• The Journal of Information Technology
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• v.7 no.2
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• pp.69-76
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• 2004

This paper presents the results of spectral analysis about waveforms and leakage current waveforms on contaminated silicon insulators under various environment conditions.(salt fog, clean fog, rain). The larger the leakage current during 200ms, the higher the power spectrum at 60Hz. If contaminated insulators suffers from high salt density fog, the leakage current occurs with high crest value intermittently, results in the low spectrum. Analysis of leakage current data showed that this electrical activity was characterized by transient arcing behavior contaminants are deposited on the insulator surface during salt fog tests. This provides a path for the leakage current to flow along the surface of the insulator. It is important to have an indication of the pollution accumulation in order to evaluate the test performance of a particular insulator. If the drop in surface resistivity is severe enough, then the leakage current may escalate into service interrupting flashover that degrade power quality.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.889-893
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• 2007

Now various research apply Fractal and chaos theory for natural expression of the fog on the fluid that the present this studies use special tools applicable are possible expression such as nature. But, ordinary peoples these works are much difficult yet easy to express, because require high prices and high professionals. Therefore, it is general assignments that everybody need easily expression of fog from high price special tools and professional programming reduction of complication difficult. Embodying this 2D image study made easily various image expression to be possible until UCC, individual from professional broadcasting. Specially, This study can use easily background fog expression when need to image expression such as Korean traditional pictures 3D because of possible expression of fog fluid effect in 3D space.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.89-98
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• 2015

PURPOSES : The objective of this study is to evaluate the performance properties of chip seals and fog seals with polymer-modified emulsions. METHODS : The performance of chip seals and fog seals was evaluated on the basis of common issues in surface treatments. Granite aggregate and four types of asphalt emulsions (one of the unmodified and three of the modified emulsions) were used considering the usage in field. A Vialit test was performed to determine the aggregate retention, and the MMLS3 (Third Scale Model Mobile Load Simulator) test was conducted to determine the aggregate retention, bleeding, and rutting. In addition, the fog seal specimens were tested by the BPT (British Pendulum Test) to evaluate skid resistance. RESULTS AND CONCLUSIONS : Overall, the polymer-modified emulsions (PMEs) showed better aggregate retention and bleeding resistance for both chip seals and fog seals. When comparing the performance of the PMEs, the difference was not considerable. In addition, PMEs present significantly better rutting resistance than unmodified emulsions. For skid resistance, if the recommended mix design is applied, the specimens do not cause issues with skid resistance. Although all of the fog seal specimens were over the criteria for skid resistance, the specimen fabricated by the high emulsion application rate (EAR) of the unmodified emulsion was nearly equivalent to the skid value criteria. Therefore, the use of an unmodified emulsion with a high EAR should be carefully applied in the field.

• Proceedings of the KSRS Conference
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• v.2
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• pp.664-667
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• 2006

Seasonal threshold values for fog detection over the ten airport areas in the Korean Peninsula have been derived, using the satellite-observed data of polar-orbit (Aqua/Terra MODIS) and geostationary (GOES-9) during two years. The values are obtained from reflectance at 0.65 ${\mu}m$ $(R_{0.65})$ and the difference in brightness temperature between 3.7 ${\mu}m$ and 11 ${\mu}m$ $(T_{3.7-11})$. In order to examine the discrepancy between the threshold values of two kinds of satellites, the following parameters have been analyzed under the condition of daytime/nighttime and fog/clear-sky, utilizing their simultaneous observations over the Seoul Metropolitan Area. The parameters are the brightness temperature at 3.7 ${\mu}m$ $(T_{3.7})$, the temperature at 11 ${\mu}m$ $(T_{11})$, and $T_{3.7-11}$ for day and night. The $R_{0.65}$ data are additionally included in the daytime. The GOES-9 thresholds over the nine airport areas except the Cheongju airport have revealed the accuracy of 60% in the daytime and 70% in the nighttime, based on statistical verification as follows; FAR, POD and CSI. However, the accuracy decreases in the foggy cases with twilight, precipitation, short persistence, or the higher cloud above fog.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.27-32
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• 2018

IoT technology is developing with various application areas in $4^{th}$ Industrial revolution. There are many users using the application services. Sensing data from various environment need to be transferred to cloud computing storage and store in the cloud storage. However, physical distance from the end node to cloud computing storage is far away, and it is not efficient to transfer data from sensors and store the sensing data in the cloud storage whenever sensing data happen. Therefore, Fog computing is proposed to solve these problems which can process and store the sensing data. However, Fog computing is new emerging technology, there is no standard security model and requirements. This research proposes to security requirements and security model for Fog computing to establish a secure and efficient cloud computing environment.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.485-490
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• 2017

In this paper, we propose a technique for high speed removal of sea-fog using a graphic processor. This technique uses a host processor(CPU) and several graphics processors(GPU) capable of parallel processing to remove sea-fog from the input image. In the process of removing sea-fog, the dark channel extraction, the maximum brightness channel extraction, and the calculation of the transmission are performed by the host processor, and the process of refining the transmission by applying the bidirectional filter is performed in parallel through the graphic processor. To verify the proposed parallel processing method, three NVIDIA GTX 1070 GPUs were used to construct the verification environment. As a result, it takes about 140ms when implemented with one graphics processor, and 26ms when implemented using OpenMP and multiple GPGPUs. The proposed a parallel processing algorithm based on the graphics processor unit can be used for safe navigation, port control and monitoring system.

• Environmental Engineering Research
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• v.14 no.2
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• pp.88-94
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• 2009

In this study an attempt has been made to predict the annual foggy days over Gyeongsangbuk-do of Korea, using the regional mesoscale model (MM5). The annual meteorological conditions are simulated, and the annual and seasonal foggy days are predicted from the simulated results based on the seasonal and spatial information of the observed meteorological characteristics for fog occurrence such as wind speed, relative humidity, and temperature. Most of observed inland fog over Gyeongsangbuk-do occurs in autumn under the meteorological conditions such as a cairn, a high temperature range (above $10^{\circ}C$), and a high relative humidity (above 85%). The predicted results show the various foggy days, about 10${\sim}$60 days, depending on the season and the site locations. The predicted annual foggy days at inland sites are about 30${\sim}$60 days, but at coastal sites, about 10${\sim}$20 days. Also, a higher frequency of fog occurrence at inland sites is shown in autumn (about 60% of the annual foggy days). Otherwise, a higher frequency of fog occurrence at coastal sites is shown in summer (about 60% of the annual foggy days), unlike the inland. These annual foggy days and their seasonal variations agree reasonably well with the observed values. It can be concluded that it is possible to predict the occurrence of annual or seasonal foggy days by MM5.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.53-63
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• 2013

PURPOSES: The purpose of this study was to investigate the disintegration mechanism of concrete due to the infiltration of the moisture to the milling overlay pavement and to come up with a method to minimize the disintegration as well as verifying the effectiveness of the edge sealing and Fogseal method. METHODS : This study investigated the distress mechanism due to the infiltrated moisture remaining in the milling overlay pavement through chloride freezing test and verified the effectiveness of the sealing of the milling edge and fog seal methods, which have been devised to minimize the moisture infiltration, through laboratory water permeability test. Additionally, long-term pavement performance was compared for the effectiveness of the proposed method through under loading test, and field water permeability test was carried out to verify the field applicability of the proposed method. RESULTS: The result of the research confirmed that chloride deteriorates the concrete surface through disintegration and lowers its strength and that the laboratory moisture infiltration test verified the effectiveness of the milling edge sealing and fog seal methods in the deterrence of moisture infiltration to the overlay pavement with excellent long-term performance of the pavement treated with the proposed method. Although the field water permeability test revealed some deterrence of moisture infiltration of the milling edge sealing and fog seal methods to a certain extent, the difference was a little. CONCLUSIONS: The milling edge sealing and fog seal methods are limited in their effectiveness for the cases of improvident compaction management or mixture with large void, and it is believed that installation of subsurface drainage is more effective in these cases.

• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.375-380
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• 2017

This paper has proposed a single image based fog degree quantification method by measuring both transmission and local contrast. The proposed method estimates the foggy expected regions from transmission, and then assesses the size of regions of which transmission values are foggy expected ones and the range of local contrast value on such regions. Compared with fog degree gauged by the scattering coefficient measurement sensor, the proposed method quantifies the fog degree with more than 95% accuracy for images containing various objects and environments. We also developed a technique that measures the local contrast values in process of measuring transmission values. So, the proposed method does not increase complexity compared to the existing transmission method.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.1
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• pp.299-308
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• 1999

Purpose: The purpose of this study was to compare the qualities of the four different processing chemicals (solutions). Materials and Methods: With EP 21 films(Ektaspeed plus film, Kodak Co., USA), nine unexposed and nine exposed films of a step wedge were processed utilizing automatic film processor(XR 24, Durr Co., Germany) for 5 days. During 5 days, the total number of processed films including out-patient' s intraoral films were about 400-500 for each brand. Base plus fog density, film density, contrast of processed films were measured with densitometer(model 07-443 digital densitometer, Victoreen Co., USA). These measurements were analyzed for comparison. Results: The results were as follows, 1. For the base plus fog density. there was significant difference among the four chemicals (p<0.05). The sequence of the base plus fog densities was in ascending order by Kodak, X-dol 90. Agfa and Konica. 2. For the film density. all chemicals showed useful range of photographic densities(0.25-2.5). The sequence of the film densities was in ascending order by Kodak, X-dol 90, Konica and Agfa. But there was no statistically significant difference of film density between X-dol and Kodak (p<0.05). 3. The sequence of the contrasts was in ascending order by Konica, X-dol 90, Kodak and Agfa. But there was no statistically significant difference of contrast between X-dol and Konica (p<0.05). Conclusion: These results indicated that the four processing chemicals had clinically useful film density and contrast. but only Kodak processing chemical had useful base plus fog density.