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1
Makin, Cameron. „Primary User Obfuscation in an Incumbent Informed Spectrum Access System“. Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104015.
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With a growing demand for spectrum availability, spectrum sharing has become a high-profile solution to overcrowding. In order to enable spectrum sharing between incumbent/primary and secondary users, incumbents must have spectrum protection and privacy from malicious new entrants. In this Spectrum Access System (SAS) advancement, Primary Users (PUs) are obfuscated with the efforts of the SAS and the cooperation of obedient new entrants. Further, the necessary changes to the SAS to support this privacy scheme are exposed to suggest improvements in PU privacy, Citizens Broadband Radio Service Device (CBSD)-SAS relations, and punishment for unauthorized transmission. Results show the feasibility for PU obfuscation with respect to malicious spectrum sensing users. Simulation results indicate that the obfuscation scheme can deliver location and frequency occupation privacy with 75% and 66% effectiveness respectively in a 100% efficient spectrum utilization oriented obfuscation scheme. A scheme without spectrum utilization constraint shows up to 91% location privacy effectiveness. Experiment trials indicate that the privacy tactic can be implemented on an open-source SAS, however environmental factors may degrade the tactic's performance.Master of Science
With a growing demand for spectrum availability, wireless spectrum sharing has become a high-profile solution to spectrum overcrowding. In order to enable spectrum sharing between incumbent/primary (e.g.,federal communications, naval radar, users already grandfathered into the band) and secondary users (e.g., commercial communications companies), incumbents must have spectrum protection and privacy from malicious new entrants. In this Spectrum Access System (SAS) advancement, Primary Users (PUs) are obfuscated with the efforts of the incumbent informed SAS and the cooperation of obedient new entrants. Further, the necessary changes to the SAS to support this privacy scheme are exposed to suggest improvements in PU privacy, Citizens Broadband Radio Service Device (CBSD)-SAS relations, and punishment for unauthorized transmission. Results show the feasibility of PU obfuscation with respect to malicious spectrum sensing users. Simulation results indicate that the obfuscation tactic can deliver location and frequency occupation privacy with 75% and 66% effectiveness respectively in a 100% efficient spectrum utilization oriented obfuscation scheme. A scheme without spectrum utilization constraint shows up to 91% location privacy effectiveness. Experiment trials indicate that the privacy tactic can be implemented on an open-source SAS, however environmental factors may degrade the tactic's performance.
2
Dou, Yanzhi. „Toward Privacy-Preserving and Secure Dynamic Spectrum Access“. Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/81882.
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Dynamic spectrum access (DSA) technique has been widely accepted as a crucial solution to
mitigate the potential spectrum scarcity problem. Spectrum sharing between the government
incumbents and commercial wireless broadband operators/users is one of the key forms of
DSA. Two categories of spectrum management methods for shared use between incumbent
users (IUs) and secondary users (SUs) have been proposed, i.e., the server-driven method and
the sensing-based method. The server-driven method employs a central server to allocate
spectrum resources while considering incumbent protection. The central server has access to
the detailed IU operating information, and based on some accurate radio propagation model,
it is able to allocate spectrum following a particular access enforcement method. Two types
of access enforcement methods -- exclusion zone and protection zone -- have been adopted for
server-driven DSA systems in the current literature. The sensing-based method is based on
recent advances in cognitive radio (CR) technology. A CR can dynamically identify white
spaces through various incumbent detection techniques and reconfigure its radio parameters
in response to changes of spectrum availability. The focus of this dissertation is to address
critical privacy and security issues in the existing DSA systems that may severely hinder the
progress of DSA's deployment in the real world.
Firstly, we identify serious threats to users' privacy in existing server-driven DSA designs and
propose a privacy-preserving design named P2-SAS to address the issue. P2-SAS realizes the
complex spectrum allocation process of protection-zone-based DSA in a privacy-preserving
way through Homomorphic Encryption (HE), so that none of the IU or SU operation data
would be exposed to any snooping party, including the central server itself.
Secondly, we develop a privacy-preserving design named IP-SAS for the exclusion-zone-
based server-driven DSA system. We extend the basic design that only considers semi-
honest adversaries to include malicious adversaries in order to defend the more practical and
complex attack scenarios that can happen in the real world.
Thirdly, we redesign our privacy-preserving SAS systems entirely to remove the somewhat-
trusted third party (TTP) named Key Distributor, which in essence provides a weak proxy
re-encryption online service in P2-SAS and IP-SAS. Instead, in this new system, RE-SAS,
we leverage a new crypto system that supports both a strong proxy re-encryption notion
and MPC to realize privacy-preserving spectrum allocation. The advantages of RE-SAS are
that it can prevent single point of vulnerability due to TTP and also increase SAS's service
performance dramatically.
Finally, we identify the potentially crucial threat of compromised CR devices to the ambient
wireless infrastructures and propose a scalable and accurate zero-day malware detection
system called GuardCR to enhance CR network security at the device level. GuardCR
leverages a host-based anomaly detection technique driven by machine learning, which makes
it autonomous in malicious behavior recognition. We boost the performance of GuardCR in
terms of accuracy and efficiency by integrating proper domain knowledge of CR software.Ph. D.
3
Lu, Chang. „Inclusion of Priority Access in a Privacy-preserving ESC-based DSA System“. Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/84872.
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According to the Federal Communications Commission's rules and recommendations set forth for the 3.5 GHz Citizens Broadband Radio Service, a three-tiered structure shall govern the newly established shared wireless band. The three tiers are comprised of three different levels of spectrum access; Incumbent Access, Priority Access and General Authorized Access. In accordance and fulfillment with this dynamic spectrum access framework, we present the inclusion of Priority Access tier into a two-tiered privacy-preserving ESC-based dynamic spectrum access system.Master of Science
4
Zabransky, Douglas Milton. „Incorporating Obfuscation Techniques in Privacy Preserving Database-Driven Dynamic Spectrum Access Systems“. Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85001.
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Modern innovation is a driving force behind increased spectrum crowding. Several studies performed by the National Telecommunications and Information Administration (NTIA), Federal Communications Commission (FCC), and other groups have proposed Dynamic Spectrum Access (DSA) as a promising solution to alleviate spectrum crowding. The spectrum assignment decisions in DSA will be made by a centralized entity referred to as as spectrum access system (SAS); however, maintaining spectrum utilization information in SAS presents privacy risks, as sensitive Incumbent User (IU) operation parameters are required to be stored by SAS in order to perform spectrum assignments properly. These sensitive operation parameters may potentially be compromised if SAS is the target of a cyber attack or an inference attack executed by a secondary user (SU).
In this thesis, we explore the operational security of IUs in SAS-based DSA systems and propose a novel privacy-preserving SAS-based DSA framework, Suspicion Zone SAS (SZ-SAS), the first such framework which protects against both the scenario of inference attacks in an area with sparsely distributed IUs and the scenario of untrusted or compromised SAS. We then define modifications to the SU inference attack algorithm, which demonstrate the necessity of applying obfuscation to SU query responses. Finally, we evaluate obfuscation schemes which are compatible with SZ-SAS, verifying the effectiveness of such schemes in preventing an SU inference attack. Our results show SZ-SAS is capable of utilizing compatible obfuscation schemes to prevent the SU inference attack, while operating using only homomorphically encrypted IU operation parameters.Master of Science
5
Lin, Yousi. „Spectrum Management Issues in Centralized and Distributed Dynamic Spectrum Access“. Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104362.
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Dynamic spectrum access (DSA) is a powerful approach to mitigate the spectrum scarcity problem caused by rapid increase in wireless communication demands. Based on architecture design, DSA systems can be categorized as centralized and distributed. To successfully enable DSA, both centralized and distributed systems have to deal with spectrum management issues including spectrum sensing, spectrum decision, spectrum sharing and spectrum mobility. Our work starts by investigating the challenges of efficient spectrum monitoring in centralized spectrum sensing. Since central controllers usually require the presence information of incumbent users/primary users (IUs) for decision making, which is obtained during spectrum sensing, privacy issues of IUs become big concerns in some DSA systems where IUs have strong operation security needs. To aid in this, we design novel location privacy protection schemes for IUs. Considering the general drawbacks of centralized systems including high computational overhead for central controllers, single point failure and IU privacy issues, in many scenarios, a distributed DSA system is required. In this dissertation, we also cope with the spectrum sharing issues in distributed spectrum management, specifically the secondary user (SU) power control problem, by developing distributed and secure transmit power control algorithms for SUs.
In centralized spectrum management, the common approach for spectrum monitoring is to build infrastructures (e.g. spectrum observatories), which cost much money and manpower yet have relatively low coverage. To aid in this, we propose a crowdsourcing based spectrum monitoring system to capture the accurate spectrum utilization at a large geographical area, which leverages the power of masses of portable mobile devices. The central controller can accurately predict future spectrum utilization and intelligently schedule the spectrum monitoring tasks among mobile SUs accordingly, so that the energy of mobile devices can be saved and more spectrum activities can be monitored. We also demonstrate our system's ability to capture not only the existing spectrum access patterns but also the unknown patterns where no historical spectrum information exists. The experiment shows that our spectrum monitoring system can obtain a high spectrum monitoring coverage with low energy consumption.
Environmental Sensing Capability (ESC) systems are utilized in DSA in 3.5 GHz to sense the IU activities for protecting them from SUs' interference. However, IU location information is often highly sensitive in this band and hence it is preferable to hide its true location under the detection of ESCs. As a remedy, we design novel schemes to preserve both static and moving IU's location information by adjusting IU's radiation pattern and transmit power. We first formulate IU privacy protection problems for static IU. Due to the intractable nature of this problem, we propose a heuristic approach based on sampling. We also formulate the privacy protection problem for moving IUs, in which two cases are analyzed: (1) protect IU's moving traces; (2) protect its real-time current location information. Our analysis provides insightful advice for IU to preserve its location privacy against ESCs. Simulation results show that our approach provides great protection for IU's location privacy.
Centralized DSA spectrum management systems has to bear several fundamental issues, such as the heavy computational overhead for central controllers, single point failure and privacy concerns of IU caused by large amounts of information exchange between users and controllers and often untrusted operators of the central controllers. In this dissertation, we propose an alternative distributed and privacy-preserving spectrum sharing design for DSA, which relies on distributed SU power control and security mechanisms to overcome the limitations of centralized DSA spectrum management.Doctor of Philosophy
Due to the rapid growth in wireless communication demands, the frequency spectrum is becoming increasingly crowded. Traditional spectrum allocation policy gives the unshared access of fixed bands to the licensed users, and there is little unlicensed spectrum left now to allocate to newly emerged communication demands. However, studies on spectrum occupancy show that many licensed users who own the license of certain bands are only active for a small percentage of time, which results in plenty of underutilized spectrum. Hence, a new spectrum sharing paradigm, called dynamic spectrum access (DSA), is proposed to mitigate this problem. DSA enables the spectrum sharing between different classes of users, generally, the unlicensed users in the DSA system can access the licensed spectrum opportunistically without interfering with the licensed users. Based on architecture design, DSA systems can be categorized as centralized and distributed. In centralized systems, a central controller will make decisions on spectrum usage for all unlicensed users. Whereas in distributed systems, unlicensed users can make decisions for themselves independently. To successfully enable DSA, both centralized and distributed DSA systems need to deal with spectrum management issues, such as resource allocation problems and user privacy issues, etc. The resource allocation problems include, for example, the problems to discover and allocate idle bands and the problems to control users' transmit power for successful coexistence. Privacy issues may also arise during the spectrum management process since certain information exchange is inevitable for global decision making. However, due to the Federal Communications Commission's (FCC) regulation, licensed users' privacy such as their location information must be protected in any case. As a result, dynamic and efficient spectrum management techniques are necessary for DSA users. In this dissertation, we investigate the above-mentioned spectrum management issues in both types of DSA systems, specifically, the spectrum sensing challenges with licensed user location privacy issues in centralized DSA, and the spectrum sharing problems in distributed DSA systems. In doing so, we propose novel schemes for solving each related spectrum management problem and demonstrate their efficacy through the results from extensive evaluations and simulations. We believe that this dissertation provides insightful advice for DSA users to solve different spectrum management issues for enabling DSA implementation, and hence helps in a wider adoption of dynamic spectrum sharing.
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Bhadriraju, Abhay Rao. „Misuse Detection in Dynamic Spectrum Access Networks“. Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/49259.
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With dynamic spectrum access emerging as an important paradigm for efficient spectrum use, mechanisms are required to ensure disciplined spectrum access by secondary users. This must be done without requiring secondary users to disclose private data, such as their exact usage pattern or identities of parties involved. We formulate, design and evaluate a mechanism to collect spectrum activity information using a set of CPEs. A system design is presented which uses a number of techniques to address mobility and security issues involved in relying on CPEs to collect spectrum activity information. The system imposes an observation probability such that a rational cheater is dissuaded from spectrum misuse. The minimum number of CPEs required to impose this observation probability is determined by formulating it as an integer linear program. The security and privacy of this system is analyzed, along with simulation results to evaluate the quality of the solution. Based on the current design, directions for future work are identified and preliminary approaches are presented.Master of Science
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Ullah, Abid. „Mechanisms for Enhancing Spectrum Utilization in a Spectrum Access System“. Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/84932.
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The goal of this thesis is to build a Protected Shared Access Model (PSAM) through database enabled Spectrum Access System (SAS). A model for the SAS is proposed, which is based on our vision for the SAS as a more dynamic and responsive architecture as a geolocation database than the current TVWS database. Major functions and capabilities of the model include, calculations of exclusion zone (EZ) of primary users with different operational parameters, use interference estimation techniques for predicting interference levels
that will be generated by the new secondary users (SUs) and existing systems operating in the database service area, allocate location based transmit power levels and provide an algorithm for communications among the PUs, SUs, and the SAS to implement management and authorization framework of spectrum resources to different types of SUs.
The selection of a propagation model is of utmost importance in spectrum sharing studies. Existing literature on EZs with simplified propagation models does not consider the effect of LOS interference between the PU to SU link and SU to PU link on peak points in the terrain area around the PU. The use of a terrain profile based model captures the essence of propagation over irregular terrain. Terrain regions that are far away from the PU may have a LOS between the PU and SU. So its not only the nearest area where the PU/SU can get interference, but interference is present from areas further away on high grounds having a direct LOS with the PU antenna. The exclusion zone computation with terrain profile based propagation model captures this effect, and it is the same effect that makes the shape of the exclusion zone irregular. So the propagation model used in spectrum sharing studies must be able to use the terrain for the specific geographical area for precise propagation calculations, and provide statistical reliability parameters for the computed propagation values for area of interest.
For a multi-tier shared access model with incumbent access (IA) users, priority access (PA) users and general authorized access (GAA) users. The SU interference tolerance thresholds varies by the type of SU's i-e., PA users like public safety systems and mission critical users have low tolerance for interference and hence need to operate further from the PU. While GAA users like commercial broadband systems have higher interference tolerances and can operate closer to the PU. This multi-tier shared access model requires varying levels of interference protection from PU, that can be provided with multiple exclusion zones defined for different types of SU's.
We propose the concept of differential spectrum access hierarchy, and define it in the context of a multi-tiered EZs that are based on quantiles of tolerable interference levels for different tiers of SUs. We also quantify and show the gain in SU capacity (or throughput) obtained by using multi-tiered EZs for different tiers of SUs. Using simulation results, we show that the size of EZs can be significantly reduced with the use of a terrain profile-based propagation model that takes into account terrain profile for signal attenuation between PUs and SUs in the P2P link.
The exclusion zones involve the use of interference test points at the circumference of the protection contour of the PU. They are monitoring test points that the SAS uses with a propagation model and locations of SUs to calculate interference. Consider a model of Figure 5.1, the coexistence environment with PU, SU and the SAS with a database. As more SUs enter the system, their transmit powers creates interference for the PUs. In the event of SU interference exceeding a predefined threshold level at any of the test points, the SAS uses an interference based power control algorithm to turnoff the nearest dominant interferer's. Turning off the dominant interferers eliminates interference generated by that node at the PU. This nearest node interference cancellation significantly reduces the outage probability at the PU.
Unlike existing metrics for spectrum utilization efficiency that considers separate metrics for PU interference protection and maximum use of the band for secondary use, we define a new metric for spectrum utilization efficiency. This metric uses utility functions and cost functions to measure the impact of secondary use of the spectrum on PUs as well as the degree of satisfaction SUs can achieve from reuse of such spectrum. The new spectrum utilization metric is used to evaluate tradeoffs between interference protection of PUs and SU spectrum utilization.Ph. D.
8
Ye, Yuxian. „Study of Sensing Issues in Dynamic Spectrum Access“. Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90184.
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Dynamic Spectrum Access (DSA) is now a commonly used spectrum sharing paradigm to mitigate the spectrum shortage problem. DSA technology allows unlicensed secondary users to access the unused frequency bands without interfering with the incumbent users. The key technical challenges in DSA systems lie in spectrum allocation problems and spectrum user's security issues. This thesis mainly focuses on spectrum monitoring technology in spectrum allocation and incumbent users' (IU) privacy issue.
Spectrum monitoring is a powerful tool in DSA to help commercial users to access the unused bands. We proposed a crowdsourcing-based unknown IU pattern monitoring scheme that leverages the power of masses of portable mobile devices to reduce the cost of the spectrum monitoring and demonstrate the ability of our system to capture not only the existing spectrum access patterns but also the unknown patterns where no historical spectrum information exist. Due to the energy limit of the battery-based system, we then leverage solar energy harvesting and develop an energy management scheme to support our spectrum monitoring system. We also provide best privacy-protection strategies for both static and mobile IUs in terms of hiding their true location under the detection of Environmental Sensing Capabilities system. In this thesis, the heuristic approach for our mathematical formulations and simulation results are described in detail. The simulation results show our spectrum monitoring system can obtain a high spectrum monitoring coverage and low energy consumption. Our IU privacy scheme provides great protection for IU's location privacy.Master of Science
Spectrum relates to the radio frequencies allocated to the federal users and commercial users for communication over the airwaves. It is a sovereign asset that is overseen by the government in each country to manage the radio spectrum and issue spectrum licenses. In addition, spectrum bands are utilized for various purposes because different bands have different characteristics. However, the overly crowded US frequency allocation chart shows the scarcity of usable radio frequencies. The actual spectrum usage measurements reflect that multiple prized spectrum bands lay idle at most time and location, which indicates that the spectrum shortage is caused by the spectrum management policies rather than the physical scarcity of available frequencies. Dynamic spectrum access (DSA) was proposed as a new paradigm of spectrum sharing that allows commercial users to access the abundant white spaces in the licensed spectrum bands to mitigate the spectrum shortage problem and increase spectrum utilization. In DSA, two of the key technical challenges lie in how to dynamically allocate the spectrum and how to protect spectrum users’ security. This thesis focuses on the development of two types of mechanisms for addressing the above two challenges: (1) developing efficient spectrum monitoring schemes to help secondary users (SU) to accurately and dynamically access the white space in spectrum allocation and (2) developing privacy preservation schemes for incumbent users (IU) to protect their location privacy. Specifically, we proposed an unknown IU pattern monitoring scheme that leverages the power of masses of portable mobile devices to reduce the cost of common spectrum monitoring systems. We demonstrate that our system can track not only the existing IU spectrum access patterns but also the unknown patterns where no historical spectrum information exists. We then leverage the solar energy harvesting and design energy management scheme to support our spectrum monitoring system. Finally, we provide a strategy for both static and mobile IUs to hide their true location under the monitoring of Environmental Sensing Capabilities systems.
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Bahrak, Behnam. „Ex Ante Approaches for Security, Privacy, and Enforcement in Spectrum Sharing“. Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/24720.
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Cognitive radios (CRs) are devices that are capable of sensing the spectrum and using its free portions in an opportunistic manner. The free spectrum portions are referred to as white spaces or spectrum holes. It is widely believed that CRs are one of the key enabling technologies for realizing a new regulatory spectrum management paradigm, viz. dynamic spectrum access (DSA). CRs often employ software-defined radio (SDR) platforms that are capable of executing artificial intelligence (AI) algorithms to reconfigure their transmission/reception (TX/RX) parameters to communicate efficiently while avoiding interference with licensed (a.k.a. primary or incumbent) users and unlicensed (a.k.a. secondary or cognitive) users.
When different stakeholders share a common resource, such as the case in spectrum sharing, security, privacy, and enforcement become critical considerations that affect the welfare of all stakeholders. Recent advances in radio spectrum access technologies, such as CRs, have made spectrum sharing a viable option for significantly improving spectrum utilization efficiency. However, those technologies have also contributed to exacerbating the difficult problems of security, privacy and enforcement. In this dissertation, we review some of the critical security and privacy threats that impact spectrum sharing. We also discuss ex ante (preventive) approaches which mitigate the security and privacy threats and help spectrum enforcement.Ph. D.
10
Maggenti, Mark A. „Spread spectrum satellite multiple access and overlay service“. Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45769.
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This thesis presents two applications of spread spectrum technology to very small aperture terminal (VSAT) satellite communication networks. It describes two spread spectrum multiple access systems which use a form of noncoherent M-ary FSK (MFSK) as the primary modulation and analyzes their throughput. The analysis considers such factors as satellite power constraints and adjacent satellite interference. It considers the effect of onâ board processing on the multiple access efficiency and investigates the feasibility of overlaying low data rate spread spectrum signals on existing satellite traffic as a form of frequency reuse.
Master of Science
11
Kikamaze, Shem. „Design, Deployment and Performance of an Open Source Spectrum Access System“. Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85629.
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Spectrum sharing is possible, but lacks R & D support for practical solutions that satisfy both the incumbent and secondary or opportunistic users. The author found a lack of an openly available framework supporting experimental research on the performance of a Spectrum Access System (SAS) and propose to build an open-source Software Defined Radio (SDR) based framework. This framework will test different dynamic spectrum scenarios in a wireless testbed. This thesis presents our Spectrum Access System prototype, discusses the design choices and trade-offs and provides a proof of concept implementation. We show that an Internet-accessible CORNET test bed provides the ideal platform for developing and testing the SAS functionality and its building blocks and offerss the hardware and software as a community resource for research and education. This design provides the necessary interfaces for researchers to develop and test their SAS-related modules, waveforms and scenarios.Master of Science
In this information age, the number of wireless devices is growing faster than the infrastructure required to make wireless communication possible. This creates a possibility of not having enough radio spectrum to keep up with this growing demand. To alleviate this issue, there is a need to research and find more ways of efficiently utilizing the current spectrum resources available. Dynamic spectrum allocation is one way forward to archiving this goal. Frequency channels are assigned to devices based on prevailing conditions like device location and availability of channels that would cause low interference to other devices. Spectrum utilization is based on time, frequency and space with devices having the ability to hop to the best channel available. In this thesis, an open-source Spectrum Access System (SAS) was created as a platform through which dynamic spectrum allocation research can be done. The SAS is centralized management system that logs information about the prevailing spectrum usage, and in turn uses this information to dynamically allocate spectrum to devices and networks. This thesis shows how it was implemented, its current performance, and the steps that different researchers can take to add their own functionalities.
12
ZHENG, YAO. „Privacy-Preserving Personal Health Record System Using Attribute-Based Encryption“. Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/902.
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"Personal health record (PHR) service is an emerging model for health information exchange. It allows patients to create, manage, control and share their health information with other users as well as healthcare providers. In reality, a PHR service is likely to be hosted by third-party cloud service providers in order to enhance its interoperability. However, there have been serious privacy concerns about outsourcing PHR data to cloud servers, not only because cloud providers are generally not covered entities under HIPAA, but also due to an increasing number of cloud data breach incidents happened in recent years. In this thesis, we propose a privacy-preserving PHR system using attribute-based encryption (ABE). In this system, patients can encrypt their PHRs and store them on semi-trusted cloud servers such that servers do not have access to sensitive PHR contexts. Meanwhile patients maintain full control over access to their PHR files, by assigning fine-grained, attribute-based access privileges to selected data users, while different users can have access to different parts of their PHR. Our system also provides extra features such as populating PHR from professional electronic health record (EHR) using ABE. In order to evaluate our proposal, we create a Linux library that implement primitive of key-policy attribute-based encryption (KP-ABE) algorithms. We also build a PHR application based on Indivo PCHR system that allow doctors to encrypt and submit their prescription and diagnostic note to PHR servers using KP-ABE. We evaluate the performance efficiency of different ABE schemes as well as the data query time of Indivo PCHR system when PHR data are encrypted under ABE scheme."
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Ramanujachari, Divya. „Using Incumbent Channel Occupancy Prediction to Minimize Secondary License Grant Revocations“. Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/86384.
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With commercial deployment of the Citizens Band Radio Service commencing in the last
quarter of 2018, efforts are in progress to improve the efficiency of the Spectrum Access
System (SAS) functions. An area of concern as identified in recent field trials is the timebound
evacuation of unlicensed secondary users from a frequency band by the SAS on
the arrival of an incumbent user. In this thesis, we propose a way to optimize the evacuation
process by reducing the number of secondary spectrum grant revocations to be
performed. The proposed work leverages knowledge of incumbent user spectrum occupancy
pattern obtained from historical spectrum usage data. Using an example model
trained on 48 hours of an incumbent user transmission information, we demonstrate prediction
of future incumbent user spectrum occupancy for the next 15 hours with 94.4%
accuracy. The SAS uses this information to set the time validity of the secondary spectrum
grants appropriately. In comparison to a case where spectrum grants are issued with no
prior knowledge, the number of revocations declines by 87.5% with a 7.6% reduction in
channel utilization. Further, the proposed technique provides a way for the SAS to plan
ahead and prepare a backup channel to which secondary users can be redirected which
can reduce the evacuation time significantly.Master of Science
Studies on spectrum occupancy show that, in certain bands, licensed incumbent users use the spectrum only for some time or only within certain geographical limits. The dynamic spectrum access paradigm proposes to reclaim the underutilized spectrum by allowing unlicensed secondary users to access the spectrum opportunistically in the absence of the licensed users. In the United States, the Federal Communications Commission (FCC) has identified 150 MHz of spectrum space from 3550-3700 MHz to implement a dynamic spectrum sharing service called the Citizens Broadband Radio Service (CBRS). The guiding principle of this service is to maximize secondary user channel utilization while ensuring minimal incumbent user disruption. In this study, we propose that these conflicting requirements can be best balanced in the Spectrum Access System (SAS) by programming it to set the time validity of the secondary license grants by taking into consideration the incumbent spectrum occupancy pattern. In order to enable the SAS to learn incumbent spectrum occupancy in a privacy-preserving manner, we propose the use of a deep learning model, specifically the long-short term memory (LSTM). This model can be trained by federal agencies on historical incumbent spectrum occupancy information and then shared with the SAS in a secure manner to obtain prediction information about possible incumbent activity. Then, using the incumbent spectrum occupancy information from the LSTM model, the SAS could issue license grants that would expire before expected arrival time of incumbent user, thus minimizing the number of revocations on incumbent arrival. The scheme was validated using simulations that demonstrated the effectiveness of this approach in minimizing revocation complexity.
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Sohul, Munawwar Mahmud. „Spectrum Opportunity Duration Assurance: A Primary-Secondary Cooperation Approach for Spectrum Sharing Systems“. Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/88018.
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The radio spectrum dependent applications are facing a huge scarcity of the resource. To address this issue, future wireless systems require new wireless network architectures and new approaches to spectrum management. Spectrum sharing has emerged as a promising solution to address the radio frequency (RF) spectrum bottleneck. Although spectrum sharing is intended to provide flexible use of the spectrum, the architecture of the existing approaches, such as TV White Space [1] and Citizen Broadband Radio Services (CBRS) [2], have a relatively fixed sharing framework. This fixed structure limits the applicability of the architecture to other bands where the relationship between various new users and different types of legacy users co-exist. Specifically, an important aspect of sharing that has not been explored enough is the cooperation between the resource owner and the opportunistic user. Also in a shared spectrum system, the users do not have any information about the availability and duration of the available spectrum opportunities. This lack of understanding about the shared spectrum leads the research community to explore a number of core spectrum sharing tasks, such as opportunity detection, dynamic opportunity scheduling, and interference protection for the primary users, etc. This report proposes a Primary-Secondary Cooperation Framework to provide flexibility to all the involved parties in terms of choosing the level of cooperation that allow them to satisfy different objective priorities. The cooperation framework allows exchange of a probabilistic assurance: Spectrum Opportunity Duration Assurance (SODA) between the primary and secondary operations to improve the overall spectrum sharing experience for both the parties. This capability will give the spectrum sharing architectures new flexibility to handle evolutions in technologies, regulations, and the requirements of new bands being transitioned from fixed to share usage.
In this dissertation we first look into the regulatory aspect of spectrum sharing. We analyze the Federal Communications Commission's (FCC) initiatives with regards to the commercial use of the 150 MHz spectrum block in the 3.5 GHz band. This analysis results into a Spectrum Access System (SAS) architecture and list of required functionalities. Then we address the nature of primary-secondary cooperation in spectrum sharing and propose to generate probabilistic assurances for spectrum opportunities. We use the generated assurance to observe the impact of cooperation from the perspective of spectrum sharing system management. We propose to incorporate primary user cooperation in the auctioning and resource allocation procedures to manage spectrum opportunities. We also analyze the improvement in spectrum sharing experience from the perspective of the primary and secondary users as a result of cooperation. We propose interference avoidance schemes that involve cooperation to improve the achievable quality of service.
Primary-secondary cooperation has the potential to significantly influence the mechanism and outcomes of the spectrum sharing systems. Both the primary and secondary operations can benefit from cooperation in a sharing scenario. Based on the priorities of the primary and secondary operations, the users may decide on the level of cooperation that they are willing to participate. Also access to information about the availability and usability of the spectrum opportunity will result in efficient spectrum opportunity management and improved sharing performance for both the primary and secondary users. Thus offering assurances about the availability and duration of spectrum opportunity through primary-secondary cooperation will significantly improve the overall spectrum sharing experience. The research reported in this dissertation is expected to provide a fundamental analytical framework for characterizing and quantifying the implications of primary-secondary cooperation in a spectrum sharing context. It analyzes the technical challenges in modeling different level of cooperation and their impact on the spectrum sharing experience. We hope that this dissertation will establish the fundamentals of the spectrum sharing to allow the involved parties to participate in sharing mechanisms that is suitable to their objective priorities.PHD
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Williams, Jennifer. „Acceptance of a Remote Desktop Access System to Increase Workspace Awareness“. Thesis, University of Waterloo, 2000. http://hdl.handle.net/10012/846.
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Awareness systems are being designed and implemented to improve employee connections. This study examines the variables that affect the acceptance of an awareness system. The awareness system that was used for this research was a remote desktop access system. The independent variables investigated were the degree of detail that can be viewed on a desktop, whether the users can control who can access their desktops, whether the users can control when others have access to their desktops, the equality of access to others' desktops, and task-technology fit. In determining the effect of the independent variables on acceptance, the dependent variable, the mediating variables of privacy and fairness were taken into account. There was a preliminary survey conducted to determine appropriate situations to be used in the scenario descriptions for the survey for the main study. The methodology of policy-capturing surveys was utilized to conduct the survey for the main study in order to investigate the model developed in this study. The policy-capturing survey was pre-tested on University of Waterloo students. The main study was conducted in two different organizations, the subjects for the first study were employees from the Information Systems and Technology Department at the University of Waterloo and the subjects for the second study were employees from Ciber Incorporated. Results indicate that perceptions of privacy and perceptions of fairness have significant effects on acceptance. Also, perceptions of privacy and fairness are related to details in the design of the remote desktop access system. This research may be a contribution to this field since little research has been conducted in this area and implications can be drawn for future research on acceptance of awareness systems.
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Oyediran, David. „Spectrum Sharing: Overview and Challenges of Small Cells Innovation in the Proposed 3.5 GHz Band“. International Foundation for Telemetering, 2015. http://hdl.handle.net/10150/596402.
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ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NVSpectrum sharing between Federal and commercial users is a technique proposed by the FCC and NTIA to open up the 3.5 GHz band for wireless broadband use and small cell technology is one of the candidates for its' realization. The traffic on small cells is temporal and their chances of interfering with other services in shared spectrum are limited. DoD has a documented requirement of 865 MHz by 2025 to support telemetry but only 445 MHz is presently available. DoD is conducting researches to realize test and evaluation spectrum efficient technology with the aim to develop, demonstrate, and evaluate technology components required to enable flight and ground test telemetry operations. This paper will provide an overview on spectrum sharing using small cell technology for LTE-Advanced and dynamic spectrum access would be briefly described. Research challenges for protocols and algorithms would be addressed for future studies.
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Shin, Hong-Sup. „Analysis of the probability of error in frequency hopping multiple access system /“. Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/5868.
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Reuben, Jenni. „Privacy-aware Use of Accountability Evidence“. Licentiate thesis, Karlstads universitet, Institutionen för matematik och datavetenskap (from 2013), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-48550.
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This thesis deals with the evidence that enable accountability, the privacy risks involved in using them and a privacy-aware solution to the problem of unauthorized evidence disclosure. Legal means to protect privacy of an individual is anchored on the data protection perspective i.e., on the responsible collection and use of personal data. Accountability plays a crucial role in such legal privacy frameworks for assuring an individual’s privacy. In the European context, accountability principle is pervasive in the measures that are mandated by the General Data Protection Regulation. In general, these measures are technically achieved through automated privacy audits. System traces that record the system activities are the essential inputs to those automated audits. Nevertheless, the traces that enable accountability are themselves subject to privacy risks, because in most cases, they inform about processing of the personal data. Therefore, ensuring the privacy of the accountability traces is equally important as ensuring the privacy of the personal data. However, by and large, research involving accountability traces is concerned with storage, interoperability and analytics challenges rather than on the privacy implications involved in processing them. This dissertation focuses on both the application of accountability evidence such as in the automated privacy audits and the privacy aware use of them. The overall aim of the thesis is to provide a conceptual understanding of the privacy compliance research domain and to contribute to the solutions that promote privacy-aware use of the traces that enable accountability. To address the first part of the objective, a systematic study of existing body of knowledge on automated privacy compliance is conducted. As a result, the state-of-the-art is conceptualized as taxonomies. The second part of the objective is accomplished through two results; first, a systematic understanding of the privacy challenges involved in processing of the system traces is obtained, second, a model for privacy aware access restrictions are proposed and formalized in order to prevent illegitimate access to the system traces. Access to accountability traces such as provenance are required for automatic fulfillment of accountability obligations, but they themselves contain personally identifiable information, hence in this thesis we provide a solution to prevent unauthorized access to the provenance traces.This thesis deals with the evidence that enables accountability, the privacy risks involved in using it and proposes a privacy-aware solution for preventing unauthorized evidence disclosure. Accountability plays a crucial role in the legal privacy frameworks for assuring individuals’ privacy. In the European context, accountability principle is pervasive in the measures that are mandated by the General Data Protection Regulation. In general, these measures are technically achieved through automated privacy audits. Traces that record the system activities are the essential inputs to those audits. Nevertheless, such traces that enable accountability are themselves subject to privacy risks, because in most cases, they inform about the processing of the personal data. Therefore, ensuring the privacy of the traces is equally important as ensuring the privacy of the personal data. The aim of the thesis is to provide a conceptual understanding of the automated privacy compliance research and to contribute to the solutions that promote privacy-aware use of the accountability traces. This is achieved in this dissertation through a systematic study of the existing body of knowledge in automated privacy compliance, a systematic analysis of the privacy challenges involved in processing the traces and a proposal of a privacy-aware access control model for preventing illegitimate access to the traces.
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Masrub, Abdullah Ashur. „Cognitive MAC protocols for mobile ad-hoc networks“. Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/7621.
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The term of Cognitive Radio (CR) used to indicate that spectrum radio could be accessed dynamically and opportunistically by unlicensed users. In CR Networks, Interference between nodes, hidden terminal problem, and spectrum sensing errors are big issues to be widely discussed in the research field nowadays. To improve the performance of such kind of networks, this thesis proposes Cognitive Medium Access Control (MAC) protocols for Mobile Ad-Hoc Networks (MANETs). From the concept of CR, this thesis has been able to develop a cognitive MAC framework in which a cognitive process consisting of cognitive elements is considered, which can make efficient decisions to optimise the CR network. In this context, three different scenarios to maximize the secondary user's throughput have been proposed. We found that the throughput improvement depends on the transition probabilities. However, considering the past information state of the spectrum can dramatically increases the secondary user's throughput by up to 40%. Moreover, by increasing the number of channels, the throughput of the network can be improved about 25%. Furthermore, to study the impact of Physical (PHY) Layer errors on cognitive MAC layer in MANETs, in this thesis, a Sensing Error-Aware MAC protocols for MANETs has been proposed. The developed model has been able to improve the MAC layer performance under the challenge of sensing errors. In this context, the proposed model examined two sensing error probabilities: the false alarm probability and the missed detection probability. The simulation results have shown that both probabilities could be adapted to maintain the false alarm probability at certain values to achieve good results. Finally, in this thesis, a cooperative sensing scheme with interference mitigation for Cognitive Wireless Mesh Networks (CogMesh) has been proposed. Moreover, a prioritybased traffic scenario to analyze the problem of packet delay and a novel technique for dynamic channel allocation in CogMesh is presented. Considering each channel in the system as a sub-server, the average delay of the users' packets is reduced and the cooperative sensing scenario dramatically increases the network throughput 50% more as the number of arrival rate is increased.
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Mendola, Jeffrey B. „Simulation and analysis of a time hopping spread spectrum communication system“. Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-11012008-063451/.
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Lim, Eng Chai. „Direct sequence spread spectrum multiple access system performance in an indoor milieu characterized by Rician channel“. Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/6041.
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Jaswal, Kavita. „Handoff issues in a transmit diversity system“. Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1586.
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This thesis addresses handoff issues in a WCDMA system with space-time block coded transmit antenna diversity. Soft handoff has traditionally been used in CDMA systems because of its ability to provide an improved link performance due to the inherent macro diversity. Next generation systems will incorporate transmit diversity schemes employing several transmit antennas at the base station. These schemes have been shown to improve downlink transmission performance especially capacity and quality. This research investigates the possibility that the diversity obtained through soft handoff can be compensated for by the diversity obtained in a transmit diversity system with hard handoff. We analyze the system for two performance measures, namely, the probability of bit error and the outage probability, in order to determine whether the improvement in link performance, as a result of transmit diversity in a system with hard handoffs obviates the need for soft handoffs.
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Ma, Wenjun. „AMMP-EXTN a user privacy and collaboration control framework for a multi-user collaboratory virtual reality system /“. unrestricted, 2007. http://etd.gsu.edu/theses/available/etd-09142007-204819/.
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Thesis (M.S.)--Georgia State University, 2007.Title from file title page. Ying Zhu, committee chair; G.Scott Owen, Robert W. Harrison, committee members. Electronic text (87 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Feb. 7, 2008. Includes bibliographical references (p. 84-87).
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Chen, Chi-She. „Using TD/CCSK spread spectrum technique to combat multipath interference in a multiple user system“. Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1179519410.
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Alsharekh, Mohammed Fahad. „Transform domian/cyclic code shift keying system on an urban multipath channel“. Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1177003745.
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Kaba, James, und Barbara Connolly. „Overview of the Telemetry Network System (TMNS) RF Data Link Layer“. International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581604.
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ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, CaliforniaAs the integrated Network Enhanced Telemetry (iNET) program prepares for developmental flights tests, refinements are being made to the Radio Access Network Standard that ensures interoperability of networked radio components. One key aspect of this interoperability is the definition of Telemetry Network System (TmNS) RF Data Link Layer functionality for conducting efficient communications between radios in a TDMA (Time Division Multiple Access) channel sharing scheme. This paper examines the overall structure of the TmNS RF Data Link Layer and provides an overview of its operation. Specific topics include Medium Access Control (MAC) scheduling and framing in the context of a burst-oriented TDMA structure, link layer encryption, the priority-enabled Automatic Repeat reQuest (ARQ) protocol, high-level network packet and link control message encapsulation, payload segmentation and reassembly, and radio Link Layer Control Messaging.
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Mustonen, M. (Miia). „Analysis of recent spectrum sharing concepts in policy making“. Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526216645.
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Abstract During the last couple of decades a lot of research efforts have been spent on developing different spectrum sharing concepts. As the traditional regulatory methods for spectrum allocation are proving inadequate in responding to a growing need for mobile spectrum in a timely manner and finding spectrum for exclusive use is getting increasingly difficult, the political atmosphere is also becoming more and more receptive to new innovative spectrum sharing concepts that increase the efficiency of spectrum use. These concepts also provide regulatory authorities an opportunity to fundamentally change the current major operator driven mobile market and thereby to allow new players and innovative services to surface. However, there is still a gap between the work done by the research community and the work of the regulatory authorities. In this thesis, the aim is to clarify the reasons behind this gap by analysing three prevailing regulatory spectrum sharing concepts: Licensed Shared Access, the three-tier model and TV white space concept. As different stakeholders involved in spectrum sharing – the incumbent user, the entrant user and the regulatory authority – have very diverse roles in spectrum sharing, their incentives and key criteria may vary significantly. In order for a spectrum sharing concept to have a chance in a real life deployment, all these perspectives need to be carefully considered. In fact, a feasible spectrum sharing concept is a delicate balance between the viewpoints of different stakeholders, not necessarily the one offering the most efficient spectrum utilization. This thesis analyses spectrum sharing concepts from all these perspectives and as a consequence unveils the common process model for implementing a spectrum sharing concept in real life, highlighting the distinct roles of different stakeholders in its phasesTiivistelmä Parin viimeisen vuosikymmenen aikana tutkimusyhteisö on kehittänyt valtavasti eri käsitteitä ja tuloksia taajuuksien yhteiskäyttöön. Matkapuhelinoperaattoreiden nopeasti kasvavan tiedonsiirto- ja taajuustarpeen myötä myös poliittinen ilmapiiri on muuttunut vastaanottavaisemmiksi uusille jaetuille taajuuksienkäyttömalleille, joilla voidaan sekä lisätä taajuuksien käytön tehokkuutta että mahdollistaa uusien toimijoiden ja innovatiivisten palvelujen kehitys. Taajuuksien yhteiskäyttömalleihin liittyvä tutkimustyö ei kuitenkaan usein palvele suoraan taajuusviranomaisten tarpeita. Tämän työn tavoitteena on selvittää syitä tähän kolmen vallitsevan joustavan taajuuksienkäyttökonseptin avulla: lisensoidun taajuuksien yhteiskäyttömallin, kolmitasoisen taajuuksien yhteiskäyttömallin ja TV kaistojen yhteiskäyttömallin. Eri toimijoilla on hyvin erilaiset roolit taajuuksien yhteiskäytössä ja siksi sekä heidän kannustimensa että keskeiset kriteerit voivat olla hyvin erilaiset. Käytäntöön sopiva jaetun taajuudenkäytön malli onkin usein kompromissi eri näkemysten omaavien toimijoiden kesken, ei välttämättä taajuuksien käytöltään tehokkain vaihtoehto. Tässä työssä analysoidaan eri taajuuksien yhteiskäyttömalleja sekä eri toimijoiden näkökulmia. Analyysin tuloksena luodaan yleinen prosessimalli taajuuksien yhteiskäyttömallien toteutukselle sekä identifioidaan eri toimijoiden roolit sen eri vaiheissa
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Font, Brevis Giselle Alejandra. „Privacidad de ubicación para un sistema de monitoreo de la calidad de acceso a internet móvil: Location privacy for a monitoring system of the quality of access to mobile internet“. Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/132852.
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Magíster en Ciencias, Mención ComputaciónIngeniera Civil en Computación
Con el objeto de medir la calidad de acceso a Internet móvil, NIC Chile Research Labs desarrolló Adkintun Mobile, un monitor pasivo instalado en los celulares de usuarios voluntarios. Periódicamente, la aplicación registra datos relativos al estado de la red, los que son enviados a un servidor que los recolecta. Los investigadores del laboratorio tienen acceso a los datos almacenados por el colector. A partir de la conexión a las antenas de celulares, la ubicación del dispositivo puede ser deducida, por lo que la ubicación de los usuarios queda expuesta a la vista de los investigadores, lo que resulta preocupante desde el punto de vista de la privacidad de ubicación de los individuos. Más aún, sólo cuatro puntos espacio temporales son suficientes para reidentificar al 95% de la población a partir de una base de datos anonimizada. Es por ello que este trabajo se enfoca en resolver el problema usando un enfoque criptográfico. Se propone un modelo en el que los investigadores pueden acceder, consultar y calcular agregaciones sobre los datos almacenados, pero sólo obteniendo de la ubicación de los individuos el resultado de las agregaciones. El modelo utiliza encriptación homomórfica para resguardar la privacidad de ubicación. La información relativa a la ubicación es enviada encriptada desde los celulares hacia el servidor. El servidor puede calcular homomórficamente funciones predefinidas, como contar el número de usuarios en un determinado lugar. Las consultas a la base de datos y la desencriptación, se ejecutan en capas separadas, para evitar que la llave secreta sea utilizada en la desencriptación directa de los datos. Se implementaron dos versiones de la capa de privacidad de ubicación, con encriptación completamente homomórfica (FHE) usando el esquema BGV, y con encriptación parcialmente homomórfica (PHE) usando el esquema Paillier. El desempeño y overhead del sistema, muestran que el modelo es adecuado para cálculo offline de estadísticas. Las contribuciones de este trabajo consisten en proponer una aplicación práctica de FHE para privacidad de ubicación; y discutir sobre el trade-off entre privacidad de ubicación y el desempeño del sistema en ambas implementaciones (FHE y PHE). -------------------------- In order to measure the quality of access to mobile Internet, NIC Chile Research Labs developed Adkintun Mobile, a passive monitor installed in volunteer users' mobile phones. Periodically, the client application records data related to network state, which is sent to the collector server. Researchers of the laboratory have access to such stored data. Since from connexion to antennas location can be deduced, location data of individuals is exposed to researchers, which is a concern for location privacy. Moreover, as only four spatio-temporal points are enough to identify 95\% of the population in an anonymized dataset, this work takes a cryptographic approach to solve the problem. We propose a model where researchers can access, query and compute aggregations on stored data, learning nothing more about users' location than the result of the aggregation. Our model uses homomorphic encryption to preserve location privacy. Location data is sent encrypted from mobile devices to the server. The server can homomorphically evaluate predefined functions such as counting the number of users in a given location. Query and result decryption are performed from a separate layer, which protects the secret key from being used for direct decryption of the records. We implemented two versions of the location privacy layer using a Leveled Fully Homomorphic encryption (FHE) scheme (BGV), and a Partial (additive) Homomorphic encryption (PHE) scheme (Paillier). The overhead and performance evaluation show that both versions are adequate for offline statistical analysis. The contribution of this work is to propose a practical use of FHE for location privacy; and to discuss the trade-off between location privacy and system performance for implementations using FHE and PHE.
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Al-Sharari, Hamed. „An implementation of acquisition using transform domain/cycle code shift keying system on a multipath channel“. Ohio : Ohio University, 1998. http://www.ohiolink.edu/etd/view.cgi?ohiou1177004799.
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Isohookana, M. (Matti). „Taistelunkestävä hajaspektritietovuo kansalliseen sotilasilmailuun“. Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526223728.
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Abstract The primary mission of the Finnish Air Force is to ensure a continuous surveillance and policing of the national airspace. The wartime mission is defensive counter-air fighter operations. Implementation of the air surveillance is carried out mainly with air surveillance radars – policing and defensive actions with fighters. A foundation to a well-executed flight operation is a situation awareness. Pilots have to have a real time air picture in their use, i.e., exact information of the own and enemy’s fighters, and instructions of the mission command. The later has to have information for example about the remaining flight time of the fighters. To keep up the situation awareness the fighters participating the flight operation and the mission command on the ground are connected via real time robust communications system. In this thesis, the system development of the experimental SIHTI (Suomen ilmavoimien hajaspektritietovuo) spread spectrum data link fulfilling the national requirements is considered from the requirement specification to the performance measurements of the airproof prototype. The SIHTI system, which has to be secure, robust and having good LPD/LPI (Low Probability of Detection/Low Probability of Interception) properties has to enable bidirectional transmission between fighters and base stations as well as the fighters themselves. The SIHTI system has to operate in the case when many of similar nets are operating simultaneously in the same region and under heavy jamming. The system concept and its implementation has to be configurable so that an end user and a maintenance of the system can affect on the performance of the system only via parameters and changes in algorithms. In this thesis, it will be shown that the experimental SIHTI prototype with minor changes can fulfil the set requirementsTiivistelmä Suomen ilmavoimien perustehtävä on kansallisen ilmatilan jatkuva valvonta ja vartiointi sekä sodan aikana ilmatilan puolustus. Ilmatilan valvonta hoidetaan pääasiassa ilmavalvontatutkilla – vartiointi ja puolustus sotilaskoneilla. Sotilaskoneiden tehokkaan toiminnan edellytyksenä on tilannetietoisuus. Lento-operaatioon osallistuvilla tahoilla tulee olla käytettävissä ajan tasalla oleva ilmatilannekuva eli tarkat tiedot omista ja vastapuolen koneista, taistelujohdon toimintaohjeet sekä tietoa muun muassa operaatioon osallistuvien koneiden jäljellä olevasta toiminta-ajasta. Tilannetietoisuuden ylläpitäminen edellyttää, että lento-operaatioon osallistuvia lentokoneita ja maassa olevaa taistelujohtoa yhdistää reaaliaikainen varmatoiminen tiedonsiirtoyhteys. Tässä väitöskirjassa tarkastellaan kansallisen sotilasilmailun tarpeet täyttävän lentokelpoisen SIHTI (Suomen ilmavoimien hajaspektritietovuo) -hajaspektritiedonsiirtokoejärjestelmän järjestelmäkehitystä aina vaatimusmäärittelystä lentokelpoisen koelaitteiston suorituskykymittauksiin. Turvallisen, varmatoimisen ja vaikeasti tiedusteltavan tiedonsiirtojärjestelmän tulee mahdollistaa niin lentokoneiden kuin lentokoneiden ja maa-asemien välinen kaksisuuntainen sanomansiirto useiden lähekkäin toimivien verkkojen tapauksessa hyvinkin voimakkaassa tahallisessa häirinnässä. Tiedonsiirtojärjestelmässä ja sen toteutuksessa tulee olla myös riittävä määrä muunneltavuutta, jotta järjestelmän loppukäyttäjä ja järjestelmän ylläpitäjä pystyvät parametri- ja algoritmimuutoksin vaikuttamaan järjestelmän suorituskykyyn. Väitöskirjassa osoitetaan, että FH/DS-CDMA (Frequency Hopping / Direct Sequence Code Division Multiple Access)- ja TDMA (Time Division Multiple Access) -monikäyttömenetelmiin pohjautuva SIHTI-koejärjestelmä pystyy pienin muutoksin täyttämään sille asetetut vaatimukset
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Maatougui, Lamyae. „Développement d'un récepteur intelligent dédié aux systèmes sans fil basés sur les modulations M-OAM“. Thesis, Valenciennes, 2017. http://www.theses.fr/2017VALE0015.
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Dans ces travaux de thèse, nous proposons un système de communication original permettant d’atteindre un haut débit et de répondre aux exigences de la qualité de service requise pour les communications courte portée dans le cadre du transport intelligent. Ce système se base sur la technologie Ultra Large Bande Impulsionnelle (IR-ULB) et sur un nouveau schéma de modulation nommé M-OAM (M-Orthogonal Amplitude Modulation). Les modulations M-OAM se basent sur le principe des modulations M-QAM en remplaçant les porteuses par des formes d’ondes ULB orthogonales de type MGF (Modified Gegenbauer Function). Ces modulations ont été évaluées sous les conditions d’un canal AWGN et des canaux IEEE 802.15.3a et IEEE 802.15.4a qui tiennent compte des paramètres réels de la route. En plus du haut débit exigé par les communications inter-véhiculaires, il faut assurer un échange d’informations simultané entre plusieurs utilisateurs de la route et garantir une bonne qualité de service. Dans cette optique, une nouvelle technique d’accès multiple adaptée est proposée. Chaque utilisateur a la possibilité d’utiliser la modulation OAM adéquate selon le débit désiré. Le récepteur de ce système se caractérise par un aspect intelligent grâce à l’intégration des principes de la Radio Cognitive (RC) qui permet de détecter l’arrivée du signal et d’identifier les paramètres de la modulation utilisée afin de s’y adapter d’une façon autonome. Une bonne qualité de service est assurée par la proposition d’une nouvelle technique de démodulation qui se base sur les Statistiques d’Ordres Supérieurs (SOS) permettant d’éliminer le bruit Gaussien. Les bonnes performances du système de communication M-OAM ainsi que l’ensemble des aspects proposés ont été validés expérimentalement au sein du laboratoire IEMN-DOAE. Dans la dernière partie de ce document nous avons présenté la réalisation d’un prototype de ce traitement en temps réel sur une plateforme FPGA, en exploitant des algorithmes parallélisables sur des architectures reconfigurablesIn this work of thesis, we propose an original communication system allowing to reach high data rate and to fulfill the requirements of quality of service necessary for the communications short range dedicated to intelligent transport. This system is based on the Ultra Wide Band Impulse (IR-ULB) technology and on new modulation scheme named M-OAM (M-states Orthogonal Amplitude Modulation). M-OAM modulations are based on the principle of modulations M-QAM by replacingthe carriers used for QAM modulation with orthogonal waveforms ULB type MGF (Modified Gegenbauer Function). These modulations were evaluated under the conditions of AWGN channel and IEEE 802.15 channels which take account of the real parameters of the road. Besides the high speed required by inter-vehicular communications, it is necessary to ensure simultaneous information exchange between several users of the road. Accordingly, new adaptive multiple access system is proposed. Each user has the possibility to use the adequate modulation OAM according to the desired speed. The receiver of this system is characterized by an intelligent aspect thanks to the integration of the principle of Cognitive Radio (RC) which makes it able to detect the signal arrival and to identify the parameters of the used modulation in order to adapt the demodulation in an autonomous way. A good quality of service is ensured by the proposed novel demodulation method based on the Higher Orders Statistics (HOS) to eliminate the Gaussian noise. The good performances of M-OAM communication system M-OAM as well as the whole of the suggested aspects are validated in experiments within IEMN-DOAE laboratory. In the last part of this document we presented the realization of prototype using real time processing developed on FPGA plateform and exploiting parallelisable algorithms on reconfigurable architectures
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Berrios-Ayala, Mark. „Brave New World Reloaded: Advocating for Basic Constitutional Search Protections to Apply to Cell Phones from Eavesdropping and Tracking by Government and Corporate Entities“. Honors in the Major Thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1547.
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Imagine a world where someone’s personal information is constantly compromised, where federal government entities AKA Big Brother always knows what anyone is Googling, who an individual is texting, and their emoticons on Twitter. Government entities have been doing this for years; they never cared if they were breaking the law or their moral compass of
human dignity. Every day the Federal government blatantly siphons data with programs from the original ECHELON to the new series like PRISM and Xkeyscore so they can keep their tabs on issues that are none of their business; namely, the personal lives of millions. Our allies are taking note; some are learning our bad habits, from Government Communications Headquarters’ (GCHQ) mass shadowing sharing plan to America’s Russian inspiration, SORM. Some countries are following the United States’ poster child pose of a Brave New World like order of global events. Others like Germany are showing their resolve in their disdain for the rise of tyranny. Soon, these new found surveillance troubles will test the resolve of the American Constitution and its nation’s strong love and tradition of liberty. Courts are currently at work to resolve how current concepts of liberty and privacy apply to the current conditions facing the privacy of society. It remains to be determined how liberty will be affected as well; liberty for the United States of America, for the European Union, the Russian Federation and for the people of the World in regards to the extent of privacy in today’s blurred privacy expectations.B.S.
Bachelors
Health and Public Affairs
Legal Studies
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„Security and Privacy in Dynamic Spectrum Access: Challenges and Solutions“. Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.44321.
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abstract: Dynamic spectrum access (DSA) has great potential to address worldwide spectrum shortage by enhancing spectrum efficiency. It allows unlicensed secondary users to access the under-utilized spectrum when the primary users are not transmitting. On the other hand, the open wireless medium subjects DSA systems to various security and privacy issues, which might hinder the practical deployment. This dissertation consists of two parts to discuss the potential challenges and solutions.
The first part consists of three chapters, with a focus on secondary-user authentication. Chapter One gives an overview of the challenges and existing solutions in spectrum-misuse detection. Chapter Two presents SpecGuard, the first crowdsourced spectrum-misuse detection framework for DSA systems. In SpecGuard, three novel schemes are proposed for embedding and detecting a spectrum permit at the physical layer. Chapter Three proposes SafeDSA, a novel PHY-based scheme utilizing temporal features for authenticating secondary users. In SafeDSA, the secondary user embeds his spectrum authorization into the cyclic prefix of each physical-layer symbol, which can be detected and authenticated by a verifier.
The second part also consists of three chapters, with a focus on crowdsourced spectrum sensing (CSS) with privacy consideration. CSS allows a spectrum sensing provider (SSP) to outsource the spectrum sensing to distributed mobile users. Without strong incentives and location-privacy protection in place, however, mobile users are reluctant to act as crowdsourcing workers for spectrum-sensing tasks. Chapter Four gives an overview of the challenges and existing solutions. Chapter Five presents PriCSS, where the SSP selects participants based on the exponential mechanism such that the participants' sensing cost, associated with their locations, are privacy-preserved. Chapter Six further proposes DPSense, a framework that allows the honest-but-curious SSP to select mobile users for executing spatiotemporal spectrum-sensing tasks without violating the location privacy of mobile users. By collecting perturbed location traces with differential privacy guarantee from participants, the SSP assigns spectrum-sensing tasks to participants with the consideration of both spatial and temporal factors.
Through theoretical analysis and simulations, the efficacy and effectiveness of the proposed schemes are validated.Dissertation/Thesis
Doctoral Dissertation Electrical Engineering 2017
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Crohas, Alice. „Practical implementation of a cognitive radio system for dynamic spectrum access“. 2008. http://etd.nd.edu/ETD-db/theses/available/etd-07252008-162749/.
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Thesis (M.S.E.E.)--University of Notre Dame, 2008.Thesis directed by J. Nicholas Laneman for the Department of Electrical Engineering. "July 2008." Includes bibliographical references (leaves 46-47).
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Sun, Hao-Hsiang, und 孫浩翔. „Fuzzy Active Period Adaptation for Dynamic Spectrum Access in IEEE 802.16h System“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/84502675184761949241.
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碩士國立交通大學
電信工程系所
96
With the development of communication technology, wireless communications become more important to provide convenient services. It triggers a huge demand for bandwidth for transmission. Because of the spectrum scarcity, how to use the spectrum dynamically and efficiently becomes an important issue. Dynamic spectrum access (DSA) is a promising approach to alleviate the spectrum scarcity that wireless communications face today. To provide the mechanism of DSA networks, the use of “cognitive radio” (CR) technology is viewed as the key technology to fully utilize the bandwidth. In this thesis, a CR-based dynamic spectrum access (DSA) device named fuzzy active period adaptor (FAPA) is proposed in downlink transmission of IEEE 802.16h systems. FAPA decides the active period of CR system to efficiently coexist with WLAN system in 802.16h system. Simulation results show the fuzzy active period adaptation can improve the overall throughput and reduce the idle time of the spectrum with slightly interfering in the operation of the primary WLAN system.
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Chan, Kai-Tung, und 詹凱同. „A Novel Comb-Spectrum Code Division Multiple Access Uplink System Using Sparse Gaussian Integer Perfect Sequences“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/51572599451870014550.
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碩士國立中山大學
電機工程學系研究所
101
Multi-Carrier Code Division Multiple Access (MC-CDMA) is a promising approach to the challenge of providing high data rate wireless communication. It can be interpreted as CDMA with the spreading taking place in the frequency rather than temporal domain. However, due to the frequency selective fading channel for uplink, the orthogonality among various spreading codes is lost and it causes multi-user interference (MUI). Recently, the comb-spectrum (CS) CDMA system without MUI was proposed. One user’s data are spread on an assigned interleaved subcarrier group. Since a subcarrier is only assigned to one user. Therefore, for uplink, the orthogonality among spreading codes can be restored perfectly in the frequency selective fading channel. However, the spectrum of the CS code is not flat and parts of spectrum are zeros which cause the bit error rate (BER) degradation. A sequence of complex number is called Sparse Gaussian Integer Perfect Sequence (SGIPS) whose real parts and imaginary parts are both integers and whose any cyclic shift is orthogonal to each other. Moreover, the number of nonzero elements of GIPS is independent on the sequence length and much less than the sequence length. In this paper, the SGIPS is utilized as the spreading codes and a novel comb-spectrum code division multiple access system is proposed. From simulation results, the BER of the proposed systems is better than the traditional CS-CDMA systems. For quadrature phase shift keying, the proposed scheme gains about 3dB when BER = 10-4.
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HSIEH, TSUNG-HSIEN, und 謝宗憲. „A novel comb-spectrum code division multiple access downlink system using sparse gaussian integer perfect sequences“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/5rbgc3.
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碩士國立中山大學
電機工程學系研究所
102
Multi-carrier code division multiple Access (MC-CDMA) is a promising approach to the challenge of providing high data rate wireless communication. It can be interpreted as CDMA with the spreading taking place in the frequency rather than temporal domain. However, one of drawbacks of MC-CDMA systems is high peak-to-average power ratio. Recently, the comb-spectrum (CS) CDMA system was proposed. One user’s data are spread on an assigned interleaved subcarrier group. In addition, the corresponding CS codes in the time domain are of equal magnitude. Therefore, the peak-to-average power ratio can be reduced. However, the spectrum of the CS code is not flat and parts of spectrum are zeros which cause the bit error rate (BER) degradation. A sequence of complex number is called sparse Gaussian integer perfect sequence (SGIPS) whose real parts and imaginary parts are both integers and whose any cyclic shift is orthogonal to each other. Moreover, the number of nonzero elements of GIPS is independent on the sequence length and much less than the sequence length. In this paper, the SGIPS is utilized as the spreading codes and a novel comb-spectrum code division multiple access system is proposed. From simulation results, the BER of the proposed systems is better than the traditional CS-CDMA systems. For quadrature phase shift keying, the proposed scheme gains about 3dB when BER = 10-4.
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Tekle, Solomon Mekonnen. „A Privacy-Preserving, Context-Aware, Insider Threat prevention and prediction model (PPCAITPP)“. Thesis, 2018. http://hdl.handle.net/10500/25968.
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The insider threat problem is extremely challenging to address, as it is committed by insiders who are
trusted and authorized to access the information resources of the organization. The problem is further
complicated by the multifaceted nature of insiders, as human beings have various motivations and
fluctuating behaviours. Additionally, typical monitoring systems may violate the privacy of insiders.
Consequently, there is a need to consider a comprehensive approach to mitigate insider threats. This
research presents a novel insider threat prevention and prediction model, combining several approaches,
techniques and tools from the fields of computer science and criminology. The model is a Privacy-
Preserving, Context-Aware, Insider Threat Prevention and Prediction model (PPCAITPP). The model is
predicated on the Fraud Diamond (a theory from Criminology) which assumes there must be four elements
present in order for a criminal to commit maleficence. The basic elements are pressure (i.e. motive),
opportunity, ability (i.e. capability) and rationalization. According to the Fraud Diamond, malicious
employees need to have a motive, opportunity and the capability to commit fraud. Additionally, criminals
tend to rationalize their malicious actions in order for them to ease their cognitive dissonance towards
maleficence. In order to mitigate the insider threat comprehensively, there is a need to consider all the
elements of the Fraud Diamond because insider threat crime is also related to elements of the Fraud
Diamond similar to crimes committed within the physical landscape.
The model intends to act within context, which implies that when the model offers predictions about threats,
it also reacts to prevent the threat from becoming a future threat instantaneously. To collect information
about insiders for the purposes of prediction, there is a need to collect current information, as the motives
and behaviours of humans are transient. Context-aware systems are used in the model to collect current
information about insiders related to motive and ability as well as to determine whether insiders exploit any
opportunity to commit a crime (i.e. entrapment). Furthermore, they are used to neutralize any
rationalizations the insider may have via neutralization mitigation, thus preventing the insider from
committing a future crime. However, the model collects private information and involves entrapment that
will be deemed unethical. A model that does not preserve the privacy of insiders may cause them to feel
they are not trusted, which in turn may affect their productivity in the workplace negatively. Hence, this
thesis argues that an insider prediction model must be privacy-preserving in order to prevent further
cybercrime. The model is not intended to be punitive but rather a strategy to prevent current insiders from
being tempted to commit a crime in future.
The model involves four major components: context awareness, opportunity facilitation, neutralization
mitigation and privacy preservation. The model implements a context analyser to collect information related
to an insider who may be motivated to commit a crime and his or her ability to implement an attack plan.
The context analyser only collects meta-data such as search behaviour, file access, logins, use of keystrokes
and linguistic features, excluding the content to preserve the privacy of insiders. The model also employs
keystroke and linguistic features based on typing patterns to collect information about any change in an
insider’s emotional and stress levels. This is indirectly related to the motivation to commit a cybercrime.
Research demonstrates that most of the insiders who have committed a crime have experienced a negative
emotion/pressure resulting from dissatisfaction with employment measures such as terminations, transfers
without their consent or denial of a wage increase. However, there may also be personal problems such as a
divorce. The typing pattern analyser and other resource usage behaviours aid in identifying an insider who
may be motivated to commit a cybercrime based on his or her stress levels and emotions as well as the
change in resource usage behaviour. The model does not identify the motive itself, but rather identifies those
individuals who may be motivated to commit a crime by reviewing their computer-based actions. The model
also assesses the capability of insiders to commit a planned attack based on their usage of computer
applications and measuring their sophistication in terms of the range of knowledge, depth of knowledge and
skill as well as assessing the number of systems errors and warnings generated while using the applications.
The model will facilitate an opportunity to commit a crime by using honeypots to determine whether a
motivated and capable insider will exploit any opportunity in the organization involving a criminal act.
Based on the insider’s reaction to the opportunity presented via a honeypot, the model will deploy an
implementation strategy based on neutralization mitigation. Neutralization mitigation is the process of
nullifying the rationalizations that the insider may have had for committing the crime. All information about
insiders will be anonymized to remove any identifiers for the purpose of preserving the privacy of insiders.
The model also intends to identify any new behaviour that may result during the course of implementation.
This research contributes to existing scientific knowledge in the insider threat domain and can be used as a
point of departure for future researchers in the area. Organizations could use the model as a framework to
design and develop a comprehensive security solution for insider threat problems. The model concept can
also be integrated into existing information security systems that address the insider threat problemInformation Science
D. Phil. (Information Systems)
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Ellis, Timothy. „The implementation of a CDMA system on a FPGA-based software radio“. Thesis, 2000. http://hdl.handle.net/10413/5252.
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This dissertation exammes two of the rlsing technologies in the world of wireless, cellular
communications - CDMA and the software radio. This thesis covers many of the issues related
to these two emerging field s of wireless communications, establish ing a theoretical framework
for the broader issues of implementation. To this end, the thesis covers many of the basic issues
of spread spectrum communications, in addition to establishing the need for, and defining the
role of, the software radio. Amalgamation of these two key areas of interest is embellished in a
presentation of many of the concerns of implementing a specific CDMA system on a particular
type of software radio - the Alcatel Altech Telecomms Flexible Radio Platform.
Of primary concern in the research methodology embraced in this thesis is the mastering of a
variety of analysis and implementation tools. Once the theoretical background has been
substantiated by current expositions, the thesis launches along a highly deterministic route.
First, the research issues are tested in a mathematical environment for suitability to the given
task. Second, an analysis of the appropriateness of the technique for the software radio
environment is undertaken, culminating in the attempted deployment within the hardware
environmenl. Rigorous testing of the input/output mapping characteristics of the hardware
instantiations created in this manner complements the research methodology with a viability
study. This procedure is repeated with many elements of the CDMA system design as they are
examined, simu lated, deployed and tested.Thesis (M.Sc.Eng.)-University of Natal, Durban, 2000.
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Santhosam, Charles L. „CDMA Base Station Receive Co-Processor Architecture“. Thesis, 2004. http://hdl.handle.net/2005/318.
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Third generation mobile communication systems promise a greater data rate and new services to the mobile subscribers. 3G systems support up to 2 Mbps of data rate to a fixed subscriber and 144 Kbps of data rate to a fully mobile subscriber. Code Division Multiple Access (CDMA) is the air interface access scheme widely used in all the 3G communication systems. This access scheme has many inherent advantages m terms of noise immunity, security, coherent combining of multi path signals etc. But all these advantages come at the expense of higher complexity of the receivers. The receivers form the major portion of the processing involved in a base station. The heart of any CDMA receiver is the RAKE. The RAKE receiver separates the different multi-paths received by the antenna by using the properties of the Pseudo Random sequences. The phase and strength of each of these path signals is measured and are used by the coherent combiner, which de-rotates all the signals to a single reference and coherently combines them In general the Base station receivers make use of the top three multi-path signals ranked in terms of their signal energy Hence four RAKE fingers, each catering to single multi-path are needed for receiving a single code channel (3 for coherent combining and one for scanning). One such channel receiver requires a processing power of 860 MIPS (Mega Instructions Per Second). Some of the CDMA standards support up to 90 code channels at the same time. This means that the total processing power required at the base station is about 80 GIPS. This much of processing power will require large number of high end DSPs, which will be a very costly solution. In the current base station architectures these blocks are implemented using ASICs, which are specific to a particular standard and also the algorithms used for the different operations are fixed at the design time itself. This solution is not flexible and is not amenable for SDR (Software defined Radio) architectures for the Base stations.
This thesis proposes a Co-Processor solution, which can be attached to a generic DSP or any other processor. The processor can control the Co-Processor by programming its parameter registers using memory mapped register accesses. This co-processor implements only those blocks, which are compute intensive. This co-processor performs all chip-rate processing functions involved m a RAKE receiver. All the symbol-rate functions are implemented through software in the processor. This provides more choices m selecting the algorithms for timing recovery and scanning. The algorithms can be changed through software even after the base station is installed in the field.
All the inputs and outputs of the Co-Processor are passed through dual port RAMs with independent read and write clocks. This allows the Co-Processor and the processor to be running on two independent clocks. This memory scheme also increases the throughput as the reads and writes to these memories can happen simultaneously. This thesis introduces a concept of incorporating programmable PN/Gold code generators as part of the Co-Processor, which significantly reduces the amount of memory required to store the Scrambling and Spreading codes. The polynomial lengths as well as the polynomials of the code generator are programmable.
The input signal memory has a bus width equal to 4 times the bus width of the IQ signal bus width (4 * 24 = 96 bits) towards the Co-Processor to meet the huge data bandwidth requirement. This memory is arranged as word interleaved memory banks. This can supply one word per memory bank on each clock cycle as long as the accessed words fall in different memory banks. The number of banks is chosen as more than twice that of the number of Correlators/ Rake fingers. This gives more flexibility in choosing the address offsets to different Correlator inputs. This flexibility allows one to use different timing recovery schemes since the number of allowable address offsets for different Correlators is more.
The overall complexity of the solution is comparatively less with respect to the generic DSP based solution and much easier to modify for a different standard, when compared to the rigid ASIC based solution. The proposed solution is significantly different from the conventional way of designing the Base station with fixed ASICs and it clearly outweighs the solutions based on conventional approach in terms of flexibility, design complexity, design time and cost.
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(6620474), Denis A. Ulybyshev. „Data Protection in Transit and at Rest with Leakage Detection“. Thesis, 2019.
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In service-oriented architecture, services can communicate and share data among themselves. This thesis presents a solution that allows detecting several types of data leakages made by authorized insiders to unauthorized services. My solution provides role-based and attribute-based access control for data so that each service can access only those data subsets for which the service is authorized, considering a context and service’s attributes such as security level of the web browser and trust level of service. My approach provides data protection in transit and at rest for both centralized and peer-to-peer service architectures. The methodology ensures confidentiality and integrity of data, including data stored in untrusted cloud. In addition to protecting data against malicious or curious cloud or database administrators, the capability of running a search through encrypted data, using SQL queries, and building analytics over encrypted data is supported. My solution is implemented in the “WAXEDPRUNE” (Web-based Access to Encrypted Data Processing in Untrusted Environments) project, funded by Northrop Grumman Cybersecurity Research Consortium. WAXEDPRUNE methodology is illustrated in this thesis for two use cases, including a Hospital Information System with secure storage and exchange of Electronic Health Records and a Vehicle-to-Everything communication system with secure exchange of vehicle’s and drivers’ data, as well as data on road events and road hazards.
To help with investigating data leakage incidents in service-oriented architecture, integrity of provenance data needs to be guaranteed. For that purpose, I integrate WAXEDPRUNE with IBM Hyperledger Fabric blockchain network, so that every data access, transfer or update is recorded in a public blockchain ledger, is non-repudiatable and can be verified at any time in the future. The work on this project, called “Blockhub,” is in progress.
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Menhaj, Lamyae. „Développement d'un récepteur intelligent dédié aux systèmes sans fil basés sur les modulations M-OAM“. Thesis, 2017. http://www.theses.fr/2017VALE0015/document.
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Dans ces travaux de thèse, nous proposons un système de communication original permettant d’atteindre un haut débit et de répondre aux exigences de la qualité de service requise pour les communications courte portée dans le cadre du transport intelligent. Ce système se base sur la technologie Ultra Large Bande Impulsionnelle (IR-ULB) et sur un nouveau schéma de modulation nommé M-OAM (M-Orthogonal Amplitude Modulation). Les modulations M-OAM se basent sur le principe des modulations M-QAM en remplaçant les porteuses par des formes d’ondes ULB orthogonales de type MGF (Modified Gegenbauer Function). Ces modulations ont été évaluées sous les conditions d’un canal AWGN et des canaux IEEE 802.15.3a et IEEE 802.15.4a qui tiennent compte des paramètres réels de la route. En plus du haut débit exigé par les communications inter-véhiculaires, il faut assurer un échange d’informations simultané entre plusieurs utilisateurs de la route et garantir une bonne qualité de service. Dans cette optique, une nouvelle technique d’accès multiple adaptée est proposée. Chaque utilisateur a la possibilité d’utiliser la modulation OAM adéquate selon le débit désiré. Le récepteur de ce système se caractérise par un aspect intelligent grâce à l’intégration des principes de la Radio Cognitive (RC) qui permet de détecter l’arrivée du signal et d’identifier les paramètres de la modulation utilisée afin de s’y adapter d’une façon autonome. Une bonne qualité de service est assurée par la proposition d’une nouvelle technique de démodulation qui se base sur les Statistiques d’Ordres Supérieurs (SOS) permettant d’éliminer le bruit Gaussien. Les bonnes performances du système de communication M-OAM ainsi que l’ensemble des aspects proposés ont été validés expérimentalement au sein du laboratoire IEMN-DOAE. Dans la dernière partie de ce document nous avons présenté la réalisation d’un prototype de ce traitement en temps réel sur une plateforme FPGA, en exploitant des algorithmes parallélisables sur des architectures reconfigurablesIn this work of thesis, we propose an original communication system allowing to reach high data rate and to fulfill the requirements of quality of service necessary for the communications short range dedicated to intelligent transport. This system is based on the Ultra Wide Band Impulse (IR-ULB) technology and on new modulation scheme named M-OAM (M-states Orthogonal Amplitude Modulation). M-OAM modulations are based on the principle of modulations M-QAM by replacingthe carriers used for QAM modulation with orthogonal waveforms ULB type MGF (Modified Gegenbauer Function). These modulations were evaluated under the conditions of AWGN channel and IEEE 802.15 channels which take account of the real parameters of the road. Besides the high speed required by inter-vehicular communications, it is necessary to ensure simultaneous information exchange between several users of the road. Accordingly, new adaptive multiple access system is proposed. Each user has the possibility to use the adequate modulation OAM according to the desired speed. The receiver of this system is characterized by an intelligent aspect thanks to the integration of the principle of Cognitive Radio (RC) which makes it able to detect the signal arrival and to identify the parameters of the used modulation in order to adapt the demodulation in an autonomous way. A good quality of service is ensured by the proposed novel demodulation method based on the Higher Orders Statistics (HOS) to eliminate the Gaussian noise. The good performances of M-OAM communication system M-OAM as well as the whole of the suggested aspects are validated in experiments within IEMN-DOAE laboratory. In the last part of this document we presented the realization of prototype using real time processing developed on FPGA plateform and exploiting parallelisable algorithms on reconfigurable architectures