7,280 research outputs found

    Surface Polaron Formation in the Holstein model

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    The effect of a solid-vacuum interface on the properties of a strongly coupled electron-phonon system is analyzed using dynamical mean-field theory to solve the Holstein model in a semi-infinite cubic lattice. Polaron formation is found to occur more easily (i.e., for a weaker electron-phonon coupling) on the surface than in the bulk. On the other hand, the metal-insulator transition associated to the binding of polarons takes place at a unique critical strength in the bulk and at the surface.Comment: 5 pages, 3 figure

    Design of Finite-Length Irregular Protograph Codes with Low Error Floors over the Binary-Input AWGN Channel Using Cyclic Liftings

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    We propose a technique to design finite-length irregular low-density parity-check (LDPC) codes over the binary-input additive white Gaussian noise (AWGN) channel with good performance in both the waterfall and the error floor region. The design process starts from a protograph which embodies a desirable degree distribution. This protograph is then lifted cyclically to a certain block length of interest. The lift is designed carefully to satisfy a certain approximate cycle extrinsic message degree (ACE) spectrum. The target ACE spectrum is one with extremal properties, implying a good error floor performance for the designed code. The proposed construction results in quasi-cyclic codes which are attractive in practice due to simple encoder and decoder implementation. Simulation results are provided to demonstrate the effectiveness of the proposed construction in comparison with similar existing constructions.Comment: Submitted to IEEE Trans. Communication

    Lowering the Error Floor of LDPC Codes Using Cyclic Liftings

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    Cyclic liftings are proposed to lower the error floor of low-density parity-check (LDPC) codes. The liftings are designed to eliminate dominant trapping sets of the base code by removing the short cycles which form the trapping sets. We derive a necessary and sufficient condition for the cyclic permutations assigned to the edges of a cycle cc of length (c)\ell(c) in the base graph such that the inverse image of cc in the lifted graph consists of only cycles of length strictly larger than (c)\ell(c). The proposed method is universal in the sense that it can be applied to any LDPC code over any channel and for any iterative decoding algorithm. It also preserves important properties of the base code such as degree distributions, encoder and decoder structure, and in some cases, the code rate. The proposed method is applied to both structured and random codes over the binary symmetric channel (BSC). The error floor improves consistently by increasing the lifting degree, and the results show significant improvements in the error floor compared to the base code, a random code of the same degree distribution and block length, and a random lifting of the same degree. Similar improvements are also observed when the codes designed for the BSC are applied to the additive white Gaussian noise (AWGN) channel

    Exploring Successful International Human Resource Management: Past, Present, and Future Directions

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    Today, approximately 60,000 multinational enterprises (MNEs) employ more than 45 million people worldwide. This is about twice as many as in 1990, and this number is predicted to increase to 75 million people by 2010 (Schuler, 2003). This paper is dedicated to helping develop the understanding and competencies necessary for HR managers to succeed. Additionally, this paper aims to review the most important aspects of International Human Resource Management, (IHRM), such as the development of IHRM, IHRM vs. domestic HRM, successful localization, and talent management in IHRM. Finally this paper discusses issues that are likely to gain importance in the IHRM field in the near future.IHRM, HRM, Localization, Talent Management, IHRM Future

    Literature Review of The Store Windows Display Influences on Consumers Attractiveness Through the Layout Design

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    Windows display is one of the important aspect in retail design in order to increase consumer product awareness. The store windows design had been varied especially with the creative visual merchandiser in managing a visual approach of store windows display. Flat type store windows display often used in Bandung Retail, and has characteristic of its own retail brand image to improve attractiveness. Layout design of a store windows display has an important role for the influence of consumer behavior especially in shopping attitudes. This research identify the effects of WAKAI and MANGO store windows display at Trans Studio Mall on consumer attractiveness through the implementation of layout design principles Keywords Store Windows, Retail, Attractiveness, Layout design
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