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The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation of and present a kind of sensing system for monitoring simultaneous temperature and strain measurements based on highly nonlinear fiber (HNLF) and single mode fiber (SMF).

First, the stimulated Brillouin scattering (SBS) characteristics of the HNLF have been studied, including the Brillouin gain bandwidth, Brillouin gain center frequency and SBS threshold. Second, based on the Brillouin gain center frequency, the Brillouin frequency shift coefficients of strain and temperature in HNLF have been studied. Third, the sensing and signal interrogation scheme for simultaneous monitoring of temperature and strain with high resolution has been presented.

It is found that the HNLF has a wider Brillouin gain bandwidth. The SBS threshold of HNLF is 78 mW, which is much larger than 7.9 mW of SMF. Also, the Brillouin frequency shift coefficients of strain and temperature in HNLF are 0.0308 and 0.413 MHz/°C, respectively.

The larger threshold of SBS is useful to avoid SBS under certain situations that Spontaneous Brillouin Scattering is necessary and should be applied. The technique is based on the fact that the Brillouin frequency shift coefficients of strain and temperature in HNLF are different from those in SMF. Therefore, the two-parameter monitoring can be achieved by producing SBS and obtaining the back-scattering Brillouin signal light simultaneously in HNLF and SMF.

This paper aims to propose and demonstrate a novel surface plasmon resonance (SPR)-sensing approach by using the fundamental mode beam based on a graded index multimode fiber (GIF). The proposed SPR sensor has high sensitivity and controllable working dynamic range, which expects to solve the two bottlenecks of fiber SPR sensor, including low sensitivity and the difficulty in multichannel detection.

The low-order mode of the GIF to SPR sense, which keeps the sensitivity advantage of the single-mode fiber SPR sensor, is used. By using this new SPR sensor, the effect of light incident angle and gold film thickness on working dynamic range was studied. According to the study results, the smaller is the incident angle, the larger is the SPR working dynamic range and the longer is the resonance wavelength with a fixed gold film thickness; the larger is the gold film thickness, the longer is the resonance wavelength with a fixed grinding angle. After the parameter optimization, the sensitivity of these two parameter-adjusting methods reach 4,442 and 3031 nm/RIU.

When the grinding angle of the GIF increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed gold film thickness. Similarly, when gold film thickness increases, the dynamic range of the resonance wavelength increases and has a redshift, sensitivity increases, and the resonance valley becomes more unobvious with a fixed grinding angle. These adjusting performance aforementioned lay the foundation for solving of the fiber-based SPR multichannel detection and increasing of the fiber-based SPR sensor sensitivity, which has a good application value.

The purpose of this paper is to present a dual-mode proximity sensor composed of inductive and capacitive sensing modes, which can help the robot distinguish different objects and obtain distance information at the same time. A systematic study of sensor response to various objects and the function of cooperation sensing is needed. Furthermore, the application in the field of robotic area needs to be discussed.

Numerical modeling of each sensing modes and simulations based on finite element analysis method has been carried out to verify the designed dual-mode sensor. A number of objects composed of different materials are used to research the cooperation perception and proximity sensing functions. In addition, the proposed sensor is used on the palm of a mechanical hand as application experiment.

The characteristics of the sensor are summarized as follows: the sensing range of inductive mode is 0-5.6 mm for detecting a copper block and the perceive range of capacitive mode is 0-5.1 mm for detecting a plastic block. The collaborative perceive tests validated that the non-ferromagnetism metals can be distinguished by inductive mode. Correspondingly, ferromagnetism metals and dielectric objects are differentiated by capacitive mode. Application experiments results reveal that both plastic bottle and steel bottle could be detected and differentiated. The experimental results are in agreement with those of simulations.

This paper provides a study of dual-mode proximity sensor in terms of design, experiments and application.

The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.

The sensor array consists of a sandwich structure. Sensing elements are distributed discretely in the sensor. Each sensing element has two electrodes and a piece of conductive rubber with piezoresistive property. The electrodes, as well as the conductive trace for signal transmission, are printed on the substrate layer by the screen printing technique. A scanning circuit based on zero potential method and an experimental set‐up based on balance to characterize the sensor array are designed and implemented in the test of the sensor array.

Experimental results verify the validity of the sensor array in measuring the vertical tactile force between the sensing elements and the object.

In this paper, all the sensors are tested without calibration procedures and the procedure of the dynamic test is implemented by manual operation.

The sensor array could be applied to measure the plantar force for gait detection in clinical applications.

The paper presents a tactile force sensor array with discrete sensing elements to essentially restrict the cross‐talk among sensing elements. This paper will provide many practical details that can help others in the field.

Dynamic capabilities (DCs) upgrade operational capabilities. However, DC dimensions of sensing, seizing and reconfiguring may combine in different configurations that result in alternative outcomes, depending on the firm's lifecycle stage. The purpose of this research is to explore configurations of DC dimensions during different stages of firms' lifecycles that result in operational marketing and technological capabilities.

Given the limited understanding of how DC dimensions and operational capabilities interact across a firm's lifecycle, the authors employed a multi-method approach to understand whether different configurations of DC dimensions may lead to operational marketing and technological capabilities and how the firm's lifecycle may condition these configurations. The authors first apply PLS path modelling to assess the validity and reliability of the measures. Then, the authors use fuzzy-set qualitative comparative analysis (fsQCA) to analyse micro, small and medium-sized enterprises (SMEs) in different growth stages operating in the creative industry within highly competitive and fast-changing environments.

Results show that several configurations of DC dimensions and competitive intensity influence marketing and technological capabilities. Although several configurations include sensing, seizing and reconfiguring, the findings also point to configurations where not all DC dimensions are present.

Improving operational capabilities does not necessarily imply a simultaneous presence of all three DC dimensions. Especially in the growth stage, managers that face resources shortage may only focus on sensing and seizing dimensions when developing marketing capabilities.

This research focuses on configurations of DC dimensions (instead of configurations of different types of DCs) that generate diverse marketing and technological capabilities development paths. The authors provide several equifinal configurations of DC dimensions that lead to operational marketing and technological capabilities. This study contributes to disentangling DCs and their dimensions across different lifecycle stages.

Cognitive radio (CR) plays a very important role in enabling spectral efficiency in wireless communication networks, where the secondary user (SU) allows the licensed primary users (PUs). The purpose of this paper is to develop a prediction model for spectrum sensing in CR.

This paper proposes a hybrid prediction model, called krill-herd whale optimization-based actor critic neural network and hidden Markov model (KHWO-ACNN-HMM). The spectral bands are determined optimally using the proposed hybrid prediction model for allocating the spectrum bands to the PUs. For better sensing, the eigenvalue based on cooperative sensing used in CR. Finally, a hybrid model is designed by hybridizing KHWO-ACNN and HMM to enhance the accuracy of sensing. The predicted results of KHWO-ACNN and HMM are combined by a fusion model, for which a weighted entropy fusion is employed to determine the free spectrum available in CRs.

The performance of the prediction model is evaluated based on metrics, such as probability of detection, probability of false alarm, throughput and sensing time. The proposed spectrum sensing method achieves maximum probability of detection of 0.9696, minimum probability of false alarm rate as 0.78, minimum throughput of 0.0303 and the maximum sensing time of 650.08 s.

The proposed method is useful in various applications, including authentication applications, wireless medical networks and so on.

A hybrid prediction model is introduced for energy efficient spectrum sensing in CR and the performance of the proposed model is evaluated with the existing models. The proposed hybrid model outperformed the other techniques.

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the measurement dimension and the principle of the sensing configuration. Some commercial sensors have also been introduced and future work in this field has also been discussed. This paper could provide an important reference for the research community.

This review is to present the state of the art for FBG acceleration sensing technologies from two aspects: the principle of the measurement dimension (one-dimension and multi-dimension) and the principle of the sensing configuration (beam type, radial vibration type, axial vibration type and other composite structures).

The current research on developing FBG acceleration sensors is mainly focused on the sensing method, the construction and design of the elastic structure and the design of a new information detection method. This paper hypothesizes that in the future, the following research trends will be strengthened: common single-mode fiber grating of the low cost and high utilization rate; high sensitivity and strength special fiber grating; multi-core fiber grating for measuring single-parameter multi-dimensional information or multi-parameter information; demodulating equipment of low cost, small volume and high sampling frequency.

The principle of the measurement dimension and principle of the sensing configuration for FBG acceleration sensors have been introduced, which could provide an important reference for the research community.

The purpose of this paper is to enhance the network lifetime of WSN. In wireless sensor network (WSN), the sensor nodes are widely deployed in a terrestrial environment to sense and evaluate the physical circumstances. The sensor node near to the sink will deplete more energy faster than other nodes; hence, there arises an energy hole and network partitioning problem in stationary sink-based WSN. Even though many mobile sink-based WSN is formulated to mitigate energy hole, inappropriate placement of sink leads to packet drop and affect the network lifetime of WSN. Therefore, it is necessary to have an efficient sink mobility approach to prevent an aforesaid problem.

In this paper, zone-based sink mobility (ZBSM) approach is proposed in which the zone formation along with controlled sink mobility is preferred for energy hole mitigation and optimal sink node placement. In ZBSM, the sink decides to move toward strongly loaded zone (SLZ) for avoiding network partitioning problems where the selection of SLZ can be carried out by using Fuzzy Logic.

The performance results confirm that the proposed scheme reduces energy consumption as well as enhances the network lifetime compared with an existing scheme.

A new optimal sink node placement is proposed to enhance the network lifetime and packet delivery ratio of WSN.

Seepage of the dam is an important safety problem, which may cause internal erosion of the structure. In the field of seepage monitoring in civil engineering, the distributed optical fiber sensing technology based on the temperature tracing method has been paid more attention due to its unique advantages of high sensitivity, good stability and high resolution. The purpose of this paper is to make a review of the existing related research, so as to facilitate the later scholars to understand and further study more systematically.

In this paper, three kinds of commonly used distributed fiber temperature measurement technologies are introduced. Based on the working principle, monitoring system, theoretical analysis, experimental research and engineering application of the fiber seepage monitoring technology, the present situation of dam seepage monitoring based on distributed fiber is reviewed in detail and their advantages and disadvantages are compared.

The thermal monitoring technology of seepage measurement depends on the accuracy of optical fiber temperature measurement (including the accuracy of the system and the rationality of the discrimination method), the correct installation of optical fiber and the quantitative analysis of temperature data. The accuracy of the current monitoring system can basically meet the existing measurement requirements, but the correct installation of optical fiber and the calibration of temperature data need to be further studied for different discrimination methods, and this field has great research value.

At present, there are many applications and research studies of optical fiber sensing in the field of structural health monitoring, and there are also reviews of related aspects. However, there is little or no review only in the field of seepage monitoring. This paper summarizes the research and application of optical fiber sensing in the field of seepage monitoring. The possibility of the gradient method to find its new prospect with the development of monitoring systems and the improvement of temperature resolution is discussed. The idea of extending the seepage monitoring method based on distributed optical fiber thermal monitoring technology to other monitoring fields is also given in the paper.

The purpose of this paper is proposed a new structure design for high performance accelerometer.

An improved sensitivity structure considering sensitivity, natural frequency and cross-axis sensitivity is established and realized. The proposed structure was designed to improve the trade-off between the sensitivity and the natural frequency of piezoresistive accelerometer and eliminate the lateral sensitivity effect by the specific configuration, which is made possible by incorporating slots into the eight-beam structure. The mechanical model and its mathematical solution are established for calculating the sensitivity and natural frequency behavior of the designed structure. The developed sensor is fabricated on the n-type single-crystal silicon wafer and packaged for experiment. The accelerometer prototype was tested in the centrifugal machine and dynamic calibration system.

The experimental results show that the sensitivity of the designed sensor is 0.213 mV/(Vg) and the natural frequency of the sensor is 14.22 kHz. Compared with some piezoresistive accelerometers in literatures, the designed sensor possesses a suitable characteristic in sensitivity, natural frequency and transverse effect, which allows its usage in measuring high frequency vibration signals.

The accelerometer with slotted eight-beam structure shows a good performance in the static and dynamic experiments and can be used in measuring high frequency vibration signals.