice with water immediately after anesthetic injection. A video was recorded during injection which was then scored by three blinded examiners on the Sound Eye Motor (SEM) scale. The children also self-evaluated using Wong-Baker Faces Pain Rating Scale (WBFPS). Results: The mean SEM scores and WBFPS scores were analyzed using the Kruskall-Wallis test. The mean SEM score in the study group was 1.37 ± 0.61, compared to 3.17 ± 0.87 in the control group, showing a statistically significant difference (P < 0.001). Mean pain scores assessed by WBFPS in the study group were 0.60 ± 1.4, while in the control group, they were 6.27 ± 2.33, also showing a statistically significant difference (P < 0.001). Children with a sweet preference demonstrated a subjective reduction in pain perception. Conclusion: Application of sucrose before dental injections in children helps to minimize pain upon injection across all age groups.

• Journal of Korea Foundry Society
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• v.44 no.1
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• pp.3-8
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• 2024

Reducing industrial waste and improving the atmospheric environment recently have emerged as important tasks for the casting industry. Various types of artificial sand that can replace natural sand have been developed and used to solve problems that arise with the use of conventional foundry sand and to improve the foundry environment. However, only limited physical properties provided by overseas suppliers are known and in-depth comparative analyses with existing natural sand are lacking. For the design of the casting process, a wide range of thermal properties must be secured not only at room temperature but also at high temperatures. In addition, it is important to compare and analyze the differences in thermal properties between existing natural and artificial sand because changes in thermal properties require changes in the design of the casting method. In this study, the thermal behavior of the mold was analyzed through a thermal expansion test of mold blocks for natural and artificial sand., To this end, a thermal property test to evaluate thermal conductivity was performed by determining a temperature range. The results of the experiment, revealed that the thermal conductivity was 5-40% higher in artificial sand than in natural sand, and the coefficient of thermal expansion was about 15% lower for artificial sand. However, there was not a significant difference in specific heat regardless of the composition.

• Korean Journal of Psychosomatic Medicine
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• v.22 no.1
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• pp.13-22
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• 2014

Objectives : Breast cancer has been the most prevalent female cancer in South Korea since 2001. Early detection of this disease is the most effective strategy for reducing mortality. The objective of this study was to identify factors which could predict advanced stage at diagnosis of breast cancer. Methods : Participants who were initially diagnosed with breast cancer and referred to the Stress Clinic of the Breast Cancer Center at Kyungpook National University Hospital were included. Through a semi-structured interview, the authors investigated psychosocial variables such as the extent of marital and family functioning and emotional-economic family burden as well as sociodemographic and health behavior-, health characteristic- and cancer-related variables. Results : Data were collected from 219 participants. One hundred and twenty(54.8%) subjects were diagnosed with advanced-stage breast cancer. Variables that were significantly different between the advanced-stage and early-stage groups included : monthly breast self examination(p<0.000), annual mammographic screening(p<0.000), mode of tumor detection(p<0.000), nature of the first symptoms(p<0.000), time to treatment after diagnosis(p<0.000), overloaded economic and family burden(p=0.018), marital functioning(p<0.000) and family functioning(p<0.00). Logistic regression analysis indicated that irregular annual mammography screening(OR=7.431 ; 95% CI 2.407-22.944) or a lack of screening(OR=25.299 ; 95% CI 7.855-81.482) and a dysfunctional marital relationship(OR=4.772 ; 95% CI 2.244-10.145) were significantly associated with advanced stage at diagnosis of breast cancer. Conclusions : We reconfirmed screening behavior to be a risk factor for delayed diagnosis of breast cancer. Our findings also emphasized the importance of psychosocial factors such as marital functioning in early detection of breast cancer. Psychiatric consultation in the area of martial functioning could be beneficial for increasing early detection in breast cancer.