• Applied Microscopy
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• v.46 no.1
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• pp.51-57
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• 2016

The histology and anatomy of the olfactory organ in Luciogobius guttatus was investigated using a light microscopy and scanning electron microscopy. The paired olfactory organs in the dorsal part of the snout are situated in between the upper lip and the eyes. They consist of two nostrils, one anterior and the other posterior openings, and a single olfactory cavity. The anterior nostril, an incurrent opening, forms a short tubular structure from the skin. The posterior nostril, an excurrent opening, forms a circular structure opened to the exterior. The distributional pattern of the sensory epithelium is a continuous type. The sensory epithelium with numerous-motile cilia is made up of receptor cells, supporting cells, basal cells, and mucous cells. In contrast, the non-sensory epithelium is comprised of stratified epithelial cells and two types of mucous cells, acidic and neutral cells. The cilia number of the receptor cell is in range of 3 to 4 units. Such results in L. guttatus may reflect its ecological habit and microhabitat in the tidal zone with a periodic tide.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.51-62
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• 2013

The importance of environmental water has been risen in terms of river ecosystem soundness with preventing stream flow depletion in rural area, while enlarging agricultural reservoir project is conducted under the 4 main river restoration project for supplying more water to 4 main rivers. The aim of this study was to estimate the amount of environmental water release and analyze the release pattern during non-irrigation season in enlarged agricultural reservoirs. The 4 reservoirs (Dansan, Samga, Geumbong, Changpyeong) located on the upper region of Nakdong river were simulated applying the operation rule which was determined by release criteria curves. The simulated results indicated that the more environmental water could be released than the spillway release and continuous release was achieved with smaller range of fluctuation. In case of Changpyeong reservoir, average 506.0 thousand $m^3$ environmental water could be released on Feb., and it was about twice as much as the spillway release before the enlargement, and also, the 18 thousand $m^3$/day environmental water could be supplied to a stream consistently after enlargement. From the results, it was expected that the additional environmental water release will improve stream water flow during dry season in terms of quantity and quality of water.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.315-325
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• 2015

Smart Car market has been experiencing continuous growth to drive leading companies in automotive and IT industries to focus on advancing related technologies. As the IT technologies fuse into automotive technologies, the patent litigation has been showing changes. One of the prominent changes in patent litigation pattern of Smart Car field is the increased activities of the Non-Practicing Entities (NPEs), whose main field has been the IT area. However, the automotive companies have been mainly focusing on preventing patent disputes against competitors through trend analysis, which caused them to become relatively vulnerable to the attacks from NPEs. In this study, we developed a methodology for monitoring and analyzing the activities of NPEs using network analysis tools to suggest effective strategies for manufacturing companies to fortify their ability to respond against unanticipated attacks. Our methodology, which is developed for the Smart Car field, can also be useful for other fields such as IT and electronics.

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.81-93
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• 2011

This research deals with the multi-modal continuous network design problem to resolve the transportation policy problems for constructing and operating transportation facilities with considering the mutual decision-making process between transportation operator and user in the multi-modal network. Particularly, in the consideration of changes in travel pattern between transport modes due to the changes in transportation policy, road network for passenger car and transit network for public transportation are considered together. In the development of network design model, more rational Stackelberg equilibrium(cooperative game) rather than more general Nash equilibrium(non-cooperative game) approach is used and sensitivity analysis considering transport mode is used. A multi-modal continuous network design model in this study is developed for the arbitrary continuous network design parameters(${\epsilon},\hat{\epsilon},p$) of transportation policy decisions. As examples of application and evaluation for these design parameters, the developed model is applied to calculate 1)the optimal capacity of road link in the road transport policy, 2)the optimal frequency of transit line in public transport policy and 3)the optimal modal split in transport modal share policy.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.57-62
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• 2012

The purpose of this paper is to find dangerous factors of a water purifier when water leaks due to inappropriate use and analyze the patterns of damaged parts in order to provide data for the examination of the cause of the problem. If the water purifier is inspected and managed by a non-specialist, when the FLC(Float Level Controller) at the top is inclined, water leakage may occur to the water purifier. The leaked water flows onto the cables and hoses and enters the thermostat terminal, heater, PCB, power supply connection connector, etc., becoming a dangerous factor that may cause a system failure, fire, etc. Due to the water that entered the input terminal, low noise and white smoke were generated at first. However, the flame gradually propagated due to the continuous inflow of moisture. It was found that when moisture reached the PCB, a carbonized conductive path was formed at the varistor terminal, input terminal, semiconductor device terminal, etc., and the flame became larger, which might result in a fire. From the metal microscope analysis of a damaged condenser terminal, it was found that the amorphous structure unique to copper cable disappeared, and voids, boundary surface and disorderly fine particles occurred. Also, in the case of the connector into which moisture penetrated, fusion and deformation occurred at the cable connection clips. The result of analysis of the power supply cable connector using a thermal image camera showed that most of the heat was generated from the cable connection clips and the temperature at the connection center was normal.

• Korean Journal of Agricultural Science
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• v.50 no.3
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• pp.331-347
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• 2023

The downstream submergence damages caused during the flood season in 2020, around the Yongdam-dam and five other sites, were analyzed using related dam management data. Hourly- and daily-data were collected from public national websites and to conduct various analyses, such as autocorrelation, partial-correlation, stationary test, trend test, Granger causality, Rescaled analysis, and principal statistical analysis, to find the cause of the catastrophic damages in 2020. The damage surrounding the Yongdam-dam in 2020 was confirmed to be caused by mis-management of the flood season water level. A similar pattern was found downstream of the Namgang- and Hapcheon-dams, however the damage caused via discharges from these dams in same year is uncertain. Conversely, a different pattern from that of the Yongdam-dam was seen in the areas downstream of Sumjingang- and Daecheongdams, in which the management of the flood season water level appeared appropriate and hence, the damages is assumed to have occurred via the increase in the absolute discharge amount from the dams and flood control capacity leakage of the downstream river. Because of the non-stationarity of the management data, we adapted the wavelet transform analysis to observe the behaviors of the dam management data in detail. Based on the results, an increasing trend in the discharge amount was observed from the dams after the year 2000, which may serve as a warning about similar trends in the future. Therefore, additional and continuous research on downstream safety against dam discharges is necessary.

• Journal of Korean Society of Steel Construction
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• v.18 no.3
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• pp.373-383
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• 2006

In a steel structural system, noncomposite form deck one-way slab is the plate element supported by four-edged steel beams with unequaled stiffness. However, design criterion has analyzed the one-way slab as the continuous beam. Because the end beams that support the one-way slab have elastic supports t hat cause different deflections according to the support conditions and locations, the bending moments corresponding to the support ic support effect is not considered in the design criterion. Accordingly, to conduct a reasonable estimation of approximate moment coefficients considering the unequaled elastic support conditions, this study analyzes and estimates various models with varia bles for the ratios of live load to dead load and pattern arangements of live loads and span lengths. The analytical methods considering the finite three-dimensional plate element, the two-dimensional elastic support and the infinite stifnes suport are performed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.331-338
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• 1994

The objective of this study is to obtain the basic data for investigating the potentiality of continuous utilization (first cutting in the late fall and regrowth yield in next spring) of forage rape seeded in fall. Non-structural carbohydrates(NSC) in leaves and roots of forage rape seeded on Oct. 3 were analyzed during a growth period. The greatest change in NSC content was observed between the wintering and the early spring period. The total content of soluble sugar in leaves and roots highly increased from the late fall(Nov. 7) to the wintering period (Feb. 4), and then rapidly decreased on the early regrow^ period(Mar. 31). The contents of fructose and glucose were relatively lower, and their quantitative change also was smaller than those of other sugars through entire growth period. The highest accumulation of sucrose occured hum the late fall to wintering period, and then greatly decreased in the early regrowth period. Sucrose content in roots was 2.3 times higher than that of leaves in wintering period. Starch was the largest pool of NSC and its content in leaves and roots showed a similar pattern with that of sucrose through entire growth period. Starch contents in leaves and roots were 38mg and 189mgl gDM in the late fall(Nov. 7), 187 and 497mg/gDM(Feb. 4) in the wintering period and 69 and 79mglgDM(Mar. 28) in the early regrowth period, respectively. The results clearly showed that the main reserve forms of NSC are starch and sucrose, and that they are hlghly stored in roots in overwintering forage rape.

• Steel and Composite Structures
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• v.37 no.6
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• pp.663-678
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• 2020

This paper proposes a novel topology optimization method generating multiple materials for external linear plane crack structures based on the combination of IsoGeometric Analysis (IGA) and eXtended Finite Element Method (X-FEM). A so-called eXtended IsoGeometric Analysis (X-IGA) is derived for a mechanical description of a strong discontinuity state's continuous boundaries through the inherited special properties of X-FEM. In X-IGA, control points and patches play the same role with nodes and sub-domains in the finite element method. While being similar to X-FEM, enrichment functions are added to finite element approximation without any mesh generation. The geometry of structures based on basic functions of Non-Uniform Rational B-Splines (NURBS) provides accurate and reliable results. Moreover, the basis function to define the geometry becomes a systematic p-refinement to control the field approximation order without altering the geometry or its parameterization. The accuracy of analytical solutions of X-IGA for the crack problem, which is superior to a conventional X-FEM, guarantees the reliability of the optimal multi-material retrofitting against external cracks through using topology optimization. Topology optimization is applied to the minimal compliance design of two-dimensional plane linear cracked structures retrofitted by multiple distinct materials to prevent the propagation of the present crack pattern. The alternating active-phase algorithm with optimality criteria-based algorithms is employed to update design variables of element densities. Numerical results under different lengths, positions, and angles of given cracks verify the proposed method's efficiency and feasibility in using X-IGA compared to a conventional X-FEM.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.3
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• pp.211-220
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• 2020

When domestic sewage and rainwater runoff are discharged into a single sewer pipe, it is called a "combined sewer system." The sewage design standards in Korea specify the flow velocity based only on the volume of rainfall; therefore, sedimentation occurs on non-rainy days owing to the reduced flow rate and velocity. This sedimentation reduces the discharge capacity, causes unpleasant odors, and exacerbates the problem of combined sewer overflow concentration. To address this problem, the amount of sewage on non-rainy days, not just the volume of rainfall, should also be considered. There are various theories on sedimentation in sewer movement. This study introduces a self-cleansing velocity based on tractive force theory. By applying a self-cleansing velocity equivalent to the critical shear stress of a sand particle, sedimentation can be reduced on non-rainy days. The amount of sewage changes according to the water use pattern of citizens. The design hourly maximum wastewater flow was considered as a representative value, and the velocity of this flow should be more than the self-cleansing velocity. This design method requires a steeper gradient than existing design criteria. Therefore, the existing sewer pipelines need to be improved and repaired accordingly. In this study, five types of improvement and repair methods that can maximize the use of existing pipelines and minimize the depth of excavation are proposed. The key technologies utilized are trenchless sewer rehabilitation and complex cross-section pipes. Trenchless sewer rehabilitation is a popular sewage repair method. However, it is complex because the cross-section pipes do not have a universal design and require continuous research and development. In an old metropolis with a combined sewer system, it is difficult to carry out excavation work; hence, the methods presented in this study may be useful in the future.