• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.746-755
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• 2014

In this paper, we propose the structure of a dual polarized system for a wireless communication. The proposed dual polarized antenna is formed by one vertical antenna and two horizontal antennas that are orthogonal to each other. Vertical and horizontal polarized antennas transmit different signals, but two orthogonal horizontal polarized antennas transmit the same data signals. So, the signals of the proposed dual polarized system construct two dual-polarization planes. And, only one dual-polarization plane with a large signal power is selected at the side of a receiver. The simulation results show that the proposed dual polarized system could obtain a higher capacity compared to an ordinary $2{\times}2$ MIMO (Multi-input Multi-output) system.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.19-24
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• 2015

The economic efficiency for fishery products can be related to their freshness and the quality. In order to freshly storage the product, freezing equipment system is necessary for fishing vessels. For this purpose, the horizontal plate freezer (HPF) is mostly used. In this research, our major objective is to improve the freezing performance of the HPF. Therefore, it is important to analyse the relationship between the shape of channels and the cooling temperature of the HPF. In order to save calculation time while checking the trend analysis between shape and performance, we used scaled models, and evaluate the cooling temperature of full scale model based on trend analysis results. The produced HPF in domestic was used, and the same operating conditions are considered. Based on this paper, the future research will be a comparison and verification through the experiments.

• Nuclear Engineering and Technology
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• v.21 no.2
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• pp.123-133
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• 1989

The pressure drops through contractions in horizontal single and two-phase flow were investigated. A total of 167 measurements were made for four different entrance shapes to study the effects of the entrance shape on the pressure drop through a contraction in horizontal single and two-phase flow. From this data, pressure drops were calculated and compared with the pressure drops predicted by analytical models for single and two-phase flow. For single phase How the agreement between the data and predictions is within $\pm$25%, whereas for two-phase flow Hoopes model, which gives a better agreement than the homogeneous model, underpredicts the data as much as 45% In addition, the effects of void fraction and liquid phase mass velocity on the pressure drop through the sudden How channel contraction were investigated for two-phase flow.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.214-221
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• 2012

Recently, the biochip which is a prime representation of NT, IT, BT, as an example of convergence technology, has been frequently mentioned. With the recent rapid advance in biotechnology, these compact devices, such as lab-on-a-chip or u-TAS, have been developed, and more research is needed. These compact devices typically use the micro-channel in order to shed or detach and mix a variety of materials. Specially, in micro-fluidic systems, a mixer is necessary to produce a mixture because only laminar flow occurs at a low-Reynolds number. To solve this problem, HVM a micromixer that induces a horizontal and vertical multi-mixing flow motion, is proposed. The mixing performance was analyzed and verified by optimizing the shape through the CFD analysis and evaluating the structural analysis and the soundness with material properties that are obtained through the basic experiment.

• Journal of Sensor Science and Technology
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• v.29 no.3
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• pp.172-179
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• 2020

We studied an integrated-optic biosensor configuration that operates at a wavelength of 0.63 ㎛ based on the evanescent-wave and two horizontal mode power coupling of Si₃N₄ rib-optical waveguides formed on a Si/SiO₂/Si₃N₄/SiO₂ multilayer thin films. The sensor consists of a single-mode input waveguide, followed by a two-mode section which acts as the sensing region, and a Y-branch output for separating the two output waveguides. The coupling between the two propagating modes in the sensing region produces a periodically repeated optical power exchanges along the propagation. A light power was steered from one output channel to the other due to the change in the cladding layer (bio-material) refractive index, which affected the effective refractive index (phase-shift) of two modes through evanescent-wave. Waveguide analyses based on the rib optical waveguide dimensions were performed using various numerical computational software. Sensitivity values of 12~23 and 65~165 au/RIU, respectively for the width and length of 4 ㎛, and 3841.46 and 26250 ㎛ of the two-mode region corresponding to the refractive index range 1.36~1.43 and 1.398~1.41, respectively, were obtained.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2
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• pp.68-77
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• 2005

The purpose of a spatial audio system is to give a listener an impression as if he were present in a recorded environment when its sound is reproduced. For this purpose a dummy head microphone is generally used. Because of its human-like shape, dummy head microphone can reproduce spatial images through headphone reproduction. However, its shape and size are restriction to public use and it is difficult to convert the output signal of dummy head microphone into a multi-channel signal for multi-channel environment. So, in this paper, we propose a multi-channel 3D microphone technology. The multi-channel 3D microphone acquire a spatial audio using five microphones around a horizontal plane of a rigid sphere and through post processing, it can reproduce various reproduction signals for headphone, stereo, stereo dipole, 4ch and 5ch reproduction environments. Because of complex computation, we implemented H/W based post processing system. To verily the Performance of the multi-channel 3D microphone, localization experiments were Performed. The result shows that a front/back confusion, which is the one of common limitations of conventional dummy head technology, can be reduced dramatically.

• Journal of Korea Water Resources Association
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• v.38 no.8 s.157
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• pp.675-689
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• 2005

In this paper, it was analyzed the variation of hydraulic characteristics through changing discharge at main channel and lateral channel and state of hydraulic structure at the natural channel junction by experiment. The experimental area is chosen at the channel junction of Nam-Han river and Pyeongchang river. The scale of the experiment is 1/200 in horizontal, and 1/66.7 in vortical, so the distoration rate is 3. From the experiment, the reduction effect of the water level is $12\%$ in the case of removing intank dam, and $5\%$ at the hydro-electronic dam removing case. Furthermore, in the case of two hydraulic structures removing, the reduction effect of water level is $18\%$ at the channel junction. Also, the stagnation zone, which is cased diminution of the channel at the junction, is decreasing through removing the structures.

• The KSFM Journal of Fluid Machinery
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• v.11 no.6
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• pp.38-45
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• 2008

Development of high efficiency turbine with good performance is one of the main topics in the field of developing wave energy converter. For the development and improvement of the turbine performance, the effect of wave condition on the turbine performance should be considered in detail. Also, water depth is an important factor because incident wave power to the turbine is considerably influenced by the wave particle amplitude of motion and the amplitude is closely related with the water depth. Therefore, in this study, the effect of water depth on the performance of a direct drive turbine(DDT) for wave energy converter is investigated using the DDT which is installed in two types of wave channel. The experimental results show that the DDT captures more wave energy under the condition of relatively shallow water depth. When the water depth is shallow, the horizontal water particle amplitude of motion becomes wider and thus, the water power toward the turbine becomes larger.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.5
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• pp.31-35
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• 2011

In this paper, the miniaturized FM transmitter with dual-frequency is developed, and tested in the field. In this system two frequencies 88.1 MHz and 88.3 MHz is used. The transmitter is designed with 2.6 cm^3 system size, horizontal, vertical, height respectively. The operating voltage is 3.7 V and used the built-in storage battery in order to minimize. The system can use continuously during 7 hour with once charging. The channel separation ability is 40 dB. Consequently, this system is used conveniently with short distance information transmitter system at the industry field.

• Progress in Superconductivity
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• v.14 no.2
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• pp.82-86
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• 2012

A sensitive eight-channel high-Tc Superconducting Interference Device (SQUID) detection system for magnetic contaminant in a lithium ion battery anode was developed. Finding ultra-small metallic foreign matter is an important issue for a manufacturer because metallic contaminants carry the risk of an internal short. When contamination occurs, the manufacturer of the product suffers a great loss from recalling the tainted product. Metallic particles with outer dimensions smaller than 100 microns cannot be detected using a conventional X-ray imaging system. Therefore, a highly sensitive detection system for small foreign matter is required. We have already developed a detection system based on a single-channel SQUID gradiometer and horizontal magnetization. For practical use, the detection width of the system should be increased to at least 65 mm by employing multiple sensors. In this paper, we present an 8-ch high-Tc SQUID roll-to-roll system for inspecting a lithium-ion battery anode with a width of 65 mm. A special microscopic type of a cryostat was developed upon which eight SQUID gradiometers were mounted. As a result, small iron particles of 35 microns on a real lithium-ion battery anode with a width of 70 mm were successfully detected. This system is practical for the detection of contaminants in a lithium ion battery anode sheet.