• International Journal of Highway Engineering
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• v.11 no.2
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• pp.37-44
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• 2009

Currently the reasonability of threshold values for rutting and cracking does not clearly defined at the Pavement Rehabilitation Decision Tree on national highway PMS(Pavement Management System). The goal of this study is to provide the reasonable threshold values for the national highway asphalt concrete pavement rehabilitation. To achieve this goal, test section that represents typical asphalt concrete pavement of national highway was selected and pavement export were participated. Pavement condition survey has been conducted and pavement performance data at the selected roadway section were analyzed. From this study, reasonable threshold values of Pavement Rehabilitation Decision Tree were suggested based on the pavement expert's engineering judgement. In terms of crack repairs, the application of overlay after cutting is required to deteriorated area where existing crack ratio is over 35% and just overlay is required to where crack ratio is over 20%. On rutting, rut depth over 13mm is required to overlay after cutting and rut depth over 10mm is just needed to overlay.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.479-490
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• 2012

Flexural tests on full-scale H-shaped beams, built up from high-strength steels (HSB800 and HSA800) with a nominal tensile strength of 800 MPa, was carried out to study the effect of flange slenderness of high-strength steel on flexural strength and rotation capacity. The primary objective was to investigate the appropriateness of extrapolating current stability criteria (originally developed for ordinary steel) to high-strength steel. The performance of high-strength steel specimens was very satisfactory from the strength, but not from the rotation capacity, perspective. The inferior rotation capacity of high-strength steel beams was shown to be directly attributable to the absence of a distinct yield plateau and the high yield ratio of the material. Residual stress measurements reconfirmed that the magnitude of the residual stress is almost independent of the yield stress of the base metal.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.9-17
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• 2019

PURPOSE: This research was designed to study the correlations between physical activities such as foot sensory impairment, balance and ambulatory abilities, as well as fall risk factors and mental activities such as cognitive performance and depression in order to provide fundamental data for the prevention of falling in the elderly. METHODS: A total of 36 elderly people over the age of 65 years who voluntarily joined the research were selected as subjects. Sensory perception in both feet was measured by using a monofilament in 10 parts with each part given one point. The points for each foot were integrated to analyze the correlations between physical and mental activities indices, and the results were analyzed by using Pearson's correlation coefficient. RESULTS: The results of this research show that the extent to which senses in feet were impaired was correlated to TUG, a functional activity index involved in tranfers, gait, and turning movements, which was correlated to BBS (balance index) as well as MMSE-K and K-GDS (mental activities index). BBS was interrelated to FES-K (physical activities index) and MMSE-K. The muscular strength of the right ankle dorsiflexor had mutual relations with FES-K. CONCLUSION: The results of this research indicate that TUG is widely correlated to foot sensory impairment as well as general physical and mental activities in elderly people. BBS was also shown to be correlated with TUG, FES-K, and MMSE-K. Thus, it might be necessary that TUG and BBS be included as two items in physical and mental check-ups for the elderly, and further studies on correlations using evaluation items for physical and mental activities should lead to the simplification of the evaluation criteria.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.11
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• pp.82-88
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• 2013

It is important to give lightning warning prior to a cloud-to-ground (CG) discharge within an Area of Concern (AOC) because most of lightning damage and victim are usually occurred by the first lightning in the AOC. The aim of this study is to find the optimal operation conditions of the automated lightning warning systems in order to make the best use of the available data. In this paper, the test-operated results of the automated lightning alert and risk management system (ALARM) based on detections of CG discharge and eletrostatic field and optimized at probability of lightning have been described. It was possible to obtain the following warning performance parameters: probability of detection (POD), false alarm ratio (FAR), probability of lightning (POL) and failure-to-warn rate (FTW). The data obtained from trial operation for 5months were not sufficient but the first analysis of domestic lightning warning was carried out. We have observed that the evaluated statistical results through trial operation depend on the various factors such as analysis methods and criteria, topographical conditions, etc. Also we suggest some methods for improvement of POL and POD including the finding of the optimal electric field threshold level to be used, based on the high values of FAR and FTW found in this work.

• Nuclear Engineering and Technology
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• v.2 no.3
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• pp.149-161
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• 1970

This paper describes a detailed investigational performance on the gamma radiation shield effect of heavy concretes that were manufactured by the use of mineral ores produced domestically and which may be possibly applied for the biological shield design. Ten different kinds of mineral ores were collected for use as the aggregates, physical test and chemical analysis for them were carried out to select the aggregate with a better property. Through the experimental investigation on the shielding effect of various concretes with different combination of concrete components such as water-cement and fine-coarse aggregate ratios, it was possible to derive some criteria for the best condition being capable of obtaining the concretes with high density and good uniformity. Data on the shielding-effectiveness of the different concretes were obtained by performing collimated beam experiment using 60Co gamma-ray. Analyzing the shielding-efficiency, shielding-concrete specific gravity and biological shield cost, the optimum condition of yielding the best economic shielding design, with low cost and good spatial distribution to some extent was determined.

• Journal of Radiation Protection and Research
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• v.21 no.4
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• pp.255-262
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• 1996

This paper describes the results of intercomparison measurements of KAERI reference photon and beta radiation fields between the KAERI and the PNNL(Pacific Northwest National Laboratory), recently performed at KAERI radiation calibration and dosimetry laboratory on the basis of the ANSI N13.11 criteria for personal dosimeter performance test. Each laboratory used her own radiation detectors or measurement devices traceable to her national primary standard in measuring the exposure rates for photon fields, the absorbed dose rates for beta radiation fields. The agreements in reference radiation measurements between two laboratories were found to be less than ${\pm}2.0%$ for photon fields, ${\pm}1.0%$ for beta radiation fields. Therefore, it could be concluded that KAERI reference radiation fields comply well with the international standard and thus can further serve as a national basis for the researches and developments in radiation protection dosimetry in Korea.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.4
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• pp.405-413
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• 2012

Low misclassification performance is significant with high classification accuracy for a reliable diagnosis of ECG signals, and diagnosing abnormal state as normal state can especially raises a deadly problem to a person in ECG test. In this paper, we propose detection and classification method of abnormal rhythm by rule-based rhythm classification reflecting clinical criteria for disease. Rule-based classification classifies rhythm types using rule-base for feature of rhythm section, and rule-base deduces decision results corresponding to professional materials of clinical and internal fields. Experimental results for the MIT-BIH arrhythmia database show that the applicability of proposed method is confirmed to classify rhythm types for normal sinus, paced, and various abnormal rhythms, especially without misclassification in detection aspect of abnormal rhythm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.576-582
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• 2016

To cope with international regulations, such as Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and so forth, and to enforce limitations on $CO_2$ emissions, green-ship technology to lower fuel consumption has been actively researched, and the development of an energy-saving device (ESD) is being pursued. In order to design an ESD for small and medium-sized domestic vessels, an analysis on flow characteristics has been performed in the present study. Through a model test and numerical analyses, the characteristics of flow around the stern bilge and bulb have been compared to improve wake quality and resistance performance. As a result of these comparisons and analyses, a vertical plate has been adopted,, as a new ESD. Design criteria for the proposed ESD are also suggested. By applying this new ESD, it is expected that the total resistance and average nominal wake can be reduced by 3.04 % and 18.8 %, respectively.

• Steel and Composite Structures
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• v.28 no.3
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• pp.363-380
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• 2018

This paper presented an integral design procedure for demountable bolted composite frames with semi-rigid joints. Moment-rotation relationships of beam-to-column joints were predicted with analytical models aiming to provide accurate and reliable analytical solutions. Among this, initial stiffness of beam-to-column joints was derived on the basis of Timoshenko's plate theory, and moment capacity was derived in accordance with Eurocodes. The predictions were validated with relevant test results prior to further applications. Frame analysis was conducted by using Abaqus software with material and geometrical nonlinearity considered. Variable lateral loads incorporating wind actions and earthquake actions in accordance with Australian Standards were adopted to evaluate the flexural behaviour of the composite frames. Strength and serviceability limit state criteria were utilized to verify configurations of designed models. A wide range of frames with the varied number of storeys and bays were thereafter programmed to ascertain bending moment envelopes under various load combinations. The analytical results suggest that the proposed approach is capable of predicting the moment-rotation performance of the semi-rigid joints reasonably well. Outcomes of the frame analysis indicate that the load combination with dead loads and live loads only leads to maximum sagging and hogging moment magnitudes in beams. As for lateral loads, wind actions are more crucial to dominate the design of the demountable composite frames than earthquake actions. No hogging moment reversal is expected in the composite beams given that the frames are designed properly. The proposed analysis procedure is demonstrated to be a simple and efficient method, which can be applied into engineering practice.

• Journal of the Korean Society for information Management
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• v.32 no.2
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• pp.193-219
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• 2015

The focus of traditional evaluations of ontologies is largely performance-based. A comparison of a new ontology with well-established ones, testing of ontologies in different applications, as well as any judgment of an ontology's appropriateness and relatedness to source data heavily rely on what results that ontology seems to manifest. This study, on the other hand, is an attempt to evaluate the quality of a particular ontology as manifested by its structure, representation, and interoperability. To that end, major categories of quality evaluations were first identified through an extensive survey of literature. Evaluation questions were formulated from these categories using the Delphi method and were validated by ontology experts. The entire process produced a set of 53 evaluation questions, which was then employed to test the quality of a newly-developed smartphone ontology.