• 대한임베디드공학회논문지
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• 제11권5호
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• pp.299-304
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• 2016

As public interest in air quality and environment problem is increasing, many researches are being carried out the gas measurement system. Especially, Non-dispersive infrared (NDIR) measurements using Beer-Lambert gas sensing principle with very high selectivity and long life time are noted for reliable method. It is possible to detect various gases such as carbon dioxide (CO2), carbon monoxide (CO), and nitrogen dioxide (NO2), but many researches are mostly concentrated on CO2 sensor. The multi-gas measuring instrument is high price and unwieldy, therefore it is not suitable for wide area required numerous instrument. So we study the NDIR multi-gas measurement system for air quality based on wireless sensor network, and experiment the realized measurement system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1713-1715
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• 2007

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. We have advanced the framework of the multiple time scale congestion control and showed its effectiveness at enhancing performance for the rate-based feedback control. Our contribution is threefold. First, we define a modular extension of the TCP-a function called with a simple interface-that applies to various flavours of the TCP-e.g., Tahoe, Reno, Vegas and show that it significantly improves performance. Second, we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• ETRI Journal
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• 제43권2호
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• pp.173-183
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• 2021

As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.

• 전자통신동향분석
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• 제36권4호
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• pp.34-47
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• 2021

To realize remote surgery from hundreds of kilometers away, a new communication environment with ultra-low latency and high-precision features is required. Thus, ultra-high precision networking technology that guarantees the maximum latency and jitter of end-to-end traffic on an Internet-scale wide area network is in development as part of 6G network research. This paper describes the current status of various networking technologies in ITU-T, ETSI, IEEE, and IETF to ensure ultra-low latency and high precision in wired networks.

• 스마트미디어저널
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• 제13권1호
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• pp.45-51
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• 2024

Long Range Wide Area Network (LoRaWAN) is a widely adopted Internet of Things (IoT) protocol due to its high range and lower energy consumption. LoRaWAN utilizes Adaptive Data Rate (ADR) for efficient resource (e.g., spreading factor and transmission power) management. The ADR manages these two resource parameters on the network server side and end device side. This paper focuses on analyzing the ADR and Gaussian ADR performance of LoRaWAN. We have performed NS3 simulation under a static scenario by varying the antenna height. The simulation results showed that antenna height has a significant impact on the packet delivery ratio. Higher antenna height (e.g., 50 m) has shown an improved packet success ratio when compared with lower antenna height (e.g., 10 m) in static and mobility scenarios. Based on the results, it is suggested to use the antenna at higher allevation for successful packet delivery.

• 한국컴퓨터정보학회논문지
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• 제15권5호
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• pp.93-101
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• 2010

효율적인 네트워크 관리를 위해 중앙 집중적인 구조, 분산 관리 구조, 그리고 하이브리드 구조와 같은 다양한 관리 구조들이 연구되었지만, 어느 구조도 모든 환경에서 효율적이지는 못하다. 본 연구에서는 향후 활용이 많을 것으로 기대되는 광범위한 영역에 분포된 많은 수의 저용량 NE(Network Element)들을 유연성 있게 관리하기 위한 MA+SNMP 기반의 계층적 관리 구조를 제안한다. 제안 구조는 중간 관리 노드를 사용한 계층적 분할 관리 구조이며 관리의 유연성과 NMS의 부하 감소를 위하여 중간 관리 노드는 MA 기반의 분산 처리를 수행하고, NE의 소규모 특성을 고려하여 NE는 SNMP 기반으로 동작한다. 분석을 통해 제시된 환경에서 제안 구조가 기존 관리 구조의 취약점을 해결하여 처리 시간이 개선됨을 보인다.

• 한국항행학회논문지
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• 제22권1호
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• pp.37-42
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• 2018

최근 장비에 부착된 센서들이 네트워크를 통해 실시간으로 현장 정보를 전송하고 처리하여 장비를 제어하는 과정을 자동으로 수행하는 IoT 환경에 대한 연구가 다방면으로 진행되고 있다. 이러한 시스템의 핵심은 데이터 송수신을 위한 네트워크가 필수적인데 넓은 전송 거리를 가진 유선 네트워크가 우선 선택이 된다. 하지만 유선 네트워크의 경우 통신을 구성하기위해 소모되는 시간과 비용이 무선 보다 높은 문제가 존재한다. 본 논문에서는 이러한 문제를 해결하기 위해 LPWA와 BLE 통신을 이용한 LPWA 기반 산업현장의 무선 데이터 전송 시스템을 제안한다. 제안하는 시스템은 BLE를 통해 장비로부터 데이터를 수집하고 LPWA를 이용하여 서버로 데이터를 전송하는 시스템이다. 실험결과 LPWA로 전송할 수 있는 최대 길이의 확산인자(Spreading Factor)는 8인 것을 확인하였으며, 최소 길이에 대한 Spreading Factor는 9인 것을 확인할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.227-229
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• 2014

최근 모바일 네트워크 환경에서 데이터의 공유의 효율적 서비스를 위해 Cloud 환경을 이용한 정보 공유 서비스가 이루어지고 있다. 이때 데이터 전송 기술은 광역 통신, 협역 통신, 초근접 통신으로 분류 되고, 초근접 통신인 NFC가 이동이 가능한 휴대 기기에서 주로 사용된다. 본 논문에서는 근거리 통신망 기술인 NFC 기술을 확장한 Zing 기술을 이용하여 효율적으로 대용량 데이터를 공유하는 시스템을 제안한다. 제안 시스템은 Cloud에서 근접 단말기 간의 정보 공유시 발생 될 수 있는 상호운용성 문제점을 해결하였다.

• International Journal of Computer Science & Network Security
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• 제24권6호
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• pp.67-76
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• 2024

The Internet of Things (IoT) has revolutionized communication and device operation, but it has also brought significant security challenges. IoT networks are structured into four levels: devices, networks, applications, and services, each with specific security considerations. Personal Area Networks (PANs), Local Area Networks (LANs), and Wide Area Networks (WANs) are the three types of IoT networks, each with unique security requirements. Communication protocols such as Wi-Fi and Bluetooth, commonly used in IoT networks, are susceptible to vulnerabilities and require additional security measures. Apart from physical security, authentication, encryption, software vulnerabilities, DoS attacks, data privacy, and supply chain security pose significant challenges. Ensuring the security of IoT devices and the data they exchange is crucial. This paper utilizes the Random Forest Algorithm from machine learning to detect anomalous data in IoT devices. The dataset consists of environmental data (temperature and humidity) collected from IoT sensors in Oman. The Random Forest Algorithm is implemented and trained using Python, and the accuracy and results of the model are discussed, demonstrating the effectiveness of Random Forest for detecting IoT device data anomalies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.423-425
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• 2004

This raper deals with a platform for diagnosis monitoring of partial discharge based on Java virtual machine. This platform is designed for estimating diagnostic parameters of partial discharge signal and displaying Web-page on operating status. For Web-service, hardware of platform is based on a Strongarm processor and software base is designed on Linux and java virtual machine.