• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.109-117
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• 2010

With the advent of new technologies such as HSDPA, WiBro(Wireless Broadband) and personal devices, we can access various contents and services anytime and anywhere. A location based service(LBS) is essential for providing personalized services with individual location information in ubiquitous computing environment. In this paper, we propose mapping algorithm for error compensation of indoor localization system. Also we explain filter and indoor localization system. we have developed mapping algorithms composed of a map recognition method and a position compensation method. The map recognition method achieves physical space recognition and map element relation extraction. We improved the accuracy of position searching. In addition, we reduced position errors using a dynamic scale factor.

• Spatial Information Research
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• v.21 no.3
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• pp.1-10
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• 2013

Indoor space is a new horizon of spatial information services. With recent progress of indoor positioning technologies and mobile devices such as smart phones, indoor spatial information services become available and an emerging market. Accordingly, exchanging and sharing indoor spatial information between independent services become an important issue. For this reason, a standardization working group, called IndoorGML has been launched last year in OGC with the aim of publishing IndoorGML standard by September, 2013. Its primary goal is to provide a framework for representing network topology in indoor space, which is a fundamental element of indoor LBS. In this paper, we will explain the basic concepts of indoorGML and discuss the modeling issues. And several application use-cases of IndoorGML will be also presented in this paper.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.2
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• pp.209-214
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• 2016

In an environment of IoT services, sensors to track things and human activities are included as an essential element and smart phone is actively used as a means of collecting and processing information from sensors. Especially, wireless communication and NFC provided by the smart phone are key technologies for exchanging information between participants of IoT service. In this paper, we propose and implement the smart attendance checking system based on BLE using a beacon for improving the quality of a university lecture by processing attendance information automatically. Proposed system uses the beacon sensor for being aware of attendance information and the smart phone for receiving and processing this information. The implemented system has the benefit to improve the lecture quality because a professor can minimize attendance checking time and spend a lot of time on the lecture.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.53-60
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• 2017

Most of present ultrasonic distance measurement technologies are based on the measurement of the TOF (: Time of Flight), the elapsed time during which the ultrasonic wave travels from its transmitter to receiver, to evaluate the distance the wave travels during that time. In this case, high distance measurement accuracy requires an accurate measurement of TOF. In order to acquire an accurate TOF, this paper proposes a method that produces the TOF by using a mathematical model of the received signal obtained from a mathematical model of ultrasonic transducer. The proposed method estimates the arrival time of the received signal retrospectively by comparing its wave form obtained after triggering point with its mathematical model in the sense of least-square. Experimental result shows that the effect of variation of triggering point can be decreased by implementing the proposed method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.277-282
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• 2020

The construction of medium-and large-sized microgrid systems by unit area, which is being promoted worldwide, is being developed and expanded in the form of efficient operation of electric grids and independent operation in preparation for power emergencies. Therefore, for the development of the domestic electricity industry, it is urgent to analyze the current status and technology of relevant international standardization, and to make international standardization of domestic standard (draft) on the matters that need to be enacted and newly established. Campus microgrid implements smart grid element technologies such as Integrated Energy Management System(EMS), Distributed Power(DG), Energy Storage System(ESS), Demand Response(DR), and Electric Vehicle(EV) in a university campus. As a system that reduces energy use and improves energy use efficiency and energy independence, standardization is established to secure interoperability and reliability of such systems.

• Journal of Ocean Engineering and Technology
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• v.27 no.4
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• pp.1-8
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• 2013

Many PE (pre-erection) blocks are supported by wooden, concrete, or steel supports when they are stocked in the outdoor areas of a shipyard. Their positions and numbers are planned on the basis of the workers' experience. Recently, many shipyards have been making PE blocks with various shapes and weight distributions because of the variety of ships and building technologies. Therefore, it is now necessary to deal with blocks that they have no experience with. We propose a method to conveniently and quickly evaluate the structural safety of PE block supports, without the need for special knowledge and technology related to structural analysis. This method can reduce the large number of man hours (MH) normally needed for the analysis. The three-dimensional grillage analysis is performed for a simplified grillage model of a PE block. For efficiency, the grillage model of the PE block is automatically built from its three-dimensional CAD model, and its weight is also automatically distributed on the grillage model. The integrated system has been comprehensively implemented to perform the grillage analysis for the reaction forces on block supports. This paper describes how to make a grillage model of a PE block and estimate the weight distribution of the block on this grillage model. These steps are verified by comparing the supports reaction forces to those of the 3D finite element analysis for the PE blocks that are provided by a shipyard.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.3
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• pp.252-272
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• 2017

Fuel cell systems have to satisfy acceptable operating reliability, sufficient lifetime and price to enter the market in competition with existing products. Fuel cells are made up of complex element technologies and various problems related to the failure of the components can affect the reliability and safety of the system. This problem can be overcome by introducing a monitoring and supervisory control system in addition to automatic control to detect the failure of the fuel cell quickly and properly diagnose the performance degradation. For the fault detection and diagnosis of polymer electrolyte fuel cells, the model based method using the theoretical superposition value and the non-model based method of checking the signal tendency or the converted signal characteristic can be applied. The methods analyzed in this paper can contribute to the development of integrated monitoring and control technology for the whole system as well as the stack.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.261-264
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• 1997

Joints and terminations for 345kV Oil Filled $1C{\times}2000mm^2$ cable have been developed and tested including BPT (Bellows Pressure Tank) on the bases of various ultra-high voltage technologies. Electrical design was performed by using Finite Element Method. The type test certified by KEPCO (Korea Electric Power Corporation) has been performed as the final stage of development. In order to confirm the reliability of long-term life for 30 years, load cycle test was conducted for 30 days with good result. As the result, the techniques we obtained from this development are applicable to higher voltage level systems (i.e. 765 kV).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.573-581
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• 2019

In the era of the 4th Industrial Revolution, the necessity of training advanced engineering personnel with convergent creativity to handle technologies such as artificial intelligence, big data, and the internet of things (IoT) is increasing. In this paper, a new approach of engineering education based on academia-industrial cooperation and design-centered teaching technique for the students who need to learn practicable engineering skill with convergent creativity for the fourth industrial age is presented. It analyzes the strengths and weaknesses of the existing engineering education innovation activities, presents the practical necessities based on the experience of the educational system and the requirements of the educational environment, and analyzes the existing activities and the new roles. In particular, we discuss how to combine student-centered teaching methodology for effective design education, which is a key element of innovative engineering education. Most of the presented methods are verified by the authors' needs and effects in the education field.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.1
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• pp.117-123
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• 2012

Many nations have been launched their own earth observation satellites due to much interest in space exploration. Because of this, the number of high resolution satellite are increasing day by day. With the development of web environment, general users have easy access to satellite images. The research conducted a basic study about web-based satellite photogrammetry in order to determine three dimensional coordinates easily without having profound knowledge of satellite sensor modeling. Various element technologies were analyzed to decide three dimensional coordinates by using high resolution satellite images in web environment, and case studies were conducted by using IKONOS satellite images. By applying parallel projection model, which is one of sensor modeling methods, epipolar image was created and prototype form of program that can decide three dimensional location in web environment was implemented. Through this, general users could decide three dimensional location easily in web environment and knew that already existed spatial information can be renewed and used in service area.