• Ocean and Polar Research
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• v.45 no.2
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• pp.33-42
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• 2023

Dissolved oxygen (DO) is a crucial parameter for assessing environmental conditions in aquatic ecosystems. However, commercial in situ dataloggers for oxygen optodes can be relatively expensive and limited in their specifications. In this paper, we present a novel design for a DO datalogger system based on the control boards family with RP2040 MCU chipset. Our design includes two types of dataloggers: a simple logging system and a programmable system for sampling rates via magnetic switches underwater for divers. We provide detailed descriptions of the system, including the MicroPython source code and drawings to aid in construction. We also discuss the various applications of our DO datalogger system in monitoring dissolved oxygen concentration in coastal waters and assessing the benthic metabolism of aquatic ecosystems. Our DO datalogger system provides an affordable and flexible option for researchers to accurately monitor DO concentrations in aquatic environments, and thereby improve our understanding of these complex ecosystems.

• Journal of ILASS-Korea
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• v.27 no.1
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• pp.11-17
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• 2022

In upcoming Post Stage-V and Tier 5 regulations of construction machineries, nitrogen oxide (NOx) emissions are strictly limited in cold start conditions. In response to this, a method of improving NOx conversion efficiency has been applied by installing an electric heating catalyst (EHC) in front of conventional urea-SCR systems so that the evaporation and thermal decomposition of urea-water solution can be promoted in cold start conditions. In this strategy, the evaporation and thermal decomposition of urea-water solution and corresponding NOx conversion efficiency are governed by temperature conditions inside the EHC. Therefore, characterizing the temperature distribution in the EHC under various operating conditions is crucial for the optimized operation and control of the EHC in Urea-SCR systems. In this study, a 1-D modeling analysis was performed to predict the heater surface temperature distribution in EHC under various operating conditions. The reliability of prediction results was verified by comparing them with measurement results obtained using an infrared (IR) camera. Based on 1-D analysis results, the effects of various EHC operation parameters on the heater surface temperature distribution were analyzed and discussed.

• Journal of Drive and Control
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• v.19 no.2
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• pp.36-44
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• 2022

Hydrogen energy as an alternative source of energy has been receiving tremendous support around the world, and research is being actively conducted accordingly. However, most of the studies focus on hydrogen storage tanks and only are few studies on interpreting the hydrogen filling system itself. In this study, with reference to SAE J2601, a hydrogen fueling protocol, a simulation model was developed that can confirm the behavior of the vehicle's internal tank during hydrogen fueling. With respect to factors such as fuel supply temperature, ambient temperature, and pressure increase rate, the developed model can check the change of temperature and pressure in the tank and the state of hydrogen charging during hydrogen fueling. The validity of the developed simulation model was confirmed by comparing the simulation results with the experimental results presented in SAE J2601.

• Geomechanics and Engineering
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• v.33 no.4
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• pp.353-367
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• 2023

The construction of a protective embankment is a suitable strategy to stop and control high-energy rock blocks' impacts during the rockfall phenomenon. In this paper, based on the discrete element numerical method, by modeling an existing embankment reinforced with geogrid, its stability status under the impact of a rock block with two types of low and high kinetic energy, namely 2402 and 4180 kJ, respectively, has been investigated. The modeling results show that the use of geogrid has caused the displacement in the front and back of the embankment to decrease by more than 30%. In this case, the reinforced embankment has stopped the rock block earlier. The displacements obtained from the DEM modeling are compared with the displacements measured from an actual practical experiment to evaluate the results' validity. Comparison between the results shows that the displacement values are close together, while the maximum percentage error in previous studies by an analytical method and the finite element method was 76.4% and 36.6%, respectively. Therefore, the obtained results indicate the discrete numerical method's high ability compared to other numerical and analytical methods to simulate and design the geogrid-reinforced soil embankment under natural disasters such as rockfall with a minor error.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.2
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• pp.9-13
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• 2023

Purpose: In this study, we would like to make a technical proposal to solve the odor problem in pig houses. Through this, we would like to suggest an effective way to reduce the odor generated in the pig house as a solution to civil complaints. Research design, data and methodology: Conduct direct visits to pig farms where many civil complaints about bad odor occur, and identify the problems of each farm. Identify elements related to odor control, such as structure, facility, equipment, odor management method, and ventilation type. Through this, the technology to be applied to reduce odor and the solution to the odor problem are presented. Results: The results of major improvements are as follows: 1. Improvement of the structure of the barn or composting shed to an airtight type 2. Improvement of the pig manure treatment structure using the slope inside the barn 3. Establishment of ventilation and cooling systems 4. Automation of the mist spray system. Conclusions: As a result, as practical measures, sealing of facilities using winch curtains, construction of air conditioning systems using negative pressure ventilation, and management systems using AIoT systems were presented. It is judged that this study can be helpful in determining the grievances caused by civil complaints of tenant livestock farms and the direction of facility improvement in the future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.283-284
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• 2021

The domestic and overseas IoT (Internet of Things)-based automation industry is developing remarkably, and the development of this automation technology is further accelerated by the development of sensor technology. In recent years, the smart farm industry for the purpose of growing crops based on various sensor technologies is rapidly developing. In the case of smart farms, real-time monitoring and mobile services are provided by measuring representative environmental data such as temperature, humidity, and CO2 required for crop cultivation. Most of these environmental monitoring and control operations use the RS-485-based Modbus (RTU) communication method. In this paper, we intend to test the performance of sensor data and actuator information required for smart farm construction by building a platform for controlling sensor data and actuators based on LabView using MQTT (Message Queuing Telemetry Transport), an IoT standard protocol.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.2
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• pp.107-115
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• 2009

Lately, the length of tunnel, the number of large-long tunnel over three lanes are steeply increased because of the request for high speed and straight road. Therefore, the maximization of excavation efficiency is needed in tunnel construction. Bulk Emulsion explosives charging system is the spearhead equipment using the radio remote control $&$ mechanization system compare with a traditional method Cartridge type. This study introduced the bulk emulsion explosives which is new method in tunnel blasting and verified the efficiency of bulk emulsion explosives for long-large tunnel. And we tried to compare Cartridge type efficiency with bulk emulsion explosives efficiency by the field test.

• The Journal of Economics, Marketing and Management
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• v.6 no.1
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• pp.1-8
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• 2018

Purpose - Local social commerce market has grown up remarkably. And, Coupang has shown new delivery strategy of rocket delivery. Making new paradigm at local market, Coupang has expanded market scale. This study investigated state of local social commerce market, weight and promotion strategy of Coupang market to find out competitiveness edge of Coupang. Research design, data, and methodology - The study investigated state and concept of social commerce to find out state, problems and competitiveness of social commerce. New distribution service was short of precedent studies. Statistical analysis and experimental analysis were not used, and interview was done to investigate three of social commerce businesses. Results - CRM construction is insufficient to have poor system, Local delivery system could not be made enough at overnight delivery and customers were dissatisfied with ties with another company. Promotion shall be done by delivery system for increase of profitability, funding for more investment, chatbot to build new customer control system, and new delivery system to produce profit. Conclusions - Coupang and others have grown up rapidly to worsen profit and to jeopardize survival. Excessive initial investment has threatened the businesses, for instance, low sales of Amazon, excessive expenses, bench marking of logistics system, and others.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.276-276
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• 2022

Estuarine dams are constructed for securing freshwater resources, flood control, and improving upstream navigability. However, their impact on estuarine currents, stratification, and sediment fluxes is not well understood. To develop a general understanding, an idealized modeling study was carried out. Tide and river forcing were varied to produce strongly stratified, partially mixed, periodically stratified, and well-mixed estuaries. Each model ran for one year. Next, the models were subject to the construction of an estuarine dam and run for another year. Then, the pre- and post-dam conditions were compared. Results showed that estuarine dams can amplify the tidal range and reduce the tidal currents. The post-dam estuaries tended to be a salt wedge during freshwater discharge and a bay during no freshwater discharge. For all estuaries, the estuarine turbidity maximum moved seaward, and the suspended sediment concentrations tended to decrease. In terms of sediment flux mechanisms, the estuarine dam increased the seaward river runoff for cases with strong river, and increased the landward tidal pumping for cases with strong tides.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.646-649
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• 2022

Media is a means for exchanging one's emotions or objective information in human society. Due to the spread of smart media due to the advent of digital media, media in modern society is not a simple means but encompasses the entire society in which humans live. It even took over the control function. Therefore, by examining the types and characteristics of media according to the service platform in which smart media is used, and building a big data hub for media based on this, new development and research directions for digital media can be explored. In this paper, we analyze various metadata generated through smart media and propose a plan for building a big data platform using it.