Early Warning Indicators for Challenges in Underground Coal Storage

Early warning or leading indicators are discussed for unexpected incidences in case of large‐scale underground coal storage at a power plant. The experience is compared with above‐ground stockpiles for which established procedures are available but where access for prevention and mitigation are much easier. It is suggested that while the explicit organization, procedures, and the general safety systems aim to provide the targeted levels of performance for the storage, representing new technology without much precedence elsewhere in the world, the extensive experience and tacit knowledge from above‐ground open and closed storage systems can help to prepare for and to prevent unwanted incidents in the underground storage. This kind of experience has been also found useful for developing the leading or early warning indicators for underground storage. Examples are given on observed autoignition and freezing of coal in the storage silos, and on occupational hazards. Selection of the leading indicators needs to consider the specific features of the unique underground facility.     

Effects of targets and aggregation on the propagation of error in mortality forecasts

Official forecasts of mortality depend on assumptions about target values for the future rates of decline in mortality rates. Smooth functions connect the jump‐off (base‐year) mortality to the level implied by the targets. Three alternative sets of targets are assumed, leading to high, middle, and low forecasts. We show that this process can be closely modeled using simple linear statistical models. These explicit models allow us to analyze the error structure of the forecasts. We show that the current assumption of perfect correlation between errors in different ages, at different forecast years, and for different causes of death, is erroneous. An alternative correlation structure is suggested, and we show how its parameters can be estimated from the past data.

The effect of the level of aggregation on the accuracy of mortality forecasts is considered. It is not clear whether or not age‐ and cause‐specific analyses have been more accurate in the past than analyses based on age‐specific mortality alone would have been. The major contribution of forecasting mortality by cause appears to have been in allowing for easier incorporation of expert opinion rather than in making the. data analysis more accurate or the statistical models less biased.     

Child protection in China: Changing policies and reactions from the field of social work

This article offers a general review of the development of national policies on child protection in China. It offers an in‐depth analysis of related legislation enacted between 2010 and 2015 that have had an impact on child protection and related historical, cultural and legal issues. Furthermore, in the study we examined the emerging role of social work in preventing and responding to child abuse and neglect in China. Major findings of the research include: (i) policies concerning child protection have been highly influenced by Confucianism and its perspective of the child as family property; (ii) child protection regulations on accident reporting, custody transfer, and surrogate care are gradually being refined and improved, although the legal system for child protection is still incomplete and needs further substantiation; and (iii) the involvement of non‐governmental organisations (NGOs) and social workers has enhanced the child protection system. Key Practitioner Message: ? Policies concerning child protection have been subject to an immense impact by Confucianism, placing strong responsibility on family members in providing childcare although the child is viewed as part of the family's property; ? After 1949, the newly founded socialist political structure began to exert a significant influence on welfare and child welfare policies. Because the Confucian perspective emphasised family and parental responsibility, government in China has traditionally not been heavily involved in policies that interfere in the internal workings of families; ? Since the shift toward an open‐door policy in 1979, child protection policies in China have begun to develop, with a child welfare network gradually spreading to cover the majority of children. Moreover, child protection is generally supported by the legal system, within which regulations on accident reporting, custody transfer and surrogate care are gradually being refined and improved. However, despite the huge progress achieved in recent years, there are significant deficits in its implementation and monitoring; ? The involvement of non‐governmental organisations (NGOs) and professional social work services has promoted a child protection system.     

Examining Gambling-Related Crime Reports in the National Finnish Police Register

The aim of this study is to examine the connection between gambling and criminal activity in the National Finnish Police Register. First, a method was created that enabled the search for gambling-related police reports in the National Finnish Police Register. The method is based on finding gambling-related police reports by using gambling-related headwords. Second, all police reports from 2011 that included any mention of gambling were read through (n = 2,233). Suspected gambling-related of crimes (n = 737) were selected from these reports. Those suspected gambling-related crimes were then described and categorized into six different categories: suspected online-related crimes; suspected crimes that were related to lifestyle-gaming; suspected crimes that involved a gambler as a victim of a crime; criminal activity related to problem gambling; casino-connected crimes, and intimate partnership violence resulting from gambling problems. This study, being the first in Finland, generated information on the connection between gambling and criminal activity from the perspective of police reports. Moreover, the study highlights methodological issues that are involved in studying police reports.     

Migration, fertility, and aging in stable populations

Fertility is below replacement level in all European countries, and population growth is expected to decline in the coming decades. Increasing life expectancy will accentuate concomitant aging of the population. Migration has been seen as a possible means to decelerate aging. In this article, I introduce a stable, open-population model in which cohort net migration is proportional to births. In this case, the migration-fertility trade-off can be studied with particular ease. I show that although migration can increase the growth rate, which tends to make the age distribution younger, it also has an opposite effect because of its typical age pattern. I capture the effect of the age pattern of net migration in a migration-survivor function. The effect of net migration on growth is quantified with data from 17 European countries. I show that some countries already have a level of migration that will lead to stationarity. For other countries with asymptotically declining population, migration still provides opportunities for slowing down aging of the population as a whole.     

Gaussian Scale Mixture Models for Robust Linear Multivariate Regression with Missing Data

We present an algorithm for multivariate robust Bayesian linear regression with missing data. The iterative algorithm computes an approximative posterior for the model parameters based on the variational Bayes (VB) method. Compared to the EM algorithm, the VB method has the advantage that the variance for the model parameters is also computed directly by the algorithm. We consider three families of Gaussian scale mixture models for the measurements, which include as special cases the multivariate t distribution, the multivariate Laplace distribution, and the contaminated normal model. The observations can contain missing values, assuming that the missing data mechanism can be ignored. A Matlab/Octave implementation of the algorithm is presented and applied to solve three reference examples from the literature.     

Unavoidable regularities in long words with bounded number of symbol occurrences

Traditionally in combinatorics on words one studies unavoidable regularities that appear in sufficiently long strings over a fixed size alphabet. Inspired by permutation problems originating from information security, another viewpoint is taken in this paper. We focus on combinatorial properties of long words in which the number of occurrences of any symbol is restricted by a fixed given constant. More precisely, we show that for all positive integers m and q there exists the least positive integer N(m,q) which is smaller than $m^{2^{q-1}}$ and satisfies the following: If α is a word such that

1. |alph(α)|≥N(m,q) (i.e., the cardinality of the alphabet of α is at least N(m,q)); and
2. |α| _a ≤q for each a∈alph(α) (i.e., the number of occurrences of any symbol of alph(α) in α is at most q),

then there exist a set A?alph(α) of cardinality |A|=m, an integer p∈{1,2,…,q}, and permutations σ ₁,σ ₂,…,σ _p :{1,2,…,m}→{1,2,…,m} for which $$\pi_A(\alpha)\in a_{\sigma_1(1)}^+\cdots a_{\sigma_1(m)}^+a_{\sigma _2(1)}^+\cdots a_{\sigma_2(m)}^+\cdots a_{\sigma_p(1)}^+\cdots a_{\sigma_p(m)}^+ .$$ Here A={a ₁,a ₂,…,a _m } and π _A is the projection morphism from alph(α)^? into A ^?. The second part of the paper considers information security. We give an introduction to (generalized iterated) hash functions and their security properties; finally we demonstrate how our combinatorial results are connected to constructing multicollision attacks on these functions.     

Emergence of Industries: A Review and Future Directions

This paper reviews the literature on the emergence of industries and the theoretical and methodological approaches employed. The analysis reveals that industry emergence can be depicted as a three‐stage process. In the first, initial stage, a disruption to the existing industrial order triggers the second, the co‐evolutionary stage, which includes four sub‐processes related to developments in technology, markets, activity networks and industry identity. The convergence of these sub‐processes leads to the third stage, a growth stage and the birth of a new industry. While these three stages and the four sub‐processes are well covered in the literature, the authors find that there is a lack of understanding in terms of the transitions between the stages, the interactions and interdependencies between sub‐processes and moderating factors of industry emergence. Future research can bridge these gaps by exploring the different origins and initial conditions of industries, the processes and interactions in the earliest stages of industry emergence, and the role of facilitating and managing industry emergence. This implies a shift in the research focus from the industries that have emerged to the nascent processes of emergence.     

Study Design in Causal Models

The causal assumptions, the study design and the data are the elements required for scientific inference in empirical research. The research is adequately communicated only if all of these elements and their relations are described precisely. Causal models with design describe the study design and the missing‐data mechanism together with the causal structure and allow the direct application of causal calculus in the estimation of the causal effects. The flow of the study is visualized by ordering the nodes of the causal diagram in two dimensions by their causal order and the time of the observation. Conclusions on whether a causal or observational relationship can be estimated from the collected incomplete data can be made directly from the graph. Causal models with design offer a systematic and unifying view to scientific inference and increase the clarity and speed of communication. Examples on the causal models for a case–control study, a nested case–control study, a clinical trial and a two‐stage case–cohort study are presented.     

Scenarios, Uncertainty and Conditional Forecasts of the World Population

Current official population forecasts differ little from those that Whelpton made 50 years ago either in the cohort–component methodology used or in the arguments used to motivate the assumptions. However, Whelpton produced some of the most erroneous forecasts of this century. This suggests that current forecasters should ensure that they give users an assessment of the uncertainty of their forecasts. We show how simple statistical methods can be combined with expert judgment to arrive at an overall predictive distribution for the future population. We apply the methods to a world population forecast that was made in 1994. Accepting that point forecast, we find that the probability is only about 2% that the world population in the year 2030 will be less than the low scenario of 8317 million. The probability that the world population will exceed the high scenario of 10 736 million is about 13%. Similarly, the probability is only about 51% that the high–low interval of a recent United Nations (UN) forecast will contain the true population in the year 2025. Even if we consider the UN high–low intervals as conditional on the possible future policies of its member states, they appear to have a relatively small probability of encompassing the future population.