Life-cycle funds: Much Ado about Nothing?

The core idea of life-cycle funds or target-date funds is to decrease the fund's equity exposure and conversely increase its bond exposure towards the fund's target date. Such funds have been gaining significant market share and were recently set as default choice of asset allocation in numerous defined contribution schemes or related old-age provision products in several countries. Hence, an assessment of life-cycle funds’ risk-return profiles – that is, the probability distribution of returns – is essential for sustainable financial planning of a large group of investors. This paper studies the risk-return profile of life-cycle funds in particular compared to simple balanced or lifestyle funds that apply a constant equity portion throughout the fund's term instead. In a Black–Scholes model, we derive balanced funds that reproduce the risk-return profile of an arbitrary life-cycle fund for single and regular contributions. We then analyze the accuracy of our results under more complex asset models with stochastic interest rates, stochastic equity volatility and jumps. We further show that frequently used ‘rule of thumb approximations’ that only take into account the life-cycle fund's average equity portion are not suitable to approximate a life-cycle fund's risk-return profile. Our results on the one hand facilitate sustainable financial planning and on the other hand challenge the very existence of life-cycle funds since appropriately calibrated balanced funds can offer a similar (often dominating) risk-return profile.     

Optimizing station location and fleet composition for a high-speed rail line

This paper proposes a new strategic planning model for high-speed rail ventures. It is a mixed-integer optimization model that applies to a given line and focuses on two key strategic decisions: station location and fleet composition. Our purpose is to improve on previous station location models by including fleet composition decisions. In the new model, we additionally take into account in an approximate fashion the interrelationships between strategic and subsequent tactical decisions, regarding line planning, train scheduling and fleet assignment issues. The usefulness of the model is demonstrated for a case study involving a planned Lisbon-Oporto high-speed rail line.     

Runway capacity management – An empirical study with application to Doha International Airport

This paper examines a three-faceted approach for runway capacity management, based on the runway configuration, a chosen scheduling approach, and an aircraft separation standard. These factors prompt alternative runway settings that are encapsulated using a classical mixed-integer formulation. The optimal solution for each runway setting is compared against our proposed optimization-based heuristic. This integrated approach is applied to investigating the transition from the (Old) Doha International Airport to the New Doha International Airport. Our empirical study based on historical data reveals that the proposed heuristic consistently yields optimal or near-optimal schedules, with considerable savings in fuel cost and reductions in delays, while preserving the spirit of an FCFS sequencing policy.     

A Qualitative Study for Measuring Warehouse Performance Using Triangulation Approach

This research aims to validate a structural equation modeling （SEM） model for measuring warehouse performance using data from an international company in Australia （company G）. Moreover, a methodological triangulation method was also adopted to test whether different methodological approaches produce convergent findings about warehouse performance measurement （WPM）. These three different methods are the SEM model, the multiple case research study, and validation of the SEM model using data from 80 companies in Thailand and a company in Australia. With the results from the triangulation method, it is obvious that the SEM model can be used to measure the performance of warehouses in Thailand and Australia. Since the SEM model consists only of significant indicators, it is more appropriate than company G＇s scorecard. Furthermore, the SEM model can overcome the limitations of traditional models by allowing companies to compare their performance over time.     

Neighborhood Effects and Regional Poverty Traps in Rural China

The present paper investigates how neighborhood effects are connected to chronic poverty. We examine a large sample of groups of households and find that neighborhood effects are significant in a majority of groups, especially in the poorest groups. People living in poor communities tend to suffer from poverty over time. It is of theoretical and empirical importance to explore how neighborhood effects are interrelated with chronic poverty and the channels through which this occurs. Unlike other econometric analyses, we establish a multilevel econometric model to show that： （i） it is difficult for an individual living in a neighborhood with a high proportion of agricultural labor, low education levels, and poor transport and telecommunication infrastructure to escape from poverty traps; （ii） neighborhood effects dominate in poor communities; and （iii） although poverty is affected by group-level factors, individual factors still play a dominant role in regards to escaping poverty when income surpasses a threshold level Therefore, policy priority should be given to providing social protection and public services, especially in poor rural areas.     

中原地区民间服饰刺绣的艺术风格研究

通过对中原地区民间刺绣的色彩、造型艺术和工艺技法的深入研究,展现了民间刺绣独特的色彩应用理论,夸张多变的造型和工艺上独到的艺术风格,为民间刺绣的现代应用指明方向。     

基于UG的螺旋桨逆向建模

文章对螺旋桨的一般设计过程和基于UG的建模功能,以及对已有的螺旋桨进行逆向建模的整个过程进行了系统介绍。     

浅谈公路工程项目施工网络图的优化

文章针对传统的公路施工网络图优化中存在的问题和不足,运用启发式搜索算法和遗传算法,对公路施工网络优化从时间、费用、资源三方面进行网络计划的优化和调整。     

浅析中国传统建筑的空间与造型

中国人自古以来过着修身养性的生活,人们依赖自然,亲和自然。中国传统建筑主张"天人合一"。基于与自然高度协同的中国文化精神,热爱自然、尊重自然,镶嵌在自然中,仿佛是大自然的一个有机组成。这不仅在中国各建筑类型中有明显的反映,在与自然高度协同的观念在园林中更有突出的表现。这种朴素的哲学思想影响着中国古典建筑室内外空间塑造。本文仅从古建筑的空间处理和建筑的造型两个方面分析一下中国传统建筑的可持续发展性。     

纸张复卷机的设计造型与仿真

本论文介绍了下引纸复卷机的方案,针对关键部件底辊进行了设计计算,用UG软件完成了整机三维造型,并结合3DSMAX实现了复卷过程的仿真。