The determination of capacity expansion programmes with economies of scale

For many production processes there are economies of scale with plant investments and certain operating costs. With long-term increases in demand this affects the timing and sizing of capacity expansion projects. This paper is concerned with the development of optimal expansion programmes. It applies dynamic programming models to minimize the present value of capita! costs, operating expenses and capacity shortage losses.

The paper considers homogeneous production capacity and heterogeneous plant where constituent units have different economies of scale arid working lives. The algorithm is applied to the analysis of an expansion programme for an integrated pulp mill.

The planning implications of such models are considered. Using sensitivity analysis, a number of variables such as discount rates, inflation effects and demand patterns are related to the economy scale factor. This indicates that the optimum capacity expansion schedule is sensitive to discount and inflation rates.     

RMS capacity utilisation: product family and supply chain

The paper contributes to development of RMS through linkage with external stakeholders such as customers and suppliers of parts/raw materials to handle demand fluctuations that necessitate information sharing across the supply chain tiers. RMS is developed as an integrated supply chain hub for adjusting production capacity using a hybrid methodology of decision trees and Markov analysis. The proposed Markov Chain model contributes to evaluate and monitor system reconfigurations required due to changes of product families with consideration of the product life cycles. The simulation findings indicate that system productivity and financial performance in terms of the profit contribution of product-process allocation will vary over configuration stages. The capacity of an RMS with limited product families and/or limited model variants becomes gradually inoperative whilst approaching upcoming configuration stages due to the end of product life cycles. As a result, reconfiguration preparation is suggested quite before ending life cycle of an existing product in process, for switching from a product family to a new/another product family in the production range, subject to its present demand. The proposed model is illustrated through a simplified case study with given product families and transition probabilities.     

Measuring technological diversification: identifying the effects of patent scale and patent scope

Although technological diversification is an important strategic decision for both large and small firms alike, the conventional method of measuring such diversification may well introduce significant scale bias against small- and medium-sized firms. We examine this issue in this study using a sample of 73 Taiwanese integrated-circuit (IC) design firms covering the period from 1995 to 2007 and conclude that the conventional measure of technological diversification reflects the spread or distribution amongst technology classes of a company’s current technology portfolio, and does not capture the incremental expansion in technological scope, or the ‘dynamic act of diversification’, as reflected in our alternative scope measure. Our results suggest clear constraints on the applications made under the conventional index, particularly for firms with small patent scale.     

Manufacturing‐integrated product solutions: Design support between product function and manufacturing processes

With the help of new design tools, manufacturing‐integrated solutions can be generated that concurrently consider function and process. Based on the design pattern matrix, solution elements can be developed that realize the product function by systematically utilizing manufacturing‐induced properties. The developed manufacturing‐integrated product solutions are refined using computer‐aided methods (feature‐based modeling and information modeling). A product embodiment is generated that is specifically tailored to the chosen manufacturing technology. An integrated information model allows the introduced tools to be used throughout the entire development process. The example of a linear flow split snap‐fit fastening illustrates how the tools beneficially interact and realize manufacturing potential, resulting in an innovative product design.     

Achieving yield confidence in a flow shop with single rework station via capacity expansion and process improvement

This paper provides an improvement strategy for a flow shop with single rework station by modeling the flow shop as a capacitated manufacturing network (CMN) to achieve the required yield confidence utilizing a confidence-based analysis. We define the yield confidence as a performance indicator to evaluate the probability that a specified level of demand will be satisfied. Specifically, this paper considers capacity expansion and process improvement issues. First, a model is proposed to represent the CMN and to characterize the probability that a unit of material is successfully transformed into a final product. This model further identifies the required amount of (ideal) input to satisfy the customer demand and to achieve the desired yield confidence. In particular, this ideal input can be seen as the least wasteful input for the CMN. Capacity expansion and process improvement are considered when the current capacity of the CMN is insufficient to process the ideal input. The approach identifies the target output ratios of stations needed to achieve a process improvement goal. Two benchmark examples are provided to demonstrate the model building, capacity expansion, and process improvement steps.     

A comparative study between a small time scale model and the two driving force model for fatigue analysis

A comparative study is performed to demonstrate the difference and similarity between the two driving force approach and a small time scale model under both constant and variable amplitude loading. The small time scale model is different from most existing fatigue analysis methodologies and is based on the instantaneous crack growth kinetics within one cycle. The two driving force approach is cycle-based and uses two driving force parameters to describe crack growth rate per cycle under constant amplitude loadings. A simple modified two driving force approach is proposed based on the concept of forward and reverse plastic zone interaction and is used to calculate the fatigue crack growth under general variable amplitude loadings. Extensive experimental data for various metallic materials are used to validate the two driving force model and the small time scale model.     

Ultimate fracture capacity of pressurised pipes with defects - Comparisons of large scale testing and numerical simulations

In this paper results from large scale 4-point bending tests of pipe-segments are compared with numerical analyses using LINK_pipe. The experiments were carried out as a part of the joint industry project Fracture Control - Offshore Pipelines. The comparisons between large scale testing of pipelines and numerical analyses also address the effect of biaxial loading on the strain capacity. The defect is positioned on the tension side of the pipe when applying the load. A parametric study on changing the nominal wall thickness of the pipe is carried out. Due to variation in the yield stress, a parametric study to see the effect of this variation was also performed. The results demonstrate that ductile crack growth and biaxial loading are important elements in fracture assessment procedures for pipelines.     

Technology solutions for product lifecycle knowledge management: framework and a case study

Information technology has promoted our society gradually into knowledge economy from product economy. Value creation requires more and more knowledge and information to support enterprise activities. Knowledge management (KM) as an activity has already existed, and will make the organisation and individual have stronger competition strength, and make better decisions. In order to respond to the industrial trend towards knowledge management, this paper investigates and proposes a framework for product lifecycle knowledge management that utilises product maintenance data across the lifecycle of the product. A case presented in this paper is a maintenance knowledge service system to prove the framework method.     

Optimisation of online retailer pricing and carrier capacity expansion during low-price promotions with coordination of a decentralised supply chain

In recent years, many online retailers in China set low prices on 11 November, which stimulates huge delivery demand and results in many problems although carriers make an effort to increase their delivery capacities temporarily. To circumvent this difficulty, we consider a supply chain consisting of an online retailer, who can set price to influence the demand, and a capacitated carrier, whose capacity can be expanded at a high cost. We derive the optimal decisions in the centralised and decentralised decision systems, and compare the performances of the two systems. We find that the optimal decisions, and which system has lower price, larger capacity increment, and more late delivered goods depends on the model parameters (the market scale, the late delivery costs, the capacity expansion cost, the delivery fee, and the demand uncertainty). Specially, we show that, contrary to the traditional channel, the online retailer in the decentralised system may set lower price and the carrier has less incentive to expand capacity in the decentralised system in some situations, which underlines the need for coordination. In addition, we propose coordination contracts to improve the overall performance of the supply chain under deterministic and random demands.     

The impact of product substitution and retail capacity on the timing and depth of price promotions: theory and evidence

We investigate the impact of store capacity and extent of inter-product substitution in a retailer’s assortment on the optimal timing and depth of price promotions. We develop a stylised model of a monopolistic retailer selling two substitutable products over time, where demand for each product in each period is a function of the prices of both products in that and earlier periods as well as the degree of substitution between the two periods. We present closed-form solutions to limiting cases of the model, and observe the following: When retailers optimise profits, (1) price promotions are relatively deeper in both absolute and relative terms at higher capacity stores than at low capacity stores, (2) price promotions for more expensive products are relatively deeper (shallower) in both absolute and relative terms than price promotions for cheaper products if the degree of substitution is low (high) and (3) the products are sequentially promoted if the degree of substitution is low, and simultaneously promoted if the degree of substitution is high. To confirm that these insights from a simple stylised two-product model are relevant in practice, we survey price promotions within the shampoo and detergent assortments of four mass-market retailers, and observe behaviour corresponding to the results from our stylised model.     

Unilateral contact with adhesion and friction between two hyperelastic bodies

In the present paper, we consider a thermodynamic model using the contact kinematics developed by A. Curnier, Q.C. He and J.J. Téléga [C. R. Acad. Sci. Paris Sér. II 314 (1992) 1] involving unilateral contact, adhesion and Coulomb friction between two homogeneous, isotropic and hyperelastic bodies. Adhesion is described by an internal state variable β introduced by M. Frémond [C. R. Acad. Sci. Paris Sér. II 295 (1982) 913; J. Theor. Appl. Mech. 6 (1987) 383]. Taking the case of contact between a hyperelastic solid and a plane support, we formulate the associated boundary value problem as a minimization problem when no friction is involved. When the intensity of the adhesion obeys a ‘static' law, we obtain an existence result for this problem.     

非均匀的纳米晶硅(nc-Si)薄膜的横向热伏效应

采用磁控溅射技术在石英衬底上沉积1层200nm厚的非晶硅(a-Si)薄膜,并用真空热蒸发在其上沉积两个横向接触的厚度不同(分别为50和100nm)的Al膜.将已沉积好的薄膜在N2气氛中600℃下退火45min,得到两个横向接触的具有不同晶化程度的纳米晶硅(nc-si)薄膜.利用X射线衍射(XRD)、Raman光谱、扫描电子显微镜(SEM)和透射电子显微镜(TEM)研究了所制备样品的结构特性.由较厚Al膜诱导的nc-Si薄膜的Si晶粒平均尺寸为25nm,晶化率为56%;由较薄Al膜诱导的nc-Si薄膜的Si晶粒平均尺寸为15nm,晶化率为23%.实验发现在没有温度梯度的情况下,这两个不同晶化程度的nc-Si薄膜之间具有横向热伏效应.温度为273K时,其开路电压为1.2mV,短路电流为40nA;当温度达到373K时,其开路电压达到25mV,短路电流达到1.171μA.     

Modelling and resolving the joint problem of capacity expansion and allocation with multiple resources and a limited budget in the semiconductor testing industry

In the semiconductor testing process, many resources such as testers, handlers, loadboards and toolings are required to be ready simultaneously so that testing tasks can be conducted. A limited budget under depressed economy enhances the need for exploring better solutions of testing capacity expansion and allocation. However, to maximize profit as planning with multiple resources is very challenging. This study focused on the issues pertaining to the decisions of (1) the type and number of testers that should be invested to deal with forthcoming orders at a semiconductor testing facility under a constrained budget and (2) the allocation of tester capacity for the orders so as to maximize company profit with limited, multiple resources. Owing to the high computational complexity of the problem, the study developed a genetic algorithm to resolve the two issues simultaneously. A mathematical model was developed to formalize the problem and serve as a benchmark for comparison with the proposed algorithm that attacked the same problem more efficiently. Taguchi experimental design was employed to find the most appropriate parameters for the proposed genetic algorithm under a variety of budget set-up. Experimental results indicated that the proposed algorithm was robust enough to budget plans, and its performance approximated closely with that of the mathematical model.     

New achievable rate and a certain capacity result for a stochastic two relay network with no interference

Gastpar and Vetterli named the ad hoc networks with one randomly selected source-destination pair as relay networks, and they suggested using arbitrary network coding in order to increase the overall efficiency. Here, the relay network is investigated with two relays, no interference and a new achievable rate is obtained using a new network coding (decode-and-broadcast). The obtained achievable rate (i) gives the lower bound for general relay channel, obtained by Cover and El Gamal, but with a slight difference owing to no interference assumption at the receiver, (ii) includes the one relay rates of a two-level relay channel studied by Gupta and Kumar using point-to-point coding, (iii) includes the rates of two-relay Aref network and other special two-relay networks, (iv) meets the max-flow min-cut upper bound under certain additional assumptions resulting in certain capacity theorems that include the related previous capacities, (v) is validated by its consistency with previous results relevant to special cases of broadcast channels.     

The organizational choice between evolutionary and revolutionary capability regimes: theory and evidence from European air transport

Resource- and capability-based models of firm strategy gainin analytical power by incorporating some of the organizationaltrade-offs that firms face in choosing between alternative capabilitybuilding strategies. Based on the well-documented trade-offbetween flexibility and commitment inherent in social systems,this paper argues that firms must choose between evolutionaryand revolutionary 'capability regimes'. Empirical evidence drawnfrom the race of European airlines to develop critical revenuemanagement capabilities is cited to illustrate the theory andpractical relevance of capability regimes.     

Communications and cohesion: a comparison between two command and control paradigms

This article negotiates a path between the ecological validity of field trials, the precision of mathematical modelling and the formality of lab-based experimentation. It does this by taking a longitudinal approach to comparing two types of command and control organisations. The object of the study was to use social network and simple time series analysis to test the assumption that organisational design factors can lead to systematic changes in the quantity, structure and type of communication. Further that these changes lead to corresponding improvements in team cohesion over time. The longitudinal design enables novice teams to become expert in their task, for critical task variables to be preserved and controlled, and for effects to emerge over time. It is apparent that contemporary advances in command and control architectures may not be merely technically effective (in terms of enhanced communications) but also jointly optimised (in terms of greater team cohesion).     

Subcontracting with availability guarantees: production control and capacity decisions

We present a simplified model of a system with a producer, a subcontractor and a random demand. The demand level alternates between a high level and a low level with exponential switching times. The producer does not have enough capacity to meet the high demand. Therefore, it either produces to stock in advance or uses a subcontractor to receive additional capacity when it needs. The subcontractor serves a number of manufacturers and guarantees a long-term availability that is defined as the long-term probability that the subcontractor will be available when it is requested, to each manufacturer. Therefore, a manufacturer may not receive the requested capacity from the subcontractor immediately and waits until the subcontractor becomes available. The times that the subcontractor is available and not available are also exponential random variables. The producer uses a threshold-type policy that depends on the state of the inventory/backlog to decide how much to produce and how much to request from the subcontractor. This system is modeled analytically based on a stochastic flow rate control problem with continuous flow and discrete states in a Markovian setting. A numerical analysis of the model is used to analyze the effects of guaranteed availability on the manufacturer's and subcontractor's performances. Extensions to the producer's and subcontractor's capacity decisions and the subcontractor's pricing decisions are also discussed.     

Study of capillary interaction between two grains: a new experimental device with suction control

We investigated the behavior of a water liquid bridge formed between two grains. We mainly focused on tensile tests with suction control (capillary pressure). Theoretical and experimental studies are compared. A new experimental device involving suction control of the liquid bridge was developed specifically for this kind of test. Most of the liquid bridge variables and characteristics were measured by image analysis (gorge radius, volume, contact angles, filling angles). Capillary force was measured by differential weighting. Experimental conditions allows us to avoid viscous effects. Our experimental results were close to Young-Laplace equation solutions. The “gorge method”, commonly used for calculating the capillary force, was also validated by our experiments. Liquid bridge rupture was studied and a new rupture criterion is proposed. This criterion depends on the grain radius, contact angle, surface tension and suction and was in agreement with the experimental results.