• Journal of Korea Multimedia Society
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• v.15 no.7
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• pp.920-930
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• 2012

In this paper, we designed and built a wired temperature controller system which is based on ASIC for a wireless temperature controller system based on FPGA. FPGA devices and wireless controller systems are growing quickly especially for industrial systems for sensing temperature and humidity. FPGA can set up a desired system and a CPU, and directly set up or change a peripheral device based on an IP quickly for an affordable price. This wireless system is easy to install in the field where there are lots of changes and the system is complex. It also has advantages for maintenance. In this study, we are using a 32 bit RISC CPU based on MicroBlaze, with a touch interface, peripheral device, and porting the embedded Linux. Also, we added wireless communication using ZigBee. With this system we provide remote monitoring and control through the web by adding a web server. Compared to the original system, we say not only a performance improvement, but also more efficient development and cheaper costs. In this study, we focused especially on building a better development environment and a more effective user interface.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.4
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• pp.243-248
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• 2013

In wireless sensor networks, consensus algorithms for dynamic systems may flexibly usable for their data fusion of a sensor network. In this paper, a distributed data fusion filter is implemented using an average consensus based on distributed sensor data, which is composed of some sensor nodes and a sink node to track the mean values of n sensors' data. The consensus filter resolve the problem of data fusion by a distribution Kalman filtering scheme. We showed that the consensus filter has an optimal convergence to decrease of noise propagation and fast tracking ability for input signals. In order to verify for the results of consensus filtering, we showed the output signals of sensor nodes and their filtering results, and then showed the result of the combined signal and the consensus filtering using zeegbee communication.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.365-372
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• 2014

In this paper, We implement a power-saving and efficient measures in buildings using the smart-meter. In order to save electric power energy, We propose an improved automatic power-factor controller(APFC) and demand control measures. This is achieved by controlling directly circuit breakers and the capacitor bank feeders in real time via a two-way smart-meter's ICT skills. Improved APFC is minimizing installation costs by series-parallel connecting heterologous capacitors to form a more diverse capacitor banking and controlling using the smart-meter. In order to suppress the demand power, We have designed a smart-meter with communication functions using Atmel's AVR465 and tested an operated lodging building for 24-hours. As a result, We made sure to always retained more than 95% power factor and did not occur over compensation.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.238-243
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• 2006

휴대용 단말기의 보급과 인터넷 및 무선 네트워크의 발달로 사용자들이 사용하는 개별 장치들이 보편화되어 있으며, 이들을 서로 유기적으로 엮은 서비스가 등장하고 있다. 본 논문에서는 이러한 서비스의 한 종류로 U-Kiosk의 개념을 소개한다. U-Kiosk는 Kiosk 단말장치나 공용 PC를 사용자 개인의 PC처럼 사용할 수 있도록 하여 이들의 리소스를 직접 제어할 수 있는 기능을 제공한다. 이것을 실현하기 위한 방안으로 본 논문에서는 공용 PC에서 개인 PC의 바탕화면 설정을 포함해 모든 자원을 직접 사용할 수 있도록 하는 부분을 구현하고 설명을 하였으며, 인증 과정에서 사용자의 개입을 최소한으로 줄이는 방법에 대해서 소개한다. 이를 위하여 초소형 보안 단말기인 PANDA를 사용하였으며, Zigbee 통신을 사용하여 사용자의 위치정보를 파악하여 자동으로 인증을 하도록 하는 Transient Authentication의 개념을 도입하였다. 두 컴퓨터 간의 원격 접속을 위해서는 VNC를 이용하여 구현하였으며, 사용자가 공용 PC로부터 일정 거리 안에 있을 경우, 자동으로 원격 접속이 이루어지고, 공용 PC로부터 멀어질 경우 자동으로 접속이 종료되도록 구현하였다. 이를 기반으로 제안하는 U-Kiosk의 개념에 맞는 테스트 베드를 구축 하였다. 이는 UFC Project$^{2)}$의 일부로서 차후 완벽한 인증 인프라를 구축하여 보다 안정적이고 사용하기 편리한 U-Kiosk의 구현에 초석이 될 것이다.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.5
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• pp.619-625
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• 2007

As low power, low cost wireless communication technology like Bluetooth, Zigbee, RFID has been put to practical use together with the wellbeing trend, the concern about ubiquitous health care has been greatly increased and u-Health is becoming one of the most important application in the sensor network field. Especially, development of the medical services to be able to cope with a state of emergency for solitary senior citizens and the aged in silver town is very meaningful itself and their needs are also expected to continuously increase with a rapid increase in an aging population. In this paper we demonstrate the feasibility of extracting accurate heart rate variability (HRV) measurements from photoelectric plethysmography(PPG) signals gathered by a ring type pulse oximeter sensor attached to the finger. For this, we made 2 types of ring sensor, that is reflective and pervious type, and developed the remote monitoring system which is able to collect HR data from ring sensor, analyze and cope with a state of emergency.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.56-63
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• 2012

The WBAN technology means a short distance wireless network which provides each device interactive communication by connecting devices inside and outside of body. Standardization on the physical layer, data link layer, network layer and application layer is in progress by IEEE 802.15.6 TG BAN. Wireless body area network is usually configured in energy efficient using sensor and zigbee device due to the power limitation and the characteristics of human body. Wireless sensor network consist of sensor field and sink node. Sensor field are composed a lot of sensor node and sink node collect sensing data. Wireless sensor network has capacity of the self constitution by protocol where placed in large area without fixed position. Mobile sink node distribute energy consumption therefore network life time was increased than fixed sink node. The energy efficient is important matter in wireless body area network because energy resource was limited on sensor node. In this paper we proposed cluster topology algorithm for efficient data transmission in wireless body area network based mobile sink. The proposed algorithm show good performance under the advantage of grid routing protocol and TDMA scheduling that minimized overlap area on cluster and reduced amount of data on cluster header in error prone wireless sensor network based on mobile sink.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1039-1047
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• 2017

This paper presents a test development of a Fly-By-Wireless flight control system for a fixed-wing unmanned aerial vehicle (UAV). Fly-By-Wireless system (FBWLS) refers to a system that uses a wireless network instead of a wired network to connect sensors and actuators with a flight control computer (FCC), reducing considerable amount of wires. FBWLS enables to design a much lighter aircraft along with decreased maintenance time and cost. In this research we developed a Zigbee-based FWBLS UAV in which sensors (GPS and AHRS) are wirelessly connected via a FCC to aileron and elevator servo motors. In order to see the effect of time delay due to wireless signal on the flight stability of the UAV, several flight tests were conducted. From the tests, it was confirmed that the effect is minor by comparing the flight response of the FBWLS with the corresponding Fly-By-Wire system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.327-332
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• 2017

As Internet of Things (IoT) technology advances, there is a growing demand for location-based services (LBSs) to identify users' mobility and identity. The initial LBS system was mainly used to measure position information by measuring the phase of a signal transmitted from a global positioning system (GPS) satellite or by measuring distance to a satellite by tracking the code of a carrier signal. However, the use of GPS satellites is ineffective, because it is difficult to receive satellite signals indoors. Therefore, research on wireless communications systems like ultra-wide band (UWB), radio frequency identification (RFID), and ZigBee are being actively pursued for location recognition technology that can be utilized in an indoor environment. In this paper, we propose an LBS system that includes the 2.45GHz band for chirp spread spectrum (CSS), and the 3.1-10.6GHz band and the 250-750MHz bands for UWB using the IEEE 802.15.4a standard for low power-based location recognition. As a result, we confirmed that the 2.45GHz Industrial, Scientific and Medical (ISM) band RF transceiver and the ranging function can be realized in the hardware and has 0dBm output power.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.105-109
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• 2020

This study was conducted to the improvement of solar light-based artificial light supply system and effect of lettuce cultivation. The artificial light supply system was consisted of units such as light source, power, system measurement and controller. The light source supply was composed of a solar transmitter and an LED lamp. The power supply consisted of an leakage breaker, SMPS, LED controller and relay. The solar transmitter was made of a quartz optical fiber with optimal light transmission. Artificial light used white lamp among LEDs. System measurement and control consisted of touch screen, Zigbee communication module and light quantity sensor. The results of test confirmed that the LED light is automatically activated when the intensity measured by the light intensity sensor is 200 μmolm^-2s^-1 or less. Moreover, the leaf length, root length, chlorophyll content and root fresh weight of optical fiber treatment was hight than LED lamp treatment. Therefore, it can be inferred that the energy-saving solar light collector device can be effective in the indoor lettuce production. However, the use of LED lamp is also recommended to assure the availability of sufficient sunlight in cloudy and rainy days.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.90-94
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• 2007

Location tracking automation of resources in construction industry is one of the most important procedures to improve construction project performance and reduce the period of construction. Recently, location tracking technologies have proven to be effective in tracking construction materials and equipment in real time through the instrumentality of RFID (Radio Frequency Identification). By using wireless communication and inter-working system between RFID and USN, it is possible that construction engineers receive the location information of construction resources without additional efforts that move the RFID reader to read tags periodically. In the inter-working system, RFID reader delivers the acquired materials information to sensor node which is connected by serial interface. Then sensor node transmits the received data to the data aggregation terminal that is a sink node. The data aggregation terminal can transmit collected data to construction manager who is out of construction site using infrastructure such as CDMA(Code Division Multiple Access) network. The combination model of the two system and field test scenarios are presented in this paper.