• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2006년도 하계종합학술대회
• /
• pp.659-660
• /
• 2006

The low crosstalk row-decoder is studied for PoRAM applications. Because polymer-based memories can be more densely integrated than established silicon-based ones, PoRAM is highly sensitive for the crosstalk problem. To overcome the problem and to suggest the suitable decoder for PoRAM, this paper shows the comparison of the row-path characteristics for both the 2-stage dynamic logic decoder and the 2-stage static logic decoder. Moreover, to suppress the Glitch effect which is observed by using the static logic decoder, the Master-Slave(M/S) D-Flip/Flop(D-F/F) is applied as a deglitch. Finally, the improved output result of the 2-stage static logic decoder with the M/S D-F/F is shown..

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제8권1호
• /
• pp.39-59
• /
• 2008

The performance of weapon system, based on the acceleration of advanced scientific technology, has been reinforced to the state of precision, complexion and multi-function. People have given great interest for a long time on its development, acquisition cost and enormous expense of operation/support. Under this environmental situation, this research paper proposes two kinds of implementation that can improve the RAM(Reliability, Availability, Maintainability) on weapon system. The first section is to understand all of the actual states on its reliability, in the acquisition process and to make the improvement for RAM at the milestones on the acquisition steps. The next section is to establish a defense RAM center, which will be closely cooperated with acquisition organization such as Ministry of Defense, DAPA(Defense Acquisition Program Administration), DTaQ(Defense agency for Technology and Quality) and ADD(Agency for Defense Development), etc. and to conclusively improve the RAM of weapon system in South Korea.

• 항공우주시스템공학회지
• /
• 제4권3호
• /
• pp.24-28
• /
• 2010

The purpose of this study is to define available microwave absorbing structure for aircraft from in the X-band(8.2~12.4GHz) frequencies. The electromagnetic wave absorption or shielding techniques is an important issue not only for military purpose but also for commercial purposes. Aircraft Radar Absorbing Structure(RAS) is absorbed or scattered propagation waves from the enemy radar. There are absorbing technologies at shaping design techniques and using Radar Absorbing Materials(RAM). RAM is more important because shaping design can't include perfect radar absorbing performance. In this study, based on material properties was introduced RAM and to analyze the each characteristics. Finally, we comparison appropriate RAM for aircraft.

• 대한임베디드공학회논문지
• /
• 제6권1호
• /
• pp.32-40
• /
• 2011

For a NAND booting based embedded system, an application program on the NAND flash memory is downloaded to the RAM when the system is booted. In this case, the application program exists in both the RAM and the NAND flash so the RAM usage is increased. In this paper, we suggested the demand paging technique for the decreasing of the RAM usage for OS-less NAND booting based embedded systems. As a result of a benchmark test, 40~80% of the code memory usage was reduced with below 5% of execution time delay.

• 천문학회보
• /
• 제45권1호
• /
• pp.65.1-65.1
• /
• 2020

We present high-resolution, high-sensitivity continuum data of NGC 4522 observed at 3 cm (X-band) and 10 cm (S-band) in full polarization mode using the JVLA. This observation has 2 - 4 times better spatial resolution and 2 - 5 times better sensitivity compared to previous continuum observations. NGC 4522 is a Virgo spiral galaxy undergoing active ram pressure stripping. This galaxy is particularly well known for the CO emission detected outside its stellar disk, some of which coincides with the extraplanar HI gas and Halpha patches. The major goal of our JVLA observation is to leverage our understanding of the influence of the ram pressure on the general ISM field and multi-phase medium. By combining our new deep radio continuum data and previous observations, we will investigate how the B-field properties can be affected by the ram pressure, and what roles the B-field plays in the stripping process of the multi-phased ISM and in the star formation activity when the ram pressure is present.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 1999년도 추계 학술대회논문집
• /
• pp.77-84
• /
• 1999

Numerical design optimization techniques are implemented for the improvement of the ram accelerator performance. The design object is to find the minimum ram tube length required to accelerate projectile from initial velocity $V_0$ to target velocity $V_e$. The premixture is composed of $H_2,\;O_2,\;N_2$ and the mole numbers of these species are selected as design variables. The objective function and the constraints are linearized during the optimization process and gradient-based Simplex method and SLP(Sequential Linear Programming) have been employed. With the assumption of two dimensional inviscid flow for internal flow field, the analyses of the nonequilibrium chemical reactions for 8 steps 7 species lave been performed. To determined the tube length, ram tube internal flow field is assumed to be in a quasi-steady state and the flow velocity is divided into several subregions with equal interval. Hence the thrust coefficients and accelerations for corresponding subregions are obtained and integrated for the whole velocity region. With the proposed design optimization techniques, the total ram tube length had been reduced $19\%$ within 7 design iterations. This optimization procedure can be directly applied to the multi-stage, multi-premixture ram accelerator design optimization problems.

• 한국전기전자재료학회논문지
• /
• 제27권2호
• /
• pp.81-84
• /
• 2014

The bipolar resistive switching characteristics of resistive random access memory (ReRAM) based on $HfO_2$ thin films have been demonstrated by using Ag/$HfO_2$/Pt structured ReRAM device. MIcrowave irradiation (MWI) treatment at low temperature was employed in device fabrication with $HfO_2$ thin films as a transition layer. Compared to the as-deposited Ag/$HfO_2$/Pt device, highly improved uniformity characteristics of resistance values and operating voltages were obtained from the MWI treatment Ag/$HfO_2$/Pt ReRAM device. In addition, a stable DC endurance (> 100 cycles) and a high data retention (> $10^4$ sec) were achieved.

• 한국전기전자재료학회논문지
• /
• 제29권3호
• /
• pp.135-140
• /
• 2016

In this study, we developed the solution-processed PMMA-$HfO_x$ hybrid ReRAM devices to overcome the respective drawbacks of organic and inorganic materials. The performances of PMMA-$HfO_x$ hybrid ReRAM were compared to those of PMMA- and $HfO_x$-based ReRAMs. Bipolar resistive switching behavior was observed from these ReRAMs. The PMMA-$HfO_x$ hybrid ReRAMs showed a larger operation voltage margin and memory window than PMMA-based and $HfO_x$-based ReRAMs. The reliability and electrical instability of ReRAMs were remarkably improved by blending the $HfO_x$ into PMMA. An Ohmic conduction path was commonly generated in the LRS (low resistance state). In HRS (high resistance state), the PMMA-based ReRAM showed SCLC (space charge limited conduction). the PMMA-$HfO_x$ hybrid ReRAM and $HfO_x$-based ReRAM revealed the Pool-Frenkel conduction. As a result of flexibility test, serious defects were generated in $HfO_x$ film deposited on PI (polyimide) substrate. On the other hand, the PMMA and PMMA-$HfO_x$ films showed an excellent flexibility without defect generation.

• 한국전기전자재료학회논문지
• /
• 제27권8호
• /
• pp.491-496
• /
• 2014

The resistive switching characteristics of resistive random access memory (ReRAM) based on amorphous $Ge_{0.5}Se_{0.5}$ thin films have been demonstrated by using Ti/Ag nanocrystals/$Ge_{0.5}Se_{0.5}$/Pt structure. Ag nanocrystals (Ag NCs) were spread on the amorphous $Ge_{0.5}Se_{0.5}$ thin film and they played the role of metal ions source. As a result, comparing the conventional Ag/$Ge_{0.5}Se_{0.5}$/Pt structure, this Ti/Ag NCs/$Ge_{0.5}Se_{0.5}$/Pt ReRAM device exhibits the highly uniform bipolar resistive switching (BRS) characteristics, such as the operating voltages, and the resistance values. At the same time, a stable DC endurance(> 100 cycles), and the excellent data retention (> $10^4$ sec) properties were found from the Ti/Ag NCs/$Ge_{0.5}Se_{0.5}$/Pt structured ReRAM device.

• 시스템엔지니어링학술지
• /
• 제15권1호
• /
• pp.16-24
• /
• 2019

In this study, an improved method of setting the RAM goals for surveillance system using OMS/MP and field operations data of similar systems is suggested and a case study of surveillance system A is given. Newly suggested methods for setting the RAM goals consist of the procedures such as On/Off time analysis of configuration equipment based on OMS/MP, field operations data analysis of similar systems, adjustment of preventive maintenance time, the number of corrective maintenances, and TALDT in wartime, introducing new subsystem to reliability structure of surveillance system, and reflecting expert's opinion. A case study of surveillance system A shows that newly suggested method in this study for setting the RAM goals is reasonably acceptable and practically applicable to other similar systems.