829 research outputs found
The SARS-unique domain (SUD) of SARS coronavirus contains two macrodomains that bind G-quadruplexes.
No full textSince the outbreak of severe acute respiratory syndrome (SARS) in 2003, the three-dimensional structures of several of the replicase/transcriptase components of SARS coronavirus (SARS-CoV), the non-structural proteins (Nsps), have been determined. However, within the large Nsp3 (1922 amino-acid residues), the structure and function of the so-called SARS-unique domain (SUD) have remained elusive. SUD occurs only in SARS-CoV and the highly related viruses found in certain bats, but is absent from all other coronaviruses. Therefore, it has been speculated that it may be involved in the extreme pathogenicity of SARS-CoV, compared to other coronaviruses, most of which cause only mild infections in humans. In order to help elucidate the function of the SUD, we have determined crystal structures of fragment 389-652 ("SUD(core)") of Nsp3, which comprises 264 of the 338 residues of the domain. Both the monoclinic and triclinic crystal forms (2.2 and 2.8 A resolution, respectively) revealed that SUD(core) forms a homodimer. Each monomer consists of two subdomains, SUD-N and SUD-M, with a macrodomain fold similar to the SARS-CoV X-domain. However, in contrast to the latter, SUD fails to bind ADP-ribose, as determined by zone-interference gel electrophoresis. Instead, the entire SUD(core) as well as its individual subdomains interact with oligonucleotides known to form G-quadruplexes. This includes oligodeoxy- as well as oligoribonucleotides. Mutations of selected lysine residues on the surface of the SUD-N subdomain lead to reduction of G-quadruplex binding, whereas mutations in the SUD-M subdomain abolish it. As there is no evidence for Nsp3 entering the nucleus of the host cell, the SARS-CoV genomic RNA or host-cell mRNA containing long G-stretches may be targets of SUD. The SARS-CoV genome is devoid of G-stretches longer than 5-6 nucleotides, but more extended G-stretches are found in the 3'-nontranslated regions of mRNAs coding for certain host-cell proteins involved in apoptosis or signal transduction, and have been shown to bind to SUD in vitro. Therefore, SUD may be involved in controlling the host cell's response to the viral infection. Possible interference with poly(ADP-ribose) polymerase-like domains is also discussed
Contactless smart card as a cache for geocaching
No full textV článku je posuzována možnost použít bezkontaktní mikropočítačovou kartu jako skrýš pro geokešing. Geokešing je rekreační venkovní aktivita, jejíž účastníci hledají na základě zeměpisných souřadnic skryté krabičky neboli skrýše. Nevýhodami stávajícího stavu je možnost účastníků podvádět a potřeba údržby skrýší. A pak zde ještě existuje problém, kdy nepoučená veřejnost při náhodném objevu skrýše ji interpretuje jako nástražné výbušné zařízení. V článku je navržen koncept možného řešení výše uvedených problémů a to cestou náhrady krabiček běžnými bezdrátovými mikropočítačovými kartami. Rovněž je zde navržena potřebná infrastruktura a i kryptografický protokol potřebný pro bezpečnou komunikaci mezi smartfonem účastníka a skrýší.The article considers the possibility of using a contactless smart card as a cache for geocaching. Geocaching is a recreational outdoor activity in which participants search for caches based on geographical coordinates. The disadvantages of the current situation are the possibility for the participants to cheat and the need to mainten of caches. And then also there is the problem when an uninformed public interpret caches as dangerous or explosive devices. The article proposes a concept of a possible solution to the above problems by replacing the caches with common wireless smart cards. The necessary infrastructure is also designed in the article, as well as the cryptographic protocol needed for a secure communication between the participant's smartphone and the smart card
A Framework for Smart Home Services with Secure and QoS-aware Communications
No full textThe scenario of smart home services will be discussed with regard to two important aspects: the quality of service problem for the in-house communication and the need for a security scheme for the whole system. We focus on an installation with smart computers in each flat interconnected using a switched Ethernet network. These smart devices are responsible for performing local services, user control and operate as a gateway for the different types of sensor and actor networks installed at each flat. We propose a QoS scheme to prevent congestion situation for the Ethernet network which is applicable to currently available cost-sensitive hardware. Furthermore, the whole system, all communication channels, user data and the access to the framework are secured by our proposed security architecture. Finally, we will present the latest improvements on Ethernet network standards, the ongoing work on this topics and our next steps for future work
Risks of Offline Verify PIN on Contactless Cards
No full textContactless card payments are being introduced around the world al- lowing customers to use a card to pay for small purchases by simply placing the card onto the Point of Sale terminal. Contactless transactions do not require veri- fication of the cardholder’s PIN. However our research has found the redundant verify PIN functionality is present on the most commonly issued contactless credit and debit cards currently in circulation in the UK. This paper presents a plausible attack scenario which exploits contactless verify PIN to give unlimited attempts to guess the cardholder’s PIN without their knowledge. It also gives experimental data to demonstrate the practical viability of the attack as well as references to support our argument that contactless verify PIN is redundant functionality which compromises the security of payment cards and the cardholder
On a Dirichlet problem for composite type equation
No full textО.С. Зикиров, Национальный университет Узбекистана, Ташкент, Узбекистан
E-mail: [email protected]. O.S. Zikirov,
National University of Uzbekistan, Tashkent, Uzbekistan
E-mail: [email protected]Исследуется краевая задача для класса уравнений третьего порядка составного типа с эллиптическим оператором в главной части. Доказаны теоремы существования и единственности классического решения для рассматриваемых задач. Доказательство основано на энергетических неравенствах и на теории интегральных уравнений фредгольмовского типа. The aim of this paper is to prove the existence and uniqueness of smooth solutions to the Dirichlet
type problem for one class of third-order equations that do not belong to any of the classic types. One of
the main classes of non-classical equations is third-order composite type equations, the operator of
which is a composition of first-order hyperbolic operator and an elliptic operator in the main part. A
number of boundary value problems for the model composite type equations with the Laplace operator
were investigated by T.D. Dzhuraev. Many studies have proved the existence of solutions to boundary
value problems upon fulfillment of conditions of the convexity of area boundary. The method of proof
used in this paper is similar to the method used in the research paper of the author mentioned above. For
the research of composite type linear equations a combination of the method of potentials (Green's function)
and integral identities is applied. The research method is based on reducing the studied problem
with the help of the Green's function to an integral equation, the proof of its solubility and thus - the
proof of the solvability of original problem.
Upon fulfillment of certain conditions on given functions, a third-order equation reduces to a
second-order equation of elliptic type with an unknown right-hand side and the boundary function. With
the help of Green's functions for elliptic equations, the studied problem is reduced to a second-order
equivalent integral equation, the solvability follows from Fredholm alternative and the theorem of uniqueness
of the solution of the original problem
K-loops: Loop Transformations for Reconfigurable Architectures
No full textThe focus of this dissertation is on kernel loops (K-loops), which are loop nests that contain hardware mapped kernels in the loop body. In this thesis, we propose methods for improving the performance of such K-loops, by using standard loop transformations for exposing and exploiting the coarse grain loop level parallelism. We target a reconfigurable architecture that is a heterogeneous system consisting of a general purpose processor and a field programmable gate array (FPGA). Research projects targeting reconfigurable architectures are trying to give answers to several problems: how to partition the application -- decide which parts to be accelerated on the FPGA, how to optimize these parts (the kernels), what is the performance gain. However, only few try to exploit the coarse grain loop level parallelism. This work goes towards automatically deciding the number of kernel instances to place into the reconfigurable hardware, in a flexible way that can balance between area and performance. In this dissertation, we propose a general framework that helps determine the optimal degree of parallelism for each hardware mapped kernel within a K-loop, taking into account area, memory size and bandwidth, and performance considerations. In the future it can also take into account power. Furthermore, we present algorithms and mathematical models for several loop transformations in the context of K-loops. The algorithms are used to determine the best degree of parallelism for a given K-loop, while the mathematical models are used to determine the corresponding performance improvement. The algorithms are validated with experimental results. The loop transformations that we analyze in this thesis are loop unrolling, loop shifting, K-pipelining, loop distribution, and loop skewing. An algorithm that decides which transformations to use for a given K-loop is also provided. Finally, we also present an analysis of possible situations and justifications of when and why the loop transformations have or have not a significant impact on the K-loop performance.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
Facility Management van de Universiteit van Suriname
No full textVoor de Universiteit van Suriname moest een informatiesysteem opgezet worden om de faciliteiten aldaar te beheren. Hiervoor is gekeken naar de huidige manier van werken en de beschikbare technologieën, waarna het systeem ontworpen en geïmplementeerd is. Hierbij is de nadruk gelegd op de onderhoudbaarheid en mogelijkheid tot verdere ontwikkeling van dit systeem.Software TechnologyElectrical Engineering, Mathematics and Computer Scienc
Digital health systems: SMART-system for remote support of hybrid E-rehabilitation services and activities
No full textThe top-priority challenges were faced by the medical rehabilitation system in Ukraine. Particularly important tasks include, first of all, the rehabilitation of patients who have recovered from COVID-19 disease and people with Combat stress reaction. This fact is well understood both by the society and the leadership of the Ministry of Health of Ukraine, which is creating a special working group on this problem. Ukraine has a system of medical and prophylactic institutions designed for psychological and physical rehabilitation of military personnel; these use modern rehabilitation technologies. However, long-term rehabilitation in such centers is not available to everyone. Therefore, the use of telerehabilitation technology for patients with post-traumatic stress disorder and similar disorders in com- bination with a means of objective control of the functional state is extremely important. One of the most effective solutions in medical rehabilitation assistance is remote patient / person-centered rehabilitation. Rehabilitation also needs effective methods for the "Physical therapist – Patient – Multidisciplinary team" system, including the statistical processing of large volumes of data. Therefore, along with the traditional means of rehabilitation, as part of the "Transdisciplinary intelligent information and analytical system for the rehabilitation processes support in a pandemic (TISP)" in this paper, we introduce and define: the revised and completed basic concepts of the hybrid e-rehabilitation notion and its fundamental foundations; the formalization concept of the new Smart-system for remote support of hybrid e-rehabilitation services and activities; and the methodological foundations for the use of services (UkrVectōrēs and vHealth) of the remote Patient / Person- centered Smart-system. The software implementation of the services of the Smart-system has been developed.Prombles in programming 2022; 3-4: 311-32
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