• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.57-62
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• 2021

In this study, risk assessment was conducted in case of leakage of storage facilities (tube trailer) using the HyKoRAM program developed through international joint research. The high-pressure gas facilities in the hydrogen filling station are divided into four main categories: storage facilities (tube trailers), processing facilities (compressors), compressed gas facilities, and filling facilities (dispensers). Among them, the design specifications of the tube trailer, which is a storage facility, and the surrounding environmental conditions were reflected to construct an accident scenario with previously occurring accidents and potential accidents. Through this, we identify the risks of storage facilities at hydrogen refueling stations and suggest measures to improve the safety of hydrogen charging stations.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.43-48
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• 2021

This study was conducted using FLACS, a specialized gas accident analysis program. Hydrogen refueling stations subject of safety analysis, consist of compression facilities, storage tanks, and hydrogen piping. The safety analysis of potential risk factors was conducted after reflecting the design specifications of major facilities and components, environmental conditions around hydrogen refueling stations, etc. As of 2021, about 70 refueling stations in Korea are available, and 1,200 are scheduled to be introduced in the next 2040. To prepare for possible accidents caused by potential hazards for the safe distribution of hydrogen refueling stations, we intend to derive hydrogen leakage diffusion scenarios and review their safety.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3580-3596
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• 2021

An integral test facility, PILLAR, was commissioned, aiming to provide valuable experimental results which can be referenced by system and component designers and used for the performance demonstration of liquid-metal-cooled, passive small modular reactors (SMRs) toward their licensing. The setup was conceptualized by a scaling analysis which allows the vertical arrangements to be conserved from its prototypic reactor, scaled uniformly in the radial direction achieving a flow area reduction of 1/200. Its final design includes several heater rods which simulate the reactor core, and a single heat exchanger representing the steam generators in the prototype. The system behaviors were characterized by its data acquisition system implementing various instruments. In this paper, we present not only a detailed description of the facility components, but also selected experimental results of both steady-state and transient cases. The obtained steady-state test results were utilized for the benchmark of a system code, achieving a capability of accurate simulations with ±3% of maximum deviations. It was followed by qualitative comparisons on the transient test results which indicate that the integral system behaviors in passive LBE-cooled systems are able to be predicted by the code.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.637-657
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• 2021

While the conventional vehicle's Head-Units played relatively simple roles (e.g., control of heating ventilation and air conditioning, the radio reception), they have been evolving into vehicle-driver interface with the advent of the concept of Connected Car on top of a rapid development of ICT technology. The Head-Unit is now successfully extended as an IVI (In Vehicle Infotainment) that can operate various functions on multimedia, navigation, information with regards to vehicle's parts (e.g. air pressure, oil gauge, etc.). In this paper, we propose a platform architecture for IVI devices required to achieve the goal as a connected car. Connected car platform (CoCaP) consists of vehicle selective gateway (VSG) for receiving and controlling data from major components of a vehicle, application framework including native and web APIs required to request VSG functionality from outside, and service framework for driver assistance. CoCaP is implemented using Tizen IVI and Android on hardware platforms manufactured for IVI such as Nexcom's VTC1010 and Freescale's i.MX6q/dl, respectively. For more practical verification, CoCaP platform was applied to an real-world finished vehicle. And it was confirmed the vehicle's main components could be controlled using various devices. In addition, by deriving several services for driver assistance and developing them based on CoCaP, this platform is expected to be available in various ways in connected car and ITS environments.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.171-171
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• 2016

최근 도시화가 진행되면서 지표의 불투수화가 급격하게 진행되고 강우의 지표면 유출량이 급격하게 증가하여, 강수 시 첨두유출 시간이 감소하고 단기간 집중유출이 증대되어 폭우로 인한 도시 홍수등이 발생하고 있다. 이러한 현상에 효과적으로 적응하기 위해 환경적으로 지속가능한 도시 개발을 위한 그린인프라(GI, Green Infrastructure) 및 저영향개발기법(LID, Low Impact Developpment)이 국내에 도입되고 있다. 하지만 아직까지 투수성 포장의 물순환 성능 평가 및 설계 방법에 대한 기준이 명확하지 않으며, 많은 경우 투수성 포장의 적용은 유출저감효과에 대한 정량적 해석 없이 적용되고 있는 실정이다. 이에 본 연구에서는 경남 양산시 부산대학교 제 2 캠퍼스에 있는 "한국형 GI&LID 실증실험단지"에 투수 도로형 실증실험시설을 구축하였다. 실험 시설은 불투수 아스팔트와 투수 아스팔트, 불투수 콘크리트와 투수 콘크리트 비교실험 할 수 있으며 도로표면 유출수 및 침투수에 대한 유량 및 수질 측정 모니터링을 통해 침투효과 및 특성을 분석할 수 있으며 차후 투수성 포장의 클로깅 현상으로 인한 투수성능의 감소 등 여러 가지 실험을 할 수 있을 것이다.

• The Journal of Economics, Marketing and Management
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• v.9 no.2
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• pp.21-31
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• 2021

Purpose: This study aims to provide marketing implications for training and face-to-face service employee communication by analyzing how communication by Korean crews at foreign airlines affects passengers' perception and how this perception relates to airline service quality and customer satisfaction. Research design, data: The collection of questionnaires for the demonstration in this study has collected 300 questionnaires for about a month for Korean passengers who are aware of the presence of Korean crew on board aircraft. Results: The study analyzed the relationship between the communication ability, customer satisfaction, and reuse intention of foreign airlines. An empirical analysis of the relationship between quality of airline service, customer satisfaction, and intention of re-use can suggest the following implications based on the language and non-verbal communication capabilities of the Korean crew working for foreign airlines. Conclusions: We studied the impact of communication between Korean crews working for foreign airlines on the quality of airline service, customer satisfaction and reuse intention. The Korean crew should also work for overseas airlines and consider communication as important and expand their overall foreign language education and communication skills to have a positive impact on not only Korean passengers but also their own citizens.

• The Journal of Information Systems
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• v.31 no.2
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• pp.217-238
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• 2022

Purpose This study aims to develop a work-related injury and illness monitoring geographic information system that analyzes and visualizes the types of work-related injury and illness based on workers' compensation insurance big data. Design/methodology/approach Using the developed system, we explained the process of monitoring the areas of the applied workplace, medical care application, index, and medical care institution. We also showed examples of analyzing the index and medical care institution area. By applying the system, we can intuitively recognize the current status of workers' compensation insurance and confirm the basic information necessary for managing the current status of workers' compensation insurance. Findings We generated more helpful information by combining workers' compensation insurance data and designated medical care institution data. We were able to apply the severity score and the vulnerability index of work-related injury and illness to the system as a demonstration. To efficiently manage workers' compensation insurance, it was necessary to integrate workers' compensation insurance and designated medical care institution data, as well as the data from various sources.

• Geomechanics and Engineering
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• v.30 no.5
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• pp.449-460
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• 2022

Safe underground construction in a rock mass requires adequate ground investigation and effective determination of rock conditions. The estimation of rock mass behavior is difficult, because rock masses are innately anisotropic and heterogeneous at different scales and are affected by various environmental factors. Quantitative rock mass classification systems, such as the Q-system and rock mass rating, are widely used for characterization and engineering design. The measurement of rock classification parameters is subjective and can vary among observers, resulting in questionable accuracy. Geophysical investigation methods, such as seismic surveys, have also been used for ground characterization. Torsional shear wave propagation characteristics in cylindrical rods are equal to that in an infinite media. A probabilistic quantitative relationship between the Q-value and shear wave velocity is thus investigated considering long-wavelength wave propagation in equivalent continuum jointed rock masses. Individual Q-system parameters are correlated with stress-dependent shear wave velocities in jointed rocks using experimental and numerical methods. The relationship between the Q-value and the shear wave velocity is normalized using a defined reference condition. This relationship is further improved using probabilistic analysis to remove unrealistic data and to suggest a range of Q-values for a given wave velocity. The proposed probabilistic Q-value estimation is then compared with field measurements and cross-hole seismic test data to verify its applicability.

• Journal of Wellbeing Management and Applied Psychology
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• v.6 no.3
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• pp.19-23
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• 2023

Purpose: High concentrations of nitrogen exist in food wastewater, and when nitrogen is not properly treated and discharged, it can cause eutrophication in the aquatic ecosystem. Research design, data and methodology: In order to remove nitrogen using sodium hypochlorite, the BNCR tank was designed and installed in the step behind the biological treatment tank, and the data of pH, TOC, and T-N were collected after about a month of demonstration. Results: As a result of operating the BNCR tank, total nitrogen decreased by about 83% on average. The total nitrogen in the second sedimentation tank before going through the BNCR tank must be removed and finally discharged after nitrogen is removed above the legal standard of 60 mg/L. Conclusions: If BNCR tank is added to the process currently applied to nitrogen removal and operated, ammonia nitrogen can be removed more efficiently. However, the disadvantage is that nitric acid nitrogen and nitric acid nitrogen cannot be removed. If these disadvantages are supplemented and optimized in the future, it will be helpful for workplaces that are having difficulty removing nitrogen.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.523-533
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• 2022

Several prediction model of penetration rate (PR) of tunnel boring machines (TBMs) have been focused on applying to design stage. In construction stage, however, the expected PR and its trends are changed during tunneling owing to TBM excavation skills and the gap between the investigated and actual geological conditions. Monitoring the PR during tunneling is crucial to rescheduling the excavation plan in real-time. This study proposes a sequential prediction method applicable in the construction stage. Geological and TBM operating data are collected from Gunpo cable tunnel in Korea, and preprocessed through normalization and augmentation. The results show that the sequential prediction for 1 ring unit prediction distance (UPD) is R²≥0.79; whereas, a one-step prediction is R²≤0.30. In modeling algorithm, a gradient boosted regression tree (GBRT) outperformed a least square-based linear regression in sequential prediction method. For practical use, a simple equation between the R² and UPD is proposed. When UPD increases R² decreases exponentially; In particular, UPD at R²=0.60 is calculated as 28 rings using the equation. Such a time interval will provide enough time for decision-making. Evidently, the UPD can be adjusted depending on other project and the R² value targeted by an operator. Therefore, a calculation process for the equation between the R² and UPD is addressed.