• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1998.10a
• /
• pp.153-158
• /
• 1998

In this paper, we present a design of optimal 2-DOF PID controller for control of gantry crane which has to control swing motion and trolley position. For tuning the parameter of 2-DOF PID controller, we used evolution strategy(ES). During operate the crane system in yard, the goal is transporting the load to a goal position as quick as possible without rope oscillation. The crane is generally operated by an expert operator, but recently an automatic control system with high speed and rapid transportation is required. However, we developed an optimal controller which has to control the crane system with disturbance.

• Rapid Communication in Photoscience
• /
• v.4 no.2
• /
• pp.29-30
• /
• 2015

Since the first report on long-term durable perovskite solar cell in 2012, a surge of interest in perovskite solar cell has been received due to its superb photovoltaic performance exceeding 20%. $MAPbI_3$ ($MA=CH_3NH_3$) perovskite film is able to be prepared simply by solution processesof either sequential two-step or single step procedure. Since $MAPbI_3$ shows balanced charge transport property with micrometer scale charge diffusion length, it can be applied to any kind of junction structures. Mostly studied structure is mesoscopic structure employing mesoporous oxide layer in perovskite film. Photovoltaic performance is primarilyin fluenced by the quality of perovskite film but interfaces are equally important. In this mini review, emergence and evolution of perovskite solar cell are described.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.10a
• /
• pp.207-210
• /
• 2004

The deformation behavior of copper during equal channel angular pressing (ECAP) was calculated using a three-dimensional version of a constitutive model based on the dislocation density evolution. Finite element simulations of the variation of the dislocation density and the dislocation cell size with the number of ECAP passes are reported. The calculated stress, strain and cell size are compared with the experimental data for Cu deformed by ECAP in a modified Route C regime. The results of FEM analysis were found to be in good agreement with the experiments. After a rapid initial decrease down to about 200 nm in the first ECAP pass, the average cell size was found to change little with further passes. Similarly, the strength increased steeply after the first pass, but tended to saturate with further pressings. The FEM simulations also showed strain non-uniformities and the dependence of the resulting strength on the location within the workpiece.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.47.1-47.1
• /
• 2013

Supersonic turbulence is believed to decay rapidly within a flow crossing time irrespective of the degree of magnetization. However, this consensus of decaying magnetohydrodynamic (MHD) turbulence relies on local isothermal simulations, which are unable to investigate the role of global magnetic fields and structures. Utilizing three-dimensional MHD simulations including interstellar cooling and heating, we investigate decaying MHD turbulence within cold neutral medium sheets embedded in warm neutral medium. Early evolution is consistent with previous studies characterized rapid decay of turbulence with the decaying time shorter than a flow crossing time and power-law temporal decay of turbulent kinetic energy with slope of -1. If initial magnetic fields are strong and perpendicular to the sheet, however long term evolutions of kinetic energy shows that a significant amount of turbulent energy still remains even after ten flow crossing times, and decaying rate is reduced as field strengths increase. We analyse power spectra of remaining turbulence to show that incompressible, in-plane motions dominate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.7
• /
• pp.571-580
• /
• 1998

The numerical model that can describe the ignition of pseudospark discharge using hybrid fluid-particle(Monte Carlo )method has been developed. This model consists of the fluid expression for transport of electrons and ions and Poisson's equation in the electric field. The fluid equation determines the spatiotemporal dependence of charged particle densities and the ionization source term is computed using the Monte carlo method. This model has been used to study the evolution of a discharge in Argon at 0.5 torr, with an applied voltage if 1kV. The evolution process of the discharge has been divided into four phases along the potential distribution : (1) Townsend discharge, (2) plasma formation, (3) onset of hollow cathode effect, (4) plasma expansion. From the numerical results, the physical mechanisms that lead to the rapid rise in current associated with the onset of pseudospark could be identified.

• Journal of Information Technology Services
• /
• v.7 no.1
• /
• pp.45-62
• /
• 2008

This review examines the rapid growth of qualitative and quantitative of telecommunication industry for past couple of years from customer's viewpoint. Most of the telecommunication products were positioned in the market by the businesses and government's support, but the entity of telecommunication products were never interpreted from the user's viewpoint. Even though, various kinds of telecommunication services have been actively discussed by businesses, government, and IT professionals, it has not been sufficiently discussed by the marketing academia where they need to focus a lot on customer's utility. For the purpose of providing an insight of the telecommunication service marketing strategy, this study looked over old and new directions of growth, failure and evolution of services by focusing on two main pillar of communication business, which is high-speed internet and mobile phone service. Additionally, the research explains and mentions the limit and trend of the telecommunication service marketing, and the future research task that needs to be solved.

• BMB Reports
• /
• v.52 no.8
• /
• pp.475-481
• /
• 2019

The evolution of genome editing technology based on CRISPR (clustered regularly interspaced short palindromic repeats) system has led to a paradigm shift in biological research. CRISPR/Cas9-guide RNA complexes enable rapid and efficient genome editing in mammalian cells. This system induces double-stranded DNA breaks (DSBs) at target sites and most DNA breakages induce mutations as small insertions or deletions (indels) by non-homologous end joining (NHEJ) repair pathway. However, for more precise correction as knock-in or replacement of DNA base pairs, using the homology-directed repair (HDR) pathway is essential. Until now, many trials have greatly enhanced knock-in or substitution efficiency by increasing HDR efficiency, or newly developed methods such as Base Editors (BEs). However, accuracy remains unsatisfactory. In this review, we summarize studies to overcome the limitations of HDR using the CRISPR system and discuss future direction.

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3808-3814
• /
• 2023

The thermal stability of nitric acid solutions after contact with non-irradiated and irradiated tributyl phosphate (TBP) and its solution in Isopar-M has been studied. It has been established that exothermic processes occur during heating due to the interaction of soluble radiolysis products and the decomposition of the extractant with nitric acid. Such processes can occur at temperatures below 100 ℃, but unlike a thermal explosion that occurs in seconds, they are longer in time and are accompanied by weak heat evolution. Their intensity depends on the composition of the extractant, the concentration of HNO₃, and the volume ratio of the organic and aqueous phases. The presence of extractant degradation products in raffinates does not pose a risk of a rapid evolution of gaseous products during evaporation, however, the presence of reducing agents can significantly increase the intensity of the exothermic decomposition of raffinates.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.32 no.E
• /
• pp.88-94
• /
• 1990

Several models physically based to predict the evolution of the snowpack have been proposed. Validity of these models for hourly estimation is, however, questionable, since they have been tested only on a daily basis. A computational model to predict the amount of snowpack on an hourly basis in terms of snowload from a set of meterological measurements was developed and investigated the rapid snowmelt conditions during Fohn events in the Takada plain.

• Journal of Korea Technology Innovation Society
• /
• v.7 no.1
• /
• pp.42-63
• /
• 2004

Recent trend of rapid growth in the basic research activities in East-Asian newly industrialized countries bring about the change in the world knowledge production structure. Particularly, Korea showed the changing patterns not only in the number of publication, but also in the aspect of structural change of basic research activities. The stylized facts of basic research activities in Korea can be summarized in three aspects; first, selective development patterns, second, reverse pattern of evolution, and finally, the rapid growth of basic research activities in major firms. This paper analyse the evolutionary patterns of basic research activities in empirical base and propose the policy implication for supporting basic research activity in newly industrializing countries.