• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.1
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• pp.5-12
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• 2000

As a semiconductor material for electronic devices operated under extreme environmental conditions, silicon carbides (SiCs) have been intensively studied because of their excellent electrical, thermal and other physical properties. The growth characteristics of single- crystalline 6H-SiC homoepitaxial layers grown by a thermal chemical vapor deposition (CVD) were investigated. Especially, the successful growth condition of 6H-SiC homoepitaxial layers using a SiC-uncoated graphite susceptor that utilized Mo-plates was obtained. The CVD growth was performed in an RF-induction heated atmospheric pressure chamber and carried out using off-oriented ($3.5^{\circ}$tilt) substrates from the (0001) basal plane in the <110> direction with the Si-face side of the wafer. In order to investigate the crystallinity of grown epilayers, Nomarski optical microscopy, transmittance spectra, Raman spectroscopy, XRD, Photoluninescence (PL) and transmission electron microscopy (TEM) were utilized. The best quality of 6H-SiC homoepitaxial layers was observed in conditions of growth temperature $1500^{\circ}C$ and C/Si flow ratio 2.0 of $C_3H_8$ 0.2 sccm & $SiH_4$ 0.3 sccm.

• Journal of Hydrogen and New Energy
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• v.29 no.5
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• pp.450-457
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• 2018

To design the practical core-shell electrocatalysts, combination of core and shell materials is important to meet catalytic activity and durability target. In general, Pd is considered as a good core material due to its best activity caused by strain/ligand effect. Preparing Pd nanoparticles can be a starting point in fabricating core-shell type electrocatalysts, much simplified Pd preparing process is suggested by using carbon monoxide (CO) as a reducing agent and/or capping agent. The solvent composition and reaction temperature can control to nanosheet, tetrahedron, and sphere without using additional stabilizer. Among them, Pd nanosheet which has mainly (111) plane showed about 3 times higher electrocatalytic activity for oxygen reduction reaction (ORR) to the spherical Pd nanoparticles. The enhanced ORR activity of Pd nanosheets can be attributed to the exposure of Pd (111) surface and the high electrochemical surface area. Therefore, we demonstrated that the shape of Pd nanomaterials is easily controlled via a facile reduction method using CO, and (111) plane-oriented Pd nanosheets can be a promising ORR catalysts and core material for polymer electrolyte fuel cells (PEFCs).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2737-2746
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• 2010

Recently, Logistics industry has emerged a new u-logistics paradigm combines USN / RFID technology. In this paper offers a vehicle history Web-based logistics management system based on the u-logistics paradigm. The design of this system is considered all events processes as a form of recycling and entire system is to modeling based UML of object oriented. Also It was undergone some process to make sure by logistics vehicles identified that RFID based was identified vehicle logistics. To identify logistics vehicle based RFID, identified the logistics vehicles is a process that will determine. The implementation method designed the interface based web which uses in the manager to C/S methods, consideration of the mobility of the system user implements the user GUI based PDA. As well as, In this paper was separated customer, manufacturer, distributor, administrator, drivers, respectively and focuses to raise a system reusability which is implementation by separately for each feature.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.673-676
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• 2017

The Offshore drilling system of domestic drilling systems (drill rigs, drill ship) in Korea is dependent on full imports and the monopolistic situation of a few foreign large corporations is intensifying. In addition, most of domestic technology development tries to develop single product oriented products until now, but it is necessary to develop monitoring control system for package unit commercialization by approaching package development method. Therefore, we will develop a control monitoring system that can integrate the single equipment of the mud system developed previously.

• The KIPS Transactions:PartD
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• v.8D no.3
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• pp.233-240
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• 2001

As software technology is in progress and software quantification is getting more important, many metrics have been proposed to quantify a variety of system entities. These metrics can be classified into two different forms : scalar metric and metric vector. Though some recent studies pointed out the composition problem of the scalar metric form, many scalar metrics are successfully used in software development organizations due to their practical applications. In this paper, it is concluded that hybrid metric form weighting external complexity is most suitable for scalar metric form. With this concept, a general framework for hybrid metrics construction independent of the development methodologies and target system type is proposed. This framework was successfully used in two projects that quantify the analysis phase of the structured methodology and the design phase of the object oriented real-time system, respectively. Any organization can quantify system entities in a short time using this framework.

• The KIPS Transactions:PartD
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• v.15D no.4
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• pp.569-580
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• 2008

Web services are the current most promising technology for service oriented architecture(SOA) implementations. However, in spite of the large scale acceptance of web services, they have been relegated to internal integration projects, and the grand vision of virtual enterprises where partners can be integrated on demand is yet to be realized. The main reason is that the current standards of web services are not very suitable for the dynamic web service discovery and integration. In this paper, we present a novel SemanticBPEL solution that merges the benefit of WS-BPEL, with the advantage of OWL-S for building a semi-automatic web service composition system. In particular, this work proposes a multi-phase search method for solving dynamic discovery and integration problems of web services. The proposed method is compared with the existing keyword based retrieval method. These comparisons show that our approach outperforms the existing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.1
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• pp.58-70
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• 1990

This paper describes a VLSI implementation of real-time two dimensional DCT processor for the subprimary rate video codec system. The proposed architecture exploits the parallelism and concurrency of the distributes architecture for vector inner product operation of DCT and meets the CCITT performance requirements of video codec for full CSIF 30 frames/sec. It is also shown that this architecture satisfies all the CCITT IDCT accuracy specification by simulating the suggested architecture in bit level. The efficient VLSI disign methodology to design suggested architecture is considered and the module generator oriented design environments are constructed based on SUN 3/150C workstation. Using the constructed design environments. the suggensted architecture have been designed by double metal 2micron CMOS technology. The chip area fo designed 8x8 2-D DA-DCT (Distributed Arithmetic DCT) processor is about 3.9mmx4.8mm.

• Journal of Digital Convergence
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• v.8 no.2
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• pp.217-228
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• 2010

There are two streams on e-Learning. The first one is to create new value through aligning products included information systems and service. The second one is to utilize the service system and the service process for service systematization. The service system is made up human, technology, value proposition, service network, and shared information. The service process consists of design, development, operation and evaluation phases. In this paper, we design and implement the evaluation management of e-learning service based on the service science. The evaluation management service is sets of evaluation type management, general review management, award management, evaluation sheet management and evaluation result management. Feature of this paper is that we can service with different criteria to learner, guardian and evaluator. The worthy of this paper is that we construct service oriented environment possible to systematize evaluation work easily and provide evaluation results clearly.

• Spatial Information Research
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• v.22 no.6
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• pp.13-21
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• 2014

This study defines concept and service framework of Geo-Spatial Big Data(GSBD). The major concept of the GSBD is formulated based on the 7V characteristics: the general characteristics of big data with 3V(Volume, Variety, Velocity); Geo-spatial oriented characteristics with 4V(Veracity, Visualization, Versatile, Value). GSBD is the technology to extract meaningful information from Geo-spatial fusion data and support decision making responding with rapidly changing activities by analysing with almost realtime solutions while efficiently collecting, storing and managing structured, semi-structured or unstructured big data. The application area of the GSBD is segmented in terms of technical aspect(store, manage, analyze and service) and public/private area. The service framework for the GSBD composed of modules to manage, contain and monitor GSBD services is suggested. Such additional studies as building specific application service models and formulating service delivery strategies for the GSBD are required based on the services framework.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.216-227
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• 2005

The head penetrations for control rod drive mechanism and instrumentation systems are installed at the reactor pressure vessel head of PWRs. Primary coolant water and the operating conditions of PWR plants can cause cracking of these nickel-based alloy through a process called primary water stress corrosion cracking (PWSCC). Inspection of the head penetrations to ensure the integrity of the head penetrations has been interested since reactor coolant leakages were found at U. S. reactors in 2000 and 2001. The complex geometry of the head penetrations and the very low echo amplitude from the fine, multiple flaws due to the nature of the see made it difficult to detect and size the flaws using conventional pulse-echo UT methods. Time-of-flight-diffraction technique, which utilizes the time difference between the flaw tips while pulse-echo does the flaw response amplitude from the flaw, has been selected for this inspection for it's best performance of the detection and sizing of the head penetration see flaws. This study defines the limits of the detectable and accurately sizable minimum flaw size which can be detected by the General TOFD and the Delta TOFD techniques for circumferentially and axially oriented flaws respectively. These results assures the reliability of the inspection techniques to detect and accurately size for various kind of flaws, and will also be utilized for the future development and qualifications of the TOFD techniques to enhance the detecting sensitivity and sizing accuracy of the flaws of the reactor head penetrations in nuclear power plants.