Toward Improving Food Safety in the Domestic Environment: A Multi-Item Rasch Scale for the Measurement of the Safety Efficacy of Domestic Food-Handling Practices

To reduce consumer health risks from foodborne diseases that result from improper domestic food handling, consumers need to know how to safely handle food. To realize improvements in public health, it is necessary to develop interventions that match the needs of individual consumers. Successful intervention strategies are therefore contingent on identifying not only the practices that are important for consumer protection, but also barriers that prevent consumers from responding to these interventions. A measure of food safety behavior is needed to assess the effectiveness of different intervention strategies across different groups of consumers. A nationally representative survey was conducted in the Netherlands to determine which practices are likely conducted by which consumers. Participants reported their behaviors with respect to 55 different food-handling practices. The Rasch modeling technique was used to determine a general measure for the likelihood of an average consumer performing each food-handling behavior. Simultaneously, an average performance measure was estimated for each consumer. These two measures can be combined to predict the likelihood that an individual consumer engages in a specific food-handling behavior. A single "food safety" dimension was shown to underlie all items. Some potentially safe practices (e.g., use of meat thermometers) were reported as very difficult, while other safe practices were conducted by respondents more frequently (e.g., washing of fresh fruit and vegetables). A cluster analysis was applied to the resulting data set, and five segments of consumers were identified. Different behaviors may have different effects on microbial growth in food, and thus have different consequences for human health. Once the microbial relevance of the different consumer behaviors has been confirmed by experiments and modeling, the scale developed in the research reported here can be used to develop risk communication targeted to the needs of different consumer groups, as well as to measure the efficacy of different interventions.     

基于混合智能算法的电子市场供应链期权合同协调

在电子市场环境下,考虑了需求、市场价格和市场准入程度的随机性,基于Stack-erlberg主从对策,建立了供应链期权合同协调的随机期望值模型。在这一主从对策模型中,主方供应商的目标函数是预期利润,决策变量是期权合同预订费用和执行费用;从方分销商的目标函数是预期利润,决策变量是订货量。应用包括随机模拟、人工神经元网络和遗传算法组成的混合智能算法求解该主从对策问题。最后,结合上海宝钢集团益昌公司电子商务的运作实例,运用混合智能算法进行了仿真计算与分析。     

资金约束条件下的垄断企业策略性退出模型研究

传统的垄断企业退出模型没有考虑资金约束问题,通过研究双寡头企业在资金约束条件下如何从需求不断萎缩的产业退出的问题:首先描述了双寡头垄断企业策略性退出的基本模型,然后引入资金约束变量,分析企业资金实力如何影响和决定退出时机和顺序。结果表明,虽然不具备策略优势并且也将在消耗战中遭受损失,但雄厚的资金实力能保证企业在退出博弈中胜出,并且获得最后的垄断利润。因此,拥有雄厚资金实力的垄断企业的最优策略通常是继续保留在市场中,而不是传统模型中所指出的由于不具有策略优势而最先退出。     

A probabilistic epidemiological model for infectious diseases: The case of COVID-19 at global-level

This study has developed a probabilistic epidemiological model a few weeks after the World Health Organization declared COVID-19 a pandemic (based on the little data available at that time). The aim was to assess relative risks for future scenarios and evaluate the effectiveness of different management actions for 1 year ahead. We quantified, categorized, and ranked the risks for scenarios such as business as usual, and moderate and strong mitigation. We estimated that, in the absence of interventions, COVID-19 would have a 100% risk of explosion (i.e., more than 25% infections in the world population) and 34% (2.6 billion) of the world population would have been infected until the end of simulation. We analyzed the suitability of model scenarios by comparing actual values against estimated values for the first 6 weeks of the simulation period. The results proved to be more suitable with a business-as-usual scenario in Asia and moderate mitigation in the other continents. If everything went on like this, we would have 55% risk of explosion and 22% (1.7 billion) of the world population would have been infected. Strong mitigation actions in all continents could reduce these numbers to, 7% and 3% (223 million), respectively. Although the results were based on the data available in March 2020, both the model and probabilistic approach proved to be practicable and could be a basis for risk assessment in future pandemic episodes with unknown virus, especially in the early stages, when data and literature are scarce.     

Configuring a new business model through conceptual combination: The rise of the Huffington Post

How a successful business model (BM) is designed is a key question in the business model innovation (BMI) literature. Delving on the shared concept of BM as a configuration of components and interdependencies, we take a cognitive perspective to study the conceptual combination as a central process in BMI. We investigate the complexity of conceiving a new BM configuration, through a longitudinal study of the emergence of “The Huffington Post” which combined newspaper and blog in a disruptive and successful BM. With our research we theoretically frame the dynamic interplay between the three cognitive mechanisms of conceptual combination and the system of interdependent components of an emerging BM. Our findings unveil how the overall process unfolds and specifically delves into the dynamic iteration of composing and experimenting with the new configuration until the overall coherence is reached. Hence, we advance the literature by showing how the conceptual combination of a new BM is a complex effort and comprises some iterative cycles, vital to reach a coherent configuration which could secure a superior performance.     

合作社多元社会化服务的社员增收效应——基于山东省农户调研数据的“反事实”估计

基于山东省果蔬种植户的实地调查数据,采用内生转换回归模型(ESR)与因果中介分析模型(CMA),从社会化服务供给异质性视角检验了参加合作社对农户家庭务农收入的影响效果及作用机理。结果表明:参加合作社具有明显的促农增收效应;合作社的社会化服务有效供给对成员家庭务农收入的提升存在显著的因果中介效应,其中金融信贷服务、技术培训服务和生产流程服务对成员家庭务农收入提升的平均因果中介效应依次递增;尚无证据表明产品销售服务对成员务农收入存在显著影响。因此,在引导和鼓励农户加入合作社的同时,应重视强化合作社的社会化服务功能,适度扩大合作社的社会化服务供给规模。     

差价合约下电网公司购电费用最小化的离散优化模型

以购电费用最小化为目标函数,构建了差价合约下电网公司在合约市场、现货市场、备用市场和可中断负荷交易市场上的最优购电模型,并利用启发式算法给出了该模型的求解算法,最后,通过算例分析了差价合约及合约电量比重对电网公司购电费用的影响。     

提前期、构建成本和短缺量拖后率均可控的EOQ模型

传统库存模型通常将提前期和构建成本视为不可控制。事实上可以通过追加投资缩短提前期和降低构建成本。缺货期间,为减少订单丢失量和补偿顾客的损失,供应商会给予一定的价格折扣。现实库存系统中,容易得到需求的期望值和标准差,但较难得到其分布规律。基于此,考虑短缺量拖后率与价格折扣和缺货期间库存水平相关,提出了一种需求为任意分布且提前期和构建成本均可控的EOQ模型,证明了模型存在唯一最优解,给出了一种寻优算法。数值仿真分析表明,一般情况下,压缩提前期和降低构建成本能降低订购批量和安全库存,降低库存总成本;短缺量拖后系数和缺货概率对库存总成本影响较大,企业应尽量降低缺货概率,尤其在短缺量拖后系数较小时。     

供应链单向及双向期权柔性契约比较分析

在随机市场需求环境下,对于易逝品供应链合作契约的数量柔性问题,建立了两种不同期权模式的柔性契约模型。通过对模型的求解与分析,得出了不同契约下销售商的订货策略,而且销售商在双向期权契约下比在单向看涨期权契约时的期权购买量要小,初始订货量要大,但总的预期订货量要小。销售商在两种期权契约模式下的总的最优订货量均大于传统订货方式下总的最优订货量。两种期权契约均可以提高销售商总的订货量,但在具体契约参数下,两者在接近供应链最优订货量上存在差异。     

三级供应链应对突发事件的价格折扣契约研究

针对一个供应商-制造商-零售商构成的三级供应链,在考虑随机性需求基础上,探讨突发事件对三级供应链的影响,同时改进了协调供应链的价格折扣契约,使之具有抗突发事件性,并讨论利润分配情况,最后通过仿真给出具体的算例.