Statistical analysis of the equivalent design rainfall

Statistical analyses of rainfall data are used for the design of sewerage systems and pump-stations, for the evaluation of the duration and the frequency of overflow in runoff detention facilities, for the determination of the critical influence on a municipal wastewater-treatment plant or for the protection of watercourses from storm-water runoff (e.g., from highways). The basic data in this calculation are the intensity and the duration of a rainstorm. Different procedures used in the analysis of Equivalent Design Rainfall (EDR) in Slovenia and abroad are described. The stochastic model used is presented in more detail because of its applicability for the determination of the probability of the occurrence of partial rainfalls of higher frequencies and the determination of the lower limit of rainfall evaluation. Computation procedures and the results of the evaluation of rainfall data according to the stochastic model are presented for Ljubljana

Migration Flows through the Lens of Human Resource Ageing

Background: Ageing and shrinking of the European population influence the shrinking of central places and the hinterland of cities in a spatial structure. Migration also influences the shrinking or growing of spatial units. Various factors influence migration and, thus, spatial units\u27 demographic, social and economic stability. The age structure of citizens in a spatial unit may change not only due to population ageing but also because these factors influence the migration flows of different cohorts differently, which has not been studied so far. Objectives: We used data on internal migration between Slovenian municipalities in 2018 and 2019 to develop a cohort-based spatial interaction model to estimate future inter-municipal migration. Approach: In a spatial interaction model, we analyzed differences in the attractiveness and stickiness of municipalities for different cohorts, focusing on those over 65 who may wish to prolong their working status. We also tried to answer the question of how to mitigate shrinkage processes in spatial units by investigating the potential to contribute to the social value of communities. Results: The study\u27s results show that the 65+ cohorts do not have the same preferences regarding the attractiveness and stickiness factors as younger migrants. Conclusions: The results of our study could contribute to better decisions at the national, regional, and/or local level when designing strategies for regional, urban, and/or rural development, exploring the best solutions for long-term care, and investing in appropriate networks, or considering the revitalization of rural municipalities

Regions for Servicing Old People: Case study of Slovenia

Background: Aging is one of the most serious problems that most developed countries are facing in the 21st century. In the European Union, Member States are responsible for the planning, funding and administration of health care and social protection systems. Local authorities and state governments should undertake research toward developing an appropriate array of community-based care services for old people. Objectives: This study analyses the regions of Slovenia for servicing old people in the 2000–2010 time horizon. Methods/Approach: Sets of functional regions were modelled for each year in the analysed period using the Intramax method. Functional regions were evaluated based on the attractiveness of central places for labour commuters and the propensity to commute between regions. Results: The results show that in addition to the nominally declared regional centres of Slovenia, there are also some other local centres that should be potentially included in the functional areas for servicing old people. Conclusions: The results suggest that the regionalization into seven functional regions is the most convenient for servicing old people in the region. Furthermore, some additional functional regions at a lower level are suggested

DECISION MAKING IN COMPETITIVENESS OF REGIONS

ESPON ATTREG project aims to investigate the motivation and behaviour of migration flows and daily commuting of students, tourists, aging population migrating to their secondary homes, students and other “part time” commuters – but especially behaviour of human resources in gross migrations and daily commuting – between regions. One of the key elements of the cohesion policy of the European Commission is the contribution of the development of new transport infrastructure to regional economic development. Extensive spending has taken place under ERDF, Cohesion Fund and ISPA to reduce disparities among regions. One of the prominent initiatives in the European Union in this respect is the development of the Trans-European transport networks (TEN-T), where also investments in Slovenian networks took place among priority list, which is based on the accessibility index value. In the case study of Slovenia decision support system is suggested for better forecasting the results of investments

Supply Chain Risk of Obsolescence at Simultaneous Robust Perturbations

The earlier planning methods of supply chains (SC) in the skeleton of the extended material requirements planning (EMRP), where the time horizon of the reverse Laplace is infinite, were not convenient to estimate the impact of the technical obsolescence of the product or technology involved, which has economic, environmental, and social consequences. Therefore, the perturbations of timing are presented until the possible obsolescence, with parallel execution of the network simulation model (NSM) to evaluate the impact of the finite lifespan on the value of the chain. The EMRP, as well as the NSM, are based on the skeleton of the material requirements planning model, where delays and their perturbations are presented transparently. Contrary to the previous studies of the net present value (NPV) in the EMRP skeleton, where the infinite horizon is assumed, the impact of shortening the horizon of activities is shown here, in order to also evaluate the risk of financing investments in the SC with a shorter lifespan of products or technology. Owing to the simultaneous appearances of the stochastic variables, the parallel execution and exchanging of data, using NSM is advised. The procedures for estimation of correction factors of the NPV and their values are given.This research was partly funded by the Slovenian Research Agency, grant P5-0364 and J6-9396, and partly by the University of Padua

APPLICATION OF THE EXTENDED MRP THEORY TO A BABY FOOD COMPANY

Actual markets require companies to think about new ways to improve their business or to get additional advantages from their existing competences. Such improvements should not be limited to optimisation of individual activity cells but should be the result of broader analyses. Companies should consider their whole supply chains and make deep observation of dependencies between individual activity cells. Material requirements planning (MRP) Theory has proved to be a successful tool for describing and evaluating multistage, multilevel production systems with the use of Net Present Value (NPV) calculation. Recently, this theory has been extended in a way that it also deals with other vital parts of global supply chains, such as distribution, consumption and the reverse logistics. We call this approach the Extended MRP Theory (EMRP Theory). This paper shows how EMRP Theory can be used in analysing business processes for a Spanish company dedicated to baby food production

Net present value evaluation of energy production and consumption in repeated reverse logistics

The paper is based on Grubbström’s MRP theory previously used in analysis of production processes “under one roof ”. This theory has recently been extended to model global supply chains by Bogataj and Grubbström, both scientists from the MEDIFAS faculty. Every production cycle is followed by distribution, consumption and recycling activities. In broad supply chains, transportation costs between pairs of activity cells have a significant impact on the overall net present value of the system. Possible flows inside or between subsystems can all be described with input-output matrices H and G. Recently published papers of the above mentioned authors describe the presentation of supply chains in a generalized form. Generalized input and output matrices H( )s ( and ( )s ( G hold technical coefficients and lead times. Lead times are split into 2 parts: production and transportation. As presented in the publication of R. W. Grubbström, L. Bogataj and M. Bogataj, and further research of these authors, the results of recycling activities in the extended MRP model are the recovered and the waste items, but in their model the recycling of the items is not repeated. Recovered items could be reused several times in future production cycles, reducing the need to purchase new items on the market as considered here. The waste items must be disposed of, requiring environmental taxes which vary among regions, depending on local environmental policy. If recovered, items must be delivered from the recycling facility back to production, and waste items must be sent to landfills. This process requires an expenditure of human resources, and energy at each activity cell plays an important role. In this article we show how the location of recycling facilities, the prices and quantity of energy needed and the environmental taxes can drastically influence the net present value for the entire system. We also present the method for evaluating cases where energy can be recovered during recycling or decomposition processes at landfills. It is also assumed that energy recovery can be stimulated with subsidized purchase prices, but generally, lower quality energy can be expected as an output of these processes. This paper introduces generalized input and output energy matrices, which describe these energy flows and their impact on environmental sustainability through the net present value of the system, which is the novelty in the extended MRP theory. First published online: 17 Sep 201

EVALUATING FUNCTIONAL REGIONS

In the paper, we suggest an approach to evaluate the number and composition of functional regions. Suggested approach is based on basic characteristics of functional regions, that are (1) more intensive intra-regional than the inter-regional interactions and (2) internal social and economic heterogeneity. Those characteristics are measured by factors estimated in spatial interaction model. The approach to evaluate functional regions was applied to Slovenia for three time periods

Closed Loop Supply Chain (CLSC): economics, modelling, management and control

This article summarizes the papers published in the special issue entitled “Closed Loop Supply Chain (CLSC): Economics, Modelling, Management and Control” in the International Journal of Production Economics. A total of 24 papers, covering an extensive range of topics in the Closed Loop Supply Chain research area, have been included in this special issue. This special issue received a wide and diverse geographical contribution with authors from 16 countries located in 4 continents including America, Asia, Europe, and Africa. Initially, the special issue received 71 research paper submissions and the final selection of 24 papers, which were recommended by at least two reviewers, provide a basis for new research directions in the domain of reverse logistics and Closed Loop Supply Chain management