• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.984-990
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• 2010

Zigbee sensor network technology to build a ubiquitous environment has an important role. However, Zigbee technology, sensing environmental information within the local area to deliver the information because it was designed for the purpose of simple tasks, Attack by a variety of technologies that could potentially compromise the network is very high. To solve this problems, many defense mechanisms are presented in a lot of papers. But, to attack the existing Zigbee various response measures for the implementation of the functionality of the sensor nodes very heavy and high expensive problem. To resolve this problems, with superior computing power Zigbee network coordinator to install, based coordinator to intrusion detection systems is proposed. Coordinator-based IDS(Intrusion Detection System) of the Zigbee network is detected attack, and present a new approach to resolve, possible applications in various fields, so in real life Zigbee technology is expected to contribute to graft.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2307-2314
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• 2008

The study that automates the variety of equipment using the USN(Ubiquitous Sensor Networks) has been executed, and the research field is ranged to almost all fields including a road, harbors. building, military affairs, agriculture and home. By deploying these sensors into the greenhouse environment, we can monitor the environmental change and the growth of plants 24 hours a day. However, the limited resources of a sensor node like limited energy, short transmission range etc, make it difficult to expand the size of the sensor networks. In this paper, we studied to expand the site of sensor networks by using WMN(Wireless Mesh Networks) with simulation. With this simulation, we could validate that using the Wireless Mesh Networks technology for expanding sensor networks is more efficient in the energy aspect than the normal sensor network.

• The Journal of Korean Association of Computer Education
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• v.13 no.6
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• pp.1-8
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• 2010

As ubiquitous computing is evolving, RFID/USN technology is largely applied to various fields. Although there has been much research on the improvement of educational environment using RFID/USN technology, there has been little research on the learning improvement using it. So, in this paper, we used RFID/USN technology to find out the location and situation of students for Chinese situation learning system. We developed a mobile RFID middleware for Chinese situation learning system reflecting Chinese characteristics compared with English on PDA. In USN environment, we designed a USN system, which gets the situation information through a sensor network with sensors and sends them for helping learners study in situation learning. We took a pilot test to a small group for the analysis of the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1223-1228
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• 2012

The use of a mobile agent in hospital environment offers an opportunity to deliver better services for patients and staffs. Furthermore, medical errors will be reduced because M-health system helps to verify the medical process. Optimized security protocols and mechanisms are employed for the high performance and security. Finally, a challenge in the near future will be converge the integration of Ubiquitous Sensor Network (USN) with security protocols for applying the hospital environment. We proposed secure authentication and protocol with Mobile Agent for ubiquitous sensor network under healthcare system surroundings.

• ETRI Journal
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• v.30 no.5
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• pp.644-652
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• 2008

In this paper, a low-power CMOS interface circuit is designed and demonstrated for capacitive sensor applications, which is implemented using a standard 0.35-${\mu}m$ CMOS logic technology. To achieve low-power performance, the low-voltage capacitance-to-pulse-width converter based on a self-reset operation at a supply voltage of 1.5 V is designed and incorporated into a new interface circuit. Moreover, the external pulse signal for the reset operation is made unnecessary by the employment of the self-reset operation. At a low supply voltage of 1.5 V, the new circuit requires a total power consumption of 0.47 mW with ultra-low power dissipation of 157 ${\mu}W$ of the interface-circuit core. These results demonstrate that the new interface circuit with self-reset operation successfully reduces power consumption. In addition, a prototype wireless sensor-module with the proposed circuit is successfully implemented for practical applications. Consequently, the new CMOS interface circuit can be used for the sensor applications in ubiquitous sensor networks, where low-power performance is essential.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.04a
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• pp.181-186
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• 2009

Recently, the consuming efficiency of energy and natural resources has been a hot issue because of the continuous increasing of energy consumption and soaring of international oil prices. We tried to seek an action plan for the government's new paradigm 'Low-Carbon, Green Growth' by consuming energy efficiently and improving in energy management based on ubiquitous IT technologies. In this study, the library survey method is adopted for this study and IP-USN(internet protocol based ubiquitous sensor network) is considered as a core technology among various ubiquitous IT technologies. The purpose of this study is to deliver a method of energy management through integrating the context information gathered from sensors with digital space models and visualizing them together. The details are to survey the technologies of digital space modeling, USN based monitoring, building energy management and to integrate these technologies all together. This study will contribute to the enhancement of efficient building energy management by grasping the accurate situation of energy consuming in the building in realtime and minimizing unnecessary energy wastes.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.6
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• pp.42-47
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• 2008

In this article a novel constant amplitude precoding for impulse UWB system is proposed. According to IEEE 802.15.4a, impulse UWB can be used in indoor localization and sensor data transmission. Most USN(ubiquitous sensor networks) needs multiple access. However impulse UWB system has a limited capability to detect superpositioned signal induced by multiple access. To overcome this problem we have adopted the concept of CAMC(Constant Amplitude Multi-Code) deviced by Wada and Kim. The proposed system consists of systematic constant amplitude precoding and LDPC decoding. And this system shows a good BER performance in computer simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.10
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• pp.968-974
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• 2006

We are moving into the era of ubiquitous computing. Ubiquitous Sensor Network (USN) is a base of such computing paradigm, where recognizing the identification and the position of objects is important. For the object identification, RFID tags are commonly used. For the object positioning, use of sensors such as laser and ultrasonic scanners is popular. Recently, there have been a few attempts to apply RFID technology in robot localization by replacing the sensors with RFID readers to achieve simpler and unified USN settings. However, RFID does not provide enough sensing accuracy for some USN applications such as robot navigation, mainly because of its inaccuracy in distance measurements. In this paper, we describe our approach on achieving accurate navigation using RFID. We solely rely on RFID mechanism for the localization by providing coordinate information through RFID tag installed floors. With the accurate positional information stored in the RFID tag, we complement coordinate errors accumulated during the wheel based robot navigation. We especially focus on how to distribute RFID tags (tag pattern) and how many to place (tag granularity) on the RFID tag-floor. To determine efficient tag granularities and tag patterns, we developed a simulation program. We define the error in navigation and use it to compare the effectiveness of the navigation. We analyze the simulation results to determine the efficient granularities and tag arrangement patterns that can improve the effectiveness of RFID navigation in general.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8A
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• pp.618-624
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• 2009

In the evolution from wireless sensor networks(WSNs) to ubiquitous sensor networks(USNs), technologies that can support intensive data-traffic loads, large number of users, improved interoperability, and extreme longevity are required. Therefore, efficient communication time coordination control and low power consumption becomes one of the most important design goals for USN MAC protocols. So far several time division multiplexed (TDM) MAC protocols have been proposed. However, since the pros and cons of existing protocols are not easy to analyze, it becomes a challenging task to design improved TOM MAC protocols. Based on this objective, this paper provides a novel protocol analysis along with a message complexity derivation and comparison of the existing TDM MAC protocols.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.227-228
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• 2008

노인들이 주거하는 실버타운에는 노인들의 건강 관리가 가장 중요하다. 이러한 노인들은 갑작스럽게 생체 신호의 변화나 건강 상태가 나빠질 수 있다. 대부분의 실버타운은 의료시설 외의 다른 장소에서 노인들의 건강 상태를 확인할 수 없다. 따라서 본 논문에서는 실버타운에서 노인들의 생체 정보 및 응급상황을 언제, 어디서나 모니터링 할 수 있는 USN(Ubiquitous Sensor Network)시스템을 설계 및 구현한 연구를 소개한다. 또한, 실버타운 환경을 고려한 라우팅 알고리즘을 소개한다.