• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.33 no.5
• /
• pp.196-201
• /
• 2023

In order to improve the efficiency of the water splitting system for hydrogen energy production, the high overvoltage in the electrochemical reaction caused by the catalyst in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be reduced. Among them, transition metal-based compounds (hydroxide, sulfide, etc.) are attracting attention as catalyst materials to replace currently used precious metals such as platinum. In this study, Ni foam, an inexpensive metal porous material, was used as a support and β-Ni(OH)₂ microcrystals were synthesized through a hydrothermal synthesis process. In addition, changes in the crystal morphology, crystal structure, and water splitting characteristics of β-Ni(OH)₂ microcrystals synthesized by doping Fe to improve electrochemical properties were observed, and applicability as a catalyst in a commercial water electrolysis system was examined.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.5
• /
• pp.108-126
• /
• 2023

In this paper, the dynamic hard shoulder running for bus only (HSRFBO) was presented to solve the traffic congestion by increase the capacity in chronic congested sections of highways, and a simulation was performed to evaluate the comparison with the current hard shoulder running for all vehicles(HSRFAV) and median bus only lane and HSR(MBOLHSR). According to the evaluation results, it was evaluated to be more advantageous in terms of traffic flow and safety than the current HSRFAV. In addition, the speed of passing buses is slightly reduced compared to the MBOHSR, but the speed of entering and exiting buses is increased and the speed of buses and cars is greatly improved. Therefore It was analyzed that the efficiency of transport personnel was also improved. In particular, it is expected that traffic flow will be stabilized as the difference in speed between passenger cars and buses will be greatly reduced, and violations of exclusive bus lanes by passenger cars will be greatly reduced. In addition, the operation time of HSR is greatly reduced, so that the original function of the shoulder lane can be maintained as much as possible. As a result, it was analyzed that the risk of accidents was significantly reduced when operating HSRFBO compared to when operating MBOHSR, and cross-conflicts with high accident severity did not occur.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.5
• /
• pp.21-27
• /
• 2023

As a means of helping ships navigate safely, navigational aids in operation in the maritime envirionment require periodic management, and due to the nature of the environment, it is difficult to visually check the exact state. As a result, the smart navigation aid system, which improves route safety and operational efficiency, utillizes expertise including sensors, communications, and information technology, unlike general route markings. The communication environment of the smart navigation aid system, which aims to ensure the safety of the navigators operating the ship and the safety of the ship, uses a wireless communication network in accordance with the marine environment. The ship collects the information necessary for the maritime environment on the land and operates. In this process, there is a need to consider the wireless communication security guideline. Basically, based on IHO S-100 a standard for facilitating data exchange and SECOM, which provides an interface for safe communication. This paper research a security system for safe communication in a maritime environment. The security system for the basic interface based on the document was presented, and there were some vulnerabillties to data exchange due to the wireless communication characteristics of the maritime environment, and the user authetication part was added considering the vulnerability that unauthorized users can access the service.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.6
• /
• pp.666-671
• /
• 2023

As international environmental regulations on ship emissions are gradually strengthened, interest in electric propulsion and hybrid propulsion ships is increasing, and various solutions are being developed and applied to these ships, especially stabilization of the power system and system efficiency. The direct current distribution system is being applied as a way to increase the power. In addition, verification and testing of safety and performance of marine DC distribution systems is required. As a result of establishing a DC distribution test bed, verifying the performance of the DC distribution (variable speed power generation) system, and analyzing fuel consumption, this study applied a variable speed power generation system that is applied to DC power distribution for ships, and converted the power output from the generator into a rectifier. A system was developed to convert direct current power to connect to the system and monitor and control these devices. Through tests using this DC distribution system, the maximum voltage was 751.5V and the minimum voltage was 731.4V, and the voltage fluctuation rate was 2.7%, confirming that the voltage is stably supplied within 3%, and a variable speed power generation system was installed according to load fluctuations. When applied, it was confirmed through testing that fuel consumption could be reduced by more than 20% depending on the section compared to the existing constant speed power generation system.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.6
• /
• pp.1127-1134
• /
• 2023

This study is a qualitative study to uncover the meaning and structure of nursing students' online psychiatric nursing practice experience by applying Parse's research method. The subjects of the study were 9 fourth-year nursing students at K University who took psychiatric nursing practice online in the COVID-19 situation. Data collection was conducted from March 7, 2022 to May 27, 2022. As a result of the study, the core concepts of nursing students' online practice experience in psychiatric nursing in the COVID-19 situation were: 'Recognizing the importance of understanding oneself and others', 'Preparing for communication to build therapeutic relationships', and 'A perspective on the future through exploration of the meaning of nursing'. Structural transposition was presented as 'Empathy for self and others', 'Mindset for interpersonal human relationship', 'Exploring the essence of nursing and self-realization'. Conceptual integration appeared as 'Valuing', 'Revealing-Concealing', 'Revealing-Concealing'. In conclusion, nursing students' online practice experience in mental health nursing in the COVID-19 situation was an experience of growing and transcending as future nurses by recognizing the importance of human understanding and communication for the therapeutic relationship that is the purpose of mental nursing. This study will serve as basic data for efficient clinical practice operations in various unpredictable situations, such as future pandemics.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.6
• /
• pp.867-873
• /
• 2023

In this study, for the purpose of standardized quality control of a cold medicine, we simultaneous analyzed four main chemical components of a cold medicine: acetaminophen, caffeine, methyl paraben, and propyl paraben. The sample was subjected to quantitative analysis using high performance liquid chromatography (HPLC), after pretreatment of four components. The experiment was carried out by using Isocratic elution at wavelength of 270nm. Acetonitrile and water (H₂O) were used as a mobile phase at a flow rate of 1.0mL/min in a commercial C18 reversed-phase column. A volume of 10uL cold medicine were injected into the column with column oven temperature at 35℃. As a result of the experiment, the values of Resolution were 4.983, 1.596, 5.519, and 1.678 respectively-well over Rs >1.5, which indicates that the separation of four components were efficient. In addition, value of symmetry factor of the components was 1.056, 1.069, 1.032, and 1.133 respectively, to show its symmetrical stability. The calibration curve of all four components exhibits good linearity with R² >0.9995 to 0.9999. Furthermore, the limit of detection(LOD) were between 0.0118 to 1.5973 mg/mL, while the limit of quantification (LOQ) were between 0.0353 to 4.7919 ㎍/mL with the recovery rate of 79.6% ~ 120.5%. The results of this study showed an efficient quality evaluation of a simultaneous analysis method for cold medicine components.

• Journal of the Korea Institute of Building Construction
• /
• v.23 no.5
• /
• pp.607-618
• /
• 2023

Pervasive research underscores the direct correlation between an enhanced safety climate and a marked reduction in accidents. The intricacies of safety climate are governed by three pivotal strata: organizational management, on-site operations, and the broader enterprise framework. Within an organizational context, sustaining optimal performance across these layers poses a considerable challenge, often attributable to the constraints of available managerial bandwidth. It becomes imperative, then, to conceive a phased enhancement blueprint for the safety climate. To orchestrate this blueprint with precision, a discerning understanding of the hierarchy of safety climate metrics is essential, which subsequently guides judicious managerial resource allocation. This investigation is anchored in elucidating the hierarchical significance of safety climate metrics through the Analytical Hierarchy Process(AHP). Implementing the AHP framework, both a questionnaire was disseminated and a subsequent analysis undertaken, culminating in the extraction of relative priorities of safety climate determinants. Consequent to this analysis, "workers' safety prioritization and risk aversion" emerged as the foremost dimension, holding a significance weight of 0.1900. Furthermore, within the detailed elements, "unwavering adherence to safety mandates amidst demanding operational constraints" ranked supreme, manifesting a weight of 0.6663. The findings encapsulated in this study are poised to be foundational in sculpting improvements at an institutional level and devising policies, all with the end goal of fostering an exemplar safety climate within construction arenas.

• Journal of the Institute of Convergence Signal Processing
• /
• v.24 no.2
• /
• pp.126-133
• /
• 2023

In this study, electromyography was obtained in the six muscle areas that move the joints of the two legs, and by analyzing it, an exercise robot system capable of gait rehabilitation was proposed in consideration of the individual's muscle state. Through this, the system was constructed to prevent the effect of exercise from decreasing because the patient's will was not reflected when walking exercise was simply provided automatically. As a result of the evaluation of the developed system, it was confirmed that the pedestrian rehabilitation robot system manufactured through this study had performance suitable for the design requirements, and it was also confirmed that the usability evaluation was comprehensively satisfactory. The results of this study are thought to be of great help to patients who are having difficulty in gait rehabilitation, and are believed to be helpful in the development of electromyography signal-based gait robot systems.

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

• Journal of the Korean Institute of Gas
• /
• v.27 no.3
• /
• pp.1-10
• /
• 2023

Due to the development of the industrial revolution, regulations on exhaust emissions have been continuously strengthened to reduce the rapidly increasing greenhouse gas emissions. The use of environmentally friendly fuels is essential to meet these regulations. Hydrogen has been attracting attention as a future environmentally friendly fuel, but due to its material properties, it faces significant challenges in handling and storage. As an alternative, ammonia has been proposed. Ammonia can be easily liquefied at room temperature compared to hydrogen and has a high energy density. In order to examine the applicability of ammonia as an engine fuel, experiments were conducted to investigate the effects of changes in combustion control parameters in a direct injection ammonia combustion engine. The experiments were conducted by varying two variables: spark timing and excessive air ratio. Observations were made on combustion stability and the trends of exhaust emissions such as nitrogen oxides and unburned ammonia under the conditions of an engine speed of 1,500 rpm and medium to high loads (brake torque of 200 Nm). By optimizing the combustion control parameters, conditions for stable combustion even when using ammonia as the sole fuel were identified, and plans are underway to apply strategies for future expansion of the operating range.