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Project complexity is becoming increasingly challenging for project managers. Much valuable research has been done on the concept of project complexity. The research reported in this paper aims to provide a new means (the “Complexity Navigation Window”) and guiding principles for the navigation of project complexity in practice.

This paper applied action design research (a methodology for design science research) to design and evaluate the Complexity Navigation Window (CNW), which will serve as a representation of project complexity as a key component of the user interface for a decision support system (DSS) for managing project complexity.

Formative evaluations of the CNW by 16 project management practitioners indicated that the artefact is relevant, comprehensible and heading in a promising direction to guide decision-making. The evaluation also highlighted project managers' difficulty in using the (conceptual) representation by itself to assess a project's current situation accurately, which in turn limits their ability to understand a project's current complexity and decide an appropriate course of strategy. A conceptual framework by itself is insufficient. This finding motivates further research to develop and evaluate a DSS that would partially automate the assessment process (by surveying stakeholders and automatically assessing and representing project complexity according to the CNW), which should aid in increasing the accuracy (and timeliness) of project complexity assessments and contribute to appropriate strategy formulation and timely revision.

The formative evaluation of the CNW indicates relevance for practitioners and the further features of the DSS may still yield even higher perceived utility from the full artefact.

The paper provides improved understanding of practitioners' perceptions of project complexity and ability to assess it for a given project. The paper describes the design of a new visualisation for navigating and managing complexity. The paper further presents four strategies for managing project complexity. Finally, the paper also provides a methodological discussion on the potential of ADR in advancing project management research.

X-ray pulsar navigation (XPNAV) is an autonomous celestial navigation technology for deep space missions. The error in the pulse time of arrival used in pulsar navigation is large for various practical reasons and thus greatly reduces the navigation accuracy of spacecraft near the Earth and in deep space. This paper aims to propose a novel method based on ranging information that improves the performance of XPNAV.

This method replaces one pulsar observation with a satellite observation. The ranging information is the difference between the absolute distance of the satellite relative to the spacecraft and the estimated distance of the satellite relative to the spacecraft. The proposed method improves the accuracy of XPNAV by combining the ranging information with the observation data of two pulsars.

The simulation results show that the proposed method greatly improves the XPNAV accuracy by 70% compared with the conventional navigation method that combines the observations of three pulsars. This research also shows that a larger angle between the orbital plane of the satellite and that of the spacecraft provides higher navigation accuracy. In addition, a greater orbital altitude difference implies higher navigation accuracy. The position error and ranging error of the satellite have approximately linear relationships with the navigation accuracy.

The novelty of this study is that the satellite ranging information is integrated into the pulsar navigation by using mathematical geometry.

The purpose of this paper is to present a detailed plan of research on the information architecture of digital library websites.

The research plan was prepared on the basis of a critical analysis of the scientific literature concerning the areas and criteria for the analysis and evaluation of the information architecture of digital resources. The evaluation criteria selected in individual areas of information architecture and the entire evaluation model were tested on the example of Europeana. The study proposes criteria for all areas of information architecture: service identity, organizational system, labeling system and navigation system.

The proposed research model containing areas and criteria for assessing usefulness from the point of view of information architecture may complement the methodology for assessing digital libraries. In a structured manner, it presents areas important for building good digital resources together with criteria for heuristic evaluation. This thesis is confirmed by a study conducted on the example of Europeana.

For a more precise assessment of quality, you can add to the proposed criteria related to the information architecture the criteria proposed by Nielsen or other authors. These include, e.g. help users recognize, diagnose and recover from errors, result relevance, consistency of terminology and specific action conventions and an appropriate visual presentation.

The model can be used to assess the quality of websites of various digital libraries.

The methodology of assessing the quality of digital libraries is in the stage of formation and development. Such studies can apply evaluation criteria prepared to analyze all kinds of information systems and most of all web pages. At the beginning of the 21st century, concepts of using information architecture principles to design and evaluate digital libraries’ usability began to take shape. However, no detailed criteria for evaluating digital libraries based on the principles of information architecture have been presented.

The federated filter created by Carlson has been widely used in multi-sensor integrated navigation. Compared with no-reset federated filter, the reset mode has greater sub-filters’ performance, but faults of any subsystem would affect other healthy subsystems via global fusion and the sub-optimality of sub-filters’ estimation has influence on fault detection sensitivity. It’s a challenge to design a robust reset federated filter.

The time-varying observation noise is designed to reduce proportions of observation information in faulty sub-filters. A new dynamic information distribution algorithm based on optimal residual chi-square detection function is presented to reduce proportions of faulty sub-filters’ estimation in information fusion filter.

The robust filtering algorithm represents a filtering strategy for reset federated filter. Compared with fault isolation, the navigation result is smoother by using this algorithm. It has significant benefits in avoiding faulty sensors’ contamination and the performance of federated filter is greatly improved.

The approach described in this paper provides a new method to deal with federated reset filter’s faulty problems. This new robust federated filter algorithm possesses a great potential for various applications.

The approach described in this paper can be used in multi-sensor integrated navigation with no fewer than three sensors.

Compared with conventional approach of fault isolation, the proposed algorithm does not destroy the continuity and integrity of the filtering process. It improves the performance of the federated filter by reducing proportions of faulty observation information. It also reduces the influence of sub-optimality on fault detection sensitivity.

This paper aims to improve the performance of the autonomous optical navigation using relativistic perturbation of starlight, which is a promising technique for future space missions. Through measuring the change in inter-star angle due to the stellar aberration and the gravitational deflection of light with space-based optical instruments, the position and velocity vectors of the spacecraft can be estimated iteratively.

To enhance the navigation performance, an integrated optical navigation (ION) method based on the fusion of both the inter-star angle and the inter-satellite line-of-sight measurements is presented. A Q-learning extended Kalman filter (QLEKF) is designed to optimize the state estimate.

Simulations illustrate that the integrated optical navigation outperforms the existing method using only inter-star angle measurement. Moreover, the QLEKF is superior to the traditional extended Kalman filter in navigation accuracy.

A novel ION method is presented, and an effective QLEKF algorithm is designed for information fusion.

Electronic texts are an essential component of any e‐learning environment. This paper extends previous research on navigation and learning with electronic texts by examining the effects of a novel approach to navigation: allowing the learner to create their own navigation aids. We present two experimental studies investigating the effects of creating versus using A‐Z indexes and graphical maps on knowledge development and feelings of ownership for learning. Findings revealed that using a graphical map for navigation has advantages for knowledge development and for feelings of ownership, whereas creating a graphical map offers no significant benefits over plain hypertext; there were no benefits to using or creating A‐Z indexes over plain hypertext. It was also found in comparisons of using vs. creating graphical maps that high feelings of ownership were correlated with higher quality knowledge development. These findings have three major implications for designers of e‐learning environments: including graphical map navigation aids should be considered; designers should not assume that allowing learners to create their own navigation aids will improve learning; feelings of ownership for learning should be encouraged in learners.

The purpose of this paper is to present the development of hardware‐in‐the‐loop simulation (HILS) for visual target tracking of an octorotor unmanned aerial vehicle (UAV) with onboard computer vision.

HILS for visual target tracking of an octorotor UAV is developed by integrating real embedded computer vision hardware and camera to software simulation of the UAV dynamics, flight control and navigation systems run on Simulink. Visualization of the visual target tracking is developed using FlightGear. The computer vision system is used to recognize and track a moving target using feature correlation between captured scene images and object images stored in the database. Features of the captured images are extracted using speed‐up robust feature (SURF) algorithm, and subsequently matched with features extracted from object image using fast library for approximate nearest neighbor (FLANN) algorithm. Kalman filter is applied to predict the position of the moving target on image plane. The integrated HILS environment is developed to allow real‐time testing and evaluation of onboard embedded computer vision for UAV's visual target tracking.

Utilization of HILS is found to be useful in evaluating functionality and performance of the real machine vision software and hardware prior to its operation in a flight test. Integrating computer vision with UAV enables the construction of an unmanned system with the capability of tracking a moving object.

HILS for visual target tracking of UAV described in this paper could be applied in practice to minimize trial and error in various parameters tuning of the machine vision algorithm as well as of the autopilot and navigation system. It also could reduce development costs, in addition to reducing the risk of crashing the UAV in a flight test.

A HILS integrated environment for octorotor UAV's visual target tracking for real‐time testing and evaluation of onboard computer vision is proposed. Another contribution involves implementation of SURF, FLANN, and Kalman filter algorithms on an onboard embedded PC and its integration with navigation and flight control systems which enables the UAV to track a moving object.

A marketing‐centric view of the connected enterprise implies that qualitative information in its systems and general document structures share a marketing‐based vocabulary – we propose that this should be founded on POSIT. As any system needs to be accessed and understood by people, the basis of its construction and navigation principles should be transparent even though many component processes will be automated. Based on the use of natural language, a user‐defined glossary stems from a selection of primitives and relationships between them. Semantic mapping employing the reciprocal text‐to‐graphical capability of EXPRESS and EXPRESS G is outlined. The significance of XML and related developments is introduced in the context of qualitative information search and extraction from documents. Consensual language also aids connectivity of intranets and extranets to the Internet.

FEW branches of science or technology have made such rapid strides since the Second World War as inertial navigation. Although the principles of measuring vehicle acceleration and performing successive integrations to obtain velocity and distance travelled from a known starting point are as old as Newton's laws of motion, it is only within the last twenty years or so that precision engineering has developed to the stage where the requisite component accuracy could be obtained. Milestones along the route to the general application of inertial techniques to missiles, spacecraft and aircraft were the appreciation of Schuler tuning (1923), the use of a rudimentary guidance system with single‐axis integrating accelero‐meters in the German V2 (1942) and the development of floated gyros and accelerometers by a team working under Dr Draper at the Massachusetts Institute of Technology (1946).