• International journal of advanced smart convergence
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• v.8 no.3
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• pp.54-60
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• 2019

In this paper, a localization system for indoor objects is proposed. The proposed system consists of Beacons, LED Cells, Main Cell Controller (MCC), and Display. A Beacon is attached at each indoor object, and each LED cell has Beacon Scanner and VLC Transmitter. The Visual Light Communications (VLC) and Power Line Communications (PLC) methods are used to communicate the signals for localization of indoor objects. And the proposed system is designed, and implemented as a prototype. To certify that our propose d system can exactly localize a given indoor object, we take test for the implemented system as a p rototype. Here the location of the given indoor object is known. Test is done in two ways. The first is to check the operation of the detail of the system, and the second is the position recognition of i ndoor object. The second is the test of the implemented system to correctly detect the location of the indoor object with Beacon, while the object with Beacon is moved from location C to A. The experimental result shows that the system is exactly detect the moving locations. The system has the advantages of using previously installed power lines, and it does not need to use LAN lines or optical cables. The proposed system is usefully applied to indoor object localization area.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.159-160
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• 2019

It would be very important to localize people at risk as soon as possible in order to minimize the damage. Generally the infrastructure should be deployed additionally for indoor positioning system. In this paper, we proposed an indoor localization system for people at risk using the existing fire alarm networks. The system detects the signal of smart devices of people in danger immediately and let the main alarm controller ring all alarms in vessel and display the position. Thus, the proposed system can make the burden much less to deploy additional network and infrastructure.

• Journal of IKEEE
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• v.23 no.1
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• pp.68-73
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• 2019

This paper presents a novel fast shut-down scheme for Buck converter by using a coupled inductor. Generally, a controller for Buck converter stops generating PWM patterns in various fault cases: Overcurrent, Short circuit, or Overvoltage, but the inductor and capacitor keep supplying their stored energy to loads although the switching operations in Buck converter stopped. The stored energy in the inductor and capacitor could cause electrical stresses on breakers and safety problems. The main idea of the proposed fast shutdown scheme is to demagnetize the inductor core by using a coupled inductor, and its performance and operations are verified by using PSIM Simulation.

• International Journal of Computer Science & Network Security
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• v.21 no.8
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• pp.111-118
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• 2021

Banking systems are sensitive to data privacy since users' data, if not well protected, may be used to perform fake transactions. Blockchains, public and private, are frequently used in such systems thanks to their efficiency and high security. Public blockchains fail to fully protect users' data, despite their power in the accuracy of the transactions. The private blockchain is better used to protect the privacy of the sensitive data. They are not open and they apply authorization to login into the blockchain. However, they have a lower security compared to public blockchain. We propose in this paper a hybrid public-private architecture that profits from network virtualization. The main novelty of this proposal is the use of network virtualization that helps to reduce the complexity and efficiency of the computations. Simulations have been conducted to evaluate the performance of the proposed solution. Findings prove the efficiency of the scheme in reducing complexity and enhancing data privacy by guarantee high security. The contribution conducted by this proposal is that the results are verified by the centralized controller that ensures a correct validation of the resulted blockchains. In addition, computation complexity is to be reduced by profiting from the cooperation performed by the virtual agents.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.43-49
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• 2021

A small infrared image homing system is a tracking system that has an infrared image sensor that identifies a target through the day and night infrared image processing of the target on the ground and searches for and detects the target with respect to the main target. This paper describes the development of a board equipped with a high-speed CPU and FPGA (Field Programmable Gate Array) to identify target through real-time image processing by acquiring target information through infrared image. We propose a CPU-FPGA combining architecture for CPU and FPGA selection and video signal processing, and also describe a controller design using FPGA to control infrared sensor.

• Journal of Advanced Navigation Technology
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• v.27 no.5
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• pp.546-551
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• 2023

In this study, a beam steering measurement system was developed to perform functions such as far-field beam steering and near-field beam focusing for TX/RX modes in the near file of the AESA radar. The beam steering measurement system consists of a spherical near-field scanner, an antenna positioner, a near-field controller, a network analyzer, a radar control system, a verification radar, a simulated radio, and an AESA radar. Using the developed system, the characteristics of TX/RX patterns before and after installation of radome to AESA radar were measured, and the beam pattern was analyzed through conversion to far field-after near-field measurement.The boresight error of the radar antenna device was measured, and it was confirmed that the main lobes were formed the same before and after the simulated radar dome was mounted.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.7
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• pp.559-566
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• 2001

The sway control problem of the pendulum motion of a container hanging on the trolly, which transports containers from a container ship to trucks, is considered in the paper. In the container crane control problem, suppressing the residual swing motion of the container at the end of acceleration, deceleration or the case of that the unexpected disturbance input exists is main issue. For this problem, in general, the trolley motion control strategy is introduced and applied. In this paper, we introduce and synthesize a new type of swing motion control system in which a small auxiliary mass is installed on the spreader. The actuator reacting against the auxiliary mall applies inertial control forces to the container to reduce the swing motion in the desired manner. In this paper, we apply the $H^{\infty}$ based gain-scheduling control technique to the anti-swing motion control system design problem of the controlled plant. In this control system, the controller dynamics are adjusted in real-time according to time-varying plant parameters. And the simulation result shows that the proposed control strategy is shown to be useful for the case of time-varying system and, robust to disturbances such as winds and initial sway motion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.4
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• pp.315-324
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• 2005

VOD(video on demand) is a video service by users' order, that is, a video service on demand. That means the users can select and watch the video content that has been saved on sewer, out of broadcasting in the usual process like TV. At present the client of VOD system bases on PC. As the PC-based client uses the software MPEG decoder, the main processor specification has an effect on the capacity. Also people, who don't know how to use their PC, cannot be provided the VOD service. The purpose of this paper is to show the process of the development the VOD client system Into the embedded type with hardware MPEG-4 decoder. The main processor is the SC1200 of x86 Family in National Semiconductor with a built-in video processor and the memory is 128Mbyte SDRAM. Also, in order that the VOD service can be provided using the Internet, the Ethernet controller is included. As the hardware MPEG-4 decoder is used in the embedded VOD client system, which is developed, it can make the low capacity of the main processor. Therefore it is able to be developed as a low-price system. The embedded VOD client system is easy for anyone to control easily with the remote control and can be played through TV.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1113-1124
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• 2004

In this paper, we proposed a hardware(H/W) structure which can compress and recontruct the input image in real time operation and implemented it into a FPGA platform using VHDL(VHSIC Hardware Description Language). All the image processing element to process both compression and reconstruction in a FPGA were considered each of them was mapped into H/W with the efficient structure for FPGA. We used the DWT(discrete wavelet transform) which transforms the data from spatial domain to the frequency domain, because use considered the motion JPEG2000 as the application. The implemented H/W is separated to both the data path part and the control part. The data path part consisted of the image processing blocks and the data processing blocks. The image processing blocks consisted of the DWT Kernel fur the filtering by DWT, Quantizer/Huffman Encoder, Inverse Adder/Buffer for adding the low frequency coefficient to the high frequency one in the inverse DWT operation, and Huffman Decoder. Also there existed the interface blocks for communicating with the external application environments and the timing blocks for buffering between the internal blocks The global operations of the designed H/W are the image compression and the reconstruction, and it is operated by the unit of a field synchronized with the A/D converter. The implemented H/W used the 69%(16980) LAB(Logic Array Block) and 9%(28352) ESB(Embedded System Block) in the APEX20KC EP20K600CB652-7 FPGA chip of ALTERA, and stably operated in the 70MHz clock frequency. So we verified the real time operation of 60 fields/sec(30 frames/sec).

• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.1-17
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• 2015

A river water level monitoring system which prevents salt water damages and effectively excludes floods has been developed to contribute efficient operation of Nakdong river estuary barrage. The system can be used for monitoring upstream conditions more quickly and do appropriate responses over changes. Telemetry and telecontrols using PLCs have been built at the three sites that directly influence on the operation of barrage gates, and are linked to Nakdong river estuary barrage's IOS (Integrated Operation System) through public communication networks. By using PLC, the system can achieve even higher reliability and versatility than before as well as easy management. By power control devices, we can remotely control the power of PLCs to treat the minor troubles instantly without going on-sites. The power control devices also save data in preparation for the cases of communication failures. The system uses ADSL (FTTH) as a main network between SCADA server and PLCs, and CDMA (M2M) as a secondary network. In order to compensate security vulnerabilities of public communication network, we have installed the VPNs for secure communication between center and the observation stations, just like a dedicated network. Generally, river water level observations have been used custom-manufactured remote terminals to suit their special goals. However, in this case, we have established a system with open architecture considering the interface between different systems, the ease of use and maintenance, security, price, etc.