Víctor M. Albornoz

MIP model scheduling for multi-clusters

Multi-cluster environments are composed of multiple clusters that act collaboratively, thus allowing computational problems that require more resources than those available in a single cluster to be treated. However, the degree of complexity of the scheduling process is greatly increased by the resources heterogeneity and the co-allocation process, which distributes the tasks of parallel jobs across cluster boundaries. In this paper, the authors propose a new MIP model which determines the best scheduling for all the jobs in the queue, identifying their resource allocation and its execution order to minimize the overall makespan. The results show that the proposed technique produces a highly compact scheduling of the jobs, producing better resources utilization and lower overall makespan. This makes the proposed technique especially useful for environments dealing with limited resources and large applications.

A Hierarchical Planning Scheme Based on Precision Agriculture

The process for agriculture planning starts by delineating the field into site-specific rectangular management zones to face within-field variability. We propose a bi-objective model that minimizes the number of these zones and maximizes their homogeneity with respect to a soil property. Then we use a method to assign the crops to the different plots to obtain the best profit at the end of the production cycle subject to water forecasts for the period, humidity sensors, and the chemical and physical properties of the zones within the plot. With this crop planning model we can identify the best management zones of the previous bi-objective model. Finally, we show a real-time irrigation method to decide the amount of water for each plot, at each irrigation turn, in order to maximize the total final yield. This is a critical decision in countries where water shortages are frequent. In this study we integrate these stages in a hierarchical process for the agriculture planning and empirically prove its efficiency.

Optimal routing for minimum wavelength requirements in end-to-end optical burst switching rings

A novel routing and link dimensioning optimisation method which minimises the total wavelength requirements of dynamic optical WDM rings - the most popular topology in metropolitan networks- is proposed. The method finds the solution (set of routes) of minimum cost by solving an integer linear optimisation problem. Contrary to the common belief, results show that the optimal routes found by the proposed method are not necessarily balanced and that significant wavelength savings are achieved compared to the usual balanced-load routing approach in rings. This makes the proposed method the best choice for implementation in future dynamic WDM ring networks.

An Empirical Design of a Column Generation Algorithm Applied to a Management Zone Delineation Problem

This paper develops and compares different strategies which involve algorithms for column generation for the problem solving of agricultural field partitioning into rectangular-shaped management zones, represented by an integer linear programming model. The main objective of this paper is to select an efficient alternative to solve the linear relaxation of the problem, which does not alter significantly the quality of the integer solution proposed. The paper also describes the model addressed, the solving method studied and computational results for a set of various problem sizes.

MIP Model Scheduling for BSP Parallel Applications on Multi-cluster Environments

Multi-cluster environments are composed of multiple clusters that act collaboratively, thus allowing computational problems that require more resources than those available in a single cluster to be treated. However, the degree of complexity of the scheduling process is greatly increased by the resources heterogeneity and the co-allocation process, which distributes the tasks of parallel jobs across cluster boundaries. in this paper, we use the Bulk-Synchronous Parallel model on which the jobs are composed of a fixed number of tasks that act in a collaborative manner. We propose a new MIP model which determines the best allocation for all the jobs in the queue, identifying their execution order and minimizing the overall make span. the results show that the proposed technique produces a highly compact scheduling of the jobs, achieving better resource utilization and reducing the overall make span. This makes the OAS technique especially useful for environments dealing with limited resources and large applications.

USO DE CADENAS DE MARKOV PARA LA PREDICCIÓN DE LA DINÁMICA DEL COMPORTAMIENTO DE PACIENTES EN UNA UNIDAD DE CUIDADO INTENSIVO CARDIOLÓGICA

In this paper we present a probabilistic model that contributes to the study of dynamics in the behavior and permanence of patients in a cardiovascular intensive care unit. The model corresponds to a discrete Markov Chain, that allows to predict the time that a patient remains in the system through the time, by means of certain severity of illness states and the corresponding transition probabilities between those states. The different states are based on the construction of a new score created for this study. We summarize the details of the adopted methodology and the main results reached in the application of the model.

Routing and spectrum assignment for elastic, static, and without conversion optical networks with ring topology

In this article we solve the Routing and Spectre Assignment problem for elastic, static, without wavelength conversion networks with ring topology. The problem is to find a route for each connection and assign the same portion of spectrum in each link of the route. The proposed solution minimizes the cost of the network, represented as the sum of frequency slot units used on each link. An integer programming model its used to represent the described problem. As a method of resolution we propose a solving strategy in two stages to first find the shortest path for each connection and then use the integer programming model, using only the proposed routes. The results of two types of instances are displayed and compared with the results of Shortest Path-First Fit. The proposed method achieves up to 22 % savings.

Modelo de optimización para el cálculo de la cuota de captura de langostino amarillo

This paper presents a nonlinear optimization model that use to establish an annual quota for the total allo- wable catch for managing the yellow squat lobster fishery. The proposed bioeconomic model maximizes the economic profits of the activity involved and, simultaneously, takes into account the long-term conservation of the resource by restricting catches and thereby assuring adequate biomass level in the future. The dynamic behavior of the population is incorporated through a single-specie logistic growth model. Parameters (e.g., growth rate, maximun population and ish eort) were estimated based on a sampling technique using historical biomass reports and fishing yields. The results obtained with this methodology are shown, as is their application in managing this particular fi shery in the north of Chile.

A Stackelberg Game Model between Manufacturer and Wholesaler in a Food Supply Chain.

This paper describes an application of the Stackerlberg game model for the food supply chain. Specifically, the focus of this work is on the pork industry and considers a production game. Such game includes two players, manufacturer and wholesaler, who both aim to maximize profit. The role of leader is played by the manufacturer, and follower by the wholesaler. Decisions involved in the game are the level of production, quantity to be sold by the leader, and level of purchased products by the follower at each time period. This paper presents a case study, and results show that coordination between these players is seen in cost savings and improved service level.

Short-term Production Scheduling in the Soft Drink Industry

In this study, the formulation of a mixed-integer linear programming model applied to production scheduling in the soft drink industry is addressed. The model considers the production of beverages with different flavors and formats in two synchronized production stages: preparation of syrup in storage tanks and bottling syrup in packaging lines. This model defines the order of the products at each stage of production with makespan minimization, taking into account aspects such as sequence-dependent set-up times, synchronisation between production stages, several tanks and packaging lines, capacity constraints, time constraints (deadlines). Also considered is the property of job splitting in first stage, which reduces waiting times in the packaging lines. We include the method of application in a real-world problem of a beverage bottling company. The results show that on average the application managed to improve 15.67% the company’s current solution.