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The nine papers in this special section focus on new developments in agile software and reports on applications for its use. A key aspect for the extensive use of agile software is that it supports developers with coping with the growing uncertainty and turbulence in technological and market environments. Feedback and change are at the core of Agile for a dynamic, evolving, and organic, rather than static, predefined, and mechanistic development process advocated by waterfall management. To create timely, high-quality, cost-efficient, and innovative solutions, Agile developers organized in small, colocated, autonomous teams, build and test software in rapid iterative cycles, actively involving users to gather feedback, updating the project scope, and plan "on-the-fly," using face-to-face communication as opposed to documentation. These papers contribute to the state-of-the-art of agile research by offering a rich, up-todate account of the dynamics occurring when expanding Agile into "not-just-software" contexts of the key challenges and perils related to the scaling and of the possible solutions to them. [ABSTRACT FROM AUTHOR]

As software products increasingly become part of larger ecosystems, research and development (R&D) units of software producers organize themselves around projects to become more responsive to the environment. Organizations participating in software ecosystems must continuously adapt and adjust their software development and maintenance processes to drive both medium-term and long-term innovation. Agile methods and practices are widely adopted to guide the collaboration within and between project teams in software development. Moreover, when successfully attained, agility can drive innovation by enabling software development organizations to cope with technological changes and exploit emerging opportunities in software ecosystems. In this article, we focus on how organizations attain agility in the maintenance and development of software products. To answer this question, we conduct a longitudinal case study of Agile Scrum implementation in the R&D unit of a major supplier of telecommunication equipment. We investigate the emerging tensions and highlight practices used to balance these tensions in the Agile Scrum implementation. We identify four capabilities and ten practices that support effective collaboration and coordination in the development and maintenance of software products. The study offers practical guidance for R&D managers to attain agility in software ecosystems. [ABSTRACT FROM AUTHOR]

In order to increase the ability to build complex, software-intensive systems, as well as to decrease time-to-market for new functionality, automotive companies aim to scale agile methods beyond individual teams. This is challenging, given the specifics of automotive systems that are often safety-critical and consist of software, hardware, and mechanical components. In this article, we investigate the concrete reasons for scaling agility beyond teams, the strategies that support such scaling, and the foreseeable implications that such a drastic organizational change will entail. The investigation is based on a qualitative case study, with data from 20 semistructured interviews with managers and technical experts at two automotive companies. At the core of our findings are observations about establishing an agile vehicle-level feedback loop beyond individual teams. First, we find that automotive original equipment manufacturers aim to decrease the lead time of development. Second, we also identify seven strategies that aim to enable scaled-agile beyond teams. Finally, we extract six foreseeable implications and side effects of scaling agile beyond teams in automotive. By charting the landscape of expected benefits, strategies, and implications of scaling agile beyond teams in automotive, we enable further research and process improvements. [ABSTRACT FROM AUTHOR]

Dealing with an uncertain and dynamic environment when facing multiple and fast-paced challenges forces professionals to adopt agile practices in different environments, resulting in the use of hybrid project management models. However, identifying the right practice to adopt can be challenging, given the variety of project types and environmental factors. In this article, a recommendation method that would allow for the identification of patterns of project management practices for different environments—using an agility indicator—is proposed. The proposed method is tested with a dataset of 856 projects. A cluster analysis is applied to divide the projects into three groups according to environmental characteristics, called scenarios: waterfall, agile, and hybrid. Then, we apply the association rule technique for each group separately, identifying specific patterns of practice for each group. Through a comparative analysis, we verify the consistency between the recommendations of the proposed method for each scenario and the literature on project management. The results indicate the feasibility of the proposed method, thus opening up new research opportunities for hybrid models that can be customized for different projects. This article can help project management professionals apply the agile method beyond its use in software development and improve the process of combining project management practices. We also suggest directions for new research to advance the knowledge of useful decision support tools for hybrid model customization. [ABSTRACT FROM AUTHOR]

The cultural component of the project team is recognized as one of the most critical factors in the implementation of agile project management (APM), especially in nonsoftware industries, where the diffusion of APM still involves several challenges. Particularly, the successful implementation of scrum—the most diffused APM methodology—seems related to the project teams’ subculture, which may differ from the overall organizational culture of the company. This article contributes to the APM literature in nonsoftware contexts by studying the cultural values that develop inside agile teams and the scrum principles and practices that are particularly relevant for fostering these values. Using interview data collected from seven manufacturing and service organizations, we use the competing value framework as the theoretical model to understand the cultural profiles of their organizations, how they deploy into the project teams’ subculture, and what, if any, connections exist with the adoption of scrum principles and practices. We find that clan and market values are the dominant subcultures in agile teams. These cultural values are fostered at a strategic level by a subset of scrum values (i.e., courage, openness, and respect) and pillars (i.e., transparency and adaptation). At an operational level, retrospective meetings and the definition of particular artifacts also contribute to develop these dominant cultural values. [ABSTRACT FROM AUTHOR]

Agile practices present one approach for firms to adapt to an increasingly dynamic and competitive environment. Although prior studies have investigated performance outcomes of agile projects, agile practices’ consequences on a project team's collaborative processes have not yet been thoroughly analyzed. It also remains unclear whether practices on a higher organizational level, such as project portfolio management (PPM), support or constrain agile practices’ benefits, especially if a firm simultaneously conducts traditionally managed and agile projects. Therefore, this article investigates the role of agile practices for a project's teamwork quality (TWQ) and project success and examines the influence of organizational contingencies. Specifically, we conceptually and empirically analyze the moderating impact of PPM practices on the relationship between agile practices, TWQ, and project success. A multi-informant analysis of 378 projects nested in 100 portfolios shows that agile practices positively relate to project success through TWQ. We find that traditional PPM practices such as business case existence, strategic clarity, and operational control constrain this relationship. Our article contributes to the literature on project teams and portfolio management by providing empirical insights on the interaction between project and portfolio management practices. [ABSTRACT FROM AUTHOR]

We discuss modeling in the context of agile software development and reflect on how we, as educators, can use modeling to help improve agile practices. [ABSTRACT FROM AUTHOR]

Large scale aerial deployment of miniature sensors in tough environmental conditions requires a deployment device that is lightweight, robust, and steerable. We present a novel samara-inspired autorotating craft that is capable of two flight modes (autorotating mode and diving mode) with an average glide angle of 28.9 $^{\circ }$ (1.81 m lateral distance per 1 m loss of altitude) in the former mode. The bidirectional transition between the two modes and directional control is achieved by using only a single actuator. Also, in order to minimize its glide angle, a design optimization methodology is presented for our prototype, diving samara autorotating wing, along with a new cyclic control strategy for directional control of autorotating descent. The dynamic model, simulated in a six degrees-of-freedom environment using the blade element theory, is integrated with genetic algorithm to derive parameters for the wing geometry, flap angle for autorotation, and the proposed cyclic control. The physical prototype autorotates at a descent velocity of 1.43 m/s and rotation speed 4.17 Hz, and is able to transit to diving mode in an average duration of 272 ms to increase its descent velocity by at least 17.6 times. At any point during the dive, it is able to transit back into autorotation in an average duration of 327 ms. Semioutdoor experiments were used to investigate the bidirectional transitions and verify the glide angle (28.9 $^{\circ }$), which is much improved from the previous prototype (SAW+, 58.4 $^{\circ }$). Lastly, as a demonstration of a real-life deployment scenario and environmental conditions, the prototypes were dropped from a fixed-wing unmanned aerial vehicle at a suburban test site. [ABSTRACT FROM AUTHOR]

Contribution: This article presents agile software engineers stick together (ASEST+), an improved version of a framework called ASEST that aims to develop team cohesion, leading to better team learning and software engineering student teams. Background: Effective teamwork is crucial for agile software development’s success and is, therefore, a key topic of current software engineering education. In the previous work, a preliminary proposal for ASEST+ was presented. Here, an improved version, more suitable for agile practice education and considering cohesion antecedents, is described. Intended Outcome: A teaching-learning framework to support teamwork in agile software education. Application Design: ASEST+ is built around Scrum teams and combines learning strategies to train students in collaborative and technical agile practices. ASEST+ establishes policies for role allocation and team rule agreements to regulate communication and address conflict management agile practices. ASEST+ addresses personality traits, conflict resolution, and task interdependence as the antecedents identified as the most important. Findings: A quasiexperiment showed that the use of ASEST+ significantly increases the students’ positive perceptions on team cohesion, team performance, and team learning compared with the control group. [ABSTRACT FROM AUTHOR]

A portable fast chirp frequency-modulated continuous-wave (FMCW) reflectometer is presented to locate and monitor fast varying discontinuities or faults on transmission lines. This frequency-domain reflectometry (FDR) approach exploits and adapts the advantages of the closely related and frequently employed FMCW radar principle to transmission line reflectometry and overcomes the limitations of commonly used time-domain reflectometry (TDR) methods. The signal generation is based on direct digital synthesis (DDS) and frequency multiplication in order to exploit the advantages of DDS technology, e.g., fast and agile sweep time, and to overcome the drawbacks of analog signal sources related to nonlinearities, temperature sensitivity, or phase noise. By this means, the presented reflectometer provides highly linear, broadband, and fast swept chirp pulses with a duration on the order of microseconds with an initial frequency in the lower UHF-band and a bandwidth of 5.2 GHz. The system concept, its hardware realization, and performance specifications are introduced. The first laboratory test results for static transmission lines and a dynamic measurement setup are presented. The results demonstrate the effectiveness, versatility, and fine ranging capabilities on the order of 2 cm of this approach. [ABSTRACT FROM AUTHOR]

In conventional hybrid beamforming approaches, the number of radio-frequency (RF) chains is the bottleneck on the achievable spatial multiplexing gain. Recent studies have overcome this limitation by increasing the update-rate of the RF beamformer. This paper presents a framework to design and evaluate such approaches, which we refer to as agile RF beamforming, from theoretical and practical points of view. In this context, we consider the impact of the number of RF-chains, phase shifters’ speed, and resolution to design agile RF beamformers. Our analysis and simulations indicate that even an RF-chain-free transmitter, which its beamformer has no RF-chains, can provide a promising performance compared with fully-digital systems and significantly outperform the conventional hybrid beamformers. Then, we show that the phase shifter’s limited switching speed can result in signal aliasing, in-band distortion, and out-of-band emissions. We introduce performance metrics and approaches to measure such effects and compare the performance of the proposed agile beamformers using the Gram-Schmidt orthogonalization process. Although this paper aims to present a generic framework for deploying agile RF beamformers, it also presents extensive performance evaluations in communication systems in terms of adjacent channel leakage ratio, sum-rate, power efficiency, error vector magnitude, and bit-error rates. [ABSTRACT FROM AUTHOR]

This article presents an ultralow-profile and lightweight Ku-band transmit phased array with 256 dual-polarized antenna elements for SATCOM on-the-move (SOTM) terminals. The antennas are placed in a square grid with λ/2 spacing at 14 GHz. At normal incidence, the phased array results in a measured effective isotropic radiated power (EIRP) of 64.5 and 66.5 dBm at P1~dB and Psat, respectively, per polarization. The measured patterns, in E- and H-planes, show almost ideal patterns with a wide scanning range of ±60°, a 3-dB instantaneous bandwidth of 13.0–14.6 GHz, and a cross-polarization isolation of 27 dB up to ±45° and 23 dB at ±60° scan angles. In the circular polarization mode, the measured axial ratio (AR) is <1.1 dB at 14–14.5 GHz. The phased array is also capable of synthesizing deep nulls (−30 to −40 dB) over a wide range of angles, thereby reducing unintended radiation to geostationary orbit (GEO) satellites. Transmit noise analysis is presented and shows that the array signal-to-noise ratio (SNR) is dominated by the block upconverter (BUC) and not by the beamformers. An error vector magnitude (EVM) of 2.8%–3.5% was achieved over a wide scan range for QPSK, 8-PSK, and 16-PSK waveforms with 100-MHz bandwidth. The array near-ideal performance, compact size, low profile with 3.5-mm thickness, and ultralightweight of 212 g make it ideal for affordable Ku-band SATCOM terminals. [ABSTRACT FROM AUTHOR]

This article presents a Ku-band phased-array receive tile with 256 elements. The design is based on 64 dual-polarized beamformer chips assembled on a printed circuit board (PCB) with dual-polarized antennas and an integrated Wilkinson combiner network and can operate at any polarization (linear, rotated-linear, and circular). The 256 elements are spaced 0.52λ apart at 12.7 GHz in the x- and y-directions. The measured patterns show near ideal patterns with a wide beam scanning range of ±70° (V- and H-pol) and a high cross-polarization rejection of 27 dB. The array has a 3-dB instantaneous scanning bandwidth of 10.6–12.5 GHz. In circular polarization mode, the measured axial ratio (AR) is 0.5 dB at 11.75 GHz for both left- and right-hand circular polarizations. The tile design is scalable to allow large-scale phased-array construction with 1024 elements or higher. Extensive measurements are presented, showing the versatility of this approach. Also, the dual-polarization feeds can be optimized to result in very low cross-polarization for circular and slanted-linear polarizations at all scan angles. The array performance, compact size, ultralightweight of 258 g, and low profile with 3.5-mm thickness make it suitable for affordable mobile Ku-band SATCOM on the move (SOTM) terminals. [ABSTRACT FROM AUTHOR]

End-to-end network slicing is a novel concept based on virtualization and softwarization technology that can efficiently address the problems of legacy networks. It can leverage agile physical and network layer adaptability, and foster optimal user and system performance. These features make end-to-end network slicing suitable for scenarios such as flash crowds and emergency situations. This article presents an end-to-end network slicing framework capable of addressing the demands of flash crowd and emergency scenarios. The article provides details about these scenarios, and it introduces an end-to-end agile, flexible, and scalable wireless system architecture consisting of softwarized components that can be orchestrated to fulfill the underlying system requirements. By addressing important key performance indicators with experimental measurements, the article demonstrates the applicability of our slicing framework for flash crowd scenarios. [ABSTRACT FROM AUTHOR]

Background: Although agile and Scrum have been important frameworks in software engineering for over a decade, little research has explored how teams use Scrum language within their sprints. Literature review: Most explorations of Scrum communication have been collected through self-reported means. These studies are inherently unable to explore how Scrum teams use Scrum-centric language in their meetings in ways that adhere or run counter to standard Scrum practice. Research questions: 1. In what ways is Scrum reflected in the language used by team members in various sprint meetings? 2. What associations exist between the job title of team members and their use of Scrum language? 3. What does a discourse analysis reveal about the ways in which this team uses language to value and discount Scrum? Research methodology: For three sprints over 10 weeks, I recorded meetings of 27 Scrum team members. I transcribed these meetings, developed a codebook for assigning Scrum language categories, conducted an interrater reliability agreement on the data, completed a correspondence analysis on how Scrum language associates with meeting types and job titles, and conducted a discourse analysis to determine in what ways these teams value and discount Scrum. Results/discussion: Scrum language was found in all recorded meetings across all three sprints, with much language found in the planning meetings. Few associations existed between Scrum language and job title, suggesting that Scrum at this engineering firm is an egalitarian process. In addition, the discourse analysis revealed that this engineering firm valued User Story and Sprint Execution language while discounting Capacity and Story Pointing language. Conclusions: Although this group broadly adheres to Scrum practices about 68% of the time, this study finds that several current standard components of Scrum are routinely discounted. This exploratory study suggests that more research into the in-situ use of Scrum language in engineering workplaces is necessary to better inform engineering professionals about the communicative expectations of Scrum and to better enable engineering communication educators to prepare future engineers for Scrum realities. [ABSTRACT FROM AUTHOR]

The Berkeley resilient out-of-order machine (BROOM) is a resilient, wide-voltage-range implementation of an open-source out-of-order (OoO) RISC-V processor implemented in an ASIC flow. A 28-nm test-chip contains a BOOM OoO core and a 1-MiB level-2 (L2) cache, enhanced with architectural error tolerance for low-voltage operation. It was implemented by using an agile design methodology, where the initial OoO architecture was transformed to perform well in a high-performance, low-leakage CMOS process, informed by synthesis, place, and route data by using foundry-provided standard-cell library and memory compiler. The two-person-team productivity was improved in part thanks to a number of open-source artifacts: The Chisel hardware construction language, the RISC-V instruction set architecture, the rocket-chip SoC generator, and the open-source BOOM core. The resulting chip, taped out using TSMC's 28-nm HPM process, runs at 1.0 GHz at 0.9 V, and is able to operate down to 0.47 V. [ABSTRACT FROM AUTHOR]

NFV is an emerging key technology that overcomes many challenges facing network service providers, such as reducing the capital and the operating expenses and satisfying the growing demand for mobile services. Integrating NFV with MEC and cloud environments requires an architecture that enables efficient implementations and deployments of NFV entities. Microservices architecture is a promising implementation of service-oriented architecture with recognized advantages in terms of modularity and continuous delivery. This article envisions microservices architecture as the solution of choice for building NFV platforms that are hosted in a dynamic environment ranging from MEC to cloud environments. This article addresses the major challenges and requirements of the microservices architecture to fully-exploit the potential of its adoption in NFV. It also proposes potential solutions that alleviate these issues. The article also discusses the need for agile and modular NFV entities along with MEC to realize various applications. To this end, the article discusses explicitly a novel NFV microservices entities scheduler optimization model. The proposed scheduler aims at minimizing network delays while taking into consideration various functional and non-functional constraints. The evaluation of the simulation results demonstrates that the proposed model minimizes the computational paths' latencies and improves the performance and availability of the NFV service chains. [ABSTRACT FROM AUTHOR]

This paper presents a robust virtual sensor to estimate the chassis planar motion states and the tire forces during agile maneuvers using a tire-model-less approach. Specifically, virtual sensing is achieved from standard sensor signals available on the CAN bus of modern vehicles using a modular filter architecture composed of stochastic Kalman filters. A high-fidelity virtual testing environment is constructed in IPG CarMaker using a driver-in-the-loop setup to verify the virtual sensor without compromising driver's safety. Moreover, road random profiles are incorporated into the virtual road to assess the state estimator robustness to high vertical excitation levels. The virtual sensor is simulated under drifting maneuvers performed by an experienced test driver and tested experimentally under Fishhook and Slalom maneuvers. Finally, the state estimator is integrated into a drift controller, and autonomous drift control using exclusively readily available measurements is verified for the first time. As the drift equilibrium depends strongly on the tire–road friction, an adaptive neurofuzzy inference system has been integrated into the virtual sensor structure to provide a continuous approximation of the road friction characteristics (axle lateral force versus slip curve) in rigid and loose surfaces. The findings suggest that it may be possible to develop advanced vehicle controllers without using a tire model. This can lead to a substantial acceleration of development time, particularly in off-road applications, and remove the need for online estimation of tire properties due to pressure, wear, and age. [ABSTRACT FROM AUTHOR]

Space information networks (SINs) have been designed to achieve agile acquisition, transmission, and processing of space information. Compared to traditional terrestrial communication networks comprised of mobile users and fixed resources, SINs are characterized by resource mobility, specifically in terms of resource migration, interchange, and aggregation. The resource mobility of SIN provides opportunities to deal with the resource scarcity problem. However, due to complex multi-dimensional resource mobility management, making full use of the opportunities brought by resource mobility is a daunting challenge for network performance improvement. This article provides an overview of open issues with regard to resource mobility in SINs. We first propose the concept of resource mobility and further elaborate on the opportunities it provides. Then we introduce the key research challenges of resource mobility management from three aspects. Furthermore, an optimal resource mobility utilization strategy is devised to achieve high network performance. Overall, resource mobility opens new niches for the exploitation of efficient resource utilization in SINs. [ABSTRACT FROM AUTHOR]

This paper investigates an agile confidential transmission strategy combining big data driven cluster and opportunistic beamforming (OBF) in the scenario where the same huge content is downloaded simultaneously by many users from the same base station. Instead of a burden from the traditional perspective, big data can be viewed as a resource. With the help of big data, data driven cluster taking into account security issues can be formed. Due to some obvious advantages, physical layer security (PHY-security) techniques as an alternative to the traditional high complexity cryptography-based secrecy methods are employed to achieve confidential transmission. For the purpose of superior secrecy performance, the scheme combining big data driven cluster and OBF, each of which can configure limited communication resources agilely and effectively in a dynamically changing network environment, is proposed. As the number of authorized users increases in the system, not only the channel vectors of cluster heads can tend to match with beamforming vectors with a high probability, but also more authorized users can be added into clusters and attain confidential content. These advantages ensure the combination of these two techniques is an attractive approach to transmit confidential message at a high rate. Based on different demand cases, multiple versions of the scheme combining cluster and OBF are put forward. In order to validate our proposed schemes, numerical simulations are carried out and the results show that a significant performance gain over both the average secrecy sum-capacity and the average number of authorized users accessing the system is achieved. [ABSTRACT FROM AUTHOR]

A design method for electrically controllable composite right/left-handed (CRLH) leaky-wave antennas (LWAs) with large beam-steering range employing liquid crystal (LC) in printed circuit board technology is proposed. It is demonstrated with detailed mathematical derivation that the design principle enables the LC-CRLH-LWA to keep the balanced condition with all bias states applied to the LC, yielding LC-CRLH-LWAs that feature a steady balanced condition and a broadband property. Based on this principle, an LC-CRLH-LWA prototype is designed, simulated, optimized, and experimentally validated. According to the simulation results, the designed LC-CRLH-LWA operates in the band from 11.14 to 12.77 GHz with a frequency-agile radiation direction. By tuning the permittivity of LC, the radiation direction of the designed antenna scans from −21° to +23° at the fixed operating frequency of 12.4 GHz. The experimental results agree well with the simulated data. Furthermore, sidelobe level suppression of the designed antenna is achieved through decreasing the reflection between the unit cells of the antenna. [ABSTRACT FROM AUTHOR]

Virtualization provides benefits for many workloads, but the overheads of virtualizing memory are still high. The cost comes from managing two levels of address translation--one in the guest virtual machine (VM) and the other in the host virtual machine monitor (VMM)--with either nested or shadow paging. This article introduces agile paging, which combines the best of both nested and shadow paging within a page walk and exceeds the performance of both techniques. [ABSTRACT FROM AUTHOR]

Multicarrier waveforms bring several major advantages over single carrier waveforms in radar systems: frequency diversity, waveform diversity, short time on target and the possibility to optimize the transmitted waveforms, to mention a few. Interesting waveform designs utilizing diversity have been proposed in the literature already. In this paper, we develop a generalized model that can accommodate a wide variety of design options, both existing and novel ones, in an easy and intuitive way. The developed matrix equations for transmitter and receiver allow for implementing different waveforms simply by filling in the elements to corresponding matrices accordingly. Moreover, intuitive agile generation of waveforms in simulation environments and in practice is facilitated. Waveform optimization examples are provided using the derived model. A Mutual Information based criterion is employed to formulate the optimization problems which are solved analytically. Novel multicarrier spread spectrum waveforms are proposed and generated using the derived model. The radar performance of one of these waveforms is investigated through simulations. It is demonstrated that it can outperform well-known existing multicarrier waveforms. It is also shown that such waveform can lower the peak-to-average-power ratio due to the spreading operation, which is a benefit for the front end designs of the transmitter and receiver. [ABSTRACT FROM AUTHOR]

Nowadays, considerable attention is paid to agile methods as a means to improve management of software development processes. The widespread use of such methods in professional contexts has encouraged their integration into software engineering training and undergraduate courses. Although several research efforts have focused on teaching Scrum through simulating a software development project, they covered only the learning of programming practices within a Scrum team. Furthermore, few studies tackle nontechnical skills other than the development practices themselves. The work presented here introduces an original Scrum-based training model enhanced with agile coaching to maximize student performance. This was validated by a case study on a capstone project in a Scrum course. This paper summarizes the positive results of introducing agile coaching, which resulted in approximately 22% more coverage of software engineering practices. In addition, a survey data showed that, compared to students who did not receive coaching, coached students gained valuable insight into the internalization of Scrum, problem solving, and guidance by means of checkpoint meetings. [ABSTRACT FROM AUTHOR]

Although traceability information is vital to many software engineering activities, agile development approaches rarely use it because of the extra effort required. In this industry case study, the authors report the results of applying their lightweight semiautomated method that integrates traceability into software architecture developed with an agile process like Scrum. [ABSTRACT FROM PUBLISHER]

The final phase of CMOS technology scaling provides continued increases in already vast transistor counts, but only minimal improvements in energy efficiency, thus requiring innovation in circuits and architectures. However, even huge teams are struggling to complete large, complex designs on schedule using traditional rigid development flows. This article presents an agile hardware development methodology, which the authors adopted for 11 RISC-V microprocessor tape-outs on modern 28-nm and 45-nm CMOS processes in the past five years. The authors discuss how this approach enabled small teams to build energy-efficient, cost-effective, and industry-competitive high-performance microprocessors in a matter of months. Their agile methodology relies on rapid iterative improvement of fabricatable prototypes using hardware generators written in Chisel, a new hardware description language embedded in a modern programming language. The parameterized generators construct highly customized systems based on the free, open, and extensible RISC-V platform. The authors present a case study of one such prototype featuring a RISC-V vector microprocessor integrated with a switched-capacitor DC-DC converter alongside an adaptive clock generator in a 28-nm, fully depleted silicon-on-insulator process. [ABSTRACT FROM AUTHOR]

Spectrally non-contiguous transmissions pose serious transceiver design challenges due to the nonlinear PA. When two or more non-contiguous carriers with close proximity are amplified by the same PA, spurious emissions inside or in the vicinity of the transmitter RF band are created. These spurious emissions may violate emission limits or otherwise compromise network coverage and reliability. Lowering the transmit power is a straightforward remedy, but it will reduce throughput, coverage, and power efficiency of the device. To improve linearity without sacrificing performance, several DPD techniques have recently been proposed to target the spurious emissions explicitly. These techniques are designed to minimize the computational and hardware complexity of DPD, thus making them better suited for mobile terminals and other lowcost devices. In this article, these recent advances in DPD for non-contiguous transmission scenarios are discussed, with a focus on mitigating the spurious emissions in the concrete example case of non-contiguous dual-carrier transmission. The techniques are compared to more traditional DPD approaches in terms of their computational and hardware complexities, as well as linearization performance. [ABSTRACT FROM AUTHOR]

A variety of visualization guidelines, principles, and techniques are available to help create a visualization-based dashboard, but few publications discuss the experience of designing dashboards in the real world. This article discuss the lessons learned from designing applications for small start-up companies and institutions. From their experience as visualization practitioners, the authors confirm the need for tailored and customizable approaches, emphasize the need for a quicker way to create functional prototypes, point out frequent misconceptions on the scope of a functional prototype, discuss how performance can affect prototyping, and discuss the resistance of industrial partners to involve their customers in requirements gathering. [ABSTRACT FROM AUTHOR]

The capacity to reflect on past practice is important for continuous learning in software development. Reflection often takes place in cycles of experience followed by conscious application of learning from that experience, during which a software developer might explore comparisons, ponder alternatives, take diverse perspectives, and draw inferences, especially in new and/or complex situations. Such reflective practice has been shown in different disciplines to be an effective developmental practice for organizations, for teams, and for individuals. The guest editors of this special issue on reflection describe the concept in general and the selected articles in particular. [ABSTRACT FROM PUBLISHER]

The theoretical underpinnings of agile principles emphasize regular reflection as a means to attain a sustainable development pace and continuous learning. In practice, high iteration pressure can diminish opportunities for ongoing learning and reflection threatening to deprive software teams of learning and reflection and possibly stagnating process evolution. The Reflective Agile Learning Model (REALM) combines insights and results from studies of agile development practices in India, New Zealand, and the US with Schön's theory of reflective practice. Using REALM, agile teams can establish self-organized learning as well as regular process maintenance and opportunities for process evolution to continuously improve practice. [ABSTRACT FROM PUBLISHER]

It was May 2010 when my "call for insights" first appeared in this magazine. For nearly four years, you, gentle readers, have responded to that call and have shared your experiences, challenges, and learnings. I appreciate all of you who submitted, who revised and responded to shepherding, but especially, all who stayed the course and produced a published article. This article is my farewell to the series, but it will continue on even though I'm no longer steering it. If you haven't yet submitted something for publication, I encourage you to do that. We need to hear your insights! [ABSTRACT FROM PUBLISHER]

Developers of embedded systems are driven to constantly improve product quality, reduce cost, and rapidly deliver reliable working code. The embedded software domain applies constraints which can hinder agile methodologies commonly used to achieve such benefits. Simulation-based software development is one proven method that addresses these constraints. When tailored to work in conjunction with agile principles, simulation centric development facilitates meeting product goals. In this article, the authors discuss techniques for leveraging software-in-simulation (SiS) in conjunction with agile methodologies, and illustrate how combining agile with SiS contributes to gaining more benefit from agile practices and facilitates better software development. [ABSTRACT FROM PUBLISHER]

The SATURN Conference is an international forum for software engineers and anyone else interested in software architecture. SATURN regularly partners with IEEE Software, a relationship that continues to offer strong content on both sides. [ABSTRACT FROM PUBLISHER]

The challenges issued by next-generation mobile communication scenarios clearly emphasize the inadequacy of traditional communication solutions in supporting efficient mobile and pervasive applications. Research so far has focused on higher-layer middleware or on the optimization of TCP-based solutions for wireless environments, but there's an obvious need to focus on communication middleware that can provide the right set of concepts and tools to support future applications. [ABSTRACT FROM PUBLISHER]

Agility without objective governance cannot scale, and governance without agility cannot compete. Agile methods are mainstream, and software enterprises are adopting these practices in diverse delivery contexts and at enterprise scale. IBM's broad industry experience with agile transformations and deep internal know-how point to two key principles to deliver sustained improvements in software business outcomes with higher confidence: measure and streamline change costs, and steer with economic governance and Bayesian analytics. Applying these two principles in context is the crux of measured improvement in continuous delivery of smarter software-intensive systems. This article describes more meaningful measurement and prediction foundations for economic governance. The Web extra at http://youtu.be/ghAM8ifyeVI is a video in which Walker Royce, author, IEEE Software editorial board member, and IBM Chief Software Economist, describes how to reason about software delivery governance with lean principles. [ABSTRACT FROM AUTHOR]

Usually we read about agile development practices that seem like no more than hand waving. If that's how you feel, you'll enjoy traveling this detailed design journey and seeing up close how test-driven development (TDD) and refactoring are done in an agile environment. This article is especially insightful because of the collaborative shepherding by Rebecca Wirfs-Brock. [ABSTRACT FROM AUTHOR]

Agile processes seek "just enough" requirements. However, this focus on simple software solutions can come at the expense of solutions that meet more creative requirements. To explore alternatives, this article reports results from extending one agile process with creativity techniques in a project for a large media organization. Domain experts ranked the requirements generated with the process as more novel than baseline epics from the product backlog of the same project, while the requirements' usefulness increased overall after incubation over the duration of a sprint. [ABSTRACT FROM PUBLISHER]

This paper provides a systematic meta-analysis of 27 studies that investigate the impact of Test-Driven Development (TDD) on external code quality and productivity. The results indicate that, in general, TDD has a small positive effect on quality but little to no discernible effect on productivity. However, subgroup analysis has found both the quality improvement and the productivity drop to be much larger in industrial studies in comparison with academic studies. A larger drop of productivity was found in studies where the difference in test effort between the TDD and the control group's process was significant. A larger improvement in quality was also found in the academic studies when the difference in test effort is substantial; however, no conclusion could be derived regarding the industrial studies due to the lack of data. Finally, the influence of developer experience and task size as moderator variables was investigated, and a statistically significant positive correlation was found between task size and the magnitude of the improvement in quality. [ABSTRACT FROM AUTHOR]

A personal narrative is presented which explores the author's experience of training people about agile software development through storytelling in presentations. The article further discusses guidelines for crafting a story by discussing two stories entitled "The Castle Fairy Tale" and "A Soviet Economist in Rotterdam." Information about the author of the article is also presented. INSETS: CRAFTING A STORY: GUIDELINES FOR DOING IT YOURSELF;EXAMPLE 1: THE CASTLE FAIRY TALE;EXAMPLE 2: A SOVIET ECONOMIST IN ROTTERDAM.

Self-organizing teams have been recognized and studied in various forms—as autonomous groups in socio-technical systems, enablers of organizational theories, agents of knowledge management, and as examples of complex-adaptive systems. Over the last decade, self-organizing teams have taken center stage in software engineering when they were incorporated as a hallmark of Agile methods. Despite the long and rich history of self-organizing teams and their recent popularity with Agile methods, there has been little research on the topic within software wngineering. Particularly, there is a dearth of research on how Agile teams organize themselves in practice. Through a Grounded Theory research involving 58 Agile practitioners from 23 software organizations in New Zealand and India over a period of four years, we identified informal, implicit, transient, and spontaneous roles that make Agile teams self-organizing. These roles—Mentor, Coordinator, Translator, Champion, Promoter, and Terminator—are focused toward providing initial guidance and encouraging continued adherence to Agile methods, effectively managing customer expectations and coordinating customer collaboration, securing and sustaining senior management support, and identifying and removing team members threatening the self-organizing ability of the team. Understanding these roles will help software development teams and their managers better comprehend and execute their roles and responsibilities as a self-organizing team. [ABSTRACT FROM AUTHOR]

Agile teams create business value by responding to changing business environments and delivering working software at regular intervals. While doing so, they make design tradeoffs to satisfy business needs such as meeting a release schedule. Technical debt is the result of such decisions or tradeoffs. When this happens, agile teams must pay off the accumulated debt by improving designs during subsequent iterations in order to improve maintainability. This must happen in a systematic way so that technical debt does not swell up and damage the project. Accomplishing this is one of the major challenges in distributed agile projects. The scope of technical debt in software projects is spread across all areas including architecture, design, code, and test scripts. [ABSTRACT FROM PUBLISHER]

Several approaches that could be implemented on any platform via any methodology would greatly increase the odds of the successful deployment of a working information system. [ABSTRACT FROM PUBLISHER]

Proponents of various processes and methods in the agile and lean communities have made many bold claims about usefulness, but those claims are rarely supported by empirical investigations. Data gathered from more than 12,000 work items collected over two years sheds light on Kanban versus Scrum.To acquire more knowledge about the performance of different agile or lean methods, scholars should conduct similar studies in different organizations in different application domains and with people of different cultures and competences. [ABSTRACT FROM PUBLISHER]