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Incident power has an important effect on the optical transmission properties of magnetic fluids. Difference in the effect of the incident power on the optical transmission properties with and without an applied magnetic field was investigated by measuring the transmitted power of the incident light through the magnetic fluid film. In the absence of an applied magnetic field, an approximately linear relationship exists between the incident power and the transmitted power of magnetic fluid films, but the relationship is nonlinear when a magnetic field is applied. Moreover, variation in the optical transmission properties under a magnetic field with various incident powers was measured in experiment. As the magnetic field is enhanced, the transmitted power of the magnetic fluid film first decreases, then increases, and finally reaches saturation. The magnitude of the change in the transmitted power, and the magnetic field range correspond to decreases, increases and saturation are related to the incident power. Therefore, for the sensing applications, depending on the measuring range of the magnetic field and the required variation range of the transmitted power, magnetic fluid film sensors exhibit different characteristics if different incident power values are selected.

In this paper, the wave propagation method and the differential constitutive law consequent (not equivalent) to the Eringen strain-driven integral nonlocal elasticity model are utilized to analyze the free vibration, wave power transmission and reflection in multi-cracked nanorods. This aim is pursued by deriving the propagation, reflection and transmission matrices and comparing the natural frequencies obtained by these matrices with the available results in the literature. Then, the nonlocal, crack-severity, and crack location effects on the natural frequencies are presented for two combinations of the boundary conditions. Finally, the paper presents the effects that the reflected and transmitted power of a wave incident on a crack location receive from the nonlocal and crack-severity parameters. The results obtained via the reflection and transmission matrices will provide valuable insights into the subject of wave power reflection and transmission analysis in nanoscale structures for the future. The computer coding of the proposed method is much easier than the classical vibration analysis methods which makes it more appropriate in implementation.

In this paper, the wave propagation method and the nonlocal elasticity theory are utilized to analyze the vibration, wave power transmission and reflection in multi-cracked Euler-Bernoulli nanobeams. This aim is pursued by deriving the propagation, reflection and transmission matrices and comparing the natural frequencies obtained by these matrices with the available results in the literature. Then, the nonlocal and crack-severity effects on the natural frequencies are presented for some combinations of the boundary conditions. Finally, the effects of nonlocal and crack-severity parameters on the reflected and transmitted power of a wave incident upon a crack location are studied in details for cracked nanobeams. The results obtained via the reflection and transmission matrices will provide valuable insights into the subject of wave power reflection and transmission analysis in nanoscale structures for the future. The computer coding of the proposed method is much easier than the classical vibration analysis methods for similar analyses which makes it more appropriate in implementation.

A new formula for the signal-to-four-wave mixing (FWM) crosstalk in 2-D time-spreading wavelength-hopping (TW) optical code division multiple access (OCDMA) systems is derived. The influence of several system parameters on the signal-to-FWM crosstalk ratio (SXR) is analyzed, including transmitted power per chip, code length, the number of active users, code weight, wavelength spacing, and transmission distance. Furthermore, for the first time, a closed-form expression for the total number of possible FWM products employing symmetric TW codes with equal wavelength spacing is investigated. The results show that SXR is sensitive to minor variations in system parameters, especially the launched power level and the code length while the wavelength spacing has a less impact on the level of the generated FWM power.

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ Today's optical transport networks are complex already and the support of the new arising services will further increase such complexity. Traditional deterministic network procedures will need to be revisited, especially their operations. Network Operators will require more dynamic approaches to get the best out of their infrastructure. In this context, cognition and machine learning techniques can provide innovative management solutions for traditional telecom operators. In this paper, we explore a dynamic cognitive approach to improve the adaption of Network Operators' operational processes to the new digital age. We propose a dynamic strategy considering the Case-Base Reasoning (CBR) technique for helping to reduce overall costs by optimizing operation margins. In this way, highly competitive exploitation methods to support new services can be deployed. The proposed dynamic algorithms can achieve higher transmitted power efficiency, up to 20% versus previously proposed static solutions, prolonging the transceivers' lifetime and thus addressing telco operator costs reduction. This work has been supported by the Spanish Government through project ALLIANCE (TEC2017-90034-C2-2-R) with FEDER contribution.

Two miter bends are described for monitoring the power transmitted in an oversized corrugated wave-guide. One has an array of holes in its mirror that couples a small fraction of the incident power to a rectangular waveguide directly machined into the mirror. Millimeter-wave detectors on the outputs of this miter bend can respond very rapidly to the transmitted power, but the coupling is sensitive to the mode purity in the oversized waveguide. The other miter bend monitors the power by measuring the rise in temperature of the cooling water passing through the mirror. The mirror is well isolated from the miter bend housing to prevent heat from neighboring waveguides from reaching the mirror. The measurement requires about 200 s to reach steady state, but it is relatively insensitive to mode purity. The measurement does require knowledge of the input polarization. Thermo-mechanical analyses of the miter bends indicate that they are capable of reliable operation with 1.5 MW transmitted through them. High-power long-pulse 170 GHz tests of these miter bends at the Japan Atomic Energy Agency (JAEA) are described.

A technique for Peak-to-Average Power Ratio (PAPR) reduction of Orthogonal Frequency Division Multiplexing (OFDM) signals by Peak Insertion (PI) is proposed in this paper. PI depends on the duality property of the DFT and PAPR duality of an impulse. A relatively high peak is inserted to the OFDM symbol in the frequency domain such that the PAPR of the transmitted time domain signal is reduced. PAPR reduction up to about 11 dB at PAPR CCDF of 10 −4 is achievable by PI, but at the expense of increased signal power, which can be reduced by scaling to the desired level without affecting its PAPR. Computer simulation tests show that a tradeoff can easily be made between BER and the PAPR of the transmitted signal to achieve a desired system performance. The PI technique does not require any sort of side information transmission, searching, optimization, and iterative or parallel application of IDFT. PI is faster, simpler, and capable of achieving greater PAPR reduction as compared with other similar techniques which result in transmitted power increase, and therefore, it seems to be suitable to be used for OFDM signal PAPR reduction.

The work in this paper a simulation of two-dimension (2-D) modified double weight (MDW) optical code division multiple access (OCDMA) wavelength-time and 2-D difference perfect code PDC, focusing on a comparison between the two codes with 1 k =4 (the code weight of spectra code sequence), 2 k =2 (the code weight of time-chip) for 2-D MDW code and 1 k =3, 2 k =2 for 2-D PDC with four users. The simulation is done with Optisystem program V11, can notice that 2-D MDW code indicates substantial performance improvements in bit error rate (BER), data rate and distance and achieves good performance; below 10-9 BER error floor for lowest effective transmitted power (P sr ) reached -20 dB and successfully suppresses PIIIN and mitigating MAI compared with PDC.

A miniaturized optical fiber probe for measuring esophageal pressure, that makes use of biconically-tapered fibers, has been built and characterized. The functioning of this probe is based on the decrease in transmitted power in the fiber, when it is bent in its biconical part under the action of pressure. We made and tested several probes, using different fibers (monomode and few-modes) and different tapering values. Our best result was achieved with a probe which utilizes a biconical monomode fiber that has a waist diameter of 36 μm. The resolution obtained was 2 mm Hg in the range between 5 and 55 mm Hg.

A system is described and analysed which applies random signal correlation techniques to ultrasonic flaw detection. The use of correlation and time integration techniques gives it a signal-to-noise ratio correlation gain of the order of 10 4 , and the use of a random transmitted signal whose range resolution is independent of its duration permits a peak-to-average transmitted power ratio of the order of unity. It is shown that random signal correlation systems should therefore be capable of much greater range and/or resolution than is possible with current pulse-echo systems.

The mechanism of a group of multiple-stage, variable-speed transmission is examined. These transmissions allow a change of speed stage to occur without a drop in transmitted power and without a change in setting of the variable-ratio unit. The kinematic restrictions imposed on the mechanism by synchronous coupling of the speed stages are outlined for all possible sequences of speed stages.