Flipped $$\mathbf {g_\mu - 2}$$

We analyze the possible magnitude of the supersymmetric contribution to $$g_\mu - 2$$ g μ - 2 in a flipped SU(5) GUT model. Unlike other GUT models which are severely constrained by universality relations, in flipped SU(5) the U(1) gaugino mass and the soft supersymmetry-breaking masses of right-handed sleptons are unrelated to the other gaugino, slepton and squark masses. Consequently, the lightest neutralino and the right-handed smuon may be light enough to mitigate the discrepancy between the experimental measurement of $$g_\mu - 2$$ g μ - 2 and the Standard Model calculation, in which case they may be detectable at the LHC and/or a 250 GeV $$e^+ e^-$$ e + e - collider, whereas the other gauginos and sfermions are heavy enough to escape detection at the LHC.

Customer lifetime value models: do they predict actual behaviour?

<p>Accurate input information is the cornerstone of sound managerial decision making. Assessing the future lifetime value of customers is a key component in making accurate managerial decisions such as how to apply scarce organisation resources on retention or acquisition activities (Blattberg and Deighton, 1996). Additionally, accurate customer lifetime value (CLV) calculation can be used for effective segmentation of customers. Berger and Nasr (1998) recognised the need for an improved approach to customer lifetime valuation calculation. The model proposed by Berger and Nasr (1998) differed from historical approaches, such as the Recency, Frequency, and Monetary (RFM) method, by predicting the future state of existing customers and discounting the projected cash flow over time. Whilst the RFM model was popular as noted by Reinartz and Kumar, (2000), it was limited in accurately calculating the future value of a group of customers and was applied in segmentation classification. Berger and Nasr's (1998) model found favour in literature where subsequent contributions followed in areas; Managerial application of the model findings, alternative approaches to calculating the model inputs, and introducing alternative variables or techniques in the CLV calculation model itself. The literature confirmed Berger and Nasr's (1998) approach as suitable for examination in this study however also revealed a general lack of empirical validation for Berger and Nasr's (1998). A review of literature detailed several extensions to the theory and modelling literature on CLV and several propositions relating to this area of theory development. These were contributions mostly conceptual by nature and few supported their concepts with empirical validation. This empirical study provides an important contribution by examining the predictive accuracy of Berger and Nasr's (1998) CLV calculation model. The purpose of this research was to compare Berger and Nasr's (1998) CLV model's prediction of customer lifetime value against the actual value data over a specific period for a set cohort of residential segment consumers from a leading New Zealand energy retailer. This study goes further to examine the sensitivity of the model's calculation output to a change in input variables. The findings of this research challenge the predictive accuracy of Berger and Nasr's (1998) CLV model. The model was applied using both large (total cohort) and small (segments) customer groups to understand how what level of accuracy can be achieved in different contexts. The study identified a number of limitations such as the use of a constant retention rate, and not adequately accommodating the level of customer heterogeneity. The sensitivity of the model to change in the input variables supported Gupta, Lehmann and Stuart's (2004) research showing the retention variable was the critical input as it was the most influential on the model calculation. The marketing and discount rate variables had little to no influence on the model calculation outcome. Several propositions identified in literature on this subject were examined with many supported such as Reichheld and Sasser's (1990) observation that businesses lose 15% - 20% of their customers each year. Wyner's (1999) proposition was also supported in that the cohort when segmented demonstrated considerable different characteristics including patterns of attrition. This research presents empirical findings that will assist further theory development in the area of accurate measurement of Customer Lifetime Value (CLV) and promotes further examination of Berger and Nasr's (1998) CLV model.</p>

Customer lifetime value models: do they predict actual behaviour?

<p>Accurate input information is the cornerstone of sound managerial decision making. Assessing the future lifetime value of customers is a key component in making accurate managerial decisions such as how to apply scarce organisation resources on retention or acquisition activities (Blattberg and Deighton, 1996). Additionally, accurate customer lifetime value (CLV) calculation can be used for effective segmentation of customers. Berger and Nasr (1998) recognised the need for an improved approach to customer lifetime valuation calculation. The model proposed by Berger and Nasr (1998) differed from historical approaches, such as the Recency, Frequency, and Monetary (RFM) method, by predicting the future state of existing customers and discounting the projected cash flow over time. Whilst the RFM model was popular as noted by Reinartz and Kumar, (2000), it was limited in accurately calculating the future value of a group of customers and was applied in segmentation classification. Berger and Nasr's (1998) model found favour in literature where subsequent contributions followed in areas; Managerial application of the model findings, alternative approaches to calculating the model inputs, and introducing alternative variables or techniques in the CLV calculation model itself. The literature confirmed Berger and Nasr's (1998) approach as suitable for examination in this study however also revealed a general lack of empirical validation for Berger and Nasr's (1998). A review of literature detailed several extensions to the theory and modelling literature on CLV and several propositions relating to this area of theory development. These were contributions mostly conceptual by nature and few supported their concepts with empirical validation. This empirical study provides an important contribution by examining the predictive accuracy of Berger and Nasr's (1998) CLV calculation model. The purpose of this research was to compare Berger and Nasr's (1998) CLV model's prediction of customer lifetime value against the actual value data over a specific period for a set cohort of residential segment consumers from a leading New Zealand energy retailer. This study goes further to examine the sensitivity of the model's calculation output to a change in input variables. The findings of this research challenge the predictive accuracy of Berger and Nasr's (1998) CLV model. The model was applied using both large (total cohort) and small (segments) customer groups to understand how what level of accuracy can be achieved in different contexts. The study identified a number of limitations such as the use of a constant retention rate, and not adequately accommodating the level of customer heterogeneity. The sensitivity of the model to change in the input variables supported Gupta, Lehmann and Stuart's (2004) research showing the retention variable was the critical input as it was the most influential on the model calculation. The marketing and discount rate variables had little to no influence on the model calculation outcome. Several propositions identified in literature on this subject were examined with many supported such as Reichheld and Sasser's (1990) observation that businesses lose 15% - 20% of their customers each year. Wyner's (1999) proposition was also supported in that the cohort when segmented demonstrated considerable different characteristics including patterns of attrition. This research presents empirical findings that will assist further theory development in the area of accurate measurement of Customer Lifetime Value (CLV) and promotes further examination of Berger and Nasr's (1998) CLV model.</p>

Development of a Program for Calculating the Air Regime of a Building

The article describes the main differences between a specialized program for calculating the air regime of a building and universal software systems. Algorithms for creating a mathematical model, calculation algorithms and applications are given. A brief description of the principles of the program, the requirements for computer technology and software are given.

Rod eutectic growth in bulk undercooled melts

This article proposes an analytical model to understand the rod-growth of eutectic in the bulk undercooled melt. Based on the previous derivations of the lamellar eutectic growth models, relaxing the assumptions of small Peclet numbers, the model is derived by considering melt kinetic and thermal undercoolings. The intent of this model is to predict the transitions in eutectic pattern for conditions of the low and high growth velocity. In addition to investigation of the transition between lamellar and rod eutectic pattern, mathematical simplifications of solving Bessel function are presented as well, which is the most important priority to model calculation.