• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.3
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• pp.246-253
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• 2002

This paper describes the development and the field application of the ultrasonic gas flowmeter for accurate measurement of the volumetric flow rate of gases in a harsh environmental conditions in iron & steel making company. This ultrasonic flowmeter is especially suited for measuring LDG, COG, BFG gases produced in iron & steel making process. This is a transit time type ultrasonic flowmeter. We have developed the transmitting & receiving algorithm of ultrasonic wave and the ultrasonic signal processing algorithm to develope a transit time type ultrasonic flowmeter. We have evaluated the performance of ultrasonic flowmeter by the calibration system with Venturi type standard flowmeter. We has confirmed its reliability by extensive field tests for a year in POSCO, iron & steel making company. Now we have developed the commercial model of ultrasonic flowmeter and applied to the POSCO gas line.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.178-203
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• 2018

In this paper, authors have been evaluated the Frame Error Rate (FER) performance of IEEE 802.11 a/g/p standard 5 GHz frequency band WLAN over Rayleigh and Rician distributed fading channels in presence of Additive White Gaussian Noise (AWGN). Orthogonal Frequency Division Multiplexing (OFDM) based transceiver is implemented by using real-time signal processing frameworks (IEEE 802.11 Blocks) in GNU Radio Companion (GRC) and Ettus USRP N200 is used to process the symbol over the wireless radio channel. The FER is calculated for each sub-carrier conventional modulation schemes used by OFDM such as BPSK, QPSK, 16, 64-QAM with different punctuated coding rates. More precise SNR is computed by modifying the SNR calculation process of YANS and NIST error rate model to estimate more accurate FER. Here, real-time signal constellations, OFDM signal spectrums etc. are also observed to find the effect of multipath propagation of signals through flat and frequency selective fading channels. To reduce the error rate due to the multipath fading effect and Doppler shifting, channel estimation (CE) and equalization techniques such as Least Square (LS) and training based adaptive Least Mean Square (LMS) algorithm are applied in the receiver. The simulation work is practically verified at GRC by turning into a pair of Software Define Radio (SDR) as a simultaneous transceiver.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.3
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• pp.156-163
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• 2003

Most watermarking techniques insert watermarks into transform coefficients in the frequency domain because we can consider robust or imperceptible frequency bands against malicious attacks to remove them. However, parameterization of 3-D data is not easy because of irregular attribution of connectivity information, while 1-I) or 2-D data is regular. In this paper we propose a new watermarking scheme for 3-D polygonal mesh models in the DCT domain. After we generate triangle strips by traversing the 3-D model and transform its vertex coordinates into the DCT domain, watermark signals are inserted into mid-frequency bands of AC coefficients for robustness and imperceptibility. We demonstrate that our scheme is robust against additive random noise, the affine transformation, and geometry compression by the MPEG-4 SNHC standard.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.19-29
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• 2001

The Pan-European Digital Audio Broadcasting(DAH) system's performance is characterized and improved with the aid of turbo codec. From the fact that the first bit among the four coded bits at the RCPC coding defined in the Eureka 147 DAD system is not. punctured and always transmitted, this paper proposes a new turbo coded DAB system model that replaces the existing RCPC codec by a turbo codec without modifying the puncturing procedure and puncturing vectors defined in the standard DAB system for compatibility. The performance of a new system is compared to that of the conventional system under the Rician fading channel and the Rayleigh fading channel in conjunction with DAD transmission mode I and III suitable for the terrestrial single frequency network and satellite broadcasting.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.233-239
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• 2006

As the number of aged-housing has been rapidly increased, many kinds of defects and problems such as degeneration of housing environment, structural performance, and equipment performance have been appeared. The reconstruction as the way to improve the aged-housing has been used mostly because the legal process of the reconstruction is relatively easy. On the other hand, it has caused problems such as the lack of natural aggregate, the environmental damages owing to construction wastes, the loss of national resources, and the lack of the housing for rent nearby the reconstruction area. This problems limit active tying into the reconstruction business at present in the industrial and political perspective. In this context, it is required to revitalize the remodeling rather than the reconstruction. In order to reach this objective, this research aims at identifying the user-oriented performance for the housing industry and developing the new technologies. It is expected that the result of this research can contribute to more revitalize the remodeling as tying researches in terms of design, structure, equipment, and construction.

• Ocean and Polar Research
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• v.39 no.2
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• pp.159-168
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• 2017

To evaluate the accuracy of UAV photogrammetry for Hyangho coast, eastern coast of Korea, we conducted a field experiment wherein UAV photogrammetry test was repeated three times. Since the Haygho coast is located within a military reservation zone, it was necessary to obtain permission to gain access to the beach and to have sensitive aerial photographs showing military facilities inspected and cropped. The standard deviation of the UAV shooting position between the three tests was less than 1 m, but repeatability of footprint on the ground was low due to wind-driven variability of the UAV pose. Self-calibrating bundle adjustment(SCBA) of implementing non-metric camera calibration was failed in one test. In two tests, the vertical error was twice as large as the pixel size except for those areas that were subject to security inspection and cropping. Given the problems that can arise with regard to the repeatability of the shooting area as well as the possibility of failure with regard to SCBA, we strongly recommend that UAV photogrammetry in coastal areas needs to be repeated at least twice.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.157-161
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• 2011

The study for traffic safety improvement is so necessary to minimize the wound of pedestrian at car impact as to prevent pedestrian from this accident. This study aims at analyzing the behavior affected by impact on which car body hits pedestrian. Load and damage of pedestrian are also investigated. This model is the small car body as frame structure. The pedestrian is modeled with dummy by CATIA as Korean standard body style. The ear impacts the side of pedestrian with the speed from 30 to 90km/h. Behavior and damage of pedestrian at impact are analyzed by ANSYS. In case of 30km/h, The maximum pressure of dummy becomes the maximum value of 100MPa after the elapsed time of 0.1second and then seems to remain at 105MPa constantly. In case of 60km/h, its pressure becomes the maximum value of 110MPa at the elapsed time of 0.05second and decreases at 90MPa until the elapsed time of 0.1second. This value fluctuates after the elapsed time of 0.1second. In case of 90km/h, its maximum pressure becomes the maximum value of 155MPa at the elapsed time of 0.07second and fluctuates after the elapsed time of 0.07second until O.3second. This value seems to remain at 100MPa constantly after 0.3second until 0.5second. But this pressure increases suddenly just after 0.5second. Maximum deformations of dummy increase linearly according to elapsed time at hitting velocities of 30, 60 and 90km/h.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.3
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• pp.19-29
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• 2010

In South Korea, as the living standard has been getting higher, meat consumption is steadily increasing. To meet the country's demand, livestock houses become larger and wider with increased raising density. In larger livestock houses, pollutants such as flake of pig skin, excrement, odor, various dusts and noxious gas like ammonia are excessively accumulated inside the facility. These will cause weak immunity for the pigs, diminution of productivity and degeneration of working condition. These problems can be solved through the ventilation performance of the facility. In the winter time, ventilation must be controlled to minimum to maintain a suitable thermal condition. However, this affects the other internal environmental condition because of the minimum ventilation. The installation of "wet air cleaner" especially in the winter time can be an alternative solution. For efficient application of this machine, there is a need to understand the existing ventilation condition and analyze the interaction of existing ventilation system with the wet air cleaner considering its appropriate location. In this study, the existing ventilation system as well as the internal environmental condition negatively inside the facility with the wet air cleaner has been studied using CFD technology. The CFD simulation model was validated from the study conducted by Seo et al. (2008). Results show that the elimination rate of ammonia was 39.4 % and stability could be improved to 35.1 % (Comparing case 5 to 1 where wet air cleaner machine was not used). It can therefore be concluded that case 5 shows the optimum location of a wet air cleaner in the livestock house.

• Korean Journal of Food Science and Technology
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• v.40 no.1
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• pp.111-114
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• 2008

Adsorption isotherm with the most fundamental information related to chromatography process is obtained experimentally. The adsorption isotherm of 2-deoxyuridine (dUrd) and 2-deoxycytidine (dCyd) with ${\mu}$-Bondapak $C_{18}$, static method was adopted in RP-HPLC. The concentrations of mobile and stationary phases were measured with different initial concentrations of dUrd and dCyd, 1, 3, 5, 7, 10 mg/mL, respectively. The adsorption isotherm data were applied by Freundlich, Langmuir, Sips, and Radke-Prausnitz model equations. As a result of the regression analysis, standard error between adsorption isotherm of dUrd and Radke-Prausnitz equation was very low, and adsorption isotherm of dCyd was in an agreement with Sips equation very well.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.423-431
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• 2011

Warfighting experimentation is an important process for identifying requirements against changing military environment and for verifying proposed measures for reforming military service. The wargame simulation experiment is regarded as one of the most effective means to warfighting experimentation, and its importance is increasing than ever. On the other hand, the results of wargame experiments could be unreliable due to the uncertainty involved in the experimental procedure. To improve the reliability of the experimental results, systematic experimental procedures and analysis methods must be employed, and the design and analysis of experiments technique can be used effectively for this purpose. In this paper, AWAM, a wargame simulator, is used to optimize the organization of operational troops. The simulation model describes a warfighting situation in which the 'survival rate of our force' and the 'survival rate of the enemy force' are considered as responses, 'the numbers of weapons in the squad' as control factors, and 'the uncontrollable variables of the battlefield' as noise factors. In addition, for the purpose of effective experimentation, the product array approach in which the inner and outer orthogonal arrays are crossed is adopted. Then, the signal-to-noise-ratio for each response and the desirabilities for the means and standard deviations of responses are calculated and used to determine a compromise optimal solution. The experimental procedures and analysis methods developed in this paper can provide guidelines for designing and analyzing wargame simulation experiments for similar warfighting situations.