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Robustness of Entanglement-Free Quantum Byzantine Agreement
Muhammad Asad Ullah,Jason William Setiawan,Junaid ur Rehman,Hyundong Shin 한국통신학회 2022 한국통신학회 학술대회논문집 Vol.2022 No.2
Byzantine agreement refers to a consensus mechanism between distributed nodes in a network in the presence of faulty parties. For any consensus algorithm, three primary performance measures are: scalability, security, and decentralization. Quantum mechanics provides non-classical resources including entanglement and coherence with unparalleled advantages in cryptography, synchronization, and secret sharing. Based on these resources, various quantum Byzantine agreement (QBA) algorithms have been proposed but they have not been evaluated for the aforementioned performance measures. In this paper, we provide two contributions. First, we evaluate the usefulness and practicality of these quantum consensus algorithms. We observe that in contrast to their classical counterparts, in general, quantum consensus algorithms have better security, lower scalability, and comparable decentralization. Secondly, we investigate the noise robustness of the entanglement-free scheme which is one of the most scalable QBAs to date. We observe that the local qubit noise and channel decoherence increase the error rate in the list distribution, thereby decreasing the number of consensus per second. We infer that the current quantum protocols with noisy intermediate-scale quantum (NISQ) devices and noisy quantum communication can only be employed in small scale networks.
Photon Dynamics in Counterfactual Quantum Communication
Muhammad Asad Ullah,Junaid ur Rehman,Hyundong Shin(신현동) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.2
We investigate the evolution of a photon’s wave-function as it traverses through the polarization beam splitter (PBS)-based Michelson interferometer (PBS-MI). The PBS-MI provides the basis for particle-less counterfactual communication. We investigate the change in photon state evolution due to delay in the channel arm of PBS-MI in the practical implementation. This is due to the mismatched path lengths of the interferometer leading to the evolution in the path degree of freedom of the photon. We analyze the mismatched path lengths in practical implementation of nested interferometers based counterfactual communication schemes for particle-less information transfer and clock synchronization lead to increased infidelity of the output state.
Khalid, Muhammad Asad Ullah,Kim, Young Soo,Ali, Muhsin,Lee, Byung Gul,Cho, Young-Jae,Choi, Kyung Hyun Elsevier 2020 Biochemical engineering journal Vol.155 No.-
<P><B>Abstract</B></P> <P>Numerous micro-physiological systems have been reported to successfully mimic the organ microenvironment. However, there are currently only a few systems that focus on real-time physiological monitoring for preclinical cytotoxicity assessment of drug candidates. We developed a multi-sensor lung cancer-on-chip platform for trans-epithelial electrical (TEER) impedance based cytotoxicity evaluation of drug candidates. The excellent transparency of ITO electrodes allowed for visual monitoring of cells on chip using a 3D-printed digital microscope, which has not been previously reported. An optical pH sensor was used for online monitoring of media pH. As a proof of concept, lung cancer NCI-H1437 cells were cultured on glass-based microfluidic chip and biosensors data were obtained in real-time. The toxicity of different concentrations of drugs doxorubicin (DOX) and docetaxel was then monitored in real-time using the TEER impedance sensor. The TEER impedance response was evaluated in terms of cell index (CI), whereas a live/dead assay was performed for the comparison of cell viability at the end of the experiments. The cell index assessment suggested that the increasing concentrations of doxorubicin resulted in a higher cell death rate than docetaxel. The pH response and microscopic images were also recorded during drug treatment. The platform we developed here, is a promising tool for the cytotoxicity evaluation of novel drug compounds for future micro-physiological systems and development of personalized medicine.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A lung cancer-on-chip platform was developed for real-time physiological monitoring. </LI> <LI> All the biosensors were developed in-house including pH, and TEER impedance sensors. </LI> <LI> Transparent ITO electrode allowed for visual monitoring using 3D-printed microscope. </LI> <LI> The toxicity of anticancer drugs doxorubicin and docetaxel was evaluated. </LI> <LI> A comparison of impedimetric and live/dead cell viabilities was also analyzed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
A Multi-layer Parallel Crack Extension Model for Deformational Response of Post-installed Anchor
Muhammad Saleem,Asad Ullah Qazi,Asif Hameed,Muhammad Aun Bashir 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.5
A simultaneous crack extension pull-out model for post-installed anchor bar is presented. The anchor bar is such that used in various strengthening techniques to strengthen reinforced concrete structures. The properties of the infill material used for postinstalled anchor bar are characterized by a nonlinear interface between the surrounding concrete and the anchor bar. This is a new type of anchor-infill assembly in which the infill material is divided into two layers for the purpose of providing a larger failure path length resulting in increase of the energy absorption and pull-out load capacity. The mechanical properties of the infill layer are different from the surrounding concrete. Therefore the existing pull-out model of deformed bars cannot be applied directly in this case. The interfacial de-bonding is examined by the strength criterion expressed in terms of interfacial shear stress. Pre-existing cracks representing artificial notches are assumed at the top of infill layers for identifying crack location and stabilizing its propagation direction. All the possibilities associated with two-cracks in the close vicinity have been investigated in detail. The objective of the analysis is to predict a set of material properties which result in simultaneous crack extension at the two interfaces and also to identify a simultaneous crack extension length which results in increasing the pull-out load capacity, increase in energy absorption and increased failure path length but achieved at lowest increase in pull-out deformation thereby proving the effectiveness of two-layer model. Limiting the pull-out deformation is desirable from the point of view of limiting damage.