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Acceptable Performance (acceptable + performance)
Selected AbstractsAmalgam Electrodes for ElectroanalysisELECTROANALYSIS, Issue 8 2003Øyvind Mikkelsen Abstract Liquid mercury is a unique material for the indicator electrode in voltammetry. One reason for this is the high overvoltage for hydrogen formation, thus extending the actual potential window. Diluted amalgams are important reaction products in voltammetric (polarographic) processes, however liquid amalgams are rarely used directly as electrode material for analytical purposes. Because of the fact that voltammetry is very suitable for field and remote monitoring, issues concerning the use of mercury electrodes in environmental analyses have led to considerable research effort aimed at finding alternative tools with acceptable performance. Solid electrodes are such alternatives. Different types of electrodes are reviewed. In particular, solid amalgam electrodes are very promising, with acceptable low toxicity to be used for field measurements. Solid amalgam electrodes are easy and cheap to construct and are stable over a reasonable time up to several weeks. Assessment of the toxicity risk and the long time stability for remote and unattended monitoring is discussed. The differences between solid dental amalgam electrodes, made by using techniques known from dental clinical practice, and mercury film or mercury layer electrodes on solid substrates are reviewed. In particular the dental technique for constructing solid amalgam electrodes gives advantage because it's fast and inexpensive. Also the technique for making dental amalgam has been explored and optimized over years by dentists, giving advantage when the same technique is used for constructing electrodes. Dental amalgam electrodes has been found to act similar to a silver electrodes, but with high overvoltage towards hydrogen. This make it possible to use the dental amalgam electrode for detection of zinc, cobalt and nickel in additions to other metals like lead, copper, thallium, cadmium, bismuth, iron etc. Also the use for reducible organic compounds is expected to be promising. [source] Near optimal LQR performance for uncertain first order systemsINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2004L. Luo Abstract In adaptive control, the objective is to provide stability and acceptable performance in the face of significant plant uncertainty. However, often there are large transients in the plant output and the control signal can become excessively large. Here, we consider the first order case with the plant parameters restricted to a compact set; we show how to design a (linear time-varying) adaptive controller which provides near optimal LQR performance. This controller is periodic with each period split into two parts: during the Estimation Phase, an estimate of the optimal control signal is formed; during the Control Phase, a suitably scaled estimate of this signal is applied to the system. We demonstrate the technique with a simulation and discuss the benefits and limitations of the approach. Copyright © 2004 John Wiley & Sons, Ltd. [source] Multiple input,multiple output adaptive feedback control strategies for the active headrest system: design and real-time implementationINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 10 2003Marek Pawelczyk Abstract In this article, multiple input,multiple output adaptive feedback control techniques for acoustic noise control in a headrest system are developed. The main goal underlying their design is to provide acoustic comfort to the user, i.e. high noise attenuation level over possibly large areas at the ears. Classical Internal Model Control system does not yield acceptable performance. An approach based on estimates of the residual noise at the ears is then proposed. It is shown that increase in the number of secondary sources to operate for one channel improves the performance. The experiments of tonal noise control are performed on an originally set-up prototype of the active headrest system. The results obtained are illustrated in the promoted form of distribution of zones of quiet. Copyright © 2003 John Wiley & Sons, Ltd. [source] Efficient IP-multicast via Inmarsat BGAN, a 3GPP satellite networkINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 5 2007Paul Febvre Abstract This paper outlines a number of challenges associated with supporting IP-multicast services efficiently across the Inmarsat Broadband Global Area Network (BGAN) 3GPP-based satellite network operating over the Imarsat-4 satellite constellation. The paper presents a network architecture that extends the 3GPP reference architecture to allow IP-multicast to be delivered when the Core Network is in a 3GPP Release-4 (non-MBMS compliant) configuration. This paper further extends the service and system concepts defined in 3GPP MBMS to provide improved flexibility and accountability, and improved scalability and efficiency when operating with the Inmarsat-4 BGAN TDM/TDMA air interface. This paper describes a number of radio resource management techniques that were deployed in a test system and the validation testing that was undertaken to support multimedia distribution and VoIP-based netted communications applications. The tuning of application and system behaviour to achieve acceptable performance is described in outline. Copyright © 2007 John Wiley & Sons, Ltd. [source] Designing man-portable power generation systems for varying power demandAICHE JOURNAL, Issue 5 2008Mehmet Yunt Abstract Portable electronic devices operate at varying power demand levels. This variability of power demand must be considered explicitly in the design of man-portable power generation systems for acceptable performance and portability. In this regard, a mathematical programming based design method is proposed. The method transcribes optimal operation of the system at a given power demand into a mathematical program. The power demand specific programs are incorporated into another upper level mathematical program encoding design requirements to form a final two-stage formulation. The design and operational parameters of the power generation system comprise a solution of the formulation. Unlike designs, based on a nominal power demand, the design guarantees that each power demand and all operational requirements can be satisfied. A detailed study of a microfabricated fuel-cell based system is performed. The proposed method produces smaller designs with significantly better performances than nominal power demand based approaches. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] How about alternatives to phthalate plasticizers?JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2003Leonard G. Krauskopf Phthalate plasticizers have historically served as the preferred plasticizers to impart flexibility to PVC and several other polar polymers. They provide a desirable balance of cost and performance properties. Their acceptable and safe use is unmatched in medical appliances, food processing, and packaging applications, as well as in many other end uses. Potential alternatives do not have the historical record of acceptable performance found with phthalate plasticizers. Nevertheless, the "Precautionary Principle" has caused certain segments of society to clamor for alternates to phthalate plasticizers. This paper reviews known "non-phthalate" plasticizers and provides comparisons to the traditional "General Purpose" (GP) phthalate plasticizers; "General Purpose" plasticizers are those that impart optimum overall performance properties in PVC at lowest cost. [source] Analysis of Case-Only Studies Accounting for Genotyping ErrorANNALS OF HUMAN GENETICS, Issue 2 2007K. F. Cheng Summary The case-only design provides one approach to assess possible interactions between genetic and environmental factors. It has been shown that if these factors are conditionally independent, then a case-only analysis is not only valid but also very efficient. However, a drawback of the case-only approach is that its conclusions may be biased by genotyping errors. In this paper, our main aim is to propose a method for analysis of case-only studies when these errors occur. We show that the bias can be adjusted through the use of internal validation data, which are obtained by genotyping some sampled individuals twice. Our analysis is based on a simple and yet highly efficient conditional likelihood approach. Simulation studies considered in this paper confirm that the new method has acceptable performance under genotyping errors. [source] CRIMINALIZATION OF MEDICAL ERROR: WHO DRAWS THE LINE?ANZ JOURNAL OF SURGERY, Issue 10 2007Sidney W. A. Dekker As stakeholders struggle to reconcile calls for accountability and pressures for increased patient safety, criminal prosecution of surgeons and other health-care workers for medical error seems to be on the rise. This paper examines whether legal systems can meaningfully draw a line between acceptable performance and negligence. By questioning essentialist assumptions behind ,crime' or ,negligence', this paper suggests that multiple overlapping and partially contradictory descriptions of the same act are always possible, and even necessary, to approximate the complexity of reality. Although none of these descriptions is inherently right or wrong, each description of the act (as negligence, or system failure, or pedagogical issue) has a fixed repertoire of responses and countermeasures appended to it, which enables certain courses of action while excluding others. Simply holding practitioners accountable (e.g. by putting them on trial) excludes any beneficial effects as it produces defensive posturing, obfuscation and excessive stress and leads to defensive medicine, silent reporting systems and interference with professional oversight. Calls for accountability are important, but accountability should be seen as bringing information about needed improvements to levels or groups that can do something about it, rather than deflecting resources into legal protection and limiting liability. We must avoid a future in which we have to turn increasingly to legal systems to wring accountability out of practitioners because legal systems themselves have increasingly created a climate in which telling each other accounts openly is less and less possible. [source] | |||||||||||||