For supply chain that mainly depend on core enterprises, this paper presents a three-layer production planning control model, and the algorithm with examples for the production planning.

针对以核心企业为主的供应链，提出了三层生产计划控制模型并给出了其节点企业内部生产计划的具体算法与运行实例。

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The model consists of three layers-meta term layer, production knowledge layer, and rule layer.

该模型包括元概念层、生产知识层、规则层。

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The Montreal Protocol is the international agreement designed to protect the ozone layer by phasing out production of Cfc's and halons.

BBC: News | Sci/Tech | Ozone hole reaches record size

But if doctors can preserve remaining insulin production in their new patients, they might someday be able to layer on other drugs that would prod the insulin-producing cells to slowly regenerate.

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