• International Journal of Automotive Technology
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• v.3 no.1
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• pp.27-32
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• 2002

Semi-active suspension systems are greatly expected to be in the mainstream of future controlled suspensions fur passenger cars. In this study, a continuous variable damper for a passenger car suspension is developed. It is controlled actively and exhibits high performance with light weight, low cost, and low energy consumption. To get fast response of the damper, reverse damping mechanism is adapted, and to get small pressure change rate after blow-off, a pilot controlled proportional valve is designed and analyzed. The reverse continuous variable damper is designed as a HS-SH damper which offers good body control with reduced transferred input force from tire, compared with any other type of suspension system. The damper structure is designed, so that rebound and compression damping force can be tuned independently, of which variable valve is placed externally. The rate of pressure change with respect to the flow rate after blow-offbecomes smooth when the fixed orifice size increases. Damping forces are measured with the change of the solenoid current at the different piston velocities to confirm the maximum hysteresis of 20N, linearity, and variance of damping farce. The damping farce variance is wide and continuous, and is controlled by the spoof opening, of which scheme is usually adapted in proportional valves. The reverse continuous variable damper developed in this study is expected to be utilized in the semi-active suspension systems in passenger cars after its performance and simplicity of the design is confirmed through real car test.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.21-30
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• 2005

In this paper, we propose lane detection and trackinB algerian using B-Snake as robust algorithm. One of chief virtues of Lane detection algorithm using B-Snake is that it is possible to specify a wider range of lane structure because B-Spline conform an arbitrary shape by control point set and that it doesn't use any camera parameter. Using a robust algorithm called CHVEP, we find the vanishing point, width of lane and mid-line of lane because of the perspective parallel line and then we can detect the both side of lane mark using B-snake. To demonstrate that this algorithm is robust against noise, shadow and illumination variations in road image, we tested this algorithm about various image divided by weather-fine, rainy and cloudy day. The percentage of correct lane detection is over 95$\%$.

• The Korean Journal of Food & Health Convergence
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• v.6 no.5
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• pp.19-25
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• 2020

The purpose of this study was to research and develop a step-type chemical liquid deodorizer including a liquid catalyst that can prevent civil complaints due to odor due to its excellent deodorizing performance. The main composition of chemical liquid deodorizer including liquid catalyst is cleaning deodorization, catalyst deodorization, chemical deodorization, water film plate, deodorization water circulation device, deodorization water injection device, catalyst management system, gas-liquid separation device, chemical supply device, deodorizer control panel, etc. It consists of a device. The air flow of the step-type liquid catalyst chemical liquid deodorizer is a technology that firstly removes basic odor substances, and the liquid catalyst installed in the subsequent process stably removes sulfur compounds, which are acidic odor substances, to discharge clean air. The efficiency of treating the complex odor of the prototype was 98.5% for the first and 99.6% for the second, achieving the target of 95%. The hydrogen sulfide treatment efficiency of the prototype was 100% for the first and 99.9% for the second, which achieved 95%, which was the target of the project. As a result, ammonia was removed by the reaction of ammonia and hydrogen sulfide.

• Journal of Aerospace System Engineering
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• v.13 no.5
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• pp.32-38
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• 2019

The flying wing configuration with high sweep angles and rounded leading edge represent a complex flow of structures by the leading edge vortex. For control of the tailless flying wing configuration with unstable directional stability, flaperon is used. In this study, we conducted numerical simulations for a non-slender flying wing configuration with a rounded leading edge and analyzed the effect of the sideslip angle and flaperon. Through aerodynamic coefficient analysis, it was found that the effect of AoS on lift and drag coefficient was minimal and the side force and moment coefficient were markedly influenced by AoS. As the sideslip angle increased, the pitch break, which is related to the pitching moment coefficient, was delayed. Through stability analysis, the directional and lateral static stability of the flying wing configuration were increased by flaperon. Also, the structure and behavior of the leading edge vortex were analyzed by observing the contour of the pressure coefficient and the skin friction line.

• Membrane Journal
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• v.29 no.2
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• pp.105-110
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• 2019

Porous membranes are widely used in industry for removing particulate matter. Unlike conventional porous membrane fabrication methods, the solution spreading phase separation method can form pores very simply. The first step is to wet the mesh with the support layer, then to let the polysulfone solution flow into a solvent without water. The solvent is readily vaporized and the polysulfone is made into a thin film. When the polysulfone solution is mixed with water to form pores, the pore size can be adjusted according to the concentration ratio of the polysulfone solution. The thickness of the membrane is easily controlled by the concentration of the solution. The porous separator has the formation of meshes intact and is very useful for forming a three-dimensional structure. The solution spreading phase separation method proposed in this study is characterized by its high cost competitiveness compared with conventional membranes due to its low production cost and easy process control.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.2
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• pp.29-43
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• 2023

It is necessary to grasp the characteristics of traffic flow passing through a specific road section and the topological structure of the road in advance in order to quickly prepare a movement management strategy in the event of a disaster or disaster. It is because it can be an essential basis for road managers to assess vulnerabilities by microscopic road units and then establish appropriate monitoring and management measures for disasters or disaster situations. Therefore, this study presented spatial density, time occupancy, and betweenness centrality index to evaluate vulnerabilities by road link in the city department and defined spatial-temporal and topological vulnerabilities by clustering analysis based on distance and density. From the results of this study, road administrators can manage vulnerabilities by characterizing each road link group. It is expected to be used as primary data for selecting priority control points and presenting optimal routes in the event of a disaster or disaster.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.71-79
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• 2023

Air ingress incidents are major safety accidents in very-high-temperature reactors (VHTRs). Air containing a high volume fraction of oxygen may cause severe oxidation of core components at the VHTR, especially for the significantly thin alloy tube wall in the intermediate heat exchanger (IHE). The research objects of this study are Inconel 617 and Incoloy 800H, two candidate alloys for IHE in VHTR. The air ingress accident scenario is simulated with high-temperature air flow at 950 ℃. A continuous oxide scale was formed on the surfaces of both the alloys after the experiment. Because the oxide scale of Inconel 617 has a loose structure, whereas that of Incoloy 800H is denser, Inconel 617 exhibited significantly more severe internal oxidation than Incoloy 800H. Further, Inconel 617 showed a significant decrease in ultimate tensile strength and plasticity after aging for 200 h, whereas Incoloy 800H maintained its tensile properties satisfactorily. Through control experiment under vacuum, we preliminarily concluded that serious internal oxidation is the primary reason for the decline in the tensile properties of Inconel 617.

• Analyses & Alternatives
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• v.2 no.2
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• pp.93-110
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• 2018

Due to its speciality, Johannesburg has drawn wide attention from the international academia, which the existing urban theory cannot easily explain. This paper focuses on the spatial pattern of Johannesburg, and finds that it is highly fragmented: first North-South Division due to apartheid and gold mining, secondly, the continuous sprawl due to population densification, and thirdly formation of city-region due to the fill-in spatial policy. The fragmented spatial pattern undermines the social integration and weakens the potential economic sustainability, which make the balanced multi-core spatial pattern inevitable under the influence of the international planning thought. The Johannesburg's spatial transformation comes not only from social integration, but also from the development vison of world-class status of an African city. In reality, since the collapse of apartheid, the municipal government has released series of strategic planning in different executive phase. These different plannings unanimously focus on the world class status although since 2008, the social inclusiveness is more emphasized. Thus, Johannesburg implements some spatial policies, as promoting the corridor of freedom, identifying the key nodes in the city then developing with high density, implementing the in-filling policy, managing the urban growth boundary, effectively preserving the natural system. However, the industrial structure in Johannesburg is already quite high-ended which cannot produce many jobs and also require much investment in advanced infrastructure. Thus, the strategic goals of world-class status of an African city and social inclusiveness which really need widely shared public services to some extent are in tension. After evaluation, we can see that spatial transformation is quite limited. Obviously spatial transformation largely depends on the social-economy. The population is still in flow. In this sense Johannesburg must energetically support the employment-based industry, effectively control the spatial sprawl and carry out institutional innovation which further incentive investment, gradually build an integrated regional governance. In general, how Johannesburg combines globalization and its own condition is still worth thinking in both theory and practice.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.3
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• pp.168-176
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• 2013

The aim of this study was to evaluate the acid neutralizing capacity and to observe surface changes of giomer in comparison with composite resin, when it comes in contact with an acidic solution. A packable giomer(Beautifil II) and a flowable giomer(Beautifil Flow F02) were used as experimental groups, while a packable composite resin($Filtek^{TM}$ Z-250) was used as control group. pH values were measured after mixing the specimens of the disc and powder types with a pH 2.0 hydrochloric acid solution, respectively. Also, in the case of powder type giomers used in the earlier experiment, their pH values were measured again after mixing them with a fresh acid solution. Moreover, surface structure changes of disc type specimens were observed by using a scanning electron microscopy(SEM). In the disc type test, the pH values of packable giomer were significantly increased after 24 hours(p < 0.05). In contrast, in the powder type test, the pH values of packable and flowable giomers were dramatically increased within 30 minutes. The pH value of packable giomer, in particular, was higer than that of flowable giomer(p < 0.05). In the repeated neutralizing test, the degree of pH variation was lower than that of the previous neutralizing test(p < 0.05). Erosive changes on the surface of packable giomer were observed to be more than those on composite resin and flowable giomer as well. In conclusion, giomer has a acid neutralizing capacity, when it comes in contact with an acidic solution. Especially, packable giomer with high filler content has a greater acid neutralizing capacity than flowable giomer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.6
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• pp.374-386
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• 2010

Recently, the theoretical and experimental research is being made actively in control character of waves of perforated-wall caisson breakwater like the slit caisson. This study showed that the character of reflection coefficient and the wave pressure acting on the front and inner of slit caisson were estimated in two and three dimensional numerical wave flume and compared each other. The numerical experiment was set and conducted by various cases as to a variety of wave steepness under 7 sec, 9 sec, 11sec and 13 sec period condition. In this study using a 2 and 3 dimensional numerical wave flume, it applied the Model for the immiscible two-phase flow based on the Naveir-Stokes Equations. This technique can easily reproduce a complicated physical phenomenon more than others and organize the program simply. According to the results of the experiment, the reflection coefficient was estimated high in short-period waves. However, 2-dimensional numerical experiment and 3-dimensional numerical experiment were the same in case of the long-period waves and high wave steepness. And to conclude in case of short-period waves the pressures were a relatively small difference between the two, but there was a big gap in longperiod waves and high wave steepness.