仓库物资装卸最优性方案的选择

军队后方仓库是军用物资装备的储备基地，是军队物流系统的一个重要环节。如何利用现有条件，提高日常乃至战时仓库的收发、存储能力和工作效率，是提高军队后勤保障能力的一个重要课题。本文对仓库物资装卸中的几个主要技术经济指标进行探讨分析。     

Flexibility at different stages in the life cycle of projects: An empirical illustration of the “freedom to maneuver”

Many textbooks on project management present illustrations concerning the relative size of project attributes during different project phases. The derived models all have attributes in common, such as uncertainty, significance of decisions, and degree of freedom to maneuver, that are typically high in the beginning of the project and low in the end. At the same time, variables such as the accumulated cost and available information begin at low levels and end up at a high level at the end of the project. Based on empirical data from projects, this paper illustrates and quantifies one of these attributes, the freedom to maneuver, in different project phases.     

Decreasing trends in total suspended solids and cumulative effects of nonpoint source projects in the Cuyahoga River Watershed,OH

Using the US EPA’s Grants Reporting and Tracking System (GRTS), we test if completion of best management practices (BMPs) through the Clean Water Act Section (4)319 National Nonpoint Source Program was associated with a decreasing trend in total suspended solids (TSS) load (metric tons/year). The study area chosen had 21 completed projects in the Cuyahoga River watershed in northeastern Ohio from 2000 to 2018. The 4319 projects ranged from dam removal, floodplain/wetland restoration to stormwater projects. There was an overall decreasing trend in TSS loads. We identified three phases of project implementation and completion, where phase 1 had ongoing projects, but none completed (2000–2004). The steepest decrease in loads, identified as phase 2 (2005–2011), was associated with completion of low-head dam modification and removal projects on the mainstem of the Cuyahoga River. A likely decreasing trend was associated with projects completed in the tributaries, such as natural channel design restoration and stormwater green infrastructure (phase 3). Pairing sediment reduction estimates from projects with the river’s flow normalized TSS loading trend, we estimated that the 4319 effort may account for a small fraction of the TSS load reduction. Other stream restoration projects (non-4319) have also been done in the Cuyahoga watershed by other organizations. However, trying to compile these other projects is challenging in larger watersheds having multiple municipalities, agencies, and nonprofits doing restoration without better coordinated record keeping and monitoring. While a decreasing trend in a pollutant load is a desirable water quality outcome, determining what contributed to that trend remains difficult.     

The Load Model: an alternative to QALY

Background: QALYs are widely used in health economic evaluation, but remain controversial, largely because they do not reflect how many people behave in practice. This paper presents a new conceptual model (Load Model) and illustrates it in comparison with the QALY model.

Methods: Load is the average annual weight attributed to morbidity and mortality over a defined period, using weightings based on preference judgements. Morbidity Load is attributed to states of illness, according to their perceived severity. When people are in full health, Load is zero (no morbidity). Death is treated as an event with negative consequences, incurred in the year following death. Deaths may be weighted equally, with a fixed negative weight such as ?100, or differ according to the context of death. After death, Load is zero. In a worked example, we use the standard gamble method to obtain a weighting for an illness state, for both Load and QALY models. A judge is indifferent between certainty of 1.5 years’ illness followed by death, or a 50/50 chance of 1.5 years’ full health or 1-year illness, each followed by death. The weightings calculated are applied to a hypothetical life, 72 years in full health followed by 3 years with illness then death, using both models. Three other hypothetical outcomes are also compared.

Results: For an example life, the relative size of the morbidity component compared with the mortality component is much higher in the Load model than in the QALY model. When comparing alternative outcomes, there are also substantial differences between the two models.

Conclusions: In the Load model the weight of morbidity, relative to mortality, is very different from that in the QALY model. Given the role of the QALYs in economic evaluation, the implications of an alternative, which generates very different results, warrant further exploration.     

Global energy forecasting competition 2017: Hierarchical probabilistic load forecasting

The Global Energy Forecasting Competition 2017 (GEFCom2017) attracted more than 300 students and professionals from over 30 countries for solving hierarchical probabilistic load forecasting problems. Of the series of global energy forecasting competitions that have been held, GEFCom2017 is the most challenging one to date: the first one to have a qualifying match, the first one to use hierarchical data with more than two levels, the first one to allow the usage of external data sources, the first one to ask for real-time ex-ante forecasts, and the longest one. This paper introduces the qualifying and final matches of GEFCom2017, summarizes the top-ranked methods, publishes the data used in the competition, and presents several reflections on the competition series and a vision for future energy forecasting competitions.     

Impact of mortality reductions on years of schooling and expected lifetime labor supply

Hazan (2009) performs empirical analysis based on the conjecture that a necessary condition for mortality decline to cause longer years of schooling is that it also increases expected lifetime labor supply, and reaches controversial conclusions. We aim to examine the theoretical validity of Hazan’s (2009) conjecture, and more generally, to understand the relation between these two conditions in a standard life-cycle model. We find that the relation between the effects on optimal years of schooling and expected lifetime labor supply differs systematically with respect to mortality reductions at different stages of the life cycle. Based on these systematic differences, we find that longer lifetime labor supply is not sufficient for increased years of schooling for all mortality reductions occurring during the schooling phase, and not necessary for increased years of schooling for some mortality reductions during the working phase.     

Exploring the relationship between truck load capacity and traffic accidents in the European Union

Applying econometric techniques to EU28 panel data and controlling for explanatory variables such as road types, we find that increased truck load capacity does not necessarily aggravate road traffic safety. Specifically, heavy trucks do not seem to be linked with greater numbers of traffic fatalities/accidents, medium trucks appear to be the worst performers in terms of fatalities, and light trucks seem to be the worst for accidents. In summary, our results clarify the complex relationship between truck load capacity and road safety, pointing to the existence of a negative correlation for accidents per capita and an inverse U-shaped curve for fatalities per capita.     

A multi-objective sustainable load planning model for intermodal transportation networks with a real-life application

Growing importance of intermodal transportation necessitates modeling and solving load planning problems by taking into account various complex decisions simultaneously like transportation mode/service type selection, load allocation, and outsourcing. This paper presents a mixed-integer mathematical programming model for a multi-objective, multi-mode and multi-period sustainable load planning problem by considering import/export load flows to satisfy transport demands of customers and many other related issues. Several multiple objective optimization procedures are utilized in order to handle conflicting objectives simultaneously under crisp and fuzzy decision making environments. A real-life case study is also performed to present application and usefulness of the proposed model.     

Consumer Preferences for Coffee: Hot and Wet,or Quality and Flavor?

An econometric model is developed and estimated for all brands of coffee sold at the retail level in four supermarkets in Columbus, Ohio. These brands are segmented into 24 categories, and the four stores are classified into two groups, inner-city and suburban, based on 2010 census tract data. Using estimated measures of price-sensitivity, these 24 categories are further segmented into four groups to help guide and clarify the discussion. Estimated results show different purchasing patterns and different levels of price-sensitivity for inner-city and suburban shoppers. Further, these purchasing patterns and levels of price-sensitivity suggest alternative marketing strategies for retailers. Private-label coffee brands are shown to be quite competitive with many national brands, and indeed private-label brands command a market share among inner-city shoppers that is more than double that for the nation (21.95% vs. 9%).     

道路车辆电器及电子设备供电环境条件标准的抛负载试验剖析

新版ISO标准已将车载电器及电子设备的抛负载瞬间脉冲试验归人道路车辆电器电子的供电环境条件和试验范畴。本文通过介绍一些标准起草中的技术背景和标准文字中的未尽之言，以及一些试验实践中应予把握的要点，从而对于国家标准的制定、相关榆测部门的检测能力提升，以及车辆电器及电子设备品质的监控质量的提升有所帮助。