A hybrid multi-agent negotiation protocol supporting supplier selection for multiple products with synergy effect

Supplier selection is an important problem in supply chain management. In practice, it is common for a purchasing company to procure a bundle of products simultaneously. In this regard, synergy effect could exist between products and hence affect the final choice of suppliers. It is therefore necessary to incorporate the synergy effect between products in supplier selection process. Agent-based negotiation models are applied to automate supplier selection process. Negotiation protocol is an essential component should be considered when building an effective agent negotiation model. The objective of this research is to propose a negotiation protocol special for multi-product supplier selection problem. The negotiation protocol is a hybrid multi-agent protocol of combinatorial procurement auction protocol and multi-bilateral bargaining protocol. The negotiation protocol is able to support the purchasing company and suppliers negotiate on the concrete commitments of multiple products simultaneously, and select suppliers for multiple products. In addition, both the purchasing company and suppliers can express their preferences on the synergy effect between products in negotiation process by adopting the negotiation protocol. Simulation is conducted to demonstrate the effectiveness and efficiency of the negotiation protocol.     

A model for performance monitoring of suppliers

The purchasing function is central to the strategic operations of effective supply chain management. This centrality is mainly due to the significant impact of material costs on profits, increased investments in inter-organizational advanced manufacturing and information technologies, and a growing emphasis on the just-in-time operations philosophy. The critical business processes of the purchasing function include supplier selection, negotiation of supply contracts, monitoring supplier performance, and acting as an interface between an organization and its suppliers. Within these core processes of purchasing, this paper narrows its scope to focus upon the supplier performance evaluation and monitoring process, which assists in maintaining effective customer-supplier linkages. While price has been traditionally considered as the single most important factor in evaluating suppliers, it has been agreed upon that value performance emphasis needs to include other important factors such as quality, delivery and flexibility. Given this evolving business competitiveness environment, the contribution of this research is threefold. First, it applies a new multi-criteria evaluation model for supplier performance evaluation by considering various performance criteria. Second, a proposed application extension of this model serves as a monitoring and control mechanism for the performance of suppliers, thus supporting continuous process improvement to achieve efficient customer-supplier relationships. Third, the paper presents this technique as a new methodological extension to data envelopment analysis research by improving the discriminatory power of an existing variable returns to scale model. The model and its application are demonstrated through a previously published illustrative case example.     

Integrated model for supplier selection and negotiation in a make-to-order environment

The paper deals with the development of an integrated supplier selection and negotiation process for multiple parts/materials procurement. The main objective is to integrate decisions in the internal supply chain of a make-to-order manufacturer. Two main decisions during the negotiation process are considered: (1) the manufacturing planning decision responsible for determining the production schedule and fabrication lot size and (2) the supplier selection decision concerning which suppliers are selected for company business and the order volume allocated to each selected supplier. The model is designed to support the negotiation process by generating a set of effective alternatives in each negotiation period. Its structure is multi-objective and non-linear. The combination of the interactive weighted Tchebycheff method and Benders decomposition method is applied to generate a set of effective alternatives to support the decision-maker in each negotiation period.     

A multi-agent protocol for multilateral negotiations in supply chain management

Within a supply chain network, it is common for companies to engage in negotiations to resolve conflicts in task allocation and order fulfilment problems. This kind of supply chain negotiation is usually regarded as buyer–seller negotiation. In recent years, multi-agent systems have been established to automate buyer–seller negotiations. However, most have limitations in handling complex negotiation scenarios such as multilateral negotiations and multi-issue negotiations. This paper presents ECNPro (the Extended Contract-Net-like multilateral Protocol), which is a new multi-agent protocol for handling buyer–seller negotiations in supply chain management. ECNPro is designed to handle agent bargaining and interactions in complex multilateral and multi-issue negotiations in which the buyer has to negotiate with many suppliers. The multi-attribute utility theory (MAUT) approach is adopted to establish the utility functions for a set of negotiation issues in the bargaining process. It adopts a multi-threaded approach to allow the buyer to bargain concurrently with multiple suppliers. ECNPro is able to split an order to more than one supplier to achieve a better negotiation payoff. In addition, mobile agents are employed in ECNPro, the buyer sends mobile agents to sites of the sellers to conduct bargaining locally. This approach improves the negotiation efficiency significantly.     

A hierarchical model for optimal supplier selection in multiple sourcing contexts

This paper addresses a crucial objective of the strategic purchasing function in supply chains, i.e. optimal supplier selection. We present a hierarchical extension of the data envelopment analysis (DEA), the most widespread method for supplier rating in the literature, for application in a multiple sourcing strategy context. The proposed hierarchical technique is based on three levels. First, a modified DEA approach is used to evaluate the efficiency of each supplier according to some criteria proposed by the buyer. Second, the well known technique for order preference by similarities to ideal solution (TOPSIS) is applied to rank the maximally efficient suppliers given by the previous step. Third and finally, a linear programming problem is stated and solved to find the quantities to order from each maximally efficient supplier in the multiple sourcing context. The presented approach is able to straightforwardly discern between efficient and inefficient partners, avoid the confusion between efficient and effective suppliers and split the supply in a multiple sourcing context. The hierarchical model is applied to the supply of a C class component to show its robustness and effectiveness, while comparing it with the DEA and TOPSIS approaches.     

Interdependent order allocation in the two-echelon competitive and cooperative supply chain

In this paper, we consider an order allocation problem in a two-echelon supply chain with multiple suppliers and multiple demanders. The orders from the demanders are interdependent in terms of execution sequence. We consider both the competition and cooperation relationships between the suppliers and demanders. We provide formal definition for the order allocation problem and propose a negotiation mechanism which includes a two-stage negotiation protocol and two heuristic negotiation algorithms. Different negotiation strategies are proposed for the demanders and suppliers to resolve the order interdependency and competition conflict. An automated negotiation approach is introduced to implement the negotiation mechanism. The computational experiments show that orders under different supply chain contexts can be allocated with high success rate. We also numerically compare the influence of different negotiation strategies and investigate the interaction of conflict resolutions.     

A supplier performance evaluation framework using single and bi-objective DEA efficiency modelling approach: individual and cross-efficiency perspective

In view of complexities associated with supplier performance evaluation based on traditional business criterions (such as costs, quality levels, and delivery timelines) and emerging criterions (such as those related to environmental sustainability), we in this research evolve two different supplier efficiency measurement models that unify such criterions possessing characteristics of both desirable and undesirable outputs. The first model is a single-objective DEA efficiency assessment model wherein both types of outputs are integrated into a single composite efficiency measure. Using data from suppliers of Hyundai Steel Company, we determine composite efficiencies of each of these suppliers thus ranking them in terms of an overall efficiency score that would be useful as far as the first-cut supplier discrimination is concerned. However, due to the relative inability of evolved single-objective efficiency model to perform trade-offs amongst desirable and undesirable outputs and, owing to unidimensionality aspects, we evolve a goal programming based bi-objective efficiency model wherein trade-offs can be performed between both conventional and emerging dimensions criterions leading to different supplier evaluations for varied scenarios. We also integrate our evolved models with the cross-efficiency view of efficiency determination in order to enable the decision-makers to achieve peer-to-peer evaluation and maximum discrimination amongst suppliers.     

A framework for defining both qualitative and quantitative supplier selection criteria considering the buyer–supplier integration strategies

Previous research has reported that the decision criteria used to evaluate suppliers differ by product category. This paper presents a framework for defining the supplier selection criteria by investigating possible quantitative and qualitative criteria reported by earlier studies according to the levels of buyer–supplier relationship, the company's competitive situation and its corporate strategies, rather than investigating these criteria in respect of product category. The solution proposed in this study not only assists decision makers to define selection criteria, but also supports determining the buyer–supplier integration level. An actual case in Audio Electronics, a Turkish electronics business, demonstrates the feasibility of applying the proposed framework in practice.     

Newsvendor problem with multiple unreliable suppliers

This paper focuses on supplier-related decisions in a newsvendor setting. We build upon the current literature by analysing the newsvendor problem with multiple unreliable and non-identical suppliers. We also incorporate both fixed ordering costs and capacity limits for supplier selection. We develop an exact algorithm to solve the problem optimally and a heuristic algorithm to solve the problem efficiently. Through structural properties of the optimal solution and a numerical study, we provide useful managerial implications regarding optimal sourcing strategies in complex supply chains. Previous literature concludes that with multiple unreliable (independent) suppliers, cost is the order qualifier and reliability is the order winner. We found that when fixed ordering costs and supply capacities exist, this insight no longer holds. We also examine the sensitivity of the sourcing decisions to supplier capacity levels, demand uncertainty, salvage value and shortage cost. Our results show that high levels of demand uncertainty lead firms to turn to a single-sourcing strategy whereas high salvage values and high shortage cost suggest multi-sourcing strategy.     

Supplier development: communication approaches,activities and goals

Operations managers rely on the purchasing function to obtain production inputs from suppliers and to ensure supplier performance. The link between supplier development activities performed by buying firms with their suppliers, in terms of operational outcomes and impact on competitive advantage for the buying firm has been well documented. However, a buying firm should, prior to setting up a supplier development program and investing in supplier development activities, establish goals it wants to achieve and determine how to achieve these goals. Until now, supplier development goals in general and their relationship with supplier development activities have received little research attention. The results from this empirical study suggest that the relationship between the goal to improve a supplier's capabilities and knowledge transfer from the buyer to the supplier firm is moderated by the degree of human interaction. Buying firms pursuing the strategy to improve supplier capabilities rely more intensively on training and co-location of buyer and supplier employees to leverage the knowledge transfer to the supplier firm.     

A supplier pre-selection model for multiple products with synergy effect

In practice, it is common for companies to purchase multiple products simultaneously. For the multiple required products, a large number of interested suppliers are involved. It is necessary for the purchasing company to shortlist a small number of qualified and competitive potential suppliers prior to finalising the suppliers for order fulfilment. In addition, synergy effect which is an effect arising between two or more products that produce an effect greater than the sum of their individual effects, could exist in the multi-product supplier selection environment. Since synergy effect between products can affect the choice of suppliers, it is also necessary to incorporate the synergy effect between products in the supplier selection for multiple products. However, few research efforts have been focused on the supplier pre-selection problem, let alone explicitly for multiple products with synergy effect. This paper presents a supplier pre-selection model for multiple products with synergy effect. The model is able to evaluate interested suppliers on the multiple pre-selection criteria, by the fuzzy Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)-based supplier pre-selection algorithm, and shortlist a small number of potential suppliers. Illustrative examples are conducted to demonstrate the function and application of the supplier pre-selection model for multiple products with synergy effect.     

Developing a resilient supply chain through supplier flexibility and reliability assessment

In this study, we examine the optimal allocation of demand across a set of suppliers in a supply chain that is exposed to supply risk and environmental risk. A two-stage mixed-integer programming model is used to develop a flexible sourcing strategy under disruptions. Our model integrates supplier selection and demand allocation with transportation channel selection and provides contingency plans to mitigate the negative impacts of disruptions and minimise total network costs. Finally, a numerical example is presented to illustrate the model and provide insights. The findings suggest that developing contingency plans using flexibility in suppliers’ production capacity is an effective strategy for firms to mitigate the severity of disruptions. We also show that flexibility and reliability of the suppliers and regions play a significant role in determining contingency plans for during disruption. Findings generally show that highly flexible suppliers receive less allocation, and their flexible capacity is reserved for disruptions. For firms that do not incorporate risk management into supplier selection and allocation, the recommendation is to source from fewer, more reliable suppliers with less risk of disruption. Our findings also emphasise that the type of disruption has important implications for supplier selection and demand allocation. This study highlights the supply chain risk management strategy of regionalising as a means for minimising the impact of environmental disruptions.     

An ascending price procurement auction for multiple items with unit supply

In this paper, a supply chain scenario is considered in which an original equipment manufacturer wishes to procure a set of items from a set of suppliers with private costs. Each supplier can provide at most one item. Two ascending price auctions are proposed to implement an efficient allocation for this model. The first converges to a unique competitive equilibrium price of the economy if suppliers bid truthfully. However, because no equilibrium strategy exists for the suppliers, a second auction is designed based on the first, which converges to a second unique competitive equilibrium price. Truthful bidding is a Bayesian Nash equilibrium strategy for suppliers in this auction. We show several practical advantages of our ascending auctions over traditional reverse auctions. Ascending auctions perform better than reverse auctions in two main aspects: (i) information revelation; and (ii) bidder cost determination. Simulation results are reported to validate these claims.     

Supplier selection problem revisited from the perspective of product configuration

Collaboration with suppliers is essential for developing and producing a competitive product and it begins with selecting the right suppliers. This article addresses the supplier selection problem from the perspective of product configuration. We discuss first how the conventional decision models of supplier selection should be extended, considering the fact that supplier configuration requires supplier selection for each subsystem of a product. We then highlight the need to consider interrelationships between suppliers, namely, supplier–supplier relationships during the selection process of the combination of suppliers. Finally, we introduce the supplier configuration graph in order to provide a clear picture of the problem. Discussions are provided along with an example of a smartphone configuration.     

A multi-agent architecture for multi-product supplier selection in consideration of the synergy between products

Supplier selection is an important task in purchasing. The performance of a supply chain depends on the selection of the right suppliers to provide the right materials or services at the right price and right time. Most of the research on supplier evaluation and selection assumes that products are procured independently. However, in reality, it is common for a purchasing company to procure a bundle of products together. In this regard, synergy could exist between products and hence affect the final choice of suppliers. It is therefore necessary for the purchasing company to incorporate the synergy between products in supplier selection. This paper presents a multi-agent system (MAS) architecture for multi-product supplier selection in consideration of the synergy between products. A three-phase supplier selection model is proposed to support multi-product procurement in consideration of the synergy between products. The three phases are, namely, product synergy determination phase, supplier pre-selection phase and negotiation-based final selection phase. The MAS is equipped with various types of autonomous function agents and different agent interaction protocols to effect the functioning of this three-phase multi-product supplier selection model.     

Supply chain network design with unreliable suppliers: a Lagrangian relaxation-based approach

This paper deals with the integrated facility location and supplier selection decisions for the design of supply chain network with reliable and unreliable suppliers. Two problems are addressed: (1) facility location/supplier selection; and (2) facility location/supplier reliability. We first consider the facility location and supplier selections problem where all the suppliers are reliable. The decisions concern the selection of suppliers, the location of distribution centres (DCs), the allocation of suppliers to DCs and the allocation of retailers to DCs. The objective is to minimise fixed DCs location costs, inventory and safety stock costs at the DCs and ordering costs and transportation costs across the network. The introduction of inventory costs and safety stock costs leads to a non-linear NP-hard optimisation problem. To solve this problem, a Lagrangian relaxation-based approach is developed. For the second problem, a two-period decision model is proposed in which selected suppliers are reliable in the first period and can fail in the second period. The corresponding facility location/supplier reliability problem is formulated as a non-linear stochastic programming problem. A Monte Carlo optimisation approach combining the sample average approximation scheme and the Lagrangian relaxation-based approach is proposed. Computational results are presented to evaluate the efficiency of the proposed approaches.     

军品包装供应商评价指标体系和方法研究

目的 为了实现快速响应、可靠高效的装备（器材）和物资保障,提高军事物流整体质量,对军品包装供应商进行科学管理。方法 构建军品包装供应商的筛选模型,确立评价指标体系,提出一种集历史、现状和未来为一体的新的综合评价方法,并进行算例验证。结果 通过采用科学的评价方法,对军品包装供应商进行综合评价和遴选,解决了军品包装产品筹措和采购环节由于供应商引起的不确定性问题,使军品包装产品质量得到了有效保证。结论 建立军品包装供应商选择和评价体系,是加强供应商管理的重要基础,也是现代军事物流的重要内容,对推动军品包装发展有重要意义。     

A genetic algorithm based grey goal programming (G3) approach for parts supplier evaluation and selection

The problem of part supplier selection is a major concern for all manufacturers when seeking to enhance the products’ quality and productivity. The objective of this paper is to propose an integrated genetic algorithm based grey goal programming (G³) approach to solve the part supplier selection problem. The main factor in part supplier selection is the assembly relation of the parts so as to find the suitable suppliers combination for the parts of a product. We first identify the main factors affected on supplier selection. We then present a grey-based goal programming model to work as the fitness function to evaluate the suppliers with respect to the total deviation the factors have from the ideal values. Since the objective is to find the best solution, a genetic algorithm is used to solve this problem for faster and better evaluation. The novelty of this integrated approach is to apply both qualitative and quantitative factors at once in one model and to use the grey theory to cover the lack of information of qualitative factors in order to find a solution in a near real situation.     

谈判能力不对称对供应商质量选择的影响分析

供应链成员的谈判能力不对称会影响供应商的质量改进投入.在谈判能力不对称情况下,建立一种供应商质量改进的决策模型,研究发现供应商的质量改进投入不能达到供应链最优水平.当供应商拥有较强谈判能力时,购买商对质量改进评价过程中存在的道德风险将降低供应商的质量改进投入;当购买商拥有较强谈判能力时,如果购买商提供给供应商长期的交易契约,质量改进投资风险率越大,供应商质量改进投入越低.经仿真比较,当供应商的初始质量较高时,供应商质量改进投入在购买商拥有较强谈判能力的情况下高于在供应商拥有较强谈判能力的情况.