DP Systems Research Articles

Comparative physiological, metabolomic and transcriptomic analyses reveal the mechanisms of differences in pear fruit quality between distinct training systems

BackgroundCanopy architecture is critical in determining the fruit-zone microclimate and, ultimately, in determining an orchard’s success in terms of the quality and quantity of the fruit produced. However, few studies have addressed how the canopy environment leads to metabolomic and transcriptomic alterations in fruits. Designing strategies for improving the quality of pear nutritional components relies on uncovering the related regulatory mechanisms.ResultsWe performed an in-depth investigation of the impact of canopy architecture from physiological, metabolomic and transcriptomic perspectives by comparing pear fruits grown in a traditional freestanding system (SP) or a flat-type trellis system (DP). Physiological studies revealed relatively greater fruit sizes, soluble solid contents and titratable acidities in pear fruits from DP systems with open canopies. Nontargeted metabolite profiling was used to characterize fruits at the initial ripening stage. Significant differences in fruit metabolites, including carbohydrates, nucleic acids, alkaloids, glycerophospholipids, sterol lipids, and prenol lipids, were observed between the two groups. Transcriptomic analysis indicated that a series of organic substance catabolic processes (e.g., the glycerol-3-phosphate catabolic process, pectin catabolic process and glucan catabolic process) were overrepresented in fruits of the DP system. Moreover, integrative analysis of the metabolome and transcriptome at the pathway level showed that DP pear fruits may respond to the canopy microenvironment by upregulating phenylpropanoid biosynthesis pathway genes such as PpPOD. Transient assays revealed that the contents of malic acid and citric acid were lower in the pear flesh of PpPOD RNAi plants, which was associated with regulating the expression of organic acid metabolism-related genes.ConclusionsOur results provide fundamental evidence that at the physiological and molecular levels, open-canopy architecture contributes to improving pear fruit quality and is correlated with increased levels of carbohydrates and lipid-like molecules. This study may lead to the development of rational culture practices for enhancing the nutritional traits of pear fruits.

Evaluation of the Qualification of Dynamic Positioning Operators Using Analytic Hierarchy Process

Offshore vessel operations are always important for the industry as the consequences of incidents related to dynamic positioning systems may affect people, cargo, vessels, and the environment. The aim of this paper is to determine the qualification factors and improve the competency standards of Dynamic Positioning Operators (DPOs). The Analytic Hierarchy Process method has been used for this study by processing expert views of senior operators who have at least fifteen years of dynamic positioning experience. The results show that quality of trainer, importance of sea time collected after achieving a full DPO certificate, experience with different types of DP systems, and practical knowledge are defined as the most important factors to becoming a qualified dynamic positioning operator. Besides, situational awareness of DP operators is considered another important factor to reduce possible dynamic positioning incidents. In conclusion, this study provides the following recommendations: promote incentive programmes in order to appeal to potential trainers, increase the length of minimum required sea time after a simulator course, increase the required practical time onboard in lieu of transferring excessive active sea time to further stages, companies to provide familiarisation courses for operators regarding the equipment onboard prior to joining the vessel for the first time, and promote online training programmes to improve the situational awareness of operators. By using these recommendations, there is a possibility to improve the qualification of DP operators and reduce incidents related to dynamic positioning operations. Last but not least, this research can also be used as a reference in the offshore industry for the training of Dynamic Positioning Operators (DPOs).

Features of Dynamism Wharf-Cable-Dynamic-Positioning Vessel Rigid-Flexible Coupling Multi-Body System Analysis

The conventional mooring positioning technique is cost-effective; however, it shows poor maneuverability and positioning precision. In this study, to calculate the mooring tension, mooring cables were discretized into lumped mass models using the lumped mass technique. Dock fender nonlinear response forces were modeled in OrcaFlex using the Link unit. The multi-body system’s entire coupling vibrant time-frequency features have been examined. The effect of the side thrusters on removing the vessel motion carried on by the first-order wave loads has been determined under mooring conditions by comparing the difference in horizontal degree of freedom motion and the mooring line’s mooring tension between dynamic and non-dynamic positioning vessels (DPV). The impact of the wharf-cable and target position on side thrusters and positioning capabilities are analyzed, considering the results of both vessels under identical environmental loads. The results demonstrate that deep evaluation of the target position can greatly improve side thruster performance and ship positioning precision. DP systems are weak to cancel linear wave forces, and the missing ship motions for DP ships may be due to the combined action of the fender, moorings and the selection of a good target position. When the selection of the target position is unreasonable, the size of the pre-tension of the mooring line cannot meet the requirement of absorbing the first-order wave load on the vessel.

Canine Mammary Tumor Histopathological Image Classification via Computer-Aided Pathology: An Available Dataset for Imaging Analysis.

Histopathology, the gold-standard technique in classifying canine mammary tumors (CMTs), is a time-consuming process, affected by high inter-observer variability. Digital (DP) and Computer-aided pathology (CAD) are emergent fields that will improve overall classification accuracy. In this study, the ability of the CAD systems to distinguish benign from malignant CMTs has been explored on a dataset-namely CMTD-of 1056 hematoxylin and eosin JPEG images from 20 benign and 24 malignant CMTs, with three different CAD systems based on the combination of a convolutional neural network (VGG16, Inception v3, EfficientNet), which acts as a feature extractor, and a classifier (support vector machines (SVM) or stochastic gradient boosting (SGB)), placed on top of the neural net. Based on a human breast cancer dataset (i.e., BreakHis) (accuracy from 0.86 to 0.91), our models were applied to the CMT dataset, showing accuracy from 0.63 to 0.85 across all architectures. The EfficientNet framework coupled with SVM resulted in the best performances with an accuracy from 0.82 to 0.85. The encouraging results obtained by the use of DP and CAD systems in CMTs provide an interesting perspective on the integration of artificial intelligence and machine learning technologies in cancer-related research.

Application of fuzzy spiking neural dP systems in energy coordinated control of multi-microgrid

Application of fuzzy spiking neural dP systems in energy coordinated control of multi-microgrid

Repercussion of pastoral systems in C and N fractions stock in northeast Amazonia

Changes with land use and management are the second largest cause of greenhouse gas emissions (E-GHG) into the atmosphere. So, it is important to better understand agricultural systems regarding C and N stocks, which are directly associated with soil quality. The objective of this work was to evaluate the impacts of pastoral use systems on C and N stocks and the natural abundance of 13C (δ13C) in the fractions of soil organic matter in the Brazilian Amazon biome. The pastoral systems evaluated involved two silvopastoral systems with 30% (SP30) and 60% (SP60) of shading, two full-sun pasture systems, one in use and under intensive management (IMP) and other in fallow and is considered degraded (DP), as well as a control area under forest (NV). Dominant the grass of the pasture areas was Mombasa grass (Megathyrsus maximus). The experiment design consisted of four replicates where thecollection sites (trenches) were systematically distributed within the areas (SP30, SP60, NV, DP and IMP)and the layers (0–5, 5–15, 15–30, 30–60 and 60–100 cm). Silvopastoral system with 60% shading had the greatest carbon stock, even greater than the control forest at some depths. In comparison to the control condition (NV) in soil profile, SP30, DP and IMP, reduced C-total stocks by 24%, 17% and 20%, and N-total by 14%, 10% and 18%, respectively. The δ13C values were higher in the IMP and DP systems and lower in SP60 and NV, both in organic matter associated with minerals (MaOM) and particulate organic matter (POM). An isotopic enrichment occurred in all systems in the soil profile.

Control of Dynamic Positioning Ship Using Internal Model Control

Dynamic Positioning Ship System (DP) is an automated system, which is used to keep the ship maintain its position and heading at a fixed location or navigate along a predetermined track exclusively by mean of its own actives propulsions systems without using such fixing device as the anchor. DP system’s task is to control the ship moving at a fixed position or moves following the route for previous with low speed to execute a task. This paper presents a novel stability robustness controller for a dynamic positioning ship with uncertainties and unknown external disturbances. For the development and testing of the controller we present shematic diagram of DP systems, the mathematical modeling of the ship and the bias forces as slowly-varying environmental disturbances. The proposed controller has two loops. The inner loop uses an internal model control (IMC) technique to control the speed of the ship. The outer loop uses a propotional (P) control ler to control the position of the ship. The stability robustness of the control system is analysed. One of the key aspects of the prposed controller is that the robustness of the closed loop system can tuned via a single tuning parameter. The simulation results demonstrate that the proposed control system has high performance and robustness in the present of environment disturbance and uncertainty. The proposed control system was compared with PID control.The control algorithm of ship dynamic positioning is generally based on the classic PID, PID control has many advantages and has a strong robustness. However, the parameters of the PID control depend on the test will cost a lot of time and energy. Simulation results are provided to illustrate the effectiveness of the proposed controller. The problem of guidance and control of thruster actuators is out of scope of the paper.

Thrust Control Systems of Propulsion and their Verification on Dynamically Positioned Vessels

Abstract Thrust vector control systems of propulsion systems of dynamic positioning vessels are commonly applied on vessels with DP2 and DP3 class of DP. It was submitted the ways of providing information to dynamic positioning operator DPO about detecting of suspicion of failure in specific thruster and shown the ways of response in such situations. In the case of failure and shut down one of working thrusters, it must be done the possibility assessment of continuation of DP system safe operation. If such situation is not possible, it should be considered the work of DP system on limitations. It was indicated on safety threats during operation of DP systems resulting from system failure or even the design faults. It commonly applies the failure mode and effect analysis (FMEA or FMECA) from the design phase through sea trials until to the verification process during operation. It allows the elimination of majority of faults in the DP systems. It was communicated the basic conditions of safe operation of vessels with DP systems and the examples of conditions which releasing the readiness signal of DP propulsion system elements. Observed development of control and automatics systems will result in increasing the safety of DP systems operation.

High Order Sliding Mode Control and Observation for DP Systems

Sliding Mode Controllers (SMC) are a robust and simple strategy suitable to mechanical systems subject to structured disturbances. Such characteristics make them an interest solution as control algorithms for Dynamic Positioning Systems, providing enhanced trajectory tracking capacities even during transients. The trade-off is usually a limit in accuracy, due to smoothing methods required to reduce control chattering. This work proposes the usage of a Second Order SMC method, named Super-Twisting control as an alternative for the application of SMC in DP Systems. This algorithm provides high accuracy and robustness while eliminating chattering. The solution is completed with the introduction of a High Order Sliding Mode Observer, which performs wave-filtering, velocity and drift estimation. The controller-observer structure is tested in a high fidelity marine simulation environment, producing results that confirm the performance of the system.

Solving the N-Queens problem using dP systems with active membranes

The N-Queens problem consists of placing N queens on an N×N chessboard such that no two queens threaten each other (i.e. same row, column, or diagonal). P systems solutions to the N-Queens problem and related problems (e.g. SAT) are often in a nondistributed way, i.e. the complete input to the problem enters the system through a single input membrane and the problem is solved. dP systems involve using more than one P system to solve problems in a distributed way, i.e. the problem input is partitioned and each partition enters the system using distinct components (which are also P systems). In this work, we solve the N-Queens problem using dP systems where the components are P systems with active membranes. Our 2-component and 3-component solutions partition the elements of the input multiset based on the clauses they represent. Compared to the nondistributed solution, our 2-component and 3-component solutions reduce the computation time by a half and by a third, respectively. Besides the analysis of the computation time, we also analyze communication costs. ComN, indicating the number of computation steps where communication occurred, is constant for both solutions. ComR, the number of intercomponent communication rules used, and ComW, the number of object communicated, are in terms of S, where S is the number of solutions to the problem instance.

Grasa y ácidos grasos en leche de vacas pastoreando, en cuatro sistemas de producción.

El objetivo de este trabajo fue evaluar el efecto de la dieta, número de partos y tercio de lactancia sobre el porcentaje de grasa, la concentración de ácido linoleico conjugado (ALC-c9t11), transvaccénico (ATV-C18:1t11) y otros ácidos grasos (AG) insaturados en la leche de vacas pastoreando en cuatro sistemas de producción. El trabajo se realizó de mayo a diciembre del 2012 en diez ganaderías colombianas, representativas de los sistemas de producción lechería tropical (LT) y doble propósito (DP) con/sin sistema silvopastoril intensivo de leucaena (SSPi). En cada ganadería se tomaron tres muestras individuales de leche, de cinco vacas (día 62 ± 22, día 147 ± 22 y día 227 ± 22 de lactancia), conjuntamente se estimó el consumo de suplemento y de forraje, y se determinaron AG en estos. Cada sistema de producción se analizó independientemente. El contenido de grasa en leche fue afectado por el tercio de lactancia (p<0,05) en LTSSPi y DPSSPi, presentando el primer tercio el menor valor. ALC-c9t11 en la leche varió entre 1,02 a 2,22%, ATV entre 4,40 a 6,50% y el índice de aterogenicidad entre 1,69 a 2,89. La alta participación de la grasa de los suplementos (51 a 84%) en el total de grasa consumida y su composición, llevó a variaciones en el per l de AG de la leche en los sistemas LT, LTSSPi y DP. El número de parto y el tercio de lactancia presentaron menor efecto que la dieta.

Advantages and disadvantages of thruster allocation procedures in preliminary dynamic positioning predictions

Minimisation of power consumption is the primary target of the most commonly used procedures and strategies for the capability prediction of DP systems installed on floating objects and, therefore, dealing with an huge amount of limitations or restrictions that should be satisfied at the same time for different operating conditions. However, in the particular case of the “extreme limit prediction” for a considered system, other factors assume a prominent importance instead of fuel consumption, like the ability to use all the available power to keep the position in heavy weather conditions.When the maximum operating cases for a vessel are analysed, other effects like thruster–hull interaction and thruster–thruster interaction are rarely considered.To take into account the above-mentioned effects, different thrust allocation strategies were studied and implemented in a capability prediction suite. In this paper a new allocation philosophy is presented, with the aim of maximising the DP capability of a vessel operating in heavy whether conditions. An application of the procedure on two existing offshore vessels is also considered to highlight the effects of different allocation strategies and of the interaction effects on the resulting DP capability in terms of “operational rosettes”.

Integrated Simulations of a Floating Crane Installation Vessel with DP systems in Waves

The nonlinear time-domain analysis method was implemented to carry out a series of integrated simulations for a deep-water crane vessel system composed of four sub components, including a floating vessel, lifted equipment, hoisting cable and dynamic positioning (hereinafter DP) system. The analysis of the coupled dynamics consists of the crane vessel and equipment connected using the crane wire, and the DP is modeled according to the wind, wave and current conditions. The DP systems were numerically implemented using a classical PD feedback controller, and various simulations of the deepwater installation were conducted using different conditions in order to evaluate the global performance of the floating crane vessel combined with the DP system.

Managing DP System Software - A Life-cycle Perspective

In a few decades, DP operations have gone from early prototyping to become a commodity and necessity to conduct most offshore operations. Today's DP vessels encompass offshore supply vessels, anchor-handlers, construction and diving vessels, shuttle tankers, semi-submersibles and drillships, as well as numerous other vessel types. Although the vessel types range widely in type and purpose, the DP systems are similar in structure and usually considered to be comprised of a number of different position reference and sensor systems, a DP computer system, a power system including generation, distribution and power management, and a propulsion system including thrusters, main propulsion and possibly rudders. At the heart of all these subsystems lies computer control systems, and at the heart of all computer control systems lies software.Experience from other industries shows that software is elusive and difficult to manage properly. None the less so for a DP vessel, where software from many different vendors come together to work as one integrated DP system. As technology has evolved and matured, the level of automation and integration has increased, and the complexity of the DP system has increased correspondingly. The software systems on a modern vessel by far exceeds any mechanical, electrical or hydraulic system in complexity and – more importantly – in lack of transparency. Do we have the right tools available to manage the risks associated with software on DP vessels today, both in the building phase and in the life-cycle of the vessel? And if so, are they understood and used correctly?This paper aims to highlight how independent Hardware-In-the-Loop (HIL) testing can be used to test, verify and validate the individual software components of the DP system, as well as the complete integrated system. The paper continues to show how HIL testing could be incorporated in the life-cycle of the vessel to manage and mitigate control system risk, both for newbuilds and sailing vessels.

CHALLENGES OF SHIP PROPULSION SYSTEMS DURING DP OPERATIONS

Ship propulsion configurations with dynamic positioning systems are commonly used as diesel-electric. In particular, situations for ship transfer on longer distances may be used conventional mechanical propulsion system with controllable pitch propeller. Combination of mechanical and electric propulsion system called hybrid propulsion is met as well, where the thrusters of DP systems are driven through the gear by mechanical engine or electric motor independent or both. For the sake of the necessity of limitation of total installed power on the ship may occurred problems with power distribution between the ship propulsion and industry part. It will especially concern those situations when we need to keep power supply to the industry part and there is a necessity to increase the power delivered to ship propulsion part for the purpose of keeping the ship position or heading. The primary task of power management system (PMS) is blackout prevention in ship energetic network and so power distribution to overcome critical conditions of it. Temporarily it may occur the worsening of positioning operation accuracy without any critical situations of industry part. The possibility of momentary overloading of energetic network is primary condition of safety. The critical duration of overloading is one minute. This is indispensable time for increasing the accessible power in the energetic system through switching on the next genset to work. It is a necessity of quick analysis in critical conditions to value what key-actions ought to do in the aim of overcoming emergency situations. The next one is a usage of energy storage devices. It is possible through AC/DC conversion. It was tried to find solutions of equalization the load of gensets to the ship electric energy demand.

Energy saving in data processing and communication systems.

The power management of ICT systems, that is, data processing (Dp) and telecommunication (Tlc) systems, is becoming a relevant problem in economical terms. Dp systems totalize millions of servers and associated subsystems (processors, monitors, storage devices, etc.) all over the world that need to be electrically powered. Dp systems are also used in the government of Tlc systems, which, besides requiring Dp electrical power, also require Tlc-specific power, both for mobile networks (with their cell-phone towers and associated subsystems: base stations, subscriber stations, switching nodes, etc.) and for wired networks (with their routers, gateways, switches, etc.). ICT research is thus expected to investigate into methods to reduce Dp- and Tlc-specific power consumption. However, saving power may turn into waste of performance, in other words, into waste of ICT quality of service (QoS). This paper investigates the Dp and Tlc power management policies that look at compromises between power saving and QoS.

New developments on DP systems

DP Systems are based on control, filtering and optimization solid theoretical background, and the technology related to sensors, actuation and computational systems are consolidated and reliable. Therefore, the offshore operations are increasingly supported by DP Systems since the 70’s. However, there are still space for new developments and innovative solutions to improve DP performance and to be applied to more complex offshore operations. This paper presents four research topics conducted by the Brazilian Universities and Petrobras related to the improvement of the DP Systems.

Cooperative Control applied to DP Systems – Numerical Analysis

The present paper addresses the development of a cooperative control based on the consensus control concepts applied to Ships with Dynamic Positioning Systems (DP). The objective of the cooperative control is to maintain constant the relative distance between the two tugboats. The benefits of this control will be evaluated by numerical simulation.

Thrust Ability Diagrams for Multi-Thruster Marine Vessels

For reliable fault-tolerant control, monitoring, and capability analysis of dynamically positioned vessel it is highly desirable to know the set of generalized force vectors possible to allocate between the thrusters in operation. Such a 3-dimensional set, referred as the Thrust Ability Diagram (TAD) may be quite complicated but is effectively approximated by unions of convex polytopes. In the present paper the methods of computation and visualization, as well as applications of TAD in the DP systems are discussed. We show that the calculation of TAD is a quite useful function of dynamic positioning system.

Experimental Analysis of a Thrust Allocation Algorithm for DP Systems Considering the Interference between Thrusters and Thruster-Hull

This paper presents the experimental analysis of the Thrust Allocation Algorithm considering the interference between thrusters and thruster-hull. The first objective is to formulate an allocation algorithm that considers the efficiency curve of the thrusters (in different azimuth positions due to interference phenomena) into the optimization process. The second objective is evaluating, through experiments, the effectiveness of this new algorithm.