Modified maximum likelihood estimation for rayleigh distribution

For defining a Modified Maximum Likelihood Estimate of the scale parameter of Rayleigh distribution, a hyperbolic approximation is used instead of linear approximation for a function which appears in the Maximum Likelihood equation. This estimate is shown to perform better, in the sense of accuracy and simplicity of calculation, than the one based on linear approximation for the same function. Also the estimate of the scale parameter obtained is shown to be asymptotically unbiased. Numerical computation for random samples of different sizes from Rayleigh distribution, using type I1 censoring is done and is shown to be better than that obtained by Lee et al. (1980)     

Making Inter-country Comparison of Life Expectancy Inequality Sensitive

Two populations with the sameoverall longevity but different age andage-specific-mortality profiles may produce avariety of differences in terms of issues thatare relevant for development policy. A simplemethod of comparing countries has beensuggested in this paper, which is sensitive tosome of these differences that are usuallyhidden under life expectancy figures. In theprocess, some of the recent attempts inadjusting life expectancy for `inequality' havebeen critically examined.     

Heterogeneous Submission Behavior and its Implications for Success in Innovation Contests with Public Submissions

Innovation contests are increasingly adopting a format where submissions are viewable by all contestants and the information structure changes during the contest. In such an “unblind” format, contestants must weigh the costs of revealing their submissions against the benefits of improving their submissions through emerging information. We take a closer look at how contestants solve problems in innovation contests with public submission of solutions—that is, unblind contests, by examining the implications of their submission behavior for contest outcomes. We analyze the submission behavior in terms of three dimensions: the position of first submission by the contestant, the number of submissions the contestant makes, and the length of active participation by the contestant. The econometric analysis of a large dataset of unblind innovation contests and participating contestants indicates that, despite the potential for free riding and intellectual property loss from disclosure of submissions, contestants who have a lower position of first submission are more likely to succeed in the contest. Further, we find some evidence of a curvilinear relationship between a contestant's number of submissions and her likelihood of success, indicating a potential “quality–quantity” trade‐off in unblind innovation contests. Finally, our findings indicate that increasing the length of participation in a contest has a positive effect on a contestant's likelihood of success. Departing from prior studies on innovation contests, where a contestant's success is assumed to be a function of her prior experience and problem‐solving skills, our study provides new empirical evidence that, in innovation contests with public submissions, the submission behavior of a contestant also plays an explanatory role in a contestant's success.     

Trust,Social Networks and Subjective Wellbeing in China

Using data from the World Values Survey, this study examines the associations among trust, social networks and subjective wellbeing in China. We address the endogenous nature of trust and social networks, and examine how these elements of social capital affect subjective wellbeing. We also explore the interplay between trust and social networks. Existing literature suggests that trust and social networks positively impact wellbeing, with one strand of the literature suggesting that in developed countries social capital is a stronger determinant of wellbeing than income. However, we find that this is not the case for China (a developing country) where the effects of trust and social networks on wellbeing are found to be relatively weaker compared to the effect of income.     

Study on lumbar kinematics and the risk of low back disorder in female university students by using shoes of different heel heights

The study was taken up to investigate the effects of heel heights on lumbar kinematics and the risk of Low Back Disorder (LBD) in females. Nineteen female university students (24.5 ± 3.36 yrs) volunteered in the study. Lumbar kinematics was measured by using Industrial Lumbar Motion Monitor (iLMM). The volunteers were asked to walk for a distance of 50 meters in 3 different given conditions i.e bare foot (Heel 0), with flat heels (Heel 1) and with high heels (Heel 2). Heights of Heel 1 and Heel 2 were 1.5 ± 0.84 cm and 5.5 ± 1.70 cm respectively. The Lumbar kinematic parameters studied were- Average Twisting Velocity (ATV), Maximum Sagital Flexion (MSF) and Maximum Lateral Velocity (MLV). It was observed that all the above mentioned Lumbar kinematics - ATV, MSF and MLV increases with increase of heel heights, which in turn increases the risk of LBD. As a result of increase in Lumbar kinematic values with increase in heel heights, LBD risk has also increased. Mean and SD of the LBD risk with Heel 0, Heel 1 and Heel 2 were 16.79 ± 6.04%, 19.00 ± 7.38% and 22.11 ± 6.98% respectively. Lower stature with high heels showed higher risk of LBD than the higher stature with high heels.     

Managing the Performance Trade‐Offs from Partner Integration: Implications of Contract Choice in R&D Projects

Formal contracts represent an important governance instrument with which firms exercise control of and compensate partners in R&D projects. The specific type of contract used, however, can vary significantly across projects. In some, firms' govern partnering relationships through fixed‐price contracts, whereas in others, firms' use more flexible time and materials or performance‐based contracts. How do these choices affect the costs and benefits that arise from greater levels of partner integration? Furthermore, how are these relationships affected when the choice of contract is misaligned with the scope and objectives of the partnering relationship? Our study addresses these questions using data from 172 R&D projects that involve partners. We find that, (i) greater partner integration is associated with higher project costs for all contract types; (ii) greater partner integration is associated with higher product quality only in projects that adopt more flexible time and materials or performance‐based contracts; and (iii) in projects where the choice of contract is misaligned with the scope and objectives of the partnering relationship, greater partner integration is associated with higher project costs, but not with higher product quality. Our results shed light on the subtle interplay between formal and relational contracting. They have important implications for practice, with respect to designing optimal governance structures in partnered R&D projects.     

Shannon Entropy for Quantifying Uncertainty and Risk in Economic Disparity

The rise in economic disparity presents significant risks to global social order and the resilience of local communities. However, existing measurement science for economic disparity (e.g., the Gini coefficient) does not explicitly consider a probability distribution with information, deficiencies, and uncertainties associated with the underlying income distribution. This article introduces the quantification of Shannon entropy for income inequality across scales, including national‐, subnational‐, and city‐level data. The probabilistic principles of Shannon entropy provide a new interpretation for uncertainty and risk related to economic disparity. Entropy and information‐based conflict rise as world incomes converge. High‐entropy instances can resemble both happy and prosperous societies as well as a socialist–communist social structure. Low entropy signals high‐risk tipping points for anomaly and conflict detection with higher confidence. Finally, spatial–temporal entropy maps for U.S. cities offer a city risk profiling framework. The results show polarization of household incomes within and across Baltimore, Washington, DC, and San Francisco. Entropy produces reliable results at significantly reduced computational costs than Gini coefficients.     

Demand Forecast Sharing in Supply Chains

This paper examines the incentives of a manufacturer and a retailer to share their demand forecasts. The demand at the retailer is a linearly decreasing function of price. The manufacturer sets the wholesale price first, and the retailer sets the retail price after observing the wholesale price. Both players set their prices based on their forecasts of demand. In the make‐to‐order scenario, the manufacturer sets the production quantity after observing the actual demand; in the make‐to‐stock scenario, the manufacturer sets the production quantity before the demand is realized. In the make‐to‐order scenario, we show that sharing the forecast unconditionally by the retailer with the manufacturer benefits the manufacturer but hurts the retailer. We also demonstrate that a side payment contract cannot induce Pareto‐optimal information sharing equilibrium, but a discount based wholesale price contract can. The social welfare as well as consumer surplus is higher under the discount contract, compared with under no information sharing. In the make‐to‐stock scenario, the manufacturer realizes additional benefits in the form of savings in inventory holding and shortage costs when forecasts are shared. If the savings from inventory holding and shortage costs because of information sharing are sufficiently high, then a side payment contract that induces Pareto‐optimal information sharing is feasible in the make‐to‐stock scenario. We also provide additional managerial insights with the help of a computational study.     

Risk and protective factors in problem gambling: an examination of psychological resilience

Psychological resilience – successful adaptation when faced with adversity – is a product of the balance of risk and protective factors relevant to an outcome. This study examined if protective factors (perceived resilience; mindfulness; grit; self-efficacy) explained variance in problem gambling tendencies (assessed with the Problem Gambling Severity Index) beyond the HEXACO personality traits (honesty-humility, emotionality, extraversion, agreeableness, conscientiousness, openness to experience) and risk factors for problem gambling (gender; age; socio-economic status; high frequency gambling behaviour; harsh unpredictable childhood environments; sensation-seeking; impulsivity; self-control; stress). This study used a crowdsourced community sample (n = 469) recruited from Amazon Mechanical Turk. Bivariate analyses showed that risk factors and some HEXACO traits (especially honesty-humility) were associated with problem gambling issues. Among protective factors, only trait mindfulness showed a bivariate association with problem gambling issues. Somewhat surprisingly, regression analyses revealed that protective factors did not explain variance in problem gambling beyond HEXACO traits and risk factors. However, in exploratory analyses, mindfulness and self-efficacy – both modifiable protective factors – moderated the relationship between high-frequency gambling (a key proximate antecedent of problem gambling) and problem gambling tendencies. These results suggest mindfulness and self-efficacy may serve as ‘buffers’ against the development of problem gambling issues and may be promising targets for clinical interventions.