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A Novel Contour Tracing Algorithm for Object Shape Reconstruction Using Parametric Curves

Computers, Materials & Continua 2023年第4期75卷 331-350页

作者： Nihat Arslan Kali Gurkahraman Defence Technology Programme Sivas University of Science and TechnologySivas58070Turkey Department of Computer Engineering Sivas Cumhuriyet UniversitySivas58140Turkey

Parametric curves such as Bézier and B-splines, originally developedfor the design of automobile bodies, are now also used in image processing andcomputer vision. For example, reconstructing an object shape in an image,including different translations, scales, and orientations, can be performedusing these parametric curves. For this, Bézier and B-spline curves can be generatedusing a point set that belongs to the outer boundary of the object. Theresulting object shape can be used in computer vision fields, such as searchingand segmentation methods and training machine learning algorithms. Theprerequisite for reconstructing the shape with parametric curves is to obtainsequentially the points in the point set. In this study, a novel algorithm hasbeen developed that sequentially obtains the pixel locations constituting theouter boundary of the object. The proposed algorithm, unlike the methods inthe literature, is implemented using a filter containing weights and an outercircle surrounding the object. In a binary format image, the starting point ofthe tracing is determined using the outer circle, and the next tracing movementand the pixel to be labeled as the boundary point is found by the filter ***, control points that define the curve shape are selected by reducing thenumber of sequential points. Thus, the Bézier and B-spline curve equationsdescribing the shape are obtained using these points. In addition, differenttranslations, scales, and rotations of the object shape are easily provided bychanging the positions of the control points. It has also been shown that themissing part of the object can be completed thanks to the parametric curves.

关键词： Contour tracing algorithm bézier curve B-spline curve object shape reconstruction

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Understanding the service desk: Applied forecasting and analytics approach

Understanding the service desk: Applied forecasting and anal...

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2017 IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 2017

作者： Jie, Ng Jun Enterprise IT Programme Centre Defence Science and Technology Agency Singapore

ISBN: (纸本)9781538609484

In this paper, the study aimed to identify the best forecasting model to represent I-Helpdesk, service desk of an Information technology (IT) project under the Singapore's Ministry of defence (MINDEF), in the aspect of Service Requests management. defence Science and technology Agency (DSTA) support MINDEF users in the area of technical consultancy and project management areas such as resource allocation management for IT service delivery and excellence. To achieve an overall aim of better service delivery for their system users, we intend to answer questions such as: How should we plan the helpdesk staffing for the next week/month? © 2017 IEEE.

关键词： Forecasting

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Analysis of RFID mutual authentication protocols

Analysis of RFID mutual authentication protocols

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2009 IEEE Wireless Communications and Networking Conference, WCNC 2009

作者： Guo, Charng Rang Infocomm Infrastructure Programme Centre Defence Science and Technology Agency Singapore

ISBN: (纸本)9781424429486

In order to secure RFID transactions, an authentication scheme has originally been included as part of the "EPC Gen2" industrial standard. This scheme, however, has been found to have some weaknesses. To overcome such weaknesses, some authors have proposed new schemes to improve its security. Two of the latest proposals are the Lim-Li protocol and the Konidala-Kim-Kim protocol presented in 2007. We propose an attack that can be applied to both these protocols. In both cases, the Search Space for the password(s) used have been drastically reduced, which effectively breaks the security of these protocols. © 2009 IEEE.

关键词： Radio frequency identification (RFID)

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Aircraft seating - Boarding mass investigations: Understanding the implications of exceeding design and qualification limits 55

Aircraft seating - Boarding mass investigations: Understandi...

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55th Annual SAFE Symposium 2017

作者： Butcher, Richard Aircrew Systems Research Programme Defence Science and Technology Laboratory United Kingdom

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A flexible virtual structure formation keeping control for fixed-wing UAVs

A flexible virtual structure formation keeping control for f...

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9th IEEE International Conference on Control and Automation, ICCA 2011

作者： Low, Chang Boon Ng, Quee San DSO National Laboratories INFO Division Manned-Unmanned Programme 27 Medical Drive Singapore 117510 Singapore DSTA Defence Science and Technology Agency Singapore

ISBN: (纸本)9781457714757

This paper presents a flexible virtual structure (V-S) formation control schemes for nonholonomic fixed-wing UAVs. In contrast to geometric rigid V-S formation control schemes, flexible V-S formation scheme enables a formation to turn smoothly, and hence allows the UAVs in the formation to follow the desired heading profile of the planned formation trajectory. In this work, trajectory generation algorithms are developed to compute the coordinated formation reference trajectories where each of these reference trajectories is executed by our recently proposed trajectory tracking control scheme. Results are also developed to assess the feasibility of the formation trajectory based on operating envelopes of a given UAV. These results provide basic tools for understanding and implementing the formation keeping control scheme according to the fixed-wing UAV's capability. The effectiveness of the V-S formation control scheme is validated using nonlinear six degree-of-freedom (6DOF) fixed-wing UAV models and simulation results are presented. © 2011 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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A generalized method for environmental surveillance by remote probing

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Radio Science 1978年第2期13卷 233-244页

作者： Gjessing, Dag T. Norwegian Defence Research Establishment P. O. Box 25 N-2007 Kjeller Norway Presently with Remote Probing Technology Programme Royal Norwegian Council for Scientific and Industrial Research.

New components and methods in the field of microwave techniques, electrooptics, computer technology, statistics, and electromagnetics open new and very interesting possibilities with regard to detection and identification problems. The current contribution suggests with varying degrees of substantiation a set of unified detection methods which may conceivably have an impact on several application areas (environmental surveillance, detection/identification of specific objects). The basic principle is the following. Most of the existing detection/identification systems do not make optimum use of all the a priori information that one generally is in possession of with regard to the target of interest. Knowing the geometrical shape of the target of interest and its molecular surface structure (e.g., structure of paint), an illumination function can be structured (matched filter concept) which gives optimum system sensitivity (minimum receiver bandwidth) with respect to the target of interest at the expense of the sensitivity for background objects (interferents). Theoretical results are given in the paper for a limited number of geometrical objects and for two different molecular surface compositions. It is shown that the system sensitivity and identification capability can be improved considerably using the suggested matched filter illumination technique. Copyright 1978 by the American Geophysical Union.

关键词： Microwave filters Receivers Fingerprint recognition Lighting Sensitivity

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Analysis of RFID Mutual Authentication Protocols

Analysis of RFID Mutual Authentication Protocols

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IEEE Conference on Wireless Communications and Networking

作者： Charng Rang Guo Infocomm Infrastructure Programme Centre Defence Science and Technology Agency Singapore

In order to secure RFID transactions, an authentication scheme has originally been included as part of the "EPC Gen2" industrial standard. This scheme, however, has been found to have some weaknesses. To overcome such weaknesses, some authors have proposed new schemes to improve its security. Two of the latest proposals are the Lim-Li protocol and the Konidala-Kim-Kim protocol presented in 2007. We propose an attack that can be applied to both these protocols. In both cases, the search space for the password(s) used have been drastically reduced, which effectively breaks the security of these protocols.

关键词： Radiofrequency identification Authentication Access protocols Proposals Data security Communications Society Databases

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Proposing a novel low-power high-speed mixed GDI full adder topology

Proposing a novel low-power high-speed mixed GDI full adder ...

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International Conference on Power, Control and Embedded Systems, ICPCES 2010

作者： Agrawal, Adarsh Kumar Mishra, Shivshankar Nagaria, R.K. BSNL Mumbai India Programme 'Ad' Defence Research and Development Organization Hyderabad-500058 India Electronics and Communication Engineering Department Motilal Nehru National Institute of Technology Allahabad-211004 India

ISBN: (纸本)9781424485420

This paper deals with the implementation of full adder chains by mixing different CMOS full adder topologies. The proposed approach is based on cascading fast Gate Diffusion Input (GDI) Full Adders interrupted by static gate having driving capability, such as inverter, thus exploiting the intrinsic low power consumption of such topologies. The results obtained show that the proposed mixed-topology approach based on GDI adders is capable of very low-power consumption and a very high-speed. This also enables a high degree of design freedom, given that the same (mixed) topology can be used for a wide range of applications. This greater flexibility also affords a significant reduction in the design effort. Delay and power has been evaluated by HSPICE simulation using TSMC 0.18?m CMOS technology considering minimum power design. The simulation results reveal better delay and power performance of proposed topology as compared to existing topologies at 1.8V supply voltage. ©2010 IEEE.

关键词： Adders

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Future Large Aircraft (FLA): European collaboration or buying off‐the‐shelf?

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RUSI Journal 1993年第4期138卷 67-69页

作者： Appleby, John Gilbert, Gordon Technology and Defence Procurement Programme RUSI United Kingdom

The aerospace industry has been identified as a key player in the restructuring of the European defence industry as a whole and the British government has seemed keen to support the role of the UK aerospace industry in this process. However, the decision to withdraw from the European attempt to develop a new alternative transport aircraft and to favour an American upgrade of the C130 Hercules has brought this commitment into question. John Appleby and Gordon Gilbert examine the issues and options surrounding this dilemma and its implications. © Taylor & Francis Group, LLC.

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Numerical investigation on effect of air/fuel ratio on ramjet dump combustor performance

Numerical investigation on effect of air/fuel ratio on ramje...

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AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference

作者： Singh Thangadurai, G. Raja Subhash Chandran, B.S. Babu, V. Sundararajan, T. Defence Research and Development Laboratory Hyderabad 500058 India Department of Mechanical Engineering Indian Institute of Technology Madras 600036 India Programme PJ - 10 Ramjet Propulsion Division Thermodynamics and Combustion Engineering Laboratory

ISBN: (纸本)1563478188

Ramjets are the preferred air-breathing engines at high supersonic speeds. The combustion phenomenon in ramjet combustors is very complex. The complexities arise due to liquid - gas phase coupling, high temperature variation and intricate flame chemistry. Numerical simulation of flow environment in ramjet combustors is formidably challenging because the flow process comprises simultaneous momentum, heat and mass transport processes. Flow simulation software FLUENT is used to simulate the flow environment in a ramjet dump combustor with two side inlets 90° apart by solving the governing equations with appropriate boundary conditions. The turbulent flow features are predicted by employing standard k - Ε equations based on generalized Boussinesq eddy viscosity concept. Eulerian approach is used to model the gas phase heat and mass transfer. Fuel particles are tracked using Lagrangian formulation. In liquid phase modelling, the momentum, energy and species balances are carried out by treating the droplet as a lumped system. Probability Density Function (PDF) approach is employed to describe the turbulent fluctuations in the mixture fraction. Predictions of temperature inside a ramjet combustor were compared with the limited experimental data available and reasonable matching was observed. A detailed study has been carried out on the baseline combustor geometry under consideration for air/fuel ratios of 10, 15 and 30 and the results are discussed in this paper.

关键词： Combustors

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