• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.130-137
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• 2023

This study analyzed the effect of mixing order on the flowability, compressive strength, and flexural strength of cement composites reinforced with polyvinyl alcohol(PVA) fibers and multi-walled carbon nanotubes(MWCNTs). The experimental results showed that the addition of CNTs significantly reduced the flowability, and the flowability was considerably affected by the mixing order when CNTs were added. The compressive strength was most effectively improved when water and CNTs solution were mixed first before adding PVA fibers, and the flexural strength was highest when water and CNTs solution were mixed with PVA fibers after dry mixing. However, there was no clear correlation between the flexural toughness and the mixing order. In addition, scanning electron microscopy(SEM) image analysis was conducted to analyze the microstructure. The SEM images showed that CNTs were randomly dispersed through the specimens and contributed to the strength improvement, but the effect of the mixing order was not clearly observed. The main results of this study are expected to be useful for evaluations of workability and material performance of PVA fiber-reinforced cement composites with CNTs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5C
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• pp.293-301
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• 2008

Soil profiling is one of the most important work among geotehnical engineering practice. Generally, soil profile is estimated from the observation of soil samples during subsurface exploration but such estimation also includes some experiencing aspects such as flushed water from the borehole, slime colour, boring speed and so on. In addition, since the capacity of hydraulic drill rig is significantly increased, thin layers might be easily missed. So, continuous soil profile is almost impossible over all depth to be bored from conventional subsurface exploration. While CPT or CPTu can serve continuous soil profile information over all depth generally in 5cm interval. Many charts or methods for soil profile from CPT result have been proposed during last several decades over the world. However they have not been verified in local ground condition in Korea. In this research, CPT results and soil classification results based on USCS were compiled from 17 sites over the Korea. Soil classification results by using 7 CPT soil classification charts were compared with those of USCS for the compiled database. Most proper CPT soil classification chart for Korean soil characteristics was evaluated and effective parameters for the soil classification from CPT were discussed. Finally interrelationship between CPT soil classification chart and USCS soil classification was evaluated.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.79-89
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• 2023

The inventory of many materials requires a large storage space, and the longer the storage period, the higher the potential maintenance cost. When materials are stored on a construction site, there are also concerns about safety due to the reduction of room for movement and working. On the other hand, construction sites that do not store materials have insufficient inventory, making it difficult to respond to demands such as sudden design changes. Ordering materials is then subject to delays and extra costs. Although securing an appropriate amount of inventory is important, in many cases, material management on a construction site depends on the experience of the site manager, so a reasonable material inventory management plan that reflects the construction conditions of a site is required. This study proposes an economical material management method by reflecting variables such as the status of the preceding and following activities, site size, material delivery cost, timing of an order, and quantity of orders. To this end, we set the appropriate inventory amount while adjusting related activities in the activity network, using float time for each activity, the size of the yard, and the order quantity as the main variables, and applied a genetic algorithm to this process to suggest the optimal order timing and order quantity. The material delivery cost derived from the results is set as a fitness index and the efficiency of inventory management was verified through a case application.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.583-593
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• 2019

The purpose of this study was to investigate the relation between and subjective instability pain behavior (SIPB) and physical instability test(PIT) according to the presence of characteristic past histories(CPH) in people with chronic low back pain(CLBP). Forty CLBP subjects participated in this study. The presence of four characteristics past histories(long term history, traumatic experience, sports activities, neurologic sign) were examined. According to presence number(PN) of CPH, subjects were divided into 5 groups[group 1(PN:0): n=8, group 2(PN:1): n=8, group 3(PN:2): n=8, group 4(PN:3): n=8, group 5(PN:4): n=8]. After 16 items were examined for the SIPBs, then Seven PITs were conducted, and the results were scored. The SIPBs and PITs were compared according to the presence numbers of CPH, and the relation between them was analyzed. There was a significant difference(p<.05) in both SIPB scores and PIT scores in the comparison of groups according to the presence number of CPH. There was high positive correlation between the presence numbers of CPH and SIPB score(r=.819, p=.000) and PIT score(r=.606, p=.000). Also, there was a correlation between SIPB score and PIT score(r=.571, p=.000). Based on the findings in the present study, the presence of three or more CPH in people with CLBP may be a useful variable in the diagnosis of lumbar instability. The combined findings of the three variables such as CPH, SIPB, and PIT can improve the accuracy of lumbar instability diagnosis.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.433-439
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• 2023

In this study, the bonding performance of repair materials was evaluated on concrete repair surface to develop concrete repair materials based on UHPC (Ultra High Performance Concrete) which has high mechanical and durability performance. The ten test variables were applied considering the roughness and wet condition of the concrete surface subject to repair, the addition of polymer, and the use PP and PVA fibers in repair materials. The addition of the polymer caused a significant decrease in strength, which was thought to be due to the effect of the additional super plasticizer used to adjust workability. Also, flow was reduced by up to 13.8 % with the use of plastic-based fibers. As a result of evaluating the bond strength of the repair material considering the condition of the surface subject to repair, it was thought that in the case of using UHPC-based repair material, high bonding performance could be secured without any additional surface treatment as long as the surface of the base material was sound. In addition, UHPC-based repair materials showed high bonding performance even when the attachment surface was wet. In the future, research will be conducted on shot-crete application and gradient pouring for the development of UHPC-based repair materials, and continuous improvement in the repair material mixing property will be carried out to ensure economic efficiency and performance as a concrete structural repair material.

• The Journal of Korean Academy of Sensory Integration
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• v.21 no.2
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• pp.58-68
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• 2023

Objective : This study aimed to analyze papers published in the Journal of Korean Academy of Sensory Integration over the past 10 years. Methods : This study analyzed 130 papers published in the Journal of Korean Academy of Sensory Integration from June 2013 to December 2022. The data analysis was performed by dividing the papers based on the researchers' region and affiliation, research type(s), level of evidence, participants, and field of research. Results : The researchers were mostly from the Gyeongsang-do region and universities. With regard to the type of research, descriptive research was the most common. Most studies were categorized as research level IV studies. Moreover, the number of level IV studies steadily increased on a year-by-year basis. Regarding the study participants, the studies most commonly concerned the diagnosis of attention deficit hyperactivity disorder. In terms of the field of study, the application of individual sensory integration therapy was most common, while the application of modified applications such as Ayres Sensory Integration^® and remote sensory integration therapy programs was also noted. Conclusion : This study examined the recent research trends in the Journal of Korean Academy of Sensory Integration by analyzing the research type(s), level of evidence, participants, and field of research. The present results will help readers understand the research trends in the field of sensory integration therapy and pediatric intervention, and they will also contribute to the amount of evidence available.

• Journal of Industrial Convergence
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• v.21 no.12
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• pp.101-111
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• 2023

This study conducted systematic review and meta-analysis to analyze the effectiveness of a dual-task for cognitive function in patients with MCI in Korea. A search was conducted using eight databases, and the search terms were MCI, cognition, and dual task. This study includes RCT and nonRCT published from January 2013 to July 2023. A total of 682 studies were searched, and 8 studies that fulfilled the inclusion and exclusion criteria were finally analyzed. Methodological quality was assessed with the RoB, RoBANS. The meta-analysis used CMA 4.0 ver. As a result of the analysis, the overall effect size of the dual task was medium effect size. The effect size according to the outcome variables was large for orientation and executive function, and medium effect size for global cognitive function, visuospatial function, memory, and attention. As a result of analysis according to the intervention period, the effect was greater when applied for 4 to 8 weeks, and the effect size was larger when applied for 24 to 30 sessions. This study presented clinical evidence on the effectiveness and application method of a dual-task applied to improve cognitive function in patients with MCI.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.97-107
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• 2024

Despite the rapid advancement in image recognition technology, achieving perfect digitization of tabular documents and handwritten documents still challenges. The purpose of this study is to improve the accuracy of digitizing the logbook by correcting errors by utilizing associated rules considered during logbook entries. Through this, it is expected to enhance the accuracy and reliability of data extracted from logbook through OCR programs. This model is to improve the accuracy of digitizing the logbook of the training ship "Saenuri" at the Mokpo Maritime University by correcting errors identified after Optical Character Recognition (OCR) program recognition. The model identified and corrected errors by utilizing associated rules considered during logbook entries. To evaluate the effect of model, the data before and after correction were divided by features, and comparisons were made between the same sailing number and the same feature. Using this model, approximately 10.6% of errors out of the total estimated error rate of about 11.8% were identified, and 56 out of 123 errors were corrected. A limitation of this study is that it only focuses on information from Dist.Run to Stand Course sections of the logbook, which contain navigational information. Future research will aim to correct more information from the logbook, including weather information, to overcome this limitation.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.7 no.1
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• pp.92-109
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• 1996

The objectives of the present study were to provide comprehensive assessment of the impact of epilepsy on the psychological well-being of children with epilepsy and to identify the neurological factors associated with the psychopathology. The participant patients were recruited from the population of children and adolescent aged 7 to 16 attending the OPD of department of pediatric neurology in Seoul National University Hospital in Korea. We exclude mental retardation, pervasive developmental disorder and brain organic pathology. As control group, formal students were chosen and their sex, age, achievement, socioeconomic status were matched to patients. The first author interviewed the children and their family members and obtained the developmental history and family information. We used the following 10 scales for assessing psychological and behavioral problems in patients and their family member. The scales were standardized and their validity and reliability were confirmed before. Parent rating scales : Yale children's inventory, Disruptive behavior disorder scale, Parent's attitude to epilepsy questionnaire, Family environment scale, Symptom check-list-90 revision, Children behavior check-list. Children's self rating scales : Children's depression inventory, Spielberger's state-trait anxiety anxiety, Piers-Harris self-concept inventory and Self-administered Dependency questionnaire for Mother. The result showed the risk factors associated depression were early onset, complex partial seizure, lateralized temporal focal abnormality on EEG, Drug polypharmacy, high seizure frequency and sick factors associated anxiety were old age of patient, lateralized temporal focal abnormality EEG, Drug polypharmacy, high seizure frequency. Also the result of this present study indicated that risk factors associated oppositional defiant disorder, conduct disorder and attention deficit hyperactivity disorder were young age, male, early onset, lateral temporal EEG abnormality and high seizure frequency. According to these results, common risk factors associated psychological and behavioral problems were lateralized EEG temporal abnormality, high seizure frequency in neurological factors.

• The Journal of Korean society of community based occupational therapy
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• v.7 no.2
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• pp.1-8
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• 2017

Objectives : This study was conducted to investigate the activity of the supra and infrahyoid muscles according to the temperature and the amount of water in healthy adults. Methods : The amount of water was set to 3 mL and 20 mL, and the temperature was subdivided into $4^{\circ}C$, $22^{\circ}C$, and $40^{\circ}C$ in order to compare the activity of the supra and infrahyoid muscles in twenty-seven healthy adults. We used the mean value of the activity of the supra and infrahyoid muscles while they were swallowing saliva in order to set the reference voluntary contraction (%RVC). Results : Muscle activity was significantly increased when they swallowed 20 mL of water rather than 3 mL in the left infrahyoid muscles at $4^{\circ}C$, $22^{\circ}C$ and $40^{\circ}C$ (p=.00; p=.00; p=.00), the right infrahyoid muscles at $22^{\circ}C$and $40^{\circ}C$ (p=.01; p=.01), the left suprahyoid muscles at $4^{\circ}C$ (p=.03). Muscle activity of the right suprahyoid muscles was significantly decreased at $40^{\circ}C$ compared to $4^{\circ}C$ and $22^{\circ}C$ when they swallowed 20 mL of water (p=.04). Conclusion : In the future, other variables such as viscosity and taste should be considered, and further studies on patients with impaired nervous system as well as healthy subjects will be needed.