Investigating the Efficiency Coefficient of Pile Group in Clay Under Two-Way Lateral Load

This research investigates the behavior of a 2×2 pile group under two-directional lateral loads in addition to the vertical load.Through three-dimensional numerical modeling based on Flac 3D software,the study examines the total bearing capacity and efficiency coefficient of the pile group,considering factors such as the angle of lateral load,relative pile spacing,and relative stiffness of the pile-soil system.The findings highlight the significance of these factors in understanding and predicting the response of pile groups to changing lateral load directions.The results reveal that increasing the angle of the lateral load from 0°to 45°enhances both the maximum total lateral load and the efficiency coefficient of the pile group.When the relative stiffness of the pile-soil system significantly increases,soil stiffening occurs and reducing the relative spacing of the piles from 7 to 3 times the diameter of the piles diminishes the influence of the pile group.Consequently,the response of the pile group to lateral loads becomes more linear,with only a slight alteration in the maximum total lateral load and the efficiency coefficient when the lateral load is angled from 0°to 45°.Conversely,increasing the relative distance between the piles,specifically from 3 to 7 times the diameter of the piles,amplifies the influence of the pile group.Both the maximum total lateral load and the efficiency coefficient of the pile group exhibit an observed increase.These provide insights for designing pile groups and optimizing their performance under lateral loading conditions.

Secrecy Outage Probability for Two-Way Integrated Satellite Unmanned Aerial Vehicle Relay Networks with Hardware Impairments

In this paper,we investigate the secrecy outage performance for the two-way integrated satellite unmanned aerial vehicle relay networks with hardware impairments.Particularly,the closed-form expression for the secrecy outage probability is obtained.Moreover,to get more information on the secrecy outage probability in a high signalto-noise regime,the asymptotic analysis along with the secrecy diversity order and secrecy coding gain for the secrecy outage probability are also further obtained,which presents a fast method to evaluate the impact of system parameters and hardware impairments on the considered network.Finally,Monte Carlo simulation results are provided to show the efficiency of the theoretical analysis.

Two-way中继系统中的双向中继选择及功率分配策略

通过中继选择和功率分配,可以达到提高two-way中继系统总速率的目的。综合考虑中继节点处的接收信噪比和中继节点到目的节点间的信道增益,提出了two-way AF中继系统中的双向中继选择策略(BRS);同时,在总功率受限的条件下,建立了two-way AF中继系统中的优化功率分配模型,通过对模型进行数学分析求解,提出了一种自适应的最优功率分配策略(OPA)。仿真结果证明两种策略均能提高系统总速率。

Two-way中继系统中基于最小化中断概率的功率分配策略

为了降低Two-way中继系统中断概率,提出了一种Two-way中继系统中基于最小化中断概率的功率分配策略。首先推导了Two-way中继系统中断概率的闭合表达式,然后在总功率受限的条件下,提出了一种最小化中断概率的最优功率分配策略(OPA),通过拉格朗日乘数法对该优化模型进行了求解。仿真结果证明了该策略能够有效降低系统的中断概率,提高系统性能。

3D Two-way Coupled TEHD Analysis on the Lubricating Characteristics of Thrust Bearings in Pump-turbine Units by Combining CFD and FEA

The thermal elastic hydro dynamic （TEHD） lubrication analysis for the thrust bearing is usually conducted by combining Reynolds equation with finite element analysis （FEA）. But it is still a problem to conduct the computation by combining computational fluid dynamics （CFD） and FEA which can simulate the TEHD more accurately. In this paper, by using both direct and separate coupled solutions together, steady TEHD lubrication considering the viscosity-temperature effect for a bidirectional thrust bearing in a pump-turbine unit is simulated combining a 3D CFD model for the oil film with a 3D FEA model for the pad and mirror plate. Cyclic symmetry condition is used in the oil film flow as more reasonable boundary conditions which avoids the oil temperature assumption at the leading and trailing edge. Deformations of the pad and mirror plate are predicted and discussed as well as the distributions of oil film thickness, pressure, temperature. The predicted temperature shows good agreement with measurements, while the pressure shows a reasonable distribution comparing with previous studies. Further analysis of the three-coupled-field reveals the reason of the high pressure and high temperature generated in the film. Finally, the influence of rotational speed of the mirror plate on the lubrication characteristics is illustrated which shows the thrust load should be balanced against the oil film temperature and pressure in optimized designs. This research proposes a thrust bearing computation method by combining CFD and FEA which can do the TEHD analysis more accurately.

Buckling-controlled two-way shape memory effect in a ring-shaped bilayer

Shape memory polymers(SMPs)usually have a one-way shape memory effect.In this paper,an easy-operating method to realize a two-way shape memory effect was demonstrated in a ring-shaped bilayer structure where the two layers are SMPs with different thermal transition temperatures.By designing specific thermomechanical processes,the mismatched deformation between the two layers leads to a morphology change of ring-shaped bilayer structures from a smooth ring to a gear-like buckling shape under cooling and a reversible recovery to the smooth shape under heating.Such a morphology change is ascribed to occurrence and recovery of thermoelastic buckling.This method was validated by finite element simulation.We experimentally investigated the influence of pre-strain on buckling,and it was found that both the buckling occurrence and recovery temperature vary with pre-strain.Furthermore,considering a ring-shaped SMP-SMP bilayer structure,finite element analysis was conducted to study the influence of film thickness and modulus ratio of two layers on buckling behavior.The results showed that the critical buckling wavelength was greatly influenced by film thickness and modulus ratio.W e made a theoretical analysis that accorded well with the numerical results.

Experimental Study on a Single Layer Two-Way Grid Shell with Tension Members

Single layer two-way grid shell with in-plane and out-of-plane tension members is a new type of single-layer latticed shell roofs. Compared with traditional single-layer latticed shells,this new type has a unique mesh form and excellent rigidity. In order to further understand the buckling behaviors of single layer two-way grid cylindrical shell roof with tension members,the buckling experiments have been undertaken to investigate the effect of tension members,in either out-of-plane or in-plane placement. A single layer two-way grid cylindrical shell roof with out-of-plane tension members has been tested under symmetric and asymmetric loading. The tension member placement,the introducing initial axial force to tension members and the load patterns are considered to investigate the buckling behavior. Experimental results indicate that four long out-ofplane tension members work well under symmetrical loading,but only two long out-of-plane tension members work under asymmetrical loading. It can be concluded that the PC bar members used as tension members for this study are useful in the construction of a single layer two-way grid cylindrical shell roof with structural members intersecting at small angles.

Simulation and Analysis of China Climate Using Two-Way Interactive Atmosphere-Vegetation Model (RIEMS-AVIM)

In this paper, an Atmosphere-Vegetation Interaction Model （AVIM） is coupled to the Regional Integrated Environment Model System （RIEMS）, and a 10-year integration for China is performed using the RIEMS-AVIM. The analysis of the results of the 10-year integration shows that the characters of the spatial distributions of temperature and precipitation over China are well simulated. The patterns of simulated surface sensible and latent heat fluxes match well with the spatial climatological atlas： the values of winter surface sensible and latent heat fluxes are both lower than climatological values over the whole country. Summer surface sensible heat flux is higher than climatological values in western China and lower in eastern China, while summer surface latent heat flux is higher than climatological values in the eastern and lower in the western. Seasonal variations of simulated temperature and precipitation of RIMES-AVIM agree with those of the observed. Simulated temperature is lower than the observed in the Tibetan Plateau and Northwest China for the whole year, slightly lower in the remaining regions in winter, but consistent with the observed in summer. The simulated temperature of RIEMS-AVIM is higher in winter and lower in summer than that of RIEMS, which shows that the simulated temperature of RIEMS-AVIM is closer to the observed value. Simulated precipitation is excessive in the first half of the year, but consistent with the observed in the second half of the year. The simulated summer precipitation of RIEMS-AVIM has significant improvement compared to that of RIEMS, which is less and closer to the observed value. The interannual variations of temperature and precipitation are also fairly well simulated, with temperature simulation being superior to precipitation simulation. The interannual variation of simulated temperature is significantly correlated with the observed in Northeast China, the Transition Region, South China, and the Tibetan Plateau, but the correlation between precipitation simulation and observation is only significant in Northwest China.

Power Splitting Based SWIPT in Network-Coded Two-Way Networks with Data Rate Fairness:An Information-Theoretic Perspective

This paper investigates the simultaneous wireless information and powertransfer(SWIPT) for network-coded two-way relay network from an information-theoretic perspective, where two sources exchange information via an SWIPT-aware energy harvesting(EH) relay. We present a power splitting(PS)-based two-way relaying(PS-TWR) protocol by employing the PS receiver architecture. To explore the system sum rate limit with data rate fairness, an optimization problem under total power constraint is formulated. Then, some explicit solutions are derived for the problem. Numerical results show that due to the path loss effect on energy transfer, with the same total available power, PS-TWR losses some system performance compared with traditional non-EH two-way relaying, where at relatively low and relatively high signalto-noise ratio(SNR), the performance loss is relatively small. Another observation is that, in relatively high SNR regime, PS-TWR outperforms time switching-based two-way relaying(TS-TWR) while in relatively low SNR regime TS-TWR outperforms PS-TWR. It is also shown that with individual available power at the two sources, PS-TWR outperforms TS-TWR in both relatively low and high SNR regimes.

A Novel Forwarding Method for Full-Duplex Two-Way Relay Networks

An estimate-and-forward(EF) scheme for single-input single-output(SISO) and multiple-input multiple-output(MIMO) full-duplex two-way relay networks is proposed and analyzed. The relay estimates the received signal from two terminal nodes by a minimum mean squared error(MMSE) estimation and forwards a scaled version of the MMSE estimate to the destination. The proposed EF outperforms conventional amplify-and-forward(AF) and decode-and-forward(DF) across all signal-to-noise ratio(SNR) region. Because its computational complexity is high for relays with a large number of antennas(large MIMO) and/or high order constellations, an approximate EF scheme, called list EF, are thus proposed to reduce the computational complexity. The proposed list EF computes a candidate list for the MMSE estimate by using a sphere decoder, and it approaches the performance of the exact EF relay at a negligible performance loss. The proposed forwarding approach also could be used to other relay networks, such as half-duplex, one-way or massive MIMO relay networks.

Measurement-Device-Independent Quantum Key Distribution with Two-Way Local Operations and Classical Communications

Measurement-device-independent quantum key distribution （MDI-QKD） is proven to be immune to all the de- tector side channel attacks. With two symmetric quantum channels, the maximal transmission distance can be doubled when compared with the prepare-and-measure QKD. An interesting question is whether the transmission distance can be extended further. In this work, we consider the contributions of the two-way local operations and classical communications to the key generation rate and transmission distance of the MDI-QKD. Our numerical results show that the secure transmission distances are increased by about 12kin and 8 km when the 1 13 and the 2 B steps are implemented, respectively.

Security of the Decoy State Two-Way Quantum Key Distribution with Finite Resources

The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.

Two-way shape memory effect and alternating current driving characteristics of a TiNi alloy spring

Two-way shape memory effect (TWSME) was induced into the TiNi shape memoryalloys (SMAs) spring by thermomechanical training after annealing treatment, which has promisingapplication in micro-actuating fields. The TWSME spring can contract upon heating and extend uponcooling. The results show that there is an increase of the recovery ratio up to a maximum TWSME of45%. During the training procedure, transformation temperatures and hysteresis were measured bydifferent scanning calorimetry (DSC). The results show that A_s (reverse transformation starttemperature) and A_f (reverse transformation finish temperature) shift to lower temperature aftertraining. The intervals of A_fA_s and M_s-M_f (M_s and M_f are the martensite start and finishtemperatures, respectively) increase and the heat of transformation decreases after training. Theelectrothermal driving characteristics of the TWSME springs were also investigated with alternatingcurrent density of 3.2-14.7 A/mm^2. It is found that the time response and the maximum contractionratio greatly depend on the magnitude of the electrical current density.

Two-Way中继系统中基于最小化总功率的功率分配策略

在保证系统QoS前提下,为了降低Two-Way中继系统的总功率开销,提出了一种基于最小化总功率的优化功率分配策略。首先对Two-Way中继系统中断概率的闭合表达式进行了推导;在系统中断概率等于某一恒定值的条件下,建立了最小化系统总功率的优化模型。通过拉格朗日乘数法对优化模型进行了求解。仿真结果证明了此策略能降低系统总功率开销。

Effect of Training on Two-way Shape Memory Effect and Its Stability in a Ti-Ni-Hf High Temperature Shape Memory Alloy

The Effect of the thermal cycling training under constant strain on the two-way shape memory effect (TWSME) in a Ti36l\li49Hf15 high temperature shape memory alloy (SMA) has been investigated by bending tests. The results indicated that the training procedure is beneficial to get the better TWSME. The two-way shape memory strain increases with increasing the training strain. And it decreases with increasing the training temperature. The TWSME obtained in the present alloy shows poorer stability compared with that obtained in the TiNi alloys.

Joint power control and relay selection scheme for cognitive two-way relay networks

A joint power control and relay selection scheme is considered for a cooperative and cognitive radio system where a secondary network shares spectrum with the primary network. In the secondary network, two secondary users （SUs） communicate with each other via an assist relay. The main point is to provide the best system performance to SUs while maintaining the interference power at primary user （PU） under a certain level. Using convex optimization, a closed-form solution is obtained when optimizing the power allocation among the two nodes and relay. Based on this result, a joint power control and relay selection scheme with fewer variable dimensions is proposed to maximize the achievable rate of the secondary system. Simulation results demonstrate that the sum rate of the cognitive two-way relay network increases compared with a random relay selection and fixed power allocation.

Automatic Classification of Superimposed Modulations for 5G MIMO Two-Way Cognitive Relay Networks

To promote reliable and secure communications in the cognitive radio network,the automatic modulation classification algorithms have been mainly proposed to estimate a single modulation.In this paper,we address the classification of superimposed modulations dedicated to 5G multipleinput multiple-output(MIMO)two-way cognitive relay network in realistic channels modeled with Nakagami-m distribution.Our purpose consists of classifying pairs of users modulations from superimposed signals.To achieve this goal,we apply the higher-order statistics in conjunction with the Multi-BoostAB classifier.We use several efficiency metrics including the true positive(TP)rate,false positive(FP)rate,precision,recall,F-Measure and receiver operating characteristic(ROC)area in order to evaluate the performance of the proposed algorithm in terms of correct superimposed modulations classification.Computer simulations prove that our proposal allows obtaining a good probability of classification for ten superimposed modulations at a low signal-to-noise ratio,including the worst case(i.e.,m=0.5),where the fading distribution follows a one-sided Gaussian distribution.We also carry out a comparative study between our proposal usingMultiBoostAB classifier with the decision tree(J48)classifier.Simulation results show that the performance of MultiBoostAB on the superimposed modulations classifications outperforms the one of J48 classifier.In addition,we study the impact of the symbols number,path loss exponent and relay position on the performance of the proposed automatic classification superimposed modulations in terms of probability of correct classification.

Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis

A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the microstructure after training. the mechanism of TWSME in the Ti46.3 Ni44.7Nb9 alloy has been discussed.

The Average Achievable Rate of Multi-Antenna Two-Way Relay Networks with Interference Alignment

The large system analysis(LSA)has recently been shown to be a very useful tool for computing the average achievable rate.In this paper,we use LSA to derive the users’average achievable rate of multi-antenna two-way relay networks with interference alignment(IA),and we then derive the rate expressions under both equal power allocation and optimal power allocation.It is shown that the obtained closed-form rate expressions are functions of the average signal-to-noise ratio(SNR)for each data stream.Extensive simulation studies show that the average achievable rate expressions derived through LSA provide accurate estimates of the average achievable rate for two-way relay networks with interference alignment.

Quantum hacking of two-way continuous-variable quantum key distribution using Trojan-horse attack

We present a Trojan-horse attack on the practical two-way continuous-variable quantum key distribution system. Our attack mainly focuses on the imperfection of the practical system that the modulator has a redundancy of modulation pulsewidth, which leaves a loophole for the eavesdropper inserting a Trojan-horse pulse. Utilizing the unique characteristics of two-way continuous-variable quantum key distribution that Alice only takes modulation operation on the received mode without any measurement, this attack allows the eavesdropper to render all of the final keys shared between the legitimate parties insecure without being detected. After analyzing the feasibility of the attack, the corresponding countermeasures are put forward.