• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.28 no.2
• /
• pp.143-149
• /
• 2022

PCS needs to freely switch AC and DC to connect the battery, external AC loads and renewable energy in both directions for energy efficiency. Whenever converting happens, power loss inevitably occurs. Minimization of the power loss to save electricity and convert it for usage is a very critical function in PCS. PCS plays an important role in the ESS(Energy Storage System) but the importance of stabilizing semiconductors on PCB(Printed Circuit Board) should be empathized with a risk of failure such as a fire explosion. In this study, the temperature variation inside PCS was reviewed by cooling fan on top of PCS, and the vibration characteristics of PCS were analyzed during truck transportation for reliability of the product. In most cases, a cooling fan is mounted to control the inner temperature at the upper part of the PCS and components generating the heat placed on the internal aluminum cooling plate to apply the primary cooling and the secondary cooling system with inlet fans for the external air. Results of CFD showed slightly lack of circulating capacity but simulated temperatures were durable for components. The resonance points of PCS were various due to the complexity of components. Although they were less than 40 Hz which mostly occurs breakage, it was analyzed that the vibration displacement in the resonance frequency band was very insufficient. As a result of random-vibration simulation, the lower part was analyzed as the stress-concentrated point but no breakage was shown. The steel sheet could be stable for now, but for long-term domestic transportation, structural coupling may occur due to accumulation of fatigue strength. After the test completed, output voltage of the product had lost so that extra packaging such as bubble wrap should be considered.

• Journal of electromagnetic engineering and science
• /
• v.3 no.2
• /
• pp.140-146
• /
• 2003

In this paper, the design of a channel filter and its group-delay-and-amplitude equalizer is carried out for the Ka-band satellite transponder subsystem. The 8th order dual-mode filter is employed for high selectivity around the band-edges with an elliptic-integral function response and has an in-line configuration. The 2-pole, reflection-type, group-delay equalizer is designed and manufactured to reduce the group-delay and amplitude variation, which can be large for such a high order filter. It is noted that in both the filter and equalizer, adopting the dual-mode coupling mechanism leads to less mass and volume. Through measurement, the performance of the realized group-delay-equalized filter is shown to meet the equipment requirements and to be appropriate for the satellite input multiplexer.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10a
• /
• pp.243-246
• /
• 1996

Modular robot manipulator is a robotic system assembled from discrete joints and links into one of many possible manipulator configurations. This paper describes the design method of newly developed modular robot manipulator and the methodology of a task based reconfiguration of it. New locking mechanism is proposed and it provides quick coupling and decoupling. A parallel connection method is devised and it makes modular robot manipulator working well and the number of components on each module reduced. To automatically determine a sufficient or optimal arrangement of the modules for a given task, we also devise an algorithm that automatically generates forward and inverse manipulator kinematics, and we propose an algorithm which maps task specifications to the optimized manipulator configurations. Efficient genetic algorithms are generated and used to search for a optimal manipulator from task specifications. A few of design examples are shown.

• International Journal of High-Rise Buildings
• /
• v.9 no.2
• /
• pp.167-173
• /
• 2020

W-Project is 60-story mixed-use residential building complex project in Daegu, the third biggest city in South Korea. There are lots explorable items to be solved to secure structural safety and meet the serviceability requirements. This paper describes what kind of structural system is optimized based on the architectural requirements and structural components design and the grade of concrete strength altered on floors. The defining process of lateral resisting system of outrigger compared to the core ratio of typical plan is illustrated in detail.

• Journal of Computational Design and Engineering
• /
• v.3 no.3
• /
• pp.215-225
• /
• 2016

In recent years, the automotive industry has known a remarkable development in order to satisfy the customer requirements. In this paper, we will study one of the components of the automotive which is the twist beam. The study is focused on the multicriteria design of the automotive twist beam undergoing linear elastic deformation (Hooke's law). Indeed, for the design of this automotive part, there are some criteria to be considered as the rigidity (stiffness) and the resistance to fatigue. Those two criteria are known to be conflicting, therefore, our aim is to identify the Pareto front of this problem. To do this, we used a Normal Boundary Intersection (NBI) algorithm coupling with a radial basis function (RBF) metamodel in order to reduce the high calculation time needed for solving the multicriteria design problem. Otherwise, we used the free form deformation (FFD) technique for the generation of the 3D shapes of the automotive part studied during the optimization process.

• Journal of Institute of Control, Robotics and Systems
• /
• v.20 no.12
• /
• pp.1252-1258
• /
• 2014

ROS is based on a graph architecture where processing takes place in nodes. Nodes communicate together by passing messages through topics based on the publish/subscribe model. On the other hand, OPRoS components know each other and are tightly-coupled via port connections, and different coupling schemes make the interoperation between two platforms difficult. This paper describes an extension of OPRoS framework to support the interoperation with the ROS topic.

• Computational Structural Engineering
• /
• v.6 no.4
• /
• pp.73-82
• /
• 1993

Investigated in this paper is the effect of fluid-structure interaction between reactor internal components due to their immersion in a confining fluid on the dynamic responses. A non-linear mathematical model is developed for the dynamic analysis of the reactor internals, which includes lumped masses, stiffnesses and hydrodynamic couplings. The hydrodynamic mass matrix which characterizes the fluid-structure interaction is calculated. Also, the equations of motion containing hydrodynamic mass matrix are presented. The responses of the reactor internals due to seismic and pipe break excitations are obtained for the case of with- and without-hydrodynamic couplings and the different response characteristics are investigated.

• Journal of Environmental Impact Assessment
• /
• v.21 no.3
• /
• pp.461-468
• /
• 2012

In general, long-term changes of ecological factors take a pulse form in which they interact with other factors and go through a repeated increasing and decreasing cycle. The coupling of the two approaches the grid model and the box model in ecological modeling can lead to an in-depth understanding of the environment. The study analyzes temporal variations of major storages with an energy system model that formulizes effectively the relationships among nutrients, phytoplankton, and zooplankton in the Yellow Sea and the East China Sea. An increase of light intensity and standing stock of nutrient increase the magnitude and frequency of pulsing. Also, an immense reduction of nutrient concentration can cause extinction of the pulsing and bring about a steady state. It is concluded that the nutrient loads in freshwater discharge from the Yangtze affect the cycles of major ecological components as well as water quality variables and play an important role in the marine ecosystem.

• Korea-Australia Rheology Journal
• /
• v.12 no.2
• /
• pp.125-133
• /
• 2000

The present work is aimed at performing injection molding filling simulation of fiber suspension in polymer based matrix. The numerical simulation incorporates the coupling effect between the flow field and the fiber orientation state together with in-plane velocity gradient effect with recently proposed closure approximations. Predicted orientation components are compared with available experimental data of a film-gated strip and a center-gated disk. Predictions with IBOF closure approximation show excellent behaviors with regard to accuracy and numerical efficiency. However, predicted results seem to have consistent errors in comparison with experimental data. Diffusivity term which accounts for fiber-fiber interaction might have to be modified.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.4
• /
• pp.233-239
• /
• 2000

Investigation results are presented fur the shaft end displacements due to the elastic deformation of the casing and support in double suction centrifugal pump. Suction and discharge nozzles of the pump are subject to external piping loads and, in API 610, maximum values of their components are specified. This means that each nozzle can be subject to various combinations of loading conditions. Considering upper and lower criteria of each load, we must perform for the 4,096 load cases, and assign the direction and range of the loads. So, this paper develops an efficient procedure(Compliance Coefficient Method) to calculate the shaft end displacements(＠ coupling) to determine whether satisfying the pump's standard. Also, we analyzed the effects of the casing and support thickness on shaft end displacements.