1,257 research outputs found
Cooperative secure transmission relying on the optimal power allocation in the presence of untrusted relays, a passive eavesdropper and hardware impairments
No full textIn this work, by considering a variety of realistic hardware impairments, we aim to enhance the security of a cooperative relaying network, where a source intends to transmit its confidential information to a destination in the presence of a group of untrusted amplify-and-forward relays, as potential eavesdroppers (Eves), and an entirely passive multiple-antenna aided Eve. Our goal is to safeguard the information against these two types of eavesdropping attacks, while simultaneously relying on the untrusted relays to boost both the security and reliability of the network. To reach this goal, we propose a novel joint cooperative beamforming, jamming and power allocation policy to safeguard the confidential information while concurrently achieving the required quality-of-service at the destination. We also take into account both the total power budget constraint and a practical individual power constraint for each node. Our optimization problem can be split into two consecutive sub-problems. In the first sub-problem, we are faced with a non-convex problem which can be transformed into the powerful difference of convex (DC) program. A low-complexity iterative algorithm is proposed to solve the DC program, which relies on the constrained concave-convex procedure (CCCP). We further introduce a novel initialization method, which is based on a feasible point of the original problem obtained from a novel iterative feasibility search procedure, rather than an arbitrary (infeasible) point as in the conventional CCCP. The second sub-problem of our optimization problem is a convex optimization problem and can be solved efficiently adopting the classic interior point method. The numerical results provided illustrate that although the trusted relaying scenario outperforms the untrusted relaying for small and medium total power budgets, however, by increasing the total power budget, the secrecy performances of both the trusted and untrusted relaying converge to the same. Additionally, by equally sharing the total impairments at the relays between the transmitter and the receiver the best secrecy performance is presented
Maximizing the secrecy energy efficiency of the cooperative rate-splitting aided downlink in multi-carrier UAV networks
No full textAlthough Unmanned Aerial Vehicles (UAVs) are capable of significantly improving the information security by detecting the eavesdropper's location, their limited energy motivates our research to propose a secure and energy efficient scheme. Thanks to the common-message philosophy introduced by Rate-Splitting (RS), we no longer have to allocate a portion of the transmit power to radiate Artificial Noise (AN), and yet both the Energy Efficiency (EE) and secrecy can be improved. Hence we define and study the Secrecy Energy Efficiency (SEE) of a multi-carrier multi-UAV network, in which Cooperative Rate-Splitting (CRS) is employed by each multi-antenna UAV Base-Station (UAV-BS) for protecting their downlink transmissions against an external eavesdropper (Eve). Furthermore, we consider the challenging scenario in which CRS is employed by each multi-antenna UAV-BS to protect their corresponding downlink transmissions against an external Eve. We further consider a difficult scenario in terms of security in which only imperfect channel state information of Eve is available at the Tx. Accordingly, we conceive a robust secure resource allocation algorithm, which maximizes the SEE by jointly optimizing both the user association matrix and the network parameter allocation problem, including the RS precoders, time slot sharing and power allocation. Due to the non-convexity of the problem, it is decoupled into a pair of convex sub-problems. Firstly, new two-tier intra-cell optimization problems are formulated for achieving ξ-optimal solutions by iterative block coordinate decent programming. Then, the power of each sub-channel is optimized by formulating the associated power control problem. Simulation results confirm that the scheme conceived enhances both the secrecy and energy efficiency of the system compared to the existing cooperative non-orthogonal benchmarks
Large-scale rate-splitting multiple access in uplink UAV networks: effective secrecy throughput maximization under limited feedback channel
No full textUnmanned aerial vehicles (UAVs) are capable of improving the performance of next generation wireless systems. However, their communication performance is prone to both channel estimation errors and potential eavesdropping. Hence, we investigate the effective network secrecy throughput (ENST) of the uplink UAV network, in which rate-splitting multiple access (RSMA) is employed by each legitimate user for secure transmission under the scenario of massive access. To maximize the ENST, the transmission rate versus power allocation relationship is formulated as a max-min optimization problem, relying on realistic imperfect channel state information (CSI) of both the legitimate users and passive eavesdroppers (Eves). In the model considered, each user transmits a superposition of two messages to a UAV base-stations (UAV-BS), each having different transmit power and the UAV-BS adopts a successive interference cancellation (SIC) technique to decode the received messages. Given the non-convexity of the problem, it is decoupled into a pair of sub-problems. In particular, we derive a closed form expression for the optimal rate-splitting fraction of each user. Then, given the optimal rate-splitting fraction of each user, the \epsilon-constrainted transmit power of each user is calculated by harnessing sequential parametric convex approximation (SPCA) programming. Our simulation results confirm that the scheme conceived significantly improves the ENST compared to both the existing orthogonal and non-orthogonal benchmarks.</p
On the physical layer security of the cooperative rate-splitting aided downlink in UAV networks
No full textUnmanned Aerial Vehicles (UAVs) have found compelling applications in intelligent logistics, search and rescue as well as in air-borne Base Station (BS). However, their communications are prone to both channel errors and eavesdropping. Hence, we investigate the max-min secrecy fairness of UAV-aided cellular networks, in which Cooperative Rate-Splitting (CRS) aided downlink transmissions are employed by each multi-antenna UAV Base Station (UAV-BS) to safeguard the downlink of a two-user Multi-Input Single-Output (MISO) system against an external multi-antenna Eavesdropper ( Eve ). Realistically, only Imperfect Channel State Information (ICSI) is assumed to be available at the transmitter. Additionally, we consider a realistic total power constraint and guarantee the specific Quality of Service (QoS) requirements of the legitimate users. To handle the worst-case channel uncertainty of the legitimate users and an external Eve , we conceive a robust secure resource allocation algorithm, which maximizes the minimum worst-case secrecy rate of the legitimate users. Based on the CRS principle, the transmitter splits and encodes the messages of legitimate users into common as well as private streams and the user having stronger CSI is asked to help the cell-edge user by opportunistically forwarding its decoded common message. In contrast to the existing schemes adopted in the literature for ensuring secure transmission of the first cooperative phase only, in our proposed solution the common message has a twin-fold mission. Explicitly, apart from serving as the desired message, it also acts as Artificial Noise (AN) for drowning out Eve without consuming extra power. This is in stark contrast to the conventional AN designs. In the second phase, the pure AN is directed towards the Eve , deploying a robust Maximum Ratio Transmitter (MRT) beamformer at the UAV-BS. To solve the resultant non-convex optimization problem we resort to the Sequential Parametric Convex Approximation (SPCA) method together with a bespoke initialization algorithm to avoid any failure due to infeasibility. Our simulation results confirm that the proposed secure transmission scheme outperforms the existing cooperative benchmarkers.</p
MEMPERTIMBANGKAN NILAI ADIL DALAM WARISAN (Perspektif Nasr Hamid Abu Zayd)
No full textNasr Hamid Abu Zayd who has some thoughts related to the Qur'an is a contemporary Islamic critical thinker . He said that al Qur’an is a cultural product, this statement made him get under public criticism. However, besides that there are interesting things in the thought of Nasr Hamid Abu Zayd when discussing gender issues including in terms of division of inheritance which according to the author has not been known to the public. The idea that carried Nasr Hamid Abu Zayd is what the author needs to describe conceptually. Research on Gender Deconstruction Perspective Nasr Hamid Abu Zayd was done in order to answer: 1) How is the Qur'an according to Nasr Hamid Abu Zayd? 2) How is the legacy in the Qur'an according to Nasr Hamid Abu Zayd? This paper would like to reconstruct the thoughts of Nasr Hamid Abu Zayd on the Qur'an and the concept of justice in the inheritance. In order to reconstruct the thought of Nasr Hamid Abu Zayd, the author used theoretical hermeneutical of Schleirmacher’s. theory
Antenna and pulse selection for colocated MIMO radar
No full textMultiple input multiple output (MIMO) radar is known for its superiority over conventional radar due to its antenna and waveform diversity. However, the increased hardware cost (due to multiple transmitters and receivers), power consumption (due to multiple transmitters and pulses), and computational complexity (due to numerous pulses) form the drawbacks of MIMO radar. On one hand, a higher estimation accuracy is required, but on the other hand, a lower number of active antennas/pulses is desirable. Therefore, in this paper, by proposing a convex optimization approach for the general case of transmitter-receiver-pulse selection, we will minimize the total number of active antennas/pulses in order to guarantee a prescribed performance accuracy. The performance measure we will optimize is the Cramer-Rao lower bound (CRLB) for the angle and velocity estimation accuracy of two targets, which provides a trade-off between the main beamwidth and the sidelobe level (SLL) of the ambiguity function.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Signal Processing System
Reliability updating of experienced Hydraulic Structures by account of inspections: Case study: Poiree weir Roermond
No full textThe Dutch Ministry of Infrastructure and Environment manages approximately five hundred hydraulic structures and is responsible for the remaining life of these experienced structures. In this report, we developed a reliability analysis for the case study poiree weir Roermond. The inspections carried out by IV-Infra on the poiree weir Roermond concludes a rise to high risk e.g. a high probability of occurrence and major consequential loss primarily related to the observed erosion damage at the embedded poiree trestles located upstream river. The remaining life of hydraulic structures is in general the expected lifespan, on the condition that the structure does not fail in the expected lifespan also known as ‘reference period’. The remaining life can be determined as one can predict the deterioration and be able to predict in what condition the poiree weir will be. When the service life time is assumed a random variable, the strength condition can be modeled as a stochastic process, and thus the remaining life too. There is doubt concerning the structural safety because of this deterioration, a reliability assessment of experienced hydraulic structures must be therefore reviewed for use during the remaining life instead of the general reference period and are therefore not to be considered equal.The lognormal distribution with skewness k<1 is an appropriate method to model the strength deterioration behavior. The future condition can’t be exactly determined because of the introduction of the deterioration model uncertainty. Nevertheless, the effect of the inspection data on the reliability level can be illustrated by the likelihood of the strength at the moment of inspection and can be estimated better with a Bayesian afterwards probability. The increase of the actual number of inspections further reduces the uncertainty of the strength deterioration.The Dutch Ministry of Infrastructure introduced the "experienced reliability level". The experienced reliability level is the minimum level of structural safety for experienced structures in main waterways. For the reference period and remaining life of 30 years, the following reliability index β = 3.3 is the lower limit for the structural safety for existing structures. The survival probabilities can then be given as reliability index, and compared with the minimum reliability level of experienced structures. To maintain the reliability level at the target level, the remaining life of the poiree weir is the period within which the minimum reliability level of experienced structures should not be less. The remaining life for without inspections and n=9 inspections is calibrated to 7 years, the increase of the number observations n=100 increases the remaining service life to 11 years. One can say that inspection increases the remaining life. This is great of importance for the planning of maintenance.Dutch Ministry of Infrastructure and EnvironmentExperienced reliability level of hydraulic structuresPoiree weir RoermondMaster project reportMaster internshi
Book review: Crunch time: how married couples confront unemployment by Aliya Hamid Rao
No full textIn Crunch Time: How Married Couples Confront Unemployment, Aliya Hamid Rao offers a new addition to sociological research on unemployment, delving into the ways that gender beliefs unequally shape men’s and women’s experiences of job search and unemployment. Sarah Damaske recommends this wonderful and engagingly written book for introducing a much-needed gender and work-family lens to the unemployment literature. If you are interested in this book review, you can read an interview with author Dr Aliya Hamid Rao on Crunch Time and the implications of its findings during the COVID-19 pandemic. Crunch Time: How Married Couples Confront Unemployment. Aliya Hamid Rao. University of California Press. 2020
Analysis of Hamid Mawlana's Thoughts on Islamic Communication Theory
No full textThis paper explores Islamic communication theory developed by Hamid Mowlana (1979, 1993, 2007). The analysis includes the context of the emergence of a discourse on Islamic communication in the academic realm and the elaboration and criticism of the substance of Hamid Mowlana’s Islamic communication theory. Using the literature study method, the author found that the emergence of Islamic communication theory was motivated by the meeting of two streams of criticism of Western science, namely the criticism of Islamic intellectuals against the paradigm of Western social science (and therefore, against western modernization); and the tendency towards international communication studies by emphasizing the DE westernization approach, motivated by the cultural turn in the development of the social sciences. Hamid Mowlana formulated Islamic communication theory by proposing the concept of tabligh initially developed from his studies of communication practices and systems in Iran, especially around the period before and after the revolution. Tabligh, besides being a theory, is also an ethic and is based on five fundamental principles: Tauhid, Amar ma’ruf nahi munkar, Ummah, Taqwa, and Amanah. Hamid Mowlana’s Islamic communication theory has its weaknesses, especially in its basic assumptions about Islamic exceptionalism and the singularity of Islamic and Western civilizations
PEMIKIRAN GERAKAN TURKI MUDA DALAM UPAYA MENJATUHKAN SULTAN ABDUL HAMID II (1876-1909 M)
No full text<p>The purpose of this research are (1) to find the factors of the Young Turks Movement wanted to attempt the Sultan Abdul Hamid II and (2) to describe the consideration of Young Turk Movement in bringing down Sultan Abdul Hamid II. This study uses qualitative methods presented in descriptive. The technique of data collection was done through the study of library research. Books that became reference were book related to considerations of Young Turk and Sultan Abdul Hamid II. The author did data selection from the rest of the data obtained and then did the analysis. The results of the findings in this research are first, the Young Turks are movement against the reign of Sultan Abdul Hamid II which they regard as dictator. The Young Turk cooperated with liberal opposition to get rid of Sultan abdul Hamid II from his power. Second,the consideration of Young Turk Movement in bringing down Sultan Abdul Hamid II, is build a partnership with Zionism, replacing the Sultan, assault and murder.</p></jats:p
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