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991.
基于"制销分离"与"定制一体"两种结构选择,构建个性化产品供应链处于非竞争与竞争环境下的博弈模型,在引入一个实际案例的基础上,运用算例仿真比较分析两种运营模式下的供应链运作策略和盈利差异。结果显示:与制销分离结构相比,个性化产品供应链选择定制一体结构,有利于匹配产品个性化制造、提升产品个性化水平和市场需求、增加供应链的期望收益;个性化产品供应链选择制销分离结构时,适度的批发价格激励能够提升产品个性化水平、更好满足消费者个性化需求、改善供应链的运营绩效,分销商适度让利加大批发价格激励力度可显著促进产品个性化制造互动、提升产品个性化水平;竞争将消减个性化产品供应链的运营绩效,但选择定制一体结构可显著提升竞争力。 相似文献
992.
现实中频发的信息安全事件使人们借助微博等社交媒体发表看法、宣泄情感,形成网络舆情,社交媒体上情感的宣泄使网民群体情感的波动在信息安全突发事件网络舆情的治理中产生重要的作用。然而,已有研究较多关注网络集群行为本身,较少有研究对信息安全突发事件网络舆情中网民群体情感的形成机理进行深入探讨。
在此背景下,对信息安全突发事件网络舆情中网民群体情感的形成机理进行研究,提出情感领袖和集群情感的概念,分析微博中信息安全突发事件的用户评论数据获得情感分类和情感得分,采用社会网络分析与文本情感分析结合的方法识别情感领袖,借助情感传播分层网络建立集群情感传播模型,分析集群情感的演变过程并描绘其传播网络,挖掘情感领袖在信息安全突发事件中的集群情感效应。
以360云盘关闭事件为研究案例,研究结果表明,此案例微博评论中负面情感所占比例较大;情感领袖在集群情感的形成中产生群际情感效应和群际认同效应,并且在情感领袖的情感传播过程中促进新的集群情感产生;不同情感类型的领袖引发的群际效应趋于一致,即都使新的集群情感强度减弱;情感复杂度先增强后减弱,并且随着集群情感整体规模的扩大,集群中情感表达为中性的情感比例增大。
研究结果表明,信息安全突发事件网络舆情传播中存在情感领袖,并且情感领袖会在集群间产生群际效应,揭示了信息安全突发事件网络舆情中网民群体情感的形成机理,丰富了对情感领袖在信息安全突发事件网络舆情方面的群际效应研究。研究结果对网络舆情监管部门如何利用情感领袖的群际作用治理信息安全突发事件网络舆情具有指导意义。 相似文献
993.
Lack of a valid instrument to measure learning transfer predictors has been the major obstacle hindering Human Resource Development (HRD) professionals from moving forward. This problem is one of the lingering HRD issues in South Korea, in which human resources have been strategically emphasized as a critical asset due to the scarcity of natural resources. To address this issue, this study aims at testing the validity and reliability of the data collected with the Korean Learning Transfer System Inventory (LTSI) Version 4. A sample of 753 managers from 16 Korean industries was divided into two subsamples for exploratory and confirmatory factor analyses. Reliability and the effect of common method variance on the factor structure were examined, with the results suggesting that the LTSI is valid for use in the Korean industry. 相似文献
994.
The widely used empirical Bayes (EB) and full Bayes (FB) methods for before–after safety assessment are sometimes limited because of the extensive data needs from additional reference sites. To address this issue, this study proposes a novel before–after safety evaluation methodology based on survival analysis and longitudinal data as an alternative to the EB/FB method. A Bayesian survival analysis (SARE) model with a random effect term to address the unobserved heterogeneity across sites is developed. The proposed survival analysis method is validated through a simulation study before its application. Subsequently, the SARE model is developed in a case study to evaluate the safety effectiveness of a recent red‐light‐running photo enforcement program in New Jersey. As demonstrated in the simulation and the case study, the survival analysis can provide valid estimates using only data from treated sites, and thus its results will not be affected by the selection of defective or insufficient reference sites. In addition, the proposed approach can take into account the censored data generated due to the transition from the before period to the after period, which has not been previously explored in the literature. Using individual crashes as units of analysis, survival analysis can incorporate longitudinal covariates such as the traffic volume and weather variation, and thus can explicitly account for the potential temporal heterogeneity. 相似文献
995.
In this paper we devise the stochastic and robust approaches to study the soft-capacitated facility location problem with uncertainty. We first present a new stochastic soft-capacitated model called The 2-Stage Soft Capacitated Facility Location Problem and solve it via an approximation algorithm by reducing it to linear-cost version of 2-stage facility location problem and dynamic facility location problem. We then present a novel robust model of soft-capacitated facility location, The Robust Soft Capacitated Facility Location Problem. To solve it, we improve the approximation algorithm proposed by Byrka et al. (LP-rounding algorithms for facility-location problems. CoRR, 2010a) for RFTFL and then treat it similarly as in the stochastic case. The improvement results in an approximation factor of \(\alpha + 4\) for the robust fault-tolerant facility location problem, which is best so far. 相似文献
996.
Hsing-Yen Ann Chang-Biau Yang Chiou-Ting Tseng 《Journal of Combinatorial Optimization》2014,28(4):800-813
In this paper, we revisit a recent variant of the longest common subsequence (LCS) problem, the string-excluding constrained LCS (STR-EC-LCS) problem, which was first addressed by Chen and Chao (J Comb Optim 21(3):383–392, 2011). Given two sequences \(X\) and \(Y\) of lengths \(m\) and \(n,\) respectively, and a constraint string \(P\) of length \(r,\) we are to find a common subsequence \(Z\) of \(X\) and \(Y\) which excludes \(P\) as a substring and the length of \(Z\) is maximized. In fact, this problem cannot be correctly solved by the previously proposed algorithm. Thus, we give a correct algorithm with \(O(mnr)\) time to solve it. Then, we revisit the STR-EC-LCS problem with multiple constraints \(\{ P_1, P_2, \ldots , P_k \}.\) We propose a polynomial-time algorithm which runs in \(O(mnR)\) time, where \(R = \sum _{i=1}^{k} |P_i|,\) and thus it overthrows the previous claim of NP-hardness. 相似文献
997.
针对大型复杂企业维修任务集的多服务需求点和多样化需求特征,基于服务需求视角,定义一类多服务需求点下的MRO服务资源配置问题,建立以MRO服务提供商整体服务成本为优化目标,同时考虑资源紧张度、信任度和多服务需求点不同工期要求的问题模型;针对模型中的关键参数(即服务成本和资源紧张度)的特征进行分析,并给出相应的度量方法;在此基础上,设计改进的模拟植物生长算法实现求解,算法通过启发式获得初始可行解,并进行敏感性分析。研究结果表明, MRO服务资源配置模型和算法是可行和有效的,服务成本的波动、信任度和资源紧张度的变化对于资源配置结果均有影响,模型能够有效提高维修服务成本的估算能力,同时能够保持MRO服务提供商资源配置的稳定性。 相似文献
998.
Peter Brown Yuedong Yang Yaoqi Zhou Wayne Pullan 《Journal of Combinatorial Optimization》2017,33(2):551-566
The linear sum assignment problem is a fundamental combinatorial optimisation problem and can be broadly defined as: given an \(n \times m, m \ge n\) benefit matrix \(B = (b_{ij})\), matching each row to a different column so that the sum of entries at the row-column intersections is maximised. This paper describes the application of a new fast heuristic algorithm, Asymmetric Greedy Search, to the asymmetric version (\(n \ne m\)) of the linear sum assignment problem. Extensive computational experiments, using a range of model graphs demonstrate the effectiveness of the algorithm. The heuristic was also incorporated within an algorithm for the non-sequential protein structure matching problem where non-sequential alignment between two proteins, normally of different numbers of amino acids, needs to be maximised. 相似文献
999.
Adaptive two-echelon capacitated vehicle routing problem (A2E-CVRP) proposed in this paper is a variant of the classical 2E-CVRP. Comparing to 2E-CVRP, A2E-CVRP has multiple depots and allows the vehicles to serve customers directly from the depots. Hence, it has more efficient solution and adapt to real-world environment. This paper gives a mathematical formulation for A2E-CVRP and derives a lower bound for it. The lower bound is used for deriving an upper bound subsequently, which is also an approximate solution of A2E-CVRP. Computational results on benchmark instances show that the A2E-CVRP outperforms the classical 2E-CVRP in the costs of routes. 相似文献
1000.
A hamiltonian walk of a digraph is a closed spanning directed walk with minimum length in the digraph. The length of a hamiltonian walk in a digraph D is called the hamiltonian number of D, denoted by h(D). In Chang and Tong (J Comb Optim 25:694–701, 2013), Chang and Tong proved that for a strongly connected digraph D of order n, \(n\le h(D)\le \lfloor \frac{(n+1)^2}{4} \rfloor \), and characterized the strongly connected digraphs of order n with hamiltonian number \(\lfloor \frac{(n+1)^2}{4} \rfloor \). In the paper, we characterized the strongly connected digraphs of order n with hamiltonian number \(\lfloor \frac{(n+1)^2}{4} \rfloor -1\) and show that for any triple of integers n, k and t with \(n\ge 5\), \(n\ge k\ge 3\) and \(t\ge 0\), there is a class of nonisomorphic digraphs with order n and hamiltonian number \(n(n-k+1)-t\). 相似文献