A numerical study involving graphical analysis has been carried out to investigate fluid flow and heat transfer between two stationary horizontal plates possessing blocks (which restricts flow). ...Important parameters corresponding to pressure, velocity, temperature, heat transfer coefficient and Nusselt Number have been under the spotlight. Multiple investigations have been undertaken to observe the flow and heat transfer characteristics not only by altering the size of blocks but also by changing the number of blocks. As the blocks reduce the area of flow, following the Continuity equation, reduction of flow area increases the flow velocity and makes the flow turbulent. And the rise of fluid velocity lowers the pressure according to Bernoulli’s principle. Moreover, the presence of blocks creates recirculation of fluid which increases the available time for heat gaining while heat flux is being applied. Blocks contribute to the increase in temperature of the fluid. The higher velocity of fluid causes higher collision among fluid particles. Thus, the heat transfer coefficient and Nusselt Number increase.
Objective Although the prevalence of autism spectrum disorder (ASD) is increasing, appropriate diagnosis and prevention strategies are still lacking. This case–control study was designed to explore ...the association between ASD and the rs1867503 and rs9951150 polymorphisms of the TF and TCF4 genes, respectively. Methods Ninety-six children with ASD and 118 healthy children were recruited and polymerase chain reaction–restriction fragment length polymorphism technique was applied for genotyping. Results The frequencies of the mutant allele G were 48% and 44% for the rs1867503 and rs9951150 polymorphisms, respectively. In our analysis, both TF and TCF4 polymorphisms were associated with an increased risk of developing ASD. AG heterozygotes (OR = 3.18), GG mutant homozygotes (OR = 2.62), AG + GG combined genotypes (OR = 2.98), and G mutant alleles of TF rs1867503 (OR = 1.94) were associated with a significantly elevated risk of ASD. Likewise, AG heterozygotes (OR = 2.92), GG mutant homozygotes (OR = 2.36), AG + GG combined genotypes (OR = 2.72), and G minor alleles of TCF4 rs9951150 (OR = 1.92) were associated with a significantly elevated risk of ASD. Conclusions Our results indicate that TF rs1867503 and TCF4 rs9951150 polymorphisms may be strongly associated with the development of ASD in Bangladeshi children.
Coronavirus disease 2019, i.e. COVID-19 has imposed the public health measure of keeping social distancing for preventing mass transmission of COVID-19. For monitoring the social distancing and ...keeping the trace of transmission, we are obligated to develop various types of digital surveillance systems, which include contact tracing systems and drone-based monitoring systems. Due to the inconvenience of manual labor, traditional contact tracing systems are gradually replaced by the efficient automated contact tracing applications that are developed for smartphones. However, the commencement of automated contact tracing applications introduces the inevitable privacy and security challenges. Nevertheless, unawareness and/or lack of smartphone usage among mass people lead to drone-based monitoring systems. These systems also invite unwelcomed privacy and security challenges. This paper discusses the recently designed and developed digital surveillance system applications with their protocols deployed in several countries around the world. Their privacy and security challenges are discussed as well as analyzed from the viewpoint of privacy acts. Several recommendations are suggested separately for automated contact tracing systems and drone-based monitoring systems, which could further be explored and implemented afterwards to prevent any possible privacy violation and protect an unsuspecting person from any potential cyber attack.
Background: The Ponseti method has become established treatment of choice in the management of clubfoot i.e. congenital talipes equinovarus (CTEV). Tenotomy of Tendo-achillis often is required as ...last step of ponseti method of treatment. This procedural note describes a simple method of doing a percutaneous tenotomy of Tendo-achilles. Methods: In Orthopedics OPD of Dhaka Medical College Hospital, Dhaka, percutaneous needle tenotomy was done in 70 feet of 52 patients from September 2013 to May 2014 by the same orthopedic surgeons for the management of CTEV by Ponseti technique. Results: We have found this technique is very effective than the commonly practiced percutaneous blade tenotomy or open tenotomy. Conclusion: This simple method of tenotomy using a wide bore needle during treatment of clubfoot in children can be a good surgical option. DOI: http://dx.doi.org/10.3329/jdmc.v23i1.22695 J Dhaka Medical College, Vol. 23, No.1, April, 2014, Page 55-59
As the use of Blockchain for digital payments continues to rise in
popularity, it also becomes susceptible to various malicious attacks.
Successfully detecting anomalies within Blockchain ...transactions is essential
for bolstering trust in digital payments. However, the task of anomaly
detection in Blockchain transaction data is challenging due to the infrequent
occurrence of illicit transactions. Although several studies have been
conducted in the field, a limitation persists: the lack of explanations for the
model's predictions. This study seeks to overcome this limitation by
integrating eXplainable Artificial Intelligence (XAI) techniques and anomaly
rules into tree-based ensemble classifiers for detecting anomalous Bitcoin
transactions. The Shapley Additive exPlanation (SHAP) method is employed to
measure the contribution of each feature, and it is compatible with ensemble
models. Moreover, we present rules for interpreting whether a Bitcoin
transaction is anomalous or not. Additionally, we have introduced an
under-sampling algorithm named XGBCLUS, designed to balance anomalous and
non-anomalous transaction data. This algorithm is compared against other
commonly used under-sampling and over-sampling techniques. Finally, the
outcomes of various tree-based single classifiers are compared with those of
stacking and voting ensemble classifiers. Our experimental results demonstrate
that: (i) XGBCLUS enhances TPR and ROC-AUC scores compared to state-of-the-art
under-sampling and over-sampling techniques, and (ii) our proposed ensemble
classifiers outperform traditional single tree-based machine learning
classifiers in terms of accuracy, TPR, and FPR scores.
On blockchain-based anonymized dataset distribution platform Kiyomoto, Shinsaku; Rahman, Mohammad Shahriar; Basu, Anirban
2017 IEEE 15th International Conference on Software Engineering Research, Management and Applications (SERA),
2017-June
Conference Proceeding
Odprti dostop
In this paper, we design a distributed platform for anonymized dataset trading without any centralized trusted third party. The platform consists of peers and consensus-based blockchain mechanism, ...and each peer acts as a data broker, data receiver, or verifier for blockchain in a data transfer transaction. A data broker collects data from data owners under their consent for data trading. The Privacy Policy Manager (PPM) manages the consent information and confirms them on behalf of data owners, when data distribution is requested from data broker. We implement a prototype system of the platform using an open-source blockchain mechanism, Hyperledger Fabric, and provide evaluation results of the prototype system.
RFID tags are heavily constrained in computational and storage capabilities, and raise numerous privacy concerns in everyday life due to their vulnerability to different attacks. Both forward ...security and backward security are required to maintain the privacy of a tag i.e., exposure of a tag's secret key should not reveal the past or future secret keys of the tag. We envisage the need for a formal model for backward security for RFID protocol designs in shared key settings, since the RFID tags are too resource-constrained to support public key settings. However, there has not been much research on backward security for shared key environment since Serge Vaudenay in his Asiacrypt 2007 paper showed that perfect backward security is impossible to achieve without public key settings. We propose a Key-Insulated Mutual Authentication Protocol for shared key environment, KIMAP, which minimizes the damage caused by secret key exposure using insulated keys. Even if a tag's secret key is exposed during an authentication session, forward security and `restricted' backward security of the tag are preserved under our assumptions. The notion of `restricted' backward security is that the adversary misses the protocol transcripts which are needed to update the compromised secret key. Although our definition does not capture perfect backward security, it is still suitable for effective implementation as the tags are highly mobile in practice. We also provide a formal security model of KIMAP. Our scheme is more efficient than previous proposals from the viewpoint of computational requirements.
Privacy preserving RFID (Radio Frequency Identification) authentication has been an active research area in recent years. Both forward security and backward security are required to maintain the ...privacy of a tag, i.e., exposure of a tag's secret key should not reveal the past or future secret keys of the tag. We envisage the need for a formal model for backward security for RFID protocol designs in shared key settings, since the RFID tags are too resource-constrained to support public key settings. However, there has not been much research on backward security for shared key environment since Serge Vaudenay in his Asiacrypt 2007 paper showed that perfect backward security is impossible to achieve without public key settings. We propose a Privacy Preserving RFID Authentication Protocol for shared key environment, APRAP, which minimizes the damage caused by secret key exposure using insulated keys. Even if a tag's secret key is exposed during an authentication session, forward security and 'restricted' backward security of the tag are preserved under our assumptions. The notion of 'restricted' backward security is that the adversary misses the protocol transcripts which are needed to update the compromised secret key. Although our definition does not capture perfect backward security, it is still suitable for effective implementation as the tags are highly mobile in practice. We also provide a formal security model of APRAP. Our scheme is more efficient than previous proposals from the viewpoint of computational requirements.
Security in passive resource-constrained Radio Frequency Identification (RFID) tags is of much interest nowadays. Resistance against illegal tracking, cloning, timing, and replay attacks are ...necessary for a secure RFID authentication scheme. Reader authentication is also necessary to thwart any illegal attempt to read the tags. With an objective to design a secure and low-cost RFID authentication protocol, Gene Tsudik proposed a timestamp-based protocol using symmetric keys, named YA-TRAP*. Although YA-TRAP* achieves its target security properties, it is susceptible to timing attacks, where the timestamp to be sent by the reader to the tag can be freely selected by an adversary. Moreover, in YA-TRAP*, reader authentication is not provided, and a tag can become inoperative after exceeding its pre-stored threshold timestamp value. In this paper, we propose two mutual RFID authentication protocols that aim to improve YA-TRAP* by preventing timing attack, and by providing reader authentication. Also, a tag is allowed to refresh its pre-stored threshold value in our protocols, so that it does not become inoperative after exceeding the threshold. Our protocols also achieve other security properties like forward security, resistance against cloning, replay, and tracking attacks. Moreover, the computation and communication costs are kept as low as possible for the tags. It is important to keep the communication cost as low as possible when many tags are authenticated in batch-mode. By introducing aggregate function for the reader-to-server communication, the communication cost is reduced. We also discuss different possible applications of our protocols. Our protocols thus capture more security properties and more efficiency than YA-TRAP*. Finally, we show that our protocols can be implemented using the current standard low-cost RFID infrastructures.
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