• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.16-22
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• 1994

In this paper, transmitter and receiver modules for free space optical interconnection are implemented and characterized. In the transmitter module, bias circuitry which inject current into the direct modulated laser diode is fabricated and in the receiver module, p-i-n diode is integrated with an MMIC amplifying stage. Laser diode has a direct-modulated bandwidth of 2 GHz at 1.4 Ith bias while p-i-n diode and amplifying stage has a bandwidth of 1.3 GHz and 1.5 GHz, repectively. Optical interconnection has a bandwidth of 1.3 GHz and linearly transmit modulated voltage signal up to 1.5 Vp-p. Measured loss of optical interconnection is 5dB which is composed of optoelectronic conversion loss of 15 dB, electrical impedance mismatch loss of 6.7 dB in transmitter module and gain of 18 dB in receiver module. Seperation between transmitter and receiver can be extended up to 50 cm by using a lens.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.262-265
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• 2012

In this paper, a Ka-band 8 W power amplifier module with WR-28 waveguide input and output ports is implemented and measured using four 2 W power amplifier modules and 4:1 waveguide power combiners with high isolation of 25 dB at 35 GHz. The 2 W power amplifier modules are fabricated using waveguide-to-microstrip transitions and show output power of 32.5~33.3 dBm and power gain of 26.9~28.7 dB at 35 GHz. Four 2 W power amplifier modules are combined through 4:1 waveguide power combiners with resistive septum and the combined power shows 39.0 dBm(8 W) under 6 V drain bias and 39.6 dBm(9.1 W) under 6.5 V drain bias at 35 GHz.

• Spatial Information Research
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• v.23 no.4
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• pp.33-46
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• 2015

The fact that the limits of information recency, diversity, and usability are mainly caused by the supply oriented geospatial data and service development is commonly recognized. It is recently tried to overcome the limits by facilitating user experience and VGI(Volunteered Geographic Information) in several geospatial web services. This study suggests conceptual architecture and service scenario for geospatial collaborative platform prototype through review and examination of previous researches. The prototype, composed of 4 unit modules: 3D POI Creation Module, 3D POI Application Module, 3D POI/Event Management Module, 3D POI/Event Monitoring Module, provides the capability of collaboratively dealing with geospatial work. The suggested service scenario is demonstrated by developing prototype for the service modules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.357-358
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• 2005

Compact power amplifier modules (PAM) for WCDMA/KPCS and GSM/WCDMA dual-band applications based on multilayer low temperature co-fired ceramic (LTCC) substrates are presented in this paper. The proposed modules are composed of an InGaP/GaAs HBT PAs on top of the LTCC substrates and passive components such as RF chokes and capacitors which are embedded in the substrates. The overall size of the modules is less than 6mm $\times$ 6mm $\times$ 0.8mm. The measured result shows that the PAM delivers a power of 28 dBm with a power added efficiency (PAE) of more than 30 % at KPCS band. The adjacent-channel power ratio (ACPR) at 1.25-MHz and 2.25-MHz offset is -44dBc/30kHz and -60dBc/30kHz, respectively, at 28-dBm output power. Also, the PAM for WCDMA band exhibits an output power of 27 dBm and 32-dB gain at 1.95 GHz with a 3.4-V supply. The adjacent-channel leakage ratio (ACLR) at 5-MHz and 10-MHz offset is -37.5dBc/3.84MHz and -48dBc/3.84MHz, respectively. The measured result of the GSM PAM shows an output power of 33.4 dBm and a power gain of 30.4 dB at 900MHz with a 3.5V supply. The corresponding power added efficiency (PAE) is more than 52.6 %.

• The Journal of Korea Robotics Society
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• v.8 no.4
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• pp.247-255
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• 2013

This paper shows the development of a snake robot (KAEROT-snake V) which consists of 16 1-DOF actuator modules and head module. The modules are connected serially and the joint axis of each module is rotated by $90^{\circ}$ with respect to the previous joint so that the snake robot can move in the 3D space. A tail actuator module includes slip-ring and metal connector. KAEROT-snake IV developed in prior research could move in the 3D space and climb up in a narrow pipe. But its design was not appropriate to the unstructured tough environment and its speed was somewhat slow. A new actuator module is designed to enclose all parts of the module so that any wire is not exposed. The size and weight of the new module was slightly reduced. And the rotation speed and torque of the joint was increased by about twice when compared with pre-module. An embedded controller was developed so small that it can be mounted inside the module. The performance of the developed robot was demonstrated through various locomotion experiments.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.520-528
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• 2013

A 20 mm diameter of small 5-D.O.F. force sensor has been developed for applications in MR-field Optical intensity modulation was adopted for transducing to miniaturize the sensor structure. For its accurate sensing of 5-D.O.F. force/moment, the elastic detecting module was designed to respond independently to each force or moment component. And for small size, two optical transducing modules of 2-D.O.F. and 3-D.O.F. were designed and integrated with the detecting module where optical fibers were arranged in parallel to make the sensor small. It is confirmed by calibration test that the detecting modules deforms linearly and independently to the input force. The results of evaluating test show that the range and resolution of forces are ${\pm}4$ N and 0.94~7.1 mN and the range and resolution of moments are ${\pm}120N{\cdot}mm$ and $0.023{\sim}0.034N{\cdot}mm$.

• ETRI Journal
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• v.26 no.1
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• pp.57-60
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• 2004

We propose an inductive compensation method for a surface-mountable 10 Gbps photoreceiver module. Since many typical 10 Gbps photoreceiver modules consist of a photodetector and low-noise pre-amplifier, the impedance mismatch between the photodetector and pre-amplifier, as well as package parasitics, may reduce the frequency bandwidth. In this paper, we inserted an inductive component between the photodetector and pre-amplifier in order to create frequency bandwidth expansion. From the measurement results, we have found that the proposed technique can increase the -3 dB bandwidth about 4.2 GHz wider compared with an uncompensated module. And, from a bit-error rate (BER) test, we observed -15.7 dB sensitivity at $10^{-12}$ BER. This inductive compensation can be implemented easily and is compatible with common manufacturing processes of photoreceiver modules.

• New & Renewable Energy
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• v.16 no.1
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• pp.41-46
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• 2020

The share of agrophotovoltaics in the "renewable energy 3020", which is the Korean government policy for revitalizing new and renewable energy, is increasing gradually. In this study, the distribution of solar radiation received by crops growing on virtual farmland under a range of conditions, such as module height, module angle, shading ratio, and module type, was quantified and analyzed using an Ecotect program, which allows insolation analysis during the period from spring to fall. As the module angle increases, transmissive modules increase the amount of solar radiation delivered to the lower farmland. In addition, the difference between 3x12 Cell Type and 4x9 Cells Type, which are types of photovoltaic modules used in practice, was found to be small. The analysis results can be used as a design standard for the future establishment of agrophotovoltaic systems.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.73-81
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• 2019

Various 3D contents are being developed using Unity 3D game engine. In this paper, the 3D content of horseback riding game, the first VR game in the country, is designed and developed. The existing riding simulator is investigated and compared to the VR riding game developed. We consider various games developed using Unity 3D game engine and serve previously developed tangible games. It is expected that development of VR riding games will prepare a new chapter in VR experience-type games. We propose the content development environment and scenario of VR riding game and present the main algorithms and main modules for real-time synchronization. The developed riding game contents are deployed to the riding system and are operated for commercial use in conjunction with the riding device. Through monitoring VR riding system, problems are derived and improvement measures are proposed. We offer a variety of additional development options to make the game more realistic in the future.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.77-85
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• 2008

PDF is widely accepted as a standard document format and now it supports 3D contents as well. Within the engineering application areas, this new 3D feature may be used to support sharing of 3D documents and thus collaboration between engineering departments, suppliers and partners. In this paper, we describe a system that automatically generates formatted engineering documents including 3D data converted from 3D applications such as commercial 3D CAD viewer. The system consists of two major modules. One is U3D conversion module and the other is PDF conversion module. U3D conversion module extracts geometry, view data, assembly and disassembly information from 3D viewer and converts to U3D format, currently in IDTF text file format. PDF conversion module generates a PDF file and inserts U3D data, various annotation information, and scripts for custom generated operations such as assembly and disassembly in the PDF document.