• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.1
• /
• pp.62-67
• /
• 2003

This paper is concerned with the design of the beam forming module that is a key unit of the active phased array antenna(APAA) system for mobile satellite communications. This module includes two blocks for main signal and tracking signal. Main signal block has the role of transmitting input signal from phased array antenna to tracking signal block. And, tracking signal block executes main roles, beam forming of tracking signal and electronic beam control. The several electrical performances of this module, phase characteristics and linear gain, etc., agreed with specifications needed fur APAA, and for more clear verification of the performances, the satellite communication test of the APAA including the modules was accomplished in the outdoors.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.49-52
• /
• 2008

The present study conducts a series of experiments to develop a novel air supplying module for a micro fuel cell using piezoelectric linear actuator. An intermittently and operating air breathing module with reciprocating motion of the linear actuator has been suggested in the present study. A test bench for a micro fuel cell system has been constructed to estimate performance of the active fuel cell system using the air supplying module. With the stroke and operating duty as main control parameters, the optimal operating method of the air supplying module has been discussed.

• Transactions of Materials Processing
• /
• v.12 no.6
• /
• pp.550-557
• /
• 2003

In this study, a web-based system was developed by utilizing finite element method and virtual system designed using Virtual Reality Modeling Language (VRML). The simulation program for axi-symetric sheet forming is developed using finite flement method. The developed system consists of two modules, client module and server module. The client module was developed by using Active-X control. The input data for FEM calculation is transferred to the server module by using communication protocol. Then sever module performs several successive processes: input data generation, forming simulation, conversion of results to VRML format. After that, the results from the simulation can be visualized on the web browser in client computer. Besides, client module offers the capability to control and navigate on virtual forming machine and calculated result. By using this system simulation result can be investigated more realistically in virtual environment including forming machine.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2020.11a
• /
• pp.65-68
• /
• 2020

자체 제작한 프로그램인 USB 보안 모듈과 Active Directory를 활용하여 서버에서 다수의 클라이언트를 관리할 수 있는 인프라를 구축한다. USB 보안 모듈과 기존 소극적인 보안 정책으로 인해 개인 또는 내부망으로 사용하고 있는 Active Directory의 보안 정책을 결합하여 극단적이고 폐쇄적인 강력한 보안 기능을 가능케 하며 그 효용성을 제안 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.317-318
• /
• 2013

• Korean Journal of Cognitive Science
• /
• v.14 no.3
• /
• pp.13-21
• /
• 2003

This study presents a design of Teachable Agent(TA) and its theoretical background. TA is an intelligent agent to which students as tutors teach, pose questions, and provide feedbacks using a concept map. TA consists of four independent Modules, Teach Module, Q&A Module, Test Module, and Resource Module. In Teach Module, students teach TA by constructing concept map. In Q&A Module, both students and TA ask questions and answer questions each other through an interactive window. To assess TA's knowledge and provide feedback to students, Test Module consists of a set of predetermined questions which TA should pass. From Resource Module, students can search and look up important information to teach, ask questions, and provide feedbacks whenever they want. It is expected that TA should provide student tutors with an active role in learning and positive attitude toward the subject matter by enhancing their cognition as well as motivation.

• ETRI Journal
• /
• v.35 no.3
• /
• pp.378-385
• /
• 2013

An S-band multifunction chip with a simple interface for an active phased array base station antenna for next-generation mobile communications is designed and fabricated using commercial 0.5-${\mu}m$ GaAs pHEMT technology. To reduce the cost of the module assembly and to reduce the number of chip interfaces for a compact transmit/receive module, a digital serial-to-parallel converter and an active bias circuit are integrated into the designed chip. The chip can be controlled and driven using only five interfaces. With 6-bit phase shifting and 6-bit attenuation, it provides a wideband performance employing a shunt-feedback technique for amplifiers. With a compact size of 16 $mm^2$ ($4mm{\times}4mm$), the proposed chip exhibits a gain of 26 dB, a P1dB of 12 dBm, and a noise figure of 3.5 dB over a wide frequency range of 1.8 GHz to 3.2 GHz.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.2
• /
• pp.121-129
• /
• 2000

The robotic automation in NonDestructive Testing(NDT) is a promising field of research and it helps to expand the applications of NDT enormously. Especially, in the case of pipelines which are widely used in various industrial facilities, it is required to secure adequate ways of inspection in the usual maintenance activitites. In this paper, we present a robot system for inpipe inspection of underground urban gas pipelines. The robot is configured as an articulated structure like a snake with a tether cable. Two active driving vehicles are located in front and rear of the system, respectively and passive modules such as a NonDestructive Testing module and a control module are chained between the active vehicles. The proposed system has outstanding mobility by employing a new steering mechanism called Double Active Universal Joint, which makes it possible to cope with complicated configurations of underground pipelines. Characteristic features of the system are described and the construction of the system is briefly outlined.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.149-150
• /
• 2008

In this paper, we propose a new RF education system using real module that engineer apply at actual companies and laboratories. The proposed system provides beginner and college students with a real effect of RF hardware education. The Optimized RF education system we present is made up of a real passive module, active module, mobile communication module, DSP based system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.10
• /
• pp.1050-1060
• /
• 2009

In this paper, a X-Band T/R-module for SAR(Synthetic Aperture Radar) systems based on active phased array antennas is designed and fabricated. The T/R modules have a and width of more than 800 MHz centered at X-Band and support dual, switched polarizations. The output power of the module is 7 watts over a wide bandwidth. The noise figure is as low as 3.9 dB. Phase and amplitude are controlled by a 6-bit phase shifter and a 6-bit digital attenuator, respectively. Further the fabricated T/R module has est and calibration port with directional coupler and power divider. Highly integrated T/R module is achieved by using LTCC(Low Temperature Co-fired Ceramic) multiple layer substrate. RMS gain error is less than 0.8 dB max. in Rx mode, and RMS phase error is less than $4^{\circ}$ max. in Rx/Tx phase under all operating frequency band, or the T/R module meet the required electrical performance m test. This structure an be applied to active phase array SAR Antennas.