影响最大化问题是在社交网络上找到一组有影响力的用户,使得期望的影响范围最大化。然而,已有的研究工作没有考虑用户之间有效的传播时间区间,而且忽略了营销时间对于选取初始用户的影响。基于真实用户动作日志,确定了用户之间有效的传...影响最大化问题是在社交网络上找到一组有影响力的用户,使得期望的影响范围最大化。然而,已有的研究工作没有考虑用户之间有效的传播时间区间,而且忽略了营销时间对于选取初始用户的影响。基于真实用户动作日志,确定了用户之间有效的传播时间区间,并提出了一个基于时间的影响力分配模型(influence power allocating model based on time,IPAT)。根据该模型,提出了基于真实时间的影响力最大化问题(influence maximization problem based on time,IMPT)和饥饿营销模式中种集最小化问题(seed set minimization problem in hungry marketing,SMPHM),并证明了这两个问题都是NP-hard问题。为求解IMPT问题和SMPHM问题,分别提出了有效的近似算法A-IMPT(algorithm for IMPT)和A-SMPIB4(algorithm for SMPHM),并证明了算法A-IMPT和A-SMPHM的近似比。多个真实社交网络数据集上的实验验证了算法AMT和A-SMPHM的有效性和高效率。展开更多
One of the objectives of the 1257/99 EU regulation was that rural populations should be able to gain an extra income. This regulation may not be any longer in force, but soon a new one will replace it. The plantations...One of the objectives of the 1257/99 EU regulation was that rural populations should be able to gain an extra income. This regulation may not be any longer in force, but soon a new one will replace it. The plantations that are created by Greek farmers more specifically the plantations of poplar trees-have a ten-year rotation at least. This means that the time between the establishment of the plantation and the harvest is high. As a consequence, during this time, the market environment （e.g. prices） may face substantial changes. Frequently, these changes are so immense that producers are driven in economic distress. This situation is also linked to the domestic timber supply and imports, and as a result to the product prices. Concerning the market prices of poplar trees, one additional factor that has probably deteriorated the situation is the E.U. expansion. This paper examines a case study in North Greece. Vital conclusions are made which may be useful for the Greek and E.U. decision makers regarding the process of dealing with current issues such as the 1257/99 regulation replacement （1698/2005）.展开更多
文摘影响最大化问题是在社交网络上找到一组有影响力的用户,使得期望的影响范围最大化。然而,已有的研究工作没有考虑用户之间有效的传播时间区间,而且忽略了营销时间对于选取初始用户的影响。基于真实用户动作日志,确定了用户之间有效的传播时间区间,并提出了一个基于时间的影响力分配模型(influence power allocating model based on time,IPAT)。根据该模型,提出了基于真实时间的影响力最大化问题(influence maximization problem based on time,IMPT)和饥饿营销模式中种集最小化问题(seed set minimization problem in hungry marketing,SMPHM),并证明了这两个问题都是NP-hard问题。为求解IMPT问题和SMPHM问题,分别提出了有效的近似算法A-IMPT(algorithm for IMPT)和A-SMPIB4(algorithm for SMPHM),并证明了算法A-IMPT和A-SMPHM的近似比。多个真实社交网络数据集上的实验验证了算法AMT和A-SMPHM的有效性和高效率。
文摘One of the objectives of the 1257/99 EU regulation was that rural populations should be able to gain an extra income. This regulation may not be any longer in force, but soon a new one will replace it. The plantations that are created by Greek farmers more specifically the plantations of poplar trees-have a ten-year rotation at least. This means that the time between the establishment of the plantation and the harvest is high. As a consequence, during this time, the market environment （e.g. prices） may face substantial changes. Frequently, these changes are so immense that producers are driven in economic distress. This situation is also linked to the domestic timber supply and imports, and as a result to the product prices. Concerning the market prices of poplar trees, one additional factor that has probably deteriorated the situation is the E.U. expansion. This paper examines a case study in North Greece. Vital conclusions are made which may be useful for the Greek and E.U. decision makers regarding the process of dealing with current issues such as the 1257/99 regulation replacement （1698/2005）.
