• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.6
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• pp.11-17
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• 2008

This paper proposes the USN node location recognition method with low power, which is the modified centroid method. The conventional Zigbee node location recognition is used to the three RSSI values from three beacons, respectively. When a person move with node, the moving speed of USN node doesn't fast. Therefore, one among three positions used to the value that it is a previous value. This method doesn't large the error in terms of the exact position. Using hand-off method, we get about 30% power advantage than the conventional centroid method. And Our monitoring system add the function that it is possible to search for the node region by color.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.439-441
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• 2007

The seoul metropolitan subway has installed 8 lines and about 500 stations to transport 5 million passengers everyday. The underground air pollution level in the subway stations is very severe status, which is very harmful to the commutators and its personals. Although subway roles as such a massive and huge transportation system, the subway doesn't adapt yet any real-time air monitoring system. They have only some hand-held type detector equipments for monitoring air pollution. Therefore subway passengers are exposed to the harmful air pollution environment. The most harmful environmental parameters among the air pollution are known as the dust and sound noise dB level in the subway station. Because the dust is consisted of very small particles, we can't see them easily in dark condition on the platform, but it is very harmful. The monitoring system for air pollution is developed using embedded system attached with 6 different environmental sensors. This system monitors air pollution of dust sound noise, gas, temperature, humidity, inflammable gas, toxic gas in the subway ?station. The sensor unit of the ARM-CPU board and sensor transmits real time environmental data to the main server using Zigbee wireless communication module and TCP/IP network. The main control server receives and displays the real-time environmental data, and it send alarms to the personals when high level value.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.439-440
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• 2013

As shopping malls and department stores become larger and larger, the parking lots for customers of the facilities provide broad spaces for massive cars. Though managers of the facilities support parking situation plates or numbers of guides in order to help customers, it requires additional costs for managing parking plates or guides. In this paper, we propose the parking system using smart devices. The proposed system exploits sensors and zigbee modules to collect the data of each parking space and shows the current state of the parking lot to customers with smart devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.781-782
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• 2015

To use IoT Technology, it needs a platform to connect each devices. With this reason, Many corporations and organizations are trying to develop their own Platform. Among many platforms we select AllJoyn, IoT open source platform developed by Allseen Alliance which is association led by Qualcomm. Using AllJoyn, we transform data gathered from many communication techniques like WiFi, Zigbee and Bluetooth into AllJoyn platform format and deliver it to other AllJoyn devices. Ultimately, we realize gateway system which enables non-AllJoyn devices to communicate with AllJoyn devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.109-112
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• 2010

Recently, communication components prefer Bluetooth or Zigbee for PAN. However, using these makes expensive and complicated products such as audio equipments, mobile phones, PC, etc. for transmitting simple messages with low rate. In this paper, we propose wireless communication method using ultrasonic in the audio frequency limit band with speakers and microphones which are in products. We suggest transmitting and receiving methods in the audio frequency limit band for transmitting data without affecting audio signal, and implement an ultrasonic communication modem. Finally, we verify the performance of the ultrasonic communication modem by experiments in an environment with background noise.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.58-63
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• 2011

This paper presents a development of a fire control system with an intelligent judgment algorithm of hit or not. The presented algorithm analyzes an impact energy and impact signals according to impact materials. And the detected signals are used to judge the correct hit or not. Furthermore, Zigbee wireless communication technology is applied in the developed fire control system. The wireless communication technology can supply a simple installation of the practical system and free from ageing of communication wire. The presented system is verified in the practical fire test, and the results show the effectiveness of the development system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.734-741
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• 2008

The modern people effort to lead good life. Specially, the patients which prevention of a disease only is cure from this diabetes patient, the old and weak, the hospitals needing a treatment through exercises, and receive medical treatment in houses cure exercise according to exercise prescription. These papers developed a Ubiquitous Care Management system based on Zigbee. This is a system supporting so as accumulation manages the exercise history information that occurred when get exercises prescription, and exercise systematically, and to do preventive of a disease. Can confirm own exercise history and health information through web pages, and this system notifies contents about an exercise treatment to patients as use a cellular phone.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1113-1119
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• 2008

In IP-USN for replacing the sensor network based on Zigbee by IP-based it, routing and the address assignment technique for sensor node are important focuses. But, there is a weak point in existing hierarchical routings. It is that all paths must be searched because the end node isn't considered. And the end node based muting is not sufficient in the mobile sensor network environment because it supports the only simple-path-search. Hereupon, this thesis suggests ComHRP(Complement HRP) that have the only merits of existing methods. The address assignment technique and search method are also proposed. ComHRP simplifies the organization of sensor networks and reduces network complexity. Also, It can efficiently deal with restructuring networks for the unpredictable ubiquitous sensor network feature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.589-591
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• 2009

본 논문에서 제안하고 있는 RT-WISN(Real Time-Wireless Image Sensor Network)는 과거의 무선이미지 전송 기술에 비해 적은 전력을 소모하고 빠른 전송이 가능하게 하는 기술이다. 제안된 RT-WISN은 IEEE802.15.4 표준을 따르고 있으며, 현재 본 연구실에서 개발하고 있는 UoC(Ubiquitous on Chip) 메모리 구조를 응용하여 사용하고 있다. 본 논문에서 제안하고 있는 RT-WISN은 전송하고자 하는 대상이 되는 영상정보의 움직임 변화를 영상 전송 임계값 값을 사용하여 데이터 전송 시기를 결정함으로써 기존의 시스템에 비해 노드의 에너지를 보다 효율적으로 관리할 수 있는 기법 이다. 또한 본 논문에서는 제안된 전용 프로세서를 사용하여 보다 넓은 대역폭에서 필요한 영상 데이터를 효율적으로 전송할 수 있어 전송 시간 제어에 보다 용이함을 제공 한다. 무선센서 네트워크에서 이런 점들은 각 노드들의 생존 시간을 향상하게 되고, 고속의 전송이 가능하게 하는 장점으로 작용하게 된다. 본 논문에서는 Peer-to-Peer 상에서 실제 설계된 메모리 구조를 사용하여 이미지를 무선으로 전송하고 그 전송 시간과 도달률을 측정하여 RT-WISN이 무선 센서 네트워크에서의 검출된 영상 정보의 전송에 적합함을 보인다.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.6
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• pp.299-305
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• 2021

Dissolved oxygen, pH, and temperature are the most important factors for fish farming because they affect fish growth and mass mortality of the fish. Therefore, fish farm workers must always check all pools on the farm, but this is very difficult in reality. That's why we developed a control system for smart fish farms. This system includes a gateway, sensor gatherers, and a PC program using LabVIEW. One sensor gatherer can cover up to four pools. The sensor gatherers are connected to the gateway in the form of a bus. For the gateway, the ATmega2560 is used as the main processor for communication and the STM32F429 is used as a sub-processor for displaying LCD. For the sensor gatherer, ATmega2560 is used as the main processor for communication. MQTT (Message Queuing Telemetry Transport), RS-485, and Zigbee are used as the communication protocols in the control system. The users can control the temperature and the dissolved oxygen using the PC program. The commands are transferred from the PC program to the gateway through the MQTT protocol. When the gateway gets the commands, it transfers the commands to the appropriate sensor gatherer through RS-485 and Zigbee.