• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.11a
• /
• pp.26-26
• /
• 2003

Lithium storage electrodes for rechargeable batteries require mixed electronic-ionic conduction at the particle scale in order to deliver desired energy density and power density characteristics at the device level. Recently, lithium transition metal phosphates of olivine and Nasicon structure type have become of great interest as storage cathodes for rechargeable lithium batteries due to their high energy density, low raw materials cost, environmental friendliness, and safety. However, the transport properties of this family of compounds, and especially the electronic conductivity, have not generally been adequate for practical applications. Recent work in the model olivine LiFePO$_4$, showed that control of cation stoichiometry and aliovalent doping results in electronic conductivity exceeding 10$^{-2}$ S/cm, in contrast to ~10$^{-9}$ S/cm for high purity undoped LiFePO$_4$. The increase in conductivity combined with particle size refinement upon doping allows current rates of >6 A/g to be utilized while retaining a majority of the ion storage capacity. These properties are of much practical interest for high power applications such as hybrid electric vehicles. The defect mechanism controlling electronic conductivity, and understanding of the microscopic mechanism of lithiation and delithiation obtained from combined electrochemical and microanalytical techniques, will be discussed

• Journal of the Korean Operations Research and Management Science Society
• /
• v.28 no.3
• /
• pp.135-148
• /
• 2003

In this paper we introduce the Internet-based purchase support systems using data mining and case-based reasoning (CBR). Internet Business activity that involves the end user is undergoing a significant revolution. The ability to track users browsing behavior has brought the vendor and end customer's closer than ever before. It is now possible for a vendor to personalize his product message for individual customers at massive scale. Most of former researchers, in this research arena, used data mining techniques to pursue the customer's future behavior and to improve the frequency of repurchase. The area of data mining can be defined as efficiently discovering association rules from large collections of data. However, the basic association rule-based data mining technique was not flexible. If there were no inference rules to track the customer's future behavior, association rule-based data mining systems may not present more information. To resolve this problem, we combined association rule-based data mining with CBR mechanism. CBR is used in reasoning for customer's preference searching and training through the cases. Data mining and CBR-based hybrid purchase support mechanism can reflect both association rule-based logical inference and case-based information reuse. A Web-log data gathered in the real-world Internet shopping mall is given to illustrate the quality of the proposed systems.

• Journal of Korea Multimedia Society
• /
• v.3 no.3
• /
• pp.209-223
• /
• 2000

As the importance and utilization of multimedia data increases, it becomes necessary to represent and manage multimedia data within database systems. In this paper, we designed and implemented an image retrieval system which support efficient management and intelligent retrieval of image data using concept hierarchy and data mining techniques. We stored the image information intelligently in databases using concept hierarchy. To support intelligent retrievals and efficient web services, our system automatically extracts and stores the user information, the user's query information, and the feature data of images. The proposed system integrates user metadata and image metadata to support various retrieval methods on image data.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.2
• /
• pp.276-283
• /
• 2003

In this paper, a 2-stage power amplifier(PA) for IMT-2000 handset has been designed and fabricated using SiGe HBT, which has excellent frequency characteristics and linearity, to reduce size and weight instead of existing linearization techniques. DC I-V characteristics and S-parameter of SiGe HBT were simulated by Agilent circuit simulator(ADS), with large signal Gummel-Poon nonlinear circuit model. Then the output and interstage matching circuits were designed to satisfy the high power condition and the high gain condition, respectively. The experimental results showed output power of 27.1dBm and ACLR of 20dB, PAE of 34%, and linear power gain of 18.9dB over frequency ranges from 1920MHz to 1980MHz.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.627-627
• /
• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• Journal of Korean Institute of Industrial Engineers
• /
• v.39 no.5
• /
• pp.361-366
• /
• 2013

Prediction of process parameters is very important in parameter design. If predictions are fairly accurate, the quality improvement process will be useful to save time and reduce cost. The concept of dual response approach based on response surface methodology has widely been investigated. Dual response approach may take advantages of optimization modeling for finding optimum setting of input factor by separately modeling mean and variance responses. This study proposes an alternative dual response approach based on machine learning techniques instead of statistical analysis tools. A hybrid neural network-genetic algorithm has been proposed for the purpose of parameter design. A neural network is first constructed to model the relationship between responses and input factors. Mean and variance responses correspond to output nodes while input factors are used for input nodes. Using empirical process data, process parameters can be predicted without performing real experimentations. A genetic algorithm is then applied to find the optimum settings of input factors, where the neural network is used to evaluate the mean and variance response. A drug formulation example from pharmaceutical industry has been studied to demonstrate the procedures and applicability of the proposed approach.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.6
• /
• pp.1519-1530
• /
• 1997

Object-oriented software, reusability enables to specialize the software techniques by leading the user friendly thought and meets the user's need only concentrating on convenience of development environment. Reuse effect can be maximized through retrieval system. In this paper, we development the MT-Views(Multiple-Template Views) to realize the reuse effect as integrated reuse system including retrieval, understanding and rebuilding tools based on class library. We used the hybrid retrieval model for easy and efficient retrieval of similar software components. With using these tools, users can retrieve the reusable components and reuse the components for constructing therir own applications. Also, we can acquire many informations about retrieved components, so can rebuild components conforming our original intend.

• Korean Journal of Microbiology
• /
• v.23 no.1
• /
• pp.64-68
• /
• 1985

In this study, hybridoma techniques were applied to produce monoclonal antobodies to Paragonimus westermani, commonly known as lung distoma. Balb/c mice were immunized intraperitoneally every week with increasing doses of purfied protein of Paragonimus westermani adult worms begining with 0.3/mg/mouse/7 days and ending with 0.5mg at 28th day. Spleen cells from these immunized mice were hybridized with myeloma cells (NS-1) and the hybridized cells were selected in HAT media. The antibody secreting cells among the hybrid cells were initially selected by ELISA. Those initially selected cells were further screened by the criteria of antibody producing activity, and seneral cell lines among them were further tested with immunodiffusion method. One hybridoma clone produced IgM and another clone produced IgG1. The supernatant of the hybridoma clone producing IgM had titer 1:64 and the hybridoma clone producing IgG1 had titer 1:256 measured by immunofluorescence technique.

• The Journal of Information Systems
• /
• v.26 no.2
• /
• pp.105-121
• /
• 2017

Purpose It is a major goal to improve the product yields during production operations in the manufacturing industry. Therefore, factory is trying to keep the good quality materials and proper production resources, also find the proper condition of facilities and manufacturing environment for yields improvement. Design/methodology/approach We propose the hybrid framework to analyze to dataset extracted from MES. Those data is about the alarm information generated from equipment, both measurement and equipment process value from production and cycle/pitch time measured from production data these covered products during production. We adapt a data warehousing techniques for organizing dataset, a logistic regression for finding out the significant factors, and a association analysis for drawing the rules which affect the product yields. And then we validate the framework by applying the real data generated from the discrete process in secondary cell battery manufacturing. Findings This paper deals with challenges to apply the full potential of modeling and simulation within CPPS(Cyber-Physical Production System) and Smart Factory implementation. The framework is being applied in one of the most advanced and complex industrial sectors like semiconductor, display, and automotive industry.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.8
• /
• pp.2584-2592
• /
• 2011

Nickel nanoparticle-poly(N-vinyl-2-pyrrolidone)/$TiO_2-ZrO_2$ composite (Ni-PVP/$TiO_2-ZrO_2$) was prepared by in situ polymerization method. The physical and chemical properties of Ni-PVP/$TiO_2-ZrO_2$ were investigated by XRD, FT-IR, BET, TGA, SEM and TEM techniques. The catalytic performance of this novel heterogeneous catalyst was determined for the Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid in the presence of methanol-water mixture as solvent. The effects of reaction temperature, the amount of catalyst, amount of support, solvent, and amount of metal for the synthesis of Ni-PVP/$TiO_2-ZrO_2$, were investigated as well as recyclability of the heterogeneous composite. The catalyst used for this synthetically useful transformation showed considerable level of reusability besides very good activity.