Exploring the roles of portfolio steering committees in project portfolio governance

Governing project portfolios engages different actors in organizations including portfolio managers, portfolio officers, top managers, and others who may team up as portfolio steering committees. While portfolio steering committees play a regular role in project portfolio governance, their role is still unclear. Through an in-depth multiple case study in three Danish companies, the roles of portfolio steering committees were explored. The results showed that portfolio committees may play three distinct roles in portfolio governance: a) communication and consolidation role, b) negotiation role, and c) decision making role. The results challenged the notion that portfolio committee meetings are the place and time to make collective decisions on the portfolio, rather, portfolio steering committees might unintentionally become or intentionally be used for other purposes than decision making. The empirical evidence of the study proposes that these three roles might be related to two governance design factors: frequency and duration of committee meetings.     

Hard-rock LHD cost estimation using single and multiple regressions based on principal component analysis

In feasibility studies and mine planning, accurate and effective tools and methods facilitating cost estimation play an important role. Load-Haul-Dump (LHD) machines are a key loading and haulage equipment in most of the underground metal mines and hard rock tunnels. In this paper, a cost estimation model of these vehicles has been presented in the form of single and multivariable functions. These functions have been provided on the basis of costs types (i.e. capital and operating costs) and motor types (diesel and electric). Independent variables, in the single regression analysis is bucket capacity and in Multiple Linear Regression (MLR) analysis include bucket capacity, overall width, overall machine height and horse power (HP). The MLR is conducted in three steps. First, with the help of Principal Component Analysis (PCA), correlation between independent variables is omitted. Thereafter, significant PCs are selected and used as independent variables in the MLR functions. Finally, the cost relationships are established as functions of initial LHD variables. The mean absolute error rates are 11.59% and 6.87% for the single and multiple linear regression functions, respectively.     

International immigration and domestic out-migrants: are domestic migrants moving to new jobs or away from immigrants?

Domestic migrant responses to geographically concentrated immigration flows play central roles in determining the local economic impacts of immigration and the geography of the ethnic composition of the population. Possible motivations for domestic migrant responses include: increased labor market competition associated with new immigrants and ethnic or cultural avoidance. We use US annual state-to-state migration flows from the Internal Revenue Service to assess the existence and nature of the link between geographically concentrated immigration and domestic migration. We find some evidence of a domestic migrant response to immigrants, particularly to greater cumulative shares of the foreign born, which we interpret as providing some support of the ethnic or cultural avoidance hypothesis.     

The effects of the COD:P ratio on laboratory activated sludge systems

Laboratory activated sludge systems were operated at various COD:P ratios to study the effects of the influent phosphorus concentration on COD removal efficiency, cellular phosphorus, carbohydrate and protein contents, and alkaline phosphatase activity. In varying the COD:P ratio, the COD was held constant at 1000 mg l⁻¹ and phosphorus concentrations of 1, 2, 3, 5, 7, 9, 10, 20, 35 and 50 mg l⁻¹ were used. The optimum COD:P ratio for this study was found to be 100:1. Increasing the phosphorus concentration in the influent above one percent of the influent COD did not provide for an increase in the COD removal nor for significant changes in the cellular protein and carbohydrate content or the alkaline phosphatase activity.     

Influence of joint detail on the flexural/torsional interaction of thin-walled structures

For a structure formed from two thin-walled open members connected at 90°, torsion applied to one member can result in torsion as well as flexure in the second member, with the magnitude and direction of this torsion as well as flexure in the second member being determined by the type of joint used. Conventional structural analysis would normally assume the presence of only flexure in the second member. The results from a finite element study of structures formed from thin-walled channel sections connected by box, mitre and stiffened mitre joints is presented and an explanation for the behaviour of the different joint types is given. It is shown that for the box joint the warping deformation of the loaded member is the dominant factor in determining the magnitude and direction of the twisting of the second member, whilst this is determined for the stiffened mitre joint primarily by the St Venant rotation deformation of the loaded member. For the unstiffened joint it is shown that the warping and St Venant rotation deformation effects tend to cancel each other out.     

变荷载作用下未打穿竖井地基固结分析

利用已有瞬时荷载作用下未打穿竖井地基固结模型,根据线性偏微分方程的叠加原理,将变荷载作用问题分解为瞬时荷载作用问题,给出了变荷载作用下未打穿竖井地基固结解答。利用该求解方法,对一未打穿竖井地基在单级线性加载和多级加载情况下的孔压消散进行了分析。分析表明,受加载历时影响,竖井打设区平均固结度减小幅度大于下卧层,但下卧层受影响时间要长得多。另外,在粗略设计中,可以将多级加载简化为单级线性加载,这样对后期平均固结度的影响不大。     

Cu, Cr and As distribution in soils adjacent to CCA-treated utility poles in Eastern Blacksea Region of Turkey

In this study, the main objective was to asses the distribution of Cu, Cr, and As in soils adjacent to CCA-treated utility poles in Eastern Blacksea Region of Turkey (Trabzon, Rize and Artvin ) and determine the influence of soil composition.

Surface (0–5 cm) and subsurface soil samples (30–40 cm) were collected near CCA-treated utility poles and control soil samples away from CCA-treated utility poles were also collected. Water holding capacity, pH and mechanical properties of soil samples were determined for both depth levels.

Results showed that Cu, Cr and As concentration in soil samples taken from all three cities in 0–5 cm depth was higher than soil samples taken from 30–40 cm depth. Cu, Cr and As concentrations were much higher in soil samples taken from city of Rize     

On the effect of large deflection on nonlinear behavior of an eccentric bracing system

In this article, a particular off‐center bracing system is introduced. In this system, the tensile diagonal strut is not straight. When the load is applied, the original geometry changes and thus causes the system to harden. Based on this behavior, a step‐by‐step analytical method is developed. Using this method, a Geometrically Nonlinear Analysis Program (GNAP) is designed to analyze the elastic force–displacement relation. Extension of this program to dynamic analysis led to a Dynamic Nonlinear Analysis Program (DNAP). The object of this article is to show that such bracing systems will lead to less seismic force on such structures compared to classic concentric bracing systems. On the other hand, it will be shown that the bracing system causes semi‐uncoupling of structure, and that the probable excursions in the nonlinear range during severe earthquakes will not cause significant deterioration in its strength and stiffness. Copyright © 2007 John Wiley & Sons, Ltd.     

Patterns of exits from housing in a homelessness system of care: the case of Calgary,Alberta

Public officials around the world seek to target subsidized housing as purposely and efficiently as possible. With limited availability of subsidized housing, it is helpful to know which household types require specific types of housing support and for how long. With this in mind, we undertake survival analysis and hazard models on clients placed into housing funded by the Calgary Homeless Foundation (CHF) to characterize patterns of exit from Calgary’s homeless system of care. To do this, we use data from Calgary’s Homelessness Management Information System from 1 April 2012 until 31 March 2015. We find singles without dependents to require housing support for the longest period of time, while families require the support for the least amount of time. One important finding is that women require housing support for longer periods of time than men (even though we control for employment and income).