• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.41-44
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• 2003

We propose portable equipment that monitors current and voltage of high-potential power transmission lines. In the equipment, a current and voltage sensor are attached to an insulator that supports a power transmission line: A clamped to the power line and the detected current signal is transmitted to the ground station by a wireless optical link using transmission line is detected by a high resistance element, zinc oxide (ZnO). That acts as a potential divider between the power line and ground. We make an experimental device for 66kV power line and demonstrate that it can monitor currents proposed equipment is small-sized, light, and inexpensive in comparison with the conventional CT (current transformer) and PT (potential transformer) since it does not require high potential insulators and magnetic cores, further, the equipment is easily installed owing to its small size and its simple structure.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.138-143
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• 2002

This paper describes a framework for extending GIS databases to support moving object data type and query language. The rapid progress of wireless communications, positioning systems, and mobile computing devices have led location-aware applications to be essential components for commercial and industrial systems. Location-aware applications require GIS databases system to represent moving objects and to support querying on the motion properties of objects. For example, fleet management applications may require storage of information about moving vehicles. Also, advanced CRM(Customer Relationship Management) applications may require to store and query the trajectories of mobile phone users. In this trend, maintaining consistent information about the location of continuously moving objects and processing motion-specific queries is challenging problem. We formally define a data model and query language for mobile objects that includes complex evolving spatial structure, and propose core algebra to process the moving object query language. Main profit of proposed moving objects query language and algebra is that proposed model can be constructed on the top of GIS databases.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.491-494
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• 2018

Radio base stations, which are widely distributed across large areas, have many difficulties in managing them. Unmanned radio base stations in remote mountains are having a hard time accessing them in case of emergencies. Major telephone service providers only remotely control incoming and outgoing information and local small business partners responsible for maintaining actual facilities do not possess such technologies, so they are each checked during field visits. In this study, in order to monitor temperature, humidity, fire condition, and power operation at a wide range of radio base stations, real-time monitoring is carried out at the office of Klaus server through real-time monitoring.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.315-321
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• 2009

Remote water meter monitoring is essential in U-city applications, whoγe digital water meter is a key component. While there are several kinds of water meters, the way to use has sensors has the merit of better preciseness, but the drawback of more power consumption. In this paper, we suggest an advanced sensing algorithm to diminish the power consumption while keeping the quality of preciseness. Our approach is to use less precise hall sensor for detecting the start of water impeller rotation with lower power consumption. During the rotation, a high precision hall sensor is used to meter the amount of water consumption. Our algorithm is analyzed to get 2 times lower power consumption than the previous algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.231-234
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• 2001

OBD-II regulations are already effective in many countries. The California Air Resources Board(CARB) first issued regulations in 1985 for the 1988 model year, known as OBD-I, and required the vehicle's engine management computer to warn the driver by means of a dash-mounted light if a malfunction occurred in either the oxygen sensor, the exhaust gas recirculation(EGR) valve or the evaporative emission system purge solenoid, and to store information on troubles that have no recurrent characteristics. This paper presents two methods of wireless monitoring OBD signal, which is one of the ECU output for self diagnostic measurement. RF module is used to monitor ECU's Self diagnostic signal remotely. Two kinds of measurement systems which are based on micro-controller(80C196KC) for portable detection and PC for sever are considered for receiving the RF signal. Therefore, possibility of real-time monitoring of ECU's self diagnostic signal remotely is verified on this paper.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.98-107
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• 2003

In this study, a survey of time synchronization methods between the remote places. Generally, there are many kinds of time synchronization methods for distant places and they can be grouped three categories according to the type of time transfer methods. The three methods are ground based network, GPS/NAVSTAR and geostationary satellite. Especially, the relay base stations for wireless digital communication are operated based on the timing signal service of the GPS/NAVSTAR satellite network. And as the back-up of the timing signal service of the GPS/NAVSTAR, the geostationary satellite based time synchronization method have researched. In this short paper, the brief explanations about each category were presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4618-4639
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• 2018

One of the most innovative paradigms for the next-generation of wireless cellular networks is the cloud-radio access networks (C-RANs). In C-RANs, base station functions are distributed between the remote radio heads (RHHs) and base band unit (BBU) pool, and a communication link is defined between them which is referred as the fronthaul. This leveraging link is expected to reduce the CAPEX (capital expenditure) and OPEX (operating expense) of envisioned cellular architectures as well as improves the spectral and energy efficiencies, provides the high scalability, and efficient mobility management capabilities. The fronthaul link carries the baseband signals between the RRHs and BBU pool using the digital radio over fiber (RoF) based common public radio interface (CPRI). CPRI based optical links imposed stringent synchronization, latency and throughput requirements on the fronthaul. As a result, fronthaul becomes a hinder in commercial deployments of C-RANs and is seen as one of a major bottleneck for backbone networks. The optimization of fronthaul is still a challenging issue and requires further exploration at industrial and academic levels. This paper comprehensively summarized the current challenges and requirements of fronthaul networks, and discusses the recently proposed system architectures, virtualization techniques, key transport technologies and compression schemes to carry the time-sensitive traffic in fronthaul networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.2
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• pp.480-497
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• 2012

As a new business concept, machine-to-machine (M2M) communications are born from original telemetry technology with the intrinsic features of automatic data transmissions and measurement from remote sources typically by cable or radio. M2M includes a number of technologies that need to be combined in a compatible manner to enable its deployment over a broad market of consumer electronics. In order to provide better understanding for this emerging concept, the correlations among M2M, wireless sensor networks, cyber-physical systems (CPS), and internet of things are first analyzed in this paper. Then, the basic M2M architecture is introduced and the key elements of the architecture are presented. Furthermore, the progress of global M2M standardization is reviewed, and some representative applications (i.e., smart home, smart grid and health care) are given to show that the M2M technologies are gradually utilized to benefit people's life. Finally, a novel M2M system integrating intelligent road with unmanned vehicle is proposed in the form of CPS, and an example of cyber-transportation systems for improving road safety and efficiency are introduced.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.203-206
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• 2005

차량 진단 기능이 탑재된 원격 서버, 제어 신호 중계 기능을 가진 휴대폰용 어플리케이션, 그리고 신호 변환을 위한 converting 보드를 사용하여 기존의 차량진단기(scanner)와 동일한 기능을 가지는 원격차량진단 시스템을 제안한다. 원격 서버에서 직접 차량 진단 기능을 수행함으로써 진단 이력에 대한 자동 관리가 가능하며 다양한 부가 서비스를 연계하여 제공할 수 있다. 또한 신규 차종에 대하여 원격 서버 프로그램의 변경으로 대응이 가능하므로 기존 방식처럼 신규 차종에 대한 개별 upgrade가 필요 없다. 제안한 방식은 저가의 진단 시스템 구축이 가능하므로 영업소에서만 사용되던 차량 진단기를 개별 사용자가 사용할 수 있게 해준다. 또한 bluetooth의 Serial Port Profile을 기반으로 휴대전화기와 converting 보드간의 선을 제거함으로써 사용자가 간단하게 진단 어플리케이션이 탑재된 bluetooth handset에서 진단을 할 수 있다. 실험을 통하여 제안한 방식의 실제 환경에서 잘 동작함을 검증하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1275-1280
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• 2018

We made a smartphone interlocking location tracking streetlight and remote display device to compensate the defect of real time identifiable CCTV streetlights and child safety notification applications. It controls brightness of LED by detecting the surrounding brightness and objects with ultrasonic sensor and illuminance senor. The CCTV receives the location of smartphone by Bluetooth and takes the target of the location. It realizes a wireless transmission system that the video is upload to the tablet PC via WiFi.