Evaluating the Quality of Experience Performance Metric for UAV-Based Networks

In this work, we consider a UAV-assisted cell in a single user scenario. We consider the Quality of Experience (QoE) performance metric calculating it as a function of the packet loss ratio. In order to acquire this metric, a radio-channel emulation system was developed and tested under different conditions. The system consists of two independent blocks, separately emulating connections between the User Equipment (UE) and unmanned aerial vehicle (UAV) and between the UAV and Base station (BS). In order to estimate scenario usage constraints, an analytical model was developed. The results show that, in the described scenario, cell coverage can be enhanced with minimal impact on QoE.

ROBUST MULTI-OBJECTIVE OPTIMIZATION IN PRODUCT DEVELOPMENT WITH RESPECT TO USER-SCENARIO AND MANUFACTURING UNCERTAINTIES

In product development, user-scenarios are a way of tailoring requirements to defined customer groups. Furthermore, a product design often involves multiple conflicting objectives that are analyzed within an iterative process. The models typically used for the analysis often do not accurately reflect the real-world representation. This can be alleviated by finding robust product designs. While usually uncertainties due to manufacturing tolerances are investigated, we additionally consider uncertainties in the user-scenario. Therefore, we present a robustness evaluation in a multi-objective numerical optimization in product development. For this, we consider manufacturing tolerances using an adjusted Latin Hypercube Sampling as well as deviations in the user-scenario by means of a Gaussian distribution. In the case study, we present the robust development of a customer specific coffee machine, where we show the robustness evaluation and the impact of the proposed adjustments. The advantage of the presented process is a product design tailored to the customer's requirements under specified uncertainties. In addition, this enables a time benefit in the product development due to the automated analysis used in the optimization.

What citizens experience and how omni-channel could help–insights from a building permit case

PurposeBy increasing the digitalization of commercial services citizens' expect more from public services. First of all, this study will strive to identify which problems citizens encounter when they use a complex public service: preparation of an application for a building permit. In the light of the popularity of omnichannel approaches, the study then explores how omni-channel could help to address the problems which have been identified.Design/methodology/approachWe implement the first phases of an action design science research project. We collect data both from citizens and public agencies and frame them as transparency problems. These abstract problems are then addressed by an omnichannel service provision as an abstract solution. The abstract solution is then instantiated in a design in the form of a user scenario developed in collaboration with current and future public officials.FindingsThe analysis uncovers multiple transparency issues: it distinguishes between process, case, language, cross-channel and cost transparency. One root cause of the transparency issues observed is the lack of service transparency which defines the purpose and scope of a ser-vice. We therefore recommend defining a service-strategy before informational and technical aspects of an omnichannel approach can be implemented. Following this strategy, omnichannel offers public administrations unique opportunities to excel in citizens' service provision.Originality/valueThe study provides insights into how citizens view complex public services. For researchers, this study offers the conceptualization as transparency issues. Practitioners from the public administrations can also benefit from the concept and vision of omnichannel public services.

Integrated User-Oriented Service for 3D Printing Environments with Recycled Material from Maritime Plastic Waste

Plastic waste is a major concern for marine environment care, and many researchers and projects face the problem from different points of view. The European CircularSeas project aims to encourage the development of greener maritime industries through the combination of principles of Circular Economy, plastic recycling and 3D printing. However, while 3D printing has shown its benefits for conventional industry environments, the first issue discussed in this paper is whether 3D printing technology can also bring benefits to the maritime-port sector, where parts manufacturing, new prototyping trends and even product customization have not traditionally been major business issues. A secondary issue is how 3D printing and this specific user scenario could accommodate recycled plastic in a Circular Economy strategy in a feasible way. In an attempt to address both of these issues, the paper reviews some particularities of 3D printing open technologies and proposes a new integrated and user-oriented 3D printing framework, independent of hardware and adaptable to non-standard recycled plastic raw material from marine waste.

Efficient Bit Loading Algorithm for OFDM-NOMA Systems with BER Constraints

This paper considers applying bit loading to multicarrier non-othogonal multiple access (NOMA) systems. The objective is to maximize the system total throughput while satisfying the users' individual quality of service (QoS) constraints. Although bit loading is generally an NP-hard problem, even for orthogonal multiple access (OMA), the mutual interference between the users and the dependence of power coefficients and modulation orders are additional challenges that add substantial complexity to the optimization problem. Therefore, we propose in this paper an efficient bit loading algorithm for multicarrier NOMA systems and compares the complexity and throughput with OMA. The obtained results show that NOMA has virtual cognition and hybrid modes of operation, NOMA/OMA, that enables NOMA to outperform OMA by 100% for the two-user scenario. The complexity of the loading process for NOMA is noticeably higher than OMA, which is due to the high computational complexity of bit error rate (BER) computation for NOMA. The obtained results show that the NOMA throughput depends on which user is loaded first, and on the initially loaded bits.

Efficient Bit Loading Algorithm for OFDM-NOMA Systems with BER Constraints

This paper considers applying bit loading to multicarrier non-othogonal multiple access (NOMA) systems. The objective is to maximize the system total throughput while satisfying the users' individual quality of service (QoS) constraints. Although bit loading is generally an NP-hard problem, even for orthogonal multiple access (OMA), the mutual interference between the users and the dependence of power coefficients and modulation orders are additional challenges that add substantial complexity to the optimization problem. Therefore, we propose in this paper an efficient bit loading algorithm for multicarrier NOMA systems and compares the complexity and throughput with OMA. The obtained results show that NOMA has virtual cognition and hybrid modes of operation, NOMA/OMA, that enables NOMA to outperform OMA by 100% for the two-user scenario. The complexity of the loading process for NOMA is noticeably higher than OMA, which is due to the high computational complexity of bit error rate (BER) computation for NOMA. The obtained results show that the NOMA throughput depends on which user is loaded first, and on the initially loaded bits.

Communications using Sparse Signals

Inspired by compressive sensing principles, we propose novel error control coding techniques for communication systems. The information bits are encoded in the support and the non-zero entries of a sparse signal. By selecting a dictionary matrix with suitable dimensions, the codeword for transmission is obtained by multiplying the dictionary matrix with the sparse signal. Specifically, the codewords are obtained from the sparse linear combinations of the columns of the dictionary matrix. At the decoder, we employ variations of greedy sparse signal recovery algorithms. Using Gold code sequences and mutually unbiased bases from quantum information theory as dictionary matrices, we study the block error rate (BLER) performance of the proposed scheme in the AWGN channel. Our results show that the proposed scheme has a comparable and competitive performance with respect to the several widely used linear codes, for very small to moderate block lengths. In addition, our coding scheme extends straightforwardly to multi-user scenarios such as multiple access channel, broadcast channel, and interference channel. In these multi-user channels, if the users are grouped such that they have similar channel gains and noise levels, the overall BLER performance of our proposed scheme will coincide with an equivalent single-user scenario.

Communications using Sparse Signals

Inspired by compressive sensing principles, we propose novel error control coding techniques for communication systems. The information bits are encoded in the support and the non-zero entries of a sparse signal. By selecting a dictionary matrix with suitable dimensions, the codeword for transmission is obtained by multiplying the dictionary matrix with the sparse signal. Specifically, the codewords are obtained from the sparse linear combinations of the columns of the dictionary matrix. At the decoder, we employ variations of greedy sparse signal recovery algorithms. Using Gold code sequences and mutually unbiased bases from quantum information theory as dictionary matrices, we study the block error rate (BLER) performance of the proposed scheme in the AWGN channel. Our results show that the proposed scheme has a comparable and competitive performance with respect to the several widely used linear codes, for very small to moderate block lengths. In addition, our coding scheme extends straightforwardly to multi-user scenarios such as multiple access channel, broadcast channel, and interference channel. In these multi-user channels, if the users are grouped such that they have similar channel gains and noise levels, the overall BLER performance of our proposed scheme will coincide with an equivalent single-user scenario.