• Fire Science and Engineering
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• v.31 no.4
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• pp.35-42
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• 2017

Large Eddy Simulation (LES) was peformed for the backdraft occurred in a compartment filled with high-temperature methane fuel using the Fire Dynamics Simulator (FDS) of version 6. The prediction performance of FDS, adopted the Eddy Dissipation Concept (EDC) combustion model with five different chemical reaction mechanisms, was evaluated. The temporal distributions of temperature, fuel mass fraction, velocity and pressure were discussed with numerical results and the pressure variation in time was compared with that of previous experiment. The FDS adopted the EDC model showed the possibility of LES for the backdraft phenomena. However, the prediction performance of the LES with EDC model strongly depended on the chemical reaction mechanism considered. It is necessary that the suitability of the chemical reaction mechanism should be validated in advance for LES with the FDS v6 to be applied to the simulation of backdraft.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.291-297
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• 2018

Due to difficulty in minimally invasive surgery, training simulator is actively researched. A volumetric deformable organ is created by employing a shape-retaining chain-linked (S-chain) model to realize positioning a human organ model in virtual space. Since the main principle of the S-chain algorithm is that the repulsive force is proportional to the number of chain elements, the calculation time can be increased according to the magnitude of deformation. In this work, the advanced S-chain algorithm is used to calculate the repulsive torque according to spin motion. Finally, haptic architecture was constructed using this S-chain model by incorporating the virtual organ with a real master device, which allows the repulsive force and target position to be transferred to each other. The control performance of S-chain algorithm has been evaluated via experiment.

• Atmosphere
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• v.29 no.3
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• pp.283-294
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• 2019

For the upper air observations, a temperature measurement using radiosonde is a common method, and the compensation of solar radiation effects in the radiosonde temperature sensor is an important factor. In this paper, we present various experiments and compensation methods of the radiosonde temperature sensor to overcome the errors caused by the movement of the radiosonde rotation, etc. The methods and procedures of this study are as follows. First, we used the solar simulator to analyze the temperature variation and solar effect of the temperature sensor in the radiosonde according to the insolation. We also analyzed the temperature variation and solar effect of the temperature sensor according to the incident angle between the solar simulator and radiosonde. Second, we measured and analyzed solar radiation absorbed by solar cells attached to radiosonde. Third, we present combined compensate solution of the first and the second experiment results, to overcome errors caused by insolation effects in the radiosonde temperature sensors. Fourth, we compared that the reference temperature in similar environment with the upper air conditions, to verify the new radiated compensation performance of the radiosonde temperature sensor. Finally, the radiosonde fabricated in this study was raised to the atmosphere, and the laser correction algorithm proposed through experiments was reviewed. As a result of the radiosonde SRS-10 produced in this study, the temperature deviation from Vaisala RS92 was $0.057^{\circ}C$ in nighttime observation, $0.17^{\circ}C$ in daytime observation, It is expected that the GRUAN under WMO will be able to obtain a high test rating of 5.0.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.226-230
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• 2003

In this thesis I analyzed that V5.2 protocol function is effective to fulfill all of the services that are provided at the existing local exchange. I analyzed this in five methods that refer to ETSI inside patronage. I experimented turnaround time by Start-up method and verified V5.2 protocol function when Start-up. Also I confirmed stability of system by the reconstruction-ability experiment related E1 switch over. I verified V5.2 protocol function through PSTN call process that uses a special service test and local call simulator. As a result of experiment, I confirmed the best method when simultaneous Start-up. V5.2 protocol function was excellent and It becomes switch over at 1/1000 seconds when E1 is out of service. V5.2 protocol function was effective to fulfill all of the special services that are provided at local exchange and its long call process ability was superior to KT standard with 4 fails in 20000 calls. Through the experiment, it was proved that V5.2 interface will become a significant element of communication network when after LE side expanse of v5 interface ID with TDX-100 exchanger and the AN occurrences OOS by message transmission limit and call disconnect when E1 switch over are improved.

• Atmosphere
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• v.29 no.4
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• pp.355-365
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• 2019

Based on in-situ monitoring data produced by National Institute of Meteorological Sciences, we evaluated the performance of Joint UK Land Environment Simulator (JULES) on the surface energy balance for rice-paddy and cropland in Korea with the operational ancillary data used for Unified Model (UM) Local Data Assimilation and Prediction System (LDAPS) (CTL) and the high-resolution ancillary data from external sources (EXP). For these experiments, we employed the one-year (March 2015~February 2016) observations of eddy-covariance fluxes and soil moisture contents from a double-cropping rice-paddy in BoSeong and a cropland in AnDong. On the rice-paddy site the model performed better in the CTL experiment except for the sensible heat flux, and the latent heat flux was underestimated in both of experiments which can be inferred that the model represents flood-irrigated surface poorly. On the cropland site the model performance of the EXP experiment was worse than that of CTL experiment related to unrealistic surface type fractions. The pattern of the modeled soil moisture was similar to the observation but more variable in time. Our results shed a light on that 1) the improvement of land scheme for the flood-irrigated rice-paddy and 2) the construction of appropriate high-resolution ancillary data should be considered in the future research.

• Journal of Korean Society of Transportation
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• v.29 no.5
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• pp.67-78
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• 2011

This paper analyzes the characteristics of drivers' workload observed from with 30 participant drivers with respect to two physio-physiological parameters. For investigating physio-physiological characteristics of road drivers, bio-signals from brain's occipital lobe between simulation experiment and real driving experiment are collected and analyzed. The major findings from the analysis are summarized as follows: First, the drivers' physio-physiological workload is a good parameter for explaining the workload characteristics of road drivers. Secondly, the two physio-physiological workload parameters selected, i.e., beta value and relative energy parameter, are revealed to be statistically significant. Thirdly, it is also revealed to be statistically significant to select 90 percentile measurements in simulator experiment to explain the road drivers' characteristics. Finally, the maximum workload of road design driver is 31.72 in beta parameter, whereas the minimum workload is 1.296 in relative energy parameter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.665-667
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• 2016

Due to the depletion of fossil fuels and the environmental problems of recent years it has been increasing every year the interest in renewable energy. Renewable energy is clean and the typical method using solar and wind power and solar power as an energy source reusable. Wind power generation system of which it is a method of using the natural wind, convert the kinetic energy of the wind into electrical energy. Traditionally, implementing a wind power system, wind tunnel tests was to configure an environment similar to a real wind tunnel experiments. However, it costs a lot of money problems hagieneun configure these wind tunnel tests. Therefore, by this paper, in consideration of the fact, the characteristics of the generator in the wind tunnel experiment to experiment with such a wind tunnel test using a bad test by configuring the motor and controls the motor generator to obtain a result similar to the wind tunnel experiment.

• Journal of Biomedical Engineering Research
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• v.44 no.2
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• pp.157-165
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• 2023

The purpose of this study was to evaluate the importance of developing slim seats with ergonomic design to improve seat comfort and expand the interior space. Two seats were used for the experiment: a sample seat designed based on hip shape and spinal alignment and a normal seat with a flat design without curves. Subjects sat in both the sample seat and a normal seat applied to the vehicle simulator and the experiment was conducted. The next part of the experiment was conducted in two different postures: a driving posture and a relaxed posture. The subjects filled out a comfort questionnaire immediately after sitting and after 30 minutes. The results showed that the comfort in the sample seat was found to be more comfortable than the normal seat. However, no significant difference was noted for the relaxation posture. Pressure distribution was also recorded immediately after sitting and after 30 minutes. In the case of pressure distribution, it was confirmed that the pressure in the sample seat was more evenly distributed in both the driving and relaxed postures than in the normal seat. The results showed that the ergonomically designed sample seat greatly improved seating comfort and pressure distribution compared to the normal seat, which is a general vehicle seat design.

• Journal of the Ergonomics Society of Korea
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• v.36 no.2
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• pp.87-108
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• 2017

Objective: The purpose of this study was to precede the acceptance study based on automation steps and user experience that was lacked in the past study on the core technology of autonomous vehicle, ADAS. The first objective was to construct the acceptance model of ADAS technology that is the core technology, and draw factors that affect behavioral intention through user experience-based evaluation by applying driving simulator. The second one was to see the change of factors on automation step of autonomous vehicle through the UX/UA score. Background: The number of vehicles with the introduction of ADAS is increasing, and it caused change of interaction between vehicle and driver as automation is being developed on the particular drive factor. For this reason, it is becoming important to study the technology acceptance on how driver can actively accept giving up some parts of automated drive operation and handing over the authority to vehicle. Method: We organized the study model and items through literature investigation and the scenario according to the 4 stages of automation of autonomous vehicle, and preceded acceptance assessment using driving simulator. Total 68 men and woman were participated in this experiment. Results: We drew results of Performance Expectancy (PE), Social Influence (SI), Perceived Safety (PS), Anxiety (AX), Trust (T) and Affective Satisfaction (AS) as the factors that affect Behavioral Intention (BI). Also the drawn factors shows that UX/UA score has a significant difference statistically according to the automation steps of autonomous vehicle, and UX/UA tends to move up until the stage 2 of automation, and at stage 3 it goes down to the lowest level, and it increases a little or stays steady at stage 4. Conclusion and Application: First, we presented the acceptance model of ADAS that is the core technology of autonomous vehicle, and it could be the basis of the future acceptance study of the ADAS technology as it verifies through user experience-based assessment using driving simulator. Second, it could be helpful to the appropriate ADAS development in the future as drawing the change of factors and predicting the acceptance level according to the automation stages of autonomous vehicle through UX/UA score, and it could also grasp and avoid the problem that affect the acceptance level. It is possible to use these study results as tools to test validity of function before ADAS offering company launches the products. Also it will help to prevent the problems that could be caused when applying the autonomous vehicle technology, and to establish technology that is easily acceptable for drivers, so it will improve safety and convenience of drivers.

• Science of Emotion and Sensibility
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• v.11 no.3
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• pp.365-374
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• 2008

Using flight simulator tasks with 48 air force cadets, this research examined the effects of pilots' flight skill and self-esteem on risk-taking behavior in the context of social comparison with their cohorts. Flight skill and self-esteem were assessed for individual cadets and three conditions of social comparison (upward-, downward-, and no-comparison) were devised. Flight simulator situations inappropriate for further approach or landing were designed to assess pilots' risk-taking behavior. Weather conditions in the simulator were inadequate to make a landing and the recommended strategy was to break off the approach and attempt a go-around. In this experiment, pilots' risk taking was measured in terms of their approach altitudes; the lower approach altitudes indicative of the higher risk-taking. Our results showed interaction effects of flight skill, self-esteem, and social comparison on risk-taking behaviors. For pilots who were either high or low in both self-esteem and flight skill, social comparison had no effect on risk-taking behavior. However, pilots with high self-esteem but low flight skill showed more risk-taking behaviors in social comparison conditions. And, pilots with low self-esteem but high flight skill showed risk-aversive behaviors in the downward-comparison condition.