Temporal rings with spiral ornamentation: the spreading area and chronology

The paper considers one of the categories of medieval jewelry – temporal rings with décor made of spirally twisted wire. The study characterizes finds from Eastern Europe known to date and provides data on jewelry from Central and South-Eastern Europe. The temporal rings of different design of their ends and spiral decorations are identified. Jewelry of this type is associated with the Byzantine jewelry tradition. The finds are concentrated in Slavic sites along the Danube, in Serbia, Bulgaria and Southeast Romania. They are not numerous in Central and Eastern Europe. Their chronology, as in the Danube-Balkan region, covers the 10th–14th centuries, the largest number of finds belonging to the second half of the 11th–13th century. Rings with a spiral decor could enter Northern Rus both as a result of trade and with settlers from the southern Rus lands. A small number of finds indicate that this type of jewelry did not become the subject of mass production outside the Danube-Balkan region.

Prediction and Suppression of Twisted-wire Pair Crosstalk Based on Beetle Swarm Optimization Algorithm

Based on the theory of multi-conductor transmission lines (MTL), this paper proposes a new method for predicting and suppressing crosstalk of twisted-wire pair (TWP). The per unit length (p.u.l) RLCG parameters change caused by the inconsistent cross-sectional shape of TWP, changes in parameters make it difficult to solve the telegraph equation. In this paper, the method of transmission lines cascade is used. TWP is divided into several segments, and p.u.l parameters of each segment are predicted. Compared with before method, we propose a higher precision algorithm—beetle swarm optimization (BSO) to optimize the weights of back-propagation (BP) neural network, which predict p.u.l parameters at each segment. On this basis, it is divided into two steps: 1) Use MTL frequency domain method combined with lines’ terminal conditions to solve crosstalk and compare with CST simulation results; 2) Use the singular value decomposition (SVD) method to add matrix modules at both ends of lines for suppressing crosstalk. The results show that proposed method in this paper is consistent with the simulation, and the accuracy is higher than before

Approach for CM/DM Current Extraction and Crosstalk Analysis of Twisted-Wire Pairs with Random Non-uniform Twisting

In this paper, a twisted-wire pairs (TWP) with random non-uniform twisting is established. It is divided into a complete pitch segment and a noncomplete pitch segment by the ratio between the pitch and the length. The randomness of the actual TWP cable is accurately simulated by the following methods: 1) random combination of complete pitch segments; 2) random combination of non-complete pitch segments; 3) random combination between 1) and 2). Based on the TWP model, an equivalent multi-conductor transmission lines (MTLs) model can be obtained. The neural network algorithm is introduced to describe the complex relationship between the arbitrary position of the TWP and the per-unit-length (p.u.l) parameter matrix. In addition, the crosstalk and the common-mode (CM) and differential-mode (DM) noise under field-to-wire coupling are predicted. The numerical results show that crosstalk and CM/DM noise in TWP cable are susceptible to the twisted pitch at high frequencies. Compared with full-wave simulation, the accuracy of the proposed method is proved.

Conceptualization and Prototype of an Anti-Erosion Sensing Revetment for Levee Monitoring: Experimental Tests and Numerical Modeling

The problem of levee embankment control during high flows is crucial for flood risk management in floodplains. Levee defense lines are often hundreds of kilometers long and surveys during emergencies are not easy tasks. For these reasons, levees monitored with in situ sensors and a suitable Information Technology (IT) real-time data communication and integration infrastructure, so-called “smart levees”, are gaining increasing interest as a crucial protection technology in floodplains. The paper presents the conceptualization of a prototype of a levee smart revetment, based on the integration of an optical fiber (OF) cable into a steel double-twisted wire mesh. In this paper the feasibility of this kind of revetment is firstly assessed. The flow pattern of overtopping water on the embankment is discussed, thus producing a raw estimation of the shear stress acting on the revetment in the field. A sample case is then analyzed in both numerical and laboratory tests. For this purpose, a numerical Finite Element Model (FEM) to describe the mechanical behavior of a double-twisted wire mesh when loaded along its own plane is presented. Numerical results indicate that the related strain, relatively low as compared to the steel wire yield stress, can be fully detected by the optical fiber continuous Brillouin sensor. This has been validated by the experimental activity performed and a digital twin of the prototype of the smart revetment, suitable for virtually testing the product under any load and constraint conditions and tailoring the production process, has been created.

Analysis of Crosstalk Problem in Multi-Twisted Bundle of Multi-Twisted Wire Based on BSAS-BP Neural Network Algorithm and Multilayer Transposition Method

Twisted wire used in complex systems has the ability to reduce electromagnetic interference, but crosstalk within the wire is not easy to obtain. This paper proposes a method to predict the crosstalk of multi-twisted bundle of multi-twisted wire (MTB-MTW). A neural network algorithm based on back propagation optimized by the beetle swarm antennae search method (BSAS-BPNN) is introduced to mathematically describe the relationship between the twist angle of the wire harness and the per-unit-length (p.u.l) parameter matrix. Considering the symmetry of the model, the relationship between the unresolved angle of the BSAS-BPNN algorithm and the p.u.l parameter matrix is processed by using the multilayer transposition method. Based on the idea of the cascade method and the finite-difference time-domain (FDTD) algorithm in Implicit-Wendroff format, the crosstalk of the wire is obtained. Numerical experiments and simulation results show that the new method proposed in this paper has better accuracy for the prediction of the model. The new method can be generalized to the MTB-MTW model with any number of wires. All theories provide preliminary theoretical basis for electromagnetic compatibility (EMC) design of high-band circuits.