• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.788-794
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• 2005

In this paper, we focus on the potential of dual polarized antennas in mobile system. thus, this paper designs exact dual polarized channel with Spatial Channel Model (SCM) and investigates the performance for certain environment. Using proposed the channel model; we know estimates of the channel capacity as a function of cross polarization discrimination (XPD) and spatial fading correlation. It is important that the MIMO channel matrix consists of Kronecker product dividable spatial and polarized channel. Through the channel characteristics, we propose an algorithm for the adaptation of transmit antenna configuration to time varying propagation environments. The optimal active transmit antenna subset is determined with equal power allocated to the active transmit antennas, assuming no feedback information on types of the selected antennas. We first consider a heuristic decision strategy in which the optimal active transmit antenna subset and its system capacity are determined such that the transmission data rate is maximized among all possible types. This paper then proposes singular values decision procedure consisting of Kronecker product with spatial and polarize channel. This method of singular value decision, which the first channel environments is determined using singular values of spatial channel part which is made of environment parameters and distance between antennas. level of correlation. Then we will select antenna which have various polarization type. After spatial channel structure is decided, we contact polarization types which have considerable cases It is note that the proposed algorithms and analysis of dual polarized channel using SCM (Spatial Channel Model) optimize channel capacity and reduce the number of transmit antenna selection compare to heuristic method which has considerable 100 cases.

• Journal of Technology Innovation
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• v.14 no.3
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• pp.209-235
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• 2006

Since the end of the cold war, technical tie-up between private corporations and an army in developed countries has increased a lot, and the trend is spreading through developing countries rapidly. To cope with the circumstance actively, the dual use technology program for both private corporations and an army was begun in Korea in 1998. With the program, overlapping investment was resolved and technology transfer was stimulated. And the standardization and information exchange saved considerable national budget and made possible economic profit. Yet, the combination project of 4 ministries and offices showed problems such as loose cooperation and, low industralization record. However, developed countries are out of the mere stage of dual technology development and turn into broad technical tie-up including future prediction, national competitiveness improvement, and the private company's leading participation and they are systemizing them very fast. Korea also set up the national defense reform plan with the blueprint of future military force improvement, budget increase for national defense research, and increased participation of private corporations, and created Defense Acquisition program Administration to support them. The innovation of national defense system brings forward the need to link the private and military innovation. Korea has pursued the fast growth through assimilation, absorption, and improvement of foreign technology. But now, Korea has to focus on self innovation, original technology, parts and material. As this applies to private companies and military equally, it is important to concentrate limited resources for the effective technology cooperation. Considering this, the strategies to activate the dual use technology are program concept and range extension, task-deduction way improvement and future-oriented common task deduction, and promotion system improvement.

• Journal of Family Resource Management and Policy Review
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• v.26 no.1
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• pp.15-26
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• 2022

The first purpose of this paper was to investigate whether wives' income contributions affect the time spent on housework by dual-earner couples. The second purpose was to investigate period interaction effects on the effect of wives' income contributions. For this, Korean Time Use Survey data 2004-2019 was analyzed. The analysis target was dual-earner couple aged 20-59 years. The dependent variable was time spent on housework, and the analysis method was tobit regression. According to the results, there were three findings: First, there was a U-shaped relation between wives' income contributions and wives' housework time. Second, this relationship became stronger as time progressed. Third, although wives' income contributions positively affected husband housework time, husband housework time was actually zero before 2019. These results demonstrated that not economic perspective, but gender perspective, is more useful for understanding dual-earner couples' division of housework.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.158-163
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• 2013

The fusion of the GPS (Global Positioning System) and DR (Dead Reckoning) is widely used for position and latitude estimation of vehicles such as a mobile robot, aerial vehicle and marine vehicle. Among the many types of aerial vehicles, grater focus is given on the quad-rotor and accuracy of the position information is becoming more important. In order to exactly estimate the position information, we propose the fusion method of GPS and Gyroscope sensor using the DEKF (Dual Extended Kalman Filter). The DEKF has an advantage of simultaneously estimating state value and a parameter of dynamical system. It can also be used even if state value is not available. In order to analyze the performance of DEKF, the computer simulation for estimating the position, the velocity and the angle in a circle trajectory of quad-rotor was done. As it can be seen from the simulation results using own proposed DEKF instead of EKF on own fusion method in the navigation of a quad-rotor gave better performance values.

• Journal of electromagnetic engineering and science
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• v.12 no.1
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• pp.26-31
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• 2012

We have proposed a metamaterial lens that enables sub-wavelength focusing, which is shorter than an operating wavelength. Our lens is a two dimensional array of a unit cell consisting of a metallic dual-plate printed on a dielectric substrate. The unique dual-plate structure provides negativeness both in permittivity and permeability, with no help from conventional additional structures, which are normally printed on the opposite of metallic patterns. Therefore, we can focus a source (or an image) in a tiny distance shorter than the free space wavelength (${\lambda}$) at the frequencies of interest. Furthermore, since the proposed geometry does not need separate supplementary structures to acquire negative permittivity or permeability, our lens is much simpler than conventional metamaterial lenses, which is a strong point in practical applications. We have validated sub-wavelength focusing ability in a 6 GHz frequency band through an experiment of near field scanning, which provided the width of about 0.19 ${\lambda}$ at a half maximum of a peak value of an measured image. The width of the focused image through the lens is more than 4 times shorter than that without the lens, which confirms the validity of our design approach.

• Journal of the Korean Society of Visualization
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• v.8 no.4
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• pp.60-65
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• 2010

A focus is given to the breakup behavior of spray droplets issuing from a nonimpinging-type injector. The analysis has been carried out experimentally by means of the dual-mode phase Doppler anemometry (DPDA). Spray characteristic parameters in terms of axial velocity, mean diameter, velocity fluctuation, and span (width of the size distribution) of droplets are measured down the geometric axis of a nozzle orifice and on the plane normal to the spray stream with the injection pressure variations. As the injection pressure increases, the velocity and its fluctuation become higher, whereas the droplet sizes get smaller. It is also shown that the magnitudes of those parameters are smoothed out by dispersion when the droplets move downstream as well as outwardly. The atomization process is significantly influenced by the injection pressure rather than the traveling distance in the experimental condition presented.

• International Journal of Contents
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• v.14 no.1
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• pp.18-27
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• 2018

The objective of this study was to derive approximate closed-form error rates for M-ary burst symbol transmission (MBST) of dual-hop adaptive decode-and-forward (ADF) cooperative relay systems over quasi-static Rayleigh fading channels. Within a burst, there are pilot symbols and data symbols. Pilot symbols are used for channel estimation schemes and each relay node's transmission mode selection schemes. At first, our focus was on ADF relay systems' error-events at relay nodes. Each event's occurrence probability and probability density function (PDF) were then derived. With error-event based approach, we derived a tractable form of PDF for combined signal-to-noise ratio (SNR). Averaged error rates were then derived as approximate expressions for arbitrary link SNR with different modulation orders and numbers of relays. Its accuracy was verified by comparison with simulation results.

• Geomechanics and Engineering
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• v.15 no.5
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• pp.1039-1046
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• 2018

This paper presents a limit analysis of the series of construction stages of shallow tunneling method by investigating their respective safety factors and failure mechanisms. A case study for one particular cross-section of Beijing Subway Line 7 is undertaken, with a focus on the effects of multiple soil layers and construction sequencing of dual tunnels. Results show that using the step-excavation technique can render a higher safety factor for the excavation of a tunnel compared to the entire cross-section being excavated all at once. The failure mechanisms for each different construction stage are discussed and corresponding key locations are suggested to monitor the safety during tunneling. Simultaneous excavation of dual tunnels in the same cross-section should be expressly avoided considering their potential negative interactions. The normal and shear forces as well as bending moment of the primary lining and locking anchor pipe are found to reach their maximum value at Stage 6, before closure of the primary lining. Designing these struts should consider the effects of different construction stages of shallow tunneling method.

• BMB Reports
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• v.45 no.2
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• pp.71-78
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• 2012

Bdellovibrio bacteriovorus is a predatory bacterium which attacks and consumes other bacterial strains, including the well known pathogens E. coli O157 : H7, Salmonella typhimurium and Helicobacter pylori. This remarkable activity has been the focus of research for nearly five decades, with exciting practical applications to medical, agriculture and farming practices recently being published. This article reviews many of the exciting steps research into this bacterium, and similar bacteria, has taken, focusing primarily on their use as both an antibiotic to remove harmful and pathogenic bacteria and as a probiotic to help curb and control the bacterial populations within the intestinal tract. Owing to the unique and dual nature of this bacterium, this review proposes the use of "amphibiotic" to describe these bacteria and their activities.

• Molecules and Cells
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• v.22 no.2
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• pp.127-132
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• 2006

In the post genome project era, it is well established that the human genome contains a smaller number of genes than expected. The complexity found in higher organisms can be explained if proteins are multifunctional. Indeed, recent studies are continuing to reveal proteins that are capable of a broad repertoire of functions. A good paradigm for multifunctionality can be found in the amino-acyl tRNA synthetases (aaRSs), an ancient conserved family of proteins. This unique family, which is comprised of 20 different enzymes, is well known for its participation in protein synthesis. Several studies have described numerous examples of these "housekeeping" proteins taking part in extensive critical cellular activities. In this review, we focus on a member of that family, lysyl-tRNA synthetase (LysRS), which has been shown to have a dual functionality. In addition to its contribution to the translation process, LysRS also takes part in the regulation of MITF and USF2 target genes. This phenomenon was first described in mast cells.