Analysis on unit maximum capacity of orthogonal multiple watermarking for multimedia signals in B5G wireless communications

Beyond-5G(B5G)aims to meet the growing demands of mobile traffic and expand the communication space.Considering that intelligent applications to B5G wireless communications will involve security issues regarding user data and operational data,this paper analyzes the maximum capacity of the multi-watermarking method for multimedia signal hiding as a means of alleviating the information security problem of B5G.The multiwatermarking process employs spread transform dither modulation.During the watermarking procedure,Gram-Schmidt orthogonalization is used to obtain the multiple spreading vectors.Consequently,multiple watermarks can be simultaneously embedded into the same position of a multimedia signal.Moreover,the multiple watermarks can be extracted without affecting one another during the extraction process.We analyze the effect of the size of the spreading vector on the unit maximum capacity,and consequently derive the theoretical relationship between the size of the spreading vector and the unit maximum capacity.A number of experiments are conducted to determine the optimal parameter values for maximum robustness on the premise of high capacity and good imperceptibility.

Sealing capacity evaluation of underground gas storage under intricate geological conditions

Evaluating underground gas storage(UGS)sealing capacity is essential for its safe construction and operational efficiency.This involves evaluating both the static sealing capacity of traps during hydrocarbon accumulation and the dynamic sealing capacity of UGS under intensive gas injection and withdrawal,and alternating loads.This study detailed the methodology developed by Sinopec.The approach merges disciplines like geology,geomechanics,and hydrodynamics,employing both dynamic-static and qualitative-quantitative analyses.Sinopec's evaluation methods,grounded in the in situ stress analysis,include mechanistic studies,laboratory tests,geological surveys,stress analysis,and fluid-solid interactions.Through tests on the static and dynamic sealing capacity of UGS,alongside investigations into sealing mechanisms and the geological and geomechanical properties of cap rocks and faults,A geomechanics-rock damage-seepage mechanics dynamic coupling analysis method has been developed to predict in situ stress variations relative to pore pressure changes during UGS operations and evaluate fault sealing capacity and cap rock integrity,thereby setting the maximum operational pressures.Utilizing this evaluation technique,Sinopec has defined performance metrics and criteria for evaluating the sealing capacity of depleted gas reservoirs,enabling preliminary sealing capacity evaluations at UGS sites.These evaluations have significantly informed the design of UGS construction schemes and the evaluation of fault sealing capacity and cap rock integrity during UGS operations.

Flexible path planning-based reconfiguration strategy for maximum capacity utilization of battery pack

Maximizing the utilization of lithium-ion battery capacity is an important means to alleviate the range anxiety of electric vehicles.Battery pack inconsistency is the main limiting factor for improving battery pack capacity utilization,and poses major safety hazards to energy storage systems.To solve this problem,a maximum capacity utilization scheme based on a path planning algorithm is proposed.Specifically,the reconfigurable topology proposed is highly flexible and fault-tolerant,enabling battery pack consistency through alternating cell discharge and reducing the increased risk of short circuits due to relay error.The Dijkstra algorithm is used to find the optimal energy path,which can effectively remove faulty cells and find the current path with the best consistency of the battery pack and the lowest relay loss.Finally,the effectiveness of the scheme is verified by hardware-in-the-loop experiments,and the experimental results show that the state-of-charge SOC consistency of the battery pack at the end of discharge is increased by 34.18%,the relay energy loss is reduced by 0.16%,and the fault unit is effectively isolated.

Fixed Ammonium Content and Maximum Capacity of Ammonium Fixation in Major Types of Tillage Soils in Hunan Province,China

In order to understand the status of fixed ammonium, fixed ammonium content, maximum capacity of ammonium fixation, and their influencing factors in major types of tillage soils of Hunan Province, China, were studied with sampling on fields, and laboratory incubation and determination. The main results are summarized as follows： （1） Content of fixed ammonium in the tested soils varies greatly with soil use pattern and the nature of parent material. For the paddy soils, it ranges from 135.4 ± 57.4 to 412.8±32,4 mg kg^-1, with 304.7±96.7 mg kg^-1 in average; while it ranges from 59.4 to 435.7 mg kg^-1, with 230.1 ± 89.2 mg kg^-1 in average for the upland soils. The soils developed from limnic material and slate had higher fixed ammonium content than the soils developed from granite. The percentage of fixed ammonium to total N in the upland soils is always higher than that in the paddy soils. It ranges from 6.1 ±3.6% to 16.6±4.6%, with 14.0% ±5.1% in average for the paddy soils and it amounted to 5.8±2.0% to 40.1 ± 17.8%, with 23.5 ± 14.2% in average for upland soils. （2） The maximum capacity of ammonium fixation has the same trend with the fixed ammonium content in the tested soils. For all the tested soils, the percentage of recently fixed ammonium to maximum capacity of ammonium fixation is always bellow 20% and it may be due to the fact that the soils have high fertility and high saturation of ammonium-fixing site. （3） The clay content and clay composition in the tested soils are the two important factors influencing their fixed ammonium content and maximum capacity of ammonium fixation. The results showed that hydrous mica is the main 2：1 type clay mineral in 〈 0.02 mm clay of the paddy soils, and its content in 0.02-0.002 mm clay is much higher than that in 〈 0.002 mm clay of the soils. The statistical analysis showed that both the fixed ammonium content and the maximum capacity of ammonium fixation of the paddy soils were positively correlated with the total 2：1 type clay mineral content and hydrous mica content in 〈 0.02 mm clay and 0,02-0.002 mm clay at the significant level of P0.01 or P0.05, respectively, but not correlated with the total 2：1 type clay mineral content and hydrous mica content in 〈0.002 mm clay significantly, It demonstrated that the ammonium-fixing matrix of the tested soils mainly exists in the 0.02-0.002 mm clay. The above-mentioned results showed that fixed ammonium is a major form of N in the tillage soils in Hunan Province, China. It would play an important role in N nutrition of crops, especially for upland crops, and deserve to be further researched.

AN INVERSE MAXIMUM CAPACITY PATH PROBLEM WITH LOWER BOUND CONSTRAINTS

The computational complexity of inverse mimimum capacity path problem with lower bound on capacity of maximum capacity path is examined, and it is proved that solution of this problem is NP-complete. A strong polynomial algorithm for a local optimal solution is provided.

STUDY ON MAXIMUM HYDROGEN CAPACITY FOR Zr-Ni AMORPHOUS ALLOY

To design the amorphous hydrogen storage alloy efficiently, the maximum hydrogen capacities for Zr - Ni amorphous alloy were calculated. Based on the Rhomb Unit Structure Model(RUSM) for amorphous alloy and the experimental result that hydrogen atoms exist in 3Zr1Ni and 4Zr tetrahedron interstices in Zr-Ni amolphous alloy, the numbers of 3Zr-1Ni and 4Zr tetrahedron interstices in a RUSM were calculated which correspond to the hydrogen capacity. The two extremum Zr distribution states were calculated, such as highly heterogeneous Zr distribution and homogeneous Zr distribution. The calculated curves of hydrogen capacity with different Zr contents at two states indicate that the hydrogen capacity increases with increasing Zr content and reaches its maximum when Zr is 75%. The theoretical maximum hydrogen capacity for Zr - Ni amorphous alloy is 2.0 (H/M). Meanwhile, the hydrogen capacity of heterogenous Zr distribution alloy is higher than that of homogenous one at the same Zr content. The experimental results prove the calculated results reasonable, and accordingly, the experimental results that the distribution of Zr atom in amorphous alloy occur heterogeneous after a few hydrogen absorption desorption cycles can be explained.

The Clinical Role of Changes of Maximum Expiratory Flow at 25%and 50%of Vital Capacity before and after Bronchodilator Reversibility Test in Diagnosing Asthma

Summary:Changes of maximum expiratory flow at 25%and 50%of vital capacity(MEF2s and MEFso,respectively),and predominant parameters indicating small airways function in asthmatics before and after bronchodilator(BD)reversibility test have been less interpreted.Our study aimed to investigate the clinical role of changes of MEF2s and MEFso before and after BD reversibility test in diagnosing asthma.Forced expiratory volume in the first second(FEV),MEF2s,and MEFso were measured before and after BD reversibility test in 207 asthmatic patients using standard process.Forty healthy individuals were enrolled as controls.Receiver operating characteristic(ROC)curve was used to assess the diagnostic accuracy of reversibility of MEF2s and MEFgo before and after BD reversibility test(OMEF 2s%and AMEF so%,respectively)in diagnosing asthma.Among these functional criteria,AMEF2;%and 0MEFs%≥25%performed the best diagnostic performance.The sensitivity,specificity,and accuracy of AMEF 25%≥25%as an objcctive diagnostic test for asthma were 63.29%,87.50%,and 67.21%,and of AMEFs0%≥25%were 79.23%,85.00%,and 80.16%,respectively.The area under the ROC curve of the indicators was 0.8203 and 0.9104,respectively.By contrast,an increase in FEV≥12%and 200 mL demonstrated a sensitivity of 62.32%,specificity of 82.50%,and accuracy of 65.59%in diagnosing asthma.The changes of MEF2s and MEFso before and after BD reversibility test may be of additional value in the clinical diagnosis of asthma,with cutoff values of 25%being the most.

Increasing the Maximum Capacity Path in a Network and Its Application for Improving the Connection Between Two Routers

Abstract:This paper addresses the problem of improving the optimal value of the Maximum Capacity Path(MCP)through expansion in a flexible network,and minimizing the involved costs.The only condition applied to the cost functions is to be non-decreasing monotone.This is a non-restrictive condition,reflecting the reality in practice,and is considered for the first time in the literature.Moreover,the total cost of expansion is a combination of max-type cost(e.g.,for supervision)and sum-type cost(e.g.for building infrastructures,price of materials,price of labor,etc.).For this purpose,two types of strategies are combined:(l)increasing the capacity of the existing arcs,and(l)adding potential new arcs.Two different problems are introduced and solved.Both the problems have immediate applications in Internet routing infrastructure.The first one is to extend the network,so that the capacity of an McP in the modified network becomes equal to a prescribed value,therefore the cost of modifications is minimized.A strongly polynomial-time algorithm is deduced to solve this problem.The second problem is a network expansion under a budget constraint,so that the capacity of an McP is maximized.A weakly polynomial-time algorithm is presented to deal with it.In the special case when all the costs are linear,a Meggido's parametric search technique is used to develop an algorithm for solving the problem in strongly polynomial time.This new approach has a time complexity of O(n^(4)),which is better than the time complexity of O(n4 log(n)of the previously known method from literature.

ON THE BOTTLENECK CAPACITY EXPANSION PROBLEMS ON NETWORKS

This article considers a class of bottleneck capacity expansion problems. Such problems aim to enhance bottleneck capacity to a certain level with minimum cost. Given a network G（V,A,C^-） consisting of a set of nodes V = {v1,v2,... ,vn}, a set of arcs A C {（vi,vj） ｜ i = 1,2,...,n; j = 1,2,...,n} and a capacity vector C. The component C^-ij of C is the capacity of arc （vi, vj）. Define the capacity of a subset A′ of A as the minimum capacity of the arcs in A, the capacity of a family F of subsets of A is the maximum capacity of its members. There are two types of expanding models. In the arc-expanding model, the unit cost to increase the capacity of arc （vi, vj） is ωij. In the node-expanding model, it is assumed that the capacities of all arcs （vi, vj） which start at the same node vi should be increased by the same amount and that the unit cost to make such expansion is wi. This article considers three kinds of bottleneck capacity expansion problems （path, spanning arborescence and maximum flow） in both expanding models. For each kind of expansion problems, this article discusses the characteristics of the problems and presents several results on the complexity of the problems.

Determining capacity of multimodal multi-commodities freight transportation network from critical link volumes

The commodity transportation capacity between all origin-destination （ OD ） pairs over the multimodal multi-commodities freight transportation network （MMFTN） is determined. A multi-ob- jectives mathematical model is formulated for determining the OD capacity over the MMFTN accord- ing to a transporting capacity matrix that increased from the reference matrixes. The corresponding incremental factor for estimating the capacity matrix is obtained via the maximal likelihood estima- tion method that samples data of differences between the estimated commodity volumes and carrying capacities of the critical links. The proposed formulations are tested by an experimental highway and railroad freight transportation network in an existing literature. The relevant results of OD capacities are displayed and applicability of the algorithm is certified.

Capacity and outage probability analysis of downlink MRT-SC in distributed antenna system

This paper investigates the downlink capacity distribution and the outage probability of the interested area of maximum ratio transmission-selection combining(MRT-SC) scheme in the distributed antenna system(DAS).Composite fading channels are assumed,which include path loss,lognormal shadowing and multi-path Rayleigh fading.Analytical approximations of the capacity's cumulative distribution function(CDF),the outage capacity,the mean capacity,and the outage probability of the interested area are derived by means of moment generation function(MGF) and Gauss-Hermite series expansion based approaches.The influence of antenna number,path loss exponent,and shadowing standard deviation on the capacity distribution are investigated.The simulation results agree with the analytical approximations well,and thus the analytical approximations are able to substitute the time-intensive Monte Carlo simulation for further investigation.

Adjustment of Liquid Production in Reservoir with Handling Capacity Constraints

A oilfield was an oil reservoir with strong bottom water in offshore, the water cut was as high as 96%. In the high water cut stage, the most effective way of increasing oil production was to extract liquid and increase oil. The processing capacity of oilfield fluid was limited by the conditions. By using Petrel-RE-2017 software, combining reservoir engineering and percolation mechanics methods, this paper analyzes the effect of large-scale liquid pumping, expand coverage and shut-in coning in oil reservoirs with bottom water, and formulates the adjustment strategy of single well production structure of the whole oilfield. It was confirmed that large-scale liquid production can expand coverage and shutting down well can reduce water cut. It can provide reference and guidance for oil field with strong bottom water when it encounters bottleneck of liquid treatment capacity.

Minimum Cost of Capacity Expansion for Time-Limited Transportation Problem On-Demand

The minimum cost of capacity expansion for time-limited transportation problem on-demand (MCCETLTPD) is to find such a practicable capacity expansion transportation scheme satisfying the time-limited T along with all origins’ supply and all destinations’ demands as well as the expanding cost is minimum. Actually, MCCETLTPD is a balance transportation problem and a variant problem of minimum cost maximum flow problem. In this paper, by creating a mathematical model and constructing a network with lower and upper arc capacities, MCCETLTPD is transformed into searching feasible flow in the constructed network, and consequently, an algorithm MCCETLTPD-A is developed as MCCETLTPD’s solution method basing minimum cost maximum flow algorithm. Computational study validates that the MCCETLTPD-A algorithm is an efficient approach to solving the MCCETLTPD.

小麦叶片和冠层尺度气体交换模型关键参数的季节变化特征

本文从叶片和冠层尺度入手,采用手持式光合仪和涡动相关法,分析确定C3作物春小麦和冬小麦气体交换模型关键参数随季节变化的特征。结果表明:春小麦叶片尺度最大羧化速率和最大电子传递速率在生育末期快速减小,其他阶段差异不显著,但二者之比随发育期变化相对稳定,均值为2.2;春小麦生长季叶片气孔导度模型斜率在9~11间变动,均值为9.7。冬小麦冠层尺度最大羧化速率和最大电子传递速率随发育期呈抛物线变化,但二者之比相对稳定,均值为1.43;冬小麦冠层导度模型斜率在不同年份不同季节变化无明显规律,整个生育期围绕均值12波动。本研究论证了表征作物光合能力的参数随生育期变化以及气孔导度模型斜率相对稳定的特征。可为陆气相互作用过程分析以及生态系统碳—水循环模拟提供参数化依据。

汶川震区山洪灾害场次洪水最大携沙量预测模型

汶川地震后,震区产生了大量松散堆积体,受强降水影响产生了破坏性更强的山洪灾害,加剧了灾害的危险性,增加了灾害防治的困难度,研究震区山洪灾害可为评估灾害的风险性及后续的管理提供依据。本研究以66处历史山洪灾害作为样本数据,进行可量算影响因子的相关性分析,揭示山洪灾害的携沙量影响机制,确定流域面积、主沟长度、相对高差、物源量四个影响因子作为主控因子,基于SPSS进行非线性回归分析,建立了基于场次洪水最大携沙量及最大携沙距离的估算模型,并选取了汶川县和都江堰市的共23处山洪水沙灾害数据进行了模型的验证且与其他模型对比。结果表明,本研究建立的模型可靠性好,精度更高。研究成果有助于预测汶川震区潜在的山洪水沙灾害区域,为山洪水沙灾害的风险评估提供依据。

语义通信的数学理论

自从1948年经典信息论诞生以来,在其指导下,现代通信技术已经逼近了理论性能极限,例如信息熵H(U)、信道容量C=max_(p(x))I(X;Y)以及率失真函数R(D)=min_(p(x|x):Ed(x,x)≤D)I(X;X)。长期以来,由于经典信息论只研究语法信息,限制了通信科学的进一步发展。近年来,研究语义信息处理与传输的通信技术获得了学术界的普遍关注,语义通信开辟了未来通信技术发展的新方向,但还缺乏一般性的数学指导理论。为了解决这一难题,构建了语义信息论的理论框架,对语义信息的度量体系与语义通信的理论极限进行了系统性阐述。首先,通过深入分析各类信源的数据特征,以及各种下游任务的需求,总结归纳出语义信息的普遍属性——同义性。由此指出语义信息是语法信息的上级概念,是许多等效或相似语法信息的抽象特征,表征隐藏在数据或消息背后的含义或内容。将语义信息与语法信息之间的关系命名为同义映射,这是一种“一对多”映射,即一个语义符号可以由许多不同的语法符号表示。基于同义映射f这一核心概念,引入语义熵H_(s)(U)作为语义信息的基本度量指标,表示为信源概率分布与同义映射的泛函。在此基础上,引入上/下语义互信息I^(s)(X;Y)(I_(s)(X;Y)),语义信道容量C_(s)=max_(f_(xy))max_(p_((x)))I^(s)(X;Y)以及语义率失真函数R_(s)(D)=min_({f_(x),f_(x)})min_(p(x|x):Ed_(s)(x,x)≤D)I_(s)(X;X),从而构建了完整的语义信息度量体系。这些语义信息度量是经典信息度量的自然延伸,都由同义映射约束,如果采用“一对一”映射,则可以退化为传统的信息度量。由此可见,语义信息度量体系包含语法信息度量,前者与后者具有兼容性。其次,证明了3个重要的语义编码定理,以揭示语义通信的性能优势。基于同义映射,引入新的数学工具——语义渐近均分(AEP),详细探讨了同义典型序列的数学性质,并应用随机编码和同义典型序列译码/编码,证明了语义无失真信源编码定理、语义信道编码定理和语义限失真信源编码定理。类似于经典信息论,这些基本编码定理也都是存在性定理,但它们指出了语义通信系统的性能极限,在语义信息论中起着关键作用。由同义映射和这些基本编码定理可以推断,语义通信系统的性能优于经典通信系统,即语义熵小于信息熵H_(s)(U)≤H(U),语义信道容量大于经典信道容量C_(s)≥C,以及语义率失真函数小于经典率失真函数R_(s)(D)≤R(D)。最后,讨论了连续条件下的语义信息度量。此时,同义映射转换为连续随机变量分布区间的划分方式。相应地,划分后的子区间被命名为同义区间,其平均长度定义为同义长度S。特别是对于限带高斯信道,得到了一个新的信道容量公式C_(s)=B log[S^(4)(1+P/N_(0)B)],其中,平均同义长度S表征了信息的辨识能力。这一容量公式是经典信道容量的重要扩展,当S=1时,该公式退化为著名的香农信道容量公式。综上所述,语义信息论依据同义映射这一语义信息的本质特征,构建了语义信息的度量体系,引入新的数学工具,证明了语义编码的基本定理,论证了语义通信系统的性能极限,揭示了未来语义通信的巨大性能潜力。

煤层亚临界/超临界CO_(2)吸附特征与封存模式

大规模高效CO_(2)地质封存是短期内快速实现CO_(2)减排的关键途径之一,以吸附特征为主要封存机制的深部不可采煤层CO_(2)封存具有规模化实施的潜力。为研究深部煤层CO_(2)封存机制,以沁水盆地无烟煤为研究对象,开展了高温高压CO_(2)吸附实验,并采用简化局部密度模型(SLD-PR)拟合,分析了温压变化下不同孔隙的吸附相密度分布特征,揭示了以吸附相密度和最大吸附层厚度协同变化为核心的煤层CO_(2)封存机理,最后通过准确划分孔内吸附空间与自由空间,预测了不同埋深下煤层CO_(2)封存量。研究结果表明:(1)不同温度下超临界CO_(2)吸附曲线均表现出典型的超临界气体吸附特征,过剩吸附量(最大值介于1·25~1·75 mmol/g)在达到最大值后下降;(2)孔隙内CO_(2)吸附层分为接触层、内层和过渡层,亚临界CO_(2)在孔内以单分子层吸附为主,而超临界CO_(2)吸附方式为多分子层吸附;(3)最大吸附层厚度随埋深增加而减小,与温度呈正相关,而与压力呈负相关;(4)CO_(2)平均吸附相密度随埋深“先增后减”,总封存量与绝对吸附量曲线在CO_(2)处于超临界状态下存在差异。结论认为:(1)在吸附空间与吸附相密度协变下,煤层CO_(2)微观封存模式随埋深可分为亚临界单分子层吸附、超临界类气态多分子层吸附型以及超临界类液态多分子层吸附3种类型,自由相封存量对总封存量的贡献随埋深增加,但吸附封存仍是煤层CO_(2)封存的主要方式;(2)研究成果揭示了原位煤层超临界CO_(2)封存机理,能够为深部煤层CO_(2)封存能力评价提供新认识。

气顶砂岩油藏型储气库运行上限压力和库容量定量评价研究

提高运行上限压力是增加储气库工作气量最直接、最有效且综合效益最优的方案。通过在矿场井中原位实测得到的最小主应力,对冀东南堡油田1-29气顶砂岩油藏型储气库的运行上限压力和库容量进行了定量评价,研究结果表明:基于最小主应力准则,盖层发生拉张破坏对应的上限压力最低,即根据实测最小主应力确定南堡油田1-29储气库的运行上限压力为27.2 MPa。基于有效库容计算模型,综合考虑气层含水量、残余水和边缘孔隙以及油层的波及系数、气驱液效率和含油空间利用率等因素,将上限压力从原始地层压力22.5 MPa提升到27.2 MPa,储气库的有效库容从15.46×10^(8)m^(3)增加到18.14×10^(8)m^(3),库容量增加约17.3%,预期可显著提升储气库的经济效益。研究成果对其他地下储气库运行上限压力和库容量定量评价具有一定参考价值。

有向网络中最大容量支撑树形图扩容问题

针对有向网络中最大容量支撑树形图扩容问题(EMCSA),由0-1背包问题出发归约出EMCSA问题的一个实例,从而证明EMCSA问题是NP-困难的,并且给出解决EMCSA问题的一个启发式算法。最后,考虑EMCSA问题的一种特殊情况:有向网络中最大容量支撑树形图的最少弧扩容问题(NEMCSA),采用权重差最小换弧方法设计时间复杂度为O(mn)的多项式时间算法。

多直流馈入受端电网的最大受电能力估计方法

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