The European port industry: an analysis of its economic efficiency

Because of their critical strategic role, ports have all traditionally been subject to some form of government control even if the legal form and the intensity of this control have varied across countries. The member countries of the European Union have not been different from the rest of the world in this respect. A significant difference however is the recurrent effort to integrate, in a coordinated way, the port sector in a trans-European transport network (TEN-T) through the adoption of a common legal framework. In this context, if the objective of the reforms is to ensure that port networks, integrated in combined transport networks, become competitors of the road network, the concept of port efficiency becomes central. This paper provides an overview of the evolution of the European Port Legislation and shows how comparative economic measures can be used to highlight the scope for port efficiency improvements, essential to allow short sea shipping transport to compete with road transport in Europe. To our knowledge, this paper is also the first effort of estimating technical efficiency of European Port Authorities. The average port efficiency in 2002 was estimated to be around 60%, denoting that ports could have handled 40% more traffic with the same resources. Maritime Economics & Logistics (2007) 9, 148â171. doi:10.1057/palgrave.mel.910017

Quantifying Changes in Creativity: Findings from an Engineering Course on the Design of Complex and Origami Structures

Engineering educators have increasingly sought strategies for integrating the arts into their curricula. The primary objective of this integration varies, but one common objective is to improve students’ creative thinking skills. In this paper, we sought to quantify changes in student creativity that resulted from participation in a mechanical engineering course targeted at integrating engineering, technology, and the arts. The course was team taught by instructors from mechanical engineering and art. The art instructor introduced origami principles and techniques as a means for students to optimize engineering structures. Through a course project, engineering student teams interacted with art students to perform structural analysis on an origami-based art installation, which was the capstone project of the art instructor’s undergraduate origami course. Three engineering student teams extended this course project to collaborate with the art students in the final design and physical installation. To evaluate changes in student creativity, we used two instruments: a revised version of the Reisman Diagnostic Creativity Assessment (RDCA) and the Innovative Behavior Scales. Initially, the survey contained 12 constructs, but three were removed due to poor internal consistency reliability: Extrinsic Motivation; Intrinsic Motivation; and Tolerance of Ambiguity. The nine remaining constructs used for comparison herein included: • Originality: Confidence in developing original, innovative ideas • Ideation: Confidence in generating many ideas • Risk Taking: Adventurous; Brave • Openness of Process: Engaging various potentialities and resisting closure • Iterative Processing: Willingness to iterate on one’s solution • Questioning: Tendency to ask lots of questions • Experimenting/exploring: Tendency to physically or mentally take things apart • Idea networking: Tendency to engage with diverse others in communicative acts • Observing: Tendency to observe the surrounding world By conducting a series of paired t-tests to ascertain if pre and post-course responses were significantly different on the above constructs, we found five significant changes. In order of significance, these included Idea Networking; Questioning; Observing; Originality; and Ideation. To help explain these findings, and to identify how this course may be improved in subsequent offerings, the discussion includes the triangulation of these findings in light of teaching observations, responses from a mid-semester student focus group session, and informal faculty reflections. We close with questions that we and others ought to address as we strive to integrate engineering, technology, and the arts. We hope that these findings and discussion will guide other scholars and instructors as they explore the impact of art on engineering design learning, and as they seek to evaluate student creativity resulting from courses with similar aims

Convergence analysis of hybrid cellular automata for topology optimization

The hybrid cellular automaton (HCA) algorithm was inspired by the structural adaptation of bones to their ever changing mechanical environment. This methodology has been shown to be an effective topology synthesis tool. In previous work, it has been observed that the convergence of the HCA methodology is affected by parameters of the algorithm. As a result, questions have been raised regarding the conditions by which HCA converges to an optimal design. The objective of this investigation is to examine the conditions that guarantee convergence to a Karush-Kuhn-Tucker (KKT) point. In this paper, it is shown that the HCA algorithm is a fixed point iterative scheme and the previously reported KKT optimality conditions are corrected. To demonstrate the convergence properties of the HCA algorithm, a simple cantilevered beam example is utilized. Plots of the spectral radius for projections of the design space are used to show regions of guaranteed convergence

Evolution of Magnetism in Single-Crystal Honeycomb Iridates

We report the successful synthesis of single-crystals of the layered iridate, (Na$_{1-x}$Li$_{x}$)$_2$IrO$_3$, $0\leq x \leq 0.9$, and a thorough study of its structural, magnetic, thermal and transport properties. The new compound allows a controlled interpolation between Na$_2$IrO$_3$ and Li$_2$IrO$_3$, while maintaing the novel quantum magnetism of the honeycomb Ir$^{4+}$ planes. The measured phase diagram demonstrates a dramatic suppression of the N\'eel temperature, $T_N$, at intermediate $x$ suggesting that the magnetic order in Na$_2$IrO$_3$ and Li$_2$IrO$_3$ are distinct, and that at $x\approx 0.7$, the compound is close to a magnetically disordered phase that has been sought after in Na$_2$IrO$_3$ and Li$_2$IrO$_3$. By analyzing our magnetic data with a simple theoretical model we also show that the trigonal splitting, on the Ir$^{4+}$ ions changes sign from Na$_2$IrO$_3$ and Li$_2$IrO$_3$, and the honeycomb iridates are in the strong spin-orbit coupling regime, controlled by \jeff=1/2 moments.Comment: updated version with more dat

KKT conditions satisfied using adaptive neighboring in hybrid cellular automata for topology optimization

The hybrid cellular automaton (HCA) method is a biologically inspired algorithm capable of topology synthesis that was developed to simulate the behavior of the bone functional adaptation process. In this algorithm, the design domain is divided into cells with some communication property among neighbors. Local evolutionary rules, obtained from classical control theory, iteratively establish the value of the design variables in order to minimize the local error between a field variable and a corresponding target value. Karush-Kuhn-Tucker (KKT) optimality conditions have been derived to determine the expression for the field variable and its target. While averaging techniques mimicking intercellular communication have been used to mitigate numerical instabilities such as checkerboard patterns and mesh dependency, some questions have been raised whether KKT conditions are fully satisfied in the final topologies. Furthermore, the averaging procedure might result in cancellation or attenuation of the error between the field variable and its target. Several examples are presented showing that HCA converges to different final designs for different neighborhood configurations or averaging schemes. Although it has been claimed that these final designs are optimal, this might not be true in a precise mathematical sense—the use of the averaging procedure induces a mathematical incorrectness that has to be addressed. In this work, a new adaptive neighboring scheme will be employed that utilizes a weighting function for the influence of a cell’s neighbors that decreases to zero over time. When the weighting function reaches zero, the algorithm satisfies the aforementioned optimality criterion. Thus, the HCA algorithm will retain the benefits that result from utilizing neighborhood information, as well as obtain an optimal solution

Sleep Duration Mediates the Relationship Between Health Behavior Patterns and Obesity

Objective: To examine associations between health behavior patterns and childhood obesity, and the mediating effect of sleep duration. Design: Population-based survey. Participants: Secondary analysis of data from the Infant Feeding Practices Study (age 6 years, n = 1073). Measurements: Mothers self-reported their child’s health behaviors including physical activity (PA), screen time, sleep duration, and diet. Latent class analysis determined the child’s patterns based on health behaviors. Sleep was examined as a mediator between the class membership variable and %BMIp95. Results: A 3-class model fit the data best, with classes labeled as “Poorest eaters” (low fruit/vegetable consumption, high fast food), “Healthy” (low screen time, highest fruit/vegetable consumption) and “Active, super-eaters, highest screen time” (highest PA and screen time, ate the most). “Poorest eaters” had an increased %BMIp95 (β = 4.11, P = .006) relative to the “Healthy” class. The “Poorest eaters” and “Active, super-eaters, highest screen time” classes had shorter sleep duration (β = −0.51, P \u3c .001; β = −0.38, P \u3c .001; respectively) relative to the “Healthy” class. Independent of class membership, each additional hour of sleep was associated with a %BMIp95 that was 2.93 U lower (P \u3c .001). Conclusions: Our results indicate that health behavior patterns mediated by sleep duration may influence a child’s %BMIp95. The bi-directionality of the relationship between health behaviors and sleep remains unclear. Our findings suggest the importance of a constellation of health behaviors on childhood obesity. Interventions should include a multitude of health behaviors and consider the possibility that improving diet and activity behaviors may facilitate improved sleep and lowered obesity risk among children