• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제2권1호
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• pp.15-26
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• 2013

IP기반 무선 센서 네트워크(IP-WSN)는 의료, 주택 자동화, 환경 모니터링, 산업용 제어, 차량 텔레매틱스 및 농업 모니터링 등 광범위하게 적용되고 있다. 이러한 적용은 에너지 효율과 함께 센서의 이동성이 중요한 문제로 다루어진다. 에너지 비효율로 인해 네트워크 기반의 이동성관리 프로토콜은 IP-WSN에서 지원될 수 있다. 본 논문에서는 IP-WSN 프로토콜을 지원하는 멀티캐스팅 기반의 빠른 이동성관리 기법(mSFP)을 제안한다. 네트워크 구조와 시그널링 비용, 이동성 비용 등을 고려한 성능분석을 수행하였고[8,20], 분석 결과 PMIPv6와 SPMIPv6에 비하여 mSFP의 시그널링 비용, 전체 시그널링 비용, 이동성 비용이 모두 감소되었다. IP-WSN 노드의 수 측면에서 mSFP의 시그널링 비용은 7%, 전체 시그널링 비용은 3% 더 감소되었다. 홉의 수 측면에서 mSFP의 시그널링 비용은 6.9%, 전체 시그널링 비용은 2.5% 더 감소되었다. IP-WSN 노드의 수 측면에서 이동성 비용은 1.6%, 홉의 수 측면에서 이동성 비용은 1.5% 더 감소되었다.

• Journal of Communications and Networks
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• 제16권6호
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• pp.667-676
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• 2014

Connectivity is a crucial quality of service measure in wireless sensor networks. However, the network is always at risk of being split into several disconnected components owing to the sensor failures caused by various factors. To handle the connectivity problem, this paper introduces an in-advance mechanism to prevent network partitioning in the initial deployment phase. The approach is implemented in a distributed manner, and every node only needs to know local information of its 1-hop neighbors, which makes the approach scalable to large networks. The goal of the proposed mechanism is twofold. First, critical nodes are locally detected by the critical node detection (CND) algorithm based on the concept of maximal simplicial complex, and backups are arranged to tolerate their failures. Second, under a greedy rule, topological holes within the maximal simplicial complex as another potential risk to the network connectivity are patched step by step. Finally, we demonstrate the effectiveness of the proposed algorithm through simulation experiments.

• 한국정보통신학회논문지
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• 제19권2호
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• pp.477-485
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• 2015

최근 무선 센서 네트워크(Wireless sensor network, WSN)의 제한된 수명을 근본적으로 해결하기 위하여 에너지 수집형 노드를 사용한 WSN 연구가 진행되고 있다. 하지만, 이러한 연구를 원활히 지원하기 위한 에너지 수집형 WSN 시뮬레이터는 거의 없는 상태이다. 에너지 수집형 WSN을 위한 시뮬레이터들은 기존의 배터리 기반 WSN 시뮬레이터의 에너지 모델과는 달리, 에너지 수집 모델과 소비 모델이 결합된 새로운 에너지 모델을 필요로 한다. 아울러 새로운 프로토콜 제안 시, 제안된 프로토콜의 성능과 비교할 수 있는 대표적인 에너지 수집형 WSN을 위한 라우팅 및 MAC 프로토콜들이 포함되어 있어야 한다. 본 논문에서는 다양한 환경 에너지 중 가장 널리 사용되는 태양 에너지 기반의 센서 노드 및 네트워크를 지원하는 시뮬레이터를 설계하고 구현하였다. 제안하는 시뮬레이터는 날씨 및 계절 등의 외부환경과 솔라셀 및 에너지 저장 장치 등의 내부 환경 특성을 고려하여 설계된 에너지 수집 모듈이 구현 되어있고, 태양 에너지 기반 무선 센서 네트워크를 위한 대표적인 라우팅 및 MAC 프로토콜 기법들이 구현 되어 있다. 아울러 사용자 친화형 GUI를 제공하여 손쉬운 사용이 가능하다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1324-1331
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• 2008

Recently, landslides have frequently occurred on natural slopes during periods of intense rainfall. With a rapidly increasing population on or near steep terrain in Korea, landslides have become one of the most significant natural hazards. Thus, it is necessary to protect people from landslides and to minimize the damage of houses, roads and other facilities. To accomplish this goal, many landslide prediction methods have been developed in the world. In this study, a simple landslide prediction system that enables people to escape the endangered area is introduced. The system is focused to debris flows which happen frequently during periods of intense rainfall. The system is based on the wireless sensor network (WSN) that is composed of sensor nodes, gateway, and server system. Sensor nodes and gateway are deployed with Microstrain G-Link system. Five wireless sensor nodes and gateway are installed at the man-made slope to detect landslide. It is found that the acceleration data of each sensor node can be obtained via wireless sensor networks. Additionally, thresholds to determine whether the slope will be stable or not are proposed using finite element analysis. It is expected that the landslide prediction system by wireless senor network can provide early warnings when landslides such as debris flow occurs.

• Journal of information and communication convergence engineering
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• 제20권4호
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• pp.259-264
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• 2022

In wireless sensor networks, sensor nodes are often deployed in large numbers in places that are difficult for humans to access. However, the energy of the sensor node is limited. Therefore, one of the most important considerations when designing routing protocols in wireless sensor networks is minimizing the energy consumption of each sensor node. When the energy of a wireless sensor node is exhausted, the node can no longer be used. Various protocols are being designed to minimize energy consumption and maintain long-term network life. Therefore, we proposed KOCED, an optimal cluster K-means algorithm that considers the distances between cluster centers, nodes, and residual energies. I would like to perform a performance evaluation on the KOCED protocol. This is a study for energy efficiency and validation. The purpose of this study is to present performance evaluation factors by comparing the K-means algorithm and the K-medoids algorithm, one of the recently introduced machine learning techniques, with the KOCED protocol.

• 한국IT서비스학회지
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• 제10권2호
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• pp.247-257
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• 2011

In this paper, we propose a multiple-disseminators determining mechanism for Efficient Code Dissemination with low-delay(ECoDi) for wireless sensor networks (WSN). Code dissemination is in the spotlight as an important research issue since sensor nodes are necessary for updating new software remotely or fixing bugs dynamically. In particular, the time factor for code dissemination is the most important factor in order that the normal operation of nodes can be continuously performed as soon as finishing the dissemination. For this factor, ECoDi determines the set of disseminators through regression analysis based on the size of distributed code and the time of past unicasts and broadcasts. Then it transmits the entire code as a unicast to multiple disseminators, and the disseminators broadcast the code to the remaining neighbor nodes. Performance results on a testbed show that ECoDi reduces dissemination time significantly compared to a conventional scheme.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.998-1007
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• 2018

The advent of Wireless Sensor Networks (WSN) has led to their use in numerous applications. Sensors are autonomous in nature and are constrained by limited resources. Designing an autonomous topology with criteria for economic and energy conservation is considered a major goal in WSN. The proposed honey-hive clustering consumes minimum energy and resources with minimal transmission delay compared to the existing approaches. The honey-hive approach consists of two phases. The first phase is an Intra-Cluster Min-Max Discrepancy (ICMMD) analysis, which is based on the local honey-hive data gathering technique and the second phase is Inter-Cluster Frequency Matching (ICFM), which is based on the global optimal data aggregation. The proposed data aggregation mechanism increases the optimal connectivity range of the sensor node to a considerable degree for inter-cluster and intra-cluster coverage with an improved optimal energy conservation.

• 반도체공학회 논문지
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• 제2권1호
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• pp.9-16
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• 2024

본 논문에서는 무선 센서 네트워크를 위한 생체이식형 초저전력 MICS RF 트랜시버 설게에 대해 다룬다. 400 MHz MICS 표준은 WBAN 무선 센서 시스템 구현을 위해, 인체 내 전파적 특성 및 주변 네트워크와의 간접 최소화하며 고려되었다. 본 논문은 MICS 표준에 부합하는 시스템 및 송수신기 설계를 위한 link budget 및 다양한 송수신 아키텍쳐, 초저전력 송수신기 회로기법을 포함한다.

• Journal of Communications and Networks
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• 제13권1호
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• pp.17-25
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• 2011

A convergecast is a popular routing scheme in wireless sensor networks (WSNs) in which every sensor node periodically forwards measured data along configured routing paths to a base station (BS). Prolonging lifetimes in energy-limited WSNs is an important issue because the lifetime of a WSN influences on its quality and price. Low-energy adaptive clustering hierarchy (LEACH) was the first attempt at solving this lifetime problem in convergecast WSNs, and it was followed by other solutions including power efficient gathering in sensor information systems (PEGASIS) and power efficient data gathering and aggregation protocol (PEDAP). Our solution-chain routing with even energy consumption (CREEC)-solves this problem by achieving longer average lifetimes using two strategies: i) Maximizing the fairness of energy distribution at every sensor node and ii) running a feedback mechanism that utilizes a preliminary simulation of energy consumption to save energy for depleted Sensor nodes. Simulation results confirm that CREEC outperforms all previous solutions such as LEACH, PEGASIS, PEDAP, and PEDAP-power aware (PA) with respect to the first node death and the average lifetime. CREEC performs very well at all WSN sizes, BS distances and battery capacities with an increased convergecast delay.

• Journal of Information Processing Systems
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• 제12권2호
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• pp.275-294
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• 2016

A primary task in wireless sensor networks (WSNs) is data collection. The main objective of this task is to collect sensor readings from sensor fields at predetermined sinks using routing protocols without conducting network processing at intermediate nodes, which have been proved as being inefficient in many research studies using a static sink. The major drawback is that sensor nodes near a data sink are prone to dissipate more energy power than those far away due to their role as relay nodes. Recently, novel WSN architectures based on mobile sinks and mobile relay nodes, which are able to move inside the region of a deployed WSN, which has been developed in most research works related to mobile WSN mainly exploit mobility to reduce and balance energy consumption to enhance communication reliability among sensor nodes. Our main purpose in this paper is to propose a solution to the problem of deploying mobile data collectors for alleviating the high traffic load and resulting bottleneck in a sink's vicinity, which are caused by static approaches. For this reason, several WSNs based on mobile elements have been proposed. We studied two key issues in WSN mobility: the impact of the mobile element (sink or relay nodes) and the impact of the mobility model on WSN based on its performance expressed in terms of energy efficiency and reliability. We conducted an extensive set of simulation experiments. The results obtained reveal that the collection approach based on relay nodes and the mobility model based on stochastic perform better.