Constraints Of Orders Research Articles

Dynamic community partitioning for e-commerce last mile delivery with time window constraints

Community logistics (CL) is a recently proposed delivery strategy designed to deal with e-commerce last-mile delivery scheduling by dynamically assigning vehicles to designated delivery regions partitioned into “communities”. Since optimizing vehicle routes is not mandatory in the CL spectrum, the delivery solution format and optimization process can be greatly simplified. Nevertheless, abandoning vehicle routes means vehicle arrival time at each customer specified delivery destination is unknown, resulting in the inability of handling time window constraints of e-commerce orders. To expand the application scope of CL, this study introduces community time window, an aggregation of identical or adjacent order time windows. Once the community time window for a delivery community is satisfied, all orders in this community can be received within designated time windows without determining vehicle routes. With this new concept, the application range of the CL is extended to e-commerce last mile delivery contexts where order time window constraints are considered. A dynamic community partitioning problem with the time window is presented based on the Markov decision process (MDP). An efficient heuristic solution framework based on policy function approximation is proposed to solve the MDP model. Numerical results show that the CL is very effective in dealing with the time window constraints of e-commerce orders.

A Concept on Order Quantity at Varying Cost in Variable Rate of Production Situation

The concept of EOQ is simply to tackle the management issues of inventory in various types of production systems. This is amongst the most popularly used models in the production houses for inventory. A major issue faced by stock manager is to design an effective policy for replacement, resulting outcome as lowest cost of inventory units. Traditional EOQ theory, assumes majorly two factors that is demand and per unit cost. It is assumed that demand remains constant and can be determined at any level. Secondly that per unit production cost does is not dependent on quantity of order for production. This study is based on a model for stock with multi-item and when per unit cost is dependent on demand and crashing cost of leading time is dependent on lead time. Hence, model has been formulated having constraints of orders and production cost. Unit cost of production is considered fuzzy variable. The jist problem for optimizing the annual total cost has been considered with Karush Kuhn-Tucker conditions method. Mathematical derivations and analysis have been made for one unit, along with testing done from Sensitivity analysis. Illustrations have been taken on random basis

Irrigation Systems in the South-West of Algeria Case Study of Naama Region

This study highlights the different growing systems adopted in a region steppic (wilaya of Naâma in the southwest of Algeria). This is a system: traditional classic where there is a diversity of crops (market garden and fruit), oasien is based mainly on date palm cultivation and bench that includes market gardening and fodder crops. Upstream a survey was conducted in the region of naama region to identify the potential of local cultures and existing constraints. This analysis allowed us to evaluate the varietal diversity, both herbaceous and woody, with a short vegetative cycle. Perennial that takes place in these systems. These food crops are sources of food and income for the pastoral population. Constraints of biotic and abiotic orders have been taken from different plant species. Our obejectif and our proposals for improving the production of its systems primarily concern crop protection against climatic hazards, maintain and improve soil productivity, adapt these systems to water availability, fight against pests and consolidate the socio-economic environment wich can give some recommandations to find sollution to this problem.

Cubic interactions of Maxwell-like higher spins

We study the cubic vertices for Maxwell-like higher-spins in flat and (A)dS background spaces of any dimension. Reducibility of their free spectra implies that a single cubic vertex involving any three fields subsumes a number of couplings among different particles of various spins. The resulting vertices do not involve traces of the fields and in this sense are simpler than their Fronsdal counterparts. We propose an extension of both the free theory and of its cubic deformation to a more general class of partially reducible systems, that one can obtain from the original theory upon imposing trace constraints of various orders. The key to our results is a version of the Noether procedure allowing to systematically account for the deformations of the transversality conditions to be imposed on the gauge parameters at the free level.

Design of Servo Stamping Motion Considering Constraints of Different Orders and Actuation Capability

The design of stamping motion is one of the key technologies to make the servo press performing stamping operation perfectly. An interpolation method considering constraints of different orders is proposed based on NURBS motion curve that any one or all constraints of position, velocity and acceleration can be defined at desired key points of the stamping motion in order to satisfy both accuracy and flexibility requirements. An algorithm is presented to generate the dwell section of stamping motion curve with given time span quickly. A reasonable solution is given to define the derivative magnitudes in construction of the interpolation equation to avoid stamping motion curve's distortion. A method to amend proper velocity or acceleration constraint is proposed to improve the performance of stamping motion curve. Following above discussion, a general process of servo stamping motion design is proposed and an interactive stamping motion design software is developed considering constraints from metal forming operation and actuation capability of the servomotors. Finally, the proposed stamping motion design method is demonstrated by a forming case of automobile wing workpiece.

Economic Growth and Poverty: Pro-Poor Growth? In the Republic of Congo

Using a posterior approach from 2005 to 2011, this article seeks to answer the question: does economic growth benefit the poor or not in the Republic of Congo? The study found that across the country, the index of pro-poor growth has been positive and superior to one, which is indicative of pro-poor growth, but it is pro-rich in urban areas. However, the study conceals disparities in the regions due to the constraints of informational orders. The study recommends specific policy measures to increase, specifically household surveys in twelve regions in the Republic of Congo to better understand the extent of poverty.

First- and Second-Order Optimality Conditions for Optimal Control Problems of State Constrained Integral Equations

This paper deals with optimal control problems of integral equations, with initial–final and running state constraints. The order of a running state constraint is defined in the setting of integral dynamics, and we work here with constraints of arbitrary high orders. First-order necessary conditions of optimality are given by the description of the set of Lagrange multipliers. Second-order necessary conditions are expressed by the nonnegativity of the supremum of some quadratic forms. Second-order sufficient conditions are also obtained in the case where these quadratic forms are of Legendre type.

Avaliação de modelos matemáticos para resolução de Job Shop Problem com utilização de recursos humanos especialistas em projetos

Um projeto pode ser definido como um sistema complexo que exige o emprego de recursos (recursos humanos, materiais, tecnologia, entre outros), alocados entre fins alternativos, como meio de atingir objetivos específicos, mediante a presença de restrições de diferentes ordens. O planejamento, a alocação e a priorização de recursos humanos, inclusive Recursos Humanos Especialistas (RHE) são realizados por meio do gerenciamento de projetos de forma individual. Esse tratamento pode causar disputa interna pela utilização do mesmo recurso ou até mesmo a sua subutilização. Isso pode ser mais pronunciado em ambientes de desenvolvimento de softwares devido ao alto grau de interdependência, de incerteza e de risco de cada projeto. Tal necessidade está relacionada ao chamado Job Shop Problem (JSP). Nesse contexto, o objetivo deste trabalho é avaliar modelos matemáticos de algoritmo genético e de otimização e suas contribuições para a resolução de Job Shop Problem em projetos de desenvolvimento de software com a utilização de Recursos Humanos Especialistas.

Model-based control strategies for systems with constraints of the program type

The paper presents a model-based tracking control strategy for constrained mechanical systems. Constraints we consider can be material and non-material ones referred to as program constraints. The program constraint equations represent tasks put upon system motions and they can be differential equations of orders higher than one or two, and be non-integrable. The tracking control strategy relies upon two dynamic models: a reference model, which is a dynamic model of a system with arbitrary order differential constraints and a dynamic control model. The reference model serves as a motion planner, which generates inputs to the dynamic control model. It is based upon a generalized program motion equations (GPME) method. The method enables to combine material and program constraints and merge them both into the motion equations. Lagrange’s equations with multipliers are the peculiar case of the GPME, since they can be applied to systems with constraints of first orders. Our tracking strategy referred to as a model reference program motion tracking control strategy enables tracking of any program motion predefined by the program constraints. It extends the “trajectory tracking” to the “program motion tracking”. We also demonstrate that our tracking strategy can be extended to a hybrid program motion/force tracking.

Robot motion planning in the presence of program constraints

The paper presents a method of a motion planning and tracking for constrained robots. Specifically, we are interested in program constraints, by which robot tasks can be defined. The program constraint is an input to a kind of a motion planning system, which has been based on a generalized motion equation method suitable for systems with bilateral constraints of arbitrary orders. For the program motion planned by the motion planner a closed-loop program motion tracking using a class of feedback controllers has been designed. Global tracking conditions were developed for the case of nonlinear dynamics using a modification of the computed torque method.

Routh's equations for general nonholonomic mechanical systems of variable mass

In this paper, Routh's equations for the mechanical systems of the variable mass with nonlinear nonholonomic constraints of arbitrary orders in a noninertial reference system have been deduced not from any variational principles, but from the dynamical equations of Newtonian mechanics. And then again the other forms of equations for nonholonomic systems of variable mass are obtained from Routh's equations.

Cities and environmental decline: Elites and the sewage problem in Paris from the mid‐eighteenth to the mid‐nineteenth century

This paper addresses itself to a problem that faces all cities but which was — and was seen to be — an ever more grave one for the burgeoning cities of nineteenth century Europe: environmental pollution. This problem — and in particular sewage which is the focus of the article — has as yet been little studied by historians. The paper shows, first, that in Paris in the period 1750–1850 the city was confronted by rapidly increasing quantities of sewage and that for complex cultural, class and scientific reasons Parisian elites came to perceive sewage removal as a problem that required solution and to adopt a series of strategies to do so. It shows, secondly, that the city's administration brought about changes which were of greater import than those effected under Haussmann in the 1850s and 1860s. The limits to what it could do were imposed not by short‐sightedness or parsimony, but by long‐term structural constraints of different orders, attitudinal, technological, power relationships in the capitalist city.