Latency-aware cost optimization of the service infrastructure placement in 5G networks

Under 5G use case scenarios latency is a main challenge that must be addressed, since mission critical environments are mostly delay sensitive. To achieve this goal, the service infrastructure placement optimization is needed in the interest of minimizing the delays in the service access layer. To solve this problem, this paper mathematically models the placement problem in a Fog Computing/NFV environment as a Mixed-Integer Linear Programming problem and proposes a heuristic-based solution considering 5G mobile network requirements. As a practical result, an application was developed to achieve usability and flexibility while ensuring operational applicability of the proposed methods.Postprint (published version

Enhanced cell-based algorithm with dynamic radius in solving capacitated multi-source weber problem

Capacitated Multi-source Weber Problem (CMSWP) is a type of Location Allocation Problem (LAP) which have been extensively researched because they can be applied in a variety of contexts. Random selection of facility location in a Cell-based approach may cause infeasible or worse solutions. This is due to the unprofitable cells are not excluded and maybe selected for locating facilities. As a result, the total transportation cost increases, and solution quality is not much improved. This research finds the location of facilities in a continuous space to meet the demand of customers which minimize the total cost using Enhanced Cell-based Algorithm (ECBA). This method was derived from previous study that divides the distribution of customers into smaller cells of promising locations. The methodology consists of three phases. First, the profitable cells were constructed by applying ECBA. Second, initial facility configuration was determined using fixed and dynamic radius. Third, Alternating Transportation Problem (ATL) was applied to find a new location. The algorithm was tested on a dataset of three sizes which are 50, 654 and 1060 customers. The computational results of the algorithm prove that the results are superior in terms of total distance compared to the result of previous studies. This study provides useful knowledge to other researchers to find strategic facilities locations by considering their capacities

Mathematical Model and Stochastic Multi-Criteria Acceptability Analysis for Facility Location Problem

This paper studies a real-life public sector facility location problem. The problem fundamentally originated from the idea of downsizing the number of service centres. However, opening of new facilities is also considered in case the current facilities fail to fulfil general management demands. Two operation research methodologies are used to solve the problem and the obtained results are compared. First, a mathematical programming model is introduced to determine where the new facilities will be located, and which districts get service from which facilities, as if there were currently no existing facilities. Second, the Stochastic Multi-criteria Acceptability Analysis-TRI (SMAA-TRI) method is used to select the best suitable places for service centres among the existing facilities. It is noted that the application of mathematical programming model and SMAA-TRI integration approach on facility location problem is the first study in literature. Compression of outcomes shows that mixed integer linear programming (MILP) model tries to open facilities in districts which are favoured by SMAA-TRI solution.</span

Modeling and analysis of the generalized warehouse location problem with staircase costs

The Capacitated Warehouse Location consists of determining the number and locations of capacitated warehouses on a set of potential sites such that demands of predefined customers are met. Two typical assumptions in modeling this problem are: the capacity of warehouses is constant and that warehouses are able to truly satisfy customer demands. However, while these kinds of assumptions define a well structured problem from the mathematical modeling perspective, they are not realistic. In this thesis we relaxed such constraints based on the fact that warehouses can be built in various sizes and also warehouses can put in orders for unsatisfied customers' demand directly to the manufacturing plant with additional costs. This flexibility can lead to best decision making ability for managers and supply chain specialists to decide between higher capacity level with higher fixed and variable costs at the warehouse or direct ordering from the manufacturing plant. A new non linear integer programming formulation with staircase costs for multiple commodities in supply chain network is presented, and new method for linearizing the model is described. Computational results indicate that reasonably good solution can be obtained by the proposed linear model. Also for solving larger problems we developed a Tabu Search algorithm. The comparisons of the result between nonlinear/linear model and the Tabu Search algorithm are also presented

Network-aware Placement Optimization for Edge Computing infrastructure under 5G

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Edge Computing has grown into a key solution for coping with the stringent latency requirements of 5G scenarios. Nevertheless, the edge node placement problem raises critical concerns regarding deployment and operational expenditures (i.e., mainly due to the number of nodes to be deployed),current backhaul network capabilities, non-technical placement limitations, etc. In this paper, a novel framework called EdgeON is presented aiming at reducing the overall expenses when deploying and operating an Edge Computing (EC) network, taking into account the usage and characteristics of the in-place backhaul network. The framework implements several placement and optimization strategies targeting the heavily constrained network-aware Edge Node Placement Problem (ENPP). The results obtained by our solution are promising, achieving an average of30%less Edge Nodes (ENs) deployed and 25% higher average usage ratio when compared to other widely used heuristics. Furthermore, our strategy achieved as core offset of less than2%in comparison to the implemented Mixed Integer Linear Programming (MILP).Postprint (author's final draft

The location routing problem with facility sizing decisions

The location routing problem (LRP) integrates operational decisions on vehicle routing operations with strategic decisions on the location of the facilities or depots from which the distribution will take place. In other words, it combines the well-known vehicle routing problem (VRP) with the facility location problem (FLP). Hence, the LRP is an NP-hard combinatorial optimization problem, which justifies the use of metaheuristic approaches whenever large-scale instances need to be solved. In this paper, we explore a realistic version of the LRP in which facilities of different capacities are considered, i.e., the manager has to consider not only the location but also the size of the facilities to open. In order to tackle this optimization problem, three mixed-integer linear formulations are proposed and compared. As expected, they have been proved to be cost- and time- inefficient. Hence, a biased-randomized iterated local search algorithm is proposed. Classical instances for the LRP with homogeneous facilities are naturally extended to test the performance of our approach.Peer ReviewedPostprint (published version

The Case of Medicine Supply in Aveiro, Portugal

The evolution of the urban environment has changed significantly in the last 50 years, and we see considerable investments in urban logistics in order to make urban processes more efficient. This investigation intends to study the situation of urban logistics with the objective to study the current state of this system and analyze what lies ahead in the near future. The unmanned aerial vehicle (UAV) has been under investigation in the world of logistics, having been pointed has the next logistic technology. For that reason, we set as an objective, analyze the working process of this aircraft, its capabilities, and its limitations. Based on this information, we intend to implement a scenario of deliveries in an urban environment. This scenario will be in the city of Aveiro and consists on the delivery of medicines into pharmacies located in an urban environment. With this study, we pretend to find the best current and future solution to operate in an urban environment. The study is divided into several studies, starting with an analysis of the literature, and then we carry out the SWOT analysis. Then we implement a delivery route to pharmacies, both for daily delivery and emergency medicines. The analysis is divided into two phases, one where the vehicles would initially start from the current logistical base and another phase, where the logistical base is proposed for a new location, that has been optimized to the delivery route to be carried out. From the various analyzes carried out, we obtain very conclusive results. For routes of significant payload and distance, the UAV is still not able to have great performances, being still preferential the use of a van. However, we verified that for emergency deliveries, the UAV from the new logistics base (L2) would have the best performance, as well as it would be a low cost of implementation. In some results, the performance was close to the van or even better, although it would not be cost effective. For that reason, we foresee a robust competition from the UAV as an emerging technology. It will soon have better capabilities and more competitive prices. The cost reduction of this type of deliveries may soon be possible with the use of UAVs.O meio urbano tem evoluído durante os últimos 50 anos, onde se verificou uma enorme aposta na logística urbana, por forma a tornar as tarefas urbanas mais eficientes e económicas. Esta investigação tem como objeto o estudo da logística urbana e tem como objetivo, aprofundar e estudar a estrutura atual dos sistemas de logística e analisar o que poderá ser o futuro próximo. Atualmente, a maior aposta tecnológica no mundo da logística é a aeronave não tripulada (UAV). Posto isto, tem-se também como objetivo analisar o funcionamento destas aeronaves, nomeadamente, as suas capacidades e limitações. Partindo de um cenário de logística urbana com recurso a UAV’s, pretendemos estudar e comparar o processo de entregas nesse mesmo meio urbano. A implementação do teatro de operações será na cidade de Aveiro e consiste na entrega de medicamentos às farmácias localizadas no meio urbano. Com este estudo tencionasse encontrar a melhor solução atual e prever uma futura que se adeque à operação apresentada. O estudo está dividido em várias partes. Primeiramente, começamos por uma análise da literatura e seguido uma análise SWOT. Por fim, no caso de estudo são implementadas várias rotas de entregas a farmácias, quer para medicamentos de entrega diária, quer de emergência. O sistema de entregas está dividido em duas fases, uma onde inicialmente a partida dos veículos seria feita na atual base de logística e outra onde o veículo parte de uma base logística proposta, que estará otimizada ao percurso de entrega que se pretende realizar. Das várias análises realizadas obtivemos resultados muito conclusivos. Para rotas de grande carga e distância, o UAV não consegue ter grandes desempenhos, sendo ainda preferencial a utilização da uma carrinha. Contudo, verificamos que para entregas de emergência, o UAV teria um melhor desempenho a partir da nova base de logística, e para além disso, o sistema de implementação seria mais barato. Numa análise futura, prevemos uma concorrência muito forte por parte do UAV, visto que em alguns resultados a performance deste é próxima ou melhor do que a carrinha. Sendo uma tecnologia emergente, em breve terá melhores capacidades e preços mais concorrentes. As reduções de custos deste tipo de entregas poderão em breve ser possíveis com a utilização de um UAV