• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.461-461
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• 2000

We have investigated electronic structuresof antiferromagnetic YBaCo_2O_5 using the local spin-density approximation (LSDA) + U method. The charge and orbital ordered insulating ground state is correctly obtained with the strong on-site Coulomb interaction. Co^{2+} and Co^{3+} ions are found to be in the high spin (HS) and intermediate spin (IS) state, respectively. The tetragonal to orthorhombic structural transition is responsible for the ordering phenomena and the spin states of Co ions. The large contribution of the orbital moment to the total magnetic moment indicates that the effect of the spin-orbit coupling is very important in YBaCo_2O_5.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.11-11
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• 2010

Supramolecualr ordering has been actively studied due to it's possible applications to the fabrication processes of nano-electronic devices. Van der Waals interaction and hydrogen bonding are frequently studied mechanisms for various molecular structures based on non-uniform charge distributions. Halogen atoms in molecules can have electrostatic interactions with similar strength. Big halogen atoms have strong non-uniform charge distributions. To study molecular orderings formed by hydrogen and halogen interactions, we chose a molecular system containing oxygen, hydrogen, and bromine atoms, a bromo-quinone. A two-dimensional molecular network was studied on Au(111) using a low-temperature scanning tunneling microscope. Bromo-quinonemolecules form self-assembled square grids having windmill structures. Their molecular orderings, chiral structures, and defects are explained in terms of hydrogen and halogen interactions.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.796-806
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• 2008

This paper presents a blind video watermarking algorithm that has the robustness against spatial, temporal, and SNR scalability and transcoding for the copyright protection of video contents in heterogeneous multimedia service. The proposed process of watermark embedding and detecting is accomplished on base layer for considering spatial scalability. The watermark consists of the string and the ordering number of string for considering temporal scalability. Thus, each of frames has the bitstream of one character and a ordering number of its character. To robust against FGS, the proposed algorithm quantizes low and middle frequency coefficients in ROI region of each of frames and embeds its watermark bitstream into the specific bits of the quantized coefficients. Experimental results verified that the proposed algorithm satisfies the invisibility of watermark and also has the robustness against spatial scalability, temporal scalability and FGS.

• Bulletin of the Korean Chemical Society
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• v.15 no.1
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• pp.64-74
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• 1994

The nonstoichiometric chalcogenides with NaCl-type structure were prepared and the physical and structural properties were studied. The homogeneous range and the structural change were studied based on X-ray powder diffractions using Rietveld-type full-profile fitting technique. Wide homogeneous ranges were observed in Y-S and Y-Se systems, and relatively narrow homogeneous ranges were observed in Yb-S and Yb-Se systems. Both in $Yb_{1-x}S\;and\;Yb_{1-x}Se$, a vacancy ordering transition occurred in (111) plane direction. The ordered superstructure had cubic symmetry(Fm$\bar{3}m) with doubled unit cell "a" parameter compared to the original NaCl-type. The superlattice developed in a continuous second-order transitiion was characterized by the reduced waved vector k= $(a^*+b^*+c^*)/2$. Y-S system had metallic, and YSe, YbSe system had semiconducting properties in their homogeneous ranges. It was observed that the change of electronic transport properties in extended homogeneous range did not depend on the relativeratio of metal to nonmetal, but on the quantities of vacancies.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.12-15
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• 2006

We present the structural, magnetic, and electrical properties in the (Al,Mn)N films with various Mn concentrations grown by plasma-enhanced molecular beam epitaxy. X-ray diffraction analyses reveal that the (Al,Mn)N films have the wurtzite structure without secondary phases. All (Al,Mn)N films showed the ferromagnetic ordering. Particularly, ($Al_{1-x}Mn_{x}$)N film with x = 0.028 exhibited the highest magnetic moment per Mn atom at room temperature. Since all the films exhibit the insulating characteristics, the origin of ferromagnetism in (Al,Mn)N might be attributed to either indirect exchange interaction caused by virtual electron excitations from Mn acceptor level to the valence band within the samples or a percolation of bound magnetic polarons arisen from exchange interaction of localized carriers with magnetic impurities in a low carrier density regime.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.104-106
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• 2003

In this study, the electronic structures and physical properties of Ni$_2$MnGa alloy films and their dependence on the order-disorder structural transitions were investigated. The results show that the ordered films behave nearly the same as the bulk $Ni_2$MnGa alloy, including the martensitic transformation at 200 K. Unexpectedly, the disordering in $Ni_2$MnGa alloy films does not lead to any appreciable magnetic ordering down to 4 K. An annealing of the disordered films restores the ordered structure with an almost full recovery of the magnetic and the transport properties of the ordered $Ni_2$MnGa alloy films. A possible explanation of the disappearance of magnetic moment in the disordered film is given by using the ab initio first-principles electronic-structure calculations.

• The Journal of Information Systems
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• v.26 no.3
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• pp.295-312
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• 2017

Purpose Consumption behaviors of consumers have changed with the widespread use of the Internet and smart phones, and accordingly online marketing activities are becoming ever more prevalent. Yet, the domestic food-service industry has yet to offer an Omni-Channel order system that encompasses a online, offline, and mobile interface. Also, a multilingual menu ordering service for foreign tourists is not yet available. Therefore, if an order service system accessible online and offline which could provide multi-language services were implemented, the satisfaction of the service provider and domestic and foreign customers would be maximized. Design/methodology/approach By designing an electronic menu based on open an OS and providing electronic menus in offline stores, we have completed the design of a linked order system which would be available everywhere (online, offline, and mobile). The CMS was developed to integrate these three mediums and the entire operator was designed to receive basic information and statistical information about the merchants, or store operators. Also, a multilingual term dictionary containing menu information for foreign tourists was made into a database so that foreign tourists who are having difficulty in communication can use it more easily. Findings We have made it possible for customers to use the order service without distinction between online, offline, and mobile platforms, and have proved that it is a more efficient and convenient service for customers as well as operators. Nevertheless, as an initial model, the implemented system has limitations on the execution of the payment support method in the electronic menu board and in the management division of the CMS. In case of commercialization, it is necessary to make an alliance of efforts to attract initial franchises. Through further supplementation, we expect the online and offline connection-types martservice system will maximize the satisfaction of both operators and customers alike.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.56-56
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• 2010

Using first-principles density-functional theory calculations, we find dramatically different electronic states in the C chains generated on the H-terminated C(111) surface, depending on their length and parity. The infinitely long chain has $\pi$ electrons completely delocalized over the chain, yielding an equal C-C bond length. As the chain length becomes finite, such delocalized $\pi$ electrons are transformed into localized ones. As a result, even-numbered chains exhibit a strong charge-lattice coupling, leading to a bond-alternated structure, while odd-numbered chains show a ferrimagnetic spin ordering with a solitonlike structure. These geometric and electronic features of infinitely and finitely long chains are analogous to those of the closed (benzene) and open (polyacetylene) chains of hydrocarbons, respectively.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.103.1-103.1
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• 2008

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.704-709
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• 2007

The purpose of this study is to present both problems and improvement plans on the bidding system of the Korea National Housing Corporation, which orders apartment houses professionally. For data gathering, this study used data from electronic procurement system from 2001 to 2005. The research method of this study is to analyze the data categorized into four types: changes of ordering and contract price ration, the lowest-pricing bidding system, and permanent projects by grades. As a result of the analysis, the amount of ordering is biased in favor of particular level. Finally, this study present following improvement plans: 1) screening system and the lowest-pricing bidding system need to be supplemented, 2) the contract price ratio and the amount of ordering should be controlled, and 3) the improvement of PQ and the introduction of the list of Qualified companies by types need to be presented.