• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.141-142
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• 2007

In recent years, the rate of mean sea level rise is increasing rapidly from the phenomena of global warming, together with the increasing trend of the storm scale. The issue of sea level rise is multifaceted and produces a range of environmental problems. Especially, high tides and the tidal currents become higher, and wave base increases, so the energy received at the coastal boundary may increase. This brings that many coastal environments go into disequilibrium, such as damages to the structures, erosion, and deposition Similarly it was known that the problems of nearshore processes and damage of berth and counter facilities during storm period had appeared at the small fishery port. Here we try to analyze the impact of the rearrangement of counter facilities and berth layout adopted for tranquility of its'inner harbor. Because this harbor is being connected to channel and open sea, the rearrangement of the structures might affect to the current speed and direction and wave height, so do to the sea bottom undulation. Therefore, we made model test for the several layouts of the berth and breakwater in this area.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.31-38
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• 2003

Among mitigation techniques for electric and magnetic field (EMF) from an overhead transmission line a passive loop is a way that can be cheap and easily installed on the existing towers and have a satisfactory effect as well. However current induced in the passive loop causes transmission power loss and the phase imbalance increases since geometrical asymmetry of the transmission lines becomes larger. So in order to evaluate the power loss and the phase imbalance due to a passive loop, this paper represent a 345[kV] 1-circuit flat type transmission line as asymmetrical 3-phase distributed parameter line model where the effect of a passive loop is embedded in the line parameters, and then formulates differential equations. By solving these equations voltages and currents of each phase at receiving end become known. We find out that power losses occur differently at each phase and positive sequence component decreases at receiving end while negative sequence component increase. In general phase imbalance due to a passive loop is slight, but it increases in proportional to the induced current and length of section where the passive loop is installed. Thus the phase imbalance should be included in terms of cost for introducing a passive loop.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.5
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• pp.141-150
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• 2014

In recent years, because of the development of ubiquitous technology in healthcare research is actively progress. Especially, healthcare service area is change to home for the elderly or patients from hospital. The technology to identify residents in a home is crucial for smart home application services. However, existing researches for resident identification have several problems. In this case, residents are needed to attach of various sensors on their body. Also relating private life, it is difficult to apply to resident's environment. In this paper, we used constraint-free sensor and unconscious sensor to solve these problems and we limited using of sensor and indoor environment in the way of working economical price systems. The way of multi-resident identification using only these limited sensors, we selected elements of personal identifications and suggested the methods in giving the weight to apply these elements to systems. And we designed the SABA mechanism to tract their location and identify the residents. It mechanism can distinguish residents through the sensors located each space and can finally identify them by using the records of their behaviors occurred before. And we applied the mechanism designed for applications to approve this location tracking system. We verified to the location tracking system performance according to the scenario.

• ALGAE
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• v.19 no.4
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• pp.293-301
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• 2004

A chain-forming toxic din flagellate, Gymnodinium catenatum (Graham) was known as a paralytic toxin-producer among Gymnodinoid group. In the study, the effects of water temperature, salinity and irradiance on the growth of G. catenatum isolated from Yeosuhae Bay, Korea were investigated. Water temperature range in which G. catenatum showed specific growth rate higher than 0.3 day$^{-1}$ were above about 18${^{\circ}C}$. However, salinity did not have such an effect on growth of G. catenatum. The maximum growth rate (0.5 day$^{-1}$) was obtained at 25${^{\circ}C}$ and 30 psu. The specific growth rate (u) expressed as a polynomial equation as functions of temperature (T; ${^{\circ}C}$) and salinity (S; psu) was $\mu$ = 0.005·T$^2$ - 0.0001164 T$^3$ - 0.063-S + 0.005-S$^2$ - 0.00007608-S$^3$ - 0.003-T-S + 0.00005308-T$^2$-S. Thus, in aspects of water temperature and salinity, the species may be expected to survive in most Korean coastal waters from early summer to autumn. The irradiance-growth curve was described as = 0.16 (I - 10.4)/(1 + 21.8) at 18${^{\circ}C}$ and 30 psu, indicating a half-saturation (Ks) photon flux density (PFD) of 42.6$\mu$mol m$^{-2}s^{-1}$ and compensation PFD (I$_0$) of 10.4$\mu$mol m$^{-2}s^{-1}$. These characteristic responses to irradiance suggest that G. catenatum can reside at the sub-surface.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.67-81
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• 2015

A FORTRAN program was developed to determine the optimal locations of multiple recharge wells in an aquifer with different arrangements of pumping wells. The simulated annealing algorithm was used to find optimal locations of two recharge wells which satisfied three objective functions. The model results show that locating two injection wells inside the cluster of pumping wells is efficient if the recovery rate only was taken into account. In contrast, placing injection wells to the side of the cluster is desirable if the simulation considers aggregate objective function. Therefore, installing an injection well on each side of the cluster seems to yield the maximum recovery rates for the existing pumping wells, and it yields similar increases in pumping rate for all wells in the cluster. The locations of recharge wells can be arranged in numerous configurations, because there are multiple near-optimal local minima or maxima. These results indicate that the simulated annealing can yield effective evaluations of the optimal locations of multiple recharge wells. In addition, the suggested aggregate objective function can be utilized as an appropriate multi-objective optimization.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.13-20
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• 2017

High-rise building shapes are changing from orthogonal to irregular form and the current trend is to arrange members in geometric grid-patterns at the perimeter of buildings. This study proposes a simple model for the preliminary design of a hexagrid high-rise building. The size of the cross section is set to be different at each module and hexagrid unit, which is different from the previous studies in which all hexagrid members were the same. To examine the effect of hexagrid size on structural performance, 60-story hexagrid buildings with 1-, 2- and 4-story high modules are designed and analyzed. Maximum lateral displacement, steel tonnage, load carrying percentage of perimeter frame and combined strength ratio are compared for 15 buildings. As the lateral load carrying capacity of hexagrid structure was inferior to a diagrid structural system, proper lateral stiffness should be allocated to the core frame in a hexagrid structure. The best ratio of flexural to shear deformation was 4 and larger unit size was better in considering constructional cost and structural efficiency. As the maximum lateral displacements of the buildings were within 84%~108% of the limit, the proposed method seems to be applicable to preliminary design of hexagrid buildings.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.184-191
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• 2011

Preliminary design of a mooring system for a floating wave energy converter(WEC) is performed. A mooring line is designed to consist of two parts; the one is a chain in heavy weight laid on the seabed and linked to an anchor on the seabed and the other is a light weight chain suspended at a floater. A high weight chain laid on the seabed can contribute to mitigate dynamic energy propagated from top oscillation and decrease anchor weight and volume. Through a low weight chain suspended between a floater and seabed the WEC's function to produce energy from wave can be affected in minimum by the motion of a chain. The static and dynamic analyses for the designed mooring system were carried out to evaluate WEC system's safety. The present study shows that the designed gravity anchor moves horizontally due to the tension exerted on the anchor in the severe ocean environmental condition. The present mooring system should be redesigned to satisfy the safety requirements. The present study will be useful to predict the safety of the mooring system under ocean environment.

• Journal of KIISE:Software and Applications
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• v.37 no.2
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• pp.104-109
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• 2010

The lighting reflection is a common problem in image analysis and causes the many difficulties to extract distinct features in related fields. Furthermore, the problem grows in the rainy night. In this paper, we aim to remove light reflection effects and reconstruct a road surface without lighting reflections in order to extract distinct features. The proposed method utilizes a 3D analysis based on a multiple geometry using captured images, with which we can combine each reflected areas; that is, we can remove lighting reflection effects and reconstruct the surface. At first, the regions of lighting sources and reflected surfaces are extracted by local maxima based on vertically projected intensity-histograms. After that, a fundamental matrix and homography matrix among multiple images are calculated by corresponding points in each image. Finally, we combine each surface by selecting minimum value among multiple images and replace it on a target image. The proposed method can reduces lighting reflection effects and the property on the surface is not lost. While the experimental results with collected data shows plausible performance comparing to the speed, reflection-overlapping areas which can not be reconstructed remain in the result. In order to solve this problem, a new reflection model needs to be constructed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.302-309
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• 2017

The influence of the pile diameter, center to center pile spacing, internal friction angle of embankment soil, and height of embankment on the arching efficacy of the embankment pile was investigated. The arching efficacy, which was derived by the arch model developed in the embankment soil was calculated using two methods, one that considers crown failure of the arch and the other that considers load on the pile cap and critical relative spacing ratio for which the arching efficacy calculated by the two methods are the same. According to the computed results in this study, the arching efficacy calculated from a consideration of the load on pile cap governs when the relative spacing ratio becomes smaller and that calculated from the theory of crown failure governs when the relative spacing ratio becomes larger. The critical relative spacing ratio below which the arching efficacy calculated from a consideration of the load on pile cap governs the design decreases with increasing value, which is defined by the ratio of the pile diameter to the pile center to center spacing. Critical relative spacing ratios, which correspond to the values of 0.5 and 0.2 were 0.35 and 0.85, respectively. Considering the computed results, the critical relative spacing ratio decreases with increasing Rankine passive earth pressure coefficient and critical relative spacing ratios, which correspond to values of 5 and 2, were 0.23 and 0.85, respectively. The arching efficacy, which corresponds to the area ratio of 9%, was 54% and the one that corresponds to the value of 3 was 61%; the critical relative spacing ratios, which correspond to those arching efficacies, were greater than 0.5.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.236-237
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• 2017

In this research, experimental seakeeping results of Warped hull form 2 on the regular waves were compared with numerical results of strip method and CFD. In case of ship's speed, there are 3 cases (3.4m/s, 4.6m/s, 5.75m/s) for numerical simulation, and they are belong to semi-planing and planing condition. Consequently, in case of strip method, it is shown that the resonance phenomena occurred from around ${\lambda}/L_{OA}=2$ to 4 and RAO value were significantly higher than that of other. this is different from experimental results. In case of CFD, overall trends were similar with experimental values except there are somewhat excessive RAO values around ${\lambda}/L_{OA}=0.5$ to 2.5. these phenomena is confirmed that it became larger as the ship's speed increased, and it was considered that the error occurred because the number of mesh in vertical direction of wave height at ${\lambda}/L_{OA}=0.5$ to 2.5 were relatively less than those of wave height at ${\lambda}/L_{OA}=2.5$ to 5.2.