• Journal of Korea Technology Innovation Society
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• v.14 no.3
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• pp.516-551
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• 2011

This study analysed the institutional evolution of Korea's international cooperation of science and technology (S&T) from the viewpoint of the historical institutionalism. For this, it examined Korea's institutions for international S&T cooperation by dividing the whole period from the Korean war to the present into five sub-periods; period of technology aids, technology transfer, mutual cooperation, expanded cooperation, and highly sophisticated cooperation, respectively. It, then, reviewed the evolving process and characteristics of each period. In this study, the structure (environment), the actor (government), the institution of higher rank (science & technology policy) were considered as variables influencing upon the institutions of the international S&T cooperation. Upon this assumption, this study analysed how and through what evolutionary process the international S&T cooperation institutions have evolved so far. This study obtained the following conclusions; First, the study confirmed the existence of the "institutional layering" in the institutions of the international S&T cooperation in Korea. The momentums for the change of the institutions of the international S&T cooperation stem from international environment and domestic economic environment. They influence upon economic policy, industrial policy, and S&T policy, which, together with the actor (the government), again brings about the institutional evolution of the international S&T cooperation. Second, the institutional evolution of the international S&T cooperation is taking place gradually. As mentioned above, the momentums for the change of the institutions of the international S&T cooperation originate from international and domestic macro environment. These momentums do not directly influence upon the institutions of the international S&T cooperation, rather they give indirect influence, through other related institutions, upon the institutions of the international S&T cooperation and make its gradual change or evolution. This is because the institutions of the international S&T cooperation have the "institutional layering".

• Management Science and Financial Engineering
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• v.19 no.1
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• pp.17-23
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• 2013

It has been studied that retailer's using a suboptimal (R, T) policy is often more desirable to make the best use of information flows than the locally optimal (s, S) policy in a two-stage serial supply chain. In this paper, by performing an extensive computational study, we tabulate the benefit of the retailer's using (R, T) policy instead of (s, S) policy in a supply chain with information sharing, and compare it to a maximum possible benefit that could be achieved in a centralized supply chain. We can understand the mechanisms of how the cost parameters and demand variance affect the benefit of the retailer's using (R, T) policy instead of (s, S) policy, by comparing decentralized and centralized systems.

• Journal of the Korean Mathematical Society
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• v.53 no.3
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• pp.709-723
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• 2016

Let C[0, t] denote a generalized Wiener space, the space of real-valued continuous functions on the interval [0, t] and define a random vector $Z_n:C[0,t]{\rightarrow}{\mathbb{R}}^n$ by $Zn(x)=(\int_{0}^{t_1}h(s)dx(s),{\cdots},\int_{0}^{t_n}h(s)dx(s))$, where 0 < $t_1$ < ${\cdots}$ < $t_n$ < t is a partition of [0, t] and $h{\in}L_2[0,t]$ with $h{\neq}0$ a.e. In this paper we will introduce a simple formula for a generalized conditional Wiener integral on C[0, t] with the conditioning function $Z_n$ and then evaluate the generalized analytic conditional Wiener and Feynman integrals of the cylinder function $F(x)=f(\int_{0}^{t}e(s)dx(s))$ for $x{\in}C[0,t]$, where $f{\in}L_p(\mathbb{R})(1{\leq}p{\leq}{\infty})$ and e is a unit element in $L_2[0,t]$. Finally we express the generalized analytic conditional Feynman integral of F as two kinds of limits of non-conditional generalized Wiener integrals of polygonal functions and of cylinder functions using a change of scale transformation for which a normal density is the kernel. The choice of a complete orthonormal subset of $L_2[0,t]$ used in the transformation is independent of e and the conditioning function $Z_n$ does not contain the present positions of the generalized Wiener paths.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.99-107
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• 2002

Impedance Spectroscopy (IS) has been used to study microstructure and hydration mechanism of cement pastes. In this work, the early hydration behaviour of portland cement paste with different blame values and contents of blast-furnace slag was investigated by IS. As slag was added to portland cement, the values of $R_{t(s+1)}$ (the solid-liquid phase resistance) and $R_{t(int)}$ were decreased in the early hydration period. It showed that hydration of cement paste containing slag was slower than it of the reference cement paste. As the content of slag was increased, the values of $R_{t(s+1)}$ was decreased. Furthermore, the diameter of semicircle, $R_{t(int)}$ observed at 72 hours was decreased with the increment of slag content. However, the values of $R_{t(s+1)}$ and $R_{t(int)}$ were increased with blame value of slag from the early hydration period.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.2
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• pp.119-123
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• 2010

We introduce and investigate the concepts of ($T_i,T_j$)-fuzzy $\beta$-(r, s)-open sets, ($T_i,T_j$)-fuzzy $\beta$-(r, s)-closed sets and fuzzy pairwise $\beta$-(r, s)-continuous mappings in smooth bitopological spaces.

• Journal of Aquaculture
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• v.11 no.2
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• pp.231-240
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• 1998

Tetraselmis is widely used as a live food because of its easy handling, high nutrient, large size and wide tolerant range of temperature and salinity. In order to find the optimum Tetraselmis species for mass culture in Korea, five species of this microalgae were examined on size, optimum culture condition ${\textperthousand}$s, $^{\circ}C.$) and nutrient composition. The results obtained were as follows: Among five species of Tetraselmis, T. sp.(Haeundae) was the largest(major axis $17.6{\pm}1.87^{\mu}$m, mean cell volume 727${\mu}$m), and T. sp. (China) the smallest (major axis $14.6{\pm}1.46^{\mu}$m, mean cell volume 625m). Tetraselmis was very eurythermal and euryhaline species. But optimum temperature and salinity for growth were 24~$30^{\circ}C.$ and 27~30${\textperthousand}$, respectively. Among five species of Tetraselmis, T. sp. (China) seemed to be the most tolerant of high temperature over $30^{\circ}C.$, and T. tetrathele of low temperature below $6^{\circ}C.$. In culture density, T. suecica showed the highest growth rate among the among the five species. The cell density of this microalgae attained to $141{\times}10^4$cells/ml at $24^{\circ}C.$ and 30${\textperthousand}$ within 7 days. In chemical composition, crude protein amount was the highest in T. suecica (44.50%), and crude lipid amount it T. sp. (Haeundae, 7.13%). Total essential amino acid amount was the highest in T. sp. (Haeundae, 50.4%) and total polyunsaturated amount in T. sp. (China, 11.7%) The results on growth and chemical composition of five species of Tetraselmis indicated that T. suecica seemed to be the most suitable species for mass culture in Korea.

• Journal of Life Science
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• v.12 no.5
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• pp.505-514
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• 2002

The aim of this study was to evaluate the anticonvulsant activity of four agents derived from tropinone (T-1: 2,4-dipyrrolylmethenylnortropinone, T-2: 2,4-diphenylmethenylnortropinone, T-3 : 2,4-difurfurylmethenylnortropinone, T-4 : 2,4-dimethoxyphenylmethenylnortropinone) in NIH Swiss mouse. Pentylenetetrazole (nZ) was injected via intraperi-toniurn in mouse and Maximal Electroshock (MES) stimulation was through both conjunctivas by electrodes. Tropinone derivatives were treated at 15 minutes before PTZ or MES procedure. PIZ of 25 mg/kg induced generalized seizure in mouse, effects of tropinone derivatives on PTZ-induced seizure were monitored. Compared with control group, T-4 decreased seizure grade most effectively. Also T-4 increased onset time of PTZ-induced seizure. This result showed that T-4 is most effective on PTZ-induced seizure. In MES-induced seizure, T-1 decreased seizure grade and recovery time. nNOS expression in hippocampus and cortex were increased in nZ- and MES-induced seizure animals compared with control. Pretreatment of tropinone derivatives in PTZ-induced seizure did not affected nNOS expression in brain tissues, but T-1 and T-4 decreased nNOS expression in cortex of MES-induced seizure animals. These findings suggest that tropinone derivatives have specific anticonvulsant activities according to PTZ- and MES-induced seizure. 2,4- dimethoxyphenylmethenylnoroopinone is most effective in PTZ-induced seizure and 2,4-di methoxyphenylmethenylnortropinone is most effective in MES-induced seizure.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1505-1508
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• 1994

Lately in KEPCO, the power plant capacity has increasingly become larger than before and it has become difficult to get R.O.W for T/L. Therefore KEPCO decided to increase its system voltage level from 345kV to 765kV. By doing this, KEPCO would like to expand its transmission capability by less T/L route. In 765kV system, we should consider various kinds of environmental impacts that can be neglected in lower voltage level. These environmental impacts are very important factor in T/L design. That can be changed greatly according to the selected conductor. And also conductor selection has relation with the economy of T/L construction directly. This paper deals with some general factors to be considered and basic principles about the conductor and ground wire selection for 765KV T/L with referring to the experiences of foreign utilities.

• Journal of information and communication convergence engineering
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• v.16 no.2
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• pp.93-98
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• 2018

The Internet of Things (IoT) is a form of the emerging 4th industry in the 5G era. IoT is expected to develop naturally in our daily life in the 5G era in which high-speed communication will be completed. Along with the rise of IoT, concerns about security and malicious attacks are also increasing. This paper examines DoS attacks, which are one of the representative security threats of IoT and proposes a local detection and blocking system that are suitable for response to such attacks. First, systems of the LoRaWAN type, which are most actively researched in the IoT system field and DoS attacks that can occur in such systems were examined. Then, the inverse order tree algorithm using regional characteristics was designed as a cluster analysis form. Finally, a system capable of defending denial-of-service attacks in the 5G IoT system using local detection and blocking with the Euclidean distance was designed.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.697-703
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• 2007

In this paper, we focuses on the development of Takagi-Sugeno (T-S) fuzzy modeling in a nonlinear container crane system. A T-S fuzzy model is characterized by fuzzy "if-then" rules which represent the locally input-output relationship whose consequence part is described by a state space equation as subsystem. The T-S fuzzy model in container cranes first obtains a few number of linear models according to operation conditions and blends these conditions using fuzzy membership functions. Parameters of the membership functions are adjusted by a RCGA to have same dynamic characteristics with nonlinear system of a container crane. Simulations are given to illustrate the performance of T-S fuzzy model.