An interesting case of reruptured endovascularly coiled aneurysm managed with clipping

Endovascular treatment has proven to be effective in the management of intracranial aneurysm, and can achieve permanent occlusion in up to 85% of cases, reducing the bleeding or rebleeding rate. A paradigm shift from microsurgical clipping to endovascular intervention has been observed since the publication of the International Subarachnoid Aneurysm Trial. Aneurysm recurrence after coil embolization remains both a major shortcoming of endovascular treatment and a daunting challenge for neurosurgeons without optimal management strategies.: We present a case report of a patient with history of previously endovascularly coiled and presenting with aneurysmal bleed. Microsurgical clipping is an effective intervention for managing reruptured previously coiled intracranial aneurysm.

Robust, Primitive, and Unsupervised Quality Estimation for Segmentation Ensembles

A multitude of image-based machine learning segmentation and classification algorithms has recently been proposed, offering diagnostic decision support for the identification and characterization of glioma, Covid-19 and many other diseases. Even though these algorithms often outperform human experts in segmentation tasks, their limited reliability, and in particular the inability to detect failure cases, has hindered translation into clinical practice. To address this major shortcoming, we propose an unsupervised quality estimation method for segmentation ensembles. Our primitive solution examines discord in binary segmentation maps to automatically flag segmentation results that are particularly error-prone and therefore require special assessment by human readers. We validate our method both on segmentation of brain glioma in multi-modal magnetic resonance - and of lung lesions in computer tomography images. Additionally, our method provides an adaptive prioritization mechanism to maximize efficacy in use of human expert time by enabling radiologists to focus on the most difficult, yet important cases while maintaining full diagnostic autonomy. Our method offers an intuitive and reliable uncertainty estimation from segmentation ensembles and thereby closes an important gap toward successful translation of automatic segmentation into clinical routine.

Potential Security Vulnerabilities of the IEEE 802.15.4 Standard and a Proposed Solution Against the Dissociation Process

Many different networks that rely on short-distance wireless technology for their functions utilize the IEEE 802.15.4 Standard, especially in the case of systems that experience a low level of traffic. The networks using this standard are typically based on the Low-Rate Wireless Personal Area Network, herein called the LR-WPAN; this network is used for the provision of both the physical layer, herein referred to as the PHY, and the media access control, herein abbreviated as the MAC. There are four security features in the IEEE 802.15.4 Standard that are designed to ensure the safe and secure transmission of data through the network. Disconnection from the network is managed and controlled by the message authentication code, herein referred to as the MAC, while the coordinator personal area network, herein abbreviated as the PAN, is also able to trigger the disconnection. However, the process of disconnection from the network is one area of vulnerability to denial-of-service attacks, herein referred to as DoS; this highlights a major shortcoming of the IEEE 802.15.4 Standard’s security features. This paper is intended to contribute to the improvement of security for the IEEE network by conducting a specific and in-depth review of available literature as well as conducting an analysis of the disassociation process. In doing so, potential new threats will be highlighted, and this data can be used to improve the security of the IEEE 802.15.4 Standard. Overall, in this paper, the role of the Castalia tool in the OMNET++ environment is analysed and interpreted for these potential new threats. Also, this paper proposes a solution to such threats to improve the security IEEE 802.15.4 disassociation process. Keywords: Disassociation vulnerability of IEEE 802.15.4 Standard, DoS attack, IoT security.

Polygon Number Algorithm for Peak-to-Average Ratio Reduction of Massive 5G Systems Using Modified Partial Transmit Sequence Scheme

The high peak-to-average power ratio (PAPR) of the transmit signal is a major shortcoming of OFDM systems, which results in band radiation and distortion due to the nonlinearity of the high-power amplifier (H.P). To resolve the traditional OFDM high-PAPR issue, where the transmit sequence is designed to avoid similar data from being sent in the same order to reduce PAPR, there are numerous conventional ways for lowering the PAPR for OFDM system, such as selective mapping, tone reservation, block coding, filtering, clipping, and partial transmit sequence (PTS). This study proposes a new method called polygon number algorithm (PN) with conventional partial transmit sequence (C-PTS). This method (PN-PTS) processes the entered data before sending it, taking advantage of the number nonsimilarity according to the geometry of the number to prevent direct sending of similar data via PTS, and thus, this improved the level of PAPR rise in the proposed system. The amount of reduction that can be achieved in PAPR is up to 8 dB by different techniques. The best result obtained was the amount of reduction between the conventional method and the proposed method is 4.5683 where N = 64 . Besides this, there is no transmission of side information (SI), which improves transmission efficiency. Finally, this method is easy in the calculation process and the ciphering and deciphering of data, which adds a few calculations.

Lumped parameter modelling of two-phase ejectors: numerical implications of the equilibrium assumptions

The use of carbon dioxide as refrigerant is attracting a growing attention and is a cutting-edge research topic. In spite of its many advantages, carbon dioxide has a major shortcoming, viz., low critical temperature. Owing to the low critical temperature, carbon dioxide cycles encompass both the sub-critical and the trans-critical operation conditions; the trans-critical operating conditions are characterized by high thermodynamic losses, requiring particular attention in the integrated component/system design criteria. In this perspective, in recent years, ejector technology has been widely recognized as a promising technical solution to support the deployment of carbon dioxide cycles, by reducing throttling losses. Unfortunately, the large variation in system operations as well as the changes in sub-critical and trans-critical operating conditions makes the numerical simulation of carbon dioxide ejector-based system a cutting-edge challenge. This paper contributes to the present day discussion on the validation of lumped parameter models for carbon dioxide ejectors. A model taken from the literature has been tested against literature data and the equilibrium assumptions, underlying the modelling approach have been tested.

New Analytical Model for Swellable Materials

As discussed in Chapter 6, numerical prediction of swelling can be attempted using existing hyperelastic material models available in commercial finite element (FE) packages. However, none of these models can accurately represent the behavior of swelling elastomers. The major shortcoming of currently available swelling models is that they consider Gaussian statistics for mechanical contribution of configuration entropy, which is based on chains having limited extensibility. Some later models (not yet incorporated into commercial FE packages) can give a reasonable account of certain behavior patterns in swelling elastomers, but do not explain other aspects well. One of the new approaches is to treat swelling elastomers as gels. As described earlier, gels are mostly liquid, yet they behave like solids due to a three-dimensional cross-linked network within the liquid. Many authors consider gel as poro-elastic or porous and use Darcy’s law to model the amount of fluid influx. However, a swollen elastomer mostly consists of the solvent. When an external load is applied, maximum resistance comes from the solvent molecules as in diffusion. Also, most of the new models are quite complex in concept and formulation, and there is a serious need for a scientifically simpler model.

A Hybrid Between TOA and Lévy Flight Trajectory for Solving Different Cluster Problems

In data analysis applications for extraction of useful knowledge, clustering plays an important role. The major shortcoming of traditional clustering algorithms is exhibiting poor performance in solving complex data cluster problems. This research paper introduces a novel hybrid optimization technique based clustering approach. This paper is designed with two main objectives: designing efficient function optimization algorithm and developing advanced data clustering approach. In achieving the first objective, the standard TOA is first enhanced by hybridizing with Lévy flight trajectory and benchmarked on 23 functions. A new clustering approach is developed by conjoining k-means algorithm and Lévy flight TOA. Tested the numerical complexity of the proposed novel clustering approach on 10 UCI clustering datasets and 4 web document cluster problems. Conducted several simulation experiments and done an analysis of the results. The obtained graphical and statistical analysis reveals that the proposed novel clustering approach yields better quality clusters.

A hybrid between TOA and levy flight trajectory for solving different cluster problems [iccicc18 #107]

In data analysis applications for extraction of useful knowledge, clustering plays an important role. The major shortcoming of traditional clustering algorithms is exhibiting poor performance in solving complex data cluster problems. This research paper introduces a novel hybrid optimization technique based clustering approach. This paper is designed with two main objectives: designing efficient function optimization algorithm and developing advanced data clustering approach. In achieving the first objective, the standard TOA is first enhanced by hybridizing with Lévy flight trajectory and benchmarked on 23 functions. A new clustering approach is developed by conjoining k-means algorithm and Lévy flight TOA. Tested the numerical complexity of the proposed novel clustering approach on 10 UCI clustering datasets and 4 web document cluster problems. Conducted several simulation experiments and done an analysis of the results. The obtained graphical and statistical analysis reveals that the proposed novel clustering approach yields better quality clusters.

Towards Chloride-Free Organic Electrolytes for Rechargeable Aluminum Batteries

The corrosivity of chloride-based electrolytes is a major shortcoming in the practical realization of rechargeable aluminum batteries. Herein, the effect of Cl- on Al speciation and electrochemistry in tetrahydrofuran was measured by employing theoretical and experimental approaches for three systems: Al(OTF)3/THF, Al(OTF)3 plus LiCl in THF, and AlCl3/THF. The high consistency between measured and computed spectroscopic aspects associated with Al(OTF)3/THF electrolyte provided both a rationale for understanding Al complex-ion formation in a Cl- free environment and an approach for examining the effect of Cl- on Al speciation. Room-temperature Al plating was achieved from dilute solutions ([Al] = 0.1M) at potentials ≥ 0V (vs. Al⁄Al3+). Cl- is found to enable facile Al plating and SEM reveals that Al is electrochemically deposited as nanocrystalline grains.

Towards Chloride-Free Organic Electrolytes for Rechargeable Aluminum Batteries

The corrosivity of chloride-based electrolytes is a major shortcoming in the practical realization of rechargeable aluminum batteries. Herein, the effect of Cl- on Al speciation and electrochemistry in tetrahydrofuran was measured by employing theoretical and experimental approaches for three systems: Al(OTF)3/THF, Al(OTF)3 plus LiCl in THF, and AlCl3/THF. The high consistency between measured and computed spectroscopic aspects associated with Al(OTF)3/THF electrolyte provided both a rationale for understanding Al complex-ion formation in a Cl- free environment and an approach for examining the effect of Cl- on Al speciation. Room-temperature Al plating was achieved from dilute solutions ([Al] = 0.1M) at potentials ≥ 0V (vs. Al⁄Al3+). Cl- is found to enable facile Al plating and SEM reveals that Al is electrochemically deposited as nanocrystalline grains.