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2007

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Articles 1261 - 1290 of 1355

Full-Text Articles in Computer Sciences

Iterated Weaker-Than-Weak Dominance, Shih-Fen Cheng, Michael P. Wellman Jan 2007

Iterated Weaker-Than-Weak Dominance, Shih-Fen Cheng, Michael P. Wellman

Research Collection School Of Computing and Information Systems

We introduce a weakening of standard gametheoretic δ-dominance conditions, called dominance, which enables more aggressive pruning of candidate strategies at the cost of solution accuracy. Equilibria of a game obtained by eliminating a δ-dominated strategy are guaranteed to be approximate equilibria of the original game, with degree of approximation bounded by the dominance parameter. We can apply elimination of δ-dominated strategies iteratively, but the for which a strategy may be eliminated depends on prior eliminations. We discuss implications of this order independence, and propose greedy heuristics for determining a sequence of eliminations to reduce the game as far as possible …

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A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou Jan 2007

A Variable Gain Pi Controller Used For Speed Control Of A Direct Torque Neuro Fuzzy Controlled Induction Machine Drive, A. Miloudi, Eid A. Al-Radadi, Azeddine Draou

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an original variable gain PI (VGPI) controller for speed control of a direct torque neuro fuzzy controlled (DTNFC) induction motor drive. First, a VGPI speed controller is designed to replace the classical PI controller in a conventional direct torque controlled induction motor drive. Its simulated performances are then compared to those of a classical PI controller. Then, a direct torque neuro fuzzy control (DTNFC) for a voltage source PWM inverter fed induction motor drive is presented. This control scheme uses the stator flux amplitude and the electromagnetic torque errors through an adaptive NF inference system (ANFIS) to …

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Analysis Of Finline Structures With Consideration Of Metallization Thickness And Substrate Mounting Grooves, Abderrahmane Ouadi, Hadj Bourdoucen Jan 2007

Analysis Of Finline Structures With Consideration Of Metallization Thickness And Substrate Mounting Grooves, Abderrahmane Ouadi, Hadj Bourdoucen

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, mathematical analysis and numerical calculations of main parameters of finline structures with finite metallization thickness and substrate mounting grooves are developed based on the Method of Lines (MoL). The results obtained provide confirmation of the validity of the technique used and prove its simplicity and adequacy for treating different types of planar structures mainly finline based structures. Unilateral and bilateral finlines including practical parameters, such as metallization thickness and grooves' depths, have been investigated. The effect of these two parameters have been discussed based on realistic configurations and the results show that, at higher frequencies, the grooves …

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A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇ Jan 2007

A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Seismo-electromagnetic precursory-based earthquake prediction studies are criticized in terms of their scientific content, problem complexity, signal excitation and propagation, causal relations with earthquakes, and public awareness and expectations. One aim is to trigger a new debate on this hot topic in the Electromagnetic Society.

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New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska Jan 2007

New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska

Turkish Journal of Electrical Engineering and Computer Sciences

Precise calculation of parameters of thermoelectric modules and thermoelectric devices under operating conditions by present methods is very difficult. In this study, a new method is developed to calculate all parameters of thermoelectric modules. This new method makes it possible to determine the dynamic parameters of a real thermoelectric module operated under different working regimes. Measurement of thermoemf created by an operating module is the basis of this new method. An unloaded thermoelectric module, whose dynamic output parameters are necessary in the design of a medical helmet for the cooling of brain, has been investigated using this new method. A …

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Data Mining And Costas Arrays, Konstantinos Drakakis Jan 2007

Data Mining And Costas Arrays, Konstantinos Drakakis

Turkish Journal of Electrical Engineering and Computer Sciences

Costas arrays are used in RADAR (and SONAR) engineering to represent frequency-hopping patterns that optimize the RADAR's performance. In this work, using all available Costas arrays up to and including order 26, as well as data mining techniques, we investigate how the Costas property and the balance of signs in the difference triangle of a permutation are related. Our conclusion is that there is sufficient evidence to believe that the mechanism responsible for the formation of Costas arrays changes from low to high orders.

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Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba Jan 2007

Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we present a simple and effective signature verification method that depends only on the raw binary pixel intensities and avoids using complex sets of features. The method looks at the signature verification problem as a graph matching problem. The method is tested using genuine and forgery signatures produced by five subjects. An equal error rate of 26.7% and 5.6% was achieved for skilled and random forgeries, respectively. A positive property of our algorithm is that the false acceptance rate of random forgeries vanishes at the point of equal false rejection and skilled forgery false acceptance rates. Keeping …

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Umts-Hsdpa In High Altitude Platforms (Haps) Communications, Bazil Taha Ahmed, Miguel Calvo Ramon, Leandro De Haro-Ariet Jan 2007

Umts-Hsdpa In High Altitude Platforms (Haps) Communications, Bazil Taha Ahmed, Miguel Calvo Ramon, Leandro De Haro-Ariet

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, the performance of HAPs (High Altitudes Platforms) UMTS HSDPA (High Speed Downlink Packet Access) is studied for different HAPs height h, different cells radius R and two directions (0° and 30°) within the cell. The network under study is assumed to have 61 ground cells. It is noticed that, for urban zone users, the effective range is lower than the effective range for users in rural zones for a given modulation scheme. Also it is noticed that in rural zone, the HSDPA can support higher modulation schemes. It is noticed that, when 80% of the base station …

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A Review Of Studies In Swarm Robotics, Levent Bayindir, Erol Şahi̇n Jan 2007

A Review Of Studies In Swarm Robotics, Levent Bayindir, Erol Şahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Swarm robotics is a new approach to the coordination of large numbers of relatively simple robots. The approach takes its inspiration from the system-level functioning of social insects which demonstrate three desired characteristics for multi-robot systems: robustness, flexibility and scalability. In this paper we have presented a preliminary taxonomy for swarm robotics and classified existing studies into this taxonomy after investigating the existing surveys related to swarm robotics literature. Our parent taxonomic units are modeling, behavior design, communication, analytical studies and problems. We are classifying existing studies into these main axes. Since existing reviews do not have enough number of …

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Aggregation, Foraging, And Formation Control Of Swarms With Non-Holonomic Agents Using Potential Functions And Sliding Mode Techniques, Veysel Gazi̇, Bariş Fi̇dan, Y. Si̇nan Hanay, İlter Köksal Jan 2007

Aggregation, Foraging, And Formation Control Of Swarms With Non-Holonomic Agents Using Potential Functions And Sliding Mode Techniques, Veysel Gazi̇, Bariş Fi̇dan, Y. Si̇nan Hanay, İlter Köksal

Turkish Journal of Electrical Engineering and Computer Sciences

In this article we consider the aggregation, foraging, and formation control of swarms whose agents are moving in 2-dimensions with non-holonomic unicycle agent dynamics. We approach these problems using artificial potentials and sliding mode control. The main contribution is extension of the recent results (mainly for aggregation) in the literature based on a similar approach for simple integrator agent dynamics models to a significantly more realistic and more difficult setting with non-holonomic unicycle agent dynamics models. In particular, we design continuous-time control schemes via a constructive analysis based on artificial potential functions and sliding mode control techniques. The effectiveness of …

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Aggregation In Swarm Robotic Systems: Evolution And Probabilistic Control, Onur Soysal, Erki̇n Bahçeci̇, Erol Şahi̇n Jan 2007

Aggregation In Swarm Robotic Systems: Evolution And Probabilistic Control, Onur Soysal, Erki̇n Bahçeci̇, Erol Şahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

In this study we investigate two approachees for aggregation behavior in swarm robotics systems: Evolutionary methods and probabilistic control. In first part, aggregation behavior is chosen as a case, where performance and scalability of aggregation behaviors of perceptron controllers that are evolved for a simulated swarm robotic system are systematically studied with different parameter settings. Using a cluster of computers to run simulations in parallel, four experiments are conducted varying some of the parameters. Rules of thumb are derived, which can be of guidance to the use of evolutionary methods to generate other swarm robotic behaviors as well. In the …

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A Vrp-Based Route Planning For A Mobile Robot Group, Osman Parlaktuna, Aydin Si̇pahi̇oğlu, Ahmet Yazici Jan 2007

A Vrp-Based Route Planning For A Mobile Robot Group, Osman Parlaktuna, Aydin Si̇pahi̇oğlu, Ahmet Yazici

Turkish Journal of Electrical Engineering and Computer Sciences

In this study, a vehicle routing problem-based approach is presented to construct non-intersecting routes for the members of a mobile robot team. It is assumed that each robot starts from a central location such as the charging point, completes its route and returns to the starting location. The proposed method consists of three algorithms: a sweep algorithm determines the position of each node in clockwise (or counter clockwise) manner with respect to the starting location; savings algorithm calculates the saving obtained by adding a node to the route of a robot; Dijkstra's shortest path algorithm is used to calculate the …

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Design And Implementation Of An Ad-Hoc Routing Protocol For Mobile Robots, Carlos Agüero, Jose M. Canas, Miguel Ortu˜No, Vicente Matellan Jan 2007

Design And Implementation Of An Ad-Hoc Routing Protocol For Mobile Robots, Carlos Agüero, Jose M. Canas, Miguel Ortu˜No, Vicente Matellan

Turkish Journal of Electrical Engineering and Computer Sciences

Mobile robots need to be able to communicate among themselves, as well as with hosts participating in the task that they are all involved in. Wired networks are obviously not suitable for mobile robots. Current wireless networks based on a fixed infrastructure (GSM, WiFi, etc.) to route packets may not be suitable because this infrastructure does not cover every place and the requirements of its resources. The best choice for mobile robots are Ad-Hoc networks, which are wireless and do not need a fixed infrastructure. This article describes PERA, a complete communications library including link, net, and transport layers for …

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A Communication Module And Tdma Scheduling For A Swarm Of Small Submarines, Ram Somaraju, Felix Schill Jan 2007

A Communication Module And Tdma Scheduling For A Swarm Of Small Submarines, Ram Somaraju, Felix Schill

Turkish Journal of Electrical Engineering and Computer Sciences

Swarming algorithms usually require fast and reliable local information distribution among neighbouring nodes. Additionally, many applications also require global information distribution in the shortest possible time. We show that communication links with a range which is small compared to the size of the swarm offer many advantages. We propose a system using low frequency radio communication as a viable alternative to acoustic communication. A time division multiple access algorithm is presented together with results from simulations. The presented system can be effectively used in large scale swarms of small submersibles.

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Using Angle Of Arrival (Bearing) Information For Localization In Robot Networks, Tolga Eren Jan 2007

Using Angle Of Arrival (Bearing) Information For Localization In Robot Networks, Tolga Eren

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, we consider using angle of arrival information (bearing) for localization in robot networks. The essential property we require in this paper is that a node can infer heading information from its neighbors. We address the uniqueness of network localization solutions by the theory of globally rigid graphs. We show that while the parallel rigidity problem for formations with bearings is isomorphic to the distance case, the global rigidity of the formation is simpler (in fact identical to the simpler rigidity case) for a network with bearings, compared to formations with distances. We provide the conditions of localization …

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A Novel Method For Load Flow Analysis Of Unbalanced Three-Phase Radial Distribution Networks, Masoud Aliakbar Golkar Jan 2007

A Novel Method For Load Flow Analysis Of Unbalanced Three-Phase Radial Distribution Networks, Masoud Aliakbar Golkar

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a novel method for load flow analysis in radially operated 3-phase distribution networks without solving the well-known conventional load flow equations. The method can be applied for distribution systems in which the loads are unbalanced. As the size of matrix used is very small compared to those in conventional methods, the amount of memory used is very small, the speed is very high, and the relative speed of calculation increases with the size of the system. The method was applied to some practical networks and the results show the superiority of this method over the conventional ones. …

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Study Of The Warranty Cost Model For Software Reliability With An Imperfect Debugging Phenomenon, D.R. Prince Williams Jan 2007

Study Of The Warranty Cost Model For Software Reliability With An Imperfect Debugging Phenomenon, D.R. Prince Williams

Turkish Journal of Electrical Engineering and Computer Sciences

Software reliability is one of the most important characteristics of software quality. Its measurement and management technologies employed during the software life-cycle are essential for producing and maintaining quality/reliable software systems. Herein, we discuss a modified approach to calculating the delivery cost of a software product, when warranty is to be provided, with an imperfect debugging phenomenon. Unlike existing cost models, here the strategy was to consider maintenance support given to the customer with an imperfect debugging phenomenon. The optimal release time can be calculated for various reliability levels by minimizing the cost. The delivery cost, reliability of the software …

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A Sensitive Ann Based Differential Relay For Transformer Protection With Security Against Ct Saturation And Tap Changer Operation, Hassan Khorashadi Zadeh, Zuyi Li Jan 2007

A Sensitive Ann Based Differential Relay For Transformer Protection With Security Against Ct Saturation And Tap Changer Operation, Hassan Khorashadi Zadeh, Zuyi Li

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents an artificial neural network (ANN) based scheme for fault identification in power transformer protection. The proposed scheme is featured by the application of ANN to identifying system patterns, the unique choice of harmonics of positive sequence differential currents as ANN inputs, the effective handling of current transformer (CT) saturation with an ANN based approach, and the consideration of tap changer position for correcting secondary CT current. Performance of the proposed scheme is studied for a wide variety of operating conditions using data generated from simulation. The results indicate that the proposed scheme provides a fast and sensitive …

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An Architecture For Embedded System Communication, Chakradhar Medavarapu Jan 2007

An Architecture For Embedded System Communication, Chakradhar Medavarapu

LSU Master's Theses

Time is a major constraint in the development of most embedded systems. In many cases, the development of embedded software is directly dependent on the development of the embedded systems. This calls for a development framework that enables embedded software and hardware to be developed in parallel. In an attempt to solve the problem, a concept prototype hardware-in-the-loop (HIL) simulation methodology has been proposed and implemented at the Ohio State University for the TMS320LF2407A DSP board. We build on top of that HIL system by rewriting the low level device drivers that allow data and control information to be set …

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Introduction: Special Issue For The Selected Papers In The Fourth International Conference On Intelligent Multimedia Computing And Networking (Immcn) 2005, Chong-Wah Ngo, Hong-Va Leong Jan 2007

Introduction: Special Issue For The Selected Papers In The Fourth International Conference On Intelligent Multimedia Computing And Networking (Immcn) 2005, Chong-Wah Ngo, Hong-Va Leong

Research Collection School Of Computing and Information Systems

This special issue introduces seven papers selected from the IMMCN’ 2005, covering a wide range of emerging topics in multimedia field. These papers receive high scores and good comments from the reviewers in their respective areas of intelligent and nextgeneration networking, technology and application, multimedia coding, content analysis and retrieval. The seven papers are extended to 20 pages and then gone through another review process before the final publication. In this issue, we have two papers for video streaming, two papers for multimedia applications, one paper for video coding, and two papers for image and video retrieval.

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Analogical Modeling: An Update, Deryle W. Lonsdale, David Eddington Jan 2007

Analogical Modeling: An Update, Deryle W. Lonsdale, David Eddington

Faculty Publications

Analogical modeling is a supervised exemplar-based approach that has been widely applied to predict linguistic behavior. The paradigm has been well documented in the linguistics and cognition literature, but is less well known to the machine learning community. This paper sets out some of the basics of the approach, including a simplified example of the fundamental algorithm’s operation. It then surveys some of the recent analogical modeling language applications, and sketches how the computational system has been enhanced lately to offer users increased flexibility and processing power. Some comparisons and contrasts are drawn between analogical modeling and other language modeling …

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National Culture And Its Effects On Knowledge Communication In Online Virtual Communities, Keng Siau, Fiona Fui-Hoon Nah, Min Ling Jan 2007

National Culture And Its Effects On Knowledge Communication In Online Virtual Communities, Keng Siau, Fiona Fui-Hoon Nah, Min Ling

Research Collection School Of Computing and Information Systems

Online virtual communities provide a powerful means of knowledge sharing. Despite the prevalence of online virtual communities, there is a paucity of research to investigate the effect of national culture differences on knowledge sharing in online virtual communities. Are there differences between online virtual communities from different national cultures? This research studies the differences in knowledge-sharing activities between US-based and China-based online virtual communities. Hofstede's dimensions of national culture serve as the theoretical foundation for this research.

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A Growth Theory Perspective On The International Diffusion Of Electronic Commerce., S.C Ho, Robert John Kauffman, T.P. Liang Jan 2007

A Growth Theory Perspective On The International Diffusion Of Electronic Commerce., S.C Ho, Robert John Kauffman, T.P. Liang

Research Collection School Of Computing and Information Systems

Information and communication technologies (ICTs) continue to have a profound effect on the economies and societies where they are used. In this article, we propose three related theories to describe the underlying mechanism for growth in e-commerce revenues at the national level. Endogenous growth theory posits that the primary drivers of e-commerce growth are internal to a country. Exogenous growth theory suggests that the primary drivers of e-commerce growth are external to an economic system, and reflect the forces of the regional economy. A blend of these, a mixed endogenous–exogenous growth theory, incorporates drivers from both the economy and …

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An Improvement Heuristic For The Timetabling Problem, Aldy Gunawan, Kien Ming Ng, Kim Leng Poh Jan 2007

An Improvement Heuristic For The Timetabling Problem, Aldy Gunawan, Kien Ming Ng, Kim Leng Poh

Research Collection School Of Computing and Information Systems

This paper formulates a timetabling problem, which is often encountered in a university, as a mathematical programming model. The proposed model combines both teacher assignment and course scheduling problems simultaneously, which causes the entire model to become more complex. We propose an improvement heuristic algorithm to solve such a model. The proposed algorithm has been tested with several randomly generated datasets of sizes that are comparable to those occurring in a university in Indonesia. The computational results show that the improvement heuristic is not only able to obtain good solutions, but is also able to do so within reasonable computational …

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Pi-Calculus In Logical Form, Marcello M. Bonsangue, Alexander Kurz Jan 2007

Pi-Calculus In Logical Form, Marcello M. Bonsangue, Alexander Kurz

Engineering Faculty Articles and Research

Abramsky’s logical formulation of domain theory is extended to encompass the domain theoretic model for picalculus processes of Stark and of Fiore, Moggi and Sangiorgi. This is done by defining a logical counterpart of categorical constructions including dynamic name allocation and name exponentiation, and showing that they are dual to standard constructs in functor categories. We show that initial algebras of functors defined in terms of these constructs give rise to a logic that is sound, complete, and characterises bisimilarity. The approach is modular, and we apply it to derive a logical formulation of pi-calculus. The resulting logic is a …

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Application-Specific Reliable Data Transfer In Wireless Sensor Networks, Damayanti Datta Jan 2007

Application-Specific Reliable Data Transfer In Wireless Sensor Networks, Damayanti Datta

LSU Doctoral Dissertations

A wireless sensor network (WSN) is a collection of sensor nodes and base stations connected via wireless medium. It sends data collected from the nodes to the base stations for generating information. The size and low cost of the sensor nodes as well as the WSN's ability to connect without wired links are its key advantages which enable it to be deployed in hostile or inaccessible environments at low cost. However, WSNs suffer from high data loss due to the inherent weaknesses in a wireless transmission medium, transmission problems in hostile environments due to human interference, etc. and node failures …

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Firearm Identification With Hierarchical Neural Networks By Analyzing The Firing Pin Images Retrieved From Cartridge Cases, Dongguang Li Jan 2007

Firearm Identification With Hierarchical Neural Networks By Analyzing The Firing Pin Images Retrieved From Cartridge Cases, Dongguang Li

Research outputs pre 2011

When a gun is fired, characteristic markings on the cartridge and projectile of a bullet are produced. Over thirty different features can be distinguished from observing these marks, which in combination produce a "fingerprint" for identification of a firearm. ln this paper, through the use of hierarchial neural networks a firearm identification system based on cartridge case images is proposed. We focus on the cartridge case identification of rim-fire mechanism. Experiments show that the model proposed has high performance and robustness by integrating two levels Self- Organizing Feature Map (SOFM) neural networks and the decision-making strategy. This model will also …

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Australian Firearm Identification System Based On The Ballistics Images Of Projectile Specimens, Dongguang Li Jan 2007

Australian Firearm Identification System Based On The Ballistics Images Of Projectile Specimens, Dongguang Li

Research outputs pre 2011

Charactetistic markings on the cartridge case and projectile of a fired bullet are created when it is fired. Over thirty different features within these marks can be distinguished, which in combination produce a "fingerprint" for a firearm. By analyzing features within such a set of fireann :fingerprints, it will be possible to identify not only the type and model of a fireann, but also each every individual weapon as effectively as human :fingerprint identification. A new analytic system based on fast Fourier transform (FFT) for identifying the projectile specimens by the line-scan imaging technique is proposed in this paper. Experimental …

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Proceedings Of The Sixth International Workshop For Applied Pkc (Iwap2007), Dongguang Li Jan 2007

Proceedings Of The Sixth International Workshop For Applied Pkc (Iwap2007), Dongguang Li

Research outputs pre 2011

IWAP2007 will be the sixth of a series of successful international workshops with focus on research and engineering issues of the applied aspects of public key cryptosystems. The inaugural IWAP event was held in Korea in 2001, and was subsequently held in 2002, 2004, 2005 and 2006 respectively in Taipei, Japan, Singapore and China. The IWAP2003 was cancelled due to the SARS breakout. Theoreticians and practitioners interested in the applied issues of PKC were encouraged to participate and contribute to the continuous success of the IWAP workshop series. The host of the IWAP2007 is Edith Cowan University. It is my …

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Analysis Of Pki As A Means Of Securing Odf Documents, Gautham Kasinath, Leisa J. Armstrong Jan 2007

Analysis Of Pki As A Means Of Securing Odf Documents, Gautham Kasinath, Leisa J. Armstrong

Research outputs pre 2011

Public Key Infrastructure (PKI) has for the last two decades been a means of securing systems and communication. With the adoption of Open Document Format (ODF) as an ISO standard, the question remains if the unpopular, expensive, complex and unmaintainable PKI can prove to be a viable means of securing ODF documents. This paper analyses the drawbacks of PKI and evaluates the useji.tlness of PKl in provisioning robust, cheap and maintainable XML security to XML based ODF. This paper also evaluates the existing research on XML security, more specifically fine grained access control.

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