• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.3
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• pp.298-309
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• 2019

Objectives: This study aimed to investigate stages of safety and health culture change through a reflection on 40 years of hearing conservation history at a multinational company. Methods: The target workplaces were multinational companies with more than 1,000 employees. The research used the clinical case study and system analysis methods based on direct observation of the research from 1994 to 2009. The latter method performed an analysis of the equilibrium state of the cross-section in the given period and the longitudinal profile of the change during the given period. Results: The stages of cultural change are divided into five stages and summarized as follows. In the first stage, workplace noise was not widely recognized as a hazard, while in the second stage, the measurement of noise levels and audiometric testing were conducted under the Korean Occupational Safety and Health Act (KOSHA). The driving force for change in the second stage was the amendment of the KOSHA. In the third stage, noise came to be recognized as a hazard factor through awareness training. The driving force of change during the third stage was the strong executive power exerted by the audit of the industrial hygiene program from the US head office. In the fourth step, there was a change to actually reduce noise. The driving force in this stage was a change in company executives' risk perception resulting from lawsuits over noise-induced hearing loss and the task force team activities for culture change based on the action learning protocol. At the fifth stage, a 'buy quiet policy' was institutionalized. The management's experience that noise reduction was difficult was the motivation to manage noise from the time of purchase of equipment. Conclusions: The activities of a hearing conservation program are determined by the improvement of the legal system and by the way it is enforced. Noise control activities to reduce noise areas may be possible through the shared risk perception of noise-induced hearing loss and by a change agent role as a facilitator to implement noise control.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.2
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• pp.113-127
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• 2021

Although planning techniques linking parks, green areas, and waterways have become common, there are frequent disruptions in the operation and management of landscape-use artificial channels (LuAC). Therefore, this study examined a design to promote the sustainable management and operation of a LuAC using rainwater for the streamlets of the Jeonju-Wanju Innovative City. In order to accomplish the purpose of this study, scenarios were set up by dividing the design into waterhead and waterway portions. First, the scenario regarding the waterhead was analyzed to calculate the water supply and storage required for the waterway and waterhead. The analysis showed that the waterway requires a water supply of 676.8 tons/months, 3,018 tons to 5,512 tons of storage space, and a water depth of 0.75 m to 1.37 m considering the ecological and landscape aspects. The second scenario is to select an effective system of facilities for the operation and management of the LuAC. To accomplish this, a single-circulation system (SCS), which transports water to a highland location was compared to a multi-circulation system (MCS), which supplied water separately to each water space and operated independently. The results showed that the MCS, which was operated independently by small power units, was more effective owing to the vast difference in water supply operation times.

• Journal of vocational education research
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• v.33 no.3
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• pp.145-167
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• 2014

The purpose of this research is to prepare the measures for evaluating the job of horse-riding instructor and improvement related to it and for distributing horse-riding industry effectively. Forsuch, we tried to analyze job of horse-riding instructor. Inparticular, we have developed DACUM chart of horse-riding instructor through DACUM method and experts related to it. As result, we found out eight duties and hundreds of job and arranged seven duty areas in total and eighty-two executed works. In addition, as experts said, the horse-riding instructor is the one who 'instructs people learning horse-riding in horse-riding facility and manages horses, horse-riding equipment and man-power.' Such results provide the procedure of horse-riding instructor cultivation which has been presently underway with many viewpoints. Especially, there are three educational processes and subject materials related to horse-riding instructor's examination(Hipologia, Horse-treatment technique, Horse Health management). However, as result of analysis on duty, we found out that racecourse management and horse-riding education theory has been needed to be added and complemented as well. In addition, the work and duty of analysis can be used to be made use up of as work profile and specification and such data can be also made use of as standard of training and submission. Through this study there should be a necessary work to distinguish between re-drafting and role of duty in its own right related to certification of horse-riding instructor in future and it would be necessary to develop study that is able to connect them all to certificate. What is more, there should be work and measure required for rethinking of utility of certification.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.282-289
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• 2019

Reflective and solar LED road studs are being used as a way of securing visibility for road environments. Road markers have various advantages and disadvantages in terms of versatility, efficiency, simplicity and visibility as individual products of reflective type and solar LED. However, in addition to the above, it is possible to prevent secondary accident after accident, It has a common drawback that it is difficult to have. In this paper, we propose a road stud system incorporating a wireless control function using RF - based communication with existing solar LED road studs and a system for controlling them. The proposed system is called the smart road stud system and it can control the equipment through the central control unit and the relay unit connected to the central control room by incorporating the RF communication function in the existing solar LED road stud. In addition, since it is possible to control the lighting method, color, etc. according to the road condition, it is possible to provide the driver with the state of the road to perform the function for preventing the second accident after the accident. It also adds features that minimize the ongoing power consumption of LED and RF communications. In order to verify the validity of the proposed system, prototypes were produced and it was confirmed that it is possible to act as a university for prevention of accident after accident by linking with other traffic system besides accident prevention function by securing existing visibility.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.233-241
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• 2018

Recently, integrated railway safety monitoring and control system, which is a convergence system based on data distribution service for railway safety monitoring and control, is under development. It collects safety data of vehicle, signal, power and safety monitoring facilities in real time and adopts communication middleware based on distributed service for mass data processing. However, in the case of a server device used as an existing control server, the performance of the distributed service middleware can not be exhibited due to low hardware performance due to safety reasons. In the safety control system, 200,000 packets per second were set as the transmission target, but the performance test of the LAB was not satisfied. In this paper, we analyze the characteristics of railway data to improve the data collection performance of existing equipment and apply DDS-based streaming transmission method to the data model of signal facilities and vehicle facilities with large packet amount according to the analysis result. As a result, it was confirmed that the throughput was improved about 30.4 times when the hardware performance was the same. We plan to improve the data processing performance by applying it to real-time railway safety integrated monitoring and control system in the future.

• Korean Journal of Heritage: History & Science
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• v.42 no.4
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• pp.4-19
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• 2009

Though admitting that, in light of the recent archaeological trend, the excavation on relics of Sam-gama (a sort of kiln steaming the hemp) is increasingly reported, little efforts by far have been made not only to restore its traditional structure design but also to research hardly the change of hemp-steaming technologies in ages. In this regard, this paper shows the exploration of structural method and design as well as operability with regard to Sam-gut, traditional hemp-processing equipment that was recently reconstructed in Jungsun, Kangwon Province. Samgut, generally positioned at the waterside area, is an traditional device for steaming hemp to get bast fibers from the raw material of hemp, principally consisting of HWA-JIP(fire-place) to obtain steams by feeding fire ad Mong-got(boiling chamber) to make the hemp steamed after stacking. More specifically, thick round-logs were piled at the bottom of Hwajip prior to stacking stones around its circumferential area. When the timber positioned below gets burned with high temperature to heat stones existing in the upper side, waters then poured onto it after laying a bundle of grass and soil up to the boiled stones. If so, there generates hot vapor, which is conveyed to Monggot to steam the hemp. Functionally, it is of outstanding importance that Samgut is capable of producing high-temperature water vapors instantaneously under the intensive manpower, thus being constructed achievable for those purposes. The Samgut made by digging the ground is an instant facility that is closed after use. The remains, which were used to generate higher thermal power for steaming hemp, make it hard to excavate the historic traits because there left little vestiges in the soil, which means keen attention must be paid to find out the trace of Smgama relics. Future research stall be focused on collection of broader data regarding Samgut including technological review in extracting bas fibers from the hemp.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.172-178
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• 2019

Although the needs for providing resilient PNT information are increasing, threats due to the intentional RFI or space weather change are challenging to resolve. eLoran, which is a terrestrial navigation system that use a high-power signal is considered as a best back-up navigation system. Depending on the user's environment in the eLoran system, the user may use one of E-field or H-field antennas. H-field antenna, which has no restriction on setting stable ground and is relatively resistant to noise of general electronic equipment, is composed of two loops, and shows anisotropic gain pattern due to the different measurement at the two loops. Therefore, the H-field antenna's phase estimation value of signal varies depending on its direction even at the static environment. The error due to the direction of the signal should be eliminated if the user want to estimate the own position more precisely. In this paper, a method to compensate the error according to the geometric distribution between the H-field antenna and the transmitting station is proposed. A model was developed to compensate the directional error of H-field antenna based on the signal generated from the eLoran signal simulator. The model is then used to the survey measurement performed in the land area and verify its performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.924-930
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• 2018

The objective of this study was to investigate heating performance characteristics of electric heat pump system in a fuel cell electric vehicle (FCEV). In order to analyze heating performance characteristics of electric heat pump system with plate-type heat exchanger using stack coolant to evaporate the refrigerant, R-134a, each component was installed and tested under various operating conditions, such as air inlet temperature of inner condenser and compressor speed. When the air inlet temperature of inner condenser was varied from $0.0^{\circ}C$ to $-20.0^{\circ}C$, heating capacity was not quite different due to similar temperature gap between inlet and outlet of inner condenser with electric-driven expansion valve (EEV). However, COP increased until certain EEV opening, especially under 45.0%, because of decreasing power consumption. According to the compressor speed variation from 2,000 to 4,000 RPM, heating capacity and COP were found to have opposite trend. In the future works, stack coolant conditions as the heat source for tested heat pump system were analyzed with respect to heating performance, such as heating capacity and COP.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.87-92
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• 2019

In this paper, we have verified a low-voltage EM(elasto-magnetic) sensing technique for tensile force management of PSC(prestressed concrete) internal tendon in order to apply the technique to actual construction sites where stable power supply is difficult. From observation of past domestic and overseas PSC structural accident cases, it was found that PS tension is very important to maintain structural stability. In this paper, we have tried to measure the tensile force from a magnetic hysteresis curve through EM sensors according to voltage value by using relation between magnetostriction and stress of ferromagnetic material based on elastic-magnetic theory. For this purpose, EM sensor of double cylindrical coil type was fabricated and tensile force test equipment for PS tendon using hydraulic tensioning device was constructed. The experiment was conducted to confirm relationship between changes of permeability and tensile force from the measurement results of the maximum / minimum voltage amount. The change of magnetic hysteresis curve with magnitude of tensile force was also measured by reducing amount of voltage step by step. As a result, the slope of estimation equation in accordance with magnitude of magnetic field decreases with the voltage reduction. But it was confirmed a similar pattern of change of magnetic permeability for the magnetic hysteresis loop. So, in this study, it is considered that it is possible to manage the tensions of PSC internal tendon using EM sensing technique in low-voltage state.

• Journal of Korea Water Resources Association
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• v.54 no.5
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• pp.301-309
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• 2021

In this study, we tried to improve the performance of the existing U-net-based deep learning rainfall prediction model, which can weaken the meaning of time series order. For this, ConvLSTM2D U-Net structure model considering temporal consistency of data was applied, and we evaluated accuracy of the ConvLSTM2D U-Net model using a RainNet model and an extrapolation-based advection model. In addition, we tried to improve the uncertainty in the model training process by performing learning not only with a single model but also with 10 ensemble models. The trained neural network rainfall prediction model was optimized to generate 10-minute advance prediction data using four consecutive data of the past 30 minutes from the present. The results of deep learning rainfall prediction models are difficult to identify schematically distinct differences, but with ConvLSTM2D U-Net, the magnitude of the prediction error is the smallest and the location of rainfall is relatively accurate. In particular, the ensemble ConvLSTM2D U-Net showed high CSI, low MAE, and a narrow error range, and predicted rainfall more accurately and stable prediction performance than other models. However, the prediction performance for a specific point was very low compared to the prediction performance for the entire area, and the deep learning rainfall prediction model also had limitations. Through this study, it was confirmed that the ConvLSTM2D U-Net neural network structure to account for the change of time could increase the prediction accuracy, but there is still a limitation of the convolution deep neural network model due to spatial smoothing in the strong rainfall region or detailed rainfall prediction.