• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.329-337
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• 2016

With the increasing deployment of distributed generators in the distribution system, a very large search space is required when dynamic programming (DP) is applied for the optimized dispatch schedules of voltage and reactive power controllers such as on-load tap changers, distributed generators, and shunt capacitors. This study proposes a new optimal voltage and reactive power scheduling method based on dynamic programming with a heuristic searching space reduction approach to reduce the computational burden. This algorithm is designed to determine optimum dispatch schedules based on power system day-ahead scheduling, with new control objectives that consider the reduction of active power losses and maintain the receiving power factor. In this work, to reduce the computational burden, an advanced voltage sensitivity index (AVSI) is adopted to reduce the number of load-flow calculations by estimating bus voltages. Moreover, the accumulated switching operation number up to the current stage is applied prior to the load-flow calculation module. The computational burden can be greatly reduced by using dynamic programming. Case studies were conducted using the IEEE 30-bus test systems and the simulation results indicate that the proposed method is more effective in terms of saving electric charges and improving the voltage profile than loss minimization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.900-909
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• 1999

The receiving part of the RF system for the digital TRS base stations is developed in this paper. Based on the system specifications, the structure of the RF system is accomplished and its block diagram is drawn. The RF system is implemented according to these block diagrams. Subsequently the RF band-pass filter, the low noise amplifier, the automatic level controlled attenuator, the frequency synthesizer and other components for the system are designed and implemented, and a main board to integrate these modules is also manufactured. To lower the noise floor of the system and suppress the RF spurious noise, a PCB layout is performed carefully. For each module consisting of the RF system and the entire system, the performance tests are accomplished to check the specifications.

• Journal of IKEEE
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• v.23 no.2
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• pp.474-478
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• 2019

In this paper, we analyze the degradation of receiving sensitivity due to the coupling between digital noise and mobile handset antenna using characteristic mode. First, we analyze the coupling mechanism between the antenna and digital noise, and analyze the role of the decoupling capacitor of the ground signal line, which is one of the ways to improve the antenna receiving sensitivity degradation due to camera noise. For the analysis, the digital signal line and the ground line of the FPCB of the camera module are modeled as a loop type feeder that excites the characteristic mode of the PCB ground, and improved model which has a ground line with a capacitor are analyzed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.5
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• pp.325-335
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• 2018

We herein present a study on the active phased array antenna for receiving satellite broadcasting that can electrically align its polarization to that of target transmitters in its moving condition or in the Skew angle arrangement of the broadcasting satellite receiver. Hence, we have developed an active phased array structure composed of the self-developed Vivaldi antenna and multifunction core (MFC) chip, receiving RF front end module, and control units. In particular, the new Vivaldi antenna designed in the Ku-band of 10.7 - 14.5 GHz to receive one desired polarization mode such as the horizontal or vertical by means of an MFC chip and other control units that can control the amplitude and phase of each antenna element. The test results verified that cross-polarization property is 20 dB or higher and the primary beam can be scanned clearly at approximately ${\pm}60^{\circ}$.

• The Journal of the Acoustical Society of Korea
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• v.22 no.7
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• pp.592-602
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• 2003

This paper aims to describe the basic structure of novel object-based 3D audio broadcasting system To overcome current uni-directional audio broadcasting services, the object-based 3D audio broadcasting system is designed for providing the ability to interact with important audio objects as well as realistic 3D effects based on the MPEG-4 standard. The system is composed of 6 sub-modules. The audio input module collects the background sound object, which is recored by 3D microphone, and audio objects, which are recorded by monaural microphone or extracted through source separation method. The sound scene authoring module edits the 3D information of audio objects such as acoustical characteristics, location, directivity and etc. It also defines the final sound scene with a 3D background sound, which is intended to be delievered to a receiving terminal by producer. The encoder module encodes scene descriptors and audio objects for effective transmission. The decoder module extracts scene descriptors and audio objects from decoding received bistreams. The sound scene composition module reconstructs the 3D sound scene with scene descriptors and audio objects. The 3D sound renderer module maximizes the 3D sound effects through adapting the final sound to the listner's acoustical environments. It also receives the user's controls on audio objects and sends them to the scene composition module for changing the sound scene.

• Korean Journal of Optics and Photonics
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• v.28 no.3
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• pp.116-121
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• 2017

In this paper, a Raman spectrometer is designed to detect chemicals contaminating the ground. The system is based on Raman spectroscopy, which is spectral analysis of scattered light from chemicals, induced by a laser. The system consists of a transmitting-optics module with a laser to induce Raman-scattered light from the sample, a receiving-optics module to collect the scattered light, and a spectrograph to separate the collected light into a wavelength spectrum. The telescope, a part of the receiving-optics module, is designed to produce a focal spot in the same position for variable measurement distances using the code V simulator, considering the distance change between the system and the road. The Raman spectra of 12 chemicals on a glass surface and on a concrete sample were measured. Intensity differences between the Raman spectra acquired on a glass surface and on a concrete sample were observed, but the characteristics of the spectra according to the chemicals on them were similar. Additionally, the Raman spectrum of PTFE (polytetrafluoroethylene) was measured at various distances. The measured and simulated optical throughputs were similar. In conclusion, it is confirmed that with this system the Raman spectrum can be measured, irrespective of the distance change.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.72-80
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• 2009

By the advent of an era of digital convergence, the user-friendly DTV graphic user interface (GUI) techniques become very important because of the explosive consumption of DTV receiving modules. This paper describes the design and implementation of GUI of menu-driven type for the operation of HDTV MPEG module. The designed GUI is convenient and user-friendly. Main menu is created by forming a new window and is located on the top area of the window in the structure of 1 by 3 matrix. Thus main menu, sub-manu, and lower-level menu can be displayed on a screen. The menu-driven DTV GUI was acomplished by using new styles and icons.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.494-496
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• 2002

A bi-directional and multi-channel wireless telemetry capsule, 11mm in diameter, is presented that can transmit video images from inside the human body and receive a control signal from an external control unit. The proposed telemetry capsule includes transmitting and receiving antennas, a demodulator, decoder, four LEDs, and CMOS image sensor, along with their driving circuits. The receiver demodulates the received signal radiated from the external control unit. Next, the decoder receives the stream of control signals and interprets five of the binary digits as an address code. Thereafter, the remaining signal is interpreted as four bits of binary data. Consequently, the proposed telemetry module can demodulate external signals so as to control the behavior of the camera and four LEDs during the transmission of video images. The proposed telemetry capsule can simultaneously transmit a video signal and receive a control signal determining the behavior of the capsule itself. As a result, the total power consumption of the telemetry capsule can be reduced by turning off the camera power during dead time and separately controlling the LEDs for proper illumination of the intestine.

• Convergence Security Journal
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• v.10 no.2
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• pp.27-35
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• 2010

We implemented an application system which is able to verify visitor identification for remote bundle control based on OSGi and web camera control using embedded linux system. This system are designed open Oscar framework by porting java on the embedded linux system and implemented web camera system in local area networks. Also This system can verify information of visitor from receiving the data of RFID reader and designed the wireless internet system in home. Basically, in this paper we expect that home network system development and the period of application service development are reduced with integrated service provision based on OSGi.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.17-22
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• 2009

A switch or circulator is used for distinguishing between the paths of transmitter and receiver in TDD systems. If the isolation between Tx and Rx paths is low in TDD systems, the output signal of the ransmitter acts as an interferer to the receiver even if the transceiver operates on the receiver mode. In this paper we propose a method to get high isolation characteristics between transmitting and receiving paths in TDD systems. We implement the module with a proposed improving method to verify the effect of the isolation improvement and the experimental results are presented. The isolation improvement of above 44.8 dB over the frequency bandwidth of 30 MHz is obtained from the implemented isolation improvement module.