基于最小生成树理论的空间结构分解模型

现有空间结构分解模型存在测算结果不唯一及不满足传递性两大问题。本文提出了一种基于最小生成树理论的空间结构分解模型,在保证多个地区间比较传递性的同时,减小了结构分解模型测算结果不唯一性对模型应用的影响。基于我国地区投入产出表,本文以ICT产业区位商比较的五变量结构分解为例,示范了如何定义帕式—拉式偏离指数(PLS),建立了基于PLS指数的最小生成树,并将结论应用于空间结构分解,对该模型的有效性进行了验证。     

规模组合、因子定价与均值方差张成 --来自中国A股的证据

本文从均值方差张成的角度探讨了多因子定价模型在中国的适用性,并对规模组合能否作为定价因子这一问题进行了实证考察。对沪深两市A股的10个规模组合的均值方差张成检验表明,大、中、小3个规模组合在短期内可以张成所有的规模组合的均值方差边界,这意味着这3个规模组合可以作为定价因子,解释其他风险资产收益率的变动。     

Spanning with futures contracts

Regression-based testing techniques have long been used to quantify whether the efficient frontier of a set of assets spans the frontier of a larger collection of investments. This paper derives regression-based spanning tests for the case in which the investment possibilities set contains, or is constituted by, futures contracts for which marked-to-market margins are explicitly taken into account. Two empirical applications illustrate our results.     

Solving dynamic public insurance games with endogenous agent distributions: Theory and computational approximation

We make two contributions in this paper. First, we extend the characterization of equilibrium payoff correspondences in history-dependent dynamic policy games to a class with endogenously heterogeneous private agents. In contrast to policy games involving representative agents, this extension has interesting consequences as it implies additional nonlinearity (i.e., bilinearity) between the game states (distributions) and continuation/promised values in the policymaker’s objective and incentive constraints. The second contribution of our paper is in addressing the computational challenges arising from this payoff-relevant nonlinearity. Exploiting the game’s structure, we propose implementable approximate bilinear programming formulations to construct estimates of the equilibrium value correspondence. Our approximation method respects the property of upper hemicontinuity in the target correspondence. We provide small-scale computational examples as proofs of concept.     

Zusammenarbeit zwischen organisatorischen Gruppen: Ein Literaturüberblick über die Intergroup Relations-, Schnittstellen- und Boundary Spanning-Forschung

Zusammenfassung Die Zusammenarbeit zwischen organisatorischen Gruppen (Abteilungen, Projektteams etc.) leistet einen entscheidenden Beitrag zur Effizienz und Effektivität von Unternehmen. Drei Forschungsströme liefern wichtige Erkenntnisse hinsichtlich der Zusammenarbeit zwischen organisatorischen Gruppen. In diesem Beitrag werden der gegenwärtige Forschungsstand (State-of-the-Art) zu Intergroup Relations, Schnittstellenmanagement und Boundary Spanning zusammengefasst und Massnahmen zur Förderung der Zusammenarbeit zwischen organisatorischen Gruppen abgeleitet. Der Beitrag schliesst mit einer zusammenfassenden Würdigung, in der Unterschiede und Gemeinsamkeiten der Forschungsrichtungen aufgezeigt werden. Darüber hinaus werden wichtige Themen für notwendige weitere Forschung zur Zusammenarbeit zwischen Gruppen skizziert. JEL classifications L20, M10, M12     

生成树协议在局域网中的应用

生成树协议是一种二层管理协议,它通过有选择性地阻塞网络冗余链路来达到消除网络二层环路的目的,同时具备链路的备份功能。生成树协议因为能在局域网中构建无环路的逻辑拓扑结构和提供较强的网络容错功能,而在局域网的可靠性设计中得到广泛应用。论文简要介绍了局域网可靠性设计的思想和生成树协议的工作原理,重点描述了STP在交换机中的实现。     

Estimating demand with distance functions: Parameterization in the primal and dual

Our purpose is to investigate the ability of different parametric forms to ‘correctly’ estimate consumer demands based on distance functions using Monte Carlo methods. Our approach combines economic theory, econometrics and quadratic approximation. We begin by deriving parameterizations for transformed quadratic functions which are linear in parameters and characterized by either homogeneity or which satisfy the translation property. Homogeneity is typical of Shephard distance functions and expenditure functions, whereas translation is characteristic of benefit/shortage or directional distance functions. The functional forms which satisfy these conditions and include both first- and second-order terms are the translog and quadratic forms, respectively. We then derive a primal characterization which is homogeneous and parameterized as translog and a dual model which satisfies the translation property and is specified as quadratic. We assess functional form performance by focusing on empirical violations of the regularity conditions. Our analysis corroborates results from earlier Monte Carlo studies on the production side suggesting that the quadratic form more closely approximates the ‘true’ technology or in our context consumer preferences than the translog.     

On testing for lorenz ordering

Summary A nonparametric asymptotically distribution free approach for testing for Lorenz ordering is presented. Both the one-sample case and the two sample case are considered. This research was supported by an NSERC Canada operating grant at the University of Alberta and Research grant SM065 of Kuwait University.     

Solving higher-dimensional continuous-time stochastic control problems by value function regression

The paper develops a method to solve higher-dimensional stochastic control problems in continuous time. A finite-difference-type approximation scheme is used on a coarse grid of low-discrepancy points, while the value function at intermediate points is obtained by regression. The stability properties of the method are discussed, and applications are given to test problems of up to 10 dimensions. Accurate solutions to these problems can be obtained on a personal computer.     

旅游强县向旅游城市跨越的战略构想——以星子县为例

基于星子县旅游业发展的现状,九江市政府提出要使"星子旅游业由景区建设向旅游城市跨越".这是旅游自身发展规律的内在要求,是地方经济社会发展的现实需要.星子县自然山水与文化元素变相辉映,大规模高品味旅游资源集聚,旅游市场基础好,又处于庐山、鄱阳湖两大旅游区的中心,区位优势十分明显,在江西省努力构建环鄱阳湖生态经济区的政策背景下,星子县具备由旅游强县向旅游城市跨越的可能性.在此基础上,我们针对星子县的实际,提出了实现这一跨越构想的战略对策.     

Asset prices in affine real business cycle models

I describe a tractable way to study macroeconomic quantities and asset prices in a large class of dynamic stochastic general equilibrium models. The proposed approximate solution is analytical, log-linear, and adjusted for risk. Therefore, it is well suited to investigate economic mechanisms, describe the time series properties or estimate the model, and deal with stochastic volatility. I explain the pitfalls encountered by previous attempts to use simple approximation techniques, in particular with models featuring recursive preferences. Finally, I show the theoretical relationship between my solution and higher-order perturbation methods.     

北京市运输业竞争力现状及提升对策

利用进出口数据对北京市运输服务贸易的贸易竞争力指数、比较优势指数和出口优势变差指数进行分析,并将这些指标相互联系和印证,从不同侧面反映北京运输服务贸易的国际竞争力情况;进而从扩大国内运输企业规模效益、提高运输企业技术水平与服务质量、加强运输领域高素质人才培养、健全综合运输服务网络,以及通过运贸一体化把握国际运输主动权等方面,提出提升北京市运输业竞争力的具体对策。     

Momentum strategies with stock index exchange-traded funds

Previously reported momentum profits may not be available to individual investors who have more trading constraints. Therefore, I examine the profitability of momentum strategies with international iShares and US sector exchange-traded funds (ETFs) traded on the NYSE. The index ETFs provide individual investors easy access to international stock markets and US sectors for asset allocations. Using cross-sectional momentum strategies, in contrast to prior research, I find that momentum profits are insignificant for the late 1990s–2014 period. Few country and industry ETFs yield positive results using time series momentum, and the overall performance is worse than the buy-and-hold strategy. Time series momentum offers significant profits during the 2008 global financial crisis, but the profits decline sharply for the post-crisis period.     

Collaborative Knowing: The Adaptive Nature of Cross‐Boundary Spanning

This article elaborates how experts employ boundary objects to perform collaborative work in situ across boundaries. Our study takes a practice lens to examine the adaptive nature of cross‐boundary spanning. We conduct a field study and analyse engineers' troubleshooting tasks in maintaining sophisticated wafer‐fabrication machines. Our findings report three organizing practices: identifying problem boundaries, orchestrating collective responsibilities, and developing a systemic understanding. This mode of organizing explains how experts draw lessons from boundary objects to facilitate adaptive learning and collaboration for solving complicated problems in interactive systems. Our analysis contributes to theories of cross‐boundary spanning, adaptive learning, and problem‐solving, and suggests practical lessons in managing cross‐boundary work.     

System‐Spanning Values Work and Entrepreneurial Growth in Family Firms

Culture and values are key drivers of corporate entrepreneurship in early stages of family firm development, but value conflicts often arise over time that progressively inhibit their entrepreneurial efforts. How can family firms reconcile conflicting values to sustain corporate entrepreneurship over time? Our 45‐year longitudinal case study of a large global family firm shows that family business leaders’ practices of invoking and flexibly using family and business values were crucial to achieve sustained entrepreneurial behaviour and growth over an extended period of time. We theorize these efforts as system‐spanning values work enfolding through specific family, business, and temporal mechanisms. By identifying and elucidating three types of values work (i.e., rooting, revitalizing, and spreading), our study advances current understanding of the micro‐foundations underpinning the relationship between values and entrepreneurship in family firms.     

Risk-neutral skewness and market returns: The role of institutional investor sentiment in the futures market

This paper investigates the effect of index risk-neutral skewness on subsequent market returns and explores whether this effect will vary with various types of institutional investor sentiment in the futures market. Using index futures returns as the proxy of market returns, the empirical results show that the index risk-neutral skewness has a significantly negative effect on subsequent index futures returns. Moreover, the effect of institutional investor sentiment on subsequent index futures returns varies with various types of institutional investor sentiment. Finally, the effect of index risk-neutral skewness on subsequent index futures returns relies on various types of institutional investor sentiment.     

我国沿海省市制造业集聚变动的实证分析

我国沿海省市制造业有明显的产业集聚现象.以新经济地理学模型为基本理论框架,借助产业空间集中程度(SP指数)和绝对集中度(CRn)两项指标,计算1998-2006制造业内部28个行业变化趋势,尝试对我国东部沿海省市制造业近年来的发展状态进行定量评价.结果显示:随着我国东部沿海省市经济的发展,各行业的集中趋势仍是主流,绝大部分行业呈集聚加强趋势,而在区域空间方面出现集聚和衰退两种发展趋势.     

杭州土地市场景气指数构建研究

杭州土地市场是目前我国市场化程度最高的区域土地市场之一,其运行轨迹表现出剧烈的周期性波动。本文的研究目的：对土地市场进行有效的监测预警、为政府利用土地参与宏观调控提供决策支持。研究方法：根据景气指数研究思路,运用合成指数研究方法。研究结果：以杭州土地市场为研究对象,在定性与定量分析相结合的基础上构建了杭州市土地市场景气指数。研究结论：经过半年多的追踪,该指数体系能够较好地评价及预测土地市场发展态势。     

DEA-based Malmquist productivity indexes for understanding courts reform

Currently there is no clear empirical evidence as to which the most appropriate reform to improve national judicial systems might be, i.e., whether it is better to implement a policy which focuses on judges and their incentives or, alternatively, a policy aimed at reorganizing the courts' structure.The judicial system, like many other sectors of the public administration, is an industry producing a specific good – justice – and, accordingly, it can be studied by using the customary tools of production theory. The paper applies the two-stage analysis by Simar and Wilson (2007) and the Malmquist index to the judiciary, in order to better understand the impact of a specific policy on the productivity of the Italian tax judiciary.The results highlight strong heterogeneity among courts, depending on their geographical location, with North-West and North-East of Italy as the most efficient macro areas. Moreover, by decomposing the index into change in efficiency and change in technology, this work provides a further glimpse into the judiciary's production organization. Interestingly, the evidence shows that a reduction in the number of active sections has had a negative impact on the overall performance of the courts (i.e., a negative change in efficiency of 0.0103, with a p-value < 0.01), although the reorganization of the residual sections has possibly determined a more effective use of the remaining resources (i.e., a positive change in technology of 0.00285, with a p-value < 0.01). Hence, technology does not fully replace the productive role of the judges.The overall results suggest that adjudication is a labor-intensive activity and, although fine-tuning their organization can indeed enhance the productivity of the courts, the role of the judges still remains pivotal. There might indeed be ways to increase the efforts made by judges and a suitable policy should create incentives aimed at boosting their productivity.     

Digital Boundary Objects as Negotiation Facilitators: Spanning Boundaries in Virtual Engineering Project Networks

Advances in electronic communication tools have enabled collaborative engineering work to be conducted in virtual project networks that utilize “digital boundary objects” to exchange complex design knowledge. However, little is known about whether and how digital boundary objects facilitate negotiations in virtual settings that feature real‐time communication. This article addresses this gap by exploring the role of digital boundary objects in negotiating complex design knowledge in a three‐dimensional (3‐D) virtual workspace. The authors found that digital boundary objects facilitate negotiations through a three‐stage process of structuring negotiation space, structuring knowledge in the structured negotiation space, and framing combinations of structured knowledge.