• The Journal of the Acoustical Society of Korea
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• v.16 no.6
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• pp.100-105
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• 1997

To analyze the multipath propagation effects on the source bearing detection of HLA(Horizontal Line Array), the conversion mechanism of the multipath into the bearing is described, and the bearing is estimated from the multipath modeled with typical sound velocity structures of the East and the South Sea of Korea. The erroneous bearing is observed from the beamforming outputs simulated with the modeled multipath, and the erroneous phenomena are analyzed. In case of the East Sea, since the multipath propagation with a high receiving angle occurs due to strong inverse slope of the sound velocity structure, it is possible that the estimated source bearing is different from the real source bearing, and that the number of the source is misrecognized.

• Journal of the Korean Home Economics Association
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• v.46 no.9
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• pp.137-146
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• 2008

This study was conducted in order to spread out lower body 3D scan data of men in their twenties. The aim was to achieve slacks pattern with ease allowance through comparison with existing flat patterns. For conversion of 3D scan data into 20 pattern, reference lines were established by using Rapid Foam in 3D shape analysis software. 2C-AN program and Yuka CAD were used to convert 20 pattern earned with straight posture of 3D scan data into slacks pattern by using Triangle Simplification & Runge-Kutta Method. In order to achieve this we needed to set a line 9cm below the hip line, to array vertex of each block to crease line while maintaining the horizontal line. And then we needed to set ease allowance in back crotch and to set waist circumference or hip circumference ease allowance in side seam of slacks. Results showed that long front crotch length can be achieved if 3D scan data is compared with 20 existing flat pattern. Slacks pattern that raise front crotch by about 1.5cm compared to back crotch and also possess ease allowance in back crotch area are great in appearance evaluation.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1054-1056
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• 2003

The slotless Permanent-Magnet Linear Synchronous Motors (PMLSM) have been developed for factory automation, transportation applications, wafer steppers, conveyance system, and so on. The current analysis and design are treated in air-cored PMLSM. This paper presents a design and analysis solutions for the general class of iron-cored Permanent magnet Linear Synchronous motor (PMLSM). In our design and analysis, rotor consisting of permanent magnets and slot less iron-cored coil stator are treated in a uniform way via vector potiential. For one such motor structure we give analytical formulas for its magnetic field, opitimal permanent magnet and winding coil thickness, trust force. We also provide comparisons of three types in Halbach, vertical, and horizontal magnet array.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.389-392
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• 2020

In order to accurately predict the losses in the power cable, analysis of the eddy current losses in the metal sheath is required. The copper loss is easily calculated by the resistance and current of the conductor, but it is difficult to measure and predict the eddy current generated from the metal sheath. For this purpose, the previous study analyzed the eddy current loss in single phase cable, but there is a limit to apply it because three phase cables are used in real environment. Therefore, in this paper, the eddy current loss occurring in the metal sheath of three phase cable according to the cause was analyzed theoretically. In addition, the eddy current loss occurring in the triangular and horizontal array were predicted through electromagnetic numerical analysis.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.3
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• pp.8-14
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• 2012

Improving the speed of image processing is in great demand according to spread of high quality visual media or massive image applications such as 3D TV or movies, AR(Augmented reality). SIMD computer attached to a host computer can accelerate various image processing and massive data operations. MAMS is a multi-access memory system which is, along with multiple processing elements(PEs), adequate for establishing a high performance pipelined SIMD machine. MAMS supports simultaneous access to pq data elements within a horizontal, a vertical, or a block subarray with a constant interval in an arbitrary position in an $M{\times}N$ array of data elements, where the number of memory modules(MMs), m, is a prime number greater than pq. MAMS-PP4 is the first realization of the MAMS architecture, which consists of four PEs in a single chip and five MMs. This paper presents implementation of image processing algorithms and performance analysis for MAMS-PP16 which consists of 16 PEs with 17 MMs in an extension or the prior work, MAMS-PP4. The newly designed MAMS-PP16 has a 64 bit instruction format and application specific instruction set. The author develops a simulator of the MAMS-PP16 system, which implemented algorithms can be executed on. Performance analysis has done with this simulator executing implemented algorithms of processing images. The result of performance analysis verifies consistent response of MAMS-PP16 through the pyramid operation in image processing algorithms comparing with a Pentium-based serial processor. Executing the pyramid operation in MAMS-PP16 results in consistent response of processing time while randomly response time in a serial processor.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.220-227
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• 2013

This study examined the electric power quantity derived from solar radiation after installing a photovoltaic power generation system on the rooftop of building adjacent to a greenhouse with a view to reducing the operating expenses of the greenhouse by securing electric energy required to run it. Results of the study can be summed up as follows: The maximum, mean, and minimum solar radiation on the horizontal plane was $26.1MJ{\cdot}m^{-2}$, $14,0MJ{\cdot}m^{-2}$, and $0.6MJ{\cdot}m^{-2}$, respectively and individual the daily electric energy generated was about 6.1 kWh, 3.7 kWh, and 0.01 kWh. The cumulative total amounts of solar radiation and electric energy was about $4,378.2MJ{\cdot}m^{-2}$ and 1,163.2 kWh, respectively. Maximum, mean and minimum cumulative electric energy consumed through each load respectively was 4.5 kWh, 2.4 kWh, and 0.0 kWh and the cumulative electric energy were 739.2 kWh, which accounted for about 63.5% of generated power. In case of the mean amount of power consumption of the system used for this study, the small capacity of heater and the short operating hours meant there was enough power; while big capacity of heater led to a shortage, and if the array surface temperature increased relatively, the energy became proportionate to solar radiation and generated power does not increase. The correlation coefficient between the two factors was 0.851, which indicates a high correlation coefficient.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.61-70
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• 2008

This paper designed the antenna for collecting and servicing the traffic information that apply to freeway Traffic Management System, as using DSRC (Dedicated Short Range Communication). Active DSRC is the technology that is using 5.8GHz Radio Frequency to a mean Sequency and there are a lot of the case occurring a physical electric wave shadowing because of the traveling straight of a electric wave. In such inferior communication environment, it constructed the stabilized communication link that can do collecting and servicing the correct traffic information and designed the beam pattern considering the establishment position of the antenna that can apply to various road environments and a communication area. By considering the communication link environment, this paper designed and manufacture the mean frequency of 5.8GHz, the input loss of -17dB in 75MHz bandwidth, the Axial ratio of 1.5:1, and $2{\times}4$ array microstrip antenna which beam pattern have the characteristic of $55^{\circ}$ horizontal half power beam width and $26^{\circ}$elevation half power beam width and the minimum establishment height of the antenna was designed as 14m for avoiding electric wave shadowing on a physical condition between vehicles

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.403-414
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• 2004

In the accompanying paper, we proposed a real. time volumetric imaging method using a cross array based on receive dynamic focusing and synthetic aperture focusing along lateral and elevational directions, respetively. But synthetic aperture methods using spherical waves are subject to beam spreading with increasing depth due to the wave diffraction phenomenon. Moreover, since the proposed method uses only one element for each transmission, it has a limited transmit power. To overcome these limitations, we propose a new real. time volumetric imaging method using cross arrays based on synthetic aperture technique with linear wave fronts. In the proposed method, linear wave fronts having different angles on the horizontal plane is transmitted successively from all transmit array elements. On receive, by employing the conventional dynamic focusing and synthetic aperture methods along lateral and elevational directions, respectively, ultrasound waves can be focused effectively at all imaging points. Mathematical analysis and computer simulation results show that the proposed method can provide uniform elevational resolution over a large depth of field. Especially, since the new method can construct a volume image with a limited number of transmit receive events using a full transmit aperture, it is suitable for real-time 3D imaging with high transmit power and volume rate.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.170-179
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• 1999

The SUS (Signal, Underwater Sound)-OAT experiment was carried out in the Ulleung Basin of the East Sea on 3 June 1997. The SUS-OAT system consisted of aircraft deployed shots as sources and a vertical line array (VLA) tethered by a receiver ship was used to survey a large area where a mesoscale warm eddy appears frequently. The experiment was carried out such that explosive charges set to detonate at 800 ft depth were dropped in a rectangular ($120{\times}120$ km). Sources were a rapidly deployable SUS charge (MK 61 MOD 0), and receiver is a fixed VLA, 90 m in length (150-240 m in receiver depth), composed of 10 elements equally spaced. The reference ray paths are computed by range-dependent acoustic model in canonical ocean based on the historical data. The singular value decomposition (SVD) method is used to obtain the horizontal perturbation of the temperature fields. Horizontal distributions of temperature fields at 150 m and 200 m depth show a weak warm eddy observed by AXBT and the inversely estimated temperature shows similar patterns in terms of the location of the warm eddy. In conclusion, the SUS-OAT experiment has been successful to estimate the position of warm eddy and its temperature field in the East Sea of Korea.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.165-170
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• 2014

Shear horizontal (SH) waves propagate as a type of plate wave in a thin sheet. The dispersion characteristics of SH waves can be used for signal analysis. Therefore, SH-waves are useful for monitoring the structural health of a thin-sheet-structure. An electromagnetic acoustic transducer (EMAT), which is a non-contact ultrasonic transducer, can generate SH-waves easily by varying the shape and array of magnets and coils. Therefore, an EMAT can be applied to an automated ultrasonic testing system for structural health monitoring. When used as a sensor, however, the EMAT has a weakness in that electromagnetic interference (EMI) noise can occur easily in the automated system because of motors and electric devices. Alternatively, a fiber optic sensor works well in the same environment with EMI noise because it uses a light signal instead of an electric signal. In this paper, a fiber Fabry-P$\acute{e}$rot interferometer (FFPI) was proposed as a sensor to receive the SH-waves generated by an EMAT. A simple test was performed to verify the performance of the FFPI sensor. It is thus shown that the FFPI can receive SH-wave signals clearly.