Testing the dimensionality of the quality management construct

© 2014 Taylor & Francis. Numerous empirical studies have conceptualised quality management (QM) as either a multidimensional or unidimensional construct. While few prior studies tested some aspects of the assumed dimensional structure of the construct, no study has been found to have tested the construct's dimensionality using alternative factor analysis models. To gain a better insight into dimensional properties of the QM construct, this paper tests its dimensionality using three confirmatory factor analysis models (oblique factor model, higher-order factor model, and one-factor model) on a subset of data collected in a larger study that investigated the effects of QM on competitive advantage using a sample of 288 hotel managers in Egypt. The results of the three tests indicate that the QM construct is multidimensional. While this study contributes to advancing the QM theory and practice, further studies are needed to investigate the dimensional properties of the construct in greater depth. The results of this study may therefore stimulate research in this area and encourage the much needed debate on the dimensionality of the QM construct

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Downlink and Uplink Decoupling: a Disruptive Architectural Design for 5G Networks

Cell association in cellular networks has traditionally been based on the downlink received signal power only, despite the fact that up and downlink transmission powers and interference levels differed significantly. This approach was adequate in homogeneous networks with macro base stations all having similar transmission power levels. However, with the growth of heterogeneous networks where there is a big disparity in the transmit power of the different base station types, this approach is highly inefficient. In this paper, we study the notion of Downlink and Uplink Decoupling (DUDe) where the downlink cell association is based on the downlink received power while the uplink is based on the pathloss. We present the motivation and assess the gains of this 5G design approach with simulations that are based on Vodafone's LTE field trial network in a dense urban area, employing a high resolution ray-tracing pathloss prediction and realistic traffic maps based on live network measurements.Comment: 6 pages, 7 figures, conference paper, submitted to IEEE GLOBECOM 201

Interference-Aware Decoupled Cell Association in Device-to-Device based 5G Networks

Cell association in cellular networks is an important aspect that impacts network capacity and eventually quality of experience. The scope of this work is to investigate the different and generalized cell association (CAS) strategies for Device-to-Device (D2D) communications in a cellular network infrastructure. To realize this, we optimize D2D-based cell association by using the notion of uplink and downlink decoupling that was proven to offer significant performance gains. We propose an integer linear programming (ILP) optimization framework to achieve efficient D2D cell association that minimizes the interference caused by D2D devices onto cellular communications in the uplink as well as improve the D2D resource utilization efficiency. Simulation results based on Vodafone's LTE field trial network in a dense urban scenario highlight the performance gains and render this proposal a candidate design approach for future 5G networks.Comment: 5 pages, 5 figures. Accepted in IEEE VTC spring 201

Bio-Inspired Resource Allocation for Relay-Aided Device-to-Device Communications

The Device-to-Device (D2D) communication principle is a key enabler of direct localized communication between mobile nodes and is expected to propel a plethora of novel multimedia services. However, even though it offers a wide set of capabilities mainly due to the proximity and resource reuse gains, interference must be carefully controlled to maximize the achievable rate for coexisting cellular and D2D users. The scope of this work is to provide an interference-aware real-time resource allocation (RA) framework for relay-aided D2D communications that underlay cellular networks. The main objective is to maximize the overall network throughput by guaranteeing a minimum rate threshold for cellular and D2D links. To this direction, genetic algorithms (GAs) are proven to be powerful and versatile methodologies that account for not only enhanced performance but also reduced computational complexity in emerging wireless networks. Numerical investigations highlight the performance gains compared to baseline RA methods and especially in highly dense scenarios which will be the case in future 5G networks.Comment: 6 pages, 6 figure

Aerodynamic Optimization and Wind Load Evaluation Framework for Tall Buildings

Wind is the governing load case for majority of tall buildings, thus requiring a wind responsive design approach to control and assess wind-induced loads and responses. The building shape is one of the main parameters that affects the aerodynamics that creates a unique opportunity to control the wind load and consequently building cost without affecting the structural elements. Therefore, aerodynamic mitigation has triggered many researchers to investigate various building shapes that can be categorized into local (e.g. corners) and global mitigations (e.g. twisting). Majority of the previous studies compare different types of mitigations based on a single set of dimensions for each mitigation types. However, each mitigation can produce a wide range of aerodynamic performances by changing the dimensions. Thus, the first millstone of this thesis is developing an aerodynamic optimization procedure (AOP) to reduce the wind load by coupling Genetic Algorithm, Computational Fluid Dynamics (CFD) and an Artificial Neural Network surrogate model. The proposed procedure is adopted to optimize building corners (i.e. local) using three-dimensional CFD simulations of a two-dimensional turbulent flow. The AOP is then extended to examine global mitigations (i.e. twisting and opening) by conducting CFD simulations of three dimensional turbulent wind flow. The procedure is examined in single- and multi-objective optimization problems by comparing the aerodynamic performance of optimal shapes to less optimal ones. The second milestone is to develop accurate numerical wind load evaluation model to validate the performance of the optimized shapes. This is primary achieved through the development of a robust inflow generation technique, called the Consistent Discrete Random Flow Generation (CDRFG). The technique is capable of generating a flow field that matches the target velocity and turbulence profiles in addition to, maintaining the coherency and the continuity of the flow. The technique is validated for a standalone building and for a building located at a city center by comparing the wind pressure distributions and building responses with experimental results (wind tunnel tests). In general, the research accomplished in this thesis provides an advancement in numerical climate responsive design techniques, which enhances the resiliency and sustainability of the urban built environment

The relationship between quality management and competitive advantage : an empirical study of the Egyptian hotel industry

According to the resource based view (RBV) of the firm, quality management (QM) is one of the sources the firm can use to generate competitive advantage (CA). Although QM and CA have widely attracted the attention of both academics and practitioners, the link between these two concepts has rarely been examined in the literature, especially in service industry. Additionally, among those few studies that investigated the relationship between QM and CA, there is contradictory evidence on which QM practices generate CA. Thus, this study examines the impact of QM on CA in the hotels industry, in order to identify which QM practices generate CA. Based on an extensive review of the literature on QM and CA, valid and reliable definitions were formulated for both concepts, and then a conceptual framework was developed to illustrate the relationships between the research variables. Data obtained from a survey of 384 four and five star hotels in Egypt is used to test the impact of QM on CA. A total of 300 responses were obtained. Twelve uncompleted questionnaires were removed, leaving 288 usable questionnaires and yielding a response rate of 75 %. All questionnaires were completed by the hotel general managers. Three main data analysis techniques were employed: exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and structural equation modelling (SEM). Three models are employed in CFA to test the dimensional structure of QM. These models include a model that allows all factors to be freely correlated (oblique factor model), a model where all factors are correlated because they all measure one higher order factor (higher order factor model), and a model where all indicators are employed to test if they measure only one construct. The results of CFA provide solid statistical evidence that affirm the multidimensionality of the QM construct and contradict other studies that employed QM as a unidimensional construct. These results assist in resolving the problems that might arise from the lack of clarity in the literature concerning the dimensional structure of QM. The SEM results affirm that the soft QM practices such as top management leadership (TML), employee management (EM), customer focus (CF), and supplier management (SM) directly improve the hotel financial performance but the hard QM practices such as process management (PM) and quality data and reporting (QD&R) do not. However, two quality management practices, TML and SM, are found to distinguish those hotels that have CA from those hotels that have not. Therefore, these results can help hotel managers to reallocate the hotel resources to implement those QM practices that can improve the hotel financial performance and generate CA. Finally, this study would benefit if these models are tested with an alternative data set. This study also suffered from a limitation common to survey research and SEM. The current study survey, due to time and money constraints, is a cross sectional sample at one specific point in time. As a result, while causal relationships can be inferred, they cannot be strictly proven. Causal inferences are stronger with longitudinal studies

Assessing the Mechanical Response of Pavements During and After Flooding

Flooding is recognized as a catastrophic event and a threat to the load carrying capacity of pavements around the world. In the aftermath of flooding, the pavement structure could be inundated and fully saturated. The significant increase of water within pavement layers may cause weakness and induce damage with traffic loading, subsequently increasing maintenance costs and shortening pavement service life. The assessment of the structural performance and capacity of flooded pavements remains complicated due to lack of structural data immediately following flooding, and information about the pavement structure and materials is not always readily available. Currently, the decision to open roads for traffic is based on the assessment of the pavements, which relies on visual inspection and experience. An incorrect assessment of the flooded pavement structural capacity due to unforeseen conditions may lead to unexpected outcomes or failure. The objective of this dissertation is to advance the current knowledge of the behavior of flooded pavements, based on their performance properties and structural capacities. Several methodologies have been developed and examined for a set of pavement structures with different material types using layered elastic analysis to (1) investigate the pavement response to traffic loads under different moisture conditions, (2) identify the important parameters that affect the performance of inundated pavements, (3) investigate the influence depth of the subsurface water level at which the road can withstand traffic with zero to minimum deterioration, (4) estimate the in-situ pavement surface deflection, and (5) identify the catastrophic failure of pavements in post-flood events. The findings showed a significant reduction in structural capacity when the pavement structure was in the fully saturated condition, but the road could regain its capacity after desaturation and recession of water level. The influence depth for the subsurface water level was found to be dependent on pavement structure and material type. The most accurate method to estimate the in-situ measured deflection is to divide the soil layer into several layers in the layered elastic analysis. Accurate layer thicknesses, traffic type, and interlayer bond condition are the important factors for evaluating changes in expected horizontal strain at the bottom of asphalt layer, used for predicting fatigue cracking pavement performance. The type of base and subgrade materials are the most important factors for evaluating the changes in expected vertical strain at the top of subgrade layer, used to predict pavement rutting performance. This dissertation provides information to agencies that will enhance their understanding of the performance and structural capacity of pavements in post-flood events

Porphyrin Cross-Linkers for Generating Soluble Molecularly Imprinted Polymers from Polyethyleneimine

Molecular recognition is vital to many biochemical processes and is at the heart of promising bio-medically related technologies. Molecular imprinting has a long-standing history as a successful method for mimicking the molecular recognition phenomena exhibited by nature, whereby artificial receptors are prepared for a given target molecule based on synthetic polymers. The molecularly imprinted polymer (MIP) contains a three dimensional network with a memorized cavity specific to the shape and functionality of the templated target molecule. The utility of traditional MIPs has been limited due to an inherent lack of solubility. We have worked toward developing a system that allows for the preparation of soluble MIPs targeting quadruplex DNA, specifically the human telomeric repeat (TTAGGG)4. To do so we have synthesized a series of meso-substituted, water soluble, tetracationic pyridinium porphyrins which we have successfully coupled to polyethyleneimine (PEI), forming a condensation polyamide. We have demonstrated that one of these porphyrins can be used as an efficient polymer cross-linker, which provides a unique quadruplex DNA binding site in the polymer network. Unfortunately, the high cationic charge density found on PEI has been found to elicit potential dilemmas in the utility of this method. Attempts have been made to reduce this charge by increasing the cross-linking agent and partially acetylating the PEI. While the network structure of this soluble cross-linked polymer still requires optimization, it has shown promise and demonstrates the opportunities for new soluble molecularly imprinted polymer designs that include quadruplex binding sites

Capteur d’hydrogène mos et méthode d’intégration à une technologie de transistor FDSOI

Abstract: hydrogen can be used as an energy carrier (storage) by the renewable energy industry as well as the automotive industry (fuel cell). Other industries already use hydrogen such, food processing and petroleum refineries. Hydrogen is odorless, transparent, and has a lower explosive limit of 4 %. Reliable, fast sensor are essential tools for a hydrogen safe environment. The work of this thesis provides a semiconductor-based hydrogen sensing solution. A MOS capacitor using a CMOS compatible novel Pt/Ti/ALD-Al2O3/p-Si stack. The Pt/Ti/Al2O3 sensing interface materials thicknesses are 100/5/38 nm respectively. The device can detect very low concentrations < 20 ppm. Furthermore, for a concentration of 500 ppm the response time is 56 s. the impact of testing conditions such temperature, and total gas flow have been studied. Results show that at 60℃ the device does not respond to hydrogen. And at 80℃ or higher the sensing response time is significantly reduced with increasing temperature. Furthermore, the total gas flow has an impact on the device response time and shows that a portion of the time response delay can be attributed to the chamber’s volume. Moreover, a heterogeneous integration method has been designed and presented. The latter represents a great tool for a flexible prototyping of sensors using FDSOI transistor technology. The integration has been simulated and results show promising results. The capacitive coupling feature in the FDSOI between the front and back gate is used to amplify the potential variation at the front gate. For instance, a 0.3 V hydrogen induced dipole potential can be amplified by a factor of 14 x.Le travail de cette thèse comprend la conception et la fabrication d’une technologie de capteur d’hydrogène basée sur une structure MOS. La structure est composée d’un empilement de Pt/Ti/Al2O3/p-Si. Les épaisseurs des matériaux utilisés pour la fabrication sont 100/5/38 nm (Pt/Ti/Al2O3) sur un substrat de silicium. Le capteur est capable de détecter de très faibles concentrations < 20 ppm. De plus, pour une concentration de 500 ppm, le temps de réponse est 56 s. L’impact de plusieurs conditions de test, comprenant la température et le débit total dans la chambre a été évalué. Les résultats montrent qu’à 60℃ le dispositive n’est pas capable de détecter la présence d’hydrogène. Cependant, à partir d’une température de 80℃, la réponse est très importante et le temps diminue pour encore des températures plus élevées. Le débit total dans la chambre a aussi démontré un impact sur le temps de réponse du capteur. Ce qui est aussi relié au volume de la chambre. Une intégration hétérogène ensuite a été conçue et présentée. Cette dernière est un outil flexible pour le prototypage avec des technologies de transistor FDSOI. L’intégration des deux dispositifs a été effectuée et montre de résultats prometteurs. Le couplage capacitif entre la grille avant et la grille arrière du transistor FDSOI permet d’amplifier le signal du capteur. Par exemple, une variation de potentiel de 0.3 V peut être amplifier par un facteur de 14 x, donc 4.19 V