Towards a contingent approach of customer involvement in defence projects: An exploratory study

This paper reports the main results of an exploratory, multiple case study investigating customer involvement practices in system development projects in the Israeli defence industry. The study proposes and examines a theoretical contingency model regarding the effect of customer involvement modes on project success, moderated by project characteristics. It focuses specifically on the working mode of customers' representatives along the continuum between external supervision to full participation in project activities.     

Three-dimensional numerical modeling of single geocell-reinforced sand

This paper summarizes the development of a three-dimensional numerical model for analyzing single geocell-reinforced soil. In this model, the infill soil was modeled using the Duncan-Chang model, which can simulate non-linearity and stress-dependency of soil. Geocell was modeled using linearly elastic plate elements, which can carry both bending and membrane stresses. A linear interface stress-strain relationship with a Mohr-Coulomb yield criterion was adopted to model the interface friction between the geocell wall and the soil. By modeling the geocell and the soil separately, the interaction between the soil and the geocell can be accurately simulated. To verify this model, a plate load test was conducted in the laboratory, in which a 12-cm-thick sand layer reinforced by a single geocell was subjected to a vertical load from a circular steel plate. The load-displacement curves and the horizontal tensile strain of the geocell were recorded during the test. A numerical model was created according to the setup of the load test. The numerical results compared reasonably well with the test data.     

Mechanically stabilized walls over soft clay: Geosynthetic to prevent deep-seated failures

Mechanically stabilized walls can sometimes be economically constructed over poor foundations such as a soft clay. A major design concern in such a case, however, is the stability against deep-seated failure where the potential slip surface passes through the unreinforced backfill and the clayey foundation. To attain a prescribed safety margin against deep-seated instability, a high-strength geosynthetic sheet, placed at the backfill-clay interface, can be used. The objective of this paper is to present an analysis method which enables the user to determine the required distribution of tensile resistance of the reinforcing sheet and therefore can be used as a design tool. The analysis is based on limit-equilibrium and by virtue of the mechanism used it is rigorous in the sense that no statical assumptions are utilized. Its predictions compare favorably with some conventional methods; its application, however, is easier. It is demonstrated how the analysis results can be condensed into a useful format of design charts. Since the direction of the reinforcement's tensile resistance is not known, a zone is suggested within which is the probably required distribution of this force.     

Precarious manhood.

The authors report 5 studies that demonstrate that manhood, in contrast to womanhood, is seen as a precarious state requiring continual social proof and validation. Because of this precariousness, they argue that men feel especially threatened by challenges to their masculinity. Certain male-typed behaviors, such as physical aggression, may result from this anxiety. Studies 1-3 document a robust belief in (a) the precarious nature of manhood relative to womanhood and (b) the idea that manhood is defined more by social proof than by biological markers. Study 4 demonstrates that when the precarious nature of manhood is made salient through feedback indicating gender-atypical performance, men experience heightened feelings of threat, whereas similar negative gender feedback has no effect on women. Study 5 suggests that threatening manhood (but not womanhood) activates physically aggressive thoughts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quality approach for multi-parametric data fusion

Data fusion has gained widespread use in different areas of measurement in the last years, mainly where the sought output of an analysis cannot be measured directly—medical imaging, non-destructive testing, remote sensing, etc. The process of data fusion as such is not characterized today by any quality characteristics, which makes it impossible to estimate the effectiveness and reliability of the fused data. The authors propose a new approach to the process, free of this drawback. The introduced term of relevant information, with allowance for the first- and second-kind errors and their corresponding penalties, allows application of the Taguchi methodology via the loss function. The presented information scale, with the data-fusion types classified according to the information volume, ensures effectiveness of the planned process. The proposed approach is illustrated in examples of application.     

Species composition and plant traits: Characterization of the biogeomorphological succession within contrasting river corridors

Plant communities and dynamics can be characterized according to species composition or plant traits. Here, we used species composition and plant traits to compare their effectiveness in discriminating the biogeomorphological (involving reciprocal feedbacks between physical and biological processes) and ecological (mainly biologically driven) phases of the fluvial biogeomorphological succession (FBS) model. The comparison was done between two French rivers, the largely unchannelized lower Allier and the channelized middle Garonne. One reach representative of each river section was selected for the study. Within each river reach, we chose two contrasted study sites in terms of channel and floodplain dynamics: a reference site (least altered channel and floodplain dynamics) and an altered site (laterally stabilized by riprap and constrained). In the four study sites, we sampled vegetation in 402 plots of 4 m². The 512 species identified in the plots were characterized in terms of plant traits (20) from a literature review. When comparing reaches in unconstrained ordinations and permutational multivariate analyses of variance, both species composition and plant traits led to a similar identification of the biogeomorphological and the ecological successional trajectories. Nevertheless, the trait approach was less influenced by local and regional bioclimatic, hydrogeomorphological, and anthropogenic settings and thus produced a more comprehensive and general classification of the biogeomorphological and ecological phases of the FBS model. A lower than expected contrast between the four sites was found, because neither species composition nor plant traits could entirely characterize distinct successional trajectories occurring in our reference or altered sites. Furthermore, our results contributed to a better understanding of the multiple successional trajectories that can occur in midlatitude river corridors. It also showed that relating plant traits to their effects on fluvial landform dynamics remains a core challenge in explaining succession including feedback mechanisms between hydrology, morphodynamics, and vegetation dynamics.     

Work-input model for assembly and disassembly of high shoring towers

High shoring towers, the common shoring solution for high clearance construction, cause the entire formwork system to account for a remarkably high percentage of the cost of the constructed concrete element. However, data on work inputs in assembly and disassembly of high towers are scarce, and the reason lies in the difficulty in conducting the numerous work studies that would be needed to cover the wide variety of tower types offered by the market and the extensive range of heights to which towers are erected. A model is presented, based on a limited number of work studies, for the prediction of work inputs in the assembly and disassembly of shoring towers of two configurations, rising to heights of up to 30 m. Results of actual measured work input data for three tower models representing three tower types widely used on construction sites are presented. An insight is provided into the anatomy of tower erection, which should make possible use of the proposed methodology for the development of similar models for additional tower types.     

Limited reinforced space in segmental retaining walls

Current design of geosynthetic reinforced segmental retaining walls considers an a priori limitless length for reinforcement installation. Such length is typically 0.5–0.7 times the height of the wall. However, often there are constraints on such space; e.g., bedrock formation located at a small distance behind the facing. The objective of this note is to introduce a procedure for assessing the required long-term strength of the reinforcement while considering its limited length. Predictions by a conventional slope stability analysis were first checked against a continuum-mechanics based numerical analysis. Upon obtaining good agreement, a design chart was developed. The chart enables the determination of the reduction in the lateral earth pressure coefficient due to the constrained space. The revised earth pressure coefficient can be used with current analytical methods to account for the limited space. The results appear to be valid for conventional walls retaining a limited volume of soil. Comparison with limited experimental results for unreinforced backfill shows reasonably good agreement.