• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.505-512
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• 1994

It has been reported that a biocement obtained by mixing CaO-SiO2-P2O5 glass powder and ammonium phosphate solution has biocompatibility as well as high strength. However, the compositional dependence on its hardening and hydroxyapatite formation phenomena has not been studied. Therefore, the main objective of this work is to study the effects of P2O5, MgO in CaO-SiO2 system glass on the hardening and hydroxyapatite formation. When more than 50 mole% of CaO containing CaO-SiO2 glasses was reacted with ammonium phosphate solution, CaNH4PO4.H2O crystal was formed, but the glass with less than 50 mol% of CaO formed (NH4)2HPO4 and NH4H2PO4 crystals which are derived from ammonium phosphate solution without reacting with the glasses. As the amount of P2O5 in CaO-SiO2-P2O5 glass system was increased, the formation of CaNH4PO4.H2O crystal was enhanced. When those hardened samples were reacted with tris-buffer solution, hydroxyapatite was obtained only for the sample with CaNH4PO4.H2O. While the substitution of MgO for CaO decreased the formation of CaNH4PO4.H2O crystal. MgNH4PO4.H2O crystla was formed in high MgO containing glass, which did not react with tris-buffer solution.

• Journal of the Ergonomics Society of Korea
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• v.25 no.2
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• pp.125-134
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• 2006

Most users learn new, complex systems through trial-and-error experience rather than referring to the manuals in a cognitive process that is called 'exploratory learning'. While exploring a system, people find prototypical rules for using the system based especially on frequent tasks. The rules are formed from consistent task procedures and well-expected interface elements on the designed system. These rules play the role of the basis of users' knowledge for performing tasks. The decision making to select and apply those rules interacting with an interface can be aided by properly provided hints on the interface. With appropriate hints, users can learn new systems easily and use them with reduced usability problems. This paper first reports an observation of user behavior performing tasks with prototypical interaction rules and finds a sound set of criteria to extract prototypical interaction rules systematically. Two types of hints are defined. Extending hints prompt users to apply prototypical interaction rules beyond well-known tasks. Preventive hints guide users out of possible capture errors by drawing attention to the variation of rules. A systematic and practical method is proposed to identify the opportunities for both types in designing interfaces. It is then verified through a usability test that the proposed method is effective in identifying the locations and types of appropriate hints to reduce or mitigate usability problems.

• Journal of Information Technology Applications and Management
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• v.20 no.2
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• pp.69-87
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• 2013

The expanded spiral model in this paper consists of five processes of architecture design, architectural construction, architectural maintenance, operation, and architectural management. The former four processes are executed alternatively, while the latter architectural management process is executed continuously interacting with the other processes during the whole life cycle of the system. The expanded spiral model provides a conceptual framework to sort discussions of architectural degeneration into those of product-oriented processes and those of management processes, making it possible to incorporate the models and body of knowledge about project and program management especially those of Project Management Institute, into discussions of architectural degeneration. A good architecture decomposes the software-intensive system into components mutually interacting in a well-formed structure. The architecture design process and the architectural construction process together create the object system with well-designed architecture. The architectural maintenance process prevents the implemented architecture deviate from the designed architecture. The architectural management process monitors the changes of requirements including architecturally significant requirements, supports the other processes to be executed reflecting various perspectives of stake-holders, and creates and documents the reasons of architectural decisions, which is considered as a key element of the architecture.

• Earthquakes and Structures
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• v.7 no.6
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• pp.955-967
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• 2014

Storage racks are used worldwide in industries and commercial outlets due to the advantage of lighter, faster erection and easy alteration of pallet level as required. The studies to understand the behaviour of cold formed steel pallet racks, under seismic action is one of the emerging area of research. The rack consists of perforated uprights and beams with hook-in end connector, which enables the floor height adjustments. The dynamic characteristics of these racks are not well established. This paper presents the dynamic characteristics of 3-D single bay two storey pallet rack system with hook-in end connectors, which is tested on shake table. The sweep sine test and El Centro earthquake acceleration is used to evaluate the seismic performance of the cold formed steel pallet racks. Also an attempt is made to evaluate the realistic dynamic characteristics by using STAAD Pro software. Modal analysis is performed by incorporating the effective moment of inertia of the upright, which considers the effect of presence of perforations and rotational stiffness of the beam-to-upright connection to determine the realistic fundamental frequency of pallet racks, which is required for carrying out the seismic design. Finite element model of the perforated upright section has been developed as a cantilever beam through which effective moment of inertia is evaluated. The stiffness of the hook-in connector is taken from the previous study by Prabha et al. (2010). The results from modal analysis are in good agreement with the respective experimental results.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.275-278
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• 1996

This fault diagnosis system consists of qualitative models, qualitative interpreter, and inference engine. Qualitative models are formed by analysis of the relationships between faults and behaviors of sensor trends, which are described by state transition trees. Qualitative interpreter outputs confidence factors with three qualitative quantities which represent the states of sensor trends. And then, the possible faults are detected by inference module which matches the states of trends within a window size with the qualitative models using the well-known min-max operation.

• Journal of Information Technology Applications and Management
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• v.15 no.3
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• pp.243-259
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• 2008

To support business services interoperation, the BSD (Business Service Document), which is an extension of the Web Service Description Language (WSDL) the web service specification of the World Wide Web Consortium (W3C) was designed. The WSDL presents comprehensive standards for the interoperability of software components and W3C delegates extensions of WSDL to the users for their own purposes and objectives. In this article, BSD Creator, which can generate well-formed and valid BSDs, was designed and implemented. Also, the BSD Operation Pilot System where service providers can publish BSD specification documents and service users can search for services, was implemented and presented. BSD Creator and the BSD Operation Pilot System, which are the outcomes of this study, were assessed for their quality and usefulness using ISO/IEC 9126. The outcomes of this paper will be the basis on which industry groups can construct a Business Services Interoperation System, and are expected to contribute to the revitalization of business service interoperation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.11
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• pp.496-500
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• 2003

A low-cost, large area, random, maskless texturing scheme independent of crystal orientation is expected to significantly impact terrestrial photovoltaic technology. We investigated silicon surface microstructures formed by reactive ion etching (RIE) in Multi-Hollow cathode system. Desirable texturing effect has been achieved when radio-frequency (rf) power of about 20 Watt per one hollow cathode glow is applied for our RF Multi-Hollow cathode system. The black silicon etched surface shows almost zero reflectance in the visible region as well as in near IR region. The etched silicon surface is covered by columnar microstructures with diameters from 50 to 100 nm and depth of about 500 nm. We have successfully achieved 11.7% efficiency of mono-crystalline silicon solar cell and 10.2% multi-crystalline silicon solar cell.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.11
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• pp.3837-3859
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• 2014

Vehicular Ad hoc Networks (VANET) becomes more popular in industry, academia and government. However, Typical VANET is challenged by high speed mobility and insufficient spectrum resources over congested scenarios. To address those serious problems, some articles have introduced Cognitive Radio (CR) technology into VANET and formed CR-VANET. In this article, we propose an overview of CR-VANET by exploring different architectures and features. Moreover, we provide taxonomy of state-of-the-art papers in this emerging field and the key articles are well analyzed respectively. In addition, we illustrate both research and application frameworks of CR-VANET based on our works, and propose some open research issues for inspiring future work.

• Journal of Information Technology Applications and Management
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• v.20 no.3
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• pp.1-18
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• 2013

Software architecture is the blueprint for a software system and should provide consistent guidelines for design, implementation, and maintenance throughout the entire lifecycle of the system. Components, interactions between the components, well-formed structure, reasons, and various perspectives reflecting various stakeholders' concerns changing through the phases of software lifecycle are the key elements of software architecture. The architect identifies and engages the stakeholders, understands and captures stakeholder's concerns including those regarding life cycle, and lets the concerns reflected in the architecture. To do so, architect should take into consideration various contextual elements regarding the system too. We make an extended list of the elements, especially those of business application software architecture, that the architect should take into consideration and construct a model of the relationships between the elements.

• International Journal of Computer Science & Network Security
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• v.22 no.6
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• pp.19-24
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• 2022

The main purpose of the study is to analyze the current state of the organization's information security system in the context of COVID-19 on the basis of public-private partnership. The development of public-private interaction in information security is one of the priorities of the state policy of many estates. Among the priorities of public-private partnership in cybersecurity and information security, there is an expansion of interaction between government agencies and private scientific institutions, public associations and volunteer organizations, including in training, as well as increasing the digital literacy of citizens and the security culture in cyberspace. As a result of the study, the foundations of the organization's information security system in the context of COVID 19 were formed on the basis of public-private partnership.