• Journal of Korean Society for Atmospheric Environment
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• v.24 no.5
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• pp.562-573
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• 2008

Concentrations of volatile organic compounds (VOCs) measured from the local industrial sources in Wanju industrial complex during June $2007{\sim}January$ 2008. The samples were collected from the primary sources (6 emission points) in 4 major factories in Wanju industrial complex as well as two general sources in Wanju County to elucidate the abundances of speciated VOCs and their spacial and temporal distributions depending on source bases. Industrial sources are as follows; fabricated metal manufacture, motor vehicle manufacture, rubber and plastic manufacture, and chemical manufacture factories. Two general source samples were collected from gasoline gas station and dry cleaning shop in urban area. In order to understand the near source influence at receptor, samples from the two receptor sites (one is at center of the industrial complex and the other site is at distance residential area downwind from the center) were collected with sample canister, and analyzed by using GC/MSD. The concentrations from different sources were compared and discussed. The mass contributions of the speciated VOCs to total VOCs measured from industrial sources and ambient ai r at two receptors were presented and discussed.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.3
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• pp.315-327
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• 2005

The total of 35 target VOCs (volatile organic compounds), which were included in the TO-14, was selected to develop a VOCs' source profile matrix of the Yeosu Petrochemical Complex and to test its collinearity by singular value decomposition(SVD) technique. The VOCs collected in canisters were sampled from 12 different sources such as 8 direct emission sources (refinery, painting, wastewater treatment plant, incinerator, petrochemical processing, oil storage, fertilizer plant, and iron mill) and 4 general area sources (gasoline vapor emission, graphic art activity, vehicle emission, and asphalt paving activity) in this study area, and then those samples were analyzed by GC/MS. Initially the resulting raw data for each profile were scaled and normalized through several data treatment steps, and then specific VOCs showing major weight fractions were intensively reviewed and compared by introducing many other related studies. Next, all of the source profiles were tested in terms of degree of collinearity by SVD technique. The study finally could provide a proper VOCs' source profile in the study area, which can give opportunities to apply various receptor models properly including chemical mass balance (CMB).

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.3
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• pp.331-343
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• 2004

The results of individual PAH source profiles that can be applied to receptor model are as follows. The sum of 16 PAH concentrations was 391.41 ng/S㎥ in a tunnel. Phenanthrene was the most abundant compound among 16 PAH, and then pyrene, fluoranthene, anthracene, and naphthalene can be seen in elevated contents. 11,056.61 ng/S㎥ of 16 PAH concentrations in BC oil boiler was two times higher than 6,582.57 ng/S㎥) of those in LNG boiler. Naphthalene was the most abundant compound in both facilities. Phenanthrene, anthracene, and acenaphthylene were the second dominant compound group in order from both facilities. BC oil boiler had relatively high concentration of pyrene compared to LNG boiler that had high concentration of fluorene and did not detect pyrene. The sum of 16 PAH concentrations emitted from MSW incinerators after APCD (air pollution control device) was three times higher than those from MSW incinerators before APCD. However, the concentrations of more than 4-ring PAH compounds (e.g., benzo (a)anthracene) before APCD were higher than those after APCD. This fact implies that PAHs generated by combustion process are eliminated in APCD and they are continuously produced in stack or atmosphere by PAHs precursors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.1049-1057
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• 2017

In-vehicle multimedia systems are one of the most important factors in the automotive industry. Especially, multimedia systems are more important in advanced commercial vehicles such as premium express buses. In this paper, we proposed a multimedia streaming system architecture using MEP(MOST Ethernet Packets) for premium express buses based on MOST150. We have designed and implemented the prototype of proposed multimedia streaming system. We have designed a board based on i.MX6 to operate a proposed multimedia streaming system. The software has designed a multimedia system for premium express buses based on Android which is an open source platform. MOST(Media Oriented Systems Transport) is a high-speed multimedia network technology for in-vehicle multimedia system. The MOST network is able to manage up to 64 devices and ring topology is used basically. In addition, the MOST Network meets EMI(Electro-Magnetic Interference)/ EMC(Electro-Magnetic Compatibility) requirements because it uses plastic optical fibers(POF).

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.1
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• pp.28-34
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• 2017

The vehicle stabilizer link is one of the suspension components that reduces the bumping and rolling during vehicle driving. However, this stabilizer link could be a source of the abnormal noises when its free gaps have higher than normal values. Therefore, the current study aims at investigating the quantitative relationships between the abnormal noises and free gaps of the vehicle stabilizer links, as well as the length of time that the vehicle stabilizer links could be used without generating abnormal noises. In this study, the abnormal noises were measured based on the magnitude of the stabilizer link vibration, while the free gaps were quantified through the force-displacement curves of the stabilizer links. Harsh durability tests were also conducted in order to quantify the operating cycles of the stabilizer links before generating the abnormal noises, along with the concomitant measurements of the free gaps. The current results showed that the abnormal noises of the stabilizer links were detected when its free gaps were larger than 0.12 mm. However, the free gaps of the stabilizer links, which are bigger than 0.1 mm, produced the abnormal noises at 1.5 million cycles under harsh durability test conditions. A parametric study in the future that would reflect the different shapes and sizes of the stabilizer links for diverse vehicles could determine more generalized relationships between the abnormal noises and free gaps of the vehicle stabilizer links.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.2
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• pp.1-8
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• 2011

Traffic congestion is a source of significant economic and social costs in urban areas. Intelligent Transportation Systems (ITS) are a promising means to help alleviate congestion by utilizing advanced sensing, computing, and communication technologies. This paper proposes and investigates a basic and advanced ITS framework Advanced Traveler Information System (ATIS) using wireless Vehicle to Roadside (Centralized ATIS model: CA model) and Vehicle to Vehicle (DeCentralized ATIS model: DCA model) communication and assuming an ideal communication environment in the typical $6{\times}6$ urban grid traffic network. Results of this study indicate that an ATIS using wireless communication can save travel time given varying combinations of system characteristics: traffic flow, communication radio range, and penetration ratio. Also, all tested metrics of the CA and DCA models indicate that the system performance of both models is almost identical regardless of varying traffic demand and penetration ratios. Therefore, DCA model can be a reasonable alternative to the fixed infrastructure based ATIS model (CA model).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.8
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• pp.544-549
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• 2015

Since LEDs (light emitting diodes) have many advantages as a light source in vehicle headlamp, such as good reliability, energy and space saving, and flexible headlamp design. On the other hand, the dependence of its performance and life on temperature have great influence on its practical use. In this study, design and fabrication of heat sink for vehicle LED headlamp were performed using thermally-conductive plastics. This study focused on the effective heat sink structure with limited space in the vehicle LED headlamp. We designed two different prototype of heat sink by thermal simulation using SolidWorks program, which had excellent temperature characteristics. The two different prototype of heat sink were fabricated by injection molding with thermally-conductive plastics. The results showed that LED $T_j$ (junction temperature) of sample B (model 1) and sample C (model 1, 2) was below then $165^{\circ}C$ when applying the thermally-conductive plastics in heat sink of vehicle LED headlamp.

• Journal of Climate Change Research
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• v.8 no.3
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• pp.265-273
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• 2017

Recently the Paris Climate Change Accord has been officially put into effect, making global efforts to implement Greenhouse Gas (GHG) reductions, and also International environmental regulations in the automotive sector will be further strengthened. The electric vehicle, which minimizes the particulate matter generated by existing internal combustion engine automobiles, is evaluated as a representative eco-friendly automobile. However, charging the battery of an electric vehicle is not fully environment-friendly if it is fueled by electricity that is being generated by fossil fuels as an energy source. The energy generated by the photovoltaic power generation system, which is an infinite clean energy, can be used to charge an electric vehicle's battery. Currently, shortage of charging facilities, time of charging, and high battery prices are the problem of activating the supply of electric vehicles. This study is to build a conjunction between the EVBSS (Electric Vehicle Battery Supply System) and ESS (Energy Storage System), which can quickly supply the photovoltaic charged battery to the required demand. If the charged battery in the Battery Swapping Station (BSS) is swapped swiftly, it will dramatically shorten the waiting time for charging the battery. As a result, if the battery is rented when it is needed, electric vehicles can be sold without the cost of a battery, which accounts for a large portion of the total cost, then the supply of electric vehicles are expected to expand. Furthermore, it will be an important alternative to maneuver climate change by minimizing GHG emissions from internal combustion engine vehicles.

• Journal of Environmental Science International
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• v.12 no.2
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• pp.217-225
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• 2003

Samples of size-fractionated PM10 (airborne particulate matter with aerodynamic diameter less than $10\mu\textrm{m}$) were collected at an urban site in Jeju city from May to September 2002. The mass concentration and chemical composition of the samples were measured. The data sets were then applied to the CMB receptor model to estimate the source contribution of PM10 in Jeju area. The average PM10 mass concentration was 28.80$\mu\textrm{g}/m^3$ ($24.6~33.49\mu\textrm{g}/m^3$), and the FP (fine particle with aerodynamic diameter less than $2.l\mu\textrm{m}$ fraction in PM10 was approximately 8% higher than the CP (coarse particle with aerodynamic diameter greater than $2.l\mu\textrm{m}$ and less than $10\mu\textrm{m}$ fraction in PM10. The CP composition was obviously different from the FP composition, that is, the most abundant water soluble species was nitrate ion in the FP, but sulfate ion in the CP. Also sulfur was the most dominant element in the FP, however, sodium was that in the CP. From CMB receptor model results, it was found that road dust was the largest contributor to the CP mass concentration (45% of the CP) and ammonium nitrate, domestic boiler, and marine aerosol were major sources to the CP mass. However, the secondary aerosol was the most significant contributor to the FP mass concentration (45% of the FP). In this study, it was suggested that the contributions of soil dust and gasoline vehicle became very low due to collinearity with road dust and diesel vehicle, respectively.