Allocation Of Components Research Articles

Optimization of Industrial-Scale Assemble-to-Order Systems

Using a novel stochastic programming (SP) formulation, we develop an algorithm for inventory control in industrial-size assemble-to-order (ATO) systems that has unparalleled efficiency and scalability. Applying our algorithm to several numerical examples, we generate new insights regarding the control and optimization of these systems. We consider a continuous time model, seeking base-stock levels for components that minimize the sum of holding costs and product-specific backorder costs. Our initial focus is on first-come, first-served (FCFS) allocation of components to products; for this setting our algorithm quickly computes solutions for which the asymptotic optimality gap with the optimal FCFS base-stock policy is less than 1%. We then turn to two related questions: How do common heuristics used in practice compare to our performance, and how costly is the FCFS assumption? For the first question, we investigate the effectiveness of ignoring simultaneous stock-outs (ISS), a heuristic that has been used by companies such as IBM and Dell. Our experiments indicate that ISS performance, when compared to the optimal FCFS base-stock policy, improves as the average newsvendor (NV) fractiles increase but suffers under lead-time demand correlations. For the second question, we develop an efficiently computable upper bound on the benefit of optimal allocation over FCFS. We find that for many large ATO systems, FCFS performs surprisingly well and that its performance improves with decreasing NV fractile asymmetry among products and, again, with increasing average NV fractiles. We also investigate simple no-holdback allocation policies and find that they tend to outperform the best FCFS policies.

Simulation of Allocation of Reliability in Component based System

The reliability allocation and minimum cost of component in a system can be used to solve the allocation problems in components based systems as well as applicable to modular systems. A method is simulated for allocating reliability to each component of a system with a view to minimizing the system cost on specific reliability. There is a need for component developer and users to make these data available to reliability estimator so that the derived results are usefully applied to practical systems. The simulation to show near optimal solution to the problem of selecting the component and comprising the software can be obtained with minimum cost. We simulate different sizes of components and their reliability with minimum cost in a system. Finally we give the importance of how to select reliability and cost of each component in Component-based software.

Response of biomass allocation patterns to thinning in Pinus halepensis differs under dry and semiarid Mediterranean climates

To implement adaptive management in post-fire-regenerated Aleppo pine forests, we developed specific biomass equations in two early-thinned climatically contrasting stands. We found thinning enlarged biomass components, although climate primarily constrained biomass accumulation and biomass allocation. The increase in burnt surface by wildfires in the Mediterranean Basin has triggered the proliferation of large unmanaged forested areas, particularly Aleppo pine stands in drier and lower altitudinal areas. These young naturally regenerated stands require specific biomass models for accurate carbon stock quantification. The aim of this study is to analyse the effects of climate (dry vs. semiarid), age and forest management (early thinning) on biomass accumulation and biomass allocation of young Pinus halepensis components: stem, crown (crown wood, needles and cones) and roots. We sampled 251 individual Aleppo pine trees across an age sequence of 5–16 years old to develop component biomass equations. We observed that biomass allocation differed with climate, age and tree density. The crown was the largest biomass fraction, followed by root fraction and stem fraction. At the most limiting site (semiarid climate), we found major reproductive efforts, which may be shaped by adaptive traits to recurrent fires or recurrent drought episodes. Climate was the first limiting factor to constrain biomass accumulation and biomass allocation. Thinning played a key role in promoting positive effects on biomass components at both sites, which were enlarged under less stressful site conditions (dry climate). These results may help managers understand how altering stand density promotes more resilient forests.

Стратегії нарощування інноваційного потенціалу підприємств харчової промисловості

The purpose of the article is caused by the emergence of new challenges for the national economy, and particularly for the agricultural sector as a result of the signing and ratification, in September 2014, of the Association Agreement EU-Ukraine. These challenges are systemic, comprehensive, extremely powerful and dangerous, so the preparation of adequate responses to them requires a transition to an innovative paradigm of businesses in the food complex in order to actively develop their innovative potential. The study used methods such as theoretical abstraction, generalization of the essential characteristics of modern paradigms of development, structural and comparative analysis and grouping, SWOT-analysis of the internal condition and environment of food-processing companies, the hierarchy of risks by source of origin, and organizing strategies for the development of structural components of the innovative potential. The authors justified theoretical and methodological foundations of economic transition to an innovative paradigm of development strategy of the food-processing industry. It is based on the assessment of the internal condition and existing potential for the whole enterprise and its components, the external economic environment and innovation and investment climate and, on this basis, the selection of innovative models of development. The strategy of increasing innovation potential of a business structure is based on the allocation of structural components and the use of different groups of sectoral strategies for development and to achieve balance. This will be an innovative and technological basis for the production of food products with innovative features (new or improved properties), and corresponding to the consumers customization by needs and tastes. The authors systematized the causes that provoked the appearance of existing or potential risks, revealed their impact on the companies' development strategy and elaborated tools whose introduction and use can neutralize and overcome the brake and centrifugal effects.

Asymptotically-optimal component allocation for Assemble-to-Order production–inventory systems

We consider component allocation in Assemble-to-Order production–inventory systems. We prove that asymptotic optimality on the diffusion scale can be achieved under a continuous-review policy. We also show that in many systems, meeting this optimality criterion requires component reservation.

Component allocation cost minimization for a multistate computer network subject to a reliability threshold using tabu search

From the perspective of business management, system supervisors are usually more concerned with the cost of a system rather than its reliability. This study determines the optimal component allocation based on the cost criterion for a computer system subject to a reliability threshold in which the computer system is represented as a network composed of a set of links and a set of vertices. The component allocation means allocating some from the set of components to the network's links, where the cost of allocating a component is counted in terms of the length. Any computer network associated with a component allocation is called a multistate computer network (MCN) because each component has multiple states with a probability distribution. Associated with a component allocation, the system reliability is the probability that the specific units of data are successfully transmitted through the MCN. An optimization algorithm, which integrates tabu search and minimal paths, is proposed to solve the problem under consideration. Several benchmark computer networks are utilized to demonstrate the computational efficiency of the proposed algorithm compared with several popular meta-heuristic algorithms.

Early Energy Estimation of Networked Embedded Systems Executing Concurrent Software Components

2 Abstract—This paper presents and evaluates a new approach of modeling energy consumption of embedded systems resulted by concurrent software components. The objective is to enable energy estimation within early phases of system development, which allows system designers to compare different allocations of software components within networked systems. The model is presented in detail and its application demo started by a case study. Additionally, an execution time estimation for software components is presented which is necessary for the energy model - but previously not available. The model was developed being applicable early in the development process, i.e. previous to any software implementation. This was realized by using only available information. The individual elements of the presented model are: energy consumption of software components themselves, energy consumption resulted by any software component, and energy consumption resulted by specific software components. The variables of the model can be estimated during early phases of system design using existing methods, expecting the execution time of software components. For that reason, a previously energy estimation technique (1) was further developed to estimate the execution time based on program flowcharts. The estimation was verified by using three commercially available benchmarks. The flowcharts of these are utilized to estimate the execution times. The comparison between estimated and measured execution time of an exemplary embedded system results in an estimation error bandwidth between -12.5 % and +6.8 %. Additionally, an algorithm is presented which enables an automated analysis of program flowcharts as part of the execution time estimation. The developed model was applied within an automotive case study which shows a theoretical energy saving potential of 36.2 %. This demonstrates the potential and relevance of modeling energy estimation within early development phases.

A note on allocation policy in two-parallel–series and two-series–parallel systems with respect to likelihood ratio order

In a recent article of Laniado and Lillo (2014), the authors obtained some comparison results on component allocation policies in two-parallel–series and two-series–parallel systems with two types of components. They proposed a conjecture that those results can be extended to likelihood ratio order. In this note, we provide an affirmative answer to their conjecture.

Optimal FCFS allocation rules for periodic‐review assemble‐to‐order systems

AbstractIn Assemble‐To‐Order (ATO) systems, situations may arise in which customer demand must be backlogged due to a shortage of some components, leaving available stock of other components unused. Such unused component stock is called remnant stock. Remnant stock is a consequence of both component ordering decisions and decisions regarding allocation of components to end‐product demand. In this article, we examine periodic‐review ATO systems under linear holding and backlogging costs with a component installation stock policy and a First‐Come‐First‐Served (FCFS) allocation policy. We show that the FCFS allocation policy decouples the problem of optimal component allocation over time into deterministic period‐by‐period optimal component allocation problems. We denote the optimal allocation of components to end‐product demand as multimatching. We solve the multi‐matching problem by an iterative algorithm. In addition, an approximation scheme for the joint replenishment and allocation optimization problem with both upper and lower bounds is proposed. Numerical experiments for base‐stock component replenishment policies show that under optimal base‐stock policies and optimal allocation, remnant stock holding costs must be taken into account. Finally, joint optimization incorporating optimal FCFS component allocation is valuable because it provides a benchmark against which heuristic methods can be compared. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 158–169, 2015

Vitamin E deficiency in last‐laid eggs limits growth of yellow‐legged gull chicks

Summary Parental phenotype and environment have cascading effects on offspring performance. Such ‘maternal’ effects are often mediated by the size and quality of the eggs in terms of maternal endogenous substances or exogenous components. Maternal effects can function to maximize parental fitness via adaptive allocation of components among sibling eggs. In birds, the often documented variation in concentration of egg dietary antioxidants or other egg compounds with laying order may thus reflect adaptive parental favouritism or maternal physiological constraints. Vitamins are found in the yolk at high concentrations and accomplish important physiological functions. Tocopherols (‘vitamin E’) have major roles in antioxidant protection, but the consequence of variation in their concentration for chick phenotype has never been experimentally investigated under a natural selection regime. In the yellow‐legged gull (Larus michahellis) free‐ranging population we studied, vitamin E concentration and egg size decline from the first to the third (last) egg. Chicks from third eggs are smaller and have lower viability compared to those from sibling eggs. Here, we tested the effect of injecting a physiological dose of vitamin E in the egg yolk on chick body size at hatching by comparison with chicks from sham‐injected eggs. As predicted, chicks from vitamin E injected third eggs were larger than chicks from control third eggs, whereas vitamin E had no effect on chicks from the other eggs. Thus, vitamin E injection disrupted the brood size hierarchy according to laying order normally found in this species. In species that adopt a brood reduction strategy, differential allocation of vitamin E to the eggs can contribute to establish a hierarchy of reproductive value among progeny members functioning to maximize parental fitness. The present results therefore have general implications for the study of the evolution of maternal effects mediated by transfer of potentially limiting maternal antioxidants to the eggs.

Operation of Hybrid Evolutionary Algorithm and Fuzzy Sets for Reliability Optimization of Engineering Systems

This article uses a specific hybrid evolutionary algorithmto solve the series parallel redundancy optimization problem which is in a fuzzy framework. Reliability optimization provides a means to help the reliability engineer achieve such a goal. Most methods of reliability optimization assume that systems have redundancy components in series and /or parallel systems and that alternative designs are available. Optimization concentrates on optimal allocation of redundancy components and optimalselection of alternative designs to meet system requirements. A fuzzy simulation-based evolutionary algorithm is then employed to solve these kinds of fuzzy programming with fuzzy goal and fuzzy constraints. Finally, numerical examples are also given.

The Influence of a Nature of Raw Materials and Applied Temperature on a Change in Make-Up and Characteristics of Fuel Shales in Baltic Area

In this paper the chemical composition and properties of briquettes from combustible slates is studied during the heat treatment, made of waste of a slate field of the Leningrad region. Formation of a large amount of ashes is the main problem connected with processing and use of combustible slates. The component structure of mineral part of slate is revealed. Change of mass of combustible slate at heat treatment in the range of temperatures 25- 950°C is defined. Reduction of mass of slates happens during five cycles about change of structure and physical and chemical properties. The analysis of allocations of gas components condensed in water solution during heat treatment showed that at increase in temperature A‘€AÂ environment decreases with 6,72 to 6,31 and P2O5, SO3 are allocated. Also in the form of a suspension at solution there are Al2O3, SiO2, CuO, ZnO, MgO. Studying of structure and physical and chemical properties of briquettes from combustible slates during heat treatment gives the chance to define the periods of devolatilization of coal and coking of samples.

A corridor method based hybrid algorithm for redundancy allocation

In this paper a hybrid algorithm for the redundancy allocation problem is presented. The problem is the allocation of redundant components within series-parallel systems. We present an algorithm that deals with the classical formulation, where at least one component per subsystem must be included in the final configuration, as well as the $$k$$k-out-of-$$n$$n formulation, in which at least $$k$$k components per subsystem must be included in the final network configuration. We propose a three-phase scheme in which the cross entropy method, the corridor method and a dynamic programming-based scheme are effectively intertwined. Computational results on well-known benchmark instances as well as on randomly generated large scale instances are presented, proving the effectiveness and robustness of the proposed algorithm.

On constrained reliability maximization using active redundancy in coherent systems with non-overlapping subsystems

The paper investigates a problem of constrained reliability maximization by allocating redundancy and proposes how to solve it for a broad group of complex coherent systems. Redundancy is an effective engineering tool to enhance system reliability to make a system fail-safe. Since adding redundancy increases the cost and complexity of a system design, it should be used wisely. The work considers an exact solution to the problem under resource constraints and finds optimal redundancy numbers. The proposed method can accommodate any number of constraints. Numerical examples have been included. A sensitivity analysis has been carried out to show how sensitive the optimal allocation of redundant components and the gain in system reliability are to the budget allocation.

Joint Pricing and Production Decisions in an Assemble-to-Order System

This paper studies coordinated pricing and production decisions in an assemble-to-order system. We first show that unlike in make-to-stock systems, a state-dependent base-stock list-price policy is optimal. The optimal state-dependent base-stock levels and list prices may increase or decrease as demand backlogs increase, whereas demand backlogs always improve the optimal expected profit. Because the problem easily becomes intractable under general system settings, we next develop a simple heuristic policy. The heuristic policy decouples inventory replenishment, pricing, and component allocation decisions in a coordinated way. We provide a sufficient condition that ensures the optimality of the heuristic policy, and present a numerical study to demonstrate its performance when the condition is not met. The numerical study also shows how the performance of the heuristic policy is affected by various market and operational conditions, and by the structure of the assemble-to-order system. By focusing on the simple W-model, we show how the heuristic pricing decisions are made in response to changes in inventory levels and various cost parameters.

Cash-Flow Sensitivities and the Allocation of Internal Cash Flow

We study how firms allocate cash flow by estimating the cash-flow sensitivities of various uses of cash flow. We decompose cash flow into a transitory and a permanent component and focus on the allocation of the transitory component, which by construction contains little information about future growth opportunities. We find that more financially constrained firms allocate more transitory cash flow to cash savings and direct less toward investment than do less constrained firms, consistent with constrained firms accumulating liquidity to buffer against future financial constraints. We also illustrate several methodological advantages of our approach over alternative methods in previous studies.

Assumptions on allocation of education information component

This article covers several issues of searching the assumptions for allocation of education information component. The main groups of such assumptions are allocated and the inherent presence of the very information component is substantiated.

Edaphic controls on ecosystem-level carbon allocation in two contrasting Amazon forests

Studies of carbon allocation in forests provide essential information for understanding spatial and temporal differences in carbon cycling that can inform models and predict possible responses to changes in climate. Amazon forests play a particularly significant role in the global carbon balance, but there are still large uncertainties regarding abiotic controls on the rates of net primary production (NPP) and the allocation of photosynthetic products to different ecosystem components. We evaluated three different aspects of stand-level carbon allocation (biomass, NPP, and its partitioning) in two amazon forests on different soils (nutrient-rich clay soils versus nutrient-poor sandy soils) but otherwise growing under similar conditions. We found differences in carbon allocation patterns between these two forests, showing that the forest on clay soil had a higher aboveground and total biomass as well as a higher aboveground NPP than the sandy forest. However, differences between the two forest types in terms of total NPP were smaller, as a consequence of different patterns in the carbon allocation of aboveground and belowground components. The proportional allocation of NPP to new foliage was relatively similar between them. Our results of aboveground biomass increments and fine-root production suggest a possible trade-off between carbon allocation to fine roots versus aboveground compartments, as opposed to the most commonly assumed trade-off between total aboveground and belowground production. Despite these differences among forests in terms of carbon allocation, the leaf area index showed only small differences, suggesting that this index is more indicative of total NPP than its aboveground or belowground components.

Orderings of coherent systems with randomized dependent components

Consider a general coherent system with independent or dependent components, and assume that the components are randomly chosen from two different stocks, with the components of the first stock having better reliability than the others. Then here we provide sufficient conditions on the component’s lifetimes and on the random numbers of components chosen from the two stocks in order to improve the reliability of the whole system according to different stochastic orders. We also discuss several examples in which such conditions are satisfied and an application to the study of the optimal random allocation of components in series and parallel systems. As a novelty, our study includes the case of coherent systems with dependent components by using basic mathematical tools (and copula theory).

Research on Component Allocation Problem for Chip Mounter Based on MATLAB

With the widespread use of the Surface Mount Technology (SMT) in electronics assembly, the efficiency of SMT production line is the most important to increase the number of products quickly, enhance the market share and competitive strength. And the key point of efficiency improvement for SMT production line is the reasonable component distribution in chip mounter. In this paper, for a widely used SMT production line, its mathematical model of component distribution for two chip mounters was established. By identifying the model constrains and processing of the mathematical model, then the mathematical model was solved through Particle Swarm Optimization (PSO) based on natural selection with MATLAB. By contrast with the MATLAB function-bintprog solving, the results by PSO based on natural selection needs less iteration and short time, and the optimal component distribution program was efficiently obtained.