• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.469-472
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• 2008

Hierarchical routing in Wireless Sensor Network lowers the amount of a memory used and energy consumption so that the network lifetime longer. But, When Node Failure is occurred, Hierarchical routing do not look for another route. This is the problem of Hierarchical routing. To solve the problem, we would study other hierarchical routings. There are typically hierarchical routing protocols which can be used in WSN, such as the hierarchical routing of Zigbee and HiLow protocol which is submitted as draft to IETF 6LoWPAN WG. Also, there is SCRO algorithm which be able to assign short-cut routing path. This paper explains how to solve the Node Failure in each Zigbee hierarchical routing and HiLow protocol. And we suggest how to solve the Node Failure in SCRO protocol. SCRO protocol is able to assign new routing path rapidly when Node Failure is occurred. Because the strong of SCRO protocol is to assign Short-cut routing path.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.1
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• pp.121-128
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• 2018

Internet of Things architecture connected to the Internet is a technology. However, Many paper research for the lightweight Protocol of IoT Environment. In these Paper excluded secure problem about protocol. So Light weight Protocol has weakness of secure in IoT environment. All of IoT devices need encryption algorithm and authentication message code for certain level of security. However, IoT environment is difficult to using existing security technology. For this reason, Studies for Lightweight IPsec is essential in IoT environment. For Study of Lightweight IPsec, We analyze existing protocols such as IPsec, 6LoWPAN for IEEE 802.15.4 layer and Lightweight IPsec based 6LoWPAN. The result is to be obtained for the lightweight IPsec protocols for IoT environment. This protocol can compatible with Internet network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.173-178
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• 2019

Recently, the types and amount of data generated, collected, and measured in IoT such as smart home, security, and factory are increasing. The technologies for IoT service include sensor devices to measure desired data, embedded software to control the devices such as signal processing, wireless network protocol to transmit and receive the measured data, and big data and AI-based analysis. In this paper, we focused on developing a gateway for interfacing heterogeneous sensor network protocols that are used in various IoT devices and propose a heterogeneous network interface IoT gateway. We utilized a OpenWrt-based wireless routers and used 6LoWAN stack for IP-based communication via BLE and IEEE 802.15.4 adapters. We developed a software to convert Z-Wave and LoRa packets into IP packet using our Python-based middleware. We expect the IoT gateway to be used as an effective device for collecting IoT big data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.1
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• pp.29-36
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• 2009

In this paper, the design and implementation of LNA and down-mixer using 90 nm CMOS process are presented for 60 GHz band WPAN receiver. In order to extract characteristics of the transistor used to design each elements under the optimum bias conditions, the S-parameter of the manufactured cascode topology was measured and the effect of the RF pad was removed. Measured results of 3-stages cascode type LNA the gain of 25 dB and noise figure of 7 dB. Balanced type down-mixer with a balun at LO input port shows the conversion gain of 12.5 dB within IF frequency($8.5{\sim}11.5\;GHz$) and input PldB of -7 dBm. The size and power consumption of LNA and down-mixer are $0.8{\times}0.6\;mm^2$, 43 mW and $0.85{\times}0.85\;mm^2$, 1.2 mW, respectively.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.402-404
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• 2010

IP-USN은 인터넷 프로토콜-유비쿼터스 센서 네트워크(Internet Protocol-Ubiquitous Sensor Network)의 약어로 기존의 IP 인프라를 기반으로 USN에 광범위한 확장성을 제공하고 센서 노드, 게이트웨이 및 싱크 노드의 이동성을 보장하는 USN서비스이다. IP-USN 기술로 현재 IPv6를 바탕으로 6LoWPAN 이라는 표준화 기술이 나왔지만 현재 TCP/IP 망에서는 대부분 IPv4를 사용하기 때문에 바로 운용하기에는 어려운 실정이며 IPv6 는 USN 환경에서 사용하기에는 많은 노드 자원을 사용한다. 따라서 본 논문에서는 현재 TCP/IP 의 IPv4의 망에서 사용가능하며 USN 자체 프로토콜을 사용하는 IP-USN망을 구축하여 End-to-End 통신을 구현하는 방법을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2333-2353
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• 2020

This paper proposes a novel data prioritization and transmission mechanism to minimize the number of packets transmitted and reduce network overload using the constrained application protocol (CoAP) in resource-constrained networks. The proposed scheme adopts four classification parameters to classify and prioritize data from a sensor. With the packet prioritization scheme, the sensed data having the lowest priority is only delivered using the proposed keep-alive message notification to decrease the number of packets transmitted. The performance evaluation demonstrates that the proposed scheme shows the improvement of resource utilization in energy consumption, and bandwidth usage compared with the existing CoAP methods. Furthermore, the proposed scheme supports quality-of-service (QoS) per packet by differentiating transmission delays regarding priorities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3079-3089
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• 2015

In this paper, a smart constrained application protocol (CoAP)-based gateway with a border router is proposed for home safety services to remotely monitor the trespass, fire, and indoor air quality. The smart CoAP gateway controls a home safety sensor node with a pyroelectric infrared motion sensor, a fire sensor, a humidity and temperature sensor, and a non-dispersive infrared CO2 sensor and gathers sensing data from them. In addition, it can convert physical sensing data into understandable information and perform packet conversion as a border router for seamless connection between a low-power wireless personal area network (6LoWPAN) and the Internet (IPv6). Implementation and laboratory test results verify the feasibility of the smart CoAP gateway which especially can provide about 97.20% data throughput.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.46-63
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• 2012

The concept of an "intelligent building" received significant attention from academic, industry and standard development organizations when technically termed a building management system (BMS). Wireless sensor networks (WSNs) and their recent development enhanced monitoring and control applications for the building's areas. This paper surveys and analyzes advantages of the main current and emerging approaches that may be fit for BMS. Specifically, we discuss challenges including interoperability, integration, overhead, and bandwidth limitation of WSNs in BMS. Based on analyses, we highlight the advantages of an IP-based and RESTful architecture approach as the most suitable solution for BMS using WSNs (BMS-WSN). The paper also describes our future direction and design for BMS-WSN based on these advantages. The purpose is to enable interaction of users with BMS-WSN in the same way as with any website while ensuring energy efficiency. A test-bed implementation and evaluation of a BMS application is also introduced in this paper to demonstrate the feasibility and benefits of IP-based and RESTful architecture for BMS.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.11-14
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• 2009

유비쿼터스도시서비스에서의 가장 핵심적인 기술을 유비쿼터스도시서비스를 제공하기 위하여 설치된 도시기반시설물과 도시기반시설물로터 정보를 수집하고, 시설물을 관리하기 위하여 설치된 센서이다. 시설물에 설치된 센서는 USN으로 연결되어서 도시통합운영센서와 통신을 하여 센서로부터 수집된 정보를 전송한다. 도시통합운영센터에서는 USN을 통해서 센서 또는 시설물을 제어한다. 이러한 USN에는 Zigbee, 6LoWPAN등 센서의 특징에 따른 프로토콜이 있고, 유선네트워크, 무선네트워크 등을 통해서 USN의 네트워크를 구성한다. 본 논문에서는 유비쿼터스도시의 시설물 관리를 위해서 사용되어지는 센서 및 USN의 특성을 분석하고, 센서 및 USN의 다양성에서 발생하는 문제점을 분석하고 이를 해결하기 위한 방안을 제시하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.526-529
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• 2007

무선센서네트워크 환경에서 활용될 수 잇는 대표적인 계층적 라우팅 프로토콜로는 Zigbee(지그비) 계층구조 라우팅과 IETF의 6LoWPAN WG에 드래프트로 제출되었던 HiLow 프로토콜 등이 있다. 이들 계층구조 라우팅 프로토콜은 깊이 우선(Depth-first) 방식과 폭 우선(Width-first) 방식을 각각 사용하여 자동 주소 할당을 수행한 후 이를 이용해 계층적 경로 배정이 되도록 한다. 이에 따라 망상의 노드들이 물리적으로 가까운 위치에 존재하더라도 경로는 계층적으로 제공되어 데이터 전달에 많은 흡 수가 소요된다. 본 논문에서는 이러한 경로 배정 시 발생되는 비효율성을 개선하고 싱크(Sink) 주위 노드의 에너지 소모율을 줄일 수 있는 경로 배정 알고리즘을 제안한다.