• Clean Technology
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• v.11 no.4
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• pp.189-194
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• 2005

Carboxymethylcellulose(CMC) which is water-soluble fiber was manufactured by mercerization and etherification in the earlier study. Experimental parameters were conversion time for each step, concentration of reagent and temperature. To know the presence of functional group, CMC was analyzed by FT-IR(Fourier Transform Infrared) spectroscopy. Ethanol was recovered using evaporator and purity of ethanol analyzed by GC-MASS was 97% and 83% after mercerization and etherification respectively. For the pilot plant, if CMC is folded by 40 times it showed maximum efficiency. Maximum solubility was obtained when the ratio of NaOH and MCA is 3 : 4.5.

• Journal of Digital Contents Society
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• v.18 no.4
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• pp.769-775
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• 2017

The International Maritime Organization's e-Navigation strategy is to introduce new technologies to ships to support easier and safer navigation. With the e-Navigation strategy, various equipment will be installed in vessels and the system structure will be linked to onshore systems. For this reason, a common data structure between systems became necessary, and finally the S-100 standard developed by the International Hydrographic Organization was selected. This paper describes a design of marine casualty data model based on the S-100 standard. The data model of the S-100 standard is designed in the form of a UML class diagram, and the final encoding follows the GML / XML format. We will look at the S-100 standard and product specifications under development, and describe the S-100 standards-based data design and portrayal definition of marine accident data.

• Journal of Korean Elementary Science Education
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• v.19 no.2
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• pp.29-41
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• 2000

The purpose of this study is to examine the effects of the Portfolio applied science instruction on the students' scientific affective domain and perceptions of portfolio in elementary schools. Portfolio applied science instruction of the 6th grade science unit 'Environment pollution and Nature protection' was developed for this study. Traditional instruction was implemented to the control group and portfolio applied science instruction was implemented to the experimental group. Pretests of the scientific affective domain were administered to both groups. The treatment was given for about seven weeks for both groups. Instruments about scientific affective domain were administered to both groups. A questionnaire on perception of portfolio applied science instruction was given to the experimental group after the treatment. The results were analyzed using t-test on the students' scientific affective domain. The results of this study are as follows: 1. Portfolio applied science instruction program for elementary schools was developed. Students themselves determine the portfolio learning goal in a portfolio applied science instruction. Students construct the portfolio and they evaluate themselves and other colleagues. Also teachers go on portfolio applied science instruction considering portfolio purpose, concepts, evaluation. 2. There was not a statistically meaningful difference between an experimental group and a control group o]1 the students' scientific affective domain. In three sub categories of a scientific affective domain, the science perception, the interest on science and scientific attitude, there were not statistically meaningful difference among them. 3. As the results of the questionnaire on perceptions of portfolio, they didn't understand it very well but after learning portfolio, they showed positive attitude to perceptions of portfolio. Students in portfolio applied science instruction like more the portfolio applied science instruction than general instruction. 4. Portfolio applied science instruction has an useful value as a method of teaching and evaluation. Students and teachers can produce various portfolios products in portfolio applied science instruction. As a conclusion, portfolio applied science instruction was not statistically meaningful on the students' scientific affective domain, but it gives positive effects on perceptions of portfolio in elementary schools. Therefore, portfolio has an educational value as a method of teaching and evaluation for students' growth. In the future, teachers and students must have interaction and feedback in portfolio applied science instruction.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1243-1256
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• 1997

Object modeling has been cinsidered as an efficient technique for eleciting user requirements and communicat-ing between developers and customers. But model itself is not easy to understand what recult will be after coding and whether it will be meet with the requirements of customers. In this paper, we developed the envuroment for visualization of object model for validating with rewuirnent at the early stage. Therefore, we defined correct and complete rules which can transform the object model.the delierables of Shler/Mellor's method, into a for-mal specification language of VDM(Vienna Development Methods) with a mathematical basis. This basis provides the means of proving that a specification is realizable and proving properties of a system.Therefore.the completeness, preciceness of object model can be verified by proving the transformed VDM specification and prototyping by constructing a visualization supporting enviroment.

• Journal of Digital Convergence
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• v.18 no.3
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• pp.111-121
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• 2020

The purpose of this study is to examine the satisfaction of consumers using the mobile navigation service which is continuously growing. This study examined variables that affect the service use behaviors and satisfaction of 1200 consumers using service. According to the results of the study, consumers used the service 1-2 or 3-4 times per week, more frequently used in the lunch time(weekends) and in the morning(weekdays). The core functional dimension was shown to have the largest effect on satisfaction with the service. Among consumption emotions, positive emotions had effects in the positive direction while negative emotions had effects in the negative direction, and the effect of innovativeness was not significant. Through the foregoing, the use behavior and the formation of satisfaction could be analyzed and the results of this study can be used in establishing service strategies later and can be also used as basic data of the navigation industry.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.3
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• pp.183-190
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• 2002

This paper describes the synthesis of robust and non-fragile H$\infty$ state feedback controllers for linear varying systems with affine parameter uncertainties, and static state feedback controller with structured uncertainty. The sufficient condition of controller existence, the design method of robust and non-fragile H$\infty$ static state feedback controller, and the set of controllers which satisfies non-fragility are presented. The obtained condition can be rewritten as parameterized Linear Matrix Inequalities(PLMls), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. However, in contrast to LMIs, PLMIs feasibility problems involve infinitely many LMIs hence are inherently difficult to solve numerically. Therefore PLMls are transformed into standard LMI problems using relaxation techniques relying on separated convexity concepts. We show that the resulting controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a degree.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.38-45
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• 2009

In this paper, we propose an efficient cooperative diversity technique, which partition the codewords of each mobile and transmit portions of each codeword through independent fading channels using duo-binary turbo codes. A coded diversity technique can achieve high cooperative diversity gain by decoding and transmitting of the re-encoded signal, while this can also cause high performance degradation due to failure of the decoding. In this paper, we introduce various coded diversity technique using duo-binary turbo codes which are defined as channel coding schemes in the IEEE WiMax specification, and also demonstrate performance simulation results with the analysis. We also propose a cooperative diversity technique using rate-compatible duo-binary turbo codes, where user terminals with different parity symbols cooperate each other. Simulation results investigated in this paper reveal that the proposed scheme show high diversity gain at a reasonal SNR range.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.35-42
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• 2008

In this paper, we propose a fast coeff_token decoding method based on the re-constructed VLCT. Since the conventional decoding method is still based on large memory accesses, it is not suitable for the multimedia services such as PMP, PMB, DVH-H where fast decoding and low power consumption are required. Based on the analysis for the codeword structure, new structure of the codeword and the corresponding memory architecture are developed in this paper. The simulation results show that the proposed algorithm achieves memory access saving from 10% to 57%, compared to the conventional decoding method. This meant that the issues of tow power consumption and high speed decoding can be resolved without video-quality and coding efficiency degradation.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.711-720
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• 1995

This paper describes in object-oriented retrieval framework that is generally designed to store and retrieve the reusable components from the library regardless of the underlying representation of the library. We propose a retrieval framework on visual space so that reuser can identify their location at the library without any previous information of library structure. They can decide the directions of retrieval with the results displayed on the visual space and interact with the library using the defined simple retrieval operation that can assess the library information object. For doing this, 4I model was proposed. Librarian as well as reuser can easily construct the new library on the visual environment. It is the process to give the semantic of the information object. This paper discusses the basic concepts of our 4I model and explains each constituent of our model and shows a simple example of the system.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.645-654
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• 1995

A distributed DBMS integrates local schemas that are independently designed, maintained, and managed by different users at each site providing a global virtual schema. This global schema supports users at a specific site to transparently utilize local database at different sites. The security features of the local schema should also not be changed in the global schema integrating security features of each local schema. Researches on the integration of security features into local schema in distributed DBMS environment, however, are very rate. This pater using the multilevel secure object-oriented database model(as the model for the definition of a local schema in distributed environment) which is an extension of the object-oriented models. It also suggests eight integration methods that can maintain the security features of local schemas. The eight methods are classified by the object classes and by relationships among them.