• Elastomers and Composites
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• v.36 no.2
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• pp.79-85
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• 2001

It goes to be serious with environmental pollution cause waste rubber. That is why there are lot of studies for efficient recycle. The purpose of this study is to improve the physical properties of EPDM powder by using De-link system. We changed on the size of waste rubber powder and De-link contents. we examined the physical, rheological, mechanical properties. And also examined cross-link state at various De-link. Also we carried out morphological studies after making the weather strip's feature by optical microscope.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.236.2-236.2
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• 2012

We present the interim results of simultaneous time monitoring observations of SiO v=1, 2, J =1-0, $^{29}SiO$ v=0, J =1-0, and $H_2O$ $6_{16}-5_{23}$ maser lines toward about 60 relatively strong SiO and/or H2O maser sources using the single dishes of the Korean VLBI Network from 2009 September to 2012 June. These monitoring sources are composed of representative semiregular variables, Miras, water fountain sources, preplantary nebulae and SiO maser sources of star forming regions etc. The variations of intensity ratios between SiO and $H_2O$ masers and velocity structures are investigated according to stellar optical phases and observational epochs. Several individual sources which show an interesting feature will be presented here.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.36.2-36.2
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• 2011

A cancelling magnetic feature (CMF) is believed to be a result of magnetic reconnection in the low atmosphere of the Sun. In this work, we investigate the physical properties of CMFs, focusing on the rates of flux cancellation in CMFs and the dynamics of chromospheric phenomena coupled with CMFs. First, we have determined the specific rates of flux cancellation using the magnetograms taken by the Solar Optical Telescope (SOT) aboard the Hinode satellite. The specific rates determined with the SOT turned out to be systematically higher than those based on the data taken by the Michelson Doppler Imager (MDI) aborad the SOHO. Second, we analyzed transient Ca II brightenings associated with small-scale CMFs using the SOT/Hinode. We found that in most Ca II brightenings related to CMFs, and the Ca II intensity peaks after magnetic flux cancellation proceeds. Moreover, brightenings tend to appear as pairs of bright points of similar size and similar brightness overlying magnetic bipoles. To further study the brightening and dynamics of chromospherie features associated with CMFs, we have analyzed Fast Imaging Solar Spectrograph (FISS) data. From this data the Doppler motion of chromospheric features above a CMF changed from redshift to blueshift. The duration of such dynamics is very short being less than 2 minutes. These results are unexpected one and can not be explained by any pre-existing pictures of CMFs.

• Polymer(Korea)
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• v.24 no.3
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• pp.366-373
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• 2000

In this study, the PPS/ABS blend system was investigated in order to collectively identify the relationship among blend morphology, chemical compatibilization and thermal property. ABS resin was chemically modified by the incorporation of maleic anhydride through reactive extrusion for enhanced compatibilization, and PPS, ABS and the modified ABS were blend by a sing twin screw extruder. The effect of chemical modification of ABS on the morphological, mechanical, and thermal properities of the resulting blend was examined. A strong interaction was observed between PPS and MABS by optical microsopy as well as scanning electron microscopy, exhibiting a well-dispersed morphological feature. The PPS/MABS blend showing a single glass transition temperature was observed in dynamic mechanical analysis, demonstrating a pseudo-homogeneous phase morphology induced by chemical compatibilization. PPS/MABS blend also exhibited an enhanced thermal stability and heat distortion temperature compared with modified PPS/ABS blend.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.176-183
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• 2005

Laser heat treatment technology is used for improving the feature of fatigue resistance and wear resistance in mobile parts. The purpose of this study is to compare the characteristics of laser heat treatment and high frequency heat treatment, which is commonly used in industrial place. For the preemptive experiment, the distribution, depth and size of hardening and its micro-structural features were compared between surface heat treatment case by defocusing and variables of each process for heat treatment by exclusively manufactured heat treatment optical system. As a result, high frequency heat treatment has wide distribution of hardening depth and width about 3 times larger than laser heat treatment, however, its average hardness showed 621.4Hv which is smaller than the average hardness of laser heat treatment with 691Hv.

• Journal of Applied Reliability
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• v.13 no.3
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• pp.207-216
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• 2013

This paper, we classified LED failure mechanisms that occur due to the delamination and analyzed each of the mechanism that gives the LED PKGs the effect. Usually, the LED is composed of several materials which are LED chips, gold wire, phosphor, epoxy resin, adhesive, reflector and lead frame. These different materials are usually delaminated in trouble conditions which are huge temperature difference, hot and humid or mechanical shocked. When the components are delaminated, a luminance will be lost and moisture be absorbed easily, a thermal resistance be increased attendantly. In this paper, we experimented to investigate failure mechanism of the thermal resistance and failure mechanism of the decrease of luminance that occur due to the delamination. A thermal shock test was performed to reproduce this phenomena by subjecting samples to a cold-hot cyclling process between $-30^{\circ}C$(15min) and $110^{\circ}C$(15min). The samples were inspected at 200, 600 and 1,000 cycles. We measured feature of LED using the spatial analyzer, optical microscope, thermal resistance, photometer, scanning electron microscope (SEM). As a result, the progression of the crack and the thermal resistance and decrease in luminance are proportional to number of thermal shock.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1025-1032
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• 2020

In this paper, we propose a method to classify road weather conditions into rain, fog, and sun using a SVM (Support Vector Machine) classifier after extracting weather features from images acquired in real time using an optical sensor installed on a roadside post. A multi-dimensional weather feature vector consisting of factors such as image sharpeness, image entropy, Michelson contrast, MSCN (Mean Subtraction and Contrast Normalization), dark channel prior, image colorfulness, and local binary pattern as global features of weather-related images was extracted from road images, and then a road weather classifier was created by performing machine learning on 700 sun images, 2,000 rain images, and 1,000 fog images. Finally, the classification performance was tested for 140 sun images, 510 rain images, and 240 fog images. Overall classification performance is assessed to be applicable in real road services and can be enhanced further with optimization along with year-round data collection and training.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.117-128
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• 2008

Compared with the existing bar code system, RFID system has lots of advantages such as it identifies automatically massive objects. We might anticipate RFID technology will be a substitution for an optical bar code system in the near future. However, their feature that uses radio waves may cause various security problems. Many kinds of solutions have been researched to overcome these security problems. In this paper, we analyze the previous proposed protocols. And then, we categorize RFID authentication into two types according to the synchronization requirement between a Back-end Database and a Tag. In addition, we introduce the previous proposed approaches to tag search problem in RFID authentication. And we propose an efficient method which provides fast tag search by using membership test algorithm, a Bloom filter.

• Journal of Korea Multimedia Society
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• v.24 no.1
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• pp.21-29
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• 2021

With the recent increase in the number of households raising pets, various engineering studies have been underway for pets. The final purpose of this study is to automatically generate situation-sensitive captions that can express implicit intentions based on the behavior and sound of cats by embedding the already mature behavioral detection technology of pets as basic element technology in the video capturing research. As a pilot project to this end, this paper proposes a high-level capturing system using optical-flow, RGB, and sound information of cat videos. That is, the proposed system uses video datasets collected in an actual breeding environment to extract feature vectors from the video and sound, then through hierarchical LSTM encoder and decoder, to identify the cat's behavior and its implicit intentions, and to perform learning to create context-sensitive captions. The performance of the proposed system was verified experimentally by utilizing video data collected in the environment where actual cats are raised.

• Journal of Korea Multimedia Society
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• v.25 no.8
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• pp.983-990
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• 2022

In this paper, we implemented a hierarchical encryption system using two-step phase-shifting digital holography(PSDH) technology based on XOR and scramble operations. The proposed encryption system is a system that authenticates access through the issuance of an encryption key for access to individual laboratories, department offices, and universities. In the encryption process, we proposed a double encryption method using XOR and scramble operation with digital technology and two-step phase-shifting digital holography with optical technology. In the two-step PSDH process, an new method of determining the reference wave intensity without measuring it by using random common object image gererated from digital encryption process was also proposed. In the decryption process, the process is performed in the reverse order of encryption process. And only when the various key information used in the encryption process is correct, the encrypted information can be decrypted, so that the user can access the desired place. That is, there is a feature that can hierarchically control the space that can be accessed according to the type of key issued in the proposed encryption system. Through the computer simulation, the feasibility of the proposed hierarchical encryption system was confirmed.