Agile Applications Research Articles

Robust State/Output-Feedback Control of Coaxial-Rotor MAVs Based on Adaptive NN Approach.

The coaxial-rotor micro-aerial vehicles (CRMAVs) have been proven to be a powerful tool in forming small and agile manned-unmanned hybrid applications. However, the operation of them is usually subject to unpredictable time-varying aerodynamic disturbances and model uncertainties. In this paper, an adaptive robust controller based on a neural network (NN) approach is proposed to reject such perturbations and track both the desired position and orientation trajectories. A complete dynamic model of a CRMAV is first constructed. When all system states are assumed to be available, an NN-based state-feedback controller is proposed through feedback linearization and Lyapunov analysis. Furthermore, to overcome the practical challenge that certain states are not measurable, a high-gain observer is introduced to estimate the unavailable states, and then, an output-feedback controller is developed. Rigorous theoretical analysis verifies the stability of the entire closed-loop system. In addition, extensive simulation studies are conducted to validate the feasibility of the proposed scheme.

Recent advances in cloud data centers toward fog data centers

Recent advances in cloud data centers toward fog data centers

A Capacitive Loading Method for Turning a Single-Band Antenna Into Dual-Band for Wireless Terminal Applications

This letter proposes a simple method to turn a single-band inverted-F antenna (IFA) or loop antenna into a dual-band antenna with a small frequency ratio and similar radiation patterns by simply adding a capacitor near the shorting end of a conventional single-band IFA or a loop antenna. Two demonstration examples imitating a mobile terminal application using IFA and loop antenna are present. The measured results show that the IFA and loop antenna with an added capacitor near the shorting end have comparable radiation patterns and total efficiencies in the two designed frequency bands compared with the antennas without the capacitor. The measured frequency ratio of the two resonances is 1.15 (2.23 and 2.56 GHz) for IFA and 1.19 (2.19 and 2.61 GHz) for loop antenna. And the two resonant frequencies can be easily controlled by tuning the added capacitor so that this method can be easily applied to frequency agility applications. To illustrate the physical mechanism, a transmission line model is presented and analyzed.

Integrating design thinking into extreme programming

The increased demand for information systems drives businesses to rethink their customer needs to a greater extent and undertake innovation to compete in the marketplace. The design thinking (DT) is a human-centered methodology leads to creativity and innovation. The agile applications development such as extreme programming (XP) as a rapid application development approach tends to focus on perfecting functionality requirement and technical implementation. However, it causes significant challenges to building software/applications to meet the needs of end-user. This study integrates DT practices into XP methodology to improve the quality of software product for the end-users and enable businesses to achieve creativity and innovation. The proposed integrated DT@XP framework presents the various DT practices (empathy, define, persona, DT user stories) are adapted into XP exploration phase, prototyping and usability evaluation into XP planning phase. Our work demonstrates the applicability of DT concepts to analyze customer/user involvement in XP projects.

Power Control in UAV-Supported Ultra Dense Networks: Communications, Caching, and Energy Transfer

By means of network densification, ultra dense networks (UDNs) can efficiently broaden the network coverage and enhance the system throughput. In parallel, unmanned aerial vehicles (UAVs) communications and networking have attracted increasing attention recently due to their high agility and numerous applications. In this article, we present a vision of UAV-supported UDNs. Firstly, we present four representative scenarios to show the broad applications of UAV-supported UDNs in communications, caching and energy transfer. Then, we highlight the efficient power control in UAV-supported UDNs by discussing the main design considerations and methods in a comprehensive manner. Furthermore, we demonstrate the performance superiority of UAV-supported UDNs via case study simulations, compared to traditional fixed infrastructure based networks. In addition, we discuss the dominating technical challenges and open issues ahead.

Structuring the Federation of Cloud Service for Big Data

The demand for agile and flexible business application for big data has sparked interest in using cloud computing technology. Due to the limitation of provider’s capability and the magnanimity of task quantity for big data, a single cloud provider may not offer enough service resources. However, a service federation among multiple providers can effectively solve this problem. This paper proposes the framework of cloud federation and introduces the basic processes of building service federation among multiple cloud providers. Moreover, we propose a multiobjectives task assigning model in the federation. A genetic algorithm based heuristic approach is developed as the optimization method. Eventually, some simulation experiments are conducted to illustrate the effectiveness of the model.

Repairing the teaching of contempt: Jules Isaac’s contribution to Jewish-Catholic relations

This paper surveys and evaluates the contribution of Jules Isaac to the reorientation of relations between Christians and Jews. Jules Isaac, French educator, historian and bureaucrat committed his life to the repair of relations between Christians and Jews. He played a pivotal role in promoting consideration of Jews and Judaism at the Second Vatican Council. His life and career, while little known or appreciated by religious educators in the English-speaking world, reveal how an agile application of committed diplomacy, critical intellectual endeavour and cooperation across religious boundaries contributed to an increase in Christian self-understanding and a revitalised approach to interreligious relations. The work of religious educators is indebted to the life and career of Jules Isaac.

Manipulating line waves in flat graphene for agile terahertz applications

AbstractReducing open waveguides enabled by surface waves, such as surface plasmon polaritons, to a one-dimensional line is attractive due to the potentially enhanced control over light confinement and transport. This was recently shown to be possible by simply interfacing two co-planar surfaces with complementary surface impedances, which support transverse-magnetic and transverse-electric modes, respectively. Attractively, the resultant “line wave” at the interface line features singular field enhancement and robust direction-dependent polarizations. Current implementations, however, are limited to microwave frequencies and have fixed functionality due to the lack of dynamic control. In this article, we examine the potential of using gate-tunable graphene sheets for supporting line waves in the terahertz regime and propose an adequate graphene-metasurface configuration for operation at room temperature and low voltage conditions. In addition, we show the occurrence of quasi-line wave under certain conditions of non-complementary boundaries and qualify the degradation in line wave confinement due to dissipation losses. Furthermore, we show the possibility to alter the orientation of the line wave’s spin angular momentum on demand unlike conventional surface waves. Our results on active manipulation of electromagnetic line waves in graphene could be useful for various applications including reconfigurable integrated circuits, modulation, sensing and signal processes.

Contemporary Progression, Agile Applications and Impending Scope of Internet of Things

International Journal of Computer Sciences and Engineering (A UGC Approved and indexed with DOI, ICI and Approved, DPI Digital Library) is one of the leading and growing open access, peer-reviewed, monthly, and scientific research journal for scientists, engineers, research scholars, and academicians, which gains a foothold in Asia and opens to the world, aims to publish original, theoretical and practical advances in Computer Science,Information Technology, Engineering (Software, Mechanical, Civil, Electronics & Electrical), and all interdisciplinary streams of Computing Sciences. It intends to disseminate original, scientific, theoretical or applied research in the field of Computer Sciences and allied fields. It provides a platform for publishing results and research with a strong empirical component. It aims to bridge the significant gap between research and practice by promoting the publication of original, novel, industry-relevant research.

Building open source security into agile application builds

Open source software offers many benefits, not least of which is the way that readily available software components and libraries can speed development. By not having to constantly reinvent the wheel, developers are able to adopt agile development methods that are adaptive, responsive – and fast. But there's also a risk involved. Using open source software offers many benefits and can speed development. But there are risks involved. Changes to applications are being made so quickly and so often that it is difficult to understand and review them for risk. And application development and security practices often appear to be at odds. To employ open source components safely, organisations need visibility into which components they're using. Tim Mackey of Black Duck by Synopsys examines how DevOps teams can utilise automated software composition analysis (SCA).

The Development, Validation, and Practical Application of an Employee Agility and Resilience Measure to Facilitate Organizational Change

Traditional change management approaches that focus on linear models and top-down control have proved less than adequate in addressing organizational change within the complexity and speed of today's unprecedented change. Researchers have suggested that by developing greater workforce agility, companies may be better positioned to manage or moderate rapid change and use this capability as a competitive advantage. Complementing current strategies with a different approach to managing change focused on individual agility and resilience may be a first step. This article focuses on the development, validation, and practical application of an employee agility and resilience measurement scale as part of a program in support of an alternative approach to managing organizational change. Results indicate that focusing on individual agility and resilience can prepare employees to handle uncertainty more successfully by adapting to change quicker and managing stress more effectively.

WISeR

Mashups are agile applications that aggregate RESTful services, developed by third parties, whose functions are exposed as Web Application Program Interfaces (APIs) within public repositories. From mashups developers’ viewpoint, Web API search may benefit from selection criteria that combine several dimensions used to describe the APIs, such as categories, tags, and technical features (e.g., protocols and data formats). Nevertheless, other dimensions might be fruitfully exploited to support Web API search. Among them, past API usage experiences by other developers may be used to suggest the right APIs for a target application. Past experiences might emerge from the co-occurrence of Web APIs in the same mashups. Ratings assigned by developers after using the Web APIs to create their own mashups or after using mashups developed by others can be considered as well. This article aims to advance the current state of the art for Web API search and ranking from mashups developers’ point of view, by addressing two key issues: multi-dimensional modeling and multi-dimensional framework for selection. The model for Web API characterization embraces multiple descriptive dimensions, by considering several public repositories, that focus on different and only partially overlapping dimensions. The proposed Web API selection framework, called WISeR (Web apI Search and Ranking), is based on functions devoted to developers to exploit the multi-dimensional descriptions, in order to enhance the identification of candidate Web APIs to be proposed, according to the given requirements. Furthermore, WISeR adapts to changes that occur during the Web API selection and mashup development, by revising the dimensional attributes in order to conform to developers’ preferences and constraints. We also present an experimental evaluation of the framework.

Reconfigurable Bandstop and Bandpass Filters With Wideband Balun Using IPD Technology for Frequency Agile Applications

A tunable bandstop filter (BSF) with a wideband balun using integrated passive devices (IPDs) technology for multichip module is proposed. The compact tunable BSF uses barium strontium titanate (BST) varactors demonstrating a tuning range of 55% from 1.3 to 2.3 GHz with a 20-dB rejection level. The performance of the filter is optimized by applying asynchronous biases to the BST varactors, leading to bandwidth and rejection level improvement. High-power test results show that the filter exhibits a third-order input intercept point of more than 40 dBm. An IPD wideband balun (0.5–2.5 GHz with ±1 dB amplitude imbalance and 180° ± 20°) using a wideband phase inverter is also presented. The design considerations of the wideband phase inverter (1.5–8 GHz) are addressed in this paper. Design and measured results are also presented for a fixed IPD bandpass filter, and an IPD bandpass filter with a tunable transmission zero to demonstrate the reconfigurability in frequency agile applications.

Development of a low-cost, low micro-vibration CMG for small agile satellite applications

The agility of the spacecraft which refers to the spacecraft's ability to execute fast and accurate manoeuvers within a fixed period of time, is a key satellite parameter. The spacecraft' s agility is directly proportional to the spacecraft actuators' output torque. For high torque inertial actuators (>0.5Nm), Control Moment Gyroscope (CMG) exhibits better performances in terms of mass and electrical power consumption than reaction wheels. However, in addition to the complex steering law required to avoid CMG singularities, one of the reasons why CMGs are not widely used is also due to their high micro-vibration emission which may interfere and disrupt the spacecraft' s sensitive instruments such as optical payloads. In this paper, an innovative two-stage viscoelastic isolation system has been designed and implemented in a new low micro-vibration CMG prototype. The first stage of the damping system acts at bearing level to attenuate the possible shock vibrations while the second stage acts at mechanism level to attenuate the structural resonances and motor noise. The developed CMG enables to combine high actuator output torque with a low micro-vibration signature. The viscoelastic damping system is cost effective as it is a fully passive system which requires no thermal control and no electronics. Furthermore, the attenuation provided by this innovative two stage damping system can reach a slope up to −80dB/dec which leads to a Mini-CMG micro-vibration signature lower than similar output torque reaction wheels not equipped with a damping system.

Tunable sound transmission at an impedance-mismatched fluidic interface assisted by a composite waveguide.

We report a composite waveguide fabricated by attaching a coupling aperture to a waveguide. The acoustic impedance of the composite waveguide can be regulated by merely controlling its coupling vibrations, depending on its structure size. By changing the size to adjust the acoustic impedance of the composite waveguide at an impedance-mismatched fluidic interface, tunable sound transmission at the desired frequencies is achieved. The reported composite waveguide provides a new method for sound regulation at a mismatched fluidic interface and has extensive frequency hopping and frequency agility applications in air-water sound communication.

The Role of Organizational Agility and Transformational Leadership in Service Recovery Prediction

Abstract The main goal of this research was to develop a conceptual model for defining the relationship between organizational agility and transformational leadership in personnel service recovery among governmental organizations. Due to the role of service recovery in customer satisfaction, previous researches have been focused on different factors leading to better service recovery. Due to its interwoven relationship with organizational flexibility and transformational leadership (with its supportive role) as well as with service recovery, organizational agility can play an eminent role in this process. Present research was on the basis 149 randomly-selected personnel; the findings indicated that (1) transformational leadership and (2) organizational agility have positive impact on service recovery. Moreover the findings indicated that suitable application of organizational agility and transformational leadership may lead the organization to better and suitable service recovery. The mutual role of these two factors can help managers in governmental organizations to pay more attention to the leadership styles applied in these organizations.

Edge caching with mobility prediction in virtualized LTE mobile networks

Mobile Edge Computing enables the deployment of services, applications, content storage and processing in close proximity to mobile end users. This highly distributed computing environment can be used to provide ultra-low latency, precise positional awareness and agile applications, which could significantly improve user experience. In order to achieve this, it is necessary to consider next-generation paradigms such as Information-Centric Networking and Cloud Computing, integrated with the upcoming 5th Generation networking access. A cohesive end-to-end architecture is proposed, fully exploiting Information-Centric Networking together with the Mobile Follow-Me Cloud approach, for enhancing the migration of content-caches located at the edge of cloudified mobile networks. The chosen content-relocation algorithm attains content-availability improvements of up to 500% when a mobile user performs a request and compared against other existing solutions. The performed evaluation considers a realistic core-network, with functional and non-functional measurements, including the deployment of the entire system, computation and allocation/migration of resources. The achieved results reveal that the proposed architecture is beneficial not only from the users’ perspective but also from the providers point-of-view, which may be able to optimize their resources and reach significant bandwidth savings.

The agile data modelling & design thinking approach to information system requirements analysis

Requirements analysis is an integral part of the development of Information Systems, and is essential to ensure that the system delivers the expected benefits. However, it is not a straightforward process, and the fact that Information Systems are used by humans introduces the human factors of complexity and unpredictability. This paper puts forward a requirements analysis process which involves the application of agile and design thinking to business oriented data modelling.

Ba0.6Sr0.4TiO3 thick film derived by polymer modified MOSD route for tunable microstrip antenna applications

ABSTRACTFrequency and phase agile microstrip antenna applications require relatively thick Barium Strontium Titanate (BST) films for good tunability. In this work, Polymer (PEG-200) modified MOSD process route is developed to produce cracks free (Ba0.6, Sr0.4) TiO3 Thick film on Low loss ST-X quartz substrate. Structural and electrical characteristics of the deposited films were investigated using Atomic Force Microscope, X-Ray Diffraction, C-V and C-F characterizations. XRD characterization conformed the single BST phase with polycrystalline nature of the film. AFM analysis depicted equiaxed shaped grains with average grain size and roughness of 120 nm and 4.15 nm respectively. Dielectric tunability, dielectric constant and loss tangent of the deposited films were 36.46%, 310 and 0.0213 respectively at 1 MHz frequency using MIM capacitive structure where conductive oxide LNO was used as bottom electrode. The applicability of polymer modified BST thick films over low loss substrate as composite substrate for tunable microstrip antenna applications at microwave frequency was demonstrated by design, fabrication and testing of a compact frequency tunable microstrip antenna in coplanar configuration. The tunability exhibited at X band frequency proves the suitability of developed processed route for tunable antenna applications.

A Taxonomy-based Approach For Fault Localization In Service-Oriented Applications

Service Oriented Computing is a relevant paradigm that allows for building software solutions as it supports the creation of dynamic and agile applications. As a result of these benefits, applications based on the paradigm are commonly used in the industry. However, the more complex software solutions become, the higher the chance of having bugs is. Identifying them in the entire solution may also be one of the most tedious, expensive and time-consuming activity within the developing process. Therefore, fault localization aims at finding the location of faults, determining the root cause of the failure and identifying the causes of abnormal behavior of a faulty program. In particular, fault localization for service oriented applications is currently a research field that has received little attention. In this context, we present a taxonomy-based approach for fault localization in service oriented applications, using information of faults in the underlying architecture of these applications, namely SOA. The results on the location of faults are not only provided to the developer but also enhanced with architectural information, that is, showing the faults and their connection with exceptions, code and architectural scenarios. The experimental results carried out indicate that developers reduce their effort of localizing faults in terms of time and lines of code.