30 research outputs found
A preliminary discussion of Chinese agricultural treatises in the style of "monthly ordinances" yueling
No full textThis article presents and gives an analysis of a special kind of agricultural treatises : yueling ("monthly ordinances"). Beginning with the most ancient texts, the author considers the whole literature still existing on this theme and shows their modern equivalents.Cet article présente et analyse un type de traités d'agriculture, les yueling ("préceptes mensuels"). Partant des ouvrages les plus anciens, l'auteur considère successivement l'ensemble de la littérature existant sur ce thème et en montre les prolongements contemporains.Dong Kaichen. A preliminary discussion of Chinese agricultural treatises in the style of "monthly ordinances" yueling. In: Journal d'agriculture traditionnelle et de botanique appliquée, 28ᵉ année, bulletin n°3-4, Juillet-décembre 1981. pp. 231-251
Exploiting user interaction in interference-aware wireless networks
No full textDue to the shared nature of the wireless media, the wireless users in a network naturally interact with each other and thus a ect the transmissions of each other. The aim of this thesis is to illustrate the crucial role of user interaction in designing effcient interference-aware communication schemes in wireless networks, from both user-centric and network-centric points of view. Specically, this thesis investigates various key issues on exploring wireless user interaction, such as tradeo analysis, co-existence criterion, algorithm complexity, and system capacity characterization, for wireless networks consisting of homogeneous and heterogeneous users, respectively. This thesis also demonstrates the usefulness of two mathematical tools, stochastic geometry and dynamic programming, and shows their effectiveness in designing efficient communication schemes in interference-aware wireless networks. First, in an ad hoc network consisting of homogeneous wireless users, to guide the transmit interaction between users, this thesis proposes a transmission scheme with signal-to-interference-ratio (SIR) threshold based scheduling. This thesis considers a stochastic ad hoc network, where the locations of the transmitters and receivers as well as the channel fading between any transmitter and receiver are randomly distributed. By using tools from stochastic geometry, this thesis focuses on analyzing the effects of user interaction on the ad hoc network capacity. Specifically, this thesis adopts a homogeneous Poisson Point Process (PPP) to model the locations of transmitters that have the intention to transmit. Due to the SIR-threshold based scheduling, it is shown that the resulting point process formed by the transmitters that are allowed to transmit is a non-PPP in general. This thesis tackles the challenges on analyzing the non-PPP based network, by proposing a new method to approximately characterizing the non-PPP network capacity. Such method is useful for analyzing performance of wireless networks with interacted transmitters. Moreover, this thesis reveals the exact/approximate dependence between the system performance and the system designing parameters, which gives designing insights for networks with SIR-threshold based scheduling. Next, in a cognitive radio (CR) network consisting of secondary users (SUs) and primary users (PUs), this thesis assumes that the PUs are able to react to the SU's collision or interference by adapting its transmit power level and/or adjusting its channel access probability. Such PUs are referred to as reactive PUs, to differentiate from their non-reactive counterparts. This thesis proposes a 4-state Markov chain to model the channel occupancy of the reactive PU. Under a practical scenario where the PU's channel occupancy status is only partially known to the SUs, this thesis studies the opportunistic spectrum access (OSA) design for the SU, by adopting two methods to protect the reactive PU's transmission, respectively. One is the conventional short-term conditional collision probability (SCCP) constraint, and the other is a long-term PU throughput (LPUT) constraint. By exploiting a separation principle to separate the SU's channel selection from its spectrum sensor design and channel access decision on the selected channel without loss of optimality, an optimal OSA policy under the SCCP constraint and a suboptimal OSA policy under the LPUT constraint are obtained in this thesis, respectively. It is shown that the conventional SCCP constraint, which is effective in protecting the non-reactive PUs, is not able to properly protect the reactive PUs, while the LPUT constraint can provide sufficient protection for the reactive PU's transmission. Interesting tradeo between SU throughput maximization and PU transmission protection are also revealed in this thesis.DOCTOR OF PHILOSOPHY (EEE
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A History of Style: Literary Criticism in Cold War China
No full textThis dissertation studies the history and methodology of Chinese literary criticism with the aim of understanding the concept of style in literature. Style is an elusive concept in literary studies. Undeniably, readers perceive stylistic differences when they look at different literary texts, to the extent that the author of a text may be identified by those differences alone, which indicates that style is a fundamental property of writing. However, scholars of literature have so far been unable to determine what specific characteristics of a text constitute its style, and therefore cannot reach a consensus on the definition of style. My study aims to relieve the conceptual difficulties surrounding the idea of style and re-introduce style into literary studies.
To this end, rather than directly proposing a new definition of style, this dissertation identifies and examines the ways in which the concept has been used in the history of literary criticism. This dissertation identifies four approaches through which prominent Chinese literary critics of the twentieth century have formulated their opinions about the styles of canonical literary works. The four approaches are named the ideological, the pedagogical, the impressionistic, and the linguistic. Each approach stems from a tradition in the history of literary criticism; each highlights a distinct dimension of the concept of style. Based on case studies of the four approaches, I find that style has primarily been used as a tool for the value judgment of literature, which explains why the concept is indispensable in Chinese literary criticism even without a concrete definition. Style plays an essential role in canon formation.
In addition, this study of style has led to a discovery of the transregional networks that shaped literary criticism in the Cold War era. The first two chapters of the dissertation focus on early Maoist China, and the last two chapters follow a group of intellectuals based in postwar Hong Kong, Taiwan, and the United States. Examining the institutions of literary criticism in those locations and the networks between them, this dissertation illustrates the Soviet influence on Chinese socialist literary theory, on the one hand, and the impact of US public diplomacy on literary studies in Hong Kong and Taiwan, on the other hand. In this period of frequent ideological disagreements, literary critics took advantage of the vagueness of style to criticize the literary works that did not align with their ideology, presenting their judgment of the ideas expressed in a work as if it were an objective description of the inherent quality of that work. In this way, the study of style sheds light on how the Cold War shaped intellectual history globally
Utility-based power control in hierarchical spectrum sharing networks for cognitive radio
No full textA Two-Step Channel and Power Allocation Scheme in Centralized Cognitive Networks Based on Fairness
No full textLand use/cover change effects on floods with different return periods: a case study of Beijing, China
No full textIn this study, an approach integrating digital land use/cover change (LUCC) analysis, hydraulic modeling and statistical methods was applied to quantify the effect of LUCC on floods in terms of inundation extent, flood arrival time and maximum water depth. The study took Beijing as an example and analyzed five specific floods with return periods of 20-year, 50-year, 100-year, 1000-year and 10000-year on the basis of LUCC over a nine-year period from 1996 to 2004. The analysis reveals that 1) during the period of analysis Beijing experienced unprecedented LUCC; 2) LUCC can affect inundation extent and flood arrival time, and floods with longer return periods are more influenced; 3) LUCC can affect maximum water depth and floods with shorter return periods are more influenced; and 4) LUCC is a major flood security stressor for Beijing. It warns that those cities having experienced rapid expansion during recent decades in China are in danger of more serious floods and recommends that their actual land use patterns should be carefully assessed considering flood security. This integrated approach is demonstrated to be a useful tool for joint assessment, planning and management of land and water.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000324231400013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Engineering, EnvironmentalEnvironmental SciencesSCI(E)中国科学引文数据库(CSCD)2ARTICLE5769-776
UAV-Aided Information and Energy Transmissions for Cognitive and Sustainable 5G Networks
No full textTo develop sustainable fifth generation (5G) wireless networks and utilize the unused spectrum, this paper focuses on cognitive radio (CR) based wireless information and energy transmissions from an unmanned aerial vehicle (UAV) to multiple low-power ground terminals (GTs). By practically considering the location-dependent air-to-ground (A2G) channel states and the non-linear energy harvesting (EH), we propose a dynamic fly-hover-transmit scheme, where the UAV successively flies between GTs, and hovers close to each GT for efficient wireless energy transfer (WET) or wireless information transfer (WIT) when the primary user (PU) is idle. By causally and optimally determining the UAV's mobility and transmit power for each selected transmission mode (WIT, WET, or being silent), we formulate the UAV's sum-throughput maximization over all GTs as a constrained Markov decision process (MDP) problem with battery energy constraints at all GTs and the UAV. Due to the infinitely large MDP system state space, this problem is difficult to solve. We then decompose this problem into two subproblems, by first deciding the UAV's transmission mode and power above a given GT, and then optimizing the UAV movement policy over multiple GTs. In the first subproblem, we propose an approximate to the complicated MDP value function of low complexity in closed-form, and then analytically derive the threshold-based suboptimal transmission policies. In the second subproblem, we optimally solve a simple-but-fundamental two-GT case, and then extend the general location-dependent GT weight design to an efficient suboptimal UAV movement policy. Simulation results show the significantly improved system performance under the proposed suboptimal policies over various benchmarks in dynamic networks.</p
ϒ(nS)→Bcρ, BcK⁎ decays with perturbative QCD approach
No full textAbstractInspired by the potential prospects of ϒ(nS) data samples (n=1,2,3) at LHC and SuperKEKB, ϒ(nS)→Bcρ, BcK⁎ decays are studied phenomenologically with pQCD approach. Branching ratios for ϒ(nS)→Bcρ and BcK⁎ decays are estimated to reach up to O(10−11) and O(10−12), respectively. Given the identification and detection efficiency of final states, searching for these weak decay modes should be fairly challenging experimentally in the future
Uncertainty and corporate R & D investment: Evidence from Chinese listed firms
No full textUsing data from Chinese listed firms, this paper studies the effects of policy and market uncertainties on corporate R & D investment. The empirical findings indicate that both policy and market uncertainties can negatively affect corporate R & D investment. Policy uncertainty poses a significant impact on R & D investment for politically connected firms, but has no impact on firms without political connections. Market uncertainty only has a clear impact on non-politically connected firms. The negative influence of uncertainty is more obvious for firms receiving fewer government subsidies.Soft Science Project of Zhejiang Province [2014C35033]; Key Research Institute of Social Science and Humanities, The Ministry of Education [15JJD790031]; National Natural Science Foundation of China [71373011]SSCIARTICLE176-2004
