• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.909-914
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• 2011

In these days, according to the enhancement of the mobile communication technologies, location based services using the location and movements are vitalized. In this paper, we develop a private vehicle tracking system for garbage truck operation management using GPS and CDMA communication and Open map interface. The terminal equipment attached in vehicle receives the GPS signals and detect the position data including time, longitude, latitude, and altitude. And the terminal sends these data to the server PC through CDMA cellular network in fixed period. The server saves these data into database to process in map server program with which we can view real-time trace of moving vehicle. We apply our system to public garbage truck managing operation and we can increase operation efficiency by examine real-time working and moving path and by present reasonable operation rout.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.37-42
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• 2017

Over the next decade, there are estimated to be 250 billion IoT devices in the future, and a variety of new services and device markets are expected to be created via a new network connection. However, it is difficult to accommodate various sensors and IoT devices, such as product and installation environments, for existing IP/SIP/IMS cameras and video door phone. Additionally, recently, sensors and actuators that can accommodate IoT technology and standards are continually updated. In addition, this paper has developed an SIP/IMS intelligent gateway to flexibly accommodate IoT related equipments and to interface with ZigBee/Z-Wave/NFC endpoints in addition to the gateway basic functions. This intelligent gateway will contribute to the development of the IMS system to replace the VoIP system with the IMS equipment due to the growth of the IMS market.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.351-354
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• 2011

Home network system makes it available for controlling inside home and for controlling from outside as well with personal computer, cellular phone or smart phone, by connecting diverse information equipments within home such as lighting, gas, and heating equipments with network Integrated server and wall-pad, which form home network system, have demerits as saying of being high-priced and of needing to implement network infrastructure. Also, there is also risk, which is unavailable for controlling equipments inside home, or can cause malfunction of equipments given the occurrence of a problem about integrated server This study suggested the intelligent home network system, which uses smart phone of supplementing these merits of home network system. It substituted high-specification input & output equipment in the currently and widely supplied smart phone for display and touch screen, which are user interface part of the existing wall-pad, and suggest the common home network system by concentrating management and control function of home network on smart phone.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.827-830
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• 2011

In this paper, a wind speed & direction module and the DSP(Digital Signal Processor) sensor interface circuit board are proposed. This DSP system accepts and process the informations from a wind speed & direction module, the atmospheric pressure sensor, the ambient air temperature sensor and transfers it to the PC monitering system. Especially, a wind speed & direction module and a DSP hardware are directly designed and applied. A wind speed & direction module have a construction that it have four film type RTD(Resistive Temperature Detectors) or film type Piezo sensors adhered around the circular metal body for obtaining vector informations about wind. By this structure, the module is enabled precise measurement having a robustness about vibration, humidity, corrosion. A sensor signal processing circuit is using TMS320F2812 TI(Texas Instrument) Corporation high speed DSP.

• Tribology and Lubricants
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• v.34 no.2
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• pp.49-54
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• 2018

Hydraulic reciprocating seal has been widely used to prevent fluid leakage in hydraulic systems. Also, hydraulic reciprocating seal plays a significant role to provide lubricant film at contacting interface to minimize tribological problems due to sliding with counter material. To predict lifetime of hydraulic reciprocating seal, quantitative understanding of wear characteristics with respect to operating conditions such as normal force and sliding speed is needed. In this work, effect of sliding speed on wear of polyurethane (PU) hydraulic reciprocating seal were experimentally investigated using a pin-on-disk tribo-tester. The wear characteristics of PU specimens were quantitatively determined by comparing the confocal microscope data before and after test. It was found that the wear rate of PU specimens decreased from $4.9{\times}10^{-11}mm^3$ to $1.1{\times}10^{-11}mm^3/Nm$ as sliding speed increased from 120 mm/s to 940 mm/s. Also, it was observed that the friction decreased slightly as the sliding speed increased. Improvement of lubrication state with increasing sliding speed was likely to be responsible for this enhanced friction and wear characteristics. This result also suggests that decrease in sliding distance between PU elastomer and counter materials at lower sliding speed is preferred. Furthermore, the quantitative assessment of wear characteristics of PU specimen may be useful in prediction of lifetime of PU hydraulic reciprocating seal if the allowed degree of wear for failure of the seal is provided.

• Journal of Drive and Control
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• v.14 no.2
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• pp.23-29
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• 2017

In this study, a flexible multi-body dynamic simulation model of a knuckle boom crane is developed to evaluate the stress of spindle and rack gears under dynamic working conditions. It is difficult to predict potential critical damage to a knuckle boom crane if only the static condition is considered during the development process. To solve this issue, a severe working scenario (high speed with heavy load) was simulated as a boundary condition for testing the integrity of the dynamic simulation model. The crane gear model is defined as a flexible body so contact analysis was performed. The functional motion of a knuckle boom crane is generated by applying forces at each end of the rack gear, which was converted from hydraulic pressure measured for the experiment. The bending and contact stress of gears are theoretically calculated to validate the simulation model. In the simulation, the maximum stress of spindle and rack gears are observed when the crane abruptly stops. Peak impact force is produced at the contact interface between pinion and rack gears due to the inertia force of the boom. However, the maximum stress (bending/contact) of spindle and rack are under the yield stress, which is safe from damage. By using the developed simulation model, the experiment process is expected to be minimized.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1615-1622
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• 2016

This research aims to develop a voyage performance monitoring system based on international standards. The developed system is equipped with an electronic navigational chart(ENC) that provides onshore and offshore information, as well as supports standardized interfaces with navigational equipment, such as a gyro compass, a differential global positioning system(DGPS), and an automatic identification system(AIS), to monitor the navigation route in real time. In addition, the proposed system adopts a car navigation system to provide a graphical user interface, an intuitive menu-driven configuration, and an easy guide for safer sea navigation. The system, interfaced with the gyro compass and DGPS, was verified without any data loss, and passed a test conducted under extreme conditions by the Korea Laboratory Accreditation Scheme(KOLAS). Finally, the system contributes to preventing collision of vessels and minimizing casualties by maximizing the convenience of mariners which a conventional system does not provide.

• Journal of Information Technology Services
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• v.3 no.1
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• pp.79-88
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• 2004

Practical use of Information Technology in present enterprise simply enterprise support do pass over known dimension and is utilizing by means for enterprise competitive power strengthening. Because of these point, a lot of kind of information systems appeared. It can be said that EIP system that many enterprises are introducing recently is concept that appear to also use information in enterprise more efficiently. If present EIP system sees construct example, segment is detected to improve some. First, should do duplicate development despite it is same function to use EIP system in wireless and web browser environment. Second, can hear management's difficulty by immense contents that happen in System Integration. We wish to solve problem that happen in development of existing EIP system using XUL and a SVG technology in this paper that aim to these. XUL is open source In language to manufacture UI that do not receive court of platform and existence and nonexistence captain rain, support wireless and web browser equipment at the same time to source that is produced once if is browser that can manufacture usable interface in web and supports XUL as user wants. SVG method is a skill that can offer convenience that is epoch-making in contents management by software that describe contents representation in source code unlike form that show because calls contents forming already in the existent bit map room and establishes to browser handles this and expresses contents. In paper, produced use of XUL and SVG by prototype to presented whether can apply XUL and a SVG technology to actuality EIP system and verifies whether this is possible and that do actuality through existent method and comparison and excellency were seen.

• Journal of Information Technology Services
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• v.16 no.2
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• pp.111-127
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• 2017

Computing Performance, sensor, storage, memory, and network costs have been steadily declining, and IoT services have recently become more active. The Internet of Things is linked with Big Data to create new business, and public institutions and corporations are hurry to import Internet of things. As the importance of the Internet of things has increased, the number of devices supporting the IoT has rapidly increased. With the development of the Internet of Things, various types of Internet services are being developed. For this reason, there is an increasing demand for IoT service designers and developers for IoT service case automatic search technology. IoT service designers can avoid duplication with existing services through service case retrieval and developers can save cost and time by combining existing reusable service equipment. This paper proposes IoT-Lite ontology for IoT and Semantic Web service to solve the above-mentioned problems. The existing ontologies for IoT, despite its many advantages, are not widely used by developers because it has not overcome the relatively slow drawbacks of increasing complexity and searching for development. To complement this, this study uses the IoT-Lite ontology introduced by W3C as a model and a semantic web service for automatic system retrieval. 3D camera, GPS, and 9-axis sensor, and IoT-Lite designed by IoT-Lite technique are integrated with the semantic technique and implemented directly.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.115-124
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• 2002

This paper presents an active auxiliary edge-resonant DC link snubber with a ringing surge damper and a three-phase voltage source type zero voltage soft-switching inverter with the resonat snubber treated here for the AC servo motor driver applications. The operation of the active auxiliary edge-resonant DC link snubber circuit with PWM voltage is described, together with the practical design method to select its circuit parameters. The three-phase voltage source type soft-switching inverter with a single edge-resonant DC link snubber treated here is evaluated and discussed for the small-scale permanent magnet (PM) type-AC servo motor driver from an experimental point of view. In addition to these, the AC motor stator current and its motor speed response for the proposed three-phase soft-switching inverter employing Intelligent Power Module(IPM) based on IGBTS are compared with those of the conventional three-phase hard-switching inverter using IPM. The practical effectiveness of the three-phase soft-switching inverter-fed permanent magnet type AC motor speed tracking servo driver is proven on the basis of the common mode current in a novel type three-phase soft-switching inverter-fed AC motor side and the conductive noise on the mains terminal interface voltage as compared with those of the conventional three-phase hard-switching inverter-fed permanent magnet type AC servo motor driver for the speed tracking applications.