Inventory inaccuracies in the wholesale supply chain

The inventory level shown in the Information System contrary to popular belief and assumptions in most academic papers and in spite of the considerable amounts invested in information technology, is often inaccurate. The inventory inaccuracy occurs when the inventory shown in the Information System is not in agreement with the actually available inventory. In this paper, we first describe the major factors generating inventory inaccuracy. Then, we provide situations permitting to manage an inventory system subject to errors. We provide a general framework permitting to model the inventory inaccuracy issue. In particular, we link the inaccuracy issue with the well known random yield problem. The shown link permits us to derive the optimal ordering policy of an inventory framework where demand satisfaction is done based on the inventory records (which are subject to inaccuracies). We also propose an analysis permitting to show the added value of an advanced identification system such as the RFID technology.     

榆树林油田水井钻关的几点认识

文章针对榆树林油田加密区水井钻关状况进行分类分析,得出了不同钻关时间内钻关区产量递减趋势:钻关时间3个月以内,区块开发状况基本保持稳定;钻关三个月后,产量有所下降,且随着钻关时间的增加,递减幅度增大。同时根据钻关区特点提出几点建议,为今后控制钻关区产量递减提供指导。     

Is There a Viable Market for Area-Based Crop Insurance?

The performance of area yield insurance and farm-level multiple peril crop insurance is analyzed for cotton and soybean production in Georgia and South Carolina. The analysis improves on many previous studies by utilizing actual farm-level yield data and by comparing the two types of insurance products not only for actuarially fair premium rates but also for actual unsubsidized and subsidized premium rates. Results suggest that, even in heterogeneous production regions, area yield insurance may be a viable alternative to farm-level insurance when premium rates for farm-level insurance contain large positive wedges.     

基于GRA&BPNN的广西粮食产量预测研究

[目的]研究粮食产量的影响因素并以其相关性为基础预测粮食产量对实现广西粮食产业的"做强做优"具有重大意义。通常情况下粮食产量与种植技术发展水平、农田耕地面积、土地肥力、气候等诸多因素相关,但是在样本数据不足、数据间关联度不明显的情况下则无法采用回归分析、灰系统等常用预测方法。[方法]文章应用灰色关联分析方法得到水库水量、农田有效灌溉面积、第一产业从业人口、播种面积、除涝面积等5个与广西粮食产量关系最为密切的因子变量,同时取2004~2012年的数据作为学习、训练样本,以2013~2014年的数据为试报样本,并以此建立BP神经网络粮食预测模型。[结果]检验结果表明运用本模型预测粮食产量具有较高的精度和良好的泛化性。[结论]根据模型结果,该文提出提升广西粮食产业发展的可行性建议,即加强水库的管理、引导与粮食产业相关的产业、稳定粮食种植面积、加强洪涝灾害的防御和治理能力、推进农业信息化。     

人口,土地和农业生产力水平:二十世纪初无锡农村地区人口压力的测量

论文把"生存压力"和"劳动力剩余"作为测量"人口压力"的两个具体指标,在对20世纪初无锡农村地区人口,土地和农业生产力水平详细考察分析的基础上,对20世纪初无锡农村地区的人口压力进行了测量。论文从"人均土地粮食收获水平"和"剩余劳动力规模"两方面讨论了当时无锡农村经济所面临的资源困境,以及其有可能的发展出路。论文认为在当时那种沉重的人口压力下,提高农业生产力水平和发展工业和城市经济是实现农业经济增长和农村经济转型的关键。然而,就是在当时全国工业和城市经济最为发达的江南,其当时的工业和城市经济发展程度也远不足以吸收足够多的农村剩余劳动力,在资金和技术上对农业生产予以显著的支持,为农村经济发展带来本质性的变化。     

Pricing of off‐balance sheet debt: how do bond market participants use the footnote disclosures on operating leases and postretirement benefit plans?

In this study, we examine whether the public debt market prices information on off‐balance sheet debt arising from operating leases and postretirement plans. We find that bond‐rating agencies price off‐balance sheet debt arising from operating leases and the coefficient on off‐balance sheet debt measure of operating leases is similar to that of capital leases on the balance sheet. Regarding postretirement benefit plans, we find that bond‐rating agencies do price postretirement benefit obligations that are reported in balance sheet but do not price such obligations disclosed in footnotes. We find similar results when we examine corporate bond yields on new debt issues.     

基于多源遥感数据的马铃薯收入保险应用研究

目的 研究面向创新型农业保险业务中缺少及时准确的第三方作物产量结果用于灾损理赔的问题。引入多源卫星遥感测产技术,识别测产关键因子,构建产量模型。方法 文章运用多元线性回归分析方法,选取山西省马铃薯主产县岚县为研究区,计算基于Sentinel2影像的植被指数,结合气象卫星数据与实测单产数据,筛选关键因子,建立马铃薯单产遥感测产经验模型。结果 采用GF-2影像分割与Sentinel2长势时序识别岚县马铃薯种植面积为8 477.65hm²,精度检验Kappa值为0.72。保险公司岚县承保马铃薯面积2 476.37hm²,承保覆盖率为29.21%。测产结果显示,马铃薯单产与区域关键期地表温度参数相关性较好,岚县遥感测产获得平均单产为13.76 t/hm²,实地测产获得平均单产为14.06 t/hm²,误差百分比为2.13%,分乡镇平均误差百分比为22.97%,基本满足理赔业务需求。在2018年保险期结束后一周内,保险公司启动快速赔付,支付赔款125.29万元,赔付率48.46%。结论 遥感测产具有大范围、时效性好、可靠性高等特点,能够迅速为创新型保险产品提供测产理赔结果,提高理赔效率,保障农民收入。     

不同培养时间对决明子芽菜生物学产量和黄酮含量的影响

本文使用控温豆芽机恒温20℃培养决明子芽菜,研究不同培养时间(5 d、7 d、9 d、11 d和13 d)对决明子芽菜生物学产量和黄酮含量的影响。结果表明,决明子芽菜的胚根长度、子叶长度、胚轴长度、单株鲜重和单株净菜重在培养7 d采收时均高于5 d采收,且差异显著,7 d后各指标数值虽呈增加趋势,但是差异不显著。黄酮含量随生长期增加不断增加,但在5 d、7 d、9 d和11 d之间差异不显著,13 d时采收黄酮含量最高为16.17 mg·g^-1,且与之前不同生长期差异显著。综合生物学产量、黄酮含量及时间成本决明子芽菜培养7 d即可以进行采收。     

Ranking Crop Yield Models: A Comment

This comment discusses key specification issues that may have affected the performance and, therefore, the ranking of parametric models that were compared in a recent AJAE article. A procedure to obtain the most flexible parametric model specification possible, given the particular probability distribution function on which the model is based is presented. These specifications also allow for standardized and, therefore, more valid comparisons across parametric models that are based on different probability distributions. Finally, the comment cautions against generalization of the rankings in that AJAE article and recommends that these more flexible specifications be adopted in future comparisons and applications.