• The KIPS Transactions:PartC
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• v.12C no.7 s.103
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• pp.1057-1066
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• 2005

WebDAV(Web-based Distributed Authoring and Versioning), a protocol which supports web-based distributed authoring and versioning, provides a standard infrastructure for asynchronous collaboration on various contents through the Internet. A WebDAV property management is a function to set and manage the main information of the resources as properties, and a user property, one kind of the WebDAV properties, has the ability to be freely defined by users. This free definition of user property makes it very useful to develop web-based applications like a collaboration system based on WebDAV However, with an existing WebDAV property management scheme, there is a limit to develop various applications. This paper describes a DavUP(WebDAV User property design Protocol) protocol which extended the original WebDAV and its uti-lization which efficiently supports management of WebDAV user properties. DavUP needs the definition of the collection structure and type definition properties for an application. To do this, we added a new header md appropriated WebDAV method functions to the WebDAV protocol. To show the usefulness of DavUP protocols, we extended our DAVinci WebDAV server to support DavUP Protocols and experimentally implemented a general Open Workspace, which provides effective functions to share and exchange open data among general users, on the DAVinci.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.418-418
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• 2008

The electrochemical etching of silicon in HF-based solutions is known to form various types of porous structures. Porous structures are generally classified into three categories according to pore sizes: micropore (below 2 nm in size), mesopore (2 ~ 50 nm), and macropore (above 50 nm). Recently, the formation of macropores has attracted increasing interest because of their promising characteristics for an wide scope of applications such as microelectromechanical systems (MEMS), chemical sensors, biotechnology, photonic crystals, and photovoltaic application. One of the promising applications of macropores is in the field of MEMS. Anisotropic etching is essential step for fabrication of MEMS. Conventional wet etching has advantages such as low processing cost and high throughput, but it is unsuitable to fabricate high-aspect-ratio structures with vertical sidewalls due to its inherent etching characteristics along certain crystal orientations. Reactive ion dry etching is another technique of anisotropic etching. This has excellent ability to fabricate high-aspect-ratio structures with vertical sidewalls and high accuracy. However, its high processing cost is one of the bottlenecks for widely successful commercialization of MEMS. In contrast, by using electrochemical etching method together with pre-patterning by lithographic step, regular macropore arrays with very high-aspect-ratio up to 250 can be obtained. The formed macropores have very smooth surface and side, unlike deep reactive ion etching where surfaces are damaged and wavy. Especially, to make vertical microwire or nanowire arrays (aspect ratio = over 1:100) on silicon wafer with top-down photolithography, it is very difficult to fabricate them with conventional dry etching. The electrochemical etching is the most proper candidate to do it. The pillar structures are demonstrated for n-type silicon and the formation mechanism is well explained, while such a experimental results are few for p-type silicon. In this report, In order to understand the roles played by the kinds of etching solution and mask patterns in the formation of microwire arrays, we have undertaken a systematic study of the solvent effects in mixtures of HF, dimethyl sulfoxide (DMSO), iso-propanol, and mixtures of HF with water on the structure formation on monocrystalline p-type silicon with a resistivity with 10 ~ 20 $\Omega{\cdot}cm$. The different morphological results are presented according to mask patterns and etching solutions.

• Journal of the Korea Concrete Institute
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• v.19 no.3
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• pp.377-383
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• 2007

In recent years the field application of high performance concrete has been increased to improve the quality and reliability of concrete structures. The mix design of the high performance concrete includes the 2 set-off mixture theory of mortar and coarse aggregate and that of paste and aggregate. The 2 set-off mixture theory of mortar and coarse aggregate has a problem of having to determine its value through repeated experiments in applying the rheological characteristics of mortar. The 2 set-off mixture theory of paste and aggregate has never been applied to high performance concrete since it doesn't take into account the relationship between optimum fine aggregate ratio and unit volume of powder nor does it consider the critical aggregate volume ratio. As the mixture theory of these high performance concretes, unlike that of general concrete, focuses on flowability and charge-ability, it does not consider intensity features in mix design also, the unit quantity of the materials used is determined by trial and error method in the same way as general concrete. This study is designed to reduce the frequency of trial and error by accurately calculating the optimum fine aggregate ratio, which makes it possible to minimize the aperture of aggregate in use by introducing the maximum density theory to the mix design of high performance concrete. Also, it is intended to propose a simple and reasonable mix design for high performance concrete meeting the requirements for both intensity and flowability. The mix design proposed in this study may reduce trial and error and conveniently produce high performance concrete which has self-chargeability by using more than the minimum unit volume of powder and optimum fine aggregate with minimum porosity.

• Journal of Korean Elementary Science Education
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• v.27 no.4
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• pp.385-398
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• 2008

The purpose of this study is to understand the effect of The Model of Phases of the Moon on conception changes for preservice teachers. The researcher interviewed two preservice teachers under the agreement with them on their participation in the research just before he performed a class using The New Model of Phases of the Moon. The post-interview with the same content as the pre-interview was preformed one month later. The main content of the interview is as follows; 'Explain the shape of the Moon by drawing it.', 'Explain the relative different position among the Sun, Earth, and Moon depending on phases of the Moon by drawing them.', 'What do you think of the cause of phases of the Moon?', 'Draw a picture to explain why we always see only one side of the moon.' The results of the research are as follows. First, the class with New Model of Phases of the Moon was able to perceive the relationship of Sun, Earth, and Moon in three-dimensions rather than in two-dimensions and it helped to change their misconception that the Moon's shadow causes the Moon's shape. Secondly, the class with New Model of Phases of the Moon helped preservice teachers understand better the different positional relationships among the Sun, Earth, and Moon depending on the Moon shapes. Third, the class adopting the New Model of Phases of the Moon help preservice teachers form scientific conceptions on the causes of phase change of the Moon. Fourth, the class with the New Model of Phases of the Moon is not appropriate for explaining the reason why only one face of the Moon is seen. Based upon the results above, the researcher realized the limitation of this model and suggested that this model would help learners understand phase change of the Moon and increase space perception ability.

• Journal of The Korean Association For Science Education
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• v.34 no.8
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• pp.795-806
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• 2014

The purpose of this study is to develop an intervention program for improvement of elementary science-poor students' Basic Science Process Skill (BSPS) and to validate the intervention program's effectiveness using eye-tracker. The participants of this study were 35 elementary science-poor students. This study's method was the analysis of real-time eye movements during basic science process skill problem solving. SMI's 120 Hz iView XTM RED was used to collect EMD (eye movement data). Experiment 3.4 and BeGaze 3.4 programs were used to design experiment and to analyze EMD. The results of this study are as follows. First, we developed an intervention program including BSPS instructional strategy, behavior of teachers & student according instructional strategy stage, teachinglearning plan and learning note. Second, science poor students' BSPS ability has improved statistically significantly through the application of intervention program and BSPS problem-solving time decreased statistically significantly. Third, AFT (average fixation time) of BSPS Question and keyword area decreased statistically significantly. Fourth, APD (average pupil diameter) of BSPS problem-solving process expanded statistically significantly. Fifth, AST (average saccade time) of BSPS problem-solving process increased statistically significantly. Sixth, AFET (average fixation entry time) of BSPS problem-clue area was accelerated statistically significantly, AFT of BSPS problem-clue area reduced statistically significantly.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.3
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• pp.194-201
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• 2014

This paper is able to be solved by improving degradation in multi-path environment by adjust beam pattern angle through modifying pulse phase of each antennas by using TRM (Transmitter Receiver Module). Beam Scanning Array Antenna, which is transmitter/receiver that improves degradation in multi-path environment without any signal distortion, is designed and manufactured. Beam Scanning Array Antenna should be able to send/receive signal at the antenna's longitudinal part without distortion and should not influences other systems. Also, it should include target detecting ability by beam steering.Dispersion characteristic of Beam Scanning Antenna, which is designed, is analysed by using fidelity, and steering and radar resolution performance is verified by using $1cm{\times}1cm$ sized target. To manufacture Beam Scanning Array Antenna, control board and GUI, which is able to control Vivaldi Antenna for IR-UWB, Tri-Band Wilkinson power divider, and TRM (Transmitter Receiver Module), is designed. Throughout this research, developed Beam Scanning UWB Array Antenna system is adoptable for radar application field. and time domain analysis techniques by using network analyser made the antenna characteristics analysis for setting up antenna more accurate. In addition, it makes beam width checking without difficulties.

• Journal of Life Science
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• v.28 no.1
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• pp.68-77
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• 2018

The purpose of this study was to isolate the probiotic lactic acid bacteria, and verify the possibility of the final selection strain as probiotic material. For screening of biogenic amines non-producing microorganisms, 42 lactic acid bacteria were isolated from various berries, extract and vinegar grown in Sunchang. Isolates were investigated for various physiological activities such as extracellular enzyme, antimicrobial and antioxidant activities, and 5 isolates were firstly screened. SBB07 was finally selected by analyzing the biogenic amine, and named Lactobacillus brevis SBB07 by 16S rRNA sequencing analysis. Next, SBB07 was assayed for their survival ability when exposed to acidic and bile conditions as well as heat and antibiotic resistance. As a result, SBB07 showed more than 86% and 54% higher survival rate in acidic condition at pH 2.0 and bile resistance with 0.5% oxgall. In addition, SBB07 showed a survival rate of more than 113% in $60^{\circ}C$, and also confirmed that it has resistant to various antibiotics. As a result of confirming the possibility of prebiotics, SBB07 showed the best utilization of GOS as a prebiotic substrate, and utilization of FOS and inulin were also high. These results suggest that SBB07 have good potential for application as probiotic lactic acid bacteria.

• Molecules and Cells
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• v.40 no.6
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• pp.386-392
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• 2017

Periodontal ligament stem cells (PDLSCs) are multipotent stem cells derived from periodontium and have mesenchymal stem cell (MSC)-like characteristics. Recently, the perivascular region was recognized as the developmental origin of MSCs, which suggests the in vivo angiogenic potential of PDLSCs. In this study, we investigated whether PDLSCs could be a potential source of perivascular cells, which could contribute to in vivo angiogenesis. PDLSCs exhibited typical MSC-like characteristics such as the expression pattern of surface markers (CD29, CD44, CD73, and CD105) and differentiation potentials (osteogenic and adipogenic differentiation). Moreover, PDLSCs expressed perivascular cell markers such as NG2, ${\alpha}-smooth$ muscle actin, platelet-derived growth factor receptor ${\beta}$, and CD146. We conducted an in vivo Matrigel plug assay to confirm the in vivo angiogenic potential of PDLSCs. We could not observe significant vessel-like structures with PDLSCs alone or human umbilical vein endothelial cells (HUVECs) alone at day 7 after injection. However, when PDLSCs and HUVECs were co-injected, there were vessel-like structures containing red blood cells in the lumens, which suggested that anastomosis occurred between newly formed vessels and host circulatory system. To block the $SDF-1{\alpha}$ and CXCR4 axis between PDLSCs and HUVECs, AMD3100, a CXCR4 antagonist, was added into the Matrigel plug. After day 3 and day 7 after injection, there were no significant vessel-like structures. In conclusion, we demonstrated the perivascular characteristics of PDLSCs and their contribution to in vivo angiogenesis, which might imply potential application of PDLSCs into the neovascularization of tissue engineering and vascular diseases.

• Journal of Information Technology Application
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• v.3 no.2
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• pp.103-132
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• 2001

The internet-based business is considered as a new strategic alternative for small-medium size companies. However, very little research about them has been reported. The objectives of this study are to analyze factors influencing the operation for the sites(we call, 'internet shopping mall') which small-and-medium sized firms have built, and to provide the general directions of the successful internee-based business for the small-and-medium sized firms. This paper reports the case studies in which the internet-based electronic commerce practices of 6 small-and-medium sized firms were examined over a 3 month period. In the meantime, this paper reports their present business condition, system environment, positioning, marketing strategy, forward business expectation, and market barrier. This study also focuses on two environmental dimensions of system development; One dimension is on-line only or off-line widened, and the other is self-built or outsourcing. The results found in this study are as follows: 1. The internet shopping mall broadens the company's activity to new business areas. 2. The degree of system outsourcing of the small-medium size company depends on its IT ability and resource capability 3. The marketing strategies on their internet shopping mall differentiate with their business area and market environment. 4. Each interviewed company has its own success and failure factors, in addition to the general factors. 5. Each interviewed company has a positive response for their internet shopping mall for its future. 6. The lack of capital, technology, and government support is the barrier to the improvement of the internet shopping mall system.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.263-271
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• 2017

The application of mass spectrometry to polymer science has rapidly increased since the development of MALDI-TOF MS. This review summarizes current polymer analysis methods using MALDI-TOF MS, which has been extensively applied to analyze the average molecular weight of biopolymers and synthetic polymers. Polymer sequences have also been analyzed to reveal the structures and composition of monomers. In addition, the analysis of unknown end-groups and the determination of polymer concentrations are very important applications. Hyphenated techniques using MALDI-tandem MS have been used for the analysis of fragmentation patterns and end-groups, and also the combination of SEC and MALDI-TOF MS techniques is recommended for the analysis of complex polymers. Moreover, MALDI-TOF MS has been utilized for the observation of polymer degradation. Ion mobility MS, TOF-SIMS, and MALDI-TOF-imaging are also emerging technologies for polymer characterization because of their ability to automatically fractionate and localize polymer samples. The determination of polymer characteristics and their relation to the material properties is one of the most important demands for polymer scientists; the development of software and instrument for higher molecular mass range (> 100 kD) will increase the applications of MALDI-TOF MS for polymer scientists.