Applicability of time-of-flight-based ground and multispectral aerial imaging for grapevine canopy vigour monitoring under direct root-zone deficit irrigation

ABSTRACT

This study investigates the applicability of ground-based 3D time-of-flight (ToF) imaging and small unmanned aerial system (UAS) integrated multispectral imaging as a rapid grapevine canopy vigour mapping tool for decision support during crop production management. Direct root-zone deficit irrigation was applied to grapevines with continuous and pulse irrigation techniques at 15%, 30%, and 60% rates as that of standard irrigation rate (100%) established by the grower in a commercial production. The control block was irrigated continuously at 100% standard irrigation rate. Field plots were imaged using ground platform integrated with 3D ToF imaging sensor and small UAS-integrated multispectral camera at 128 and 65 days before the harvest to estimate the canopy vigour variability associated with irrigation treatments. Customized as well as standard methods (convex hull and voxel grid) were utilized to extract canopy attributes (e.g. volume) from the 3D ToF imaging sensor data. The multispectral images were processed to extract normalized and green normalized difference vegetation index images. Resulting data were used to estimate canopy area ratio i.e. the ratio between the grapevine canopy area with respect to the total area in selected region of interest. A significant correlation (r = 0.34) between canopy volume estimated by customized algorithm and aerial canopy area ratio was observed. Custom canopy volume estimates were also highly correlated (r = 0.79) with voxel grid derived canopy volume data. Overall, 60% continuous direct root zone deficit irrigation appeared to produce canopy volume/vigour comparable with those under control treatment. Results also suggest that grower can utilize either or both (ground and aerial) grapevine canopy mapping techniques for effective management.     

A study to support agile methods more effectively through traceability

Traceability is recognized to be important for supporting agile development processes. However, after analyzing many of the existing traceability approaches it can be concluded that they strongly depend on traditional development process characteristics. Within this paper it is justified that this is a drawback to support adequately agile processes. As it is discussed, some concepts do not have the same semantics for traditional and agile methodologies. This paper proposes three features that traceability models should support to be less dependent on a specific development process: (1) user-definable traceability links, (2) roles, and (3) linkage rules. To present how these features can be applied, an emerging traceability metamodel (TmM) will be used within this paper. TmM supports the definition of traceability methodologies adapted to the needs of each project. As it is shown, after introducing these three features into traceability models, two main advantages are obtained: 1) the support they can provide to agile process stakeholders is significantly more extensive, and 2) it will be possible to achieve a higher degree of automation. In this sense it will be feasible to have a methodical trace acquisition and maintenance process adapted to agile processes.     

Backstepping - Sliding Mode Controllers Applied to a Fixed-Wing UAV

This paper deals with the design of five controllers, based on Backstepping and Sliding Modes, which are applied to a fixed-wing unmanned aerial vehicle (UAV). We are interested to realize a comparative analysis of such methodologies in order to know what controller has a better performance when they are used to the autonomous flight (altitude, yaw and roll) of a fixed-wing UAV. The designed controllers are: Backstepping, Sliding Mode control (SMC), Backstepping with Sliding Mode control, Backstepping with two Sliding Mode control, and Backstepping with high order Sliding Mode (HOSM) control. Simulation results are obtained in order to analyze the controllers performance. We finally present an experimental result, in open-loop, with the purpose of validate the magnitude of the control signals obtained in the simulations.     

Selective Harmonic Elimination in Multimodule Three-Phase Current-Source Converters

Modular current-source converter (MCSC) structures can enhance the current capacity and improve the power quality of converters in medium-voltage pulsewidth-modulated applications. An MCSC uses individual three-phase modules in a shunt connection to share the total power in a symmetrical manner. The modulation of these units is normally done using optimized patterns such as selective harmonic elimination patterns. However, the optimization is usually performed at the module level. This paper proposes a modulation technique that optimizes the operation of a complete MCSC taking into account all $P$ modules. Thus, from the injected ac current, we remove $P$ times the number of harmonics as compared with the conventional approach using the same switching frequency. A complete mathematical formulation and experimental results validate the proposed approach.      

Nevus of Ota acquisita of late onset

Nevus of Ota is a melanotic pigmentary disorder characterized by its distinctive cutaneous distribution involving skin innervated by the trigeminal nerve. Most cases are clinically manifest at birth or around puberty; however, acquired lesions in adults have been reported. We report a case of nevus of Ota acquisita that occurred in an eighty-one-year-old man.     

Treatment of antral and duodenal bleeding ulcers by Guevara's catheter

The catheter is based on the principle of compression and tamponage, assuring and guaranteeing hemostasis at the base of the ulcer. This method is suitable for permanently controlling an acute hemorrhage in the event medical treatment fails and surgery is contraindicated. Emergency surgery is changed to elective surgery with all its advantages.     

Grinding operation optimization of the CODELCO-Andina concentrator plant

This paper presents results following the application of a sub-optimal control scheme, both through simulation and in situ, from the operation of Section C of the CODELCO-Andina copper concentrator plant. The algorithm permits the determination of the necessary control action at each instant of time in order to maximize a defined plant performance index. The main objective of the algorithm is to maximize the mineral tonnage processed by the section, subject to it not exceeding a predetermined value establishes! for the operation conditions of the mills, while at the same time maintaining constant the mass fraction over 65 mesh (212 [microns]) in the overflow of the hydrocyclones, at a value within the operational requirements of the flotation stage. The performance index is defined in terms of; the percentage of pulp solids fed to the hydrocyclones of each line of ball mills, penalty functions to prevent electric power to the ball mills ,falling below the lower limit (so as not to enter the overload region), the tonnage processed in the section, and, since water is a scarce resource, a term considering the water added to each sump is also included. The scheme is first studied and adjusted in a simulator of a concentrator plant similar to that used in the industrial application. For plant implementation, a PC software program, denoted CONMOL, is developed in TurboPascal for Windows. This software allows plant applications to be carried out through a communications interface. Finally, the results of two tests performed on Section C of the CODELCO-Andina copper concentrator plant are shown where the control is applied over 3 and 5.5 hours respectively.     

Residual shunts after application of the Rushkind occlusion system in closure of persistent ductus arteriosus. Insertion of a second device

From May 1991 to August 1994, we performed transcatheter closure of patent ductus arteriosus with Rashkind umbrella system in 25 patients. In one, the device had embolism, to the right pulmonary artery and was operated 24 hs afterwards without complications. Seven had residual shunts, two had subsequent surgery, two are being followed (one for mild and one for moderate residual shunt). In the other three cases we inserted a second device. We used a 12 mm device in two cases and a 17 mm device in the other. Two cases had total occlusion 24 hrs after and in one had mild residual shunt without clinical repercussion. There were no complications. All had electrocardiographic and clinical improvement, take no medication, and their cardiomegaly had decreased (Cardiac index pre 61 vs post 54%). In conclusion the insertion of a second device is safe and effective alternative for residual shunt after first Rashkind occluder.