• The Journal of the Korea Contents Association
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• v.9 no.5
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• pp.84-90
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• 2009

In this paper, the new channel estimation was proposed that have the low complexity and high performance using Fuzzy inference method uses recently from various field for estimation about uncertainty in channel estimation of OFDM. Proposed method is channel estimation performance improve, calculation and interpolation for statistics character of channel using the pilot before LS channel estimation by Fuzzy inference method. Simulation result in QPSK proposed channel estimation method shows the enhancement of 5.5dB compared to the LS channel estimation and the deterioration of 1.3dB compared to the MMSE channel estimation in mean square error point $10^{-3}$. symbol error rate shows similarity performance the MMSE $10^{-1.96}$, proposed channel estimation $10^{-1.93}$ and enhancement of $10^{-0.35}$ compared to the LS channel estimation in signal to noise ratio point 20dB.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.238-248
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• 2008

This study investigated mercury emission at various combustion conditions and analyzed mercury species in flue gas from coal combustion at a laboratory scale furnace in coal. The results of this study can be used to predict and to assess mercury emission at coal boilers and power plants. The coal used in the plants generally contains about $0.02{\sim}0.28\;mg$ of mercury per kg. Bituminous and anthracite coal used for the experiment contained 0.049 and 0.297 mg/kg of mercury, respectively. Mercury emissions during coal combustion at temperatures range of $600^{\circ}C$ to $1,400^{\circ}C$ was measured and analysed using Ontario Hydro method; the speciation changes were also observed in mercury emissions. The results showed higher fraction of elemental mercury than that of oxidised mercury at most temperatures tested in this experiment. The fraction of elemental mercury was lower in combustion of anthracite coal than in bituminous combustion. As expected, equilibrium calculations and real power plants data showed good similarity. The distribution of particle size in flue gas had the higher peak in size above $2.5\;{\mu}m$. However the peak of mercury enrichment in dust was at $0.3\;{\mu}m$, which could be easily emitted into atmosphere without filtration in combustion system. When the CEA(Chemical equilibrium and Application) code was used for combustion equilibrium calculation, Cl was found to be the important component effecting mercury oxidation, especially at the lower temperatures under $900^{\circ}C$.

• Journal of Korea Multimedia Society
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• v.13 no.2
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• pp.298-307
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• 2010

The grass is one of important components that cover the wide surfaces in the application such as game or real time simulation. Actually, it not easy to render effectively numerous grasses that grow over the wide terrain. To solve the difficulty, we must find a solution to the two contradictions in terms : quality and calculation cost. As a solution to the above-mentioned task, in this paper, we propose an efficient method to represent the natural grasses by introducing fractal theory and instancing technique. Although the existing grass representation methods make use of a simple rule of applying a basic grass model repeatedly in rendering process, on the contrary we take advantage of the basic property of fractal's self-similarity and we devise a natural representation method suited to the given environment by introducing two important growth factors such as nature of terrain and quantity of light, and finally we apply a GPU-based shader instancing technique to rendering numerous grass models in real-time.

• Investigative Magnetic Resonance Imaging
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• v.24 no.3
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• pp.123-131
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• 2020

Purpose: Joint label fusion (JLF) is a popular multi-atlas-based segmentation algorithm, which compensates for dependent errors that may exist between atlases. However, in order to get good segmentation results, it is very important to set the several free parameters of the algorithm to optimal values. In this study, we first investigate the feasibility of a JLF algorithm for prostate segmentation in MR images, and then suggest the optimal set of parameters for the automatic prostate segmentation by validating the results of each parameter combination. Materials and Methods: We acquired T2-weighted prostate MR images from 20 normal heathy volunteers and did a series of cross validations for every set of parameters of JLF. In each case, the atlases were rigidly registered for the target image. Then, we calculated their voting weights for label fusion from each combination of JLF's parameters (r_pxy, r_pz, r_sxy, r_sz, β). We evaluated the segmentation performances by five validation metrics of the Prostate MR Image Segmentation challenge. Results: As the number of voxels participating in the voting weight calculation and the number of referenced atlases is increased, the overall segmentation performance is gradually improved. The JLF algorithm showed the best results for dice similarity coefficient, 0.8495 ± 0.0392; relative volume difference, 15.2353 ± 17.2350; absolute relative volume difference, 18.8710 ± 13.1546; 95% Hausdorff distance, 7.2366 ± 1.8502; and average boundary distance, 2.2107 ± 0.4972; in parameters of r_pxy = 10, r_pz = 1, r_sxy = 3, r_sz = 1, and β = 3. Conclusion: The evaluated results showed the feasibility of the JLF algorithm for automatic segmentation of prostate MRI. This empirical analysis of segmentation results by label fusion allows for the appropriate setting of parameters.

• Archives of design research
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• v.14 no.1
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• pp.27-34
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• 2001

In order to design the products that impression or emotional taste influence the purchase, feedback is necessary as useful data for better idea sketches through users emotional evaluation in early stage of design process. On the other hand, it was required to make judgments individually in previous image evaluations for emotional evaluations such as semantic differential method (SD method) that objects have been considered as classified tendency. However those SD methods are not enough to reflect flexible human capability with similarity judgment in object perceptual process. Therefore, this study proposes a classification of stimulus based on intuitive judgment and a hierarchical image evaluation method based on analysis of hierarchical process and fuzzy integration. The evaluation will be conducted through the order of process, intuitive classification of objective stimulus and items, definition of representatives in each class. Evaluation for each image of the stimulus, calculation of prior raking based on fuzzy integration. The evaluation supportive software is developed to conduct this evaluation process under interactive environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.90-101
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• 2009

An objective of this study is to suggest a procedure to evaluate vehicle emissions regardless of the driving pattern. Field experiments using portable emission measurement system were conducted under the real world driving cycle. Standardized average for NOx, $CO_2$ emission and fuel consumption rates were calculated while the vehicle specific power distribution within each vehicle speed bin was taken into consideration. Composite emission factor and fuel economy, which were obtained based on the standardized average results and traffic statistics, showed good similarity to those acquired through the conventional chassis dynamometer tests qualitatively as well as quantitatively. Considering that a conventional method obviously has a limitation to reflect various characteristics of the real world, the new approach suggested in this study can be used as an alternative procedure to collect more specific data to establish the mobile emission factors.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.6
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• pp.51-58
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• 2012

Scirtothrips Dorsalis (Thysanoptera: Thripidae) recently has been recognized as a major source of the pest damage in the citrus fruit orchards. So its arrival has been predicted periodically but it is difficult to identify adults of the pest with the naked eyes because of their size smaller than the 0.8mm. In this paper, we propose a method to detect candidate areas for automatic identification of Scirtothrips Dorsalis on forecasting traps. The proposed method uses a histogram-based template matching where the composite image synthesized with the gray-scale image and the gradient image is used. In our experiments, images are acquired by the optical microscopy with 50 magnifications. To show the usefulness of the proposed method, it is compared with the method we previously suggested. Also, the performances when the proposed method is applied to noise-reduced images and gradient images are examined. The experimental results show that the proposed method is approximately 14.42% better than our previous method, 41.63% higher than the case that the noise-reduced image is used, and 21.17% higher than the case that the gradient image is used.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.3
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• pp.41-48
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• 2012

Using multi-sensor or multi-temporal high resolution satellite images together is essential for efficient applications in remote sensing area. The purpose of this paper is to estimate geometric difference of translations between high-resolution optical and SAR images automatically. The geometric and radiometric pre-processing steps were fulfilled to calculate the similarity between optical and SAR images by using Mutual Information method. The coarsest-level pyramid images of each sensor constructed by gaussian pyramid method were generated to estimate the initial translation difference of the x, y directions for calculation efficiency. The precise geometric difference of translations was able to be estimated by applying this method from coarsest-level pyramid image to original image in order. Yet even when considered only translation between optical and SAR images, the proposed method showed RMSE lower than 5m in all study sites.

• Journal of Environmental Science International
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• v.15 no.10
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• pp.919-928
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• 2006

The present study applied an atmospheric flow field model in Gwangyang-Bay which can predict local sea/land breezes formed in a complex terrain lot the development of a model that can predict short term concentration of air pollution. Estimated values from the conduct of the atmospheric flow field were used to evaluate and compare with observation data of the meteorological stations in Yeosu and the Yeosu airport, and the effect of micrometeorology of surround region by the coastal area reclamation was predicted by using the estimated values, Simulation results, a nighttime is appeared plainly land breezes of the Gwangyang-bay direction according to a mountain wind that formed in the Mt. of Baekwooun, Mt. of Youngchui. Land winds is formed clockwise circulation in the north, clockwise reverse direction in the south with Gangyang-bay as the center. Compared with model and observation value, Temperature is tend to appeared some highly simulation value in the night, observation value in the daytime in two sites all, but it is veil accorded generally, the pattern of one period can know very the similarity. And also, wind speed and wind direction is some appeared the error of observation value and calculation results in crossing time of the land wind and sea land, it can see that reproducibility is generally good, is very appeared the change land wind in the nighttime, the change of sea wind in the daytime. And also, according to change of the utilization coefficient of soil before and after development with Gwangyang-Bay area as the center. Temperature after development was high $0.55\sim0.67^{\circ}C$ in the 14 hoots, also was tend to appear lowly $0.10\sim0.22^{\circ}C$ in the 02 hours, the change of u, v component is comparatively tend to reduced sea wind and land wind, it is affected ascending air current and frictional power of the earth surface according to inequality heating of the generation of earth surface.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.477-484
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• 2014

Caldera is a large depression commonly formed by collapse of the ground following explosive eruption of a large body of stored magma. On earth, calderas and caldera complexes range in size from kilometers to tens of kilometers. Historical eruptions associated with caldera collapse have led to huge fatalities in Indonesia as well as left global impacts. This study presents case study on calderas in Indonesia which resembles to Mount Baekdu located at the border of China and North Korea; in the perspectives of similar characteristics, principal hazard, recent symptom of volcanic activity and the threat if eruption occurs in the near future. Calculation by using weighted evaluation matrix for Mount Krakatau, Mount Tambora, Mount Ijen, Tengger Caldera, Mount Rinjani and Ranau Caldera were taken for the selection of a site for future case study.