• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1897-1904
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• 2002

Monotonic torsional and pure torsional low cycle fatigue(LCF) test with artificial degradation were performed on duplex stainless steel(CF8M). CF8M is used in pipes and valves in nuclear reactor coolant system. It was aged at 430$^{\circ}C$ for 3600hrs. Through the monotonic and LCF test, it is found that mechanical properties(i.e., yield strength, strain hardening exponent, strength coefficient etc.) increase and fatigue life(N$\sub$f/) decreases with degradation of material. The relationship between shear strain amplitude(${\gamma}$$\sub$a/)and N$\sub$f/ was proposed.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.465-468
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• 2000

본 논문에서는 인식코드를 전송할 수 있는 modulator 뿐만 아니라 Reader system으로부터 코드 전송제어 명령어를 수신할 수 있고 향후 EEPROM과 더불어 인식코드를 수정할 수 있는 RFID (Radio Frequency IDentification) Transponder 칩 설계에 관한 내용을 다룬다. RFID칩은 배터리를 사용하지 않고 명령어와 함께 형성되는 Field로부터 전원을 생성하고 동시에 코드를 제공하는 Full-Duplex 구조로 설계하였다. Transponder IC는 power-generation 회로, clock generation 회로, digital block, modulator, overvoltage protection 회로로 구성된다. 설계된 칩은 저전력 회로를 적용하여 원거리 transponder칩을 구현할 수 있도록 하였다. 설계된 회로는 $0.6{\mu}m$ 현대 CMOS 공정으로 레이아웃 하였으며 제작중에 있다.

• ETRI Journal
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• v.40 no.5
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• pp.582-591
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• 2018

In this paper, we present a performance analysis of large-scale multi-input multi-output (MIMO) systems for wireless backhaul networks. We focus on fully connected N nodes in a wireless meshed and multi-hop network topology. We also consider a large number of antennas at both the receiver and transmitter. We investigate the transmission schemes to support fully connected N nodes for half-duplex and full-duplex transmission, analyze the achievable ergodic sum rate among N nodes, and propose a closed-form expression of the achievable ergodic sum rate for each scheme. Furthermore, we present numerical evaluation results and compare the resuts with closed-form expressions.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.507-508
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• 2006

In this communication the development of a new metal injection moulding (MIM) system for duplex stainless steels is presented. The metal powders were prepared by premixing 316L and 430L stainless steels gas atomised powders in a ratio of 50:50. The binder used to prepare the feedstock was composed by HDPE and paraffin wax. Torque measurements of the mixture indicated that the maximum amount of metal was 68 vol%. The polymeric part was driven off by thermal debinding and the sintering was performed in low vacuum. The final densities were close to the theoretical ones.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.133-139
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• 2008

Cyber university can easily study the lecture only press the couple of mouse click or keyboard button anywhere and anytime, if you have a computer. Many people believe that virtual university can save time and improve learning. To check How many students learn which selected some of the virtual university courses, instructor must know how to the understanding students and find out their difficult problems. Without checking this condition, it will be a very difficult and boring virtual university course. In this paper, we introduce the intelligent learning system. It has a full duplex direction that teaches understanding students and not understanding students. The computer simulation results confirmed that a full duplex virtual learning system has been proven to be much more efficient than one way direction which unfortunately does not consider to understanding problems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.46-52
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• 2004

A design methodology of the redundancy management for a duplex FBW flight control system is introduced. A statistical analysis is applied to determine two design parameters in CCM(Cross Channel Monitor), threshold and persistence count. An analytic redundancy, which is implemented using a Kalman filtering algorithm is considered. The application of an analytic redundancy to the FCS design of the smart UAV has several advantages of increasing the aircraft's survivability and breaking the tie-condition for a duplex FCS. All the redundancy management algorithms are verified through the numeric simulation for the flight dynamics of the XV-15 tilt rotor.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4223-4239
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• 2016

In this paper, we consider an amplify-and-forward (AF) full-duplex relay network (FDRN) using simultaneous wireless information and power transfer, where a battery-free relay node harvests energy from the received radio frequency (RF) signals from a source node and uses the harvested energy to forward the source information to destination node. The time-switching relaying (TSR) protocol is studied, with the assumption that the channel state information (CSI) at the relay node is imperfect. We deliver a rigorous analysis of the outage probability of the proposed system. Based on the outage probability expressions, the optimal time switching factor are obtained via the numerical search method. The simulation and numerical results provide practical insights into the effect of various system parameters, such as the time switching factor, the noise power, the energy harvesting efficiency, and the channel estimation error on the performance of this network. It is also observed that for the imperfect CSI case, the proposed scheme still can provide acceptable outage performance given that the channel estimation error is bounded in a permissible interval.

• Journal of the Korea Computer Industry Society
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• v.5 no.4
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• pp.435-442
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• 2004

Virtual university can easily study the lecture only press the couple of mouse click or keyboard button anywhere and anytime, if you have a computer. Many people believe that virtual university, can save time and improve learning. To check how many students learn which selected some of virtual university courses, instructor must knows how to the understanding students and find out their difficult problems. Without checking this condition, it will be a very difficult and boring virtual university course. In this paper, we introduce the intelligent learning system. It has a full duplex direction that teachs understanding students and not understanding student. The computer simulation results confirms that full duplex virtual learning system has been proven to be much more efficient than one way direction which unfortunately does not consider to understanding problems.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.68-74
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• 2015

Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.

• Journal of Power System Engineering
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• v.18 no.2
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• pp.70-76
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• 2014

A specimen of weld metal was prepared by GTA welding with weld wire of super duplex stainless steel. Aging treatment was conducted for the sample at the temperature range of 700 to $900^{\circ}C$ for 5 to 300 minutes. The effect of aging temperature and time to pitting corrosion of weld metal has been investigated and the results were derived as follows. The volume fraction of ${\sigma}$ phase tends to increase with an increase of aging temperature and time. Pitting potential Ep representing pitting corrosion was found to tend to decrease with an increase of aging time at 700 to $900^{\circ}C$. And most of the pits formed near the ${\sigma}$-phase in the ferrite and seemed to propagated to austenite.