• Tribology and Lubricants
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• v.39 no.6
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• pp.250-255
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• 2023

This study applies various surface patterns to minimize material loss in construction equipment that is subject to severe wear due to sand, such as the wear-resistant steel plates of dump trucks or the teeth of excavators. The relationship between surface morphology and wear behavior is investigated using PLA+ polymer to observe the effect of the surface pattern. Five types of samples - smooth, concave, convex, wavy concave, and wavy convex designs - are created using a 3D printer. A wear experiment is conducted for a duration of 3 h using 6.5 kg of abrasive particles. The mass loss of the samples after the experiment is measured to assess the extent of wear. Additionally, the surface morphology of the samples before and after the experiment is analyzed using SEM and confocal microscopy. The study results reveal that the smooth design exhibits the highest wear loss, whereas the concave and wavy concave designs show relatively lower wear loss. The convex and wavy convex designs exhibit varying contact areas with the abrasive particles depending on the surface pattern, resulting in different levels of wear. Furthermore, a comparison between the experimental results and DEM simulations confirms the observed wear trends. This study reveals the relationship between wear damage according to surface pattern shape and is expected to be of substantial help in the analysis of wear and tear on agricultural and heavy equipment.

• The Research Journal of the Costume Culture
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• v.32 no.2
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• pp.199-214
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• 2024

Until now, research on consumers' purchasing behavior has primarily focused on psychological aspects or depended on consumer surveys. However, there may be a gap between consumers' self-reported perceptions and their observable actions. In response, this study aimed to investigate consumer purchasing behavior utilizing a big data approach. To this end, this study investigated the purchasing patterns of fashion items, both online and in retail stores, from a data-driven perspective. We also investigated whether individual consumers switched between online websites and retail establishments for making purchases. Data on 516,474 purchases were obtained from fashion companies. We used association rule analysis and K-means clustering to identify purchase patterns that were influenced by customer loyalty. Furthermore, sequential pattern analysis was applied to investigate the usage patterns of online and offline channels by consumers. The results showed that high-loyalty consumers mainly purchased infrequently bought items in the brand line, as well as high-priced items, and that these purchase patterns were similar both online and in stores. In contrast, the low-loyalty group showed different purchasing behaviors for online versus in-store purchases. In physical environments, the low-loyalty consumers tended to purchase less popular or more expensive items from the brand line, whereas in online environments, their purchases centered around items with relatively high sales volumes. Finally, we found that both high and low loyalty groups exclusively used a single preferred channel, either online or in-store. The findings help companies better understand consumer purchase patterns and build future marketing strategies around items with high brand centrality.

• 대한상한금궤의학회지
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• v.15 no.1
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• pp.85-115
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• 2023

Objectives : This study reports on the cases of four ADHD patients who treated with herbal medication based on Disease Pattern Identification Diagnostic System (DPIDS). Methods : Two children and two adults were diagnosed with ADHD according to DSM-V, and Galgeunhwangryeonhwanggeum-tang was administered. The parents of the two children completed the Korean ADHD Rating Scale (K-ARS) before and after treatment, while the other patients used the Korean ADHD Self Rating Scale (K-ASRS). The patients' somatic symptoms and other issues were evaluated through interviews. Results : In the first case, the K-ARS scale exhibited a change from 28 to 3. The patient demonstrated improvements in attention, concentration, and social behavior, along with the elimination of self-injurious behavior. In the second case, the K-ARS scale showed a change from 41 to 9. The patient in the third case demonstrated improved chronic fatigue, increased attention, work efficiency, and enhanced social skills, leading to maintaining employment for over six months for the first time in their life after the treatments. Additionally, the patient in the fourth case demonstrated improved work concentration and relief in nocturia. Conclusions : In this study, four patients exhibited improvements in symptoms of attention deficit, hyperactivity, and impulsivity before and after herbal treatment, leading to enhanced academic and social relationships. As the patients progressed in their health restoration, symptoms related to the genitourinary system also showed improvement.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.13 no.1
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• pp.177-188
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• 2002

Objectives：The major goal of this study was to investigate and compare the behavior problems and mothers' rearing pattern between adolescent psychiatric patients either neglected or rejected by peer and those who were neither neglected nor rejected by peer. Methods：Adolescent psychiatric patients(N=25) performed peer neglect scale, peer reject scale. And their mothers performed the part of Child Behavior Checklist(CBCL), Maternal Behavior Research Instrument(MBRI), the scale for the maternal concern about the social life of their own patients, and the scale for maternal concern about the friendship of their own patients. According to the score of the peer neglect scale and the peer reject scale, we divided the patients into 'peer neglect-reject' group(n=15) and ‘on-loneliness’ group(n=10), and compared the scores of other scales between each group. Also, we investigated the correlation among all scales. Results：1) The scores of the part of CBCL(p<.05), depressed/anxious subscale of CBCL(p<.05) and thought problem subscale of CBCL(p<.01) in peer neglect-reject group were significantly higher than those in non-neglect group. The score of peer neglect scale was significantly correlated with that of the part of CBCL(r=.516), depressed/anxious subscale of CBCL(r=.483), thought problem subscale of CBCL (r=.651), social problem subscale of CBCL(r=.517). And the score of peer reject scale was significantly correlated with that of attention subscale of CBCL(r=.414), thought problem subscale of CBCL(r=.446), social problem subscale of CBCL(r=.531). 2) But, each group was not significantly different on the scores of MBRI, the scale for the maternal concern about the social life of their own patients, and the scale for maternal concern about the friendship of their own patients. And there were no significant correlation between the scores of peer neglect / peer reject scale and those of scales for maternal rearing pattern. Conclusion：The thought problem and depression/anxiety problem of adolescent psychiatric patients neglected or rejected by peer were estimated more higher than those of adolescent psychiatric patients neither neglected nor rejected by peer. But, from the view of maternal rearing pattern, each 2 groups seemed not to be different. Further research using more subjects will be needed.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.75-84
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• 2008

In 2002, the 5-day workweek policy was effective in Korea. As we have expected, the 5-day workweek policy has changed people's travel behavior during weekdays and weekends. Several studies have been done to understand these changes and impacts on transportation systems. However, these studies have only focused on travel pattern changes without considering spatial factors. Said in another way, although individual travel pattern changes are usually investigated, indices adopted cannot describe travel pattern changes in a proper way due to lack of the spatial distribution measure. This study aims to analyze travel change since the 5-day work week policy in effect using a new index (i.e. Travel Vector Index) developed in this study, which can explain travel pattern changes in terms of magnitude and spatial point of views. The new index uses a GIS technology and TCS (Toll Collection System) databases in Korea. The results in this study show that the index is very useful and reliable to measure the travel patterns changes. They are applied to TCS data set and the results show that the 5-day workweek policy significantly affects on travel behaviors.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1184-1191
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• 2016

This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips. In order to make the proposed methodology practical forward, all the transient scenarios registered in a simulator of a 1,000 MWe pressurized water reactor were archived in the transient pattern database. The transient patterns show plant behavior until turbine-generator trip when there is no operator's intervention. Meanwhile, the operating data periodically captured from a plant computer is compared with an individual transient pattern in the database and a highly matched section among the transient patterns enables isolation of the type of transient and prediction of the expected remaining time to trip. The transient pattern database consists of hundreds of variables, so it is difficult to speedily compare patterns and to draw a conclusion in a timely manner. The transient pattern database and the operating data are, therefore, converted into a smaller dimension using the principal component analysis (PCA). This paper describes the process of constructing the transient pattern database, dealing with principal components, and optimizing similarity measures.

• Advances in pediatric surgery
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• v.1 no.1
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• pp.1-7
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• 1995

The acetylcholinesterase(ACHE) activity in 37 biopsies from the patients with Hirschsprung's disease was analyzed for histochemical patterns according to age, and its evolutional behavior was also assessed. The histochemical criterion used for the diagnosis of Hirschsprung's disease was that of Chow, i.e., "the presence of many coarse discrete cholinergic fibers in the muscularis mucosae and in the immediately subjacent submucosa regard less of an infiltration of cholinergic fibers in the lamina propria." The acetylcholinesterase activity in Hirschsprung's disease was further classified into 3 patterns, advocated by de Brito and Maksoud : Pattern I-many thick fibers exclusively in the muscularis mucosae and submucosa(newborn pattern). Pattern II-many thin fibers in the muscularis mucosae and submucosa with a clear infiltration of cholinergic fibers in the lamina propria(classical pattern). Pattern III-an intermediate pattern showing morphological characteristics of the two patterns with predominance of one or the other. Of 37 biopsies, Pattern 1 was seen exclusively in 16 biopsies taken from the neonates. Pattern III was 11 of 37 biopsies and it was mainly seen in children between 2 to 12 months of age. Pattern II was seen in all 3 biopsies of older than 1 year of age and in 6 ones of 3 to 12 months of age. In summary, this study reinforces the impression that there is an evolutional character of the distribution and morphology of the cholinergic ACHE positive fiber with age. In other words, ACHE activity in Hirschsprung's disease appears to evolve with age from the newborn pattern to the intermediate pattern finally to the classical pattern.

• Smart Structures and Systems
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• v.21 no.4
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• pp.421-433
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• 2018

Carbon fiber reinforced polymer (CFRP) cable has good mechanical properties and corrosion resistance. However, the anchorage of CFRP cable is a big issue due to the anisotropic property of CFRP material. In this article, a high-efficient bonding anchorage with novel configuration is developed for CFRP cables. The acoustic emission (AE) technique is employed to evaluate the performance of anchorage in the fatigue test and post-fatigue ultimate bearing capacity test. The obtained AE signals are analyzed by using a combination of unsupervised K-means clustering and supervised K-nearest neighbor classification (K-NN) for quantifying the performance of the anchorage and damage evolutions. An AE feature vector (including both frequency and energy characteristics of AE signal) for clustering analysis is proposed and the under-sampling approaches are employed to regress the influence of the imbalanced classes distribution in AE dataset for improving clustering quality. The results indicate that four classes exist in AE dataset, which correspond to the shear deformation of potting compound, matrix cracking, fiber-matrix debonding and fiber fracture in CFRP bars. The AE intensity released by the deformation of potting compound is very slight during the whole loading process and no obvious premature damage observed in CFRP bars aroused by anchorage effect at relative low stress level, indicating the anchorage configuration in this study is reliable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.2
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• pp.108-113
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• 2003

Research results have demonstrated that conventional client-server databases have scalability problem in the presence of many concurrent clients. The multi-tier architecture that exploits similarities in clients' object access behavior partitions clients into logical clusters according to their object request pattern. As a result, object requests that are served inside the clusters, server load and request response time can be optimized. Management of clustering by utilizing clients' access pattern-based is an important component for the system's goal. Off-line methods optimizes the quality of the global clustering, the necessary cost and clustering schedule needs to be considered and planned carefully in respect of stable system's performance. In this paper, we propose methods that detect changes in access behavior and optimize system configuration in real time. Finally this paper demonstrates the effectiveness of on-line change detection and results of experimental investigation concerning reconfiguration.

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.155-167
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• 2004

In this paper, the inelastic buckling behavior of the beam under uniform bending was investigated using the energy-based method, which can tackle problems in fourth order eigenvalue. The pattern of residual stress was not available to satisfy the I-sections manufactured in Korea. however; therefore, the well-known polynomial and simplified pattern of residual stress was adopted in this study. The inelastic lateral-distortional buckling behavior of the beam with I-sections manufactured in Korea was investigated. The study was then extended to the inelastic lateral-torsional buckling of the beam by minimizing the out-of-plane web distortion. The inelastic lateral-torsional buckling results obtained in this paper were compared with the prediction of allowable bending stress given in the Korean steel designers' manual (1995). Results showed that the importance of inelastic lateral-distortional buckling did not arise for beams under uniform bending. Likewise, the design method in KSDM (1995) was proven to bo too conservative for intermediate and short spans of beams without intermediate bracing.