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This paper investigates the impact of import competition on energy efficiency among firms in China. Using a difference-in-differences approach that exploits industry- and firm-level tariff reductions following China's accession to the WTO, we examine the effects of reduced output tariffs on coal intensity, measured as coal use per output, of Chinese manufacturing firms. Our findings indicate that higher levels of import competition lead to significant reductions in coal intensity, without negatively affecting firm production levels. We also find evidence that these effects are primarily driven by multi-product firms adjusting their product mix to prioritize energy-saving options. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of separating the affiliated businesses from rail operations and the associated efficiency gain on firms' exporting decisions by rail. First, an economic model was built to analytically show that an efficiency improvement in rail operations would increase the firm's product variety but decreases the skewness of export by rail. The paper then utilized China's rail reform to separate the affiliated businesses from the rail sector in 2003 as a quasi-natural experiment and adopted the difference-in-differences (DID) method to empirically verify and quantify the analytical findings. Specifically, it is found the reform to separate the affiliated businesses significantly improved the efficiency of China's rail operations. The resultant efficiency gain then encouraged firms to export by rail, with more variety of export products and higher value. More importantly, the firm's skewness of export by rail has also been reduced. The relevant policy implications have also been provided. • This paper considers China's rail reform to separate the affiliated businesses from the rail sector in 2003. • We examine the effects of the reform on the efficiency of rail operations and the product mix of export by rail. • We find that the reform improved the efficiency of China's rail operations. • Firms' skewness of export by rail was reduced by the reform. [ABSTRACT FROM AUTHOR]

Matched firm-level balance sheet and partner- and product-level foreign trade data can be used to examine the relationship between the product mix and productivity of firms, as well as other characteristics, such as size or ownership structure (share of foreign ownership). The conclusions to be drawn on the basis of foreign trade data are supplemented by the results of analyses with production and domestic sales data. For this purpose and for the longitudinal analysis of foreign trade data, the two classification systems had to be harmonized. According to foreign trade data, the important components of the expansion of companies' export range besides productivity are the import range, the firm size, and the share of foreign ownership. Production and domestic sales data only partially support these conclusions. [ABSTRACT FROM AUTHOR]

We explore the contribution of product mix in determining firm and aggregate emission intensity. First, using detailed firm-product emission intensity data from India, we find that more efficient firms are less emission intensive, and that products with the largest sales tend to be cleaner than other products within the firm. We also find that emission intensity in India dropped significantly between 1990-2010 through reallocations across firms, while product mix played a counteracting role in increasing firm emission intensity. Next, we develop a multi-product multi-factor model with heterogeneous firms, variable markups, and monopolistic competition in which each product has a specific emission intensity. We find that pro-competitive market developments lead to an improvement in the aggregate emission intensity – through reallocations across firms – even though firms can become dirtier or cleaner through product mix. This theoretical result fits particularly well the empirical facts. [ABSTRACT FROM AUTHOR]

The product-mix problem is common and widely applicable in many industries. This paper formulates the product-mix problem for multiple production lines in sequenced stages where the output of the upstream stage is the input for other downstream operations. The objective is to maximize the upstream production (throughput per time) by which throughput of the whole system including the downstream operations will be maximized to satisfy production constraints: productivity, capacity, and sales requirements. The problem is formulated using an integer linear programming (ILP) model and demonstrated in a steel plant in Saudi Arabia. The 480-MT steel plant has six production lines, namely push-pickling line, cold-reversing mill, batch-annealing facility, temper mill, continuous galvanizing line, and color-coating line. The plant intended to leverage its annual production capacity. Hence, a recent expansion was done on the batch annealing facility. After the expansion, the plant had several production interruptions and stoppages in the downstream facilities. The model provided the maximum throughput for all production stages and avoids production interruptions. [ABSTRACT FROM AUTHOR]

During the years, number of authors have argued against of possible non-optimality of throughput accounting product mix preference. Lastly, Linhares (2009) criticized throughput accounting heuristics in expanded product mix selection of Blackstone (2001). It is shown in this work that throughput accounting still outperforms any other approach in this referred hypothetical situation, if overall capacity availability of a constraint resource and total throughput per week delivered are being considered (vs. only using throughput per minute of a product). It is critical to expand own point of view to the profit of a system, instead of solely justify decisions on shorter time units, which are not the same with the decision period. However, as we illustrate further, throughput accounting has still its caveats, which arise especially from step-wise increasing operating expenses or from the requirement of integer product mixes. These could be addressed properly by analyzing situation as illustrated in this research work, or alternatively using expert systems concerning customers and operations optimization. Impacts of these actions on short-term profitability are significant. [ABSTRACT FROM AUTHOR]

We contribute to the yet limited evidence on the relationship between trade liberalisation and a firm's product mix and diversification strategies for an emerging economy, Turkey. Lower import barriers foster firms’ specialisation in their core products. A drop in import tariffs, indeed, enhances a firm's propensity to drop fringe varieties and favours production growth of core products. More importantly, it favours firms’ specialisation in more sophisticated goods. Export tariff cuts, instead, by relaxing competitive pressure at home and lowering the cost to export, only reduce the firms’ incentive to innovate. [ABSTRACT FROM AUTHOR]

Theory of constraints (TOC) has emerged as an effective management philosophy suggesting practical solutions to various complex problems including product mix problem. Scholars have shown the superiority of various optimization (and artificial intelligence) approaches over the TOC-based heuristic to a “static” product mix problem, but have failed to see TOC as a whole, i.e. to take into consideration the impact of resource inter-dependencies, feedback loops, and importantly, statistical fluctuations ever present in any dynamic business environment. We proposed a system dynamics (SD) based simulation model to investigate product-mix problem under stochastic demand and scrap rates. We analyzed various scenarios by employing the drum-buffer-rope approach and constraint focused systematic scrap rate reduction approach, and importantly, evaluating performance using throughput accounting based global measures such as throughput and inventory. We conclude this paper by suggesting that future research efforts should be directed to develop an enabling hybrid expert simulation system to learn fundamental and powerful concepts underlying the theory of constraints. [ABSTRACT FROM AUTHOR]

The article presents the results of a study that assesses effects of selected marketing tactics on parents' loyalty towards the educational institutions. The results of Multiple Regression Analysis show that the price mix was the most significant factor having impact on parents' loyalty followed by people mix, place mix, product mix, and promotion mix. Furthermore, educational institution image mediates completely (full mediation) the relationship between selected marketing tactics (product mix, people mix, place mix, promotion mix) and parents' loyalty. Whereas, educational institution image mediates partially (partial mediation) the relationship between price mix and parents' loyalty. The sample comprised 687 respondents. [ABSTRACT FROM AUTHOR]

Product mix influences the performance of pull production control strategy in multi-product manufacturing systems. The complexity of product mix on the performance of a manufacturing system is primarily based on the characteristics of the demand and production control strategies. Demands are mainly characterised by volume and product-type while production control strategy is characterised by material release time, part flow, inventory control and throughput times. In multi-product systems, pull production control strategy operates dedicated or shared Kanban allocation policy. This paper examines the performance of the Generalised Kanban Control Strategy (GKCS), Extended Kanban Control Strategy (EKCS) and Basestock Kanban-CONWIP (BK-CONWIP) control strategy operating Shared Kanban Allocation Policies (S-KAP) or Dedicated Kanban Allocation Policies (D-KAP) for a healthcare parallel/serial assembly line with setup times. A simulation based multi-objective optimisation technique was adopted to examine the effect of different product mixes on the strategies and policies. A ranking and selection technique for multiple systems was used to screen the performance of the strategies. It was shown that product mix variability in a system influence the inventory levels of the pull control strategies examined. However, the performances of the strategies vary with strategies operating S-KAP having better inventory control than strategies operating D-KAP. Similarly, BK-CONWIP outperformed its alternatives. [ABSTRACT FROM AUTHOR]

The shipbuilding industry in recent times has witnessed a decline in the demand for commercial ships and a sharp increase in the demand for offshore plants. In response to this change in the industry, shipbuilding companies have sought an optimal product mix for producing commercial ships and offshore plants with minimal additional investment in facilities. This study was aimed at optimizing the pre-erection (P.E.) area partition for ship and offshore blocks based on the forecasted product mix of the planning horizon. The offshore P.E. area requires additional investment in facilities because the blocks are usually much heavier than those of ships. For given production schedules, and taking the flexibility of the forecasted change into consideration, we determined the optimal P.E. area partition ratio using the dynamic layout problem methodology. In this study, material handling cost, operating cost, rearrangement cost, and additional P.E. area construction cost were used to determine the optimal division. The optimal division of the P.E. area for offshore plants was then determined for a 10-year planning horizon. The results were applied to a shipyard to evaluate their business feasibility. [ABSTRACT FROM AUTHOR]

Abstract: In the real world of production, there are some uncertain parameters such as capacity, profit, and processing time. On the other hand, the fuzzy sets theory is applied as a suitable tool for managing production where dynamicity of the production environment prevents from determining target function, constraints and other parameters of the model. In this paper, a genetic algorithm embedded in fuzzy revised theory of constraints is presented for product mix problems. Results of implementing the proposed algorithm show efficiency and flexibility of this algorithm. [Copyright &y& Elsevier]

Notwithstanding the wide-spread inclusion of product-mix decisions in marketing simulation games, little theoretical work has been done to ensure that the algorithms driving them reflect current knowledge regarding product-mix strategy. Recent work based on relationship marketing theory has sought to address this problem strategically, focusing on the impact of demand correlation within the product mix. This article extends this line of research to a tactical level, using Goldratt’s theory of constraints to address the impact of supply constraints on product-mix interactions. It shows how these factors can be incorporated into a standard simulation objective function. [ABSTRACT FROM PUBLISHER]

Identification and determination of products and their quantities according to available resources is called product mix problem in manufacturing plants. One of the efficient and easy to use algorithms for solving product mix problems in uncertainty conditions is Fuzzy Revised Theory of Constraints (FRTOC) that was proposed by Azadegan et al. (). Their algorithm had a complete neighborhood search. So, it needed a long process to calculate the best result when demands of products were too much. Therefore, according to abilities of simulated annealing (SA) algorithm, we proposed a hybrid algorithm based on FRTOC and SA. In other words, the SA method is used instead of searching all neighbors in FRTOC. Also, a numerical example is used to show the capabilities of the proposed algorithm in comparison with the FRTOC. [ABSTRACT FROM AUTHOR]

Abstract: The integrated product mix-outsourcing optimization is a major problem in manufacturing enterprise. Generally, heuristic or meta-heuristic solution approaches are used to optimize such problems. Heuristic approaches for these problems include Theory of Constraints (TOC) and Standard Accounting. Sometimes heuristic approaches are inefficient especially in large problems and instead, in these cases meta-heuristic algorithms have been applied extensively. In this paper a novel meta-heuristic algorithm “Imperialist Competitive Algorithm” (ICA) is applied to solve the integrated product mix-outsourcing optimization problem. Also, the results obtained from ICA are compared with the results of TOC and Standard Accounting approaches. [ABSTRACT FROM AUTHOR]

This article uses the short-sightedness metaphor to explain the more limited vision of the brand, understood to be the sign of identity of a product. As the brand is a sign, it resorts to semiotics, the science of signs, to apply a model that expands the concept of brand to three dimensions: the sign of identity per se; the object to which the sign relates; and the market's response to the sign. [ABSTRACT FROM AUTHOR]

Abstract: This paper addresses the short-term capacity planning problem in a make-to-order (MTO) operation environment. A mathematical model is presented to aid an operations manager in an MTO environment to select a set of potential customer orders to maximize the operational profit such that all the selected orders are fulfilled by their deadline. With a given capacity limit on each source for each resource type, solving this model leads to an optimal capacity plan as required for the selected orders over a given (finite) planning horizon. The proposed model considers regular time, overtime, and outsourcing as the sources for each resource type. By applying this model to a small MTO operation, this paper demonstrates a contrast between maximal capacity utilization and optimal operational profit. [Copyright &y& Elsevier]

In the semiconductor industry, dynamic changes in demand force companies to change the product mix frequently and periodically. Assigning tight but attainable due dates is a great challenge under the circumstances that the product mix changes periodically. In this paper, we consider the due-date assignment problem for wafer fabrication and present a due-date assignment model to set manufacturing due dates satisfying the target on-time-delivery rate. The contamination model is applied to tackle the effect of that product mix varies periodically. We demonstrate the effectiveness and accuracy of the proposed model by solving a real-world example taken from a wafer fabrication shop floor in an IC manufacturing factory. [ABSTRACT FROM AUTHOR]

In the semiconductor industry, dynamic changes in demand force companies changing the product mix makes the production planning challenging. This paper aims at an environment where product mix changes periodically and presents a production scheduling system to plan the wafer lot release and throughput. The proposed system is designed on the make-to-stock basis with the objective of meeting demand forecast while maintaining production smoothness. Two modules are included in the system. Preliminary analysis module analyzes throughput and cycle time distributions for different product mixes so as to determine relative parameters to be used as the inputs to the job releasing plan. In the production scheduling module, with the considerations of the attainment of demand forecast, production smoothness, and commitment of the due dates of the released job orders, the job release schedule and completion time table are prepared. A simulation model of a semiconductor fab is used as the base case to demonstrate the effectiveness and efficiency of the proposed system. [ABSTRACT FROM AUTHOR]

In recent years, theory of constraints (TOC) has emerged as an effective management philosophy that has successfully tackled the problems of profit maximization with known demonstrated bottleneck in traditional as well as modern manufacturing plants. One of the key components of TOC application is to enumerate quantity of the various products to be produced keeping in view the system constraints and this is termed as the TOC product mix decision problem. It is a well-known computationally complex problem and thus warrants the application of heuristics technique or AI based optimization tools to achieve near optimal solutions in real time. To accomplish this objective a new algorithm, Psycho-Clonal has been proposed that works on the principle of artificial immune system and behavioral theory, namely Maslow's need hierarchy theory. Intensive computational experiments have been carried out and superiority of proposed heuristic on a given dataset is established. It is observed that results obtained are better compared to what have been achieved by the TOC heuristic, revised theory of constraint heuristic (RTOC), integer linear programming (ILP) , and tabu search based approaches. [ABSTRACT FROM AUTHOR]

In a competitive market, a company needs to utilize its available capacity efficiently in order to acquire high profit. The purpose of this paper is to present effective approaches to find a set of product mix optimal for the company to achieve the optimal manufacturing. Analytic hierarchy process (AHP) and analytic network process (ANP) approaches are taken to analyse multiple process inputs and outputs, incorporating experts’ opinion on their priority of importance, to obtain optimal product mixes for semiconductor production. The results provide guidance to the fabricator regarding strategies for accepting orders to maximize the manufacturing efficiency and the profit, while simultaneously considering other important input and output factors for maintaining manufacturing smoothness. [ABSTRACT FROM AUTHOR]

Increasing automation of wafer foundries in Taiwan has heightened the demand to automate dispatching decisions in recent years. To attain a better global performance, dispatching decisions should be made based on critical shop floor information. In this study, we present a dispatching scheme which combines move control and weighted due date concepts, genetic algorithm (GA) and simulation. The move control and weighted due date concept is applied to identify important dispatching decision factors respecting performance indices of due-date satisfaction and throughput. The GA is employed to derive proper weights for those decision factors. A simulation procedure capable of simultaneously considering product mix, reentrant process, and the influence of random events on the shop floor is developed to evaluate the system performance based on the derived weights of decision factors. A case study involving a simplified and revised data set from a Taiwanese wafer foundry is presented. Results show that the dispatching scheme proposed in this paper is effective and outperforms six conventional dispatching rules (FIFO, SPT, SRPT, EDD, SLACK, and CR) on performance measures of due date satisfaction, throughput, WIP level, critical machine utilization, and mean cycle time under both CONWIP and uniform release policies. [ABSTRACT FROM PUBLISHER]

During pneumatic control system design, the critical value for choosing the appropriate pneumatic actuator is the weight of the workpiece. In the case of flexible production systems, which are the core part of the Industry 4.0 (I4.0) concept, the weight of the workpieces is often variable, since the crucial feature of this kind of production is its ability to deal with variable parts. Therefore, in order to deal with the variable weight of parts, a pneumatic actuator is chosen according to the heaviest part. However, according to another I4.0 principle, energy efficient operation of machines, the previous criteria for choosing a pneumatic actuator is energy efficient only when handling the heaviest part. In all other cases, operation of the pneumatic actuator is suboptimal in terms of energy efficiency. Aiming to solve this problem, this paper considers the possibility of using a new pressure regulator instead of traditional manually adjusted pressure regulators. This regulator provides operating pressure modification in real-time in accordance with the weight of the workpieces. In this way, the optimal compressed air consumption is ensured for each workpiece. Implementation of this device has yielded significant energy savings; however, the value is variable and depends on working task characteristics. [ABSTRACT FROM AUTHOR]