• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.3
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• pp.273-288
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• 2010

In this paper, we propose a cooperative multi-relay scheme for a secondary system to achieve spectrum access along with a primary system. In the primary network, a primary transmitter (PT) transmits the primary signal to a primary receiver (PR). In the secondary network, N secondary transmitter-receiver pairs (ST-SR) selected by a centralized control unit (CCU) are ready to assist the primary network. In particular, in the first time slot, PT broadcasts the primary signal to PR, which is also received by STs and SRs. At STs, the primary signal is regenerated and linearly combined with the secondary signal by assigning fractions of the available power to the primary and secondary signals respectively. The combined signal is then broadcasted by STs in a predetermined order. In order to achieve diversity gain, STs, SRs and PT will combine received replicas of the primary signal, using selection combining technique (SC). We derive the exact outage probability for the primary network as well as the secondary network. The simulation results are presented to verify the theoretical analyses.

• Journal of Educational Research in Mathematics
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• v.13 no.2
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• pp.143-157
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• 2003

This paper is to make strides toward an enriched understanding of mathematics teacher learning and professional development. Different theoretical frameworks in understanding mathematics teacher learning are reviewed, followed by a discussion of the relationships of knowledge and teaching practice. This paper then analyses contemporary conceptions about effective professional development and, in particular, deals with teacher learning in inquiry communities. This paper introduces a research project describing transition processes from teacher- centered mathematics classroom culture to student-centered culture and analyzing teacher learning in communities and its concomitant change in teaching practice. On the basis of the emerging problems in doing the project, this paper finally addresses some crucial issues on teacher learning and professional development, including the management of an inquiry community, the description of teaching practice from the researcher's perspective, and the analysis of teacher learning in communities.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.3
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• pp.221-230
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• 2000

The usefulness and limitations of the impact-resonance method, which is a nondestructive evaluation (NDE) method for concrete, are studied by both experimental and theoretical methods. For the experimental study, several concrete slab specimens with various inclusions embedded were fabricated, and tested by the impact-resonance method. Some of the inclusions have been detected and accurately located, but some have not. The reasons for the failure in the latter cases have been investigated theoretically by using finite element analyses, from which the primary factors determining the success of the method have also been identified. This study will serve to enhance the understanding of the underlying physics and to improve the usefulness of the impact-resonance method as applied to concrete NDE.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.109-115
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• 2004

Polishing process has been applied to get extremely fine surfaces, e.g., mirror surfaces such as optical mirrors, lens, molds and etc. Nowadays not only fine surface quality but also submicron order of dimensional accuracy is required for many applications. To meet the requirements polishing process should be provided with an active control of polishing pressure especially for automation of polishing process. In this paper a study on development of an active polishing pressure control system has been presented. A new type of tool assembly has been developed to facilitate the control. The tool is attached to an axis of a polishing machine with a coil spring and control of the polishing pressure is done by the position control of the axis, which needs no additional actuator. The polishing pressure is successfully measured by the measurement of the spring deformation. Control specifications were quantitatively considered by weighting functions and a controller was designed by using loop-shaping technique based on the no synthesis. Some experiments have been executed on a polishing machine with a PC-NC controller. It is shown that the results were coincident well with the theoretical analyses and satisfied the design specifications.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.102-107
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• 2006

In Japan, research and development were undertaken on gas hydrate-side industrial processes associated with power generation system connections that may particularly be necessary to develop gas hydrated technology-based industrial systems. In so doing, data and engineering technologies useful n formulating guidelines on design of practical process were accumulated. In addition, basic research into theoretical evidence were carried out to promote and support the development of technological elements for those processes. In basic research designed to promote and support the research and development of elemental technologies, microanalyses were conducted to understand the decomposition mechanism of mixed gas hydrate. Moreover, measurement technologies that can be applied in industrial processes, such as numerical analyses and concentration measurement, were examined. Japan has developed a highly efficient gas hydrate formation process using micro-bubbles with a tubular reactor. Higher formation rate over conventional systems has been obtained by the process. As mentioned above, the technical problems were clarified and the economics were studied from a view point of the NGH technology in this study. The results can be applied for utilization and must contribute to popularization of gas hydrate production.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.80-88
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• 2011

It is no simple matter to measure and manage the quality of Software which is invisible. However the importance cannot be ignored as the software development project is getting bigger and complex. This study analyses and compares the methods of software quality improvement. Further it formulates rules for Code Inspection and verifies the efficiency and the effectiveness by applying to practical project. The study get the following results. First, the study organizes theoretical content about the methods of Software review. Second, the study formulates rules for Code inspection and demonstrates the result through the case study. Third, the study performs the quantitative dater management through code inspection.

• Journal of the Korea Fashion and Costume Design Association
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• v.18 no.3
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• pp.145-163
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• 2016

This paper analyses Wassily Kandinsky's abstract paintings. this paper aims to discuss phases of Kandinsky's works as well as their formative characteristic theory. Practically, with formative characteristics in Kandinsky's paintings such as point, line, plane, form and color, this paper presents four sets of costumes. Among which, geometric patterns are intensively collaged as the formative characteristic of "point" calls for; crossed necklines and waistlines are applied as the characteristic of "lines" represents; plane and solid patterns are adopted as the main parts and ornaments as both the characteristic of "plane" and that of "form" claim; three primary colors - red, blue and yellow - are introduced as the characteristic of "color" depicts. Artificial leathers are used as the main fabric, patchwork and draping as so in technology. Therefore, with the theoretical and practical efforts, this paper aims to seek the interdisciplinary possibilities between paintings and fashion arts, and in order to develop several fashion designs representing modern aesthetics with their unique characteristics.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.161-168
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• 2010

A city is a type of culture as living styles people have accumulated, In Particular, urban streets are integrated bodies of culture based on regional history and tradition which are easily accessible by people. However, due to insensible expansion policy of current cities, decline of old downtowns which have kept cultural characteristics of each region, hollowing out of the downtowns, expansion of new downtowns which have uniformed characteristics are weakening identities of each region. To overcome such problems, a culture-oriented approach as one of the urban regeneration strategies which have been appeared since 1980s is effective. Life style which has been formed by human activities can be considered as the culture of comprehensive concept and peculiar resources of each region are distinctive culture of each region. Cultural streets in which people can share each other's feeling may influence regional activation through cultural influence while preserving regional tradition and history. Therefore, this study aims to discover spatial characteristics of cultural streets through theoretical examinations on formation of streets in as aspect of urban regeneration and identify their characteristics by analyzed cases of domestic cultural streets.

• Journal of Power Electronics
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• v.10 no.5
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• pp.505-517
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• 2010

In this paper, an intelligent sliding-mode speed controller for achieving favorable decoupling control and high precision speed tracking performance of permanent-magnet synchronous motor (PMSM) drives is proposed. The intelligent controller consists of a sliding-mode controller (SMC) in the speed feed-back loop in addition to an on-line trained wavelet-neural-network controller (WNNC) connected in parallel with the SMC to construct a robust wavelet-neural-network controller (RWNNC). The RWNNC combines the merits of a SMC with the robust characteristics and a WNNC, which combines artificial neural networks for their online learning ability and wavelet decomposition for its identification ability. Theoretical analyses of both SMC and WNNC speed controllers are developed. The WNN is utilized to predict the uncertain system dynamics to relax the requirement of uncertainty bound in the design of a SMC. A computer simulation is developed to demonstrate the effectiveness of the proposed intelligent sliding mode speed controller. An experimental system is established to verify the effectiveness of the proposed control system. All of the control algorithms are implemented on a TMS320C31 DSP-based control computer. The simulated and experimental results confirm that the proposed RWNNC grants robust performance and precise response regardless of load disturbances and PMSM parameter uncertainties.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.149-158
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• 2010

This study is a comparative analysis of the creation and development of visual techniques used in girls' comics in the paradigmatic low and high-context cultures of American and Japan. As previous analyses have shown, there are qualitative differences in the expressive mechanisms employed in girls' comics in Eastern and Western cultures, and it is an investigation of this realm of expression that is the basis of this study. Particular emphasis is placed on an analysis of the structure of frames, one of the most fundamental expressive mechanisms in girls' comics. A close examination of this underlying structural component reveals that both cultures demonstrate autonomous growth, providing a theoretical framework for future studies.