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Massive multiple-input multiple-out (MIMO) technology and mm wave are important technologies in 5G/6G to enhance the spectrum efficiency and system capacity. However, it has a lot of challenges in mm wave range, such as high hardware cost and power consumption in such systems. Hybrid beamforming is an interesting solution with less number of RF transvers than antennas. In this paper, we will prese
Software engineers handle a lot of information intheir daily work. We explore how software engineers interact withinformation management systems/tools, and to what extent thesesystems expose users to increased cognitive load. We reviewed theliterature of cognitive aspects, relevant for software engineering,and performed an exploratory case study on how software engi-neers perceive information syst
A resonant characteristic mode (CM) is useful for antenna design if it is properly excited and well matched to the source. In this paper, we consider the feed design for the excitation of the fundamental CM of a rectangular chassis. The tradeoff between the required number of capacitive coupling elements (CCE) and matching elements used for achieving a given antenna bandwidth is studied. The resul
Copy-paste-modify is a form of software reuse in which developers explicitly duplicate source code. This duplicated source code, amounting to a code clone, is adapted for a new purpose. Copy-paste-modify is popular among software developers, however, empirical evidence shows that it complicates software maintenance and increases the frequency of bugs. To allow developers to use copy-paste-modify w
This paper presents a robust timing synchronization method for full duplex orthogonal frequency division multiplexing (OFDM) systems based on Long Term Evolution (LTE). The proposed method contains two essential steps: 1) time alignment between the desired signal and self-interference 2) normalized synchronization peak (NSP) index switching. The time alignment is to make the difference in arrival
Controlled experiments on software variants enable e-commerce companies to increase sales by providing user-adapted functionality. Our goal is to understand how the context of experimentation influences tool support. We performed a case study at Apptus that develops algorithms for e-commerce. We investigated how the case company uses experiments through five semi-structured interviews. We identifi
The online-coupled 3-D chemistry transport model COSMO-MUSCAT was enhanced by a detailed description of aqueous phase chemical processes. The aqueous phase chemistry is represented by the detailed chemical mechanism CAPRAM 3.0i reduced (C3.0RED). In addition, the deposition schemes were improved in order to account for the deposition of matter incorporated in cloud droplets of ground layer clouds
Reliance on data for software systems engineering is increasing, e.g., to train machine learning applications. We foresee increasing costs for data collection and maintenance, leading to the risk of development budgets eaten up by commodity features, thus leaving little resources for differentiation and innovation. We therefore propose Open Collaborative Data (OCD) - a concept analogous to Open So
Background: In software engineering, industry-academia is a symbiotic relationship. Researchers need to be aware of the industry to produce relevant research, while practitioners are educated in academia and could take advantage of empirical research. The SERP taxonomy architecture is designed to support communication between practitioners and researchers in software engineering. Objective: The pu
Running regression tests for Modelica models usually takes a long time. This paper presents a safe regression test selection technique for Modelica based on static analysis. The technique tracks dependencies between classes to compute which tests that need to be run given a change. The dependency rules have been verified using mutation testing. The technique has been evaluated on the Modelica Stan
Just like current software systems, models are characterised by increasing complexity and rate of change. Yet, these models only become useful if they can be continuously evaluated and validated. To achieve sufficiently low response times for large models, incremental analysis is required. Reference Attribute Grammars (RAGs) offer mechanisms to perform an incremental analysis efficiently using dyn
Massive multiple-input multiple-output (MIMO) is one of the key candidates for the upcoming 5G wireless generation. It offers a multitude of advantages over traditional techniques, such as reduced latency, reduced interference among user equipments (UEs) and increased spectrum and energy efficiencies. However, to verify the theoretically promised gains in real-life, prototype systems are inevitabl
For a firm in an open source software (OSS) ecosystem, the requirements engineering (RE) process is rather multifaceted. Apart from its typical RE process, there is a competing process, external to the firm and inherent to the firm’s ecosystem. When trying to impose an agenda in competition with other firms, and aiming to align internal product planning with the ecosystem’s RE process, firms need
Context: In the Requirements Engineering (RE) process of an Open Source Software (OSS) community, an involved firm is a stakeholder among many. Conflicting agendas may create miss-alignment with the firm's internal requirements strategy. In communities with meritocratic governance or with aspects thereof, a firm has the opportunity to affect the RE process in line with their own agenda by gaining
In this paper we present fully decentralized methods for calculating an approximate zero- forzing (ZF) equalizer in a large intelligent surface (LIS). A LIS is intended for wireless communication and facilitates unprecedented MU- MIMO performance, far superior to that of Massive MIMO. Antenna modules in the grid connect to their neighbors to exchange messages of information needed for interference
This paper presents the architecture and the corresponding simulation results for a very low power half-rate extended Hamming (8,4) decoder implemented in analog integrated circuitry. TI’s 65nm low power CMOS design library was used to simulate the complete decoder including an input interface, an analog decoding core and an output interface. The simulated bit error rate (BER) performance of the d
Internet-of-things (IoT) systems consist of spatially distributed devices with services. Compared to desktop applications, IoT systems are always running and need to deal with unresponsive devices and weak connectivity. In this thesis, we examine the following question: How can we simplify the development of IoT systems? We begin to answer this question by proposing a domain-specific language (DSL
