The Markov Process as a Model of Migration Based on the Example of the Movement of Banknotes

This paper presents a way of using the Markov chain model for the analysis of migration based on the example of banknote migration between regions in Poland. We have presented the application of the methodology for estimating one-step transition probabilities for the Markov chain based on macro-data gathered during the project conducted in the National Bank of Poland (NBP) in the period of December 2015–2018. We have shown the usefulness of state-aggregated Markov chain not only as a model of banknote migration but as migration in general. The banknotes are considered here as goods, so their migration is strictly related to, inter alia, the movement of people (commuting to work, business trips, etc.).Thus, the gravity-like properties of cash migration pointed to the gravity model as one of the most pervasive empirical models in regional science. Transition probability of the Markov chain expressing the attractive force between regions allows for estimating the gravity model for the identification of relevant reasons of note and, consequently, people migration.

Assess Digital Maturity to Set Digital Transformation Strategy in Oil and Gas

This paper presents a structured methodology for an oil company to embark on a digital transformation. It was implemented in several JVs with a NOC that includes three producing blocks with dozens of mature fields. The methodology has several key unique strengths: One is the ability to isolate the core-money-making processes and build a digital strategy around them. This shows early gains and at the same time becomes a buy-in support for management. Another advantage is the simplicity to define the "desired" digital maturity level using direct input from the final stakeholders. This is achieved by using the process enhancement method, a SIPOC technique (Supplier, Input, Process, Output, Customer analysis). Also, an important strength is the methodology does not ignore the existing IT infrastructure, nor the field systems (i.e., SCADA) and re-uses them, as much as possible, giving enough time for a transition or an upgrade when needed. Several tools are provided in this paper that makes the methodology consistent, auditable, and strong to support the designed digital strategy to any management level with high chance of approval. The methodology is flexible enough to be run on various types of contracts, hydrocarbon phase or operational environments. As with any method, it relies on commitment from the top and base line in the organization, requiring open and honest evaluation of current inefficiencies and, equally important, resources (budget and people). In summary, a digital transformation is not a sudden leap from a company's current analog status to an instantaneous digital state of being. Rather, it is a progressive, step-by-step transition of core processes and user-centric workflows that requires careful planning and a thoughtful methodology to find the most suitable scenario for each company.

A slow road from meat dominance to more sustainable diets: an analysis of purchase preferences

Background: Achieving a sustainable and healthy diet requires increased replacement of red meat with more sustainable foods. There is a call for novel methodologies to assess the potential of different interventions and policies in enhancing the transition from the current to more sustainable choices. Objective: We aimed to characterize consumer clusters with similar preferences in protein sources, to compare the purchase prices of these foods, and to identify ongoing transitions from one protein source to another. Design: Grocery purchase data with individual attributes on 29,437 consenting loyalty card holders were analyzed over 2.3 year period. We designed a sequence analysis to group participants to clusters with similar purchase preferences over the follow-up period and to estimate transition probabilities between preferences. We studied the determinants of prevalent purchase profiles by ordinal logistic models. Results: We identified six participant profiles with similar preferences in four protein sources: red meat, poultry, fish, and plant-based foods. Red meat dominated the purchase preferences and showed the highest persistence over time. The majority (70%) of the participants demonstrated somewhat mixed purchase profiles. A step-by-step transition from red meat towards plant-based food preference seems most likely via poultry and fish. Overall, low income was not a barrier to a more sustainable purchase profile, while price may deter the purchase of fish. The most important resources in choosing more sustainable profiles were education and stage of family life. Conclusions: Societal incentives for sustainable food choices seem most crucial at transition stages of life course and for the less educated. Here we also demonstrate that grocery purchase data offer a valuable tool for monitoring the progressive transition towards a healthy and sustainable food system.

Simple models highlight differences in the walking biomechanics of young children and adults

Adults conserve metabolic energy during walking by minimizing the step-to-step transition work performed by the legs during double support and by utilizing spring-like mechanisms in their legs, but little is known as to whether children utilize these same mechanisms. To gain a better understanding, we studied how children (5-6 years) and adults modulate the mechanical and metabolic demands of walking at their preferred speed, across slow (75%), preferred (100%), and fast (125%) step frequencies. We quantified the 1) positive mass-specific work done by the trailing leg during step-to-step transitions and 2) the leg's spring-like behavior during single support. On average, children walked with a 36% greater net cost of transport (COT; J/kg/m) than adults (p=0.03), yet both groups increased their net COT at varying step frequencies. After scaling for speed, children generated ∼2-fold less trailing limb positive scaled mechanical work during the step-to-step transition (p=0.02). Unlike adults, children did not modulate their trailing limb positive work to meet the demands of walking at 75% and 125% of their preferred step frequency. In single support, young children operated their stance limb with much greater compliance than adults (k̂= 6.23 vs. 11.35; p=.023). Our observations suggest that the mechanics of walking in children 5-6 years are fundamentally distinct from the mechanics of walking in adults and may help to explain a child's higher net COT. These insights have implications for the design of assistive devices for children and suggest that children cannot be simply treated as scaled down versions of adults.

Neuromuscular Age-Related Adjustment of Gait When Moving Upwards and Downwards

Locomotor movements are accommodated to various surface conditions by means of specific locomotor adjustments. This study examined underlying age-related differences in neuromuscular control during level walking and on a positive or negative slope, and during stepping upstairs and downstairs. Ten elderly and eight young adults walked on a treadmill at two different speeds and at three different inclinations (0°, +6°, and −6°). They were also asked to ascend and descend stairs at self-selected speeds. Full body kinematics and surface electromyography of 12 lower-limb muscles were recorded. We compared the intersegmental coordination, muscle activity, and corresponding modifications of spinal motoneuronal output in young and older adults. Despite great similarity between the neuromuscular control of young and older adults, our findings highlight subtle age-related differences in all conditions, potentially reflecting systematic age-related adjustments of the neuromuscular control of locomotion across various support surfaces. The main distinctive feature of walking in older adults is a significantly wider and earlier activation of muscles innervated by the sacral segments. These changes in neuromuscular control are reflected in a reduction or lack of propulsion observed at the end of stance in older adults at different slopes, with the result of a delay in the timing of redirection of the centre-of-mass velocity and of an unanticipated step-to-step transition strategy.

A slow road from meat dominance to more sustainable diets: an analysis of purchase preferences (Preprint)

BACKGROUND Achieving a sustainable and healthy diet requires increased replacement of red meat with more sustainable foods. There is a call for novel methodologies to assess the potential of different interventions and policies in enhancing the transition from the current to more sustainable choices. OBJECTIVE We aimed to characterize consumer clusters with similar preferences in protein sources, to compare the purchase prices of these foods, and to identify ongoing transitions from one protein source to another. METHODS Grocery purchase data with individual attributes on 29,437 consenting loyalty card holders were analyzed over 2.3 year period. We designed a sequence analysis to group participants to clusters with similar purchase preferences over the follow-up period and to estimate transition probabilities between preferences. We studied the determinants of prevalent purchase profiles by ordinal logistic models. RESULTS We identified six participant profiles with similar preferences in four protein sources: red meat, poultry, fish, and plant-based foods. Red meat dominated the purchase preferences and showed the highest persistence over time. The majority (70%) of the participants demonstrated somewhat mixed purchase profiles. A step-by-step transition from red meat towards plant-based food preference seems most likely via poultry and fish. Overall, low income was not a barrier to a more sustainable purchase profile, while price may deter the purchase of fish. The most important resources in choosing more sustainable profiles were education and stage of family life. CONCLUSIONS Societal incentives for sustainable food choices seem most crucial at transition stages of life course and for the less educated. Here we also demonstrate that grocery purchase data offer a valuable tool for monitoring the progressive transition towards a healthy and sustainable food system. CLINICALTRIAL Not applicable.

Petri Net-Based Semi-Compiled Code Generation for Programmable Logic Controllers

Industrial discrete event dynamic systems (DEDSs) are commonly modeled by means of Petri nets (PNs). PNs have the capability to model behaviors such as concurrency, synchronization, and resource sharing, compared to a step transition function chart or GRAphe Fonctionnel de Commande Etape Transition (GRAFCET) which is a particular case of a PN. However, there is not an effective systematic way to implement a PN in a programmable logic controller (PLC), and so the implementation of such a controller outside a PLC in some external software that will communicate with the PLC is very common. There have been some attempts to implement PNs within a PLC, but they are dependent on how the logic of places and transitions is programmed for each application. This work proposes a novel application-independent and platform-independent PN implementation methodology. This methodology is a systematic way to implement a PN controller within industrial PLCs. A great portion of the code will be validated automatically prior to PLC implementation. Net structure and marking evolution will be checked on the basis of PN model structural analysis, and only net interpretation will be manually coded and error-prone. Thus, this methodology represents a systematic and semi-compiled PN implementation method. A use case supported by a digital twin (DT) is shown where the automated solution required by a manufacturing system is carried out and executed in two different devices for portability testing, and the scan cycle periods are compared for both approaches.

Stochastic Response of a Vibro-Impact System via a New Impact-to-Impact Mapping

In this paper, a new impact-to-impact mapping is constructed to investigate the stochastic response of a nonautonomous vibro-impact system. The significant feature lies in the choice of Poincaré section, which consists of impact surface and codimensional time. Firstly, we construct a new impact-to-impact mapping to calculate the one-step transition probability matrix from a given impact to the next. Then, according to the matrix, we can investigate the stochastic responses of a nonautonomous vibro-impact system at the impact instants. The new impact-to-impact mapping is smooth and it effectively overcomes the nondifferentiability caused by the impact. A linear and a nonlinear nonautonomous vibro-impact systems are analyzed to verify the effectiveness of the strategy. The stochastic P-bifurcations induced by the noise intensity and system parameters are studied at the impact instants. Compared with Monte Carlo simulations, the new impact-to-impact strategy is accurate for nonautonomous vibro-impact systems with arbitrary restitution coefficients.