• 한국전자통신학회논문지
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• 제13권4호
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• pp.851-858
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• 2018

본 논문에서는 스마트 농장의 경제성과 생산성을 제고하기 위한 스마트 농장을 위한 온습도 제어 알고리즘을 제안하였다. 스마트 농장의 기본 조건을 분석하고, 이를 기반으로 무선통신을 기반으로 하는 스마트 농장내의 센서 및 제어대상간 정보교환 시스템을 설계하였으며, 스마트 농장내의 온도, 습도 그리고 토양습도가 식물 성장에 적합하게 설정된 기준 값을 추종하도록 온습도 제어 알고리즘을 개발하였다. 제안된 설계 방법론 및 제어 알고리즘의 유효성을 검증하기 위해서 2.4GHz 무선통신 기반 소규모 스마트 농장의 프로토타입을 제작하였으며, 온습도 실험을 통해서 그들의 유효성을 확인하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제16권4호
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• pp.254-261
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• 2016

The present research paper is devoted to solving an urgent problem, i.e., the energy saving and energy efficiency of buildings. A rapid settlement method and experimental control of the energy conservation based on the specific characteristics of the thermal energy consumption for the heating and ventilation of the buildings, and as well as the rapid development of wireless sensor networks, can be used in a variety of monitoring parameters in our daily lives. Today's world has become quite advanced with smart appliances and devices such as laptops, tablets, TVs, and smartphones with various functions, and their use has increased significantly in our day-to-day lives. In this case, the most important role is played by a wireless sensor network with its development and use in heterogeneous areas and in several different contexts. The fields of home automation, process management, and health management systems make extensive use of wireless sensor networks. In this paper, we explore the main factors of the microclimate in an indoor environment. We control the temperature humidity, and other factors remotely using sensors and Internet-of-Things technologies.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.423-438
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• 2010

Wireless smart sensors enable new approaches to improve structural health monitoring (SHM) practices through the use of distributed data processing. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While much of the technology associated with smart sensors has been available for nearly a decade, there have been limited numbers of fulls-cale implementations due to the lack of critical hardware and software elements. This research develops a flexible wireless smart sensor framework for full-scale, autonomous SHM that integrates the necessary software and hardware while addressing key implementation requirements. The Imote2 smart sensor platform is employed, providing the computation and communication resources that support demanding sensor network applications such as SHM of civil infrastructure. A multi-metric Imote2 sensor board with onboard signal processing specifically designed for SHM applications has been designed and validated. The framework software is based on a service-oriented architecture that is modular, reusable and extensible, thus allowing engineers to more readily realize the potential of smart sensor technology. Flexible network management software combines a sleep/wake cycle for enhanced power efficiency with threshold detection for triggering network wide operations such as synchronized sensing or decentralized modal analysis. The framework developed in this research has been validated on a full-scale a cable-stayed bridge in South Korea.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.689-709
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• 2010

In this paper, a low cost, low power but multifunctional wireless sensor node is presented for the impedance-based SHM using piezoelectric sensors. Firstly, a miniaturized impedance measuring chip device is utilized for low cost and low power structural excitation/sensing. Then, structural damage detection/sensor self-diagnosis algorithms are embedded on the on-board microcontroller. This sensor node uses the power harvested from the solar energy to measure and analyze the impedance data. Simultaneously it monitors temperature on the structure near the piezoelectric sensor and battery power consumption. The wireless sensor node is based on the TinyOS platform for operation, and users can take MATLAB$^{(R)}$ interface for the control of the sensor node through serial communication. In order to validate the performance of this multifunctional wireless impedance sensor node, a series of experimental studies have been carried out for detecting loose bolts and crack damages on lab-scale steel structural members as well as on real steel bridge and building structures. It has been found that the proposed sensor nodes can be effectively used for local wireless health monitoring of structural components and for constructing a low-cost and multifunctional SHM system as "place and forget" wireless sensors.

• Smart Structures and Systems
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• 제16권3호
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• pp.383-399
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• 2015

Today, as railways increase their capacity and speeds, it is more important than ever to be completely aware of the state of vehicles fleet's condition to ensure the highest quality and safety standards, as well as being able to maintain the costs as low as possible. Operation of a modern, dynamic and efficient railway demands a real time, accurate and reliable evaluation of the infrastructure assets, including signal networks and diagnostic systems able to acquire functional parameters. In the conventional system, measurement data are reliably collected using coaxial wires for communication between sensors and the repository. As sensors grow in size, the cost of the monitoring system can grow. Recently, auto-powered wireless sensor has been considered as an alternative tool for economical and accurate realization of structural health monitoring system, being provided by the following essential features: on-board micro-processor, sensing capability, wireless communication, auto-powered battery, and low cost. In this work, an original harvester device is designed to supply wireless sensor system battery using train bogie energy. Piezoelectric materials have in here considered due to their established ability to directly convert applied strain energy into usable electric energy and their relatively simple modelling into an integrated system. The mechanical and electrical properties of the system are studied according to the project specifications. The numerical formulation is implemented with in-house code using commercial software tool and then experimentally validated through a proof of concept setup using an excitation signal by a real application scenario.

• 한국인터넷방송통신학회논문지
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• 제18권6호
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• pp.33-41
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• 2018

스마트 캠퍼스의 플랫폼으로 사물 인터넷에 대한 아이디어가 점점 대중화되고 있다. 인터넷에 연결하기 위해 통신 네트워크, 센서 노드 및 게이트웨이로 구성된 인프라가 필요하며 각 센서 노드는 환경에서 데이터를 수집할 수 있다. 본 논문은 스마트 캠퍼스 모니터링을 적용하기 위해 인터넷에 구성한 무선 센서 네트워크를 설명한다. 무선 센서 네트워크 모니터링은 저전력 구현 및 통합 시스템을 사용하는 완벽한 솔루션이다. 그러나 제한된 컴퓨팅 범위, 제한된 컴퓨팅 성능, 네트워크 프로토콜의 가용성 부족, 프로그래밍 보안 부족 및 기밀성, 무결성 및 가용성 분야의 보안 오류로 인해 수많은 제약이 있다. WSNM 노드를 위한 새로운 보안 기술과 기능이 개발되었다. 보안 네트워크 연구 개발 및 서비스 거부 (DOS) 및 복잡성 공격 방지를 위한 시스템을 제안하였다. 이러한 시스템이 제대로 구현되면 사전 할당을 통한 에너지 효율성 메커니즘과 안전한 루틴 알고리즘을 통해 핵심 관리 모델의 새로운 키를 제공 할 수 있다.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.75-80
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• 2012

In this paper, a new energy harvesting technology using stray electric field of an electric power line is presented. It is found that energy can be harvested and stored in the storage capacitor that is connected to a cylindrical aluminum foil wrapped around a commercial insulated 220 V power line. The average current flowing into 47 ${\mu}F$ storage capacitor is about 4.53 ${\mu}A$ with 60 cm long cylindrical aluminum foil, and it is possible to operate wireless sensor node to transmit RF data every 42 seconds. The harvested average power is about 47 ${\mu}W$ in this case. Since the energy can be harvested without removing insulating sheath, it is believed that the proposed harvesting technology can be applied to power the sensor nodes in wireless ubiquitous sensor network and smart grid system.

• 센서학회지
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• 제21권2호
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• pp.103-108
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• 2012

Radiofrequency(RF) signal is a key medium to the most of the present wireless communication devices including RF identification devices(RFID) and smart sensors. However, the most critical barrier to overcome in RFID application is in the failure rate in detection. The most notable improvement in the detection was from the introduction of EPC Class1 Gen2 protocol, but the fundamental problems in the physical properties of the RF signal drew less attention. In this work, we focused on the physical properties of the RF signal in order to understand the failure rate by noting the existence of the ground planes and noise sources in the real environment. By using the mathematical computation software, Maple, we simulated the distribution of the electromagnetic field from a dipole antenna when ground planes exist. Calculations showed that the dark area can be formed by interference. We also constructed a test system to measure the failure rate in the detection of a RFID transponder. The test system was composed of a fixed RFID reader and an EPC Class1 Gen2 transponder which was attached to a scanner to sweep in the x-y plane. Labview software was used to control the x-y scanner and to acquire data. Tests in the laboratory environment showed that the dark area can be as much as 43 %. One who wants to use RFID and smart sensors should carefully consider the extent of the dark area.

• Smart Structures and Systems
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• 제6권3호
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• pp.225-238
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• 2010

We report on the development of a new technology for the fabrication of Micro-Electro-Mechanical-System (MEMS) strain sensors to realize a novel type of crackmeter for health monitoring of ageing civil infrastructures. The fabrication of micromachined silicon MEMS sensors based on a Silicon On Insulator (SOI) technology, designed according to a Double Ended Tuning Fork (DETF) geometry is presented, using a novel process which includes a gap narrowing procedure suitable to fabricate sensors with low motional resistance. In order to employ these sensors for crack monitoring, techniques suited for bonding the MEMS sensors on a steel surface ensuring good strain transfer from steel to silicon and a packaging technique for the bonded sensors are proposed, conceived for realizing a low-power crackmeter for ageing infrastructure monitoring. Moreover, the design of a possible crackmeter geometry suited for detection of crack contraction and expansion with a resolution of $10{\mu}m$ and very low power consumption requirements (potentially suitable for wireless operation) is presented. In these sensors, the small crackmeter range for the first field use is related to long-term observation on existing cracks in underground tunnel test sections.

• 로봇학회논문지
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• 제2권4호
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• pp.334-340
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• 2007

This paper introduces a prototype smart home environment that is built in the research building to demonstrate the feasibility of a robot-assisted future home environment. Localization, navigation, object recognition and handling are core functionalities that an intelligent service robot should provide. A huge amount of research effort has been made to make the service robot perform these functions with its own sensors, actuators and a knowledge base. With all complicated configuration of sensors, actuators and a database, the robot could only perform the given tasks in a predefined environment or show the limited capabilities in a natural environment. We started a smart home environment for service robots for simple service robots to provide reliable services by communicating with the environment through the wireless sensor networks. In this paper, we introduce various types of smart devices that are developed for assisting the robot in the environment by providing sensor and actuator capabilities. In addition, we present how the devices are integrated to constitute the smart home environment for service robots.