• 유체기계공업학회:학술대회논문집
• /
• 2006.08a
• /
• pp.33-36
• /
• 2006

As the computing environment is rapidly improved, the interests of CFD are gradually focused on large-scale computation over complex geometry. Keeping pace with the trend, essential computational tools to obtain solutions of complex aerospace flow analysis and design problems are examined. An accurate and efficient flow analysis and design codes for large-scale aerospace problem are presented in this work. With regard to original numerical schemes for flow analysis, high-fidelity flux schemes such as RoeM, AUSMPW+ and higher order interpolation schemes such as MLP (Multi-dimensional Limiting Process) are presented. Concerning the grid representation method, a general-purpose basis code which can handle multi-block system and overset grid system simultaneously is constructed. In respect to design optimization, the importance of turbulent sensitivity is investigated. And design tools to predict highly turbulent flows and its sensitivity accurately by fully differentiating turbulent transport equations are presented. Especially, a new sensitivity analysis treatment and geometric representation method to resolve the basic flow characteristics are presented. Exploiting these tools, the capability of the proposed approach to handle complex aerospace simulation and design problems is tested by computing several flow analysis and design problems.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.10 no.1
• /
• pp.96-99
• /
• 2014

The aim of the study was to evaluate the water treatment of pressurized water reactor secondary side by the mixed amine of ammonia and ethanolamine, from the standpoint of corrosion control, as compared with all volatile treatment of ammonia. The pressurized water reactor systems have switched a secondary side pH control agent to minimize the corrosion in the moisture separator/reheater and feedwater heater systems and the transport of corrosion products into steam generator. As results of field test, pH was increased in the steam generator and the wet steam area of moisture separator/reheater and the concentration of Fe were decreased by more than 50% as compared with water treatment of ammonia.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1913-1919
• /
• 2007

Substantive provisions of the concept of an estimation and safety of complex technical systems are envisaged. New problems are assume orientation to use of the formalized methods of an estimation of residual resources of reliability of objects, and also development of other methodological base in creation of complex technical systems that is connected with detailed elaboration of attention to a safety at all stages of creation of systems: from designing until operation. In this connection existing large objects should be provided by the developed systems of engineering monitoring and diagnostics.

• Journal of the Semiconductor & Display Technology
• /
• v.20 no.1
• /
• pp.54-58
• /
• 2021

The RGO with controllable oxygen functional groups is a novel material as the active layer of resistive switching memory through a reduction process. We designed a nanoscale conductive channel induced by local oxygen ion diffusion in an Au / RGO+GQD / Al resistive switching memory structure. A strong electric field was locally generated around the Al metal channel generated in BIL, and the local formation of a direct conductive low-dimensional channel in the complex RGO graphene quantum dot region was confirmed. The resistive memory design of the complex RGO graphene quantum dot structure can be applied as an effective structure for charge transport, and it has been shown that the resistive switching mechanism based on the movement of oxygen and metal ions is a fundamental alternative to understanding and application of next-generation intelligent semiconductor systems.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.511-514
• /
• 2007

Gas hydrate has a unique property that can store a large volume of gas in water as a solid form. Even though investigations for natural gas storage technology have been carried out for several decades, there are still a lot of unsolved problems due to complex formation process, low formation speed, high energy consumption and so on. So, lots of experiments were conducted to overcome these weaknesses and to develop artificial NGH formation technology applicable to industrial-scale storage and commercial transport. In this study, some series of experiments were performed to analyze both stirred and unstirred system especially about the influences of several gas hydrate formation factors such as agitation speed, system temperature, SDS concentration, etc. As a result, optimum range of SDS concentration and temperature that could enhance the storage capacity and shorten the formation time were found. And it is obviously presented that SDS such a kind of surfactant promotes gas hydrate formation dramatically and the quantity of stored gas are proportional to agitation speed in stirred system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.10
• /
• pp.1317-1327
• /
• 2016

The baggage handling system (BHS) is one of the most complex system in the airport. A highly economical operating system is required to ensure its performance in consideration of its enormous cost on the extension. Furthermore, the inefficient operation deteriorates not only the system performance but the imbalance among the check-in counters because of a bottleneck on the conveyors downstream. The objective of this research is to improve the performance of both the BHS and the check-in area by efficiently controlling the flow in the merging area on the conveyors. Thus, we suggest a control logic of which the concept is borrowed from data networks. The simulation is used to analyze impacts of the conveyors bottleneck on the check-in area and optimize some parameters used in the suggested logic. We also discuss some observations from the simulation results into several aspects of performance measures.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.22 no.5
• /
• pp.216-223
• /
• 2023

As the technology and level of autonomous vehicles advance and they drive in more diverse road environments, an intuitive and efficient interaction system is needed to resolve and respond to the situations the vehicle faces. The development of driving technology from the perspective of autonomous driving has the ultimate goal of responding to situations involving humans or more. In particular, in complex road environments where mutual concessions must be made, the role of a system that can respond flexibly through efficient communication methods to understand each other's situation between vehicles or between pedestrians and vehicles is important. In order to resolve the status of the vehicle or the situation being faced, the provision and method of information must be intuitive and the efficient operation of an autonomous vehicle through interaction with intention is required. In this paper, we explain the vehicle structure and functions that can display information about the situation in which the autonomous vehicle driving in a living lab can drive stably and efficiently in a diverse and complex environment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.283-291
• /
• 2006

Recently, a logistics between south and north Korea is rising rapidly by increasing of economical exchange between two Korea and growth of Gaeseoung Industrial Complex. Considering this trend of economic cooperation between two Korea, in addition to a land transportation route it is necessary to secure various logistics and transportation route. A barge transport system which has merits such as a little initial investment and convenience of harbor loading/unloading has been also used to transport freight widely in the EU and USA. In this paper, firstly, a social and economical feasibility study is performed about a shipping route which is using barge transportation system between Incheon and Gaesung. And also we propose several candidate shipping route and investigate a technical feasibility on a realistic possibility of shipping service by some investigation activities. Finally, the optimized shipping route and barge transportation system are proposed in this paper.

• Journal of Environmental Science International
• /
• v.19 no.2
• /
• pp.137-148
• /
• 2010

This paper investigates the characteristics of turbulence schemes. Turbulence closures are fundamental for modeling the atmospheric diffusion, transport and dispersion in the boundary layer. In particular, in non-homogeneous conditions, a proper description of turbulent transport in planetary boundary layer is fundamental aspect. This study is based on the Regional Atmospheric Modeling System (RAMS) and combines four different turbulence schemes to assess if the different schemes have a impact on simulation results of vertical profiles. Two of these schemes are Isotropc Deformation scheme (I.Def) and Anisotropic deformation scheme (A.Def) that are simple local scheme based on Smagorinsky scheme. The other two are Mellor-Yamada scheme (MY2.5) and Deardorff TKE scheme (D.TKE) that are more complex non-local schemes that include a prognostic equation for turbulence kinetic energy. The simulated potential temperature, wind speed and mixing ratio are compared against radiosonde observations from the study region. MY2.5 shows consistently reasonable vertical profile and closet to observation. D.TKE shows good results under relatively strong synoptic condition especially, mixing ratio simulation. Validation results show that all schemes consistently underestimated wind speed and mixing ratio but, potential temperature was somewhat overestimated.

• The KIPS Transactions:PartD
• /
• v.11D no.2
• /
• pp.461-470
• /
• 2004

As the semiconductor industrials change 200㎜-sized semiconductor wafer production process to 300㎜-sized one, it requires to develop the software for monitoring and simulating the robot which transfers a 300㎜-sized semiconductor wafer. Because such a software don't run at standalone but communicate MCS(Material Control System) and Its subsystem a robot, its architecture is very complex. Therefore, in order to develop such a software systematically, we must utilize an object-oriented development methodology. UML. This paper presents an UML process application developing the software for monitoring and simulating the robot which transfers a semiconductor wafer on the production process.