基于遗传算法的有折扣多产品采购多供应商选择问题求解

针对传统供应商选择过程大多只面向单一供应商进行选择的局限性,本文以质量、价格、交货期和交货提前期为评价指标,以最小化综合评价值为目标,纳入供应商供货能力和价格折扣,建立面向多供应商采购多产品条件下供应商选择的数学模型,并提出基于改进遗传算法的模型求解方法。实证分析验证了本文提出的求解方法的有效性。     

考虑供应商产品交付水平的供应链融资策略研究

供应商产品的交付水平直接影响下游制造商的生产，但是这种现象没有得到供应链金融研究的重视。为此，本文将供应商交付水平和供应链的运营融资问题结合起来研究。在考虑供应商产品交付水平的情况下，通过研究资金不足的供应商分别利用制造商预付款融资和风险投资方股权融资时，供应商的最优运营决策和融资策略，最后考虑了供应商对两种融资方式的选择。研究结果表明，供应商的自有资金水平对供应链均衡决策及其收益影响很大，有限的自有资金严重制约了供应商产品的交付水平，降低了供应链的运作效率；不管是资金充足，还是选择融资，供应商的利润不仅与自身的运营效率有关系，而且与替代供应商产品的批发价格有很大关系，当供应商的运营效率较低时，供应商的利润随着替代供应商产品的批发价格先增大后减小，当供应商运营效率较高时，供应商的利润随着替代供应商产品的批发价格逐渐增大。当供应商进行融资时，若自有资金水平较低，应通过股权融资的方式进行融资，若自有资金水平较高，供应商应该选择制造商预付款的方式进行融资，若自有资金量超过预付款融资时供应商所需资金的阈值时，供应商选择不融资。     

Fit between sourcing capabilities and organisational structure on IT outsourcing performance

Thus far, relatively few studies on the supplier side of Information Technology (IT) outsourcing arrangements have been based on empirical quantitative research. Previous research identified a recurring supplier problem, a lack of sustainability in IT performance. The literature revealed that a supplier's capabilities and organisational structure affect the supplier performance. We hypothesise that realising a fit between the necessary sourcing capabilities and organisational structure on the IT supplier side will result in a sustainable sourcing performance. We executed a survey research among employees involved in sourcing activities of three different IT outsourcing suppliers (N?=?135). The results from our analysis provide evidence that these constructs can be used to analyse differences between the three types of service suppliers. Results indicate that suppliers who focus on establishing a fit are more willing or able to monitor if they achieve a sustainable performance.     

Single vs. multiple objective supplier selection in a make to order environment

The problem of allocation of orders for custom parts among suppliers in make to order manufacturing is formulated as a single- or multi-objective mixed integer program. Given a set of customer orders for products, the decision maker needs to decide from which supplier to purchase custom parts required for each customer order. The selection of suppliers is based on price and quality of purchased parts and reliability of on time delivery. The risk of defective or unreliable supplies is controlled by the maximum number of delivery patterns (combinations of suppliers delivery dates) for which the average defect rate or late delivery rate can be unacceptable. Furthermore, the quantity or business volume discounts offered by the suppliers are considered. Numerical examples are presented and some computational results are reported.     

How does information sharing affect first-tier suppliers’ flexibility? Evidence from the automotive industry in Sweden

This study addresses the critical research issue of how supplier delivery performance can be enhanced by integrating information sharing into volume and delivery flexibility. This study developed a research model to relate information sharing on demand forecasts and inventory data between original equipment manufacturers (OEMs) and first-tier suppliers. Based on a sample of 52 suppliers from automotive industry in Sweden, partial least squares structural equations modelling (PLS-SEM) was used to assess the model. The results confirm that sharing demand forecasts is a key enabler of supplier volume and delivery flexibility while sharing inventory data is not. The study contributes to enlarging the knowledge about supply chain management from the suppliers’ perspective. It also contributes to knowledge by validating the conceptual model and operationalisation of constructs. The study also has practical contribution in which management should focus on improving communication and collaboration practices with OEMs for effective sharing of demand forecasts.     

A Multi‐Supplier Sourcing Problem with a Preference Ordering of Suppliers

We study a sourcing problem faced by a firm that seeks to procure a product or a component from a pool of alternative suppliers. The firm has a preference ordering of the suppliers based on factors such as their past performance, quality, service, geographical location, and financial strength, which are commonly included in a supplier scorecard system. Thus, the firm first uses available inventory from supplier 1, if any, then supplier 2, if any, and so on. The suppliers differ in costs and prices. The buyer firm seeks to determine which suppliers to purchase from and in what quantities to maximize its total expected profit subject to the preference ordering constraint. We present the optimal solution to this problem, and show that it has a portfolio structure. It consists of a sub‐set of suppliers that are ordered by their underage and overage costs. This portfolio achieves a substantial profit gain compared to sourcing from a unique supplier. We present an efficient algorithm to compute the optimal solution. Our model applies to component sourcing problems in manufacturing, merchandizing problems in retailing, and capacity reservation problems in services.     

A Structural Analysis of the Effectiveness of Buying Firms' Strategies to Improve Supplier Performance

Many manufacturing firms have increased the amount of component parts and services they outsource, while refocusing on their core capabilities. Outsourcing parts and services to independent, external suppliers means that suppliers' performance is increasingly critical to the long‐term success of these buying firms. Buying firms are increasingly using disparate supplier development strategies to improve supplier performance including supplier assessment, providing incentives for improved performance, instigating competition among suppliers, and direct involvement of the buying firm's personnel with suppliers through activities such as training of suppliers' personnel. Using resource‐based theory, internalization theory, and structural equation modeling, we examine the impact of these supplier development strategies on performance. We conclude that direct involvement activities, where the buying firm internalizes a significant amount of the supplier development effort, play a critical role in performance improvement.     

Investment in Shared Suppliers: Effect of Learning,Spillover, and Competition

We investigate the optimal strategies for firms to invest in their suppliers when the benefits of such investments can spillover to other firms who also source from the same suppliers. We consider two Bayesian firms that can invest in improving the quality of their shared supplier; the firms do not have complete information on the true quality of the supplier, but they update their beliefs based on the supplier's performance. We formulate the problem as an investment game and obtain Markov perfect equilibria characterized by the investment thresholds of both firms. The equilibrium investment strategies of the two firms are characterized by a region of preemption and a region of war of attrition. We also examine how the interplay between spillover, competition, and returns from the investment at shared suppliers affect the investment threshold and the time to the leader's investment, and identify the conditions under which competition delays or hastens the first investment in a shared supplier.     

Joint supplier selection and scheduling of customer orders under disruption risks: Single vs. dual sourcing

This paper presents a stochastic mixed integer programming approach to integrated supplier selection and customer order scheduling in the presence of supply chain disruption risks, for a single or dual sourcing strategy. The suppliers are assumed to be located in two different geographical regions: in the producer's region (domestic suppliers) and outside the producer's region (foreign suppliers). The supplies are subject to independent random local disruptions that are uniquely associated with a particular supplier and to random semi-global (regional) disruptions that may result in disruption of all suppliers in the same geographical region simultaneously. The domestic suppliers are relatively reliable but more expensive, while the foreign suppliers offer competitive prices, however material flows from these suppliers are more exposed to unexpected disruptions. Given a set of customer orders for products, the decision maker needs to decide which single supplier or which two different suppliers, one from each region, to select for purchasing parts required to complete the customer orders and how to schedule the orders over the planning horizon, to mitigate the impact of disruption risks. The problem objective is either to minimize total cost or to maximize customer service level. The obtained combinatorial stochastic optimization problem will be formulated as a mixed integer program with conditional value-at-risk as a risk measure. The risk-neutral and risk-averse solutions that optimize, respectively average and worst-case performance of a supply chain are compared for a single and dual sourcing strategy and for the two different objective functions. Numerical examples and computational results are presented and some managerial insights on the choice between the two sourcing strategies are reported.     

An investigation into E-business service in the UK telecommunication manufacturing industry

Nowadays, suppliers’ product and service quality has risen in importance with a manufacturer’s push to develop core competencies and capitalise on global operations and markets. However, due to the complex features of business service, suppliers are facing significant challenges in providing service effectively and developing business collaboration. This is further complicated by the development of information and communication technologies (ICTs). This paper thus attempts to investigate the factors influencing buyers’ e-service (EBS) requirements and the impact of these requirements on business collaboration. Based on a questionnaire survey with 500 UK telecommunication manufacturers, this research identifies buyers’ different EBS requirements for different types of suppliers and the impact of ICTs on EBS requirements. While for suppliers our findings provide insights into buyers’ EBS requirements, they can help buyers to develop appropriate supplier selection criteria. The findings also contribute to a better understanding of the development of buyer and supplier business collaboration.     

具有双重角色和非期望要素的供应商评价两阶段DEA模型

在基于DEA方法的供应商评价过程中,会出现供应商同时具有双重角色要素和非期望输出要素的情形。文章提出了一个处理双重角色要素的新思路,认为DEA模型中双重角色要素同时扮演了输入和输出两个角色,所有双重角色要素本质上就是网络DEA模型中的中间变量,并同时认为包含双重角色要素的生产系统一定能分解成为多个子系统,其中的双重角色要素既是一个子系统的输入,同时又是另一个子系统的输出。为测度供应商的效率,基于已有关系型两阶段DEA模型,将供应商的生产运营视为两阶段过程,其双重角色要素视为两阶段过程的中间变量,并通过将所有输出以加权和的形式表达,但对非期望输出用负的权重的方式,提出了一个具有双重角色和非期望输出要素的供应商评价两阶段DEA模型,最后用一个实例验证了方法的可行。     

Supplier integration and firm performance: the moderating effects of internal integration and trust

This study proposes and empirically tests a model of the moderating effects of internal integration and trust on the impacts of information, process and strategic integration with suppliers on firm performance using structural equation modelling and data collected from 261 manufacturing firms in Vietnam. The results show that all three types of supplier integration positively associate with firm performance. Internal integration enhances the impact of process integration with suppliers on firm performance, but does not moderate the impacts of information and strategic integration with suppliers. Internal trust has insignificant, positive and negative influences on the effects of information, process and strategic integration with suppliers on firm performance. The findings show that internal integration and trust play different roles in moderating the positive effects of information, process and strategic integration with suppliers on firm performance, which elucidates a possible reason for previous mixed findings on the relationship between supplier integration and firm performance.     

Push or Pull? Auctioning Supply Contracts

Consider a buyer, facing uncertain demand, who sources from multiple suppliers via online procurement auctions (open descending price‐only auctions). The suppliers have heterogeneous production costs, which are private information, and the winning supplier has to invest in production capacity before the demand uncertainty is resolved. The buyer chooses to offer a push or pull contract, for which the single price and winning supplier are determined via the auction. We show that, with a pull contract, the buyer does not necessarily benefit from a larger number of suppliers participating in the auction, due to the negative effect of supplier competition on the incentive of supplier capacity investment. We thus propose an enhanced pull mechanism that mitigates this effect with a floor price. We then analyze and compare the outcomes of auctions for push and (enhanced) pull contracts, establishing when one form is preferred over the other based on the buyer's profits. We also compare our simple, price‐only push and pull contract auctions to the optimal mechanisms, benchmarking the performance of the simple mechanisms as well as establishing the relative importance of auction design and contract design in procurement auctions.     

A high-quality-supplier selection model for supply chain management and ISO 9001 system

Supplier selection process for supply chain management (SCM) and ISO 9001 quality management system environments is considered. Determining suitable suppliers in the supply chain has become a key strategic consideration. However, the nature of these decisions is usually complex and unstructured. This paper proposes a high-quality-supplier selection (HQSS) model to deal with supplier selection problems in supply chain management. In selecting a supplier, quality management factors are considered first, and then price, delivery, etc. Quality management factors include a quality management audit, product testing, engineering work force, capability index, training time, etc., based on a five-interval scale. Next, the HQSS model determines the final solution by considering factors such as price, production lead-time, and delivery time.     

Improving supplier performance using a comprehensive scheme

Improving and coordinating buyer and supplier efforts to increase productivity and competitive advantage in a supply chain is an important issue. Numerous studies have proposed models, principles and criteria for supplier evaluation and selection. Hence, evaluating and improving supplier performance are important when building long-term supply chain competitiveness. This study presents a novel and comprehensive framework that illustrates the linkages between evaluating supplier performance and planning improvements. The proposed framework comprises four parts: building an evaluation model, evaluating supplier performance based on the buyer perspective, evaluating supplier performance based on the supplier perspective and scheduling improvement tasks. This study applies a hybrid genetic algorithm to help suppliers schedule improvement tasks based on the evaluation findings. Finally, evaluation data of a light-emitting diode (LED) manufacturer in Taiwan is used to interpret the procedure and verify model effectiveness.     

Exploring the Importance of Business Clockspeed as a Moderator for Determinants of Supplier Network Performance*

As the importance of supplier networks becomes increasingly recognized as a vital factor to company performance, researchers and practitioners alike are focusing their attention on this subject. The study's main objective is to test the specific hypotheses that effective use of Information Technology (IT) and the depth of company relationships with suppliers are directly related to Supplier Network (SN) performance, and that industry clockspeed moderates these relationships. A convenience sample of 135 manufacturing organizations was used to empirically test these hypotheses. Our results indicate that clockspeed does moderate the relationship between IT use effectiveness and supplier network performance. The same is true in the case of supplier relations depth, and hence, managers are encouraged to pay attention to the items comprising network performance as a determinant of supplier network performance.     

基于多重结算方式的装配系统协同问题研究

鉴于装配系统中存在的众多不确定因素,制造商往往采取延迟付款(货齐付款)的方式来降低供应商供货不同步的风险,而供应商则倾向于采用及时付款(货到付款).本文以装配系统为研究对象,分别针对延迟付款和及时付款方式建立了两供应商对单制造商的准时供货模型,考虑当每个零部件的供货提前期均不确定时,供应商和制造商应该如何进行相应的生产...     

Requirement or Promise? An Analysis of the First‐Mover Advantage in Quality Contracting

Quality contracting is critical and challenging due to the many unique issues related to quality. In this study, we analyze the first‐mover right in quality contracting by considering two different strategies for the buyer: the quality requirement strategy (QR) where buyer moves first by posting quality requirement to suppliers and quality promise strategy (QP) where buyer voluntarily gives up the first‐mover right to suppliers to ask them to promise quality. We study which strategy (1) better encourages suppliers' quality improvement efforts and (2) leads to a higher expected profit for the buyer. To analyze the drivers behind the buyer's choice between QR and QP, we start with the basic model where buyer faces only one supplier who has the opportunity to make quality improvements. We then gradually add other business features such as information asymmetry and supplier competition, analyzing how each feature adds/changes the driving forces and how they interact in the buyer's decision between QR and QP. We consider both the case where the wholesale price is fixed (when the buyer has the power to dictate price or price is set by the market) and the case where the wholesale price is included as a variable (when price is part of the negotiation). We find that QP always leads to the first‐best quality efforts from the supplier(s) while QR limits their efforts. However, this does not guarantee higher expected profit for the buyer under QP. We provide insightful guidelines in buyer's choice between QP and QR. This research enriches the limited literature on quality contracting with quality improvement opportunity and asymmetric information.     

Selection of supply portfolio under disruption risks

This paper deals with the optimal selection of supply portfolio in a make-to-order environment in the presence of supply chain disruption risks. Given a set of customer orders for products, the decision maker needs to decide from which supplier to purchase custom parts required for each customer order to minimize total cost and mitigate the impact of disruption risks. The selection of suppliers and allocation of orders is based on price and quality of purchased parts and reliability of delivery. The two types of disruption scenarios are considered: scenarios with independent local disruptions of each supplier and scenarios with local and global disruptions that may result in all suppliers disruption simultaneously. The problem is formulated as a single- or bi-objective mixed integer program and a value-at-risk and conditional value-at-risk approach is applied to control the risk of supply disruptions. The proposed portfolio approach is capable of optimizing the supply portfolio by calculating value-at-risk of cost per part and minimizing expected worst-case cost per part simultaneously. Numerical examples are presented and some computational results are reported.