Nae Soo Kim

A Circular Polarized Metallic Patch Antenna for RFID Reader

A novel single feed circularly polarized metallic patch antenna for RFID reader is proposed. The proposed antenna has a simple structure, it has corner truncated square patch, ground plane and a probe feed. In addition to structure of the proposed antenna is simple and low cost. Experimental results of a constructed prototype with the center operating frequency at 911 MHz showed that the antenna has an impedance bandwidth (2:1 VSWR) of about 23 MHz, a 3 dB axial ratio of about 9 MHz, and a gain level of about 9 dBi

Hybrid Sensor Module and Data Processing Using Low-Power Wakeup in WSN

Due to the development and proliferation of ubiquitous technologies and services, various sensor network applications are being appeared on the stage. The needs for algorithms requiring complex signal processing with a high-performance processor such as digital signal processor are also increased. However, it is difficult to use such processor for the low-power sensor network operating with a battery because of power consumption. This paper proposes and implements hardware and software architecture of the hybrid-type sensor module composed of a low-power sensor module and a high-performance sensor module for the complicated signal processing in the wireless sensor node. Although this approach needs some additional hardware, it results in some improvements in operation time supporting complex algorithms for target detection in the sensor networks.

Window Energy Detection for Unmanned Surveillance with PIR Sensor

A PIR sensor is widely applied for motion sensing applications such as automated door control, camera triggering and automated on-off control of lamps. In particular, it is usually used to detect the existence of moving objects in an indoor environment. However, in outdoor, false alarms come about due to environmental changes and other sources. Therefore, it is difficult to provide consistent detecting performance outdoors. This paper presents an algorithm to reduce and minimize the false alarms and provide reliable quality to a surveillance system. We gathered PIR signals outdoors, analyzed collected data and extract target feature defined as the window energy. Using this feature, we made models of target and false alarms and proposed a target decision algorithm. We simulated real PIR signals to provide the performance of the proposed algorithm.

Design and Deployment of Testbed for Experimental Sensor Network Research

This paper presents the Ubiquitous Sensor Network (USN) testbed, which is deployed at Electronics and Telecommunications Research Institute (ETRI), in Republic of Korea. USN testbed is a state-of-the-art sensor network experimental facility composed of various components. It includes heterogeneous sensor nodes with variety of sensing module ranging from ultra-low power to high performance hardware platforms, a scalable and reliable Ethernet based wired backplane network to program, interact with and receive/send data from/to the sensor nodes, an easily extendable application software suite which glues and drive everything in a user friendly manner, and an indoor and outdoor deployment space offering various environmental characteristics. We also included two case studies where researchers have put USN testbed into practice for experimental evaluation of algorithms and networking protocols. The case studies cover routing and clustering protocol in wireless sensor networks.