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The purpose of this paper is to theoretically analyze and experimentally demonstrate the investigation on and optimization of a distributed optical fiber sensor based on phase-sensitive optical time domain reflectometer (F-OTDR) for disturbance detection.

The F-OTDR system is investigated and optimized in two aspects: the hardware parameter and the interrogation scheme.

Based on the optimized hardware and the new interrogation scheme, the performances of the F-OTDR system have been improved greatly, compared with conventional F-OTDR system. A location accuracy of 2 m and a signal-to-noise ratio (SNR) of 16 dB have been achieved under a spatial resolution of 8 m. On the other hand, four disturbances at four different locations have been detected and located simultaneously, which is the most effective detection system with the maximum detection capability reported to date, to the best of the authors’ knowledge.

Four disturbances at four different locations have been detected and located simultaneously, which is the most effective detection system with the maximum detection capability reported to date, to the best of the authors’ knowledge. With same hardware conditions, more existing disturbances can be detected by using the new interrogation scheme, which is helpful to reduce the miss report of disturbance.

The purpose of this paper is to introduce a novel intensity-modulated fiber optic sensor for real-time intrusion detection using a fiber-optic microbend sensor and an optical time-domain reflectometer (OTDR).

The proposed system is tested using different scenarios using person/car as intruders. Experiments are conducted in the lab and in the field. In the beginning, the OTDR trace is obtained and recorded as a reference signal without intrusion events. The second step is to capture the OTDR trace with intrusion events in one or multiple sectors. This measured signal is then compared to the reference signal and processed by matrix laboratory to determine the intruded sector. Information of the intrusion is displayed on an interactive screen implemented by Visual basic. The deformer is designed and implemented using SOLIDWORKS three-dimensional computer aided design Software.

The system is tested for intrusions by performing two experiments. The first experiment is performed for both persons (>50 kg) in the lab and cars in an open field with a car moving at 60 km/h using two optical fiber sectors of lengths 200 and 500 m. For test purposes, the deformer length used in the experiment is 2 m. The used signal processing technique in the first experiment has some limitations and its accuracy is 70% after measuring and recording 100 observations. To overcome these limitations, a second experiment with another technique of signal processing is performed.

The system can perfectly display consecutive intrusions of the sectors, but in case of simultaneous intrusions of different sectors, which is difficult to take place in real situations, there will be the ambiguity of the number of intruders and the intruded sector. This will be addressed in future work. Suitable and stable laser power is required to get a suitable level of backscattered power. Optimization of the deformer is required to enhance the sensitivity and reliability of the sensor.

The proposed work enables us to benefit from the ease of implementation and the reduced cost of the intensity-modulated fiber optic sensors because it overcomes the constraints that prevent using the intensity-modulated fiber optic sensors for intrusion detection.

The proposed system is the first time long-range intensity-modulated fiber optic sensor for intrusion detection.

Describes the author's work on the development of fibre sensors and networks for monitoring trace gases such as methane, acetylene, carbon dioxide, carbon monoxide, hydrogen sulphide and for detection of spills of gasoline, diesel and organic solvents, all of which are important in environmental and safety management. As an example, a 45‐point fibre optic sensor network has been installed on a landfill site to assess the distribution of methane generation across the site. System operation is based on near‐IR absorption and is currently being extended to monitor other gases such as carbon dioxide and hydrogen sulphide. Concurrently, research is being conducted on fibre lasers for the realisation of multi‐point, multi‐gas monitoring systems. Based on other principles (periodic micro‐bending loss effects), detection of hydrocarbon fuel spills has been demonstrated at multiple locations along the length of a specially designed fibre optic cable using standard optical time domain reflectometry (OTDR) measurements.

The influence of security practices is increasingly common in the supply chain management and logistics literature. However, an under-researched area exists within the logistics service provider (LSP) selection process. The purpose of this paper is to introduce a security capability into the LSP selection process. Specifically, this research seeks to understand partner willingness to compensate and collaborate with service providers that possess a security capability.

Adaptive choice modeling is adopted to assess the influence of a security capability in the LSP selection process. This study represents the first use of this method in supply chain management and logistics research. Cluster analysis is also performed to uncover specific buyer segments along with traditional regression-based significance testing and counting analysis.

The findings indicate that security can have an important influence on the LSP selection process. In particular, the findings note a willingness to pay for a security capability in LSP selection. Applying segmentation techniques to the findings, three LSP buying segments are determined, each placing different importance and value on LSP capabilities.

This research notes an ongoing provider deficiency in security offerings. Partner firms sometimes maintain a cost focus, but others show a willingness to pay higher prices for access to partners with a security capability. Key practitioner findings include the need to include security with other traditional selection variables. The study walks the researcher and manager through the development of segments based on LSP capabilities.

This manuscript investigates logistic service provider selection. The authors detail an advanced form of conjoint analysis, adaptive conjoint modeling, for first time consideration. Additionally, this is the first study to integrate security into the LSP selection process. This is also the first study to identify a willingness to pay for a security capability.

Just as with conventional electrical cables, signals passed down optical fibres will not reach their destination if a break or improper connection is present in the fibre optic cable. Now that optical fibres are widely used in defence and communications, accurate methods of precisely locating breaks have become extremely important.

Introduction Optical sensors, and especially fibre optic sensors, offer some significant technical advantages over conventional electronic sensors. These technical advantages have been perceived to be sufficiently significant to have stimulated a large amount of research activity in the UK and elsewhere. Much of the original research has been carried out in universities and polytechnics, but there has also been considerable corporate R&D activity aimed at developing commercial products and systems. The results of much of this corporate work have not been published, except in the form of patents. Patents therefore provide a useful literature which, though of considerable interest to companies, is difficult to analyse and assimilate. For this reason, the DTI Advanced Sensors Technology Transfer Programme commissioned a study of recent optical sensor patents. The aim was to classify and analyse the patents, and to present the findings in a manner which a small or medium size instrumentation company could readily digest.

Sensor Review publishes the results of a major sensor survey.

Since the introduction of the fibre optic distributed temperature system by York in 1986, the system has been successfully applied in a number of areas. The monitoring of hot‐spots in large power transformers and electricity cables to the analysis of the curing process in large concrete structures such as dams are some examples of where the technology is being used and is providing temperature data. Other more imaginative but nevertheless potentially feasible applications range from detecting black ice on roads to the monitoring of volcanic eruptions for the purpose of disaster prevention.

To examine the range of fibre‐optic sensors available for monitoring the integrity of buildings and civil engineering structures.

Explains the need for structural monitoring and reviews the types of fibre‐optic sensors. Concentrating on elongation and temperature sensing, shows how each technology works, which companies supply the products, and gives an overview of their technical specifications.

Fibre optics are able to provide integrated, single‐point and distributed sensor systems. The fibre is a communication channel as well as a sensor, and in some systems, carries highly multiplexed data over considerable distances to a central monitoring station. The take‐up of this technology in structural sensing is helped by appropriate packaging that assists attachment to buildings. Durability and measurement stability give a continuity of measurement that was not previously possible.

An introduction to the range of sensors applicable to structural monitoring, of general interest to scientists, but particularly to civil and constructional engineers.