• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.607-617
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• 1999

In this paper, we fabricated dual polarization microstrip array antenna to analyze the performance of polarization diversity of each antennas beamwidth and recommend suitable polarizations diversity antenna under indoor environments. The proposed antennas which have directional beam patterns are small, light and thin. Also they are $1\times4$ array and $4\times4$ array antenna with $70^{\circ}$, $20^{\circ}$ beamwidth, respectively. The center frequency is 1890 MHz, IMT-2000's frequency. We also measured the antennas characteristics of each beamwidth in various waveguide structured corridor and compared then with the case of space diversity using the dipole antenna. The measurement shows that the polarization diversity using directional dual polarization microstrip array antennas has more 1~7 dB diversity gain than the space diversity using the dipole antenna. Therefore, the proposed antennas are expected to be efficiently used for the design of optimal directional beam pattern antenna and diversity system for indoor environments.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.135-142
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• 2015

This study was conducted to evaluate the effect of inclusion of propolis extraction residue in the feed of broilers from 1 to 21 d of age on phagocytic activity of macrophages, cutaneous basophil hypersensitivity response to phytohemagglutinin, antibody production against Newcastle disease, lymphoid organ weight and hematological profile and to determine the optimal level of inclusion. 120 chicks, reared in metabolism cages until 21 days of age, were distributed in a completely randomized design, with five treatments (0%, 1%, 2%, 3%, and 4% of propolis residue) and six replications. The relative weight of thymus and monocyte percentage were affected by propolis residue, with a quadratic response (p<0.05) and lowest values estimated at 2.38% and 2.49%, respectively. Changes in relative weight of cloacal bursa and spleen, percentage of lymphocyte, heterophil, basophil, eosinophil, and heterophil:lymphocyte ratio, antibody production against Newcastle disease, phagocytic activity of macrophages and the average number of phagocytosed erythrocytes were not observed. The nitric oxide production with regard to positive control (macrophages+erythrocytes) decreased linearly (p<0.05) with increased doses of propolis residue. The remaining variables of nitric oxide production (negative control - macrophages, and difference between the controls) were not affected by propolis residue. The cutaneous basophil hypersensitivity response to phytohemagglutinin as determined by the increase in interdigital skin thickness exhibited a quadratic response (p<0.05), which predicted a lower reaction response at a dose of 2.60% of propolis residue and highest reaction response after 43.05 hours of phytohemagglutinin injection. The inclusion of 1% to 4% of propolis extraction residue in broiler diets from 1 to 21 days of age was not able to improve the immune parameters, despite the modest changes in the relative weight in thymus, blood monocyte percentage, nitric oxide concentration, and interdigital reaction to phytohemagglutinin.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.71-76
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• 2000

On multimedia teleconferencing system existing a number of participants, face of the participants can beperceived by visual image. However, differentiation of each participant's voice and spaciousness sense are very hard since voice of all participants is processed with one dimensional data. In this paper, we implemented three dimensional audio rendering system using the HRTF(Head Related Transfer Function) and distance sense reproduction method and determined the optimal location of the participants for teleconferencing system. In the results of the listening test using elevation and azimuth angle, we showed that directional perception of the azimuth angles were better than that of the elevation angles. Specially, we showed that participant location using the HRTFS of the azimuth angle 10" , 90" , 270" and350" was efficient in teleconferencing system existing four participants. We also proposed that distance cue was used for enhancement of the reality and location of many participants more than five.ipants more than five.

• Journal of Ginseng Research
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• v.31 no.3
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• pp.159-174
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• 2007

Pharmacology of Korean Red ginseng gives us unique possibility to develop new class of antiepileptic drugs today and to improve one's biological activity. The chemical structures of ginsenosides (GS) have some principal differences from well-known antiepileptic new generation drugs. The antiepileptic effect of GS was also demonstrated in all models of epilepsy in rats (young and adult), which have studied, in all models of epilepsy including status epilepticus (SE), induced by lithium - pilocarpine. In our experiments in rats new evidences on protective effects were exerted as a result of premedication by GS. Pre-treatment of several GS could induce decrease of the seizures severity and brain structural damage (by MRI), neuronal degeneration in hippocampus. Wave nature of severity of motor seizures during convulsive SE was observed during lithium-pilocarpine model of SE in rats (the first increase of seizures was 30 min after the beginning of SE and the second - 90 min after. The efficacy of treatment on SE by ginsenoside as expected was observed after no less 3 weeks by daily GS i.p. administration. It is blocked SE or significantly decrease the severity of seizures during SE. The implication of presented data is that combination of ginsenosides from Korean Red ginseng and ginseng cell culture Dan25 that could be applied for prevention of epileptical status development. However, a development of optimal ratio of different ginsenosides $(Rb_1$ Rc, Rg, Rf,) should consummate in the new antiepileptic drug development.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2816-2822
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• 2014

In this paper, a wideband loop antenna for UWB applications is studied. The structure of the proposed wideband loop antenna is a circular loop antenna with appended circular sectors to obtain an ultra-wideband characteristic. The circular sectors are used instead of conventional triangular sectors to match with the 50 ohm feed line. Optimal design parameters are obtained by analyzing the effects of the gap between the circular sectors and the radius of the circular loop on the input reflection coefficient and gain characteristics. The optimized wideband loop antenna is fabricated on an FR4 substrate with a dimension of 41 mm by 41 mm. Experiment results show that the proposed antenna has a frequency band of 3.1-11.0 GHz for a VSWR < 2.25, which assures the operation in the UWB band. Measured gain ranges 1.3-5.3 dBi in the UWB band.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.3
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• pp.135-144
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• 2004

In this paper, we propose competitive fuzzy polynomial neurons-based advanced Self-Organizing Neural Networks(SONN) architecture for optimal model identification and discuss a comprehensive design methodology supporting its development. The proposed SONN dwells on the ideas of fuzzy rule-based computing and neural networks. And it consists of layers with activation nodes based on fuzzy inference rules and regression polynomial. Each activation node is presented as Fuzzy Polynomial Neuron(FPN) which includes either the simplified or regression polynomial fuzzy inference rules. As the form of the conclusion part of the rules, especially the regression polynomial uses several types of high-order polynomials such as linear, quadratic, and modified quadratic. As the premise part of the rules, both triangular and Gaussian-like membership (unction are studied and the number of the premise input variables used in the rules depends on that of the inputs of its node in each layer. We introduce two kinds of SONN architectures, that is, the basic and modified one with both the generic and the advanced type. Here the basic and modified architecture depend on the number of input variables and the order of polynomial in each layer. The number of the layers and the nodes in each layer of the SONN are not predetermined, unlike in the case of the popular multi-layer perceptron structure, but these are generated in a dynamic way. The superiority and effectiveness of the Proposed SONN architecture is demonstrated through two representative numerical examples.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.29-31
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• 2009

Optimal efficiency control of synchronous reluctance motor(SynRM) is very important in the sense of energy saving and conservation of natural environment because the efficiency of the SynRM is generally lower than that of other types of AC motors. This paper is proposed an efficiency optimization control for the SynRM which minimizes the copper and iron losses. The design of the speed controller based on fuzzy-neural networks (FN)-PI controller that is implemented using fuzzy control and neural networks. There exists a variety of combinations of d and q-axis current which provide a specific motor torque. The objective of the efficiency optimization control is to seek a combination of d and q-axis current components, which provides minimum losses at a certain operating point in steady state. It is shown that the current components which directly govern the torque production have been very well regulated by the efficiency optimization control scheme. The proposed algorithm allows the electromagnetic losses In variable speed and torque drives to be reduced while keeping good torque control dynamics. The control performance of the proposed controller is evaluated by analysis for various operating conditions. Analysis results are presented to show the validity of the proposed algorithm.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.344-352
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• 2020

Covertness and performance are very important design goals in the underwater communications. To satisfy both of them, we proposed efficient underwater communication model which combined multiband and direct sequence spread spectrum method in order to improve performance and covertness simultaneously. Turbo coding method with 1/3 coding rates is used for channel coding algorithm, and turbo equalization method which iterately exchange probabilistic information between equalizer and decoder is used for receiver side. After optimal threshold value was set in Rake processing, this paper analyzed the performance by varying the number of chips were 8, 16, 32 and the number of bands were from 1 to 4. Through the simulation results, we confirmed that the performance improvement was obtained by increasing the number of bands and chips. 2~3 dB of performance gain was obtained when the number of chips were increased in same number of bands.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2696-2707
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• 2021

The purpose of this study is to investigate the efficiency of various structural modeling schemes for evaluating seismic performances and fragility of the reactor containment building (RCB) structure in the advanced power reactor 1400 (APR1400) nuclear power plant (NPP). Four structural modeling schemes, i.e. lumped-mass stick model (LMSM), solid-based finite element model (Solid FEM), multi-layer shell model (MLSM), and beam-truss model (BTM), are developed to simulate the seismic behaviors of the containment structure. A full three-dimensional finite element model (full 3D FEM) is additionally constructed to verify the previous numerical models. A set of input ground motions with response spectra matching to the US NRC 1.60 design spectrum is generated to perform linear and nonlinear time-history analyses. Floor response spectra (FRS) and floor displacements are obtained at the different elevations of the structure since they are critical outputs for evaluating the seismic vulnerability of RCB and secondary components. The results show that the difference in seismic responses between linear and nonlinear analyses gets larger as an earthquake intensity increases. It is observed that the linear analysis underestimates floor displacements while it overestimates floor accelerations. Moreover, a systematic assessment of the capability and efficiency of each structural model is presented thoroughly. MLSM can be an alternative approach to a full 3D FEM, which is complicated in modeling and extremely time-consuming in dynamic analyses. Specifically, BTM is recommended as the optimal model for evaluating the nonlinear seismic performance of NPP structures. Thereafter, linear and nonlinear BTM are employed in a series of time-history analyses to develop fragility curves of RCB for different damage states. It is shown that the linear analysis underestimates the probability of damage of RCB at a given earthquake intensity when compared to the nonlinear analysis. The nonlinear analysis approach is highly suggested for assessing the vulnerability of NPP structures.

• Advances in Computational Design
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• v.4 no.2
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• pp.119-139
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• 2019

Planning and management building projects should tackle the coordination of works and the management of limited spaces, traffic and supplies. Activities cannot be performed without the resources available and resources cannot be used beyond the capacity of workplaces. Otherwise, workspace congestion will negatively affect the flow of works. Better on-site management allows for substantial productivity improvements and cost savings. The procurement system should be able to manage a wider variety of materials and products of the required quality in order to have less stock, in less time, using less space, with less investment and avoiding multiple storage stations. The objective of this paper is to demonstrate the advantages of using the Chronographic modeling, by combining spatiotemporal technical scheduling with the 4D simulations, the Last Planner System and the Takt-time when modeling the construction of building projects. This paper work toward the aforementioned goal by examining the impact that material flow has on site occupancy. The proposed spatiotemporal model promotes efficient site use, defines optimal site-occupancy and workforce-rotation rates, minimizes intermediate stocks, and ensures a suitable procurement process. This paper study the material flow on the site and consider horizontal and vertical paths, traffic flows and appropriate means of transportation to ensure fluidity and safety. This paper contributes to the existing body of knowledge by linking execution and supply to the spatial and temporal aspects. The methodology compare the performance and procurement processes for the proposed Chronographic model with the Gantt-Precedence diagram. Two examples are presented to demonstrate the benefits of the proposed model and to validate the related concepts. This validation is designed to test the model's graphical ability to simulate construction and procurement.