Item dwell time in project inventories: A field experiment

This paper describes the use of item dwell-time measurement in the context of capital investment projects. It contributes to the research on product-centric control and intelligent products by empirically demonstrating the value of item dwell-time alerts in the context of project delivery. The paper shows how item dwell-time measurement can be implemented in the field, and compares item dwell-time alerts to conventional measures of inventory turnover and inventory value in four telecommunications infrastructure projects. We find that when individual items cannot be used interchangeably at project sites, conventional inventory measures do not provide sufficiently timely and accurate information about emerging problems in project inventories. These findings are especially important in situations in which supply chain managers can find alternative uses for materials at other sites or in other projects. Timely reallocation of materials prevents the accumulation of slow-moving items that weigh on project performance by increasing obsolescence and inventory holding costs.     

Comparison of machine learning methods for classifying aphasic and non-aphasic speakers

The performance of eight machine learning classifiers were compared with three aphasia related classification problems. The first problem contained naming data of aphasic and non-aphasic speakers tested with the Philadelphia Naming Test. The second problem included the naming data of Alzheimer and vascular disease patients tested with Finnish version of the Boston Naming Test. The third problem included aphasia test data of patients suffering from four different aphasic syndromes tested with the Aachen Aphasia Test. The first two data sets were small. Therefore, the data used in the tests were artificially generated from the original confrontation naming data of 23 and 22 subjects, respectively. The third set contained aphasia test data of 146 aphasic speakers and was used as such in the experiments. With the first and the third data set the classifiers could successfully be used for the task, while the results with the second data set were less encouraging. However, based on the results, no single classifier performed exceptionally well with all data sets, suggesting that the selection of the classifier used for classification of aphasic data should be based on the experiments performed with the data set at hand.     

Discontinuous Petrov–Galerkin method with optimal test functions for thin-body problems in solid mechanics

We study the applicability of the discontinuous Petrov–Galerkin (DPG) variational framework for thin-body problems in structural mechanics. Our numerical approach is based on discontinuous piecewise polynomial finite element spaces for the trial functions and approximate, local computation of the corresponding ‘optimal’ test functions. In the Timoshenko beam problem, the proposed method is shown to provide the best approximation in an energy-type norm which is equivalent to the L₂-norm for all the unknowns, uniformly with respect to the thickness parameter. The same formulation remains valid also for the asymptotic Euler–Bernoulli solution. As another one-dimensional model problem we consider the modelling of the so called basic edge effect in shell deformations. In particular, we derive a special norm for the test space which leads to a robust method in terms of the shell thickness. Finally, we demonstrate how a posteriori error estimator arising directly from the discontinuous variational framework can be utilized to generate an optimal hp-mesh for resolving the boundary layer.     

Event Perception in Mobile Interaction: Toward Better Navigation History Design on Mobile Devices

This article explores how people perceive interactive activities in order to inform navigation history design on mobile devices. Following event segmentation method, 12 participants were asked to break 6 episodes of mobile interaction into segments, organize the segments, and identify those deemed representative. Three findings emerged. First, when making sense of mobile interaction, users concentrate on the content objects on which actions are performed. This indicates the value of content-centric designs in navigation history and other mobile user interface designs. The content objects are data objects and their collections meaningful to the person dealing with it, for example, photos, messages, or albums. Second, users tend to employ two-level hierarchies in grouping segments, and use the similarity in content objects and applications as a reference. They deem the segments as representative where objects are created or changed, or where sharing or querying acts take place. These findings indicate how a navigation history design should organize and prioritize mobile interaction events. Finally, event perception shows relatively low interparticipant consensus, which indicates that navigation history designs have to accommodate large individual differences.     

Activity preserving graph simplification

We study the problem of simplifying a given directed graph by keeping a small subset of its arcs. Our goal is to maintain the connectivity required to explain a set of observed traces of information propagation across the graph. Unlike previous work, we do not make any assumption about an underlying model of information propagation. Instead, we approach the task as a combinatorial problem. We prove that the resulting optimization problem is $\mathbf{NP}$ NP -hard. We show that a standard greedy algorithm performs very well in practice, even though it does not have theoretical guarantees. Additionally, if the activity traces have a tree structure, we show that the objective function is supermodular, and experimentally verify that the approach for size-constrained submodular minimization recently proposed by Nagano et al. (28th International Conference on Machine Learning, 2011) produces very good results. Moreover, when applied to the task of reconstructing an unobserved graph, our methods perform comparably to a state-of-the-art algorithm devised specifically for this task.     

Third Particle Ejection Effects on Wear with Quenched and Tempered Steel Fretting Contact

The design and life prediction of fretting wear-sensitive mechanical components remain a challenge. In the present work, the role of wear particle movements under conditions of axisymmetric loading of an annular flat-on-flat contact were investigated using self-mated quenched and tempered steel specimens. Total fretting wear significantly increased when loose wear particles were periodically removed from the interface, and this effect increased as a function of the sliding amplitude. Additionally, increased wear was measured when grooves perpendicular to the sliding direction were added to the interface. Increasing the rate of wear debris ejection leads to increased wear rate because naturally occurring entrapped third-body particles significantly reduce the wear. The shape of fretting loops and values of the average and maximum coefficient of friction remained unaffected by the removal of entrapped wear debris and by the introduction of the grooves.     

Embodied interaction with a 3D versus 2D mobile map

In comparison to 2D maps, 3D mobile maps involve volumetric instead of flat representation of space, realistic instead of symbolic representation of objects, more variable views that are directional and bound to a first-person perspective, more degrees of freedom in movement, and dynamically changing object details. We conducted a field experiment to understand the influence of these qualities on a mobile spatial task where buildings shown on the map were to be localized in the real world. The representational differences were reflected in how often users interact with the physical environment and in when they are more likely to physically turn and move the device, instead of using virtual commands. 2D maps direct users into using reliable and ubiquitous environmental cues like street names and crossings, and 2D better affords the use of pre-knowledge and bodily action to reduce cognitive workload. Both acclaimed virtues of 3D mobile maps—rapid identification of objects and ego-centric alignment—worked poorly due reasons we discuss. However, with practice, some 3D users learned to shift to 2D-like strategies and could thereby improve performance. We conclude with a discussion of how representational differences in mobile maps affect strategies of embodied interaction. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Remote sensing of climate change,long-term monitoring of air pollution and stone material corrosion in Estonia

The Fifth National Communication Under the Framework Convention on Climate Change covered the policies and activities in Estonia of the period 2006–2009. Climate change and air pollution cause significant damage, especially to various materials. Worldwide, 387 objects belong to the United Nations Educational, Scientific and Cultural Organization (UNESCO) World heritage list, including the Old Town of Tallinn. The International Cooperative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) is an ongoing research programme in the framework of which air pollution and the effect of climate on the corrosion of various natural and synthetic materials, including historical and cultural monuments, is studied. So far, the studies have shown that even though air pollution has continuously declined in Estonia, no significant reduction in corrosion has been noticed on the displayed limestone sample plates at the Lahemaa air monitoring station. On the contrary, in 2005–2006, the corrosion loss of limestone was greater compared with that in 1987–2003. It could be explained partly by changing environmental conditions but another possible explanation is that the Portland limestone as a stone material has a different quality.     

The flow resistance of fiber sheet during initial dewatering

In this work, a novel experimental filtration device with pressure profiling was used for analyzing water removal from the fiber network in the forming section of a paper machine. The experimental data were used to develop a stratified model for the flow resistance of the developing fiber sheet during the filtration process. The new model was verified with both laboratory- and pilot-scale measurements and excellent agreement was observed between them. It was also observed that there is a strong linear correlation between the maximal attainable solid content of a filtered sheet after the forming section and the instantaneous response to pressure of the flow resistivity of the furnish.     

Controlling Testing Using Three-Tier Model Architecture

In this paper, based on our earlier work, we introduce test model architecture for model-based testing through a GUI. The model architecture consists of three tiers. The tiers separate important concerns in GUI testing: navigation in the GUI using keywords, high-level concepts expressed as action words, and test-control related issues defined as control words. For test control, we define a novel coverage language to express coverage objectives. Furthermore, we introduce our refined vision for the associated tool platform enabling system level testing in the Symbian environment. The architecture includes a commercial GUI testing tool that we have extended with components enabling the use of test models.