• Environmental and Resource Economics Review
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• v.16 no.4
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• pp.781-802
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• 2007

This study estimates a demand function for municipal water in Seoul area using a Stone-Geary functional form. The Stone-Geary model offers more precise estimates for price elasticity of water demand since it explicitly separates 'basic demand' which is not influenced by the price from 'economic demand' which depends on the price. Our results show that about 84% of the total water demand is the basic demand. The results suggest that the minimum consumption range m stepwise price system should be lowered from $30m^3$ to $15m^3$ per month.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.5
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• pp.488-495
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• 2012

The real-time indoor location technology using radio waves has been studied in a variety of environments. One of them, a ship which consists of steel structure has high reception rate but causes significant ranging error due to the reflection of radio waves. In order to reduce location measurement errors that occurs in such a environment, this paper, based on CSS of IEEE 802.15.4a, presents compensation algorithm for localization using modified bilateration and pyroelectric sensor in a ship. The proposed system reduces the number of fixed nodes by estimating the appropriate reception distance between mobile node and fixed node through the analysis of CSS characteristic in a narrow passage such as ship corridors. Also, in the corner section which the ranging errors are significantly fluctuated due to the reflection and diffraction of radio waves, we recognize the location by tracking the a moving section using modified bilateration technique and pyroelectric sensor. The experimental results show that the location accuracy and efficiency of the proposed algorithm are improved 86.2 % compared to general method.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.47-48
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• 2008

UML(Unified Modeling Language) is the most frequently used modeling language in the process of analysis, design, implementation and etc. The main reason of using UML is not only to help users to work visually but also to draw better communication among developers. In addition, UML is one of the global standards and supports MDA. In this paper embedded software development method for USN using UML is discussed To show how the development method is used, IEEE 802.15.4 radio module are programmed using UML software tool.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.268-270
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• 2006

본 논문에서는 ZigBee Alliance에서 다루어지고 있는 IEEE 802.15.4틀 기반으로 하는 USN을 위한 라우팅 프로토콜을 연구한다. 현재 ZigBee Specification v1.0의 표준에서는 AODV라우팅 프로토콜과 Hierarchical 라우팅 프로토콜을 사용하고 있다. 하지만 ZigBee Specification v1.0의 표준에서 사용하고 있는 이 두 가지 라우팅 프로토콜은 대규모의 센서네트워크에 적용하였을 때, 많은 단점들이 존재한다. 이러한 단점들은 센서네트워크가 가지고 있는 여러 가지 특성들을 고려하지 않은 일반적인 Adhoc 네트워크에서 사용하는 라우팅 프로토콜을 사용했기 때문이다. 따라서 본 논문에서는 이러한 단점들을 해결 할 수 있는 클러스터 기반의 라우팅 프로토콜을 제안한다.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.67-70
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• 2004

This paper describes and analyzes the performance of MB-OFDM (Multi-Band OFDM) technology that is suggested as one of standards in IEEE 802.15 TG3a for uwb application. Also the performance of newly proposed SFBC MB-OFDM scheme is compared with that of conventional MB-OFDM system in this paper. Simulation results show that SFBC MB-OFDM system outperforms conventional MB-OFDM system about 1.5dB Eb/No at target BER of $10^{-4}$.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1077-1080
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• 2006

IEEE 표준인 802.15.4와 ZigBee는 적어도 기술적으로는 우리의 삶에 언제어디서든지 네트워킹을 할 수 있게 해주는 청사진을 보여준다. 이것은 아주 간단하고, 본질적으로 네트워크에서 그 자체로만으로 작동하는 장치이고, 그리고 다수의 새로운 응용들을 적용할 수 있을 뿐만 아니라, 현재 존재하는 홈 네트워킹상의 다른 응용들에게 가치를 부여 할 수 있을 것이다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.394-395
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• 2008

본 논문에서는 ZigBee (IEEE 802.15.4b Low-Rate Wireless Personal Area Network; LR-WPAN) 915MHz 대역 수신기에 주파수 옵셋에 따른 성능을 알아보고 수신기 Correlator에 Multiple delay differential filter를 적용하여 주파수 옵셋의 영향을 최소화하는 방법을 제시한다. AWGN 환경에서 주파수 옵셋의 영향이 최대와 최소(ZigBee frequency tolerance) ${\pm}80ppm$, $0{\sim}73200Hz$)일 때의 환경에서 시뮬레이션을 통해 제안한 수신기의 성능을 검증한다.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.879-885
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• 2014

This paper designs and implements the 2 plug type standby power control outlet based on IEEE 802.15.4 using Zigbee and IPv6 network in order to reduce the standby power to the user. The standby power control system is consisted of direct power and standby power plug. Also this system can communicate bidirectionally in wireless because built-in wireless communication modules. One gateway is linked with many standby power control outlet in wireless. Each standby power control outlet executes the operation needed in power control independently. Also each standby power control outlet has its own power can be detected in real time independently of the power can be controlled.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.379-382
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• 2007

In ubiquitous sensor networks(USNs), various sensing devices deployed in wireless sensor networks collect meaningful data from physical environments and the data are delivered to neighbor node through radio interfaces for further processing. In this processing, efficiently using of the limited source of low power and low cost is USNs on the point of energy consumption. In this paper, we measure and analyze the power consumption of LR-WPAN.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.114-116
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• 2006

XCP (eXtensive Control Protocol) is an information oriented protocol which delivers information with high reliability according to the predefined rule. XCP network system can be implemented on top of several physical layer such as power line, IEEE 802.15.4 and so on. In this paper. a monitoring software that evaluates the reliability and performance of the XCP network is designed and implemented. This paper presents the structure and method of the packet monitoring in the network through several interfaces such as RS-232, ethernet.