• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.115-126
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• 2009

Many electric poles in the softground have been collapsed due to external load such as typhoon wind load. In this study, the location, numbers and depths of acnchor blocks as well as depth of poles were varied to find horizontal displacement of poles through pull-out tests. The 10 types of tests were performed, and lateral displacements showed differences depending on location, numbers and depth of poles. The bending is generated in the upper part at the initial load, but it moved to central part as load increased. The maximum horizontal displacement decreased to 1/1.6 at -0.5[m] depth of anchor block and 1.3[m] additional laying depth of poles into ground. Two anchor blocks of poles are better than one acnchor block system, but one anchor block system is recommended because difference of displacement is not too large, and constructibilty is bad due to increase of excavation for anchor blocks.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.226-236
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• 1997

The results obtained by elasto-plastic analysis method about the displacement, deformation and stability on the soft ground excavation using sheet pile were summarized as follows ; 1. In the case of strut 1 step, the maximum wall displacement value in the first and the second excavation was small, but it increase remarkably after the third excavation and when the excavation depth was 8m, the point of maximum wall displacement was shown 0.75H~0.8H. 2. The value of safety factor(Fs) was increased with increasing of the penetration depth of sheet pile, cohesion and internal friction angle of ground. Safety factor was mostly effected by penetration depth of sheet pile and more effected by cohesion than internal friction angle of ground. 3. Since the deformation of sheet pile of this ground from the results of analysis and measurement increased remarkabaly after 6m excavation depth, it was desirable that the point of strut installation was GL-6m. 4. Safe excavation depth on ground by analysis considered penetration depth, cohesion and internal friction was shown at the table 3.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.1-11
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• 2008

The purpose of this study is to present the design guideline for an effective application of light shelf in office building. For this, the computer simulation using Daylighting System of 3Ds Studio Max was performed, and the optimal values related to design factors such as a depth, a surface reflectance and a installation angle of light shelf were obtained. Then daylighting performance of light shelf using the optimal values was analyzed, and the simulation results show that the installation of the optimal light shelf can improve a indoor lighting environment in office building.

• Polymer(Korea)
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• v.35 no.3
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• pp.203-209
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• 2011

Two smooth and textured surfaced HDPE geomembranes (GMs) were cut into dumbbell shape and notched where depth of the notch produced a ligament thickness of 10% to 90% of the nominal thickness with the specimen at 10% interval. A series of laboratory simulation test for installation damage were carried out at different loading cycles on HDPE GMs in accordance with ISO 10722 test method and the effect of number of loading cycle on installation damage was compared. It was found that yield stress and elongation at yield point decreased gradually as the notch depth was increased. Both installation damaged and notched, GMs were used to understand stress crack behavior and this behavior was observed through NCTL test at $50{\pm}1^{\circ}C$ at different yield stresses immerging in pH 4 and pH 12 buffer solutions. Over 35% tensile load, GMs became vulnerable to stress cracking. Both damaged and notched GMs showed the same trend. Especially, notched GMs showed less strength than installation damaged GMs at every stress cracking test condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.85-94
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• 2015

Recently, research on the smart grid that combines ICT(Information & Communication technology) to the power system has been actively progressed. If the occupancy of the EV(Electric vehicle) is increased. the V2G(Vehicle to grid) system is available which constitutes the micro-grid through battery of EV. V2G system performs load leveling and efficient energy consumption by battery operation considering load condition. But, if the battery is used only depending on the electricity rates, it doses not consider the life of the battery. The ACC(Achievable cycle) and the total transferable energy of battery varies corresponding to the selected DOD(Depth of discharge). In this paper, the optimal DOD selection method of V2G system considering battery wear cost and average driving distance of EV. Also, the total revenue prediction of various nation is presented considering the actual electricity costs per hour.

• International Journal of Highway Engineering
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• v.20 no.4
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• pp.7-13
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• 2018

PURPOSES : In order to apply high-speed weigh-in-motion (HS WIM) systems to asphalt pavement, three high-durability asphalt concrete mixtures installed with a WIM epoxy are evaluated. METHODS : In this study, dynamic stability, number of loading repetitions to reach the rut depth of 1 mm, and rut depth measurements of three asphalt mixtures at $60^{\circ}C$ were compared using an Asphalt Pavement Analyzer (APA). Laboratory-fabricated material and field core samples were prepared and tested according to KS F2374. RESULTS : Through the laboratory tests, it was found that all three modified asphalt mixtures (stone-mastic, porous, and semi-rigid) with WIM epoxy showed favorable permanent deformation results and passed the dynamic stability criterion of 3000 loading repetitions per 1 mm. In addition, it was confirmed that the modified SMA mixtures cored from the field construction yields satisfactory rutting testing results using the APA. Finally, the epoxy used for the HS WIM installation shows good adhesion with the three asphalt mixtures and permanent deformation resistance.

• Korean Journal of Ecology and Environment
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• v.36 no.4 s.105
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• pp.467-472
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• 2003

In this study, an algal fence was developed and applied to reduce the input of algal scum into the water intake facility. The effectiveness of vertical algal fences(overlapped three types of meshes, (312 ${\mu}m$ ${\times}$ 375 ${\mu}m$, 390 ${\mu}m$ ${\times}$ 450 ${\mu}m$, and 0,7 cm ${\times}$ 1cm; vertical depth, 1.5 m; length of fence, about 120 m)) was experimentally tested at a water intake facility (Mulgum, lower Nakdong River). The application of the fence resulted in the statistically significant difference of algal biomass between inside and outside of the fence. According to ANOVA test, chi. a concentration in Day-1showed large difference at each depth of 0, 1, 2 m (0.001> p at each depth, n = 16 respectively). Especially large difference was observed at 0 and 1 m depth. However, the fence was only effective for a short period and its efficiency declined by Day-5after the installation. When better maintenance options for the fence are prepared, e.g. mechanical installation and periodic backwashing of the fence, the performance of algal fence may be sustained. In addition, reliable models for bloom prediction are required to provide an advanced indication of the optimal timing for the installation so that effective operation would be achieved.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.662-669
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• 2018

Recently, the installation of submarine power cables is under consideration due to the increase of electric power usage and the development of the offshore wind farm in island areas, including Jeju. In order to protect power cables installed on the seabed, it is necessary to calculate the burial depth based on the characteristics of anchoring, dragging and fishing, etc. However, there is no design standard related to the size of target ships to protect the cables in Korea. In this study, we analyzed the design standards for the protection of domestic submarine pipelines similar to submarine cables, and developed the risk matrix based on the classification by emergency anchoring considering the installation environment, then designed the size of target ships according to the cumulative function scale by ship size sailing through the sea concerned. Also, we linked marine accident conditions, such as anchoring, dragging, etc. and the environmental conditions such as current, sea-area depth of installation etc. to the criteria of the protection of submarine cable, and examined the size of specific target ships by dividing the operating environment of ships into harbor, coastal and short sea. To confirm the adequacy and availability of the size of target ships, we verified this result by applying to No. 3 submarine power cables, which is to be installed in the section from Wando to Jeju Island. This result is expected to influence in the development of a protection system for submarine cables and pipelines as well as the selection of anchor weight according to the determination of burial depth.

• Journal of Korea Water Resources Association
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• v.39 no.7 s.168
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• pp.583-592
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• 2006

There has been debated on the fact that a scour hole produced by the construction of a groyne has environmental benefits such as provision of diverse underwater habitats and shelter for fish in the event of flooding. Therefore researches are focusing on the scour field around the groyne area beyond the existing safety issues. The scour area on aquatic habitats would format many form on groyne conditions so that the analysis of scour area is strongly required. This study conducted the experiments on permeability and installation angle of groyne and suggested the data for groyne selection in environmental point as analyzing scour area. The physical modeling was performed in different permeability (0%, 20%, 40%, 60%, 80%) and installation angle of groyne ($60^{\circ},\;90^{\circ},\;120^{\circ}$). As the result of the study, scour area and scour depth at maximum scour condition was revealed for each case and suggested the differences according to experiment conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.127-134
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• 2024

With the growth of offshore wind power generation market, the corresponding installation vessel market is also growing. It is anticipated that approximately 100 installation vessels will be required in the of shore wind power generation market by 2030. With a price range of 300 to 400 billion Korean won per vessel, this represents a high-value market compared to merchant vessels. Particularly, the demand for large installation vessels with a capacity of 11 MW or more is increasing. The rapid growth of the offshore wind power generation market in the Asia-Pacific region, centered around China, has led to several discussions on orders for operational installation vessels in this region. The seabed geology in the Asia-Pacific region is dominated by clay layers with low bearing capacity. Owing to these characteristics, during vessel operations, significant spudcan and leg penetration depths occur as the installation vessel rises and descends above the water surface. In this study, using penetration variables ranging from 3 to 21 m, the unique vibration period, structural safety of the legs, and conductivity safety index were assessed based on penetration depths. As the penetration depth increases, the natural vibration period and the moment length of the leg become shorter, increasing the margin of structural strength. It is safe against overturning moment at all angles of incidence, and the maximum value occurs at 270 degrees. The conditions reviewed through this study can be used as crucial data to determine the operation of the legs according to the penetration depth when developing operating procedures for WTIV in soft soil. In conclusion, accurately determining the safety of the leg structure according to the penetration depth is directly related to the safety of the WTIV.