• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.315-318
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• 2005

Lots of researches have been focusing on ubiquitous computing which means wherever, whenever, whatever the required information must be accessible. In ubiquitous computing environment, ubiquitous sensor network (USN) is the basis technology for gathering and transferring the required information. However sensor network characteristically has more severe vulnerability than the existing networks do. The paper presents operation of secure protocols for delivering information in secure in ubiquitous computing environment and show improvement of the secure transferring protocol.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.77-80
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• 2005

Wireless sensor networks(WSN) technology has various applications such as surveillance and information gathering in the uncontrollable area of human. One of major issues in WSN is the research for reducing the energy consumption and reliability of data. A system with forward error correction(FEC) can provide an objective reliability while using less transmission power than a system without FEC. In this paper, we propose to use LDPC codes of various code rate(0.53, 0.81, 0.91) for FEC for WSN. Also, we considered node-to-node interference in addition to AWGN channel. The proposed system has not only high reliable data transmission at low SNR, but also reduced transmission power usage.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.387-392
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• 1994

Recently, as the problems according to lack of skilled labour and superior construction materials were gathering strength, there were required the advent of a special materials in building construction division. As a view of the point, the cement-based Self leveling mortar was developed for improvements of the former problems. The Self leveling mortar has the all kinds of the properties as followed the premixed products in plant, self-smoofhing, non shrinkgae etc, accordingly the finishing of concrete floor don't need skilled labour. The purpose of this study is to establish the introduction of a finishing construction method for concrete floor and slab using the cement-based self leveling mortar. Presented is a study on the basic properties of fresh and hardened self leveling mortar. To this end, an actual floor's finishing construction using the cement-based self leveling mortar was conducted in approximately 1,800㎡ floor as to compare the flatness and levelness after finighing.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.54-59
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• 1991

This experimental investigation was aimed at gathering information on the flexural properties, including ductility, of high-strength lightweight concrete members(concrete with a dry unit weight of approximately 1.85t/$\textrm{m}^3$ and with compressive strength approaching 630kg/$\textrm{cm}^2$ at 56days) under reversed cyclic loading. Two sets of six specimens each were manufactured using lightweght aggregate concrete having compressive strength of 350kg/$\textrm{cm}^2$ at 28days and 630kg/$\textrm{cm}^2$ at 56days. The test variables were the concrete strength, the amount of longitudinal reinforcement, and the spacing of ties. The test results, including hysteretic load-deflection curves, for the specimens representing columns under zero axial load are reported in this paper.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.73-78
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• 2002

This study examines self-compacting of concrete using Ground Calcium Carbonate(GCC) gathering in limestone mine of Banyans district in order to make self-compacting concrete in the range of design strength 300kgf/cm$^2$ and the optimal mix proportion of self-compacting concrete that can use in field structure. The result shows that the optimal GCC replacement ratio is 45$\pm$5% in the normal strength of design strength 300kgf/cm$^2$ and that the volume ratio of the optimal fine aggregate used as the way satisfying both viscosity and compacting ability without separating materials is 46%. The optimal volume ratio of the coarse aggregate considering the economical aspect of concrete is 50%. It is desirable that the optimal mix proportion satisfying self-compacting for replacement of GCC is decided through mix design according to each replacement ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.600-603
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• 2004

Recently, the river sands are in short supply. Gathering sea-sand will be faced with difficulty. Alternative aggregates for concrete are estimated by many researchers. The aggregates are blast furnace slag, steel slag, copper slag, ferro-nickel slag and recycled aggregate and etc. Nevertheless steel slag has been limited in practical use due to its expansibility which is occurred reaction with water and free CaO in slag. Most recently stable management method is to minimize the expansibility researched and developed. First of all, slump, air content, compressive strength and flexural strength are measured in concrete. An estimate is made of the segregation of concrete containing atomized steel slag by Image Analyser program.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1143-1148
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• 2013

This paper deals a watt-hour meter monitor system with applying a Power Line Communication (PLC) modem and a Data Concentrator Unit (DCU). PLC modem uses the power line, so there is no need to install dedicated wiring. This system makes it possible to monitor the amount of electricity of previous current month metering data, so it can easily apply a PC-management for the electric charges and maintenance with gathering the metering data.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.7
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• pp.181-205
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• 1997

It is expected that Korean restaurant business will become one of the most important contributors to the notion's economy by the year 2000. As the many visible and invisible trade barriers are tumbled down and market opening to foreign competition expedites, a strategy to solidify the competitiveness of the restaurant industry is urgently needed. Some of the strateges that need to sharpen the competity edge are as follows: 1. Development of restaurant business management knowhow and enhancement of information gathering capability. 2. Development of its own unique brand of food and service tailored to many different tastes of clientele. 3. Promotion of the industry's globalization efforts with the development of local restaurant brand & Korean traditional foods and with the expansion of foreign investment. 4. Reinforcement of staff training and provision of a compensation package to attract qualified personnel. 5. deregulation of many anachronistic laws and restrictions with government's full support for the industry to realize what it's supposed to be in the 21st century.

• Korean Journal of Human Ecology
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• v.16 no.2
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• pp.237-250
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• 2007

This study was to provide date for developing a effective educational program which would be helpful for teachers to understand children's daily activities more properly. From two kindergartens, 20 children were observed for 3 consecutive hours. The observer followed the target child, gathering data during 30-second "windows". This observation lasted for three hours per day and each child was observed 60 times. The proportion of major activities such as education, play, work, and conversation in children's daily activities was compared. Results showed that children of Waldorf program were more exposed to and engaged in play than children of Theme-based program, whereas children of theme-based program were exposed to and engaged in academic activities than those of Waldorf program.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.208-212
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• 2003

2.4GHz wireless LAN has come into wide use at present according as the use of wireless LAN limited to special fields like network of enterprises or universities has been made gradual popularization and the need for it is gathering strength. Therefore, in this paper, transmission devices and structures of it is investigated and optimum transmission level of signals is researched through experiment about characteristics and rate of transmission of Packet signals in various User environments.