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51.
本文研究具有特殊亏量关系的亚纯函数与其k阶导数分担小函数集合的唯一性,改进,推广了李江涛,顾永兴,杨重骏,仪洪勋等人的有关结果. 相似文献
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Generalized processor sharing has been proposed as a policy for distributing processing in a fair manner between different
data classes in high-speed networks. In this paper we show how recent results on the Skorokhod Problem can be used to construct
and analyze the mapping that takes the input processes into the buffer content. More precisely, we show how to represent the
map in terms of a Skorokhod Problem, and from this infer that the mapping is well defined (existence and uniqueness) and well
behaved (Lipschitz continuity). As an elementary application we present some large deviation estimates for a many data source
model.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
54.
Jaume Martí-Farré 《Discrete Applied Mathematics》2006,154(3):552-563
The characterization of ideal access structures and the search for bounds on the optimal information rate are two important problems in secret sharing. These problems are studied in this paper for access structures with intersection number equal to one, that is, structures such that there is at most one participant in the intersection of any two different minimal qualified subsets. The main result in this work is the complete characterization of the ideal access structures with intersection number equal to one. In addition, bounds on the optimal information rate are provided for the non-ideal case. 相似文献
55.
Cheating in Visual Cryptography 总被引:3,自引:0,他引:3
A secret sharing scheme allows a secret to be shared among a set of participants, P, such that only authorized subsets of P can recover the secret, but any unauthorized subset cannot recover the secret. In 1995, Naor and Shamir proposed a variant
of secret sharing, called visual cryptography, where the shares given to participants are xeroxed onto transparencies. If
X is an authorized subset of P, then the participants in X can visually recover the secret image by stacking their transparencies together without performing any computation. In this
paper, we address the issue of cheating by dishonest participants, called cheaters, in visual cryptography. The experimental
results demonstrate that cheating is possible when the cheaters form a coalition in order to deceive honest participants.
We also propose two simple cheating prevention visual cryptographic schemes. 相似文献
56.
The coexistence of radar-sensing and communication systems research has received a surge of interest in recent times to tackle the issue of spectrum inadequacy. Designing an optimized radar waveform for a coexistence scenario has been a challenging task for accomplishing the convergence of radar-sensing and communication functionalities, without degrading the performance at either end. This paper proposes a novel global optimization-based Spatial Branch and Bound (SBnB) approach to optimize the phase coefficients of a Non-Linear Frequency Modulated (NLFM) waveform in a CRCS framework. In addition, the Modified-Power Ratio Constraint-Cramér–Rao Lower Bound (M-PRC-CRLB), a local optimization-based approach is proposed to optimize the phase coefficients of an NLFM waveform. The spectral energy distribution and auto-correlation characteristics of an NLFM waveform are comprehensively investigated for various values of polynomial order (N) and at different threshold Signal-to-Noise-Ratio (SNR) values. To compare the proposed waveform design approaches (M-PRC-CRLB, SBnB) with the existing waveform design approaches namely, Minimum Estimation Error Variance (MEEV) and PRC- CRLB, a Peak-to-Side-Lobe-Ratio (PSLR), and Integrated-Side-Lobe-Ratio (ISLR) are evaluated at various polynomial orders and threshold SNR values. Furthermore, the performance of a CRCS is assessed using the radar estimation rate and communication data rate. The simulation results reveal that the proposed optimized radar waveform design approaches provide improved performance compared to the existing radar waveform design approaches in terms of radar estimation rate. Further, the proposed global optimization-based SBnB approach achieves a comparable performance of the communication data rate. In addition, the proposed approaches accomplish enhanced spectral utilization, controlled side-lobe energy levels, reduced range-domain ambiguities, and a higher information rate in a CRCS. 相似文献
57.
In this paper, intelligent reflecting surface (IRS) technology is employed to enhance physical layer security (PLS) for spectrum sharing communication systems with orthogonal frequency division multiplexing (OFDM). Aiming to improve the secondary users’ secrecy rates, a design problem for jointly optimizing the transmission beamforming of secondary base station (SBS), the IRS’s reflecting coefficient and the channel allocation is formulated under the constraints of the requirements of minimum data rates of primary users and the interference between users. As the scenario is highly complex, it is quite challenging to address the non-convexity of the optimization problem. Thus, a deep reinforcement learning (DRL) based approach is taken into consideration. Specifically, we use dueling double deep Q networks (D3QN) and soft Actor–Critic (SAC) to solve the discrete and continuous action space optimization problems, respectively, taking full advantage of the maximum entropy RL algorithm to explore all possible optimal paths. Finally, simulation results show that our proposed approach has a great improvement in security transmission rate compared with the scheme without IRS and OFDM, and our proposed D3QN-SAC approach is more effective than other approaches in terms of maximum security transmission rate. 相似文献
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X射线光电子能谱仪的开放使用与管理 总被引:1,自引:1,他引:0
X射线光电子能谱仪(XPS)是材料表面元素定性和半定量分析的重要手段之一,是表面分析科研工作的必备仪器.为提高测试效率,实施了大型仪器设备开放共享优化,总结了在推动XPS开放过程中管理的经验和体会. 相似文献
60.
突发事件会增加供应链成本,如何进行成本分担是决定供应链能否协调应对突发事件的重要因素.用参数分别描述市场需求剧增时增加的生产成本和市场需求剧减时发生的多余产品处理成本,在数量折扣契约基础上,研究突发事件发生后制造商的最优批发价格和零售商的最优订货量,分析其影响因素比较突发事件发生前后包括市场剧增与市场剧减两种情况下的差异,并给出了数值算例.结果表明,成本分担系数和市场需求分布及其变化都会影响最优批发价格和最优订货量,只要根据市场需求变化相应调整契约参数并合理分担由突发事件增加的成本,通过数量折扣契约供应链就能够协调应对突发事件. 相似文献