Joint location-inventory problem with differentiated service levels using critical level policy

This paper analyzes the design of a distribution network for fast-moving items able to provide differentiated service levels in terms of product availability for two demand classes (high and low priority) using a critical level policy. The model is formulated as a MINLP with chance constraints for which we propose a heuristic to solve it. Although the heuristic does not guarantee an optimal solution, our computational experiments have shown that it provides good-quality solutions that are on average 0.8% and at worst 2.7% from the optimal solution.     

Exploiting the monthly data flow in structural forecasting

A quarterly stochastic general equilibrium (DSGE) model is combined with a now-casting model designed to read timely monthly information as it becomes available. This implies (1) mapping the structural quarterly DSGE with a monthly version that maintains the same economic restrictions; (2) augmenting the model with a richer data set and (3) updating the estimates of the DSGE׳s structural shocks in real time following the publication calendar of the data. Our empirical results show that our methodology enhances the predictive accuracy in now-casting. An analysis of the Great Recession also shows that our framework would have helped tracing the DSGE׳s structural shocks in real time, obtaining, for example, a more timely account of the 2008 contraction.     

Cost-effectiveness of asenapine in the treatment of bipolar I disorder patients with mixed episodes

Objective:

Around one-third of patients with bipolar I disorder (BD-I) experience mixed episodes, characterized by both mania and depression, which tend to be more difficult and costly to treat. Atypical antipsychotics are recommended for the treatment of mixed episodes, although evidence of their efficacy, tolerability, and cost in these patients is limited. This study evaluates, from a UK National Health Service perspective, the cost-effectiveness of asenapine vs olanzapine in BD-I patients with mixed episodes.

Methods:

Cost-effectiveness was assessed using a Markov model. Efficacy was informed by a post-hoc analysis of two short-term clinical trials, with response measured as a composite Young Mania Rating Score and Montgomery-Åsberg Depression Rating Scale end-point. Probabilities of discontinuation and relapse to manic, mixed, and depressive episodes were sourced from published meta-analyses. Direct costs (2012–2013 values) included drug acquisition, monitoring, and resource use related to bipolar disorder as well as selected adverse events. Benefits were measured as quality-adjusted life years (QALYs).

Results:

For treating mixed episodes, asenapine generated 0.0187 more QALYs for an additional cost of £24 compared to olanzapine over a 5-year period, corresponding to a £1302 incremental cost-effectiveness ratio. The higher acquisition cost of asenapine was roughly offset by the healthcare savings conferred through its greater efficacy in treating these patients. The model shows that benefits were driven by earlier response to asenapine during acute treatment and were maintained during longer-term follow-up. Results were sensitive to changes in key parameters including short and longer-term efficacy, unit cost, and utilities, but conclusions remained relatively robust.

Conclusions:

Results suggest that asenapine is a cost-effective alternative to olanzapine in mixed episode BD-I patients, and may have specific advantages in this population, potentially leading to healthcare sector savings and improved outcomes. Limitations of the analysis stem from gaps in clinical and economic evidence for these patients and should be addressed by future clinical trials.     

大城市客运交通系统出行方式特性分析

以我国大城市客运交通系统为研究对象,对各出行方式的出行距离与出行时耗分别进行了分布拟合。研究发现,采用k阶爱尔朗分布拟合表现出良好的适用性。在出行距离方面,小汽车与自行车的出行距离分布随机性最大,常规公交次之,城市轨道交通相对来说出行距离随机性最小;在出行时耗方面,自行车的时耗分布最为集中,小汽车与出租车次之,常规公交与城市轨道交通出行时耗分布范围最广。     

The unholy marriage? Integrating qualitative and quantitative information in Delphi processes

This study analyses the strengths, weaknesses and pitfalls encountered when combining qualitative and quantitative information in a Delphi process and when reporting the results as scenarios or images of the future. The paper draws material from seven Disaggregative Policy Delphi processes conducted in Finland in 1999-2008, in which the authors were researchers or advisors. The cases are analysed in terms of the level of integration and the ways to overcome the difficulties. A learning ‘community of practice’ was created by these afterthoughts and by organising an international conference workshop on the issue. Qualitative and quantitative material was holistically integrated in one case. In the other cases, solutions led to domination of one material type over another but even then the other material did give relevant points to scenario formation. Finally, we give recommendations for tackling the pitfalls: 1) balancing between qualitative and quantitative, 2) balancing between formal structure and questions raised in the process, 3) framing questions to discover alternative future states, 4) paying attention to panellists' style, 5) dealing with lack of data for comprehensive cluster analysis, 6) considering scenario consistency, 7) understanding manager's responsibility and, 8) understanding the epistemological aspects of Delphi data. We conclude that integrating qualitative and quantitative material by using mixed methods to form coherent scenarios is at the same time desirable, possible and difficult - making the ‘unholy marriage’ a worthy adventure.     

波长色散X射线荧光光谱法同时测定氧化铁皮中的多种杂质元素

采用偏硼酸锂和四硼酸锂混合熔剂熔融法制样,波长色散X射线荧光光谱法同时测定了氧化铁皮中的铝、铜、钙、硅、镁、锰、钛、锌、磷等多种杂质元素。考察了熔剂、脱模剂以及预氧化条件等对熔片的影响;采用理论α系数校正了基体效应和元素间的干扰效应,方法的检出限在4.7-35.0μg/g之间。用本方法测定氧化铁皮试样中各杂质元素的相对标准偏差在0.4%-5.1%之间,分析结果与其他方法测定值一致。与化学法相比,该方法快速、简便、精密度好、准确度高。     

Mixed markets and crime

This paper specifies and solves a two-stage, game theoretic model of a mixed market for crime control. In the first stage of the model, private targets and the government choose levels of policing. In the second stage, criminals choose targets and the severity of the crimes that they commit.The paper's key results are as follows. First, private policing can both divert crime to targets that lack private protection and also increase the severity of the crime that these less-protected targets suffer. Second, an increase in private policing reduces the aggregate expenditure on traditional policing. This is an instance of a political incentive externality, where private policing affects the objective function of the government. Specifically, it reduces the level of traditional policing that is consistent with the Samuelson condition for efficient provision of a public good. Third, the substitution of private for public policing carries with it a change in the technology of policing. In effect, private policing leads to a shift from enforcement and punishment towards monitoring and target hardening. This, in turn, may lead to an increase in the severity of crime. Fourth, the mixed policing equilibrium is inefficient, and, in some situations, mixing may reduce the utility of all targets.     

我国社保资金管理层次优化设想

对社会保障资金管理绩效和安全性的追求，必然会引发对其管理层次问题的关注。分析我国当前面临的困境和挑战及国外现有管理模式之利弊，我国社保资金的管理层次模式可从以下方面进行创新：法治分权架构；科学的职权划分；资金运行的NGO与政府组织的混合竞争；复合监控。     

The periurban city: why to live between the suburbs and the countryside

The last 30 years have witnessed the emergence of a new pattern of urban development in France, called the periurban belt. It is defined as a belt outside the city occupied both by households and farmers. We develop a residential model in which households commuting to an employment center may choose to live with farmers in this mixed belt because they value the rural amenities created by farming activities. Both types of agents compete on the land market and the equilibrium conditions allow us to obtain an analytical solution and to provide some insights about the robustness of the periurban form against decreases in commuting costs. Finally, the model is calibrated on French data.     

Integrating qualitative and quantitative methods in research on international entrepreneurship

Using mixed methods is an often proposed but rarely used research design. In this paper, I describe a mixed method approach to research on international entrepreneurship. Using a mixed methods design with a case study and a mail survey, I show how the two methods make it possible to reach a better understanding of the antecedents of organizational memory and how organizational memory affects perceived costs of further international expansion of Swedish small and medium-sized enterprises (SMEs). I also propose research designs for studying both novel phenomena and for developing established theory through a combination of case studies and structural equation modeling.