• Journal of Institute of Control, Robotics and Systems
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• v.8 no.12
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• pp.991-997
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• 2002

The concept of feasible & invariant region plays an important role to derive closed loop stability and achie adequate performance of constrained receding horizon predictive control. In this paper, we define a complex polyhedral feasible & invariant set for all stabilizable input-constrained linear systems by using a complex transform and propose a one-norm based receding horizon control scheme using these invariant sets. In order to get a larger stabilizable set, a convex hull of invariant sets which are defined for different state feedback gains is used as a target invariant set of the constrained receding horizon control. The proposed constrained receding horizon control scheme is formulated so that it can be solved via linear programming.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.81-86
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• 2008

The paradigm of information & communication is rapidly changed into ubiquitous environment based electromagnetic wave, and antenna technology in the wireless ubiquitous communication is remarkably developed. Mini chip antenna has its within small card compared to the external AP antenna. Designed and Fabricated WLAN antenna has a broadband characteristics of 2.4~2.5GHz and 4.9~5.85GHz, and can be used triple mode of IEEE 802.11.a,g.b, and it has comparatively a constant performance in the dual frequency band.

• Journal of the Korean association of regional geographers
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• v.9 no.4
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• pp.505-518
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• 2003

The purpose of this paper is to review Post-Fordist urban economic theories that have tackled the recent changes of urban economies in large cities in the world since 1980s, so that we can conceptualise the changes of urban economies in Korean cities. In the perspective of the Post-Fordist urban economic theories, the recent changes of urban economies in the world are deeply related to the transformation of capitalist world economic system from Fordism to Post-Fordism. To see these changes which can be called as the new urbanization process in the economic aspect, we will focus especially such theories as new industrial space (district) theory based on the flexible specialization paradigm, informational city theory based on the information and communication mode paradigm, and cluster and regional innovation theory based on the institution and network paradigm. Also we will consider the social polarization process and dual city phenomena that have been observed for the most part of big cities in the world.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.36-36
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• 2013

Globular clusters (GCs) are among the oldest stellar objects in the universe and provide valuable constraints on many aspects of galaxy evolution. GC systems typically exhibit bimodal color distributions the phenomenon of which has been a major topic in the area of GC research. GC color bimodality established a paradigm where scenarios to explain its origin require two GC groups with different formation origins. The GC division, asserted mainly by photometric color bimodality so far, has been viewed as the presence of two distinct metallicity subgroups within individual galaxies. In this study, we make use of spectroscopy of GC systems associated with two giant galaxies, M31 (the Andromeda) and M87 (NGC 4486), to investigate the GC bimodality and the underlying metallicity distributions. Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Given that spectroscopy is a more detailed probe into stellar population than photometry; the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We present spectra of 130 old globular clusters (GCs) associated with the Virgo giant elliptical galaxy M87, obtained using the Multi-Object Spectrography (MOS) mode of Faint Object Camera and Spectrograph (FOCAS) on the Subaru telescope. M87 GCs with reliable metallicity measurements exhibit significant inflection along the color-metallicity relations, through which observed color bimodality is reproduced from a broad, unimodal metallicity distribution. Our findings lend further support to this new interpretation of the GC color bimodality, which could change much of the current thought on the formation of GC systems and their host galaxies.