Warranty cost analysis for products with a dormant state

Most building services products are installed while a building is constructed, but they are not operated until the building is commissioned. The warranty of the products may cover the time starting from their installation to the end of the warranty period. Prior to the commissioning of the building, the products are at a dormant mode (i.e., not operated) but protected by the warranty. For such products, both the usage intensity and the failure patterns are different from those with continuous usage intensity and failure patterns. This paper develops warranty cost models for repairable products with a dormant mode from both the manufacturer's and buyer's perspectives. Relationships between the failure patterns at the dormant mode and at the operational mode are also discussed. Numerical examples and sensitivity analysis are used to demonstrate the applicability of the methodology derived in the paper.

Cost-benefit evaluation of routine influenza immunisation in people 65-74 years of age

OBJECTIVES: To determine the cost-effectiveness of influenza vaccination in people aged 65-74 years in the absence of co-morbidity. DESIGN: Primary research: randomised controlled trial. SETTING: Primary care. PARTICIPANTS: People without risk factors for influenza or contraindications to vaccination were identified from 20 general practitioner (GP) practices in Liverpool in September 1999 and invited to participate in the study. There were 5875/9727 (60.4%) people aged 65-74 years identified as potentially eligible and, of these, 729 (12%) were randomised. INTERVENTION: Participants were randomised to receive either influenza vaccine or placebo (ratio 3:1), with all individuals receiving pneumococcal vaccine unless administered in the previous 10 years. Of the 729 people randomised, 552 received vaccine and 177 received placebo; 726 individuals were administered pneumococcal vaccine. MAIN OUTCOME MEASURES AND METHODOLOGY OF ECONOMIC EVALUATION: GP attendance with influenza-like illness (ILI) or pneumonia (primary outcome measure); or any respiratory symptoms; hospitalisation with a respiratory illness; death; participant self-reported ILI; quality of life (QoL) measures at 2, 4 and 6 months post-study vaccination; adverse reactions 3 days after vaccination. A cost-effectiveness analysis was undertaken to identify the incremental cost associated with the avoidance of episodes of influenza in the vaccination population and an impact model was used to extrapolate the cost-effectiveness results obtained from the trial to assess their generalisability throughout the NHS. RESULTS: In England and Wales, weekly consultations for influenza and ILI remained at baseline levels (less than 50 per 100,000 population) until week 50/1999 and then increased rapidly, peaking during week 2/2000 with a rate of 231/100,000. This rate fell within the range of 'higher than expected seasonal activity' of 200-400/100,000. Rates then quickly declined, returning to baseline levels by week 5/2000. The predominant circulating strain during this period was influenza A (H3N2). Five (0.9%) people in the vaccine group were diagnosed by their GP with an ILI compared to two (1.1%) in the placebo group [relative risk (RR), 0.8; 95% confidence interval (CI) = 0.16 to 4.1]. No participants were diagnosed with pneumonia by their GP and there were no hospitalisations for respiratory illness in either group. Significantly fewer vaccinated individuals self-reported a single ILI (4.6% vs 8.9%, RR, 0.51; 95% CI for RR, 0.28 to 0.96). There was no significant difference in any of the QoL measurements over time between the two groups. Reported systemic side-effects showed no significant differences between groups. Local side-effects occurred with a significantly increased incidence in the vaccine group (11.3% vs 5.1%, p = 0.02). Each GP consultation avoided by vaccination was estimated from trial data to generate a net NHS cost of 174 pounds. CONCLUSIONS: No difference was seen between groups for the primary outcome measure, although the trial was underpowered to demonstrate a true difference. Vaccination had no significant effect on any of the QoL measures used, although vaccinated individuals were less likely to self-report ILI. The analysis did not suggest that influenza vaccination in healthy people aged 65-74 years would lead to lower NHS costs. Future research should look at ways to maximise vaccine uptake in people at greatest risk from influenza and also the level of vaccine protection afforded to people from different age and socio-economic populations.

Is influenza vaccination cost effective for healthy people between ages 65 and 74 years? A randomised controlled trial

The aim of this study was to determine the cost effectiveness of influenza vaccination for healthy people aged 65-74 years living in the UK. People without risk factors for influenza (chronic heart, lung or renal disease, diabetic, immuno-suppressed or those living in an institution) were identified from 20 general practitioner (GP) practices in Liverpool in September 1999. 729/5875 (12.4%) eligible individuals were recruited and randomised to receive either influenza vaccine or placebo (ratio 3: 1)! with all participants receiving 23-valent-pneumococcal polysaccharide vaccine unless already administered. The primary analysis was the frequency of influenza as recorded by a GP diagnosis of pneumonia or influenza like illness. In 2000, the UK vaccination policy was changed with influenza vaccine becoming available. for all people aged 65 years and over irrespective of risk. As a consequence of this policy change. the study had to be fundamentally restructured and only results obtained over a one rather than the originally planned two-year randomised controlled trial framework were used. Results from 1999/2000 demonstrated no significant difference between groups for the primary outcome (relative risk 0.8, 95%, CI 0.16-4.1). In addition. there were no deaths or hospitalisations for influenza associated respiratory illness in either group. The subsequent analysis. using both national and local sources of evidence, estimated the following cost effectiveness indicators: (1) incremental NHS cost per GP consultation avoided = pound2000; (2) incremental NHS cost per hospital admission avoided = pound61,000: (3) incremental NHS cost per death avoided = pound1.900.000 and (4) incremental NHS cost per QALY gained = pound304,000. The analysis suggested that influenza vaccination in this Population would not be cost effective. (C) 2004 Elsevier Ltd. All rights reserved.

Cost-effectiveness of a preventive counseling and support package for postnatal depression

Objectives: This study reports the cost-effectiveness of a preventive intervention, consisting of counseling and specific support for the mother-infant relationship, targeted at women at high risk of developing postnatal depression. Methods: A prospective economic evaluation was conducted alongside a pragmatic randomized controlled trial in which women considered at high risk of developing postnatal depression were allocated randomly to the preventive intervention (n = 74) or to routine primary care (n = 77). The primary outcome measure was the duration of postnatal depression experienced during the first 18 months postpartum. Data on health and social care use by women and their infants up to 18 months postpartum were collected, using a combination of prospective diaries and face-to-face interviews, and then were combined with unit costs ( pound, year 2000 prices) to obtain a net cost per mother-infant dyad. The nonparametric bootstrap method was used to present cost-effectiveness acceptability curves and net benefit statistics at alternative willingness to pay thresholds held by decision makers for preventing 1 month of postnatal depression. Results: Women in the preventive intervention group were depressed for an average of 2.21 months (9.57 weeks) during the study period, whereas women in the routine primary care group were depressed for an average of 2.70 months (11.71 weeks). The mean health and social care costs were estimated at 2,396.9 pound per mother-infant dyad in the preventive intervention group and 2,277.5 pound per mother-infant dyad in the routine primary care group, providing a mean cost difference of 119.5 pound (bootstrap 95 percent confidence interval [Cl], -535.4, 784.9). At a willingness to pay threshold of 1,000 pound per month of postnatal depression avoided, the probability that the preventive intervention is cost-effective is .71 and the mean net benefit is 383.4 pound (bootstrap 95 percent Cl, -863.3- pound 1,581.5) pound. Conclusions: The preventive intervention is likely to be cost-effective even at relatively low willingness to pay thresholds for preventing 1 month of postnatal depression during the first 18 months postpartum. Given the negative impact of postnatal depression on later child development, further research is required that investigates the longer-term cost-effectiveness of the preventive intervention in high risk women.

A cost-effective high-throughput digital system for observation and acquisition of animal behavioral data

We have designed and implemented a low-cost digital system using closed-circuit television cameras coupled to a digital acquisition system for the recording of in vivo behavioral data in rodents and for allowing observation and recording of more than 10 animals simultaneously at a reduced cost, as compared with commercially available solutions. This system has been validated using two experimental rodent models: one involving chemically induced seizures and one assessing appetite and feeding. We present observational results showing comparable or improved levels of accuracy and observer consistency between this new system and traditional methods in these experimental models, discuss advantages of the presented system over conventional analog systems and commercially available digital systems, and propose possible extensions to the system and applications to non-rodent studies.

A practical low cost architecture for a MB-OFDM equalizer (ECMA-368)

The relative fast processing speed requirements in Wireless Personal Area Network (WPAN) consumer based products are often in conflict with their low power and cost requirements. In order to solve this conflict the efficiency and cost effectiveness of these products and the underlying functional modules become paramount. This paper presents a low-cost, simple, yet high performance solution for the receiver Channel Estimator and Equalizer for the Mutiband OFDM (MB-OFDM) system, particularly directed to the WiMedia Consortium Physical Later (ECMA-368) consumer implementation for Wireless-USB and Fast Bluetooth. In this paper, the receiver fixed point performance is measured and the results indicate excellent performance compared to the current literature(1).

Low-cost optical tracking for immersive collaboration in the CAVE using the Wii remote

We present a novel way of interacting with an immersive virtual environment which involves inexpensive motion-capture using the Wii Remote®. A software framework is also presented to visualize and share this information across two remote CAVETM-like environments. The resulting applications can be used to assist rehabilitation by sending motion information across remote sites. The application’s software and hardware components are scalable enough to be used on desktop computer when home-based rehabilitation is preferred.

An empirical study of process-related attributes in segmented software cost-estimation relationships

Parametric software effort estimation models consisting on a single mathematical relationship suffer from poor adjustment and predictive characteristics in cases in which the historical database considered contains data coming from projects of a heterogeneous nature. The segmentation of the input domain according to clusters obtained from the database of historical projects serves as a tool for more realistic models that use several local estimation relationships. Nonetheless, it may be hypothesized that using clustering algorithms without previous consideration of the influence of well-known project attributes misses the opportunity to obtain more realistic segments. In this paper, we describe the results of an empirical study using the ISBSG-8 database and the EM clustering algorithm that studies the influence of the consideration of two process-related attributes as drivers of the clustering process: the use of engineering methodologies and the use of CASE tools. The results provide evidence that such consideration conditions significantly the final model obtained, even though the resulting predictive quality is of a similar magnitude.

Design issues toward a cost effective physical layer for multiband OFDM (ECMA-368) in consumer products

The creation of Wireless Personal Area Networks (WPANs) offers the Consumer Electronics industry a mechanism to truly unwire consumer products, leading to portability and ease of installation as never seen before. WPAN's can offer data-rates exceeding those that are required to convey high quality broadcast video, thus users can easily connect to high quality video for multimedia presentations in education, libraries, advertising, or have a wireless connection at home. There have been many WPAN proposals, but this paper concentrates on ECMA-368 as this standard has the largest industrial and implementers' forum backing. With the aim to effective consumer electronic define and create cost equipment this paper discusses the technology behind ECMA-368 physical layer, the design freedom availabilities, the required processing, buffer memory requirements and implementation considerations while concentrating on supporting all the offered data-rates(1).

Comparison of the computational cost of a Monte Carlo and deterministic algorithm for computing bilinear forms of matrix powers

In this paper we consider bilinear forms of matrix polynomials and show that these polynomials can be used to construct solutions for the problems of solving systems of linear algebraic equations, matrix inversion and finding extremal eigenvalues. An almost Optimal Monte Carlo (MAO) algorithm for computing bilinear forms of matrix polynomials is presented. Results for the computational costs of a balanced algorithm for computing the bilinear form of a matrix power is presented, i.e., an algorithm for which probability and systematic errors are of the same order, and this is compared with the computational cost for a corresponding deterministic method.

Assessing the environmental performance of English arable and livestock holdings using data from the Farm Accountancy Data Network (FADN)

Agri-environment schemes (AESs) have been implemented across EU member states in an attempt to reconcile agricultural production methods with protection of the environment and maintenance of the countryside. To determine the extent to which such policy objectives are being fulfilled, participating countries are obliged to monitor and evaluate the environmental, agricultural and socio-economic impacts of their AESs. However, few evaluations measure precise environmental outcomes and critically, there are no agreed methodologies to evaluate the benefits of particular agri-environmental measures, or to track the environmental consequences of changing agricultural practices. In response to these issues, the Agri-Environmental Footprint project developed a common methodology for assessing the environmental impact of European AES. The Agri-Environmental Footprint Index (AFI) is a farm-level, adaptable methodology that aggregates measurements of agri-environmental indicators based on Multi-Criteria Analysis (MCA) techniques. The method was developed specifically to allow assessment of differences in the environmental performance of farms according to participation in agri-environment schemes. The AFI methodology is constructed so that high values represent good environmental performance. This paper explores the use of the AFI methodology in combination with Farm Business Survey data collected in England for the Farm Accountancy Data Network (FADN), to test whether its use could be extended for the routine surveillance of environmental performance of farming systems using established data sources. Overall, the aim was to measure the environmental impact of three different types of agriculture (arable, lowland livestock and upland livestock) in England and to identify differences in AFI due to participation in agri-environment schemes. However, because farm size, farmer age, level of education and region are also likely to influence the environmental performance of a holding, these factors were also considered. Application of the methodology revealed that only arable holdings participating in agri-environment schemes had a greater environmental performance, although responses differed between regions. Of the other explanatory variables explored, the key factors determining the environmental performance for lowland livestock holdings were farm size, farmer age and level of education. In contrast, the AFI value of upland livestock holdings differed only between regions. The paper demonstrates that the AFI methodology can be used readily with English FADN data and therefore has the potential to be applied more widely to similar data sources routinely collected across the EU-27 in a standardised manner.

Solving complex optimal control problems at no cost with PSOPT

This paper introduces PSOPT, an open source optimal control solver written in C++. PSOPT uses pseudospectral and local discretizations, sparse nonlinear programming, automatic differentiation, and it incorporates automatic scaling and mesh refinement facilities. The software is able to solve complex optimal control problems including multiple phases, delayed differential equations, nonlinear path constraints, interior point constraints, integral constraints, and free initial and/or final times. The software does not require any non-free platform to run, not even the operating system, as it is able to run under Linux. Additionally, the software generates plots as well as LATEX code so that its results can easily be included in publications. An illustrative example is provided.