• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.4
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• pp.148-153
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• 2003

In this paper, the low voltage 3V Sigma-Delta Digital Analog Converter(DAC) is designed for using in the transmitter of ADSL analog front-end. We have developed the CMOS DAC according to ANSI T1.413-2(DMT) standard specifications of the chip. The designed 4th-order DAC is composed of three block which are 1-bit DAC, 1st-order Switched-Capacitor filter and analog active 2nd-order Resistor-Capacitor(RC) filter. The HSPICE simulation of the designed DAC showing 65db SNR, is connected with 1.1MHz continuous lowpass filter. And also, we have performed the circuits verification and layout verification(ERC, DRC, LVS) followed by fabrication using TSMC 2-poly 5-metal p-substrate CMOS $0.35{\mu}m$ processing parameter. Finally, the chip testing has been performed and presented in the results.

• ETRI Journal
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• v.33 no.2
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• pp.295-298
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• 2011

We propose a motion-compensated frame interpolation method in which an accurate backward/forward motion vector pair (MVP) is estimated based on a parabolic motion model. A reliability measure for an MVP is also proposed to select the most reliable MVP for each interpolated block. The possibility of deformation of bidirectional corresponding blocks is estimated from the selected MVP. Then, each interpolated block is produced by combining corresponding blocks with the weights based on the possibility of deformation. Experimental results show that the proposed method improves PSNR performance by up to 2.8 dB as compared to conventional methods and achieves higher visual quality without annoying blockiness artifacts.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.94-99
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• 2010

In this paper, we discuss a proposed two hop relay network with PB/MC-CDMA(partial block MC-CDMA) technique. The main advantages of PB/MC-CDMA system are the increased cell capacity and the high quality of performances. In the system, we employ relay scheme to focus on the coverage reduction and hotspot problem, hotspot is a location where a cluster of users are blocked or dropped for the reason of insufficient frequency resources. Frequency resource allocation scheme is put forward in a three cells system according to each problem. The simulation result shows the performance of the two hop transmission is better than the direct transmission and the proposed network can support much more users to relief hotspot effect compared to the conventional one.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.155-158
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• 2008

In 1989, Kocher et al. introduced Differential Power Attack on block ciphers. This attack allows to extract secret key used in cryptographic computations even if these are executed inside tamper-resistant devices such as smart card. Since 1989, many papers were published to improve resistance of DPA. At FSE 2003 and 2004, Akkar and Goubin presented several masking methods to protect iterated block ciphers such as DES against Differential Power Attack. The idea is to randomize the first few and last few rounds(3 $\sim$ 4 round) of the cipher with independent random masks at each round and thereby disabling power attacks on subsequent inner rounds. This paper show how to combine truncated differential cryptanalysis applied to the first few rounds of the cipher with power attacks to extract the secret key from intermediate unmasked values.

• Macromolecular Research
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• v.15 no.3
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• pp.225-233
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• 2007

To improve the poor mechanical and low-temperature properties of glycidyl azide polymer (GAP)-based propellants, the addition of binders was investigated using GAP and flexible polymer backbone-structural polycaprolactone (PCP) at various weight(wt) ratios, and varying the ratio of Desmodur N-100 pluriisocyanate (N-100) to isophorone diisocyanate (IPDI). Using Gee's theory, the solubility parameter of the PCP network was determined, in order to elucidate the physical and chemical interaction between GAP and PCP. The structure of the binder networks was characterized by measuring the cross-link densities and molecular weights between cross-links ($M_c$) obtained by a swelling experiment using Flory-Rhener theory. The thermal and mechanical properties of the segmented block copolyurethane (GAP-b-PCP) binders prepared by the incorporation of PCP into the binder recipes were investigated, along with the effect of the different curatives ratios.

• Smart Structures and Systems
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• v.29 no.3
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• pp.421-431
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• 2022

Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the sub-blocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.

• Elastomers and Composites
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• v.25 no.4
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• pp.273-279
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• 1990

The graft polymerization of 2-hydroxyethylmethacrylate(HEMA) and vinyltriethoxysilane(VTES) onto styrene-butadiene-styrene block copolymer(SBS) was carried out in toluene, with radical initiator such as benzoyl peroxide(BPO) and 2, 2'-azo-bis-isobutyronitrile(AIBIN) under nitrogen atmosphere. The degree of grafting was increased with the increases of the reaction temperature and time. And the effeciency of BPO was superior to that of AIBN. The mechanical properties and molecular weight of graft products were measured and the applicability as adhesive of plasticized PVC leather was examined.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.1
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• pp.20-28
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• 2020

Symbiodinium is a dinoflagellate genus that coexists with coral reefs and is known to provide ultraviolet (UV) protection in nature through the synthesis of mycosporin-like amino acids (MAA). In order to develop a natural and ecofriendly sunblock for use in summer resorts, the possibility of using a Symbiodinium microbiome extract or an MAA was investigated. Two sunblocks, one containing 7% Symbiodinium extract and the other containing MAA were prepared to be tested on hairless mice and human skin. In this clinical study, the sun protection factor (SPF) and Protection factor of UV A (PFA) values of the sunblock containing either Symbiodinium extract or MAA were determined. The SPF values of the sunblock containing Symbiodinium extract and MAA were 10.43 and 10.83, respectively, and the PFA values were 3.42 and 3.39, respectively. Based on their PFA values of ≥2, the UV A protection can be graded as PA+ (low) for both the sunblocks. In addition, the UV-blocking extract of Symbiodinium has a low phototoxicity and cytotoxicity, reducing the possibility of a heavy feeling to the skin or a foreign-body sensation caused by residue build-up. The low toxicity feature of the major sunblock component will also prevent side effects, such as allergic reactions. Although Symbiodinium extract or MAA alone do not provide effectiveprotection against UV irradiation, their protection capacity can be complemented by the addition of inorganic UV-protecting compounds.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.686-688
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• 2010

The supply of context information is increasing with the propagation of ubiquitous computing environment. Recently, as context information is being collected through electronic tags and sensors attached to the environment, we need methods to efficiently store and search large volumes of data. This paper describes the application of the RLE (Run Length Encoding) compression method for sensors that continuously collect data in USN/RFID terminals.Time information is marked on the data and one data block is generated and saved. This paper proposes a storage method that allows us to quickly search data of the desired time and place by recording time information in continuous data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1877-1882
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• 2013

Smart Utility Network (SUN) is not only a core technology of intelligent green home networks but also a future technology which can be applicable to various areas instead of ZigBee. SUN should be compliment with IEEE 802.15.4g standard and can provide high link margin and stable communication data-rate for poor communication surrounding. This paper describes how to design the system simulation environment for the SUN RF transceiver, and also reports the required block-level specification for each circuit and various implementation impairments. Finally, the measured performances of the fabricated RF transceiver, which has utilized the system simulation results, completely satisfies the IEEE 802.15.4g SUN PHY standard.