• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.4
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• pp.481-486
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• 2011

Recently, most presentations have been presented on the screen using the computer. This paper suggests that the computer can be controlled by the gesturing recognition, without the help of any person or tools. If we use only information in the form of images, we should have a high-resolution camera for capturing the images and a computer that can treat high-resolution images. However, this paper will present a solution whereby a low-resolution camera can be used at the stage. It uses the supersonic sensor to trace the presenter's location and a low-resolution camera for capturing the necessary limited and small area. The gesture is defined by the number of fingers and one's hand positions which are recognized by the Erosion / Dilation and Subtraction algorithm. The system this paper addresses has improved 13%, when comparing tests between the image-only data system and this paper's system. The gesture recognition tests have a 98% success rate.

• Journal of Environmental Impact Assessment
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• v.19 no.6
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• pp.563-571
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• 2010

In carrying out the prior review on environmental conditions for basic plan of public waters reclamation, the important item is review on conditions of location on prearranged reclaimed land. In this study, environmental assessment which needs careful consideration in the first stage of selecting location is presented by analyzing environmental impact assessment on public waters reclamation projects for about 10 years. The assessment index for alternative comparison is divided into two parts according to importance level. What is most important in alternative comparison is the comparison on direct influence due to reclamation. In other words, it figures out damaged extent of natural shoreline as well as intertidal and infralittoral zones. Comparing influence extent due to reclamation through the 1st comparison on this is regarded as to be important. In case there is no significant difference by alternatives through the 1st assessment, the 2nd assessment should be carried out. In the 2nd assessment indexes are damaged quantity of benthic organism, change in seawater current, erosion, accumulation and exchangeable rate of seawater. The plan for selecting optimal location which minimizes environmental influence in establishing public waters reclamation plan is demonstrated through model cases. For this, 3 districts which have similar environment and scale are selected, and then comparison on location alternative is made through environmental assessment index. In addition, the comparison on 3 arrangement alternatives are conducted, targeting certain areas. It is thought that carrying out comparison review on respective areas in the same cities and counties, not merely comparing arrangement plan by selecting 1 targeting area in advance, is the most appropriate. Besides, selection of arrangement plan considering environment, which minimizes damage of natural shoreline and influence due to change of seawater current is required in alternative comparison on arrangement plan as well. In case of the prior review on environmental conditions though alternative comparison method presented in this study is carried out, it is safely said that the influence on ocean environment due to public waters reclamation can be minimized.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.3
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• pp.47-53
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• 1999

This study was carried out to suggest the slope revegetation technology of biological engineering using the Ligustrum obtusifolium, which is one of the pioneer plant species. Ahead of the experimental construction, we evaluated the L. obtusifolium's value of biological engineering for the slope stabilization by testing the growth rate after the cuttings were buried for 8 weeks('98. 7. ~ '98. 9.). In this test, it was found that the L. obtusifolium, one of the species deep rooted with developed underground parts, is very effective for the slope stabilization and that the rooting powder(Hormex Powder) gave the better effects on root germination. In April of 1999, the experimental construction of biological engineering technology using recycled L. obtusifolium live cuttings(applied growth-stimulating compound) and green bags was conducted at sandy cut-slope in GLEN ROSS G.C.(Yongin). The slope was tolerant of soil erosion despite of heavy rainfall in the rainy season and many plant species invading for five months('99. 4. ~ '99. 9.). The vegetation research was performed through examining the frequency of each block using the transect method. 21 kinds of plant speices appeared in total area($25.5m^2$) and the dominant species are Digitaria sanguinalis, Setaria viridis, Cyperus amuricus, Persicaria blumei, Artemisia princeps var. orientalis. With regard to life forms, therophytes were shown with a dominant distribution of 66.7% of total species and neophytes relatively with a low distribution of 19.0%. Furthermore, it can be estimated that there is no ecological stabilization of this slope with the result of the ruderal species' occupation of 71.4%. It is too early to argue about ecological mechanical advantages and disadvantages of this technology, but, from the result of this study, it is expected that the slope revegetation technology of biological engineering using L. obtusifolium can be effectively applied to sandy slope(not rock or weathered rock slope) and that the early rapid stabilization and favorable succession could be done with the improvement of soil condition.

• Journal of the Korean Geographical Society
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• v.48 no.5
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• pp.615-628
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• 2013

The waterfall can be formed by difference between the height of up and down part in new channel, is formed by channel avulsion that rapidly changing of river channel course. This study described types and processes of waterfalls by channel avulsion, and analyzed rates and factors of waterfall recession, on object to 7 waterfalls in South Korea. Bulyeong falls at Uljin-gun, Yongchu falls at Yeongdeok-gun, Jikyeon falls at Yanggu-gun and Gwangpum falls at Uljin-gun are formed by natural incised meander cutoff. Samhyeongje falls at Taebaek-si and Guryong falls are formed by river capture processes, and Palbong falls at Chungju-si is formed by artificial channel cutting for farm land secured. The locations of waterfalls gradually moved to upstream over time by head erosion. The recession rates were measured by 3~4m/ka on Bulyeong falls, Yongchu falls, Jikyeon falls and Samhyeongje falls, to estimate of formation age. Recession rates of these 4 waterfalls were analyzed that have clearly positive correlations with drainage area, precipitation, corrosion and weathering capability of bedrock, and initial height of waterfall.

• Corrosion Science and Technology
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• v.11 no.6
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• pp.263-269
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• 2012

Copper alloys are commonly applied to ship's propellers, pumps and valves which are serviced in seawater due to their good castability and corrosion resistance. In the environment of high flow velocity, however, erosion damage predominates over corrosion damage. In particular, the cavitation in seawater environment accelerates surface damage to copper alloys, resulting in degradation of products and economic losses and also threatening safety. The surface was coated with WC-27NiCr by high velocity oxygen fuel(HVOF) spraying technique to attain durability and cavitation resistance of copper alloys under high velocity/pressure flow. The cavitation test was performed for the WC-27NiCr coating deposited by HVOF in seawater at the amplitude of $30{\mu}m$ with seawater temperature. The cavitation at $15^{\circ}C$ caused exfoliation of the coating layer in 17.5 hours while that of $25^{\circ}C$ caused the exfoliation in 12.5 hours. When the temperature of seawater was elevated to $25^{\circ}C$ from $15^{\circ}C$, more damage was induced by over 160%. Although WC-27NiCr has good durability, corrosion resistance and eletrochemical stability, the cavitation damage rate of the coating layer could remarkably increase at the elevated temperatures under cavitation environments.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.93-102
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• 2014

In the flood plain, river facilities such as sports facilities and ecological park are builded up since the late 2000s. The recent increase of rainfall intensity and flood frequency results in the immersions of parks and river facilities located in the flood plain. Therefore it is necessary to perform the numerical analysis for the extreme rain storm in the flood plain. In this study, to analyze the hydraulic impact by lowering and rising of the water level at flood plain, Both the FaSTMECH, which is a quasi-unsteady flow analysis model to be used for simulating the wet and dry, and the Nays2D, which is unsteady flow analysis model, are used in this study. Also, the flow velocity distribution and the inundation are compared over a period of the typhoon. As a result, the flow velocity distribution at flood plain showed very low values compared to the flow rate in the main channel. This means that the problem of sedimentation is more important than that of erosion in the flood plain.

• The Journal of Fisheries Business Administration
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• v.49 no.1
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• pp.17-35
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• 2018

This study is to evaluate economic value of the ecosystem service benefits of the marine forests provided to our society on the basis of the global standard valuation manual. The main results of this study are summarized as follows: First, the ecosystem service benefits of marine forests are worth 771,121,551 won per hectare for a year in Korea. Second, when evaluating value based on the services benefits of the marine forests, as resource provisioning service, the annual value of the fishery potential production amounts to 58,512,271 won per hectare. The annual value of the environmental and regulatory services is estimated to total 29,574,000 won per hectare including 546,488 won per hectare for climate regulation, 85,342 won per hectare for pollution purification, and 28,942,170 won per hectare for erosion protection. The annual value of the culture and tourinsm services is estimated to total 15,317,647 won per hectare including 5,011,765 won per hectare for skin scuba service and 10,305,882 won per hectare for sea fishing. Also, the aunnual non-use value is estimate to 637,800,000 won per hectare. Third, assuming that the value of the sea forests increases proportionally to the unit area, the marine forests can be valued at 12.7 trillion won per year based on 12,208.2 hectares of marine forests creation area and 4,272.6 hectares of natural seaweed beds. Fourth, the total economic value of the marine forests can be estimated at 244 trillion won in 2016, if the value of the marine forests permanently continues in the future by applying 5.5% of the social discount rate. The results of this study are expected to serve as a valuable information for improving awareness of the value of marine forests ecosystem and ensuring the validity of the marine forests creation policy by converting the value of the marine forests's ecosystem service into monetary units.

• Journal of the Korean earth science society
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• v.22 no.4
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• pp.317-326
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• 2001

The coastline of semi-enclosed Hampyung Bay, southwestern coast of Korea, consists largely of erosional sea-cliffs characterized by steep face slope, low in height (less than 3m), and composition of soft reddish soil. Recession rates of the sea-cliffs in the Haeuri coast of Hampyung Bay, which were Quantified by photogrammetry using single aerial photographs taken 1976 and 1990, respectively, were approximately 1${\sim}2m/yr. This value is in good agreement with the field measurement conducted by Chang et al. (1999). Subsequently, the photogrammetry seems to be a very useful method to measure easily long-term coastline change. This severe erosion of sea-cliff in the semi-enclosed bay environment, furthemore, is probably due to combined effects of typhoon or/and storm surges and weak resistance of soil cliff itself.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.5
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• pp.484-492
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• 2013

With the industrial acceleration in a lot of countries of the world, the demand for anti-corrosion and anti-abrasion material increases continuously. Particularly, stainless steel with the fine surface and excellent corrosion resistance is widely used in various industrial fields including ship, offshore structures tidal power plant, and etc. In marine environment, however, it is easy to generate by the corrosion damage by $Cl^-$ ion and cavitation damage due to high rotation speed on stainless steel. Therefore, in this research, the cavitation erosion-corrosion test (Hybrid test) was performed for 304 stainless steel specimen used in the high flow rate seawater environment. And the cavitation damage behavior in the corrosive environment was analyzed overall. The high hardness was shown due to the formation of compressive residual stress by the water cavitation peening effect in cavitation condition. However, high current density in the potentiodynamic polarization experiment presented with the breakdown of the passive film caused by physical impact. Therefore, both electrochemical characteristics and mechanical properties must be taken into account to improve the cavitation resistance in seawater.

• Plant Journal
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• v.14 no.2
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• pp.33-38
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• 2018

The CFB boilers technology is facing a number of challenges. Among them, boiler tube erosion, sintering by bed inventory overheating and high self consumed service power are major ones. This study was conducted to obtain allowable bed inventory with the Yeosu Power Plant, a 300 MW class CFB boiler. For the test, bed pressure was reduced from design pressure of 4.5 KPa to 2.5 KPa by reducing bed inventory, at fixed turbine output, coal consumption rate and air flow. Consequently, reducing the lower bed inventory is effective to decrease bed temperature but excessive reducing might increase bed temperature due to lack of circulating fluidized materials. Also, in case of the Yeosu Plant boiler using subbituminous coal as its primary fuel, its bed temperature change is highly affected by not only the amount of bed inventory, but also the boiler capacity and coal contents.