• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.617-624
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• 2021

Concrete-filled steel tubular columns can improve the strength and deformation capacity of structures, thereby enabling the development of efficient structures. The Korean design standard (KDS41) regarding concrete-filled steel tubular structures, established by the architectural institute of Korea in 2005, was revised in 2009 and 2016. The objective was to understand the compressive strengths and deformation capacity of stub columns for concrete-filled square steel tubes under uniaxial compression and validate the KDS41's standard code for necessary corrections. Experiments were conducted on 26 specimens with parameters, such as the width-thickness ratio of cold-formed square tubes. The following values of the stub columns for concrete-filled square steel tubes were obtained: compressive strengths, relationship between the axial load and axial displacement, and failure modes. An analysis of these results enabled an understanding of the concrete-filled effect and the influence of the wide-thickness ratio. The compressive strengths of filled concrete saw a 9% increase compared to a state of uniaxial stress, which must be noted in a future edition of KDS41. After benchmarking the results regarding square steel tubes generated by cold forming to the guidelines provided by the KDS41, the KDS41's value of 2.26 for the limiting width-to-thickness ratio for the compact section was found to be inflated. With a safety concern, this paper proposes a more conservative value of 1.35.

• Journal of Korea Entertainment Industry Association
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• v.15 no.4
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• pp.359-367
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• 2021

This study tried to examine the factors that affect the entrepreneurial intentions in the field of culture and tourism industry. Through this, it was attempted to present strategic implications for start-up plans to prospective entrepreneurs in the cultural tourism industry. As a result of the study, the following implications were drawn. First, prospective entrepreneurs in the field of culture and tourism industry need to analyze the start-up items they want to start and systematically design a start-up plan based on market research. Also, by analyzing various start-up cases, it is necessary to secure various prior experiences of failure and success. Second, prospective entrepreneurs in the field of culture and tourism industry will need to increase their interest in starting a business by completing various entrepreneurship education conducted by more diverse institutions and schools than now, and they will have to increase the sense of achievement and willpower that can appear in education. In addition, by making efforts to create human relationships through various entrepreneurship education, efforts should be made to show the utilization of human networks and information sharing when starting a business. Lastly, prospective entrepreneurs in the field of culture and tourism industry should visit startup-related institutions and receive education and advice from experts in order to acquire various information. In addition, efforts should be made to provide more diverse start-up support by obtaining information on start-ups implemented by the state.

• Korean Journal of Materials Research
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• v.32 no.1
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• pp.9-13
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• 2022

Bullets flying with a light from the back are called "tracers". Tracers are ignited by the combustion gas of the propellant and emit bright light that allows the shooter to visually trace the flight path. Therefore, tracers mark the firing point for allies to assist shooters to hit target quickly and accurately. Conventional tracers are constructed with a mixture of an oxidizing agent, raw metal, and organic fuel. Upon ignition, the inside of the gun can be easily contaminated by the by-products, which can lead to firearm failure during long-term shooting. Moreover, there is a fire risk such as forest fires due to residual flames at impact site. Therefore, it is necessary to develop non-combustion type luminous material; however, this material must still use the heat generated from the propellant, so-called "thermoluminescence (TL)". This study aims to compare the TL emission of Dy³⁺, La³⁺ and Ho³⁺ doped MgB₄O₇ phosphors prepared by solid state reaction. The crystal structures of samples were determined by X-ray diffraction and matched with the standard pattern of MgB₄O₇. Luminescence of various doses (200 ~ 15,000 Gy) of gamma irradiated Dy³⁺, La³⁺ and Ho³⁺ (at different concentrations of 5, 10, 15 and 20 %) doped MgB₄O₇ were recorded using a luminance/color meter. The intensity of TL yellowish (CIE x = 0.401 ~ 0.486, y = 0.410 ~ 0.488) emission became stronger as the temperature increased and the total gamma-ray dose increased.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.1-10
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• 2021

The electro-hydrostatic actuators (EHA) are widely used in various industrial fields since they can independently execute the function of the hydraulic power source and have high efficiency. Particularly, in the aviation field, the EHA is mainly designed as dual redundant asymmetric tandem actuator to mitigate failure and minimize installation space. However, aviation EHAs designed in the form of dual redundant asymmetric tandem actuator have the disadvantage of decreased durability performance due to the occurrence of force fighting. In this paper, the controller is designed based on backstepping technique to improve control performance and reduce force fighting for aviation EHA. The augmented state observer is proposed to estimate the states required for control. Through simulation, it was verified that the proposed controller had superior control performance and significantly reduces the force fighting compared to the general PI controller.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.562-569
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• 2022

The alarm monitoring technology applied to existing operating ships manages data items such as temperature and pressure with AMS (Alarm Monitoring System) and provides an alarm to the crew should these sensing data exceed the normal level range. In addition, the maintenance of existing ships follows the Planned Maintenance System (PMS). whereby the sensing data measured from the equipment is monitored and if it surpasses the set range, maintenance is performed through an alarm, or the corresponding part is replaced in advance after being used for a certain period of time regardless of whether the target device has a malfunction or not. To secure the reliability and operational safety of ship engine operation, it is necessary to enable advanced diagnosis and prediction based on real-time condition monitoring data. To do so, comprehensive measurement of actual ship data, creation of a database, and implementation of a condition diagnosis monitoring system for condition-based predictive maintenance of auxiliary equipment and piping must take place. Furthermore, the system should enable management of auxiliary equipment and piping status information based on a responsive web, and be optimized for screen and resolution so that it can be accessed and used by various mobile devices such as smartphones as well as for viewing on a PC on board. This update cost is low, and the management method is easy. In this paper, we propose CBM (Condition Based Management) technology, for autonomous ships. This core technology is used to identify abnormal phenomena through state diagnosis and monitoring of pumps and purifiers among ship auxiliary equipment, and seawater and steam pipes among pipes. It is intended to provide performance diagnosis and failure prediction of ship auxiliary equipment and piping for convergence analysis, and to support preventive maintenance decision-making.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1082-1087
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• 2021

The propeller shaft has different pattern of behaviors at each static, dynamic, and transient condition to a ship shaft system due to the effects of propeller weight and eccentric thrust, which increases the potential risk of bearing failure by causing local load variations. To prevent this, the various research of the shafting system has been conducted with the emphasis on optimizing the relative slope and oil film retention between propeller shaft and stern tube bearing at quasi-static condition, mainly with respect to the Rules for the Classification of Steel Ships. However, to guarantee a stability of the shafting system, it is necessary to consider the dynamic condition including the transient state due to the sudden change in the stern wakefield during rudder turn. In this context, this study cross-validated the ef ect of propeller shaft behavior on the stern tube bearing during port turn operation, which is a typical transient condition, by using the strain gauge method and displacement sensor for 50,000 DWT medium class tanker. And it was confirmed that the propeller eccentric thrust change showing relief the load of the stern tube bearing.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.21 no.1
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• pp.22-27
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• 2021

Propionic acidemia (PA) is an inherited autosomal recessive disorder, due to the deficiency of propionyl-CoA carboxylase (PCC). PCC is the enzyme which catalyzes the conversion of propionyl-CoA to D-methylmalonyl-CoA, and it is critical for the metabolism of amino acids, odd-chain fatty acids, and side chains of cholesterol. The clinical manifestations present mostly at the neonatal period with life-threatening metabolic acidosis and hyperammonemia. Here, we described a case of a 16-year-old Korean boy with late-onset PA who presented with embolic cerebral infarction due to dilated cardiomyopathy (DCMP) with left ventricular noncompaction. And he has family history of sudden cardiac death, so we performed metabolic screening and genetic tests. Elevated levels of 3-hydroxypropionic acid, methylcitric acid and propionylglycerine were detected in urine. Plasma acylcarnitine profile showed elevated propionylcarnitine (C3). Diagnosis of PA was confirmed by genetic analysis, which revealed compound heterozygous mutations, c.[1151T>G] (p.[Phe384Cys]) and c.[1228C>T] (p.[Arg410Trp]) in PCCB gene. His heart function is in improving state and the results of biochemical analysis are stable with heart failure medication and metabolic managements. We present a case of patient without episodes of metabolic decompensation who manifests DCMP as the first symptom of PA.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.171-182
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• 2022

The safe use of a structure requires it to be maintained in an undamaged state. Thus, a typical factor that determines the safety of a structure is a crack in it. In addition, cracks are caused by various reasons, damage the structure in various ways, and exist in different shapes. Making matters worse, if these cracks are unattended, the risk of structural failure increases and proceeds to a catastrophe. Hence, recently, methods of checking structural damage using deep learning and computer vision technology have been introduced. These methods usually have the premise that there should be a large amount of training image data. However, the amount of training image data is always insufficient. Particularly, this insufficiency negatively affects the performance of deep learning crack detection algorithms. Hence, in this study, a method of augmenting crack image data based on the image translation technique was developed. In particular, this method obtained the crack image data for training a deep learning neural network model by transforming a specific case of a asphalt crack image into a concrete crack image or vice versa . Eventually, this method expected that a robust crack detection algorithm could be developed by increasing the diversity of its training data.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.239-248
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• 2022

The taxonomy of bacteria in the field of clinical microbiology is in a state of constant flux. A large-scale revamping of the classification and nomenclature of anaerobic bacteria has taken place over the past few decades, mainly due to advances in molecular techniques such as 16S rRNA and whole genome sequencing (WGS). New genera and species have been added, and existing genera and species have been reclassified or renamed. A major role of the clinical microbiological laboratories (CMLs) is the accurate identification (ID) and appropriate antimicrobial susceptibility testing (AST) for clinically important bacteria, and rapid reporting and communication of the same to the clinician. Taxonomic changes in anaerobic bacteria could potentially affect the choice of appropriate antimicrobial agents and the antimicrobial breakpoints to use. Furthermore, current taxonomy is important to prevent treatment failures of emerging pathogenic anaerobes with antimicrobial resistance. Therefore, CMLs should periodically update themselves on the changes in the taxonomy of anaerobic bacteria and suitably inform clinicians of these changes for optimum patient care. This article presents an update on the taxonomy of clinically important anaerobic bacteria, together with the previous names or synonyms. This taxonomy update can help guide antimicrobial therapy for anaerobic bacterial infections and prevent treatment failure and can be a useful tool for both CMLs and clinicians.

• Korean Journal of Culture and Social Issue
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• v.16 no.3
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• pp.241-265
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• 2010

This study reviewed the present state and differences of rehabilitation programs of the gambling addiction by comparing with other psychiatric disorder(including psychotic disability and alcohol addiction). This study also intended to suggest necessities, meanings and inherent fields of the rehabilitation in gambling addiction. First of all, the government and a few gambling industries run clinic centers for gamblers and their families, but have been lacked rehabilitation services for social comeback and adaptation or devaluated rehabilitation services than therapies. Gambling addict didn't have impairments of the cognitive function and their daily abilities was better than any other psychiatric disorders. But Damage of social role or function of gambling addiction was severe. And it is caused by nonadaptive nature of gambling behavior, personality/emotional change through gambling addiction process, and previous personality problem etc. There are many severe failure of social role and its attendant bankrupcy, family's problems and social poverty in gambling addiction, Therefore, important fields in the rehabilitation of gambling addiction should be services for basic social comeback support service, credit recovery support, monetary management, support of rehabilitation of family and vocational rehabilitation. Finally, the significance and critical points of the current study has been discussed as well.