• Korean Journal of Optics and Photonics
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• v.29 no.1
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• pp.1-6
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• 2018

In this study, ray-tracing software was used to calculate the optical path length of an optical system. Using the optical path length, the optical phase, group delay (GD), group delay dispersion (GDD), and third-order dispersion (TOD) of the optical system were obtained. Pulse compressors using a prism pair or grating pair were designed to compensate the GDD of a real optical system for a femtosecond fiber laser. Also, a pulse stretcher using a grating pair with lenses or mirrors was designed. The results of this study can be used to calculate the dispersion of an optical system and optimize the performance of an ultrashort pulse laser optical system.

• Journal of Industrial Convergence
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• v.17 no.1
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• pp.33-39
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• 2019

The purpose of this study was to present the direction and implications of urban development in relation to climate risk factors and environment for practical implementation of urban development in response to climate change. The research method was carried out through a qualitative data survey and analysis. As a result of the study, the direction of urban development according to the climate risk factors emphasized the importance of preparing conditions for urban development by establishing a damage prevention system for natural disasters and analyzing the risk of natural disasters by conducting analysis of the impact and vulnerability of climate change in urban planning. The direction of urban development on the environmental side suggested the need for the promotion of public transport oriented development (TOD) in the form of urban planning to realize sustainable and practical urban development. Future research directions will need to be supplemented with more quantitative and empirical findings.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.2
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• pp.109-116
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• 2019

Survivability of soldiers has been greatly threatened by the development of thermal observation device(TOD). Therefore, infrared, especially thermal, stealth technology is applied to combat suit to avoid detection from TOD. In this study, prior to the thermal camouflage performance evaluation of combat suit, thermal signature characteristic from clothed the human body was analyzed considering the realistic condition for human surface temperature compared to that from unclothed human body. To get the realistic surface temperature distribution of human, thermoregulation and multi-layer skin structure model is applied to the human model. Based on temperature distribution, surface diffuse radiance in thermal range is calculated and by assuming the background conditions, contrast radiance intensity(CRI) characteristic of human body is analyzed. By wearing clothing, the CRI between background and human body became reduced in low emissive background but in high emissive background, the contrast is much more prominent. Therefore, this issue should be considered in design process of thermal camouflage combat suit.

• Journal of Auto-vehicle Safety Association
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• v.12 no.4
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• pp.39-47
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• 2020

In this study, crash situations of representative bus crash types were elicited by analyzing a total of 1,416 bus repair record which were collected in 2018~2019. K-means clustering was used as a methodology for this study. Bus repair record contain the information of repair term, type of bus operation, responsibility of accident, weather condition, road surface condition, type of accident, other party, type of road and type of location for each data. Also, by checking collision parts of each bus repair record, each record was classified by types of collision regions. From this, 760 record are classified to frontal type, 363 record are classified to middle-frontal type, 374 record are classified to middle-rear type and 331 record are classified to rear type. As mentioned, k-means clustering was performed on each type of collision parts. As a result, this study analyzed the severity of bus crash based on actual bus accident data which are based on bus repair record not the crash data from the TAAS. Also, this study presented crash situation of representative bus crash types. It is expected that this study can be expanded to analyzing hydrogen bus crash and defining indicators of hydrogen bus safety.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.5
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• pp.659-669
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• 2022

Recently, parking problems have repeatedly occurred not only in the residential areas of the old town, but in detached residential areas, neighborhood living facilities, and commercial areas of the planned New Town. This study suggests a strategy to minimize parking problems before constructing a New Town by reviewing these parking problems at the new city district planning stage. Parking problems can be divided into supply-demand and non-supply-based, and the solution strategy is reviewed in terms of supply and operation. The procedure for applying the solution strategy is proposed according to the effectiveness and ease of application.First, this paper suggests the PAZ (Parking Analysis Zone) as the basic analysis unit. Second, the supply-based parking problem in the concerned area based on the land use plan of Hanam Gyosan is reviewed. Last, solutions to a parking problem for each PAZ are presented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.291-310
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• 2023

This study explores the factors which affect user acceptance for Robo Taxi, an electricity-based Autonomous Vehicles based on a Value based Adoption Model. The three main factors of benefit (usefulness and enjoyment), sacrifice (technicality and perceived fee level), and user experience about mobility services such as car sharing, taxi, and autonomous vehicles, were finally selected as independent variables as a influential factors on perceived values and adoption intention of Robo taxi. The study found that usefulness, enjoyment, and perceived fee had a significant effects on adoption intention, and some user experiences had a significant effect on benefit factors. This study has important implications for incorporating the Value-based Adoption Model results into the service design for the activation of Robo taxi, and furthermore, they can provide a theoretical basis for effective use of the research findings.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.81-92
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• 2023

Traffic state classification is crucial for time-of-day (TOD) traffic signal control. This paper proposed a traffic state classification technique applying Deep-Embedded Clustering (DEC) method that uses a high dimensional traffic data observed at all signalized intersections in a traffic signal control sub area (SA). So far, signal timing plan has been determined based on the traffic data observed at the critical intersection in SA. The current method has a limitation that it cannot consider a comprehensive traffic situation in SA. The proposed method alleviates the curse of dimensionality and turns out to overcome the shortcomings of the current signal timing plan.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.4
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• pp.396-407
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• 2015

The literature about intelligence assets allocation focused on mainly single or partial assets such as TOD and GSR. Thus, it is limited in application to the actual environment of operating various assets. In addition, field units have generally vulnerabilities because of depending on qualitative analysis. Therefore, we need a methodology to ensure the validity and reliability of intelligence asset allocation. In this study, detection probability was generated using digital geospatial data in MGIS (Military Geographic Information System) and simulation logic of BCTP (Battle Commander Training Programs) in the R.O.K army. Then, the optimal allocation mathematical model applied concept of simultaneous integrated management, which was developed based on the partial set covering model. Also, the proposed GA (Genetic Algorithm) provided superior results compared to the mathematical model. Consequently, this study will support effectively decision making by the commander by offering the best alternatives for optimal allocation within a reasonable time.

• Journal of Microbiology and Biotechnology
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• v.4 no.1
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• pp.63-67
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• 1994

A microorganism showing degradative activity towards benzene, toluene and ${\rho}-xylene$ (BTX) was isolated from an activated sewage sludge and was tentatively identified as Pseudomonas fluorescence BE103. This strain was found to utilize benzene and toluene as growth substrates, but to degrade ${\rho}-xylene$ in the obligate presence of a growth substrate. The metabolic product resulted from the cometabolism of ${\rho}-xylene$ was identified as 3, 6-dimethylpyrocatechol by LC/MS analysis, and the metabolic pathway was analyzed to be similar to the tod pathway. From the kinetic studies done regarding BTX biodegradation using Pseudomonas fluorescence BE103, it was revealed that the cometabolism of ${\rho}-xylene$ is significantly affected by the ratio of growth substrate concentration to biomass concentration, and that the cometabolism of ${\rho}-xylene$ initiates only when this ratio was about 0.03.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.209-217
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• 2013

This paper presents a control strategy of 4 wheel drive (4WD) vehicles. Proposed control strategy has simple structure and can easily apply to various vehicles with low cost and time. It is consist of feedforward control for traction ability, fedback control for minimizing the wheel speed difference and yaw control for lateral stability. In addition, to integrate the traction and stability control, a blending function is applied. To evaluate the feasibility of the proposed control strategy, actual vehicle experiment is conducted after deciding the tuning parameter through the simulation. The simulation is accomplished by CarSim and Matlab/Simulink and the actual vehicle test is conducted using full size Sports Utility Vehicle (SUV) equipped rear wheel based solenoid type 4WD device.