Remaining useful life in theory and practice

Remaining useful life (RUL) is nowadays in fashion, both in theory and applications. Engineers use it mostly when they have to decide whether to do maintenance, or to delay it, due to production requirements. Most often, it is assumed that in later life of an equipment (in wear-out period), the hazard function is increasing, and then the expected RUL, μ(t), is decreasing. We noticed that the standard deviation of RUL, σ(t), is also decreasing, which was expected and known, but that the ratio σ(t)/μ(t) is also increasing, which was a surprise. Initiated by this observation, we have proved that under some general conditions, which include Weibull distribution with shape parameter  > 1, this is indeed the case. Even more, we have proved that the limiting distribution of standardized RUL is exponential, so that the variability of RUL is relatively large. The role of condition monitoring in the evaluation of RUL is discussed. Various models for RUL depending on covariates are considered.     

Economic factors affecting the increase in obesity in the United States: Differential response to price

A sharp increase in obesity during the last 15 years in the United States became one of the nation’s main public health problems. The theory of rational addiction seems to explain human behavior in food consumption leading to obesity reasonably well. The interesting thing about our results is that the tax policy, normally used to correct various distortions, is to serve in this case as the preventive policy: additional taxes on future prices of the addictive (sweet) foods contribute to lower sugar consumption and BMI at present time. On the other hand, increasing education level is usually considered a preventive type of policy. In this case, it leads to lowering the levels of the BMI in already overweight and obese population.     

Globalisation and Obesity

The WHO has recently announced the global obesity epidemic. An economic model is developed in which globalisation factors generate health externalities and contribute to global obesity growth. The unbalanced panel data set contains the information for 79 countries over the period 1986–2008. Fixed‐effects panel data estimation and quantile regression analysis were used to analyse the data. The fixed‐effects panel model results indicate that the impact of trade openness and the globalisation social index (GSI) on global obesity rates is positive and significant, which is consistent with prior expectations, while surprisingly the foreign direct investments (FDI) has no impact on global obesity. While these results are interesting, they are hiding the effect of globalisation processes across the conditional distribution of the obesity variable. The use of quantile regression uncovered that the impact of the FDI and the GSI on low and average quantiles (low and average obesity rates in our sample) is positive and significant, while high quantiles are not affected. Since low and average quantiles (low and average obesity rates) are representative of the less‐ and medium‐developed countries, this result implies that social globalisation and FDI adversely impact obesity in less‐to‐medium developed countries. Trade openness generally has no impact on changes in obesity rates across quantiles.     

Assessing the role of futures position substitutability in a monthly slaughtered pork factor demand by US processors: a cointegrated VAR model approach

This article combines cointegrated VAR modelling with basic neoclassical production microeconomics in a new way that tests for, and illuminates the empirical nature of, the monthly US pork processing sector’s factor demand for slaughtered pork. Statistical evidence strongly suggests that the US pork processing sector has a Hicksian Cobb–Douglas slaughtered pork demand that arises from applying Shephard’s lemma to the sector’s cost function and that US pork processors treat slaughtered pork and related futures positions as close factor substitutes. In the wake of major and ongoing futures market events and trends, this study establishes and statistically tests a theoretical link between futures price movements and impacts on the underlying slaughtered pork market through monthly formation of US pork processors’ factor demand for slaughtered pork. Evidence suggests that demand agents shift between demands for the two substitutes based on movements in the slaughter/futures price ratio that results in a market-stabilizing cushion against sharp pork price movements such as those observed in the late-1990s. Statistical and diagnostic evidence suggests that our modelled non-experimental data and estimated Hicksian demand that arose from the cointegrated VAR model’s cointegration space met Haavelmo’s setting of passive variables and associated ceteris paribus conditions.     

Risk assessment for loader- and dozer-related fatal incidents in U.S. mining

The paper presents the results of research aimed at developing a risk assessment process that can be used to more thoroughly characterise risks associated with loader- and dozer-related fatal incidents in US mining. The assessment is based on historical data obtained from the US Mine Safety and Health Administration investigation reports, which includes 77 fatal incidents that occurred from 1995 to 2006. The Preliminary Hazard Assessment method is used in identifying and quantifying risks. Risk levels are then developed using a pre-established risk matrix that ranks them according to probability and severity. The resulting assigned risk value can then be used to prioritise risk control strategies. A total of 10 hazards were identified for loaders. The hazards 'failure to follow adequate maintenance procedure' and 'failure of mechanical/electrical/hydraulic components' were the most severe and frequent hazards and they fell into the category of 'high' risk. The same number of hazards was identified for dozers. The hazard 'failure to identify adverse site/geological conditions' was the most severe and frequent hazard and it fell into the category of 'high' risk.     

Reputation as Matching Identities and Images: Extending Davies and Chun's (2002) Research on Gaps between the Internal and External Perceptions of the Corporate Brand

Corporate reputation is defined as a construct representing aggregated perceptions of people in and around companies. A corporate personality scale was developed to measure identities as internal perceptions and images as external perceptions with the same instrument. We report here an application of this instrument and the replication of a previous study conducted by Davies and Chun in 2002 (Corporate reputation review 5(2/3): 144–158), by comparing two similar companies operating in the same industry. Perceptions of employees, students, journalists and professional colleagues were measured for each company. The reputations of the two companies were different in synchronization of perceptions of respondent groups for each company (one high and one low) and in their comparative scores from different respondent groups. The study discovered that two companies could be equally successful in performance while their reputations can be significantly different. The second significant theoretical implication of the study was the finding that a composite, aggregate measure of a corporate reputation can obscure as much as reveal perceptions of different valuing groups. The main practical implication of the study is that companies can achieve comparable performances despite having different personalities both in profile and in coherence. This implies that executives need to observe their organizations through various views, which should allow them more freedom of action and experimentation.     

Dynamic Interrelationships in Hard Wheat Basis Markets

Basis values for hard red spring (HRS) wheat have escalated radically, experienced extraordinary levels of volatility (risk), were subject to a squeeze during 2008, and all these have important implications for market participants. These are particularly important to marketers in the Northern Great Plains in the United States, as well as for Canadian marketers as they confront deregulation in wheat marketing and will be exposed to these risks. The purpose of this paper is to analyze the dynamic relationships and interdependencies among terminal market basis values for milling. Specifically, we seek to identify factors impacting basis values for 13%, 14%, and 15% protein HRS wheat in addition to the intermarket wheat spread between Minneapolis and Kansas City wheat futures. We specify a vector autoregression (VAR) model to explore these relationships. Exogenous structural variables are specified in addition to dynamic interrelationships including seasonal and intertemporal variability and dynamic interdependencies among these markets and relationships. Results of interest are that: (1) basis values for these markets have been trending up and have become more volatile; (2) factors impacting this variability are the protein level in HRS, production of hard red winter (HRW), and Canadian wheat (on high protein basis); (3) HRW protein supplies are not significant in the basis equations, but, do impact the intermarket wheat futures spread; (4) quality factors have a significant impact on basis values, notably vomitoxin, falling numbers, and absorption. Dynamic interrelations are also important in that all prices converge quickly toward a long‐term equilibrium. In addition, there are seasonal impacts, dynamic basis interactions, trends, and lagged impacts of protein levels.     

Sanitary and phytosanitary measures in international trade: policy considerations vs. economic reasoning

Sanitary and phytosanitary (SPS) measures are one form of non‐tariff international trade barrier with the objective of requiring consumer and intermediate goods to be safe and to provide information to protect consumers from deceptive practices. However, such barriers could severely restrict trade. The central strategy of the World Trade Organization's (WTO) SPS Agreement is to use science to distinguish between those SPS measures consistent with the Agreement and those in violation of the Agreement. SPS measures belong to what is known as trans‐science questions or questions which can be asked of science and yet which cannot be answered by science. Because of the presence of scientific uncertainty, science policies adopted by members should be identified by the WTO. WTO panels should not, however, establish scientific policies. Prohibitive measures would seem rather incompatible with the role the WTO assumed trying to promote free trade. Rather, facilitating the distribution of available information regarding SPS and food safety risk, or a lack of it, to consumers in importing countries would help them to make better informed decisions according to their own preferences and risk aversion.     

Innovative methods in assessing political risk for business internationalization

Political risk assessment, together with portfolio analysis, has become an important part of international business investment decision making. In this paper, by using different knowledge discovery techniques, we attempt to assess the relevance and actionability of ‘good governance’ indicators in political risk assessment. For that purpose, we have integrated good governance indicators data with political instability classification from the Political Instability Task Force (PITF) research. From this study, two models that capture the intuitive reasoning of investors have been developed. The usefulness of the models has been evaluated by comparison with factual investment data. Our findings suggest that quantitative indicators of good governance may provide the basis for accurate and meaningful models for the assessment and prediction of political risk.