Pemahaman pelajar tingkatan lima katering terhadap bab kaedah memasak dalam mata pelajaran teknologi katering

Bab Kaedah Memasak merupakan salah satu bab yang penting dalam mata pelajaran Teknologi Katering. Faktor terpenting adalah memastikan pelajar menguasai serta memahami konsepnya adalah melalui proses pengajaran dan pembelajaran yang betul. Tinjauan awal di Sekolah Menengah Teknik yang menawarkan Kursus Katering, menunjukkan bahawa kebanyakan pelajar sukar untuk menguasai dan memahami bab tersebut. Berdasarkan hasil tinjauan , pengkaji ingin mengenalpasti pemasalahan dalam memahami bab tersebut. Di samping itu juga, pengkaji ingin mengenalpasti adakah pencapaian pelajar dalam PMR, minat, motivasi dan gaya pembelajaran mempengaruhi pemahaman pelajar, Kajian rintis telah dilakukan terhadap 10 orang responden dengan nilai alpha 0.91. Ini menunjukkan kebolehpercayaan terhadap kajian di jalankan adalah tinggi. Responden adalah terdiri daripada 30 orang pelajar Tingkatan Lima (ERT) Sekolah Menengah Teknik Muar, Johor. Keputusan skor min keseluruhan menunjukkan pelajar berminat dan mempunyai motivasi ynag baik dalam bidang ini. Namun begitu, gaya pembelajaran yang diamalkan tidak sesuai dan antara pemyebab wujudnya pemasalahan dalam memahami bab Kaedah Memasak. Ujian kolerasi menunjukkan bahawa tidak terdapat sebarang hubungan signifikan antara pencapaian PMR pelajar dengan pemahaman bab tersebut. Sementara minat, motivasi dan gaya pembelajaran membuktikan ada hubungan signifikan dengan pemahaman pelajar dalam bab Kaedah Memasak

Cooperative algorithms for a team of autonomous underwater vehicles

Ph.DDOCTOR OF PHILOSOPH

MODELLING VIRTUAL ENVIRONMENT FOR ADVANCED NAVAL SIMULATION

This thesis proposes a new virtual simulation environment designed as element of an interoperable federation of simulator to support the investigation of complex scenarios over the Extended Maritime Framework (EMF). Extended Maritime Framework is six spaces environment (Underwater, Water surface, Ground, Air, Space, and Cyberspace) where parties involved in Joint Naval Operations act. The amount of unmanned vehicles involved in the simulation arise the importance of the Communication modelling, thus the relevance of Cyberspace. The research is applied to complex cases (one applied to deep waters and one to coast and littoral protection) as examples to validate this approach; these cases involve different kind of traditional assets (e.g. satellites, helicopters, ships, submarines, underwater sensor infrastructure, etc.) interact dynamically and collaborate with new autonomous systems (i.e. AUV, Gliders, USV and UAV). The use of virtual simulation is devoted to support validation of new concepts and investigation of collaborative engineering solutions by providing a virtual representation of the current situation; this approach support the creation of dynamic interoperable immersive framework that could support training for Man in the Loop, education and tactical decision introducing the Man on the Loop concepts. The research and development of the Autonomous Underwater Vehicles requires continuous testing so a time effective approach can result a very useful tool. In this context the simulation can be useful to better understand the behaviour of Unmanned Vehicles and to avoid useless experimentations and their costs finding problems before doing them. This research project proposes the creation of a virtual environment with the aim to see and understand a Joint Naval Scenario. The study will be focusing especially on the integration of Autonomous Systems with traditional assets; the proposed simulation deals especially with collaborative operation involving different types of Autonomous Underwater Vehicles (AUV), Unmanned Surface Vehicles (USV) and UAV (Unmanned Aerial Vehicle). The author develops an interoperable virtual simulation devoted to present the overall situation for supervision considering also the sensor capabilities, communications and mission effectiveness that results dependent of the different asset interaction over a complex heterogeneous network. The aim of this research is to develop a flexible virtual simulation solution as crucial element of an HLA federation able to address the complexity of Extended Maritime Framework (EMF). Indeed this new generation of marine interoperable simulation is a strategic advantage for investigating the problems related to the operational use of autonomous systems and to finding new ways to use them respect to different scenarios. The research deal with the creation of two scenarios, one related to military operations and another one on coastal and littoral protection where the virtual simulation propose the overall situation and allows to navigate into the virtual world considering the complex physics affecting movement, perception, interaction and communication. By this approach, it becomes evident the capability to identify, by experimental analysis within the virtual world, the new solutions in terms of engineering and technological configuration of the different systems and vehicles as well as new operational models and tactics to address the specific mission environment. The case of study is a maritime scenario with a representation of heterogeneous network frameworks that involves multiple vehicles both naval and aerial including AUVs, USVs, gliders, helicopter, ships, submarines, satellite, buoys and sensors. For the sake of clarity aerial communications will be represented divided from underwater ones. A connection point for the latter will be set on the keel line of surface vessels representing communication happening via acoustic modem. To represent limits in underwater communications, underwater signals have been considerably slowed down in order to have a more realistic comparison with aerial ones. A maximum communication distance is set, beyond which no communication can take place. To ensure interoperability the HLA Standard (IEEE 1516 evolved) is adopted to federate other simulators so to allow its extensibility for other case studies. Two different scenarios are modelled in 3D visualization: Open Water and Port Protection. The first one aims to simulate interactions between traditional assets in Extended Maritime Framework (EMF) such as satellite, navy ships, submarines, NATO Research Vessels (NRVs), helicopters, with new generation unmanned assets as AUV, Gliders, UAV, USV and the mutual advantage the subjects involved in the scenario can have; in other word, the increase in persistence, interoperability and efficacy. The second scenario models the behaviour of unmanned assets, an AUV and an USV, patrolling a harbour to find possible threats. This aims to develop an algorithm to lead patrolling path toward an optimum, guaranteeing a high probability of success in the safest way reducing human involvement in the scenario. End users of the simulation face a graphical 3D representation of the scenario where assets would be represented. He can moves in the scenario through a Free Camera in Graphic User Interface (GUI) configured to entitle users to move around the scene and observe the 3D sea scenario. In this way, players are able to move freely in the synthetic environment in order to choose the best perspective of the scene. The work is intended to provide a valid tool to evaluate the defencelessness of on-shore and offshore critical infrastructures that could includes the use of new technologies to take care of security best and preserve themselves against disasters both on economical and environmental ones

Underwater Vehicles

For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties

Development of Robust Control Strategies for Autonomous Underwater Vehicles

The resources of the energy and chemical balance in the ocean sustain mankind in many ways. Therefore, ocean exploration is an essential task that is accomplished by deploying Underwater Vehicles. An Underwater Vehicle with autonomy feature for its navigation and control is called Autonomous Underwater Vehicle (AUV). Among the task handled by an AUV, accurately positioning itself at a desired position with respect to the reference objects is called set-point control. Similarly, tracking of the reference trajectory is also another important task. Battery recharging of AUV, positioning with respect to underwater structure, cable, seabed, tracking of reference trajectory with desired accuracy and speed to avoid collision with the guiding vehicle in the last phase of docking are some significant applications where an AUV needs to perform the above tasks. Parametric uncertainties in AUV dynamics and actuator torque limitation necessitate to design robust control algorithms to achieve motion control objectives in the face of uncertainties. Sliding Mode Controller (SMC), H / μ synthesis, model based PID group controllers are some of the robust controllers which have been applied to AUV. But SMC suffers from less efficient tuning of its switching gains due to model parameters and noisy estimated acceleration states appearing in its control law. In addition, demand of high control effort due to high frequency chattering is another drawback of SMC. Furthermore, real-time implementation of H / μ synthesis controller based on its stability study is restricted due to use of linearly approximated dynamic model of an AUV, which hinders achieving robustness. Moreover, model based PID group controllers suffer from implementation complexities and exhibit poor transient and steady-state performances under parametric uncertainties. On the other hand model free Linear PID (LPID) has inherent problem of narrow convergence region, i.e.it can not ensure convergence of large initial error to zero. Additionally, it suffers from integrator-wind-up and subsequent saturation of actuator during the occurrence of large initial error. But LPID controller has inherent capability to cope up with the uncertainties. In view of addressing the above said problem, this work proposes wind-up free Nonlinear PID with Bounded Integral (BI) and Bounded Derivative (BD) for set-point control and combination of continuous SMC with Nonlinear PID with BI and BD namely SM-N-PID with BI and BD for trajectory tracking. Nonlinear functions are used for all P,I and D controllers (for both of set-point and tracking control) in addition to use of nonlinear tan hyperbolic function in SMC(for tracking only) such that torque demand from the controller can be kept within a limit. A direct Lyapunov analysis is pursued to prove stable motion of AUV. The efficacies of the proposed controllers are compared with other two controllers namely PD and N-PID without BI and BD for set-point control and PD plus Feedforward Compensation (FC) and SM-NPID without BI and BD for tracking control. Multiple AUVs cooperatively performing a mission offers several advantages over a single AUV in a non-cooperative manner; such as reliability and increased work efficiency, etc. Bandwidth limitation in acoustic medium possess challenges in designing cooperative motion control algorithm for multiple AUVs owing to the necessity of communication of sensors and actuator signals among AUVs. In literature, undirected graph based approach is used for control design under communication constraints and thus it is not suitable for large number of AUVs participating in a cooperative motion plan. Formation control is a popular cooperative motion control paradigm. This thesis models the formation as a minimally persistent directed graph and proposes control schemes for maintaining the distance constraints during the course of motion of entire formation. For formation control each AUV uses Sliding Mode Nonlinear PID controller with Bounded Integrator and Bounded Derivative. Direct Lyapunov stability analysis in the framework of input-to-state stability ensures the stable motion of formation while maintaining the desired distance constraints among the AUVs

Energy efficient navigational methods for autonomous underwater gliders in surface denied regions

Autonomous underwater gliders routinely perform long duration profiling missions while characterizing the chemical, physical and biological properties of the water column. These measurements have opened up new ways of observing the ocean’s processes and their interactions with the atmosphere across time and length scales which were not previously possible. Extending these observations to ice-covered regions is of importance due to their role in ocean circulation patterns, increased economic interest in these areas and a general sparsity of observations. This thesis develops an energy optimal depth controller, a terrain aided navigation method and a magnetic measurement method for an autonomous underwater glider. A review of existing methods suitable for navigation in underwater environments as well as the state of the art in magnetic measurement and calibration techniques is also presented. The energy optimal depth controller is developed and implemented based on an integral state feedback controller. A second order linear time invariant system is identified from field data and used to compute the state feedback controller gains through an augmented linear quadratic regulator. The resulting gains and state feedback controller methodology are verified through field trials and found to control the depth of the vehicle while losing less than one percent of the vehicle’s propulsive load to control inputs or lift induced drag. The terrain aided navigation method is developed based on a jittered bootstrap algorithm which is a type of particle filter that makes use of the vehicle’s deadreckoned navigation solution, onboard altimeter and a local digital parameter model (DPM). An evaluation is performed through post-processing offline location estimates from field trials which took place in Holyrood Arm, Newfoundland, overlapping a previously collected DPM. During the post-processing of these trials, the number of particles, jittering variance and DPM grid cell size were varied. Online open loop field trials were performed through integrating a new single board computer. In these trials the localization error remained bounded and improved on the dead reckoning error, validating the filter despite the large dead-reckoned errors, single beam altitude measurements, and short test duration. Terrain aided navigation methods perform poorly in regions of flat terrain or in deep water where the seafloor is beyond the range of the altimeter. Magnetic measurements of the Earth’s main field have been proposed previously to augment terrain aided navigation algorithms in these regions. To this end a low power magnetic instrumentation suite for an underwater glider has been developed. Two calibration methodologies were also developed and compared against regional digital models of the magnetic field. The calibration methods include one for which the actuators in the vehicle were kept in fixed locations and a second for which the calibration coefficients were parameterized for the actuator locations. Both methods were found to agree with the low frequency content in the a-priori regional magnetic anomaly grids

The flux measure of influence in engineering networks

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 109-115).The objective of this project is to characterize the influence of individual nodes in complex networks. The flux metric developed here achieves this goal by considering the difference between the weighted outdegree and indegree of a node. This technique differentiates among nodes that traditional centrality measures treat as identical units. The behavior and proper interpretation of the flux metric are demonstrated on a variety of weighted and directed networks. Simulations of fluid flow, opinion sharing, epidemic dynamics, and resource allocation reveal the practical capabilities of the flux metric. An engineering design challenge may also be framed as a network analysis problem so that the the flux metric contributes to understanding the relationships among the system's subcomponents and objectives. A case study that investigates the design of autonomous underwater vehicles (AUVs) for use in the offshore oil and gas industry demonstrates these insights. In all of the applications explored here, the flux metric consistently emerges as a reliable indicator of the influence of a node.by Kyle Michael Schwing.S.M

Human Interaction with Robot Swarms: A Survey

Recent advances in technology are delivering robots of reduced size and cost. A natural outgrowth of these advances are systems comprised of large numbers of robots that collaborate autonomously in diverse applications. Research on effective autonomous control of such systems, commonly called swarms, has increased dramatically in recent years and received attention from many domains, such as bioinspired robotics and control theory. These kinds of distributed systems present novel challenges for the effective integration of human supervisors, operators, and teammates that are only beginning to be addressed. This paper is the first survey of human–swarm interaction (HSI) and identifies the core concepts needed to design a human–swarm system. We first present the basics of swarm robotics. Then, we introduce HSI from the perspective of a human operator by discussing the cognitive complexity of solving tasks with swarm systems. Next, we introduce the interface between swarm and operator and identify challenges and solutions relating to human–swarm communication, state estimation and visualization, and human control of swarms. For the latter, we develop a taxonomy of control methods that enable operators to control swarms effectively. Finally, we synthesize the results to highlight remaining challenges, unanswered questions, and open problems for HSI, as well as how to address them in future works