CROWN Project, towards a European Multifunction AESA system

The digital receiver/exciter (DREX) is a key enabling technology for next-generation affordable phased arrays. The goal is an eventual all-digital array solution employing a DREX at each array element. Wideband dual-polarized performance is highly desirable for increased radar target resolution, improved target identification, counter-counter measures, and higher data rates for communications applications. An affordable S-band radar DREX architecture is presented, consisting of a digital module, containing a low-cost field-programmable gate array (FPGA), analog-to-digital converter (ADC) and digital-to-analog converter (DAC) electronics, as well as a single-stage frequency converter employing low-cost components. Multi-channel synchronization, per-channel data storage, and back-end inphase/quadrature (I/Q) data flow and digital beamforming are discussed. Applications include radar, communications, and electronic warfare.

The demand for higher data rate and better quality of service (QoS) in wireless communications was growing fast in the past few years. Obtaining these requirements becomes challenging for wireless communication systems due to the problems of channel multi-path fading, higher power and bandwidth limitations. One of the most promising solutions to this problem is Multiple Input Multiple Output (MIMO) system. This paper proposed a combined spatial multiplexing MIMO scheme with beamforming for high data rate wireless communication. The proposed transmission scheme combines the benefits of both techniques and the system was able to transmit parallel data streams as well as providing beamforming gain. Actually, these diverse techniques, share the same requirement of multiple antenna elements, but differ in the antenna element spacing necessary for the different schemes to work. Thus, smart antenna array was proposed as a possible solution and was adopted at the both transmitter and the receiver. The hybrid technique provides higher spectral efficiency and improve better Bit error rate (BER) of the system than the conventional MIMO, spatial multiplexing and beamforming techniques under the same simulation environment.

A theoretical analysis has been made to compare the capacity performances of transmit diversity and beamforming in the downlink of direct-sequence code-division multiple-access (DS-CDMA) system. The performances of selection transmit diversity (STD), beamforming (BF), and beam selection transmit diversity (BSTD), which is a hybrid scheme of STD and BF, have been studied at system level with capacity as the performance index. Both fading and interference are jointly considered in multipath propagation environment. It was found that the comparison result strongly relates to the availability of path diversity. The system capacity is maximized by the BF in the presence of path diversity, otherwise it is the BSTD that achieves the best overall capacity performance.

The current work develops an efficient scheme to be used for the downlink of a WCDMA network, using transmitter diversity and beamforming. The performances of space-time transmit diversity (STTD) in combination with selective transmit diversity (STD), beamforming (BF) and beam selective transmit diversity (BSTD) which is a composite scheme of STD and BF, have been studied at the system level using the capacity and BER as the performances indexes. Both fading and interference are jointly considered in the multipath propagation environment. The main constraint was the implementation problem. It considers the use of an array with eight antenna elements spaced half wavelength per 120° sector to implement dynamically the several proposed techniques based on the environment. It was found that the comparison is strongly related to the availability of path diversity. The system capacity is maximized by the BF in the presence of multipath diversity and high multiple access interference. Otherwise it is the BSTD that achieves the best overall capacity performance. For higher data rates and small number of users the system that gives the best capacity performance is STTD+STD.

In this paper, we introduce an innovative system concept for synthetic aperture radar (SAR) and investigate the performance. Based on multiple-input multiple-output (MIMO) configuration, a versatile SAR operation can be feasible, for instance interferometric and full polarimetric SAR operation over a wide area simultaneously. For this purpose the space-time coding (STC) and digital beamforming (DBF) are key elements of the proposed MIMO SAR concept. A waveform diversity gain is obtained from the STC scheme, applied on transmit and DBF on receive provides array gain and improved noise performance for each multiple SAR images. In this paper, using a simple transmit diversity technique, well known as Alamouti scheme, the complete processing topology is introduced. The performance is investigated from a system point of view.

In multi-agent systems, changes in an agent's mental state often reflect changes at the social level as well. Furthermore, most work on agent languages use structural operational semantics to formalise multi-agent systems. As multi-agent systems are complex systems, it is difficult to formalise all relevant aspects of such system as a single transition system, and even transition systems for a single agent can easily become cumbersome. In this paper, we propose a particular style of semantic rules that make it visually clearer how changes at one level of a multi-agent system require simultaneous changes in other levels of the system (where each component of each level is modelled as a separate transition system).

For children with autism, the development of intentional and symbolic communication can be a challenging process and some children remain at the prelinguistic stage of communicative development for extended periods. During this time, they rely on communicative behaviours that can be difficult for others to understand and interpret. Communicative forms can be subtle and idiosyncratic and may represent more than one communicative function. This can lead to frustration for the child and the communicative partner who may struggle to understand the meaning of the child’s behaviour. Many communication breakdowns can result and with the child’s limited skills to repair these breakdowns, behaviours can escalate to problematic forms. Research has shown that children with autism have higher rates of problem behaviour which limits opportunities for engagement and learning and for participation in the community. Improving our knowledge and understanding of prelinguistic behaviours may help to reduce problem behaviours and can inform interventions to support these children to communicate their needs and wants more effectively. This chapter explores our current understanding of the prelinguistic communicative forms and functions of children with autism and identifies gaps in our knowledge base and areas in need of further research. The author draws on her work in functional communication and prelinguistic behaviours and communicative repairs.

Imaging at high temporal resolution is critical for a better understanding of transient cardiac phases with potential diagnostic value. Typically, parallel receive beam forming is used to achieve this. As an alternative, transmitting multiple lines simultaneously [i.e., multi-line transmit (MLT)] has been proposed. However, this approach has received less attention, most likely because of potential cross-talk artifacts between beams. In this study, based on different transducer configurations, the cross-talk level of different MLT systems was investigated and their point spread functions (PSFs) were compared with that of conventional beam forming (single-line transmit, SLT) by computer simulation. To reduce cross-talk artifacts, 7 different windowing functions were tested on transmit and receive: rectangular, Tukey (α = 0.5), Hann, cosine, Hamming, Gaussian (α = 0.4), and Nuttall. The simulation results showed the cross-talk varied inversely with the MLT beam opening angle and apodization could significantly reduce these artifacts at distinct opening angles, which were dependent on the transducer configuration. The optimal settings for an MLT system were highly dependent on the exact transducer configuration and must be deduced based on a given transducer. In particular, for a typical cardiac transducer configuration, a 4MLT imaging system with an opening angle of 22.73° and a Tukey (α = 0.5)-Tukey (α = 0.5) windowing scheme provided very similar image quality to SLT but with a 4 times higher frame rate. In addition, the MLT approach can be combined with (multiple) parallel receive beamforming to increase frame rate further. With these methods, a frame rate of approximately 300 Hz can be achieved to generate a 90° sector image without significant loss in image quality.

Modeling and simulation have become an important aspect of the design and development process of aircraft systems. During the design of high lift actuation systems for example, the dynamic loads in the transmission are estimated by simulation. Nevertheless huge development efforts and financial resources are still invested in physical testing. These integration and testing phases take place at a late stage in the design process. Therefore, identified malfunctions and development errors lead to undesired iterations and thus to high costs as well as to an increased development time. This issue is emphasized as system complexity is rising continuously in conjunction with an increase in the number of interconnections and functionality. Hence, early and continuous virtual testing activities on the overall system level become increasingly important. In order to establish such a process, this paper analyzes the effects of modeling depth and parameter uncertainties on the overall system behavior considering nominal operation as well as failure cases. It identifies which test cases can be performed in which development phase depending on the information required. The modeling and simulation is implemented in the multiphysics and object-oriented simulation environment Matlab/Simulink/Simscape using an example of a multifunctional high lift actuation system.

In this paper, we use eight transmitter antennas and eight receiver antennas as the circle antenna arrays. Shooting and bouncing ray/image(SBR/Image)techniques combining with antenna pattern are used to calculate the impulse response in indoor wireless environment. Beamforming techniques are employed to reduce the multi-path effect of the channel and bit error rate (BER). We adjust the excitation amplitude and feed length of each array element to synthesize the pattern of the antenna array by using the genetic algorithms (GA) and self-adaptive dynamic differential evolution (SADDE). Numerical results show that SADDE algorithm outperforms GA algorithm in terms of bit error rate performance and convergence speed.

Energy harvesting (EH), which refers to replenishing energy from the environment, is demonstrated to be a promising approach in reducing the operational expenses (OPEX) and increasing the network lifetime of emerging wireless communication technologies by eliminating the need for frequent battery replacing or recharging of wireless devices. Among various ambient energy sources, the focus of this dissertation is on wireless power transfer (WPT) considering the unique characteristic of radio frequency (RF) signals; that is, they inherently carry both information and energy. A particularly interesting scenario arises when sources support simultaneous wireless information and power transfer (SWIPT) to provide a remote, controllable, and on-demand energy source. In this context, one of the promising deployment approaches is SWIPT-enabled cognitive radio networks (CRNs), which offer significant gains in terms of spectral and energy efficiencies. One of the practical scenarios of RF-powered CRN is deploying a number of distributed cognitive sensor nodes, equipped with RF EH modules, to sense a specific area and send the sensed data to an access point while coexisting with a primary licensed network. However, exploiting the full potentials of SWIPT-enabled CRNs is subject to carefully aligning the requirements of the EH unlicensed secondary receivers (SRs) with those of the legitimate primary receivers (PRs). In light of this, the first contribution of this thesis focuses on investigating the problem of beamforming for the downlink of multi-user multiple-input single-output (MU-MISO) CRNs. With the objective of minimising the transmission power of the secondary base station (SBS), optimal and suboptimal solutions for the formulated optimisation problem are provided by jointly optimising the transmit beamforming vector at the SBS and adjusting the parameters of the energy harvesters at the SRs. It is shown that the obtained solutions are efficient in meeting the EH and quality-of-service (QoS) requirements of the SRs and the levels of interference accepted by the PRs. Apart from SWIPT-enabled CRNs, relay-assisted SWIPT networks are envisioned to be a promising framework offering extended coverage, diversity gains, and enhanced energy efficiency. In this case, the relay network itself can benefit from the relayed transmissions in terms of saving energy, and the harvested energy can be used to charge relay nodes and extend their lifetime as compensation for their role of data forwarding. Nonetheless, a concrete performance analysis on the impact of the involved system parameters such as, the energy conversion efficiency and the location of the EH relay terminal, on the trade-off between the achievable information transfer efficiency and the harvested energy level is crucial for the successful implementation of SWIPT in this context. This inspired the research work in the next two contributions with the main focus on developing novel comprehensive analytical frameworks for the investigation and evaluation of SWIPT relaying systems. Specifically, the second contribution is dedicated to examining the application of noncoherent modulation, which is recognised as an energy efficient modulation scheme for SWIPT, due to its ability to eliminate the need of instantaneous channel state information (CSI) estimation/tracking. Through adopting a moments-based approach, novel expressions are derived for the outage probability, achievable throughput, and average symbol error rate (ASER) of dual-hop SWIPT relaying systems. Furthermore, new asymptotic analytical results are derived for the high SNR regime and are then utilised to analytically quantify the achievable diversity order. The proposed mathematical tools are demonstrated to be an accurate and efficient means by which one can conduct a thorough analysis on the system performance without the burden of Monte Carlo simulations. Finally, the third contribution focuses on SWIPT relaying systems operating in the presence of impulsive non-Gaussian noise, which is typical in several practical scenarios. Several studies show sufficient evidences that impulse man-made noise is encountered in various metropolitan, indoor, and underwater wireless applications. Examples of these sources include automotive ignition, electronic devices, household appliances, medical equipment, and industrial equipment. To characterise the behavior of the system performance under this type of noise, an efficient analytical framework is developed where novel closed-form xpressions for the pairwise error probability (PEP) are derived for two relaying schemes, namely, blind relaying and CSI-assisted relaying, employed under two assumptions imposed on the deployed EH process; namely, instantaneous EH (IEH) and average EH (AEH). Apart from being accurate, the derived expressions are shown to be efficient in quantifying the diversity order of the system and providing a comprehensive study on the impact of the severity of impulsive noise on the behavior of the system.

Software architecture is receiving increasingly attention as a critical design level for software systems. However the current practice of architectural description is largely informal and ad hoc, with the consequence that architectural documents serve as a poor communication mechanism, are difficult to analyze, and may have very little relationship to the implemented system. In an attempt to address these problems several researchers have experimented with formalisms for architectural specification and modelling. One such formalism is the WRIGHT specification language. In this paper, we show how WRIGHT can be used to provide insight into an architectural design by modelling a prototype implementation of part of the AEGIS Weapons System (AWS).

The article focuses on the aggravation of the problem of legal education of adolescents and in particular of pupils with learning disabilities and describes the ways to solve it. The reasons for deviant behavior of pupils, the typology of deviation from the norm are revealed, and the principles of individualization, flexibility and variability, which are the basis for developing an individual program of actions for the upbringing and re-education of adolescents, are described. The topics of educational hours and round tables to promote the protection of children's rights and the Universal Declaration of Human Rights are proposed. In this regard, the new functions of the tutor in working with pupils of deviant behavior are justified, and specific recommendations for organizing tutors based on the principle of individualization of legal education are highlighted. The author emphasizes the priority of interpersonal communication between the tutor and teenagers with learning disabilities. The article accentuates the formative function of communication; it describes the function of the pupil status confirmation and the function of interpersonal communication, which helps to bring out the potential of positive feelings and emotions. The research emphasizes the importance for the tutor to learn about the living conditions of the pupils with learning disabilities, their relationships with parents, surrounding, with other teenagers after classes. It is underlined that the tutor must consider the typology of these teenagers’ psychic, which will allow the tutor to develop a further program of actions. The author offers the typology by V.M. Soroka – Rosinsky and his scientific and pedagogical approaches to educating children with different types of deviant behavior.  

Progressive trends in ultra-broadband active electronically scanned array (AESA) antennas for multifunctional RF sensor systems are discussed with their inherent system aspects to cope with. New scalable and modular AESA concepts to reduce size, weight, power and costs (SWAP-C), as well as the prospects of digital frontends with their technological challenges and operational benefits are presented. Furthermore special topics of state of the art AESA component technologies such as GaN-SiGe transmit-receive module (TRM) designs, novel developing trends from multi-chip to two-chip TRMs, as well as surface mounted device (SMD) capable system on chip (SoC) monolithic microwave integrated circuits (MMICs) and digital SoC are addressed.

Due to the current challenging environment in Oil and Gas industry, cost effective hydrocarbon recovery from Subsea Wells is mandating innovative methods in equipment design construction and qualification. Different types of intervention systems are required based on the issue being addressed, the intervention technique being used, depth of water, geographical locations, vessel types and pressure/temperature conditions. The industry is increasingly utilizing well access solutions such as Open water riser system and Light Well Intervention System not only for equipment installation, but also to improve efficiency of operations, to facilitate life-of-field hydrocarbon production enhancement and restorative intervention techniques. Suppliers and Operators of subsea intervention system need to rise to the challenge of meeting increasingly stringent industry standards and customer requirements. This necessitates but is not limited to the importance of utilizing effective seal design, robust barrier design, advanced materials and safety rated control systems with rigorous design and qualification test validation. The more demanding requirements of the move to deeper and deeper water and higher pressures and temperatures have led to enormous challenges both at the component and system level. This is driving the incorporation of the latest technology on both metallic and non-metallic seals for high temperature application. This is particularly relevant in valve qualification for field producing hydrocarbons with high levels of sand. Size and weight reduction design strategies for equipment destined to be used in deep water allows for effective selection of existing rigs and vessels of opportunity. Advanced design validation including 3D printing of components has resulted in more accurate and predictable results for Component interactions, Strength Integrity and Fatigue Capacity. Thermal analysis used for prediction has allowed for prevention of hydrate formation which has proved essential to validation of the intervention system performance. To qualify subsea components in deep water, technology enhancements, the latest manufacturing techniques and supply chain approaches, welding techniques etc. are critical to success. Deepwater System challenges include communicating and controlling the well and Xmas tree remotely through an Installation and Workover Control System. This can be resolved with design of optimized safety-rated electro-hydraulic system along with a robust sensor system which provides a safe and reliable method for hydrocarbon containment during critical well intervention operations. This paper will depict some of the latest design techniques required to deliver advanced equipment to the Intervention market. The areas addressed will be: Identification of the technology challenges, providing right solution, usage of design tools for equipment design advancement and managing risk.