COSMO-SkyMed high resolution fully polarimetric synthetic aperture radar exploitation - the ‘strip-spot’ approach

This focused study aimed to generate a fully polarimetric synthetic aperture radar (SAR) data set of 1 m resolution based on the spotlight and stripmap COSMO-SkyMed (CSK) satellite data fusion. The results show the feasibility of overcoming the limitation of the nominal 3 m resolution generated by a series of multi-temporal stripmap SAR data observed in all the polarisations. The CSK satellite system does not allow the observation of cross-polar data in the spotlight acquisition mode because only co-polar data are available. In this work, a fully polarimetric scattering matrix is estimated by using two spotlights in the horizontal horizontal (HH) and vertical vertical (VV) polarisations and two stripmaps in the horizontal vertical (HV) and vertical horizontal (VH) polarisations. The stripmaps were resampled and super-resolved by using the amplitude and phase estimation of sinusoids (APES) filter to achieve the spotlight resolution. The results show that the proposed strip-spot approach has immediate operative applications.     

Applications of Radarsat‐1 synthetic aperture radar imagery to assess hurricane‐related flooding of coastal Louisiana

The Louisiana coast is subjected to hurricane impacts including flooding of human settlements, river channels and coastal marshes, and salt water intrusion. Information on the extent of flooding is often required quickly for emergency relief, repairs of infrastructure, and production of flood risk maps. This study investigates the feasibility of using Radarsat‐1 SAR imagery to detect flooded areas in coastal Louisiana after Hurricane Lili, October 2002. Arithmetic differencing and multi‐temporal enhancement techniques were employed to detect flooding and to investigate relationships between backscatter and water level changes. Strong positive correlations (R ² = 0.7–0.94) were observed between water level and SAR backscatter within marsh areas proximate to Atchafalaya Bay. Although variations in elevation and vegetation type did influence and complicate the radar signature at individual sites, multi‐date differences in backscatter largely reflected the patterns of flooding within large marsh areas. Preliminary analyses show that SAR imagery was not useful in mapping urban flooding in New Orleans after Hurricane Katrina's landfall on 29 August 2005.     

Ground truth requirements for radar observations over land and seat†

Abstract

At a first stage of development, ground truth is gathered in conjunction with radar data in order to establish statistical correlations between observed backscatter and properties of the irradiated surface. Significant correlations have been shown to exist between backscatter and many geophysical quantities; for example scatterometer measurements over the ocean can be used to infer wind speed, synthetic aperture radar (SAR) measurements over woodland can allow the separation of tree species, etc. Once statistical relationships are established, the next stage is to try to understand the physics underlying the relationship, both because of its intrinsic interest and because of the need to optimize system performance for particular applications. This places a second role on ground truth, since it must be used to validate the physical theories stemming from it. Microwave scattering from land surfaces is a topic of growing interest as we look towards land observation missions within the coming decade. Several theories have been proposed to account for scattering from surfaces of a vegetation layer, but none of these has been rigorously tested. If they are to contribute effectively to future land missions, it is essential that such testing be carried out. The first section of this paper describes the requirements such testing will put on ground measurements, and tries to identify whether such measurements are feasible. Microwave scattering mechanisms from the sea surface, and particularly their effects on SAR images of waves, and clutter-statistics in SAR sea-surface images are still a matter of some debate. The second section of this paper outlines the problems inherent in sea imaging with SAR and describes experiments that need to be carried out in order that these questions can be resolved.     

Do organisational and environmental factors moderate the effects of Internet-based interorganisational systems on firm performance?

We developed a model of the relationships among several organisational, interorganisational and technological factors, the adoption of Internet-based interorganisational systems (IBIS) and various measures of firm performance. We used structural equation modelling to empirically test these relationships. The findings showed that adopting IBIS indirectly improves the operational performance of firms through business process performance. The positive effect on financial performance of adopting IBIS is not direct, but through the mediating effects of operational performance and business process performance. We also utilised multiple group analysis to test some of the model relationships across firms using several organisational and environmental factors as moderators. The organisational factors tested are firm type, age and ownership type. The environmental factors consisted of dynamism, complexity and hostility. We found that the organisational factors are significant moderators and that complexity and hostility are not significant moderators. However, the effects of dynamism as a moderator are less clear.     

Squeeze film effects on dynamic performance of MEMS μ-mirrors-consideration of gas rarefaction and surface roughness

The squeeze film behavior of MEMS torsion mirrors is modeled, analyzed and discussed. Effects of gas rarefaction (first-order slip-flow model with non-symmetric accommodation coefficients, ACs) and surface roughness are considered simultaneously by using the average Reynolds type equation (ARTE). Based on the operating conditions with small variations in film thickness and pressure, the ARTE is linearized. A coordinate transformation, by stretching or contracting the axes by referring to the roughness flow factors, is proposed to transform the linearized ARTE into a diffusion type modal equation. The dynamic coefficients (stiffness and damping coefficients) are then derived and expressed in analytical form. The results show that the tilting frequency (or Γ₀ squeeze number), roughness parameters (γ Peklenik numbers, σ standard deviation of composite roughness) and gas rarefaction parameters (D inverse Knudsen number, ACs) are all important parameters on analyzing the dynamic performance of MEMS torsion mirrors.     

The effects of 3D interface metaphor on older adults’ mobile navigation performance and subjective evaluation

Navigating vast information spaces through mobile interfaces has become a common activity in older adults' everyday lives. Studies suggested that interface metaphors could be used to facilitate users' metal model development and information processing when using mobile technologies. However, we know little about how metaphors affect older adults' mobile navigation behavior, and which user characteristics matter during this perceptual and cognitive process. To investigate this, a card interface with a 3D metaphor and a list interface without 3D metaphors were compared among twenty-two participants when performing four navigation tasks. User characteristics including demographic factors, technology experience, and user capabilities were examined. The participants' navigation performance and subjective evaluations were measured as the dependent variables. From the results, we recommend the list interface without 3D metaphors as a beneficial choice for older adults. It performed better in navigation performance, although the differences are not statistically significant. Moreover, navigation performance using the card interface with a 3D metaphor was significantly associated with participants' perceptual speed, thus this interface may be more sensitive to capability declines. Valuable insights into the older adults’ mobile navigation performance and preferences are discussed and important implications for the design of mobile navigation user interfaces are proposed based on the results.Relevance to industryThe experimental results propose a more beneficial way to present contents on a mobile user interface for older adults and provide valuable insights for the designers and industry to help them understand the older adults’ usage and perceptions towards the application of 3D metaphors when navigating with mobile interfaces.     

The effect of Facebook use on office workers’ job performance and the moderating effects of task equivocality and interdependence

As office workers’ use of social networking sites (SNSs) has increased, so has research interest in the effect of SNS use on job performance. The present study employs data collected from South Korean office workers to examine how the use of the SNS Facebook affects job performance and to investigate the moderating effects of task characteristics (task equivocality and task interdependence). The results show that Facebook use for work has a positive effect on job performance, although the time spent on Facebook use does not have a significant effect on job performance. Moreover, task interdependence is associated with a decrease in the effect of Facebook use for work on job performance. In other words, task interdependence has a negative moderating effect on the impact of Facebook use for work on job performance. The reason is that Facebook is particularly advantageous for enhancing performance in tasks where the level of interdependence is low because it is a medium with relatively low synchrony and is unsuitable for one-to-one relationship building. This study has implications for companies that are concerned about formulating policies related to employees’ use of SNSs.     

Analysis of submarine steering: effects of cognitive and perceptual–motor requirements on the mental workload and performance of helmsmen

The purpose of the study is to model manual submarine steering and its effects on helmsmen in terms of performance and mental workload. This activity is first formalized according to (a) cognitive requirements, by identifying different levels of control, and (b) perceptual–motor requirements, by analysing the directional compatibility of control–display design. An experiment is then carried out on a simulator designed by a world leader in military naval shipbuilding. This experiment follows a unique scenario including two driving situations with different levels of cognitive requirements (approach and stabilization phases). It is achieved by two groups, each carrying out a perceptual–motor task on a specific steering control–display configuration proposed by the naval shipbuilder (one with a standard numeric display and one with a new visual–spatial representation, both tasks controlled by the same joystick). The findings of this study show that the cognitive requirements during the stabilization phase with high propulsion speed produce increased mental workload, and the perceptual–motor requirements also produce increased mental workload when a direction-of-motion stereotype is violated (upward–forward relationship).     

Design and performance analysis of RAID based on OSD

Today＇s SAN architectures promise unmediated host access to storage. To keep this promise, however, several issues and opportunities raised by SANs must be addressed, including security, scalability and management. Object storage, such as introduced by the NASD work, is a means of addressing these issues and opportunities. RAID using Object-Based Storage Devices is described, about which some issues are discussed and then its performance by queuing model is investigated.     

Some Studies on Two and Three-level Simplified Expressions of Boolean Functions†

A method of directly testing whether the AND-OR or the OR-AND form of a switching function is more economic for some simple cases is presented. Simplified expressions leading to economic three-level synthesis have also been derived.     

Digital at the edge – antecedents and performance effects of boundary resource deployment

With business ecosystems digitalizing by the force of digital innovation, the deployment of boundary resources (such as application programming interfaces: APIs) becomes a strategic option across contexts. We distinguish between boundary resources that provide access openness and those that provide resource openness, and theorize the antecedents and consequences of their deployment. Employing panel data regressions to a longitudinal cross-industry dataset, we find that the digital knowledge base of the focal firm and the existence of potential digital complementors drive boundary resource deployment. Such deployment benefits firm performance depending on the firm’s market power. From our empirical analysis, we reveal a differentiated perspective on the quality of the confined openness provided by boundary resources as well as the embeddedness of their deployment in the rationales and motivations of the associated actors in digital business ecosystems. We complement the existent theoretical framework on boundary resources and provide valuable insights to managers reflecting about deploying boundary resources in a beneficial way.     

The effects of relationship benefit on relationship quality and store loyalty from convergence environments—NPS analysis and moderating effects

The primary concern of CRM is core customers from convergence environments. They show such passionate partnership with the company that they actively put forth their opinion to improve products and service through voluntary pro-company activities and participate in the development of new products through open innovation. Therefore, the top priority of a company should be given to defining its core customers and accurately understanding and managing them, which would contribute to the growth of the company. This study has the purpose to identify net promoter score (NPS) of company by adopting index that evaluates the degree of customer loyalty to the company in judging the relationship of company and customer, and later on establish strategy to increase the number of loyal customers by classifying customers by the score. It has become more important nowadays how to manage a long-term customer relationship, for it can assure the company of increased income in spite of steep competition with rival companies. Therefore strong customer relationship is an important means of proving the company with competitive edge and maximizing company income. In addition, as NPS serves as adjustment variable, net promoters were analyzed to contribute to store loyalty significantly. The way for bookstore ‘A’ to grow as a company with potential for future growth would be re-establish customers through one more in-depth analysis of customers as well as seek for methods to raise NPS.     

The relation between reflected radiation and yield on the Broadbalk winter wheat experiment†

Abstract

In the classical experiment on Broadbalk field, Rothamsted, winter wheat has been grown continuously under various treatments since 1843. Reflected radiation in red (R) and near-infrared (NIR) wavebands was measured over the field in 1987, twice with an airborne multispectral scanner (MSS) from an altitude of 600m and five times with a muhiband radiometer from 2 m above the crop surface. The normalized difference vegetation index, NDVI= ( NIR?R)/ (NIR + R), was calculated for each date and its relation with harvest yield investigated.

The NDVI determined from the airborne MSS data was correlated with yield, and the correlation was found to increase if the variable effect of productivity was introduced into the relationship. The NDVI values calculated from the ground radiometry were more strongly correlated with yield, however. The differences in yield on Broadbalk are caused mainly by the amounts of nitrogen-containing fertilizer applied. The results suggest that the radiation measured by airborne MSS can give a rough guide to yield and nitrogen nutrition, whereas ground radiometry could be used to predict yield and potential deficiencies of nitrogen.     

Functional relationships between the conventional steady-state error characteristics and the weighting matrices in the quadratic performance index†

The requirements for achieving a desired value of steady-state error for an optimal control system utilizing the quadratic performance index with a linear plant arc derived for step, ramp and parabolic inputs. These requirements result in a number of the elements of the Riccati matrix being specified in terms of known parameters. It is shown that for an all-pole plant the control system cannot follow a parabolic input. For the stop input the q ₁₁ element of the Q matrix is specified as one for an all-pole plant or in terms of the fixed plant parameters for a pole-zero plant. Depending on the number of requirements and the order of the system it may be necessary to assume values for the remaining elements of the Q matrix in order to solve the reduced Riccati equation.     

I spy with my AI: The effects of AI-based visual cueing on human operators’ performance and cognitive load in CCTV control rooms

The increased number of security cameras in modern cities has elevated the video-feed monitoring demands of closed-circuit television (CCTV) operators. As a result, new AI-driven support systems that leverage the power of computer vision algorithms have been deployed to facilitate the operators' work. However, to effectively design intuitive, AI-driven interfaces and validate their impact on the operators' performance, extensive user testing is required. To address this, we previously developed and tested a virtual reality (VR) control room that can be used to iteratively evaluate intelligent computer assistants and interfaces while operators are subjected to different cognitive load. In the present study, we use this VR environment and physiological markers (e.g., eye tracking measures) to investigate how AI-based visual cueing (i.e., pushing forward video streams on which detections are highlighted by rectangles drawn around targets) affects operator performance and cognitive load. Results suggest that support systems using such technology in a control room improve operators’ performance and decrease their cognitive load, as reflected by changes in pupil dilation and subjective reports irrespective of induced cognitive load.     

Automating and informating: roles to examine technology’s impact on performance

Previous studies on the impact of technology on performance (usefulness) have looked at the Information System (IS) in its role as supplier of information (informating role) and thus they have studied the influence of information quality and system quality on usefulness. However, an IS also has a role in the automation of tasks (automating role), which these studies do not take into account. Accordingly, this paper proposes a factor model that (1) includes explicitly both roles; (2) considers that informating and automating roles mediate the relation between these technological factors (information quality and system quality) and usefulness and (3) includes a system’s level of intervention (i.e. the degree to which technology participates in carrying out the tasks) as an additional factor that determines usefulness. Using a questionnaire, data were gathered on 229 Enterprise Resource Planning system users from different organisations and functional areas and structural equations model was used for analysis. Results show that information quality explains usefulness through both roles. System’s level of intervention explains usefulness through the automating role and system quality explains usefulness through the informating role. The factors’ differentiated effects through each role may help managers to establish more effective criteria and priorities in the various stages of an IS’s life cycle.     

Effects of perceptual complexity on older and younger adults’ target acquisition performance

The present study evaluated the effects of the three perceptual complexity factors: number of elements, colour variety, and graphical background clutter level, on older and younger adults’ target acquisition time within a computer display. Experiment 1 manipulated the total number of icons, Experiment 2 manipulated the variety of icon colours, and Experiment 3 manipulated the clutter level of the graphical background on the display. In each experiment, 12 older and 12 younger adults were asked to move a cursor to a target icon on the display as quickly and accurately as possible. Target size and distance to the cursor were also manipulated to yield different difficulties of targets. Target acquisition time and Fitts’ law slope were analysed. Results showed that target acquisition time increased for more difficult targets under all the three complexity factors. The amount of increase was more evident for the factors of colour variety and graphical background clutter than for the number of icons. Older participants performed more slowly than younger participants did, particularly for more difficult targets. However, the impact of the three complexity factors on acquisition time appeared to be comparable for both age groups. The results suggest that implementations of colour varieties and graphical backgrounds on interfaces should be restricted, especially when icon acquisition is a common activity involved in interacting with an interface.     

Impact of hand-assisted viewing on user performance and?learning patterns in virtual environments

The ability to locate, select and interact with objects is fundamental to most Virtual Reality (VR) applications. Recently, it was demonstrated that the virtual hand metaphor, a technique commonly used for these tasks, can also be employed to control the virtual camera, resulting in improved performance and user evaluation in visual search tasks.     

Novel Adaptive Balloon Active Contour Method based on internal force for image segmentation – A systematic evaluation on synthetic and real images

Many studies have been conducted on digital image segmentation, seeking to overcome the limitations of different methods for specific applications. Thus, existing techniques are improved and new methods created. This paper proposes a new Active Contour Method (ACM) applied to the segmentation of objects in digital images. The proposed method is called Adaptive Balloon ACM and its main contribution is the new internal Adaptive Balloon energy that minimizes the energy of each point on the curve using the topology of its neighboring points, and thus moves the curve toward the object of interest. The method can be initialized inside or outside the object of interest, and can even segment objects that have complex shapes. There are no limitations as to its startup location. This work evaluates the proposed method in several applications and compares it with other ACMs in the literature. This new method obtained superior results, especially when the objects to be segmented were tubular and had bifurcations. Thus the proposed method can be considered effective in segmenting complex shapes in digital images and gave promising results in various applications.