Assessment of ship manoeuvrability by using a coupling between a nonlinear transient manoeuvring model and mathematical programming techmques

In this paper, a numerical method based on a coupling between a mathematical model of nonlinear transient ship manoeuvring motion in the horizontal plane and Mathematical Programming （MP） techniques is proposed. The aim of the proposed procedure is an efficient estimation of optimal ship hydrodynamic parameters in a dynamic model at the early design stage. The proposed procedure has been validated through turning circle and zigzag manoeuvres based on experimental data of sea trials of the 190 000- dwt oil tanker. Comparisons between experimental and computed data show a good agreement of overall tendency in manoeuvring traiectories.     

A simple smoother for attitude and position estimation using inertial sensor

This paper proposes a simple smoother algorithm for inertial sensor-based motion tracking. It is assumed that the motion consists of moving and non-moving intervals such as golf swing, which consists of not-moving (before swing), moving (swing), not-moving (after swing) intervals. A computationally efficient suboptimal smoothing algorithm is proposed. The proposed algorithm can be used in the application with limited computational power like in a smartphone application. Through a simulation and two experiments, the proposed algorithm is verified.

     

Automatically improving image quality using tensor voting

A novel corrupted region detection technique based on tensor voting is proposed to automatically improve the image quality. This method is suitable for restoring degraded images and enhancing binary images. First, the input images are converted into layered images in which each layer contains objects having similar characteristics. By encoding the pixels in the layered images with second-order tensors and performing voting among them, the corrupted regions are automatically detected using the resulting tensors. These corrupted regions are then restored to improve the image quality. The experimental results obtained from automatic image restoration and binary image enhancement applications show that our method can successfully detect and correct the corrupted regions.     

The BIOMASS mission: Mapping global forest biomass to better understand the terrestrial carbon cycle

In response to the urgent need for improved mapping of global biomass and the lack of any current space systems capable of addressing this need, the BIOMASS mission was proposed to the European Space Agency for the third cycle of Earth Explorer Core missions and was selected for Feasibility Study (Phase A) in March 2009. The objectives of the mission are 1) to quantify the magnitude and distribution of forest biomass globally to improve resource assessment, carbon accounting and carbon models, and 2) to monitor and quantify changes in terrestrial forest biomass globally, on an annual basis or better, leading to improved estimates of terrestrial carbon sources (primarily from deforestation); and terrestrial carbon sinks due to forest regrowth and afforestation. These science objectives require the mission to measure above-ground forest biomass from 70° N to 56° S at spatial scale of 100-200 m, with error not exceeding ± 20% or ± 10 t ha^− 1 and forest height with error of ± 4 m. To meet the measurement requirements, the mission will carry a P-Band polarimetric SAR (centre frequency 435 MHz with 6 MHz bandwidth) with interferometric capability, operating in a dawn-dusk orbit with a constant incidence angle (in the range of 25°-35°) and a 25-45 day repeat cycle. During its 5-year lifetime, the mission will be capable of providing both direct measurements of biomass derived from intensity data and measurements of forest height derived from polarimetric interferometry. The design of the BIOMASS mission spins together two main observational strands: (1) the long heritage of airborne observations in tropical, temperate and boreal forest that have demonstrated the capabilities of P-band SAR for measuring forest biomass; (2) new developments in recovery of forest structure including forest height from Pol-InSAR, and, crucially, the resistance of P-band to temporal decorrelation, which makes this frequency uniquely suitable for biomass measurements with a single repeat-pass satellite. These two complementary measurement approaches are combined in the single BIOMASS sensor, and have the satisfying property that increasing biomass reduces the sensitivity of the former approach while increasing the sensitivity of the latter. This paper surveys the body of evidence built up over the last decade, from a wide range of airborne experiments, which illustrates the ability of such a sensor to provide the required measurements.At present, the BIOMASS P-band radar appears to be the only sensor capable of providing the necessary global knowledge about the world's forest biomass and its changes. In addition, this first chance to explore the Earth's environment with a long wavelength satellite SAR is expected to make yield new information in a range of geoscience areas, including subsurface structure in arid lands and polar ice, and forest inundation dynamics.     

An empirical investigation into open source web applications’ implementation vulnerabilities

Current web applications have many inherent vulnerabilities; in fact, in 2008, over 63% of all documented vulnerabilities are for web applications. While many approaches have been proposed to address various web application vulnerability issues, there has not been a study to investigate whether these vulnerabilities share any common properties. In this paper, we use an approach similar to the Goal-Question-Metric approach to empirically investigate four questions regarding open source web applications vulnerabilities: What proportion of security vulnerabilities in web applications can be considered as implementation vulnerabilities? Are these vulnerabilities the result of interactions between web applications and external systems? What is the proportion of vulnerable lines of code within a web application? Are implementation vulnerabilities caused by implicit or explicit data flows? The results from the investigation show that implementation vulnerabilities dominate. They are caused through interactions between web applications and external systems. Furthermore, these vulnerabilities only contain explicit data flows, and are limited to relatively small sections of the source code.     

Gas Sensing with Perovskite-like Oxides Having ABO3 and BO3 Structures

WO₃ and LaFeO₃ are considered as example oxides in gas sensing, respectively of perovskitelike BO₃ and ABO₃ oxide groups, the structural chemistry of which is based on corner-sharing octahedral oxygen networks where transition metal cations B occupy the octahedral cages of oxygen anioins. WO₃ is an n-type semiconductor and many magnetic perovskites like LaFeO₃ are p-type semiconductors. There is a great flexibility inherent in the structure of both oxide groups which gives a lot of possibilities for structure engineering of the oxides for gas-sensing applications, e.g., by a temperature treatment or by modifying with impurity atoms. We have used here a high-temperature process, advanced reactive gas deposition, to produce nanoparticle thick films of WO₃ with the metastable tetragonal crystal structure at low temperatures up to 300–400C, and sol-gel citrate method to produce nanocrystalline LaFeO₃ powder as pure and modified with Sr and Mg, respectively.     

Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates

In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells.     

Query-driven indexing for scalable peer-to-peer text retrieval

In this paper, we present a query-driven indexing/retrieval strategy for efficient full text retrieval from large document collections distributed within a structured P2P network. Our indexing strategy is based on two important properties: (1) the generated distributed index stores posting lists for carefully chosen indexing term combinations that are frequently present in user queries, and (2) the posting lists containing too many document references are truncated to a bounded number of their top-ranked elements. These two properties guarantee acceptable latency and bandwidth requirements, essentially because the number of indexing term combinations remains scalable and the posting lists transmitted during retrieval never exceed a constant size. A novel index update mechanism efficiently handles adding of new documents to the document collection. Thus, the generated distributed index corresponds to a constantly evolving query-driven indexing structure that efficiently follows current information needs of the users and changes in the document collection.We show that the size of the index and the generated indexing/retrieval traffic remains manageable even for Web-size document collections at the price of a marginal loss in precision for rare queries. Our theoretical analysis and experimental results provide convincing evidence about the feasibility of the query-driven indexing strategy for large scale P2P text retrieval.