• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1013-1022
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• 2022

Recently, with the worldwide development of the fourth industry, the development of technologies for smart and eco-friendly ships is accelerating. With the emergence of autonomous vessels with complete unmanned or minimum personnel on board and eco-friendly fuel (methane, ammonia, electricity, etc.), the role of existing seafarers on board is expected to change significantly. To improve the competitiveness of seafarers in the future, predicting future seafarer occupation groups, improving the educational curriculum, and creating an educational system are necessary. In this study, eight occupational groups that seafarers may have in the future were derived through a review of earlier studies and brainstorming of maritime university students, incumbent seafarers and expert groups. A survey was conducted on the eight occupational groups using the Likert scale, and based on the results, a leading occupational group related to future seafarer was derived. The most likely occupational groups with high scores were remote control centre operators and cargo remote manager. In addition, essential educational elements to be educated first for these occupational groups were derived and presented.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.550-559
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• 2022

Purpose: Pipes are widely used as applied devices in many industrial fields such as machinery, electronics, electricity, and plants, and are also widely used in safety-related fields such as firefighting and chemistry. With the diversification of products, the importance of technology in the piping field is also increasing. In particular, when changing the existing copper pipe to stainless steel, it is necessary to evaluate safety and flow characteristics through structural analysis or flow analysis. Method: This study investigated the safety by flow analysis of the 6.35 inch socket model, which are integrated insert type connectors developed by a company, using CFD analysis technique. For CDF analysis, RAN model and LES model are used. Result: As results of the analysis, amplitude of the pressure fluctuation acting on the wall of the piping system is formed at a level of 3,780 Pa or less, which is a very small level of pressure compared with the operating pressure or design stress of the refrigerant piping. Conclusion: These results mean that the effect of vibration caused by turbulence on the structural safety of the pipe is negligible.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.366-375
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• 2022

The monitoring of electricity consumption using Internet of Things (IoT) technology is attracting attention as a technology to reduce operation costs of smart farms. In this study, we propose a method to apply a real-time electrical consumption monitoring system (the e-Gauge system) and utilization of the collected data real-time while a melon-producing smart farm is in operation. For this purpose, the electrical consumption data for the individual smart-farm facilities such as boilers, nutrient distribution systems, automatic controllers, circulation fans, boiler controllers, and other IoT-related utilities were collected during three months of melon cultivation period. By using the monitoring results, the electrical energy consumption pattern was analyzed as an example, and necessary considerations needed to optimally utilize the measurement data were suggested. This paper will be useful in lowering the technological implementation barriers for new researchers to build a electrical consumption monitoring system and reducing trial and errors in the usage of the generated data.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.1
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• pp.135-140
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• 2022

In addition to the stack that directly generates electricity by the reaction of hydrogen and oxygen, the fuel cell power generation system has a reformer that generates hydrogen from various fuels such as methanol and natural gas. It also consists of a power converter that converts the DC voltage generated in the stack into a stable AC voltage. The fuel cell output of such a system is direct current, and in order to be used at home, an inverter device that converts it into alternating current through a power converter is required. In addition, a DC-DC step-up converter is used to boost the fuel cell voltage to about 30~70V, which is the inverter operating voltage, to about 380V. The DC-DC step-up converter is a DC voltage variable device that exists between the fuel cell output and the inverter. Accordingly, since a constant output voltage of the converter is generated in response to a change in the output voltage of the fuel cell, the inverter can receive constant power regardless of the voltage change of the fuel cell. Therefore, in this paper, we discuss the detailed hardware design of the full-bridge converter, which is the main power source of the inverter that receives the fuel cell output voltage (30~70V) as an input and is applied to the grid among the members of the fuel cell power generation system.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.345-353
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• 2021

Cloud computing represent a new era of computing that's forms through the combination of service-oriented architecture (SOA), Internet and grid computing with virtualization technology. Virtualization is a concept through which every cloud is enable to provide on-demand services to the users. Most IT service provider adopt cloud based services for their users to meet the high demand of computation, as it is most flexible, reliable and scalable technology. Energy based performance tradeoff become the main challenge in cloud computing, as its acceptance and popularity increases day by day. Cloud data centers required a huge amount of power supply to the virtualization of servers for maintain on- demand high computing. High power demand increase the energy cost of service providers as well as it also harm the environment through the emission of CO₂. An optimization of cloud computing based on energy-performance tradeoff is required to obtain the balance between energy saving and QoS (quality of services) policies of cloud. A study about power usage of resources in cloud data centers based on workload assign to them, says that an idle server consume near about 50% of its peak utilization power [1]. Therefore, more number of underutilized servers in any cloud data center is responsible to reduce the energy performance tradeoff. To handle this issue, a lots of research proposed as energy efficient algorithms for minimize the consumption of energy and also maintain the SLA (service level agreement) at a satisfactory level. VM (virtual machine) consolidation is one such technique that ensured about the balance of energy based SLA. In the scope of this paper, we explore reinforcement with fuzzy logic (RFL) for VM consolidation to achieve energy based SLA. In this proposed RFL based active VM consolidation, the primary objective is to manage physical server (PS) nodes in order to avoid over-utilized and under-utilized, and to optimize the placement of VMs. A dynamic threshold (based on RFL) is proposed for over-utilized PS detection. For over-utilized PS, a VM selection policy based on fuzzy logic is proposed, which selects VM for migration to maintain the balance of SLA. Additionally, it incorporate VM placement policy through categorization of non-overutilized servers as- balanced, under-utilized and critical. CloudSim toolkit is used to simulate the proposed work on real-world work load traces of CoMon Project define by PlanetLab. Simulation results shows that the proposed policies is most energy efficient compared to others in terms of reduction in both electricity usage and SLA violation.

• Journal of the Society of Disaster Information
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• v.19 no.1
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• pp.216-230
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• 2023

Purpose: The purpose is to prevent accidents by predicting disasters through the analysis of near-miss. Method: In this study, a near-miss literature review and data were collected at construction sites, and a questionnaire survey was conducted to use logistic regression analysis and decision tree analysis to classify the possibility of near-miss connection. Result: As a result of analyzing the effects of near-miss types on mental, physical, and safety habits and behaviors, the factor with a high influence on the body is the need for near-miss management, the type of job is electricity·information communication, and health status in order, and the mental factor is the construction scale The influence was high, and the factors with the highest influence on the habit behavior factors were analyzed in the order of experience, number of serious injuries, and occupation in order of illusion, inappropriate work instructions, and body parts. Through decision tree analysis, factors and patterns that affect the possibility of a near-miss being a surprise accident were identified. Conclusion: Construction site officials consider the observation of near-miss and mentally and physically. Specific management of the relevance of physical aspects to near-miss should be implemented, and a work environment in which serious accidents are reduced is expected through personnel allocation, work plans, work procedures and methods, and feedback so that inappropriate work instructions do not lead to near-miss.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.169-174
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• 2023

Currently, overall power usage is also increasing as power demand such as homes, offices, and factories increases. The increase in power use also raised interest in standby power as a change in awareness of energy saving appeared. Home and office devices are consuming power even in standby conditions. Accordingly, there is a growing need to reduce standby power, and it aims to have standby power of 1W or less. An intelligent outlet uses a near-field wireless network to connect to a home network and cut or reduce standby power of a lamp or appliance connected to an outlet. This research aims to develop a monitoring system and an intelligent outlet that can remotely monitor the amount of electricity used in a lighting lamp or a home appliance connected to an outlet using a short-range wireless network (Zigbee). Also, The intelligent outlet and monitoring system developed makes it possible for a user to easily cut off standby power by using a portable device. Intelligent outlets will not only reduce standby power but also be applicable to fire prevention systems. Devices that cut off standby power include intelligent outlets and standby power cutoff switches, so they will prevent short circuits and fires.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.289-296
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• 2009

All over the world more and more attention is being paid to green management which enables environment-friendly sustainable development. To keep up with these global trends and in response to the government's "low carbon green growth" policy, many efforts are being made in the port and logistics in order to drastically reduce carbon emissions and save operating expenses. To this end, the engine power source of the cranes in the container terminal is being replaced with electricity from fossil fuel. Among those cranes, especially e-RTGC has been proved to be practical and excellent in its performance through many previous studies. However, no empirical study has yet been made on its introduction effects when e-RTGC has been introduced to the container terminal. In the meantime, however, many domestic container terminals have introduced e-RTGC, and so some data have been accumulated for further research. Under these circumstances, this study has tried to make an empirical study through the case study of D container terminal, checking the restriction factors to be considered at the time of eURTGC introduction, and analyzing its introduction effects and problems. We have high expectations that this study will provide key consideration factors and empirical analysis data to the decision makers who plan to introduce an e-RTGC system, and also will be used as a reference to the development direction of e-RTGC.

• Journal of Industrial Convergence
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• v.21 no.6
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• pp.43-51
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• 2023

This study analyzed the patent status of the outdoor exercise equipment used primarily by the elderly. The purpose is to utilize the basic data obtained to promote the health of the elderly. The information on the patent was collected from KIPRIS, an information search service provided by the Korean Intellectual Property Office. The search term used was 'outdoor exercise equipment', directly related patents were selected, and a final 157 were analyzed. As a result of the analysis, first, patent registration began in 2007, and 2-3 patents were registered on average every year. Second, patents from the perspective of sports convergence that provide an exercise prescription system using wireless communication, such as the ability to generate electricity by operating a power generation module, providing information on the user's exercise amount, or preventing the loss and theft of weights and safety accidents due to their characteristics, were searched for. Lastly, patents related to exercise equipment that can provide user convenience and increase the frequency of use of exercise equipment were searched. The results of this study confirmed that outdoor exercise equipment is being developed more for the elderly and their convenience, and that companies and public institutions are showing increased interest in outdoor exercise equipment for the elderly. In addition to patent trends analysis, follow-up research in connection with exercise programs using outdoor exercise equipment is needed to develop practical and convenient outdoor exercise equipment in the future.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.177-185
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• 2022

In this study, the economic feasibility of a local energy facility that uses forest biomass as an energy source was assessed. We analyzed profitability using data from the Forest Energy Self-sufficient Village Project financed by the Korea Forest Service. The energy facility has a cogeneration generator and wood chip boiler. Wood chip, which has lower heat value and is cheaper than wood pellets, is used as fuel. Revenue comes from the sale of electricity, heat, and renewable energy certificates. Additionally, we considered the sale of carbon credits as substitutes for fossil fuels. The expenditure consists of fuel costs and fixed costs, and the initial investment is treated as a sunk cost. Under the condition of a 55% operation rate and wood chip price of 95,000 KRW per ton, the annual net revenue is positive. Crucial factors for managing the facility sustainably are operation rate and fuel cost. A simulation in which two factors were changed showed that the annual net revenue is negative with a 50% operation rate and 100,000 KRW per ton of wood chip price. To improve net revenue, an increase in the operation rate or a decrease in the wood chip price is required. Additionally, selling carbon credits will make the operation of the facility more profitable. Furthermore, the payment required to procure wood chips could contribute to the rural economy. To foster the use of forest biomass for energy, the price for heat supplied from renewable energy sources should be subsidized.