• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1743-1746
• /
• 2003

Automated Container Terminals have been being developed over the world for many recent years and more and more countries get interested in it because the amount of containers exported or imported is steeply increasing. Existed Container Terminals were not designed to control this kind of heavily many containers. They would face many structural problems soon or later, although they have managed to do well until now. One of the most important things in developing Automated Container Terminal is to develop the equipment able to transfer the awfully many containers. Those are maybe Automated Transfer Cranes, Automated Guided Vehicles, and Automated Quay-Side Cranes. The word "Automated" means the equipment is operated without drivers and those equipments are able to work without taking any break. Through the researches on the existed transfer cranes, authors decided that the structure of existed transfer cranes is not proper to swift and fast transfer and it′s not impossible to handle so many containers in limited time. Therefore authors have been studying on the proper structure of the Automated Container Crane for past several years and a new type of transfer crane has been developed. Design concepts and control methods of a new crane will be introduced in this paper.

• Journal of The Korean Astronomical Society
• /
• v.48 no.1
• /
• pp.67-73
• /
• 2015

We present a novel method to implement time-delayed propagation of radiation fields in cosmological radiative transfer simulations. Time-delayed propagation of radiation fields requires construction of retarded-time fields by tracking the location and lifetime of radiation sources along the corresponding light-cones. Cosmological radiative transfer simulations have, until now, ignored this "light-cone effect" or implemented ray-tracing methods that are computationally demanding. We show that radiative transfer calculation of the time-delayed fields can be easily achieved in numerical simulations when periodic boundary conditions are used, by calculating the time-discretized retarded-time Green's function using the Fast Fourier Transform (FFT) method and convolving it with the source distribution. We also present a direct application of this method to the long-range radiation field of Lyman-Werner band photons, which is important in the high-redshift astrophysics with first stars.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.155-156
• /
• 2015

Recently, electricity consumption has rapidly increased along with economic growth. The operating strategy using emergency generator is aimed, to resolve a demand response management. For strategy of peak shedding using emergency generator, it is essential to introduce the fast transfer switching device. One of the most effective solutions is to use a static transfer switch (STS) based on thyristor. However, the characteristic of natural commutated SCR thyristor should anticipate short duration voltage sag. STS system thus requires more than a quarter cycle to successfully complete transfer process. This paper proposes the operation scheme of the STS system using the forced-commutation technique to mitigate instantaneous voltage sag during peak transfer process. Proposed STS system improved turn-off characteristic thus accomplishes the peak load shedding satisfied power quality. Performance of the proposed STS system is evaluated using electromagnetic transient program (EMTP) to confirm the effectiveness.

• Journal of KSNVE
• /
• v.10 no.5
• /
• pp.769-774
• /
• 2000

The purpose of the work is to present successful applications of a modified wavelet shrinkage method for the accurate and fast estimation of a transfer function. Although the experimental process of determining a transfer function introduces not only Gaussian but also non-Gaussian noises, most existing estimation methods are based only on a Gaussian noise model. To overcome this limitation, we propose to employ a modified wavelet shrinkage method in which L1 -based median filtering and L2 -based wavelet shrinkage are applied repeatedly. The underlying theory behind this approach is briefly explained and the superior performance of this modified wavelet shrinkage technique is demonstrated by a numerical example.

• Bulletin of the Korean Chemical Society
• /
• v.13 no.2
• /
• pp.140-145
• /
• 1992

The excited state intramolecular proton transfer and physical properties of 7-hydroxyquinoline are studied in various solutions and heterogeneous systems by measuring steady state and time-resolved fluorescence, reflection and NMR spectra. Proton transfer is observed only in protic solvents owing to its requirement of hydrogen-bonded solvent bridge for proton relay transfer. The activation energies of the proton transfer are 2.3 and 5.4 kJ/mol in $CH_3OH$ and in $CH_3OD$, respectively. Dimers of normal molecules are stable in microcrystalline powder form and undergo an extremely fast concerted double proton transfer upon absorption of a photon, consequently forming dimers of tautomer molecules. In the supercage of zeolite NaY, its tautomeric form is stable in the ground state and does not show any proton transfer.

• Nuclear Engineering and Technology
• /
• v.54 no.11
• /
• pp.4125-4133
• /
• 2022

KAERI (Korea Atomic Energy Research Institute) developed the conceptual design of PGSFR (Prototype Gen-IV Sodium Cooled Fast Reactor) and Burner Reactor. Since the reactor characteristics of the PGSFR and Burner Reactor are different, the shape, size and the arrangement of the main components in the reactors must be different. Therefore, the conceptual design for the fuel handling and transfer systems needs to be performed coinciding with the structure of the reactor. Especially, because a redan structure dividing hot and cold pool is installed in the reactor vessel, the conceptual design of the fuel handling and transfer system largely changes depending on the location of the redan structure. Various elements of the conceptual design and an integral arrangement for the fuel handling and transfer system were arranged according to the characteristics, sizes and shapes of the reactors. In this paper, the conceptual designs of the fuel handling and transfer system for PGSFR and Burner Reactor are described. Especially, an A-frame method is selected as the fuel handling and transfer system for the Burner Reactor, considering the layout of the internal structure. The tilt angle, diameter and length of A-frame is determined and the strength evaluation of the A-frame is performed.

• Nuclear Engineering and Technology
• /
• v.52 no.4
• /
• pp.708-720
• /
• 2020

Core-wide temperature distribution in sodium-cooled fast reactor plays a key role in its decay heat removal process, however the prediction for temperature distribution is quite complex due to the conjugate heat transfer between the assembly flow and the inter-wrapper flow. Hybrid medium model has been proposed for conjugate heat transfer modeling in the core. The core is modeled with a Realistic modeled inter-wrapper flow and hybrid medium modeled assembly flow. To validate present model, simulations for a three-assembly model were performed with Realistic modeling, traditional porous medium model and hybrid medium model, respectively. The influences of Uniform/Non-Uniform power distribution among assemblies and the Peclet number within the assembly flow have been considered. Compared to traditional porous medium model, present model shows a better agreement with in Realistic modeling prediction of the temperature distribution and the radial heat transfer between the inter-wrapper flow and the assembly flow.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.196-199
• /
• 2009

The most important thing is to analyze the Fast Cook Off problem of the solid motor case exposed to direct flame is a heat transfer analysis. Heat causes degradation and ignition of the propellant. To archive an acceptable reaction level in Fast Cook Off, the rocket motor case generally must fail structurally prior to propellant ignition. We investigate the responses of the solid motor case exposed to Fast Cook Off by using finite element method for the thermal analysis.

• Nuclear Engineering and Technology
• /
• v.55 no.7
• /
• pp.2474-2482
• /
• 2023

The development of fast reactors with complex designs and operation status requires more accurate and effective simulation. The Monte-Carlo method can generate multi-group cross-sections in arbitrary geometry without approximation on resonances treatment and leads to good results in combination with diffusion codes. However, in previous studies, the coupling of Monte-Carlo generated multi-group cross-sections (MC-MGXS) and transport solvers has shown relatively large biases in fast reactor problems. In this paper, the main contribution to the biases is proved to be the neglect of the angle-dependence of the total cross-sections. The flux-moment homogenization technique (MHT) is proposed to take into account this dependence. In this method, the angular dependence is attributed to the transfer cross-sections, keeping an independent form for the total sections. For the MET-1000 benchmark, the multi-group transport simulation results with MC-MGXS generated with MHT are improved by 700 pcm and an additional 120 pcm with higher order scattering. The factors that cause the residual bias are discussed. The core power distribution bias is also significantly reduced when MHT is used. It proves that the MCMGXS with MHT can be applicable with transport solvers in fast reactor analysis.

• Journal of Industrial Technology
• /
• v.27 no.B
• /
• pp.235-243
• /
• 2007

Sensor network is used to obtain sensing data in various area. The interval to sense the events depends on the type of target application and the amounts of data generated by sensor nodes are not constant. Many applications exploit long sensing interval to enhance the life time of network but there are specific applications that requires very short interval to obtain fine-grained, high-precision sensing data. If the number of nodes in the network is increased and the interval to sense data is shortened, the amounts of generated data are greatly increased and this leads to increased amount of packets to transfer to the network. To transfer large amount of packets fast, it is necessary that the delay between successive packet transmissions should be minimized as possible. In Sensor network, since the Operating Systems are worked on the event driven, the Timer Event is used to transfer packets successively. However, since the transferring time of packet completely is varies very much, it is very hard to set appropriate interval. The longer the interval, the higher the delay and the shorter the delay, the larger the fail of transfer request. In this paper, we propose ESTEO which reduces the delay between successive packet transmissions by using SendDone Event which informs that a packet transmission has been completed.In ESTEO, the delay between successive packet transmissions is shortened very much since the transmission of next packet starts at the time when the transmission of previous packet has completed, irrespective of the transmission timee. Therefore ESTEO could provide high packet transmission rate given large amount of packets.