Rapid and high resolution motion and tension measurements were made of a typical vertically tethered system, a caged deep-sea ROV, while it operated at sea. The system is essentially one-dimensional because only the vertical motions of the underwater platform and the ship were coherent, while horizontal motions of the platform were weak and incoherent with any component of motion of the ship. The natural frequency of the system is found to be within the frequency band of ship motion for most of its operating range and the platform response is weakly non-linear. This results in a vertical acceleration of the platform that is up to 2.2 times larger than that of the ship. Large vertical excursions of the ship produce momentary slack in the tether near the platform. At the instant prior to re-tensioning, the tether and platform are moving apart and upon re-tensioning, the inertia of the platform imparts a large strain—a snap load—in the tether. The resulting strain wave propagates to the surface with the characteristic speed (3870 ms⁻¹) of tensile waves in the tether. An extremely repeatable pattern of echoes is detectable at each end. Two models, a continuous (closed form) non-dimensional frequency domain model and a discrete finite-element time domain model are developed to represent vertically tethered systems subject to surface excitation. Both models accurately predicts the measured response, with slightly better accuracy in the discrete version. The continuous model shows that the response is governed by only two non-dimensional parameters. The continuous model is invalid for slack tether and inherently unable to predict snap loads. By slightly increasing the ship motion, the discrete model accurately reproduces the observed snap loads and their characteristics. Discrepancies between the predicted and measured response of the platform bring into question the concepts of a constant drag coefficient and a constant added mass for oscillatory flow around the platform. By adding a simple wake model to account for flow history, the error in the calculated platform motion and tension in the tether were reduced by almost a factor of 2. Passive ship-mounted and cage-mounted heave compensation systems were investigated with a view to reducing the cage motion and tension in the tether. Both systems were found to be effective and for reasonable parameters, they can reduce the motion of the cage and the tension in the tether by a factor of 2. Addition of either compensation system reduced the natural frequency of the system and extended the operating sea state of a cage ROV system. However, the characteristics of the compensation systems must be carefully chosen or the operational problems will be exacerbated. In particular, the natural frequency of higher modes may enter the waveband for deeper operating depths. During extreme sea states, the cage compensated system eliminated all snap loads. / Graduate

Thesis (M.S.)--Tufts University, 2002. / Submitted to the Dept. of Mechanical Engineering. Includes bibliographical references (leaves 122-123).

As the Navy continues its development of unmanned underwater vehicles, the need for total autonomous missions grows. Autonomous Underwater Vehicles (AUV) allow for advances in mine warfare, harbor reconnaissance, undersea warfare and more. Information can be collected from AUVs and downloaded into a ship or battle group.s network. As AUVs are developed it is clear forward-look sonar will be required to be able to detect obstacles in front of its search path. Common obstacles in the littoral environment include reefs and seawalls which an AUV will need to rise above to pass. This thesis examines the behavior and control system required for an AUV to maneuver over an obstacle in the vertical plane. Hydrodynamic modeling of a REMUS vehicle enables a series of equations of motion to be developed to be used in conjunction with a sliding mode controller to control the elevation of the AUV. A two-dimensional, 24o vertical scan forward look sonar with a range of 100 m is modeled for obstacle detection. Sonar mappings from geographic range-bearing coordinates are developed for use in MATLAB simulations. The sonar .image. of the vertical obstacle allows for an increasing altitude command that forces the AUV to pass safely over the obstacles at a reasonable rate of ascent and pitch angle. Once the AUV has passed over the obstacle, the vehicle returns to its regular search altitude. This controller is simulated over different types of obstacles. / US Navy (USN) author.

No description available.

A general analytical framework was established to investigate the scale-related variabilities in remote sensing. The variabilities were studied first by investigating canopy structure, canopy interaction with light, relation between spectral reflectance and plant phenological parameters. The variabilities simulated by the plant model were compared with the actual spectral data acquired by ground spectroradiometer and satellite sensors. The theoretical relation between orthogonal-basedtransform and Kahunen-Lo6ve transform was investigated in the vector space. The role of spectral indices in identifying the status of phenological parameters was briefly studied. The radiometric corrections of the remotely sensed data were carefully controlled to avoid the unwanted noise introduced by typical resampling/correction procedures from commercial operation. The non-linearity and sensor response corrections were applied to the spectral data as necessary. Variability analysis was conducted to illustrate the complexities of spectral variability embedded in the remotely sensed data. The information extraction in spatial frequency domain was investigated with emphasis in Fourier domain feature extraction. The Radon transform was introduced as the potential tool to enhance the spatial information of the Fourier transformed image. The adequacy of entropy and fractal dimension as image information measures was proved. A functional link between entropy and fractal dimension was established. The image information content was extracted using various first and second order statistics, entropy, and fractal dimension. Results were presented for different remote sensors based on the full image information content and specific agricultural ground features. The quality of spatial resampling algorithms was tested by investigating the capability to maintain image information in the resampled image. Finally, two applications utilizing this analytical framework were presented to show its potential in land-use classification and multiscale data fusion. / Graduation date: 1993

An Internet and Web Based Remote Micro-Controller System Jia-Sheng Hsieh¡¹ Whei-Min Lin¡¹¡¹ Institute of Electrical Engineering National Sun Yat-Sen University Abstract With the development of new technologies, extending the techniques from local control to remote control with the public communication media becomes worldwide issues. In the hardware aspect, this research designed the T-RMC (Twin-Remote Micro controller) system to reduce hardware cost. This Fore-Processor can simulate Programming Logical Controller (PLC), to accomplish function of data acquisition and data transmission. The design features low cost¡B high stability, with remote data transmission, and easy expansion. The system functions are now designed with one point to one point communication, so in the future work, this system will be expanded to become one point to multi-point or multi-point to multi-point control system. Anther topic of this thesis is to develop a GUI (Graphical User Interface) suitable for Internet based supervisory control systems. In addition, the thesis presents the use of some CGI (Common Gateway Interface) programs, and the technique of embedded G programming (Graphic programming) into the homepage. The operator can operate the system easily by using friendly GUI. Examples of two applications were used to show that the T-RMC system was accomplished successfully. The experimental results have demonstrated the capabilities of the supervisory control system through LAN or Internet. One is the Remote Multi-channel Analog/Digital Signal Acquisition System, and the other is the Internet-Based Remote Scheduling Agent System. These systems can manage and control the conventional household or industrial electric equipment, to achieve the goal of energy conservation. ¡¹Author ¡¹¡¹Advisor

ABSTRACT: With the progress of science development, the controls of various loads come into computerize gradually. Most of equipment makes use of programmable Logic Controller or Ethernet network in the past, which connect with computer. It is mature in industrial applications, but still unsuitable in the general monitoring system . The project focuses on this problem to provide a complete solution. The fundamental structure of system runs in the environment of popular windows by personal computer, using high-level interface program between human being and machine. The operator can be easy to operate system by using high-level interface program language. It makes use of series-port output and input signals via cable to specific module, and supplies interface program between human and machine. Consequently, remote equipment can be controlled to achieve expected purpose.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Richard C. Olsen, David M. Task. Includes bibliographical references (p. 141-142). Also available online.

Thesis (M.Sc.)--York University, 2008. Graduate Programme in Science. / Typescript. Includes bibliographical references (leaves 156-160). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR45937

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Anthony J. Healey. Includes bibliographical references (p. 99-101). Also available online.