• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.257-264
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• 2003

This study has investigated the temperature-sensitive liposomes, which release anticancer drug(doxorubicin) at the hyperthermia temperature$(~40^{\circ}C)$. The temperature-sensitive liposomes were modified with a copolymers of N-isopropylacrylamide(NIPAAm) and acrylamide(AAm), which exhibit a lower critical solution temperature (LCST) at the hyperthermia temperature. The release of doxorubicin from the modified liposomes was determined by measuring the fluorescence intensity with changing temperature and time. The release of doxorubicin from liposomes modified with poly(NIPAAm-co-AAm) copolymer was increased significantly, because poly(NIPAAm-co-AAm) could undergo the conformational transition in the narrow hyperthermia temperature region$(~40{\pm}2^{\circ}C)$. Moreover, we observed that doxorubicin released from liposomes within 5 minutes, and the size of modified liposomes was 120~170 nm. In this study, we have prepared temperature-sensitive liposomes which could be controlled by temperature. They can be applied in the field of a drug delivery system for tumor targeting by temperature control.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.177-185
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• 2017

In the present work, the interaction of fatty acid with vesicle membrane of phospholipids was investigated using 3 different kinds of fatty acids such as stearic acid (SA), oleic acid (OA) and linoleic acid (LA). Basically, the same trend has been found in 3 fatty acid systems. The addition of fatty acid produced a close packing of liposome due to the penetration of fatty acid molecules into liposome vesicles, which resulted in a decrease in size and an increase in zeta potential of liposome. However, excessive addition of fatty acid produced a transition from liposomes to aggregates of lipid particles having polymorphic structure. The membrane fluidity, characterized by measuring membrane deformability and fluorescence anisotropy ratio of liposomes, was in good agreement with measurement results of transmission electron microscopy (TEM) and particle size. The minimum size and closest packing of liposome with SA, OA and LA were found when the molar ratios of fatty acid to lecithin were 0.70, 0.50, and 0.25 respectively.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.632-638
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• 2006

There are numerous approaches available to cleanup a contaminated surface and subsurface ground currently in use, however, these methods all classify the decontamination after the contamination has penetrated into the soil masses and is costly. Unlike these approaches, in this study, utilization of soil's self-decontamination ability by rearranging and preplanning of the topographical features and surface and subsurface drainage systems for the potential contamination sites before or during contamination process has been considered as an another cleanup method. Step by step explanations on why and how to develop the self-decontamination procedure is proposed in detail. Two examples are presented including contaminated saltwater intrusion along a coastal region and control or prevention of radioactive toxic radon gas ($^{222}Rn$) in residential areas. The effectiveness of the proposed systems to these two examples using the soil's self-decontamination ability is well illustrated.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.14-23
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• 1994

In this paper, speech units appropriate for recognition of Korean language have been studied. For better speech recognition, co-articulatory effects within an utterance should be considered in the selection of a recognition unit. One way to model such effects is to use larger units of speech. It has been found that diphone is a good recognition unit because it can model transitional legions explicitly. When diphone is used, stationary phoneme models may be inserted between diphones. Computer simulation for isolated word recognition was done with 7 word database spoken by seven male speakers. Best performance was obtained when transition regions between phonemes were modeled by two-state HMM's and stationary phoneme regions by one-state HMM's excluding /b/, /d/, and /g/. By merging rarely occurring diphone units, the recognition rate was increased from $93.98\%$ to $96.29\%$. In addition, a local interpolation technique was used to smooth a poorly-modeled HMM with a well-trained HMM. With this technique we could get the recognition rate of $97.22\%$ after merging some diphone units.

• Polymer(Korea)
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• v.24 no.6
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• pp.837-844
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• 2000

The cure behavior of commercial epoxy molding compounds (EMC) commonly used for IC package was studied at constant cure temperatures as well as at constant heating rates using differential scanning calorimetry (DSC), rheometer, and dielectric analyzer (DEA). The cure kinetics were obtained using autocatalytic reaction model according to the Ryan Dutta method after assuming m+n equal to 2. The prediction of reaction rates by the model equation corresponded well to experimental data at all temperatures except for 10$0^{\circ}C$. The phase transitions such as gelation and vitrification occurred during network formation. At each isothermal cure temperature, $T_{g}$ was measured in accordance with cure time, and the vitrification point was attained when $T_{g}$ was equal to $T_{cure}$. The temperature dependence of gel points and vitrification points showed good agreement with Arrhenius relation. DEA using parallel plate electrode was effective for the monitoring of EMC cure. we knew that if the resin systems are materials of comparable quality, $_{gel}$$T_{g}$ is constant regardless of accelerator concentration in TTT (Time-Temperature-Transformation) diagram.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.4
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• pp.211-216
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• 2017

This paper proposes image processing techniques that improve usability and performance in a diagnostic system of the contrast-enhanced ultrasonography. For a methodology for visualizing diagnostic parameter data in an ultrasonic medical image, an expression of transition time data with successive pixel values and a method of generating a lesion diagnostic parameter image with four categorized values are presented. We also introduce a MRF-based image enhancement technique to eliminate noises from generated parametric images. Such parametric image generation technique can overcome the difficulty of discriminating dynamic change in patterns in the ultrasonography. The technique clarifies the contour of the region in the original image and facilitates visual determination of the characteristics of the lesion through four colors. With regard to this MRF-based image enhancement, we define the energy function of consecutive pixel values and develop a technique to optimize it, and the usability of the proposed theory is examined through experiments with medical images.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.239-245
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• 2020

Recently, BIM (Building Information Modeling) are widely being utilized in Construction industry. However, most structures that have been constructed in the past do not have BIM. For structures without BIM, the use of SfM (Structure from Motion) techniques in the 2D image obtained from the camera allows the generation of 3D model point cloud data and BIM to be established. However, since these generated point cloud data do not contain semantic information, it is necessary to manually classify what elements of the structure. Therefore, in this study, deep learning was applied to automate the process of classifying structural components. In the establishment of deep learning network, Inception-ResNet-v2 of CNN (Convolutional Neural Network) structure was used, and the components of bridge structure were learned through transfer learning. As a result of classifying components using the data collected to verify the developed system, the components of the bridge were classified with an accuracy of 96.13 %.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1043-1051
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• 2008

In polyolefin processes melt index (MI) is the most important controlled variable indicating product quality. Because of the difficulty in the on-line measurement of MI, a lot of MI estimation and correlation methods have been proposed. In this work a new dynamic MI estimation scheme is developed based on system identification techniques. The empirical MI estimation equation proposed in the present study is derived from the $1^{st}$-order dynamic models. Effectiveness of the present estimation scheme was illustrated by numerical simulations based on plant operation data including grade change operations in high density polyethylene (HDPE) processes. From the comparisons with other estimation methods it was found that the proposed estimation scheme showed better performance in MI predictions. Using the model predictive control method based on the present dynamic MI estimation model, MI values are estimated and compared with those of MI setpoints. From the numerical simulation of the proposed control system, it was found that significant reduction of transition time and the amount of off-spec during grade changes were achieved.

• Journal of Korea Port Economic Association
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• v.27 no.3
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• pp.161-177
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• 2011

Nowadays, a capital flow and intimacy of financial system among countries have been increasing in global financial environment. So it is easily possible that the risk of some countries which are in financial crisis infects other countries in the world. A recent global financial crisis reminds countries in East Asia of advancing the financial cooperation as well as financial integration. Countries in East Asia agreed with the Chiang Mai Initiative to prevent a recurrence of financial crisis in East Asia. A bilateral swap arrangement of the CMI has several purposes in order to offer foreign currency liquidity against economic crisis, remove the opportunity cost of foreign exchange reserve, push ahead the financial integration, increase the export-import logistics and so on. This paper analyzes the effect of financial cooperation in East Asia on the export-import logistics with random effect estimation and fixed effect estimation. As a result, each of country in East Asia is able to increase almost 10.3% of the export-import logistics on average.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.575-577
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• 2013

The research was aimed at the hotel industry's employees in order to test the efficiency of e-Learning, which is emerging as the alternative training system to the conventional one. The independent variables are the quality of e-Learning, including the qualities of the system, contents, and service of e-Learning, and the learning characteristic factor, including the quality factor of e-Learning, the self-efficacy of the user, learning motivation, and the flow of learning. Furthermore, the intervening variables are its perceived usefulness and the satisfaction factor of the user known as the so-called utility of e-Learning, continuous intention to use in terms of efficaciousness, and the spread of education and training. The dependent variable is customer orientation, known as the ultimate efficaciousness of corporate e-Learning.