• Journal of Digital Convergence
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• v.17 no.12
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• pp.219-228
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• 2019

Thanks to the development of information technology and the vitalization of smart services, the Internet of Things (IoT) technology, in which various smart devices are connected to the network, has been continuously developed. In the legacy IoT architecture, data processing has been centralized based on cloud computing, but there are concerns about a single point of failure, end-to-end transmission delay, and security. To solve these problems, it is necessary to apply decentralized blockchain technology to the IoT. However, it is hard for the IoT devices with limited computing power to mine blocks, which consumes a great amount of computing resources. To overcome this difficulty, this paper proposes an IoT architecture based on the edge computing technology that can apply blockchain technology to IoT devices, which lack computing resources. This paper also presents an operaional procedure of blockchain in the edge computing-based IoT architecture.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.323-343
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• 2020

Observation data measured at Ieodo Ocean Research Station (IORS) have been utilized in oceanographic and atmospheric studies since 2003. Sea level data observed at the IORS have not been paid attention as compared with many other variables such as aerosol, radiation, turbulent flux, wind, wave, fog, temperature, and salinity. Total sea level rises at the IORS (5.6 mm yr^-1) from both satellite and tide-gauge observations were higher than those in the northeast Asian marginal seas (5.4 mm yr^-1) and the world (4.6 mm yr^-1) from satellite observation from 2009 to 2018. The rates of thermosteric, halosteric, and steric sea level rises were 2.7-4.8, -0.7-2.6, 2.3-7.4 mm yr^-1 from four different calculating methods using observations. The rising rate of the steric sea level was higher than that of the total sea level in the case with additional data quality control. Calculating the non-steric sea level was not found to yield meaningful results, despite the ability to calculate non-steric sea level by simply subtracting the steric sea level from total sea level. This uncertainty did not arise from the data analysis but from a lack of good data, even though tide, temperature, and salinity data were quality controlled two times by Korea Hydrographic and Oceanography Agency. The status of the IORS data suggests that the maintenance management of observation systems, equipment, and data quality control should be improved to facilitate data use from the IORS.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.2
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• pp.131-157
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• 2016

A smog chamber has been an effective tool to study air quality, particularly secondary organic aerosol (SOA), which is typically formed by atmospheric oxidation of volatile organic compounds (VOCs). In controlled environments, smog chamber studies have validated atmospheric oxidation by identifying, quantifying and monitoring products with state-of-art instruments (e.g., aerosol mass spectrometer, scanning mobility particle sizer) and provided chemical insights of SOA formation by elucidating reaction mechanisms. This paper reviews types of smog chambers and the current state of smog chamber studies that have accomplished to find pathways of SOA formation, focusing on gas-particle partitioning of semivolatile products of VOC oxidation, heterogeneous reactions on aerosol surface, and aqueous chemistry in aerosol waters (e.g., cloud/fog droplets and wet aerosols). For future chamber studies, then, this paper discusses potential formation pathways of fine particles that East Asia countries (e.g., Korea and China) currently suffer from due to massive formation that gives rise to fatal health problems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.257-263
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• 2013

In case of image observation equipments, CCTV for short distance visual field is usually installed and operated mostly as the means of crime-prevention. However, the extensive demand for monitoring problems in case of the increase in intelligent crimes and disasters has led to the necessity of the development of long-distance observation equipments embedded with Night View functions. In case of the Night View equipments, the relevant market is set up to be focused mostly on Thermal Observation Device(hereinafter, TOD), but some shortcomings such as the limitation of image visibility and excessive maintenance cost, etc. have actually caused the necessity of new long distance Night View equipment. Moreover there might follow lots of difficulties in long-distance visualization in the event that irregular reflection is generated by minute particles in the atmosphere such as fog, smog, and dust, etc. These factors are motivate the work presented in this study. Our study is aimed at the realization of Pulsed Laser Illuminator and newly proposed Range-Gated image acquisition technology. And also the implementation of Tracker for continuous trace of the objects of interest from the obtained sequence images.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.3
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• pp.16-25
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• 2013

Now it's a trend to install a series of white fluorescent light and orange high pressure sodium lamps because tunnel lighting should be opaque to the safety of drivers from soot, dust, humidity, and fog. Also fluorescent lighting is replaced to LED due to the fact that it improves amenity and object recognition and LED lighting has gradually been improved its nature. In this paper, we have implemented the circuits of the yellow series of high-pressure sodium lamps and white series of LED lights at one board to improve the transparency and recognition of objects. It is possible for inductive high-pressure sodium lamps and the capacitive LED drivers to circuit without power factor compensation. Two circuit parts share only a small number of parts, so low cost LED drivers compared to conventional ones are possible. Therefore, the implementation of the hybrid lighting with high-pressure sodium lamps and LED lights that can be driven at the same time by one driving circuit is possible. The LED capacitive power factor was 0.91 while individually implemented the sodium lamp power factor was 0.98. It shows not only the 2% improvement of hybrid forms but also the efficiency and THD.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.102-105
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• 2002

ADSS(All Dielectirc Self-Supporting) cable installed under high voltage power cable line suffers a variety of environmental influence, rain, wind, snow fall, chemical pollution, salt fog and electrical stress. Its lifetime is required to be at least 20 years with this harsh weathering condition. The electrical stress under high voltage power line gives rise to dry band arcing and tracking, the severest damage, on the outer sheath of cable. Finally tracking might penetrate sheath and cause the break-down of ADSS cable. Tracking resistant sheath material, therefore, should be used to protect the core of ADSS from dry band arcing and to be sure long lifetime. In this work, we discuss various commercial tracking resistant material to investigate the way of track resistance and compare their mechanical, electrical, weathering and tracking properties through serial experiments. We found track resistant material is categorized into two main type : polyethylene with metal hydroxide and polyethylene with reduced carbon black. The Liquid contaminant, Inclined plane Tracking and Erosion test says the time to track of tracking resistant material with metal hydroxide has a little longer time to track in the high applied voltage than that with carbon black, but mechanical and weathering properties were inferior to.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.9 no.1
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• pp.33-54
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• 2003

The aim of this study was to develop a model that could be used in the design of modified atmosphere packaging (MAP) for peaches. Respiratory data at 5, 10, $20^{\circ}C$ for peaches were gathered and altered for create useful respiration model. Packaging materials were conventional low density polyethylene and polypropylene with anti-fog, and anti-fungi treatments, and thickness was $30{\mu}m$ and $50{\mu}m$ each. Permeability tests were performed to find their oxygen, carbon dioxide, water vapor transmission rate as increases in temperature. Test results were then converted to logarithm format for MAP modeling. The maximum rate of oxygen uptake increased with increasing temperature. Optimum gas composition in the package system for fruits were set according to literature and upper or lower limits of oxygen and dioxide established. To predict gas composition at certain storage time, weight of fruits, film thickness, film type, and other variables, respiration rate was studied at various storage conditions. The results of tests were used to calculate Cameron's model and converted to a cubic estimation equation. The validity of the model was tested experimentally by observing actual atmospheric changes inside packages. This result of study may be useful for designing dynamic gas exchange MAP systems for similar agricultural products.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.567-571
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• 2012

The discoloration of traditional paintings could be induced by various chemical reactions of inorganic pigments due to temperature, humidity, light and air pollution. In this study, we made artificial samples including azurite and malachite as inorganic pigments using the traditional method on hanji called 'Korean paper'and investigated the artificial aging process occurred by the interaction between pigments and environmental factors. It was found that the azurite was influenced by the humidity of weathering tests and the salt fog of salt spray tests according to XRD and TGA results. However, it was shown that the malachite was chemically changed by the ultraviolet radiation of weathering tests and UV radiation tests according to color difference and TGA results.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.2
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• pp.103-111
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• 2019

The IoT-driven large-scaled systems consist of connected things with on-chip executable embedded software. These light-weighted embedded things have limited hardware space, especially small size of on-chip flash memory. In addition, on-chip embedded software in flash memory is not easy to update in runtime to equip with latest services in IoT-driven applications. It is becoming important to develop light-weighted IoT devices with various software in the limited on-chip flash memory. The remote instruction execution in cloud via IoT connectivity enables to provide high performance software execution with unlimited software instruction in cloud and low-power streaming of instruction execution in IoT edge devices. In this paper, we propose a Cloud-IoT asymmetric structure for providing high performance instruction execution in cloud, still low power code executable thing in light-weighted IoT edge environment using remote instruction execution. We propose a simulated approach to determine efficient partitioning of software runtime in cloud and IoT edge. We evaluated the instruction cloudification using remote instruction by determining the execution time by the proposed structure. The cloud-connected instruction set simulator is newly introduced to emulate the behavior of the processor. Experimental results of the cloud-IoT connected software execution using remote instruction showed the feasibility of cloudification of on-chip code flash memory. The simulation environment for cloud-connected code execution successfully emulates architectural operations of on-chip flash memory in cloud so that the various software services in IoT can be accelerated and performed in low-power by cloudification of remote instruction execution. The execution time of the program is reduced by 50% and the memory space is reduced by 24% when the cloud-connected code execution is used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.12
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• pp.1571-1576
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• 2018

Recently, the attractive changes of mobile device are a improvement of the computing performance, dramatic improvement of storage capacity, constant connection to the internet, and sophisticated development of display technology. As a result, database applications utilizing mobile devices are emerging. These applications include databases for mobile servers, databases for edge computing, and fog computing. Therefore, it is important to pay attention to the current mobile database and pay attention to whether it has suitable performance for the applications. In this paper, the most common mobile database, SQLite3 is selected and experimented to test and understand the update performance and characteristics. The results of experiment are compared with the one of Oracle database at the same condition to evaluate the experiment. As a result, Insert Performance of SQLite3 has a lot of points to be improved and Update performance is very good. Especially, the performance of Range Query is excellent.