Warranty Data Analysis: A Review

Warranty claims and supplementary data contain useful information about product quality and reliability. Analysing such data can therefore be of benefit to manufacturers in identifying early warnings of abnormalities in their products, providing useful information about failure modes to aid design modification, estimating product reliability for deciding on warranty policy and forecasting future warranty claims needed for preparing fiscal plans. In the last two decades, considerable research has been conducted in warranty data analysis (WDA) from several different perspectives. This article attempts to summarise and review the research and developments in WDA with emphasis on models, methods and applications. It concludes with a brief discussion on current practices and possible future trends in WDA

Construction of asymmetric copulas and its application in two-dimensional reliability modelling

Copulas offer a useful tool in modelling the dependence among random variables. In the literature, most of the existing copulas are symmetric while data collected from the real world may exhibit asymmetric nature. This necessitates developing asymmetric copulas that can model such data. In the meantime, existing methods of modelling two-dimensional reliability data are not able to capture the tail dependence that exists between the pair of age and usage, which are the two dimensions designated to describe product life. This paper proposes two new methods of constructing asymmetric copulas, discusses the properties of the new copulas, and applies the method to fit two-dimensional reliability data that are collected from the real world

Optimal Warranty Period for Free-replacement Policy of Agm Batteries

The objective of this study is to analyze the suitability of the age-based warranty model and a millage based warranty model for absorbent glass mat batteries (AGM) for the automobile industry. The battery life expectancy can be assessed and described by a combination of different terms such as: state of health (SOH), deep of discharge (DOD), state of energy (SOE) and state of charge (SOC). However, using actual data from the field, the implementation of reliability engineering and statistical modeling we aim to calculate optimal limits for warranty policies that minimize warranty costs. The outcomes of this research will enable battery manufacturers, motor companies and warranty managers in decisions making strategies for cost savings in warranty projects without negatively affecting customer satisfaction

Two-dimensional Warranty Cost Analysis for Second-hand Products

In spite of the recent steady increase of the volume of the second-hand markets, often customers remain in doubt regarding the quality and durability of the secondhand products. Aiming to reduce and share this uncertainty, dealers offer warranty on their products. Offering warranty for second-hand products is a relatively new marketing strategy employed by dealers of used electronic equipment, furniture, automobiles, etc. Usually, for used products, the dealer’s expected warranty cost is a function of product reliability, past age and usage, servicing strategy and conditions and terms of the warranty policy/contract. Sometimes the offered policy is limited by two parameters, typically the product age and usage after the sale. This type of policies is referred to as two-dimensional warranty policies. In this article, we develop statistical models for estimating the dealer’s expected warranty cost for second-hand products sold with two-dimensional free repair/replacement warranty

Meeting the challenge of zero carbon homes : a multi-disciplinary review of the literature and assessment of key barriers and enablers

Within the built environment sector, there is an increasing pressure on professionals to consider the impact of development upon the environment. These pressures are rooted in sustainability, and particularly climate change. But what is meant by sustainability? It is a term whose meaning is often discussed, the most common definition taken from the Bruntland report as “sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (World Commission on Environment and Development, 1987). In the built environment, the sustainability issues within the environment, social and economic spheres are often expressed through design considerations of energy, water and waste. Given the Stern Report’s economic and political case for action with respect to climate change (Stern, 2006) and the IPCC’s Fourth Assessment Report’s confirmation of the urgency of the climate change issue and it’s root causes (IPCC, 2007), the need for action to mitigate the effects of climate change is currently high on the political agenda. Excess in carbon dioxide concentrations over the natural level have been attributed to anthropogenic sources, most particularly the burning of carbon-based fossil fuels. Over 40% of Europe’s energy and 40% of Europe’s carbon dioxide emissions arise from use of energy in buildings. Energy use in buildings is primarily for space heating, water heating, lighting and appliance use. Professionals in the built environment can therefore play a significant role in meeting targets for mitigating the effects of climate change. The UK Government recently published the Code for Sustainable Homes (DCLG, 2006). Within this is the objective of development of zero carbon domestic new build dwellings by 2016. It is the domestic zero carbon homes agenda which is the focus of this report. The report is the culmination of a research project, funded by Northumbria University, and conducted from February 2008 to July 2008, involving researchers from the Sustainable Cities Research Institute (within the School of the Built Environment) and academics, also from within the School. The aim of the project was to examine, in a systematic and holistic way, the critical issues, drivers and barriers to building and adapting houses to meet zero carbon targets. The project involved a wide range of subject specialisms within the built environment and took a multi-disciplinary approach. Practitioner contribution was enabled through a workshop. The focus of this work was to review the academic literature on the built environment sector and its capabilities to meet zero carbon housing targets. It was not possible to undertake a detailed review of energy efficiency or micro-generation technologies, the focus of the research was instead in four focussed areas: policy, behaviour, supply chain and technology.What follows is the key findings of the review work undertaken. Chapter One presents the findings of the policy and regulation review. In Chapter Two the review of behavioural aspects of energy use in buildings is presented. Chapter Three presents the findings of the review of supply chain issues. Chapter Four presents the findings of the technology review, which focuses on phase change materials. A summary of the key barriers and enablers, and areas for future research work, concludes this report in Chapter Five. Research is always a work in progress, and therefore comments on this document are most welcome, as are offers of collaboration towards solutions. The School of the Built Environment at Northumbria University strives to embed its research in practical applications and solutions to the need for a low carbon economy

Modeling the number of hidden events subject to observation delay

This paper considers the problem of predicting the number of events that have occurred in the past, but which are not yet observed due to a delay. Such delayed events are relevant in predicting the future cost of warranties, pricing maintenance contracts, determining the number of unreported claims in insurance and in modeling the outbreak of diseases. Disregarding these unobserved events results in a systematic underestimation of the event occurrence process. Our approach puts emphasis on modeling the time between the occurrence and observation of the event, the so-called observation delay. We propose a granular model for the heterogeneity in this observation delay based on the occurrence day of the event and on calendar day effects in the observation process, such as weekday and holiday effects. We illustrate this approach on a European general liability insurance data set where the occurrence of an accident is reported to the insurer with delay