• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.701-704
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• 2007

Recently, More and more consumer enjoy the finance service such as settling, account transferring, stocks investment, and so via mobile device. In the mobile environment, data transferring between the devices is formatted as XML. However, the common XML file is exposed to the attack such as hacking and malignity code, to satisfy security of mobile environment is very difficult. The problem is more seriously at the open platform such as WIPI that is developed by our country. So there is enough reason to propose one system to protect the import data. In this paper, we development the system to digital signature and signature the XML document in order to protect data, and the system is observing the recommendation of the XML Signature Syntax and Processing by W3C. When designing and composition the system, we use the digital signature algorithm RSA, DSA, KCDSA, and HMAC, etc. we test the system at the open WIPI platform.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.11
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• pp.801-805
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• 2009

Hardware based dynamic voltage and frequency scaling is a promising technique to reduce power consumption in a globally asynchronous locally synchronous system such as a homogeneous or heterogeneous multi-core system. In this paper, FPGA prototype design of hardware based dynamic frequency scaling is proposed. The proposed techniques are applied to a FIFO based multi-core system for a software defined radio and Network-on-Chip based hardware MPEG2 encoder. Compared with a references system using a single global clock, the first prototype design reduces the power consumption by 78%, but decreases the performance by 5.9%. The second prototype design shows that power consumption decreases by 29.1% while performance decreases by 0.36%.

• Journal of Arbitration Studies
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• v.27 no.2
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• pp.107-119
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• 2017

In the process of online trading, many unexpected conflicts may occur. The consumer wishes to perform transactions with a seller by trusting the seller's listings, but there are times when even major companies such as Kakao edit their original listings. When the seller edits their listing, it is extremely difficult for the consumer to prove and deal with the problem. If they don't deal with them carefully they may be accused of denigration. This study proposes a consumer protection system to resolve this problem. In case a problem occurs, proof that the original listing was edited can be submitted to a judge in court by using this system, thus preventing these types of problems from happening. If this system is installed, both the seller and consumer know that the terms of contract cannot be falsely changed to the advantage of either side, so the source of the problem can be prevented. This study analyzes the reasons behind the conflicts and presents a systematic way of preventing the problem. This method does not present a financial burden, and provides a way for transactions to be held based on trust for the seller and consumer.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.53-61
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• 1999

Newley developed dentin bonding system which contains self-etching primer performed the removing of smear layer and etching procedure at once. So, it make possible more simple and shorter working time, the stronger bonding strength than conventional dentin bonding system. Cavities were prepared in the buccal and lingual surface of 30 extracted primary molars, and randomly assigned into three equal groups of 10 each. All cavities were filled with Z-100 composite resin following manufacturer's specifications after priming of three different dentin bonding system. Specimens stored for 7 days in 37 degree C water, thermocycled for 1000 cycles between 5 degree C and 55 degree C, immersed in 50% silvernitrate solution for 24 hours, and embedded in resin before being sectioned longitudinally. Data were analyzed by t-test and ANOVA. Mac-Bond II and Clearfil Linear-Bond II showed less microleakage at the occlusal and gingival margins compared to Scotchbond Multi Purpose. All dentin bonding systems showed significantly less microleakage at the occlusal margins compared to the gingival margins. But, there were no significantley difference between each group.

• Journal of Power System Engineering
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• v.21 no.3
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• pp.30-36
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• 2017

Carbon fiber shows excellent heat generation value and thermal efficiency comparing with the metallic materials because of its far infrared-rays and radiant heat. So, high performance and economic steam boiler system for the industry can be manufactured by using the carbon fiber heater. The far infrared ray radiation rate was more than 90 % of carbon fiber. Steam boiler system with carbon fiber heater in this study is made up of heating section. In the proof test of steam boiler, the aimed temperature and dwelling time were at $500^{\circ}C$ for 8,000 hours, $600^{\circ}C$-3,000 hours, and $700^{\circ}C$-1,000 hours. The temperature rise rate of steam boiler with carbon fiber heater was about 40% faster than that of the conventional boiler.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.4
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• pp.383-392
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• 2008

In order to clarify the influence of the change of urban surface albedo on mesoscale meteorological factors during the summertime, numerical experiments with various albedo of urban surface were carried out. Numerical model used in this study is PSU/NCAR MM5 V3.6. As a result of the numerical simulation intended of Busan assumed the increase of albedo of roofs, buildings, or roads, the increase of albedo can make decrease radiation effect of surface, so that it caused drops in ambient air temperature from $0.5^{\circ}C$ to $1^{\circ}C$ on the average, and the downtown of Busan formed along the trough presented a substantial drop in ambient air temperature about $1.5^{\circ}C$. Modeling studies suggest the increased surface albedo in urban area can reduce surface and air temperatures near the ground and affect related meteorological parameters such as winds and the depth of the mixed boundary layer.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.1
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• pp.98-106
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• 1998

This paper shows the temperature distribution of double hull compartment and of cofferdam in a large LNG Carrier. In LNG Carrier, due to the lower cargo temperature($-163^{\circ}C$), structures are forced to lose their strength if additional heat is not supplied. So it is very important to estimate the temperature distribution and the heat flux needed to maintain the structure properly. The temperature of each compartment is obtained using 2-dimensional model analysis and compared with 3-dimensional results. And also this paper gives preliminary estimation of pipe length to supply necessary heat flux in bare pipe and finned pipe.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.177-179
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• 2009

It is increased that need of broadband multimedia service to make useful environment for user and to support the operation of railway system. So study of integrated data transmission in a subway and railway is activated. The research deals with pass loss characteristics of 18GHz microwave that is assigned frequency of integrated data transmission in a subway and railway. It is used sample integrated transmission system in subway and railway of KRRI(korea railroad research Institute) at the tunnel and road. Specification of test sample system is blow. It use OFDM modulation, Wireless frequency is 18GHz and 19GHz, Maximum output power is 20dBm, Receive sensitivity is -90dBm. The pass loss exponent and standard variation of road and tunnel is analyzed.

• The KIPS Transactions:PartC
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• v.17C no.2
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• pp.215-222
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• 2010

IEEE 802.15 WPAN(Wireless personal area network) technologies represented by Bluetooth are prevalent these days. However, they have short radio coverage and thus cannot be used to build a SNS for servicing users spread over a wide area. In this paper, we develop a mobile SNS(Social Network System) that does not necessitate any infrastructure support using the Bluetooth technology and the mobility based information dissemination technique. Using so-called mobility assisted data dissemination technique we overcome the short radio range restriction of WPAN technologies. We develop Blue Market, a free online marketplace program, as a proof of concept.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.866-871
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• 2006

Recently according to the fashion of well-being, the case study of under floor heating system type for residential space is increasing. Specially double slab floor system can make several roles as reducing the acoustic noises and also supplying fresh air through the gap. So in present study floor heating performance was examined with various location of the space in the case of floor supply air and ceiling supply air. In both cases return air went out through ceiling opening. As one of the result is that when using the heat pipe type floor heating system the temperature difference between supply and return water was $15.2^{\circ}C$, but in case of commercial type floor heating system the temperature difference was $5.3^{\circ}C$ when the supply water temperature was $50^{\circ}C$.