178 research outputs found
An Examination of the Globalisation of Authorship in Publishing in 20 Leading Marketing Journals
No full textPurpose of this paper is to examine the global contribution of academics to marketing literature between 1999 and 2003, based on an examination of the location of academics institution of employment, as reported in published works. The data is used to evaluate the global dispersion of publishing.\ud
Design/approach. The paper uses the method of content analysis where the authorship of all articles in 20 leading marketing journals between 1999 and 2003 is examined. An empirical examination of performance was undertaken across geographic regions. There was also an examination of whether the quality of journal affected regional performance.\ud
Findings. The research found that there is a significant "bias" of authorship within the 20 journals examined, with the majority of works published by academics at institutions in North America. There is some variation in regional performance based on the type of journal examined. Limitations. There was no attempt to empirically examine why differences might exist. The study only focused on a sample of 20 English language journals over 5 years. These journals have been included in studies that list the leading marketing journal for US and European academics. Practical Implications. The research suggests that there may in fact be regional differences in publishing behaviour. It is unclear if these differences relate to variations in the "objectives" of institutions within each country or other factors, such as the North American publish-or-perish mentality. The research posits that a marketing knowledge may be unnecessarily restricted, if there is a bias against non-North American perspectives. Originality. While there have been other works examining research performance of institutions, there has been limited examination in marketing on the nation in which authors work and none have used a broad cross-section of journals. This work takes a global "snapshot" of national research performance within marketing
Sensor management for surveillance and tracking: An operational perspective
No full textRadars have gained increased popularity as sensing devices due to their unique capability to sense objects of interest at very long distances and without being severely limited by weather conditions. Advances in technology have led to the possibility of choosing the sensing parameters of a radar in order to further improve its performance. Especially in the class of active phased array radars, the control of the agile beam is of paramount importance. By controlling the radar beam improved estimation results can be achieved leading to better situation awareness. In the literature, several approaches to sensor (including radar) management can be found. These can be roughly grouped into: a) rule-based or heuristics; b) task-based; c) information-driven; and d) risk/threat-based. These approaches are compared in this thesis and it is found that there is not a single approach that is both Bayes-optimal and takes into account explicitly the user requirements in different operational contexts. In order to overcome the challenges with the existing approaches, this thesis proposes managing the uncertainty in higher-level quantities (as per the JDL model) that are directly of interest to the operator and directly related to the operational goal of the radar system. The proposed approach is motivated by the threat assessment process, which is an integral part of defence missions. Accordingly, a prominent example of a commonly used higher-level quantity is the threat-level of a target. The key advantage of the proposed approach is that it results in Bayes-optimal sensor control that also takes into account the operational context in a model-based manner. In other words: a) a radar operator can select the aspects of threat that are relevant to the operational context at hand; and b) external information about the arrival of targets and other scenario parameters can be included when defining the models used in the signal processing algorithms, leading to context-adaptive sensor management. The proposed approach is initially used in simple tracking examples in order to demonstrate its potential and flexibility. Subsequently, it is used for controlling an agile radar beam such that multiple targets can be tracked while taking into account detection uncertainty and presence of spurious measurements. In these examples, a state-of-the art signal processing algorithm is used, i.e. a CB-MeMBer filter. Finally, the proposed approach is used for area surveillance, i.e. for detection and tracking of multiple targets while taking into account detection uncertainty and presence of spurious measurements. In this context, a density that estimates where any undetected targets might be (denoted as unDTD) plays a key role in balancing the search-to-track time ratio. The presented examples have been drawn both from the civilian and the military domain. From the civilian domain, air-traffic-control examples are shown where threat is modeled based on how fast and how close to each other two aircrafts might come. From the defence domain, asset protection examples are shown where threat is modeled based on how fast and how close to an asset of interest a target might come. Furthermore, the deviation from expected trajectories has been modeled because it can be of interest for anomaly detection purposes. The proposed approach has outperformed all the other approaches in the simulated examples presented in this thesis in achieving lower uncertainty in the threat-level of all targets. In all examples, the proposed approach has outperformed naïve approaches, such as periodic or random selection of sensing actions, in a) estimating the correct number of targets present in the considered scenarios; b) localizing the detected targets; and c) maintaining less tracks, thus lowering the computation time at the update step. When only tracking of targets is considered, the proposed approach was only outperformed in tracking accuracy by a scheme that minimizes the expected variance of the estimated number of targets present in the considered scenario and by a derived rule-based scheme. The main challenge when implementing the proposed approach is the mathematical description of threat. Several interesting aspects of threat have been modeled in this thesis but there are even more to be modeled. Taking into account non-measurable aspects of threat poses an added challenge. Other challenges that might be encountered are a) lower tracking accuracy; and b) higher computational complexity, when compared to other sensor management schemes. The presented research can be extended both within the radar domain and by exploring its application to other domains. Two prominent extensions of interest within the radar domain are: a) taking more aspects of threat into account; and b) addressing the target classification problem. Robotics applications, such as autonomous robot path-planning, offer a promising alternative domain for applying the proposed method.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
Feeling Uncertain: Effects of Encoding Uncertainty in the Tactile Communication of a Spatiotemporal Feature
No full textAn appropriate understanding of a machine's competences may be critical for safe use. Sharing measures of real-time function reliability could help users to adjust their reliance on machine capabilities. We designed a vibrotactile interface that communicates spatiotemporal information about surrounding events and further encodes a representation of spatial uncertainty. We evaluated this interface in a driving simulator experiment with varying levels of machine confidence linked to a simulated degradation of sensor signal quality and varying levels of human confidence induced through a degradation of visual feedback. A comparison between variants of the system indicated positive performance effects of providing uncertain information compared to a more conservative solution that only provided information above a specific confidence level. Subjective reports revealed a positive acceptance of uncertainty signaling in low-visibility conditions, comparable to acceptance ratings of a fully confident machine that accurately signaled the precise location of events.Digital supplement is available at www.github.com/tomdries/feelinguncertainMechanical Engineerin
Comparative efficacy of interpersonal psychotherapy and antidepressant medication for adult depression: a systematic review and individual participant data meta-analysis
No full text: Interpersonal psychotherapy (IPT) and antidepressant medications are both first-line interventions for adult depression, but their relative efficacy in the long term and on outcome measures other than depressive symptomatology is unknown. Individual participant data (IPD) meta-analyses can provide more precise effect estimates than conventional meta-analyses. This IPD meta-analysis compared the efficacy of IPT and antidepressants on various outcomes at post-treatment and follow-up (PROSPERO: CRD42020219891). A systematic literature search conducted May 1st, 2023 identified randomized trials comparing IPT and antidepressants in acute-phase treatment of adults with depression. Anonymized IPD were requested and analyzed using mixed-effects models. The prespecified primary outcome was post-treatment depression symptom severity. Secondary outcomes were all post-treatment and follow-up measures assessed in at least two studies. IPD were obtained from 9 of 15 studies identified (N = 1536/1948, 78.9%). No significant comparative treatment effects were found on post-treatment measures of depression (d = 0.088, p = 0.103, N = 1530) and social functioning (d = 0.026, p = 0.624, N = 1213). In smaller samples, antidepressants performed slightly better than IPT on post-treatment measures of general psychopathology (d = 0.276, p = 0.023, N = 307) and dysfunctional attitudes (d = 0.249, p = 0.029, N = 231), but not on any other secondary outcomes, nor at follow-up. This IPD meta-analysis is the first to examine the acute and longer-term efficacy of IPT v. antidepressants on a broad range of outcomes. Depression treatment trials should routinely include multiple outcome measures and follow-up assessments
On Determining Continuum Quantities of Non-Equilibrium Processes via Molecular Dynamics Simulations
No full textIn this dissertation, a high-fidelity atomistic-to-continuum link for highly non-equilibrium processes has been established by making several modifications to Hardy’s theory. Although Hardy’s thermomechanical quantities were derived analytically to conserve mass, momentum and energy, they have not been rigorously tested and validated numerically in the past.
Hence the first task was to investigate the effectiveness of ensemble averaging in removing thermal fluctuations and compare with conventional time averaging for fcc crystals simulated using both equilibrium and non-equilibrium molecular dynamics (MD) simulations, where the non-equilibrium process was introduced by a shock impact. It has been found that the ensemble averaging has better convergence than time averaging due to the statistical independence of the thermomechanical quantities computed using ensemble averaging.
The second task was to test the validity of Hardy’s theory by checking if it is able to conserve mass, momentum and energy numerically. A few highly non-equilibrium processes were simulated using MD, including Gaussian wave and shock impact propagation in 1D and 3D fcc crystals. Based on the test results, a new normalization rule has been proposed so that the computed thermomechanical quantities can conserve the fundamental properties more accurately. To a large extent, Hardy’s theory has been found to be valid regardless of the width of the localization function, the interatomic potential and crystal structure, and with and without ensemble averaging.
To further test the validity of Hardy’s theory for more complex non-equilibrium processes, where plastic deformation is accomplished through dislocation glide and slip band emission, a crack propagation problem in iron crystal with a pre-created center crack is simulated using MD. The computed Hardy’s thermomechanical quantities can generally conserve mass, momentum and energy. Exceptions have been found around the crack region, where the computed quantities cannot obey the balance of energy but still conserve mass and momentum.
The results from this dissertation will help 1) inspire confidence in employing Hardy’s theory with the proposed modifications to analyze MD simulation results, especially for non-equilibrium thermomechanical processes and 2) pave the way for concurrent atomistic/continuum coupled simulations
The use of ChatGPT for personality research: Administering questionnaires using generated personas
No full textPersonality research has traditionally relied on questionnaires, which bring with them inherent limitations, such as response style bias. With the emergence of large language models such as ChatGPT, the question arises as to what extent these models can be used in personality research. In this study, ChatGPT (GPT-4) generated 2000 text-based personas. Next, for each persona, ChatGPT completed a short form of the Big Five Inventory (BFI-10), the Brief Sensation Seeking Scale (BSSS), and a Short Dark Triad (SD3). The mean scores on the BFI-10 items were found to correlate strongly with means from previously published research, and principal component analysis revealed a clear five-component structure. Certain relationships between traits, such as a negative correlation between the age of the persona and the BSSS score, were clearly interpretable, while some other correlations diverged from the literature. An additional analysis using four new sets of 2000 personas each, including a set of ‘realistic’ personas and a set of cinematic personas, showed that the correlation matrix among personality constructs was affected by the persona set. It is concluded that evaluating questionnaires and research hypotheses prior to engaging with real individuals holds promise.Human-Robot InteractionMedical Instruments & Bio-Inspired Technolog
The set of undominated imputations and the core: an axiomatic approach
No full textThis paper provides an axiomatic framework to compare the D-core (the set of undominated
imputations) and the core of a cooperative game with transferable utility. Theorem
1 states that the D-core is the only solution satisfying projection consistency, reasonableness (from above), (*)-antimonotonicity, and modularity. Theorem 2 characterizes the core replacing (*)-antimonotonicity by antimonotonicity. Moreover, these axioms also
characterize the core on the domain of convex games, totally balanced games, balanced
games, and superadditive gamesAquest article proporciona un marc axiomàtic per a comparar el Cor de d (el joc d'imputacions indominades) i el cor d'un joc cooperatiu amb la utilitat trasferible. El teorema 1 estats que el Cor de d és l'única solució que satisfà la consistència de projecció, el raonable (des de dalt), (*)-*antimonotonicity, i la *modularitat. El teorema 2 caracteritza el substituir de cor (*)-*antimonotonicity per *antimonotonicity. A més, aquests axiomes també caracteritzen el cor sobre el domini de jocs convexs, jocs totalment equilibrats, jocs equilibrats, i jocs superadditius
Baan Hollanda Museum beschermd tegen hoogwater
No full textTijdens de overstromingen in Thailand in 2011 werd het Baan Hollanda Museum, gelegen bij een oude VOC-handelspost, getroffen. De Nederlandse ambassade vroeg de TU Delft een plan uit te werken on Baan Hollanda in de toekomst droog te houden.Hydraulic EngineeringCivil Engineering and Geoscience
Assessing driving behaviour using acceleration thresholds
No full textDifferent types of sensors that monitor the driver, the vehicle, and the surroundings are increasingly being implemented in vehicles. These developments are relevant to formal driving test organizations for the use of sensors in the assessment of driving behaviour. However, no guidelines exist about the exact use of sensor-generated data for driving assessment purposes, such as the driving exam. Relatively low-cost and easily implementable sensors such as accelerometers (g-force sensors) could be used to assess driving behaviour during the driving exam to distinguish between desired and undesired driving behaviour. Earlier studies have already investigated the use of accelerometers to distinguish between driving styles using threshold values, but do not agree on the most optimal threshold to do this. In this study, thresholds were created based on scripted driving exams driven by professional driving examiners, who portrayed driving styles commonly observed at the driving exam. These rides were driven over a period of three weeks at the Dutch driving license organisation (CBR) in Leusden, The Netherlands, where scripted exam rides are part of the training for new examiners. Using the accelerometer of an iPhone X, the accelerations generated during 21 rides were measured supported by a dashcam recording the road ahead. The experimenter drove along all rides and registered driving events, including turns, speed increases/decreases and lane changes to relate the measured accelerations to these specific events. The rides included in the dataset were divided into four different driving styles: aggressive, desired, overcautious and negligent, from which the first three were analysed due to their direct link with accelerations. The obtained acceleration data was analysed using 63 initial features which describe the amplitude of the acceleration signal through the various events, speed zones and acceleration directions.It was found that accelerations differ significantly between aggressive and desired driving styles, whilst the difference between overcautious and desired driving is less apparent. The thresholds determined in this study were able to classify the created dataset between desired and undesired driving behaviour with accuracies varying from 50% to 83% (M = 69.1, SD = 11.4). The results show that using acceleration data obtained during the driving exam can aid the examiner during the driving exam by giving insight into how well a candidate performed in terms of smooth driving through traffic. Concomitantly, a recent report from the Dutch government (Roemer, 2020) addressed that the CBR should investigate the possibilities for using sensor-collected driving data to give more insight to a driving exam candidate as to how to improve his/her driving behaviour after failing the driving exam, giving further rise to researching the use of driving data for practical use.Mechanical Engineerin
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