• Korean Journal of Heritage: History & Science
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• v.56 no.1
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• pp.6-19
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• 2023

As data management and intelligence capability become proxy indicators of national power, the risk provoked by high depending on digital technology ironically increases. The quicker the changes come to be, the more important digitizing existing data and management of digital data are. The management of archaeological data could not be exceptional. It has to be performed in a more comprehensive, systematic and rapid manner. In order to perform the task, the nature of archaeological data contained in the digital archive should be properly recognized in advance: the primary data are generated by excavation as a process destroying their sources, the data are enormous in type and quantity, including long-term and various human experience, and the natural extinction of primary data in handwritten form is likely to be more crucial than in any other discipline. These characteristics of archaeological data unimaginably devastated the possibility of recovering archives, when we face a digital dark age. Considering both recent trend and the nature of archaeological data mentioned above, we can derive strategies for building a sustainable archaeological digital archive. As an archaeology-major consumer of the digital data, I propose four strategic considerations: ① establishing a system of digital data literacy; ② enhancing evaluation and capability of data reuse; ③ building an international data sharing system; ④ developing it into the platform for digital archaeology.

• The Journal of Bigdata
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• v.7 no.1
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• pp.15-27
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• 2022

In the past five years, the fatality rate of single-vehicle accidents has been 4.7 times higher than that of all accidents, so it is necessary to establish a system that can detect and respond to single-vehicle accidents immediately. The IoT(Internet of Thing)-based real-time traffic accident recognition system proposed in this study is as following. By attaching an IoT sensor which detects the impact and vehicle ingress to the guardrail, when an impact occurs to the guardrail, the image of the accident site is analyzed through artificial intelligence technology and transmitted to a rescue organization to perform quick rescue operations to damage minimization. An IoT sensor module that recognizes vehicles entering the monitoring area and detects the impact of a guardrail and an AI-based object detection module based on vehicle image data learning were implemented. In addition, a monitoring and operation module that imanages sensor information and image data in integrate was also implemented. For the validation of the system, it was confirmed that the target values were all met by measuring the shock detection transmission speed, the object detection accuracy of vehicles and people, and the sensor failure detection accuracy. In the future, we plan to apply it to actual roads to verify the validity using real data and to commercialize it. This system will contribute to improving road safety.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.699-707
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• 2008

For most structural evaluation of bridge integrity, it is very important to measure the geometric profile, which is a major factor representing the global behavior of civil structures, especially bridges. In the past, because of the lack of appropriate methods to measure the deflection profile of bridges on site, the measurement of deflection has been restricted to just a few discrete points along the bridge, and the measuring points have been limited to the locations installed with displacement transducers. Thus, some methods for predicting the static deflection by using fiber optic strain sensors has been applied to simply supported bridges. In this study, a method of estimating the static deflection profile by using strains measured from suspension bridges was proposed. Based on the classical deflection theory of suspension bridges, an equation of deflection profile was derived and applied to obtain the actual deflection profile on Namhae suspension bridge. Field load tests were carried out to measure strains from FBG strain sensors attached inside the stiffening girder of the bridge. The predicted deflection profiles were compared with both precise surveying data and numerical analysis results. Thus, it is found that the equation of predicting the deflection profiles proposed in this study could be applicable to suspension bridges and the FBG strain sensors could be reliable on acquiring the strain data from bridges on site.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.765-778
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• 2008

Performance Profiles are essential to predict the performance variation over time for the bridge management system (BMS) based on risk management. In general, condition profiles based on experts opinion and/or visual inspection records have been used widely because obtaining profiles based on real performance is not easy. However, those condition profiles usually don't give a good consistency to the safety of bridges, causing practical problems for the effective bridge management. The accuracy of performance evaluation is directly related to the accuracy of BMS. The reliability of the evaluation is important to produce the optimal solution for distributing maintenance budget reasonably. However, conventional methods of bridge assessment are not suitable for a more sophisticated decision making procedure. In this study, a method to compute quantitative performance profiles has been proposed to overcome the limitations of those conventional models. In Bridge Management Systems, the main role of performance profiles is to compute and predict the performance of bridges subject to lifetime activities with uncertainty. Therefore, the computation time for obtaining an optimal maintenance scenario is closely related to the efficiency of the performance profile. In this study, the Response Surface Method (RSM) based on independent and important design variables is developed for the rapid computation. Steel box bridges have been investigated because the number of independent design variables can be reduced significantly due to the high dependency between design variables.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.43-52
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• 2006

Despite several constitutive models have been proposed and applied, it is still difficult to choose a suitable model and to estimate adequate analysis parameters. Furthermore, a cyclic shear behavior under the volume change caused by the seepage is more complex. None of the constitutive model is available at present in the expression of the cyclic behavior of soil under an additional volume change condition by seepage. Therefore, a new geotechnical hybrid simulation system which can control the pore water immigration was developed. The system enables a quantitative evaluation of the residual deformation such as lateral spreading and settlement caused by the liquefaction. The seismic responses in a one-dimensional slightly inclined multilayered soil system are taken into consideration, and the soils are governed by both equation of motion and the continuity equation. Furthermore, the estimation and the selection of the soil parameter for the representation of the strong nonlinearity of the material are not required, because soil behaviors under the earthquake motions are directly introduced instead of a numerical soil constitutive model. This paper presents the concept and specifications of the system. By applying the system to an example problem, the permeability effect on the seismic response during cyclic shear is studied. The importance of the volume change characteristics of sandy soil during and after cyclic shear is shown in conclusion.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.62-69
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• 2023

Re-damage is frequently occurring for various reasons, including material factors, external factors, and factors caused by poor construction in concrete cross-section restoration work, so it is necessary to identify the cause and improve it. Cement-based materials are the most commonly used maintenance materials for concrete structures, and in particular, additional cross-sectional restoration work may be carried out due to re-damage such as cracks and excitement due to dry contraction of the repair material. In this study, a basic study was conducted to identify the characteristics of concrete while diversifying the maximum dimensions and assembly rate of thick aggregates to examine the effects of using thick aggregates in repair materials. As a result, the slump of concrete increased as the maximum size of thick aggregates increased, and the amount of air content was measured 1.88 to 2.35 times higher in the mixing using aggregates with a maximum aggregate size of 5 mm or more compared to the mixing group with a maximum aggregate size of 10 mm or more. It was found that compressive strength was greatly affected by the performance rate of thick aggregates. The compressive strength was measured the highest in the mixture using thick aggregates with the highest performance rate of 20 mm, and the compressive strength of the mixture with the lowest performance rate was more than 45%. As a result of the dry shrinkage measurement, the dry shrinkage was the lowest as the performance rate of the thick aggregate increased according to the change in the maximum dimensions and assembly rate of the thick aggregate, and the lowest performance rate was the largest in the mix. Through this study, it was confirmed that adjusting the particle size by diversifying the maximum dimensions and assembly rate of thick aggregates used in concrete structure repair materials can improve strength and workability and reduce dry shrinkage.

• Tunnel and Underground Space
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• v.33 no.6
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• pp.534-546
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• 2023

If the disc cutter is excessively worn or damaged, it becomes incapable of rotating and efficiently cutting rockmass. Therefore, it is important to appropriately manage the replacement cycle of the disc cutter based on its degree of wear. In general, the replacement cycle is determined based on the results of manual inspection. However, the manual measurements has issues related to worker safety and may lead to inaccurate measurement results. For these reasons, some foreign countries are developing the real-time measurement system of disc cutter wear by using different sensors. The ultrasonic sensors, eddy current sensors, magnetic sensors, and others are utilized for measuring the wear amount of disc cutters. In this study, the applicability of eddy current sensors for real-time measurement of wear amount in TBM disc cutters was evaluated. The distance measurement accuracy of the eddy current sensor was assessed through laboratory tests. In particular, the accuracy of eddy-current sensor was evaluated in various environmental conditions within the cutterhead chamber. In addition, the measurement accuracy of the eddy current sensor was validated using a 17-inch disc cutter.

• The Transactions of the Korea Information Processing Society
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• v.13 no.8
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• pp.374-381
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• 2024

Documentation repositories on GitHub are used to share information that is helpful in performing various tasks. Popular documentation repositories have an advantage in attracting contributors who can help manage and extend documentation repository. Therefore, it is important to understand the characteristic of documentation repositories helpful to obtain popularity for developing strategies attracting attention of users. This paper presents a study on GitHub documentation repositories. To conduct the study, we collected 566 documentation repositories from GitHub and manually categorized their topic into 30 topics. Based on the stargazer score of the collected documentation repositories, we divided the collected documentation repositories into popular and unpopular documentation repository groups and investigated the topics in the popular documentation group. Then we statistically examined the differences in README characteristics of the popular and unpopular documentation repository groups. As a result, we found that the studied documentation repositories have 23 popular topics. We also found that the popular and unpopular documentation repository groups have differences in 5 README characteristics. The result of our study indicates that what documentation repository become popular in GitHub.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.442-448
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• 2016

This study was conducted to determine the appropriateness of systemic radiation exposure control for students in clinical practice by comparing radiation exposure in radiography employees at different stations of a hospital with that of students conducting clinical practice using identical stations. Overall, 121 students who conducted clinical practice in the department of radiology area of C university hospital from July 2014 to August 2014 and 62 workers working in the same medical facility (47 in the department of radiology, 8 in the department of radiation oncology, 7 in the department of nuclear medicine) were investigated. The radiation exposure experienced by students was measured for 8 weeks, which is the duration of the clinical practice. Additionally, radiation exposure of workers were classified into 4 groups, department of radiology, department of radiation oncology, and department of nuclear medicine was compared. Dose was measured with OSLD and differences among groups were identified by ANOVA followed by Duncan's multiple range test. Among employees, those in the department of radiology, oncology and nuclear medicine were exposed depth doses of $0.127{\pm}0.331mSv$, $0.01{\pm}0.003mSv$, and $0.431{\pm}0.205mSv$, respectively, while students were exposed to $0.143{\pm}0.136mSv$. Additionally, workers in the department of radiology, oncology and nuclear medicine were exposed to surface doses of $0.131{\pm}0.331mSv$, $0.009{\pm}0.003mSv$, and $0.445{\pm}0.198mSv$, respectively, while students were exposed to $0.151{\pm}0.14mSv$, which was significantly different in both doses (p < 0.01). The average dose that students received is higher than that of the other groups (except for nuclear medicine workers), indicating that further improvements must be made in systemic controls for individual radiation exposure by including the students as subjects of management for protection from radiation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5684-5691
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• 2011

The purpose of this study is to examine effects of constraint-induced movement therapy(CIMT) and/or cognitive-perceptual training(CPT) on the change of hand function in cerebrovascular accident(CVA) patients and to evaluate the change in the amount and quality of use of the affected upper extremity in performing daily living tasks. The subjects of study were 10 patients who had been under rehabilitation for more than three months after CVA onset. They were all determined as mild cognition impairment according to NCSE or MVPT test. For CIMT group, to restrict the movement of the unaffected hand the subjects had been worn modified resting arm-splint in daytime for 4 weeks. For CIMT+CPT group, the subjects were performed CPT with CIMT and control group had been under conventional occupational therapy for the same period. CIMT+CPT group showed significant improvement in simulated feeding, lifting large light objects, and lifting large heavy objects of Jebsen-Taylor Hand Function Test. CIMT group also showed significant improvement compared with control group. The mean changes of the amount of use(AOU) of the affected arm had a statistically significant difference among groups (p<.05). While CIMT+CPT group had the biggest change in the quality of movement(QOM) of upper extremity of the affected side, CTL group showed the smallest change. Both CIMT and CIMT+CPT groups had statistically significant difference in the change in the quality of movement in upper extremity of affected side with CTL group(p<.05), but there was not significant difference between CIMT group and CIMT+CPT group. CIMT performed to the patients of stroke, with mild impairment in cognitive perceptual abilities showed the improvement in hand movement and AOU and QOM of upper extremity in the affected side and the combination of CIMT with CPT showed synergic effects.