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With a flourish of wireless technologies, indoor localization is becoming an emerging topic for crucial practical research including homeland security, police patrolling, machinery fault-detection, target tracking, etc. Generally speaking, indoor localization technology involves three primary types of methodologies, namely range-based localization, fingerprint-based localization and inertial localization. This paper is aimed to present an overview of these prominent indoor localization techniques and the state-of-the-art solutions. To manifest this important topic, the general localization mechanisms are analyzed. Finally, performance requirements such as accuracy, cost, robustness are presented for benchmarking localization system performances. [ABSTRACT FROM AUTHOR]

Applications that involve point-to-point routing of analog signals have benefited from the excellent propagation characteristics of optical fiber. Fiber-optic links that remote RF signals to and from phased-array radar antennas must meet especially stringent performance requirements. The past decade has seen significant progress in the performance of the fiber-optic links that distribute RF signals in antenna-remoting applications, as well as in cellular communications and cable television signal distribution networks. This article reviews the present state of the art in RF fiber-optic links [ABSTRACT FROM PUBLISHER]

Allocating resources for multimedia traffic flows with real-time performance requirements is an important challenge for future packet networks. However, in large-scale networks, individually managing each traffic flow on each of its traversed routers has fundamental scalability limitations, in both the control plane's requirements for signaling, state management, and admission control, and the data plane's requirements for per-flow scheduling mechanisms. In this paper, we develop a scalable architecture and algorithm for quality-of-service management termed egress admission control. In our approach, resource management and admission control are performed only at egress routers, without any coordination among backbone nodes or per-flow management. Our key technique is to develop a framework for admission control under a general “black box” model, which allows for cross traffic that cannot be directly measured, and scheduling policies that may be ill-described across many network nodes. By monitoring and controlling egress routers' class-based arrival and service envelopes, we show how network services can be provisioned via scalable control at the network edge. We illustrate the performance of our approach with a set of simulation experiments using highly bursty traffic flows and find that despite our use of distributed admission control, our approach is able to accurately control the system's admissible region under a wide range of conditions [ABSTRACT FROM PUBLISHER]

Management of performance requirements is a major challenge for information systems as well as other software systems. This is because performance requirements (e.g., "a student records system should have good response time for registering students") can have a global impact on the target system. In addition, there are interactions and trade-offs among performance requirements, other nonfunctional requirements (NFRs, or software quality attributes, e.g., accuracy), and the numerous alternatives for the target system. To provide a systematic approach to managing performance requirements, this paper presents a "Performance Requirements Framework" (PeRF) It integrates and catalogues a variety of kinds of knowledge of information systems and performance These include performance concepts, Software Performance Engineering (SPE) principles for "building performance into" systems, and information systems development knowledge (including requirements, design, implementation, and performance). In addition, layered structures organize performance knowledge and the development process. All this knowledge is represented using an existing goal-oriented approach, the "NFR Framework," which offers a developer-directed graphical treatment for stating NFRs, analyzing and interrelating them, and determining the impact of decisions upon NFRs. This approach allows customized solutions to be built, taking into account the characteristics of the particular domain. The use of PeRF in managing performance requirements is illustrated in a study of performance requirements and other NFRs for a university's student records system. This paper concludes with a summary of other studies of information systems, tool support, and directions for future work. [ABSTRACT FROM AUTHOR]

The nonlinearities generated by wide-band, high-current photodetectors are discussed in the context of the performance of an externally modulated analog radio-frequency fiber-optic link. The quantitative impart of the detector's third-order intermodulation product intercept (IP3) on the link's spur-free dynamic range is analyzed. Waveguide p-i-n photodiodes were developed to specifically address these stringent IP3 goals. The IP3 was measured using a four laser heterodyne system resulting in an IP3 of 27 dBm measured at a center frequency of 20 GHz with 20 mA of de photocurrent. The authors believe that this is the highest photodetector IP3 reported to date at these operating conditions [ABSTRACT FROM PUBLISHER]