1,834 research outputs found

    Trade liberalization and environmental tax in differentiated oligopoly with consumption externalities

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    This paper investigates the environment tax and trade liberalization with different market structures (pure oligopoly or mixed oligopoly) juxtaposing the substitutability of the goods (homogenous goods and differentiated goods), wherein environmental damage is associated with consumption. It shows that the environmental tax in mixed oligopoly is higher than in pure oligopoly irrespective of the properties of goods. In addition, it demonstrates that when the domestic market increases its openings, the tariff reduction does not always bring positive effects on the environment in mixed oligopoly but, in pure oligopoly with homogeneous goods, the tariff reduction is bad for the environment.

    A DHT-Based Multicarrier Modulation System with Pairwise ML Detection

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    This paper presents a complex-valued discrete multicarrier modulation (MCM) system based on the real-valued discrete Hartley transform (DHT) and its inverse (IDHT). Unlike the conventional discrete Fourier transform (DFT), the DHT cannot diagonalize multipath fading channels due to its inherent properties, and this results in mutual interference between subcarriers of the same mirror-symmetrical pair. We explore this interference pattern in order to seek an optimal solution to utilize channel diversity for enhancing the bit error rate (BER) performance of the system. It is shown that the optimal channel diversity gain can be achieved via pairwise maximum likelihood (ML) detection, taking into account not only the subcarrier's own channel quality but also the channel state information of its mirror-symmetrical peer. Performance analysis indicates that DHT-based MCM can mitigate fast fading effects by averaging channel power gains of each mirror-symmetrical pair of subcarriers. Simulation results show that the proposed scheme has a substantial improvement in BER over the conventional DFT-based MCM system

    Systolic array implementation of Euclid's algorithm for inversion and division in GF(2m)

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    [[abstract]]This paper presents a new systolic VLSI architecture for computing inverses and divisions in finite fields GF(2m) based on a variant of Euclid's algorithm. It is highly regular, modular, and thus well suited to VLSI implementation. It has O(m2) area complexity and can produce one result per clock cycle with a latency of 8m-2 clock cycles. As compared to existing related systolic architectures with the same throughput performance, the proposed one gains a significant improvement in area complexity[[fileno]]2030102030060[[department]]電機工程學

    Novel digit-serial systolic array implementation of Euclid's algorithm for division in GF(2m)

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    [[abstract]]In this paper, a novel digit-serial systolic array for computing divisions in GF(2m) over the standard basis is presented. To the authors' knowledge, this is the very first digit-serial systolic divider for GF(2m). The proposed architecture possesses the features of regularity, modularity, and unidirectional data flow. Thus, it is well suited to be implemented using VLSI techniques with fault-tolerant design. One important feature of the proposed architecture is that different throughput performances can be easily achieved by varying the digit size. By choosing the digit size appropriately, the proposed digit-serial architecture can meet the throughput requirement of a certain application with minimum hardware.[[fileno]]2030102030012[[department]]電機工程學

    A Cross-Layer Design Based on Geographic Information for Cooperative Wireless Networks

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    Most of geographic routing approaches in wireless ad hoc and sensor networks do not take into consideration the medium access control (MAC) and physical layers when designing a routing protocol. In this paper, we focus on a cross-layer framework design that exploits the synergies between network, MAC, and physical layers. In the proposed CoopGeo, we use a beaconless forwarding scheme where the next hop is selected through a contention process based on the geographic position of nodes. We optimize this Network-MAC layer interaction using a cooperative relaying technique with a relay selection scheme also based on geographic information in order to improve the system performance in terms of reliability.Comment: in 2010 IEEE 71st Vehicular Technology Conference, 201

    Evaluation of Site Response Using Downhole Array Data from a Liquefied Site

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    Downhole array ground motions recorded at Port Island during the mainshock and aftershocks of the Hyogoken-Nanbu (Kobe) earthquake of January 17, 1995, were used in this study for evaluating the reasonableness of commonly used site response analysis techniques (both nonlinear effective stress and equivalent linear total stress techniques). The nonlinear effective stress analyses were performed using the computer code SUMDES; the equivalent linear total stress analyses were performed using the computer code SHAKE. Dynamic soil properties as well as other data for characterizing nonlinear stress-strain, cyclic strength, and pore pressure generation and dissipation of the Masado till that liquefied during the mainshock of the Kobe earthquake were derived from published papers

    Hypoxia-inducible factor-1α regulates matrix metalloproteinase-1 activity in human bone marrow-derived mesenchymal stem cells

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    AbstractWe examined the mRNA levels of hypoxia-inducible factor-1α (HIF-1α) in bone marrow mesenchymal stem cells (bmMSCs) of eight osteoarthritis patients. BmMSC-1, expressing higher HIF-1α mRNA and protein than bmMSC-5, elicited higher matrix metalloproteinase-1 (MMP1) activity and stronger invasive capacity. In vitro invasion assays and quantitative PCR analyses showed that targeted inhibition of HIF-1α in bmMSC-1 decreased its invasion and expressions of MMP1 and MMP3, whereas overexpression of HIF-1α in bmMSC-5 increased its invasion and expressions of MMP1 and MMP3. Therefore, HIF-1α can regulate MMP1 and MMP3 expressions in human bmMSCs, which might suggest a pathophysiological role of bmMSC expressing high HIF-1α in bone diseases
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