A Tutorial on IEEE 802.11ax High Efficiency WLANs Khorov, Evgeny; Kiryanov, Anton; Lyakhov, Andrey ...
IEEE Communications surveys and tutorials,
2019-Firstquarter, Volume:
21, Issue:
1
Journal Article
Peer reviewed
Open access
While celebrating the 21st year since the very first IEEE 802.11 "legacy" 2 Mbit/s wireless local area network standard, the latest Wi-Fi newborn is today reaching the finish line, topping the ...remarkable speed of 10 Gbit/s. IEEE 802.11ax was launched in May 2014 with the goal of enhancing throughput-per-area in high-density scenarios. The first 802.11ax draft versions, namely, D1.0 and D2.0, were released at the end of 2016 and 2017. Focusing on a more mature version D3.0, in this tutorial paper, we help the reader to smoothly enter into the several major 802.11ax breakthroughs, including a brand new orthogonal frequency-division multiple access-based random access approach as well as novel spatial frequency reuse techniques. In addition, this tutorial will highlight selected significant improvements (including physical layer enhancements, multi-user multiple input multiple output extensions, power saving advances, and so on) which make this standard a very significant step forward with respect to its predecessor 802.11ac.
Abstract
The growing integration of software within medical devices introduces the potential for cybersecurity threats. How significant is this risk, and to what extent are citizens currently ...exposed? In this study, we adopt a new data-gathering methodology using datasets provided in Open Contracting Data Standard (OCDS). This allowed us to perform an extensive analysis across over 36 countries within a 12-year range, searching 92 million public administration purchase records for potentially vulnerable medical devices. The findings reveal a concerning landscape wherein numerous medical devices purchased by national health services possessed or still possess 661 distinct vulnerabilities—more than half of which are deemed critical or high-severity. These vulnerabilities enable relatively simple attacks to impact data confidentiality, integrity, and accessibility severely. Even if patches were applied immediately upon discovery, these vulnerabilities would still result in roughly 3.2 years of system exposure from the time a device is purchased until a software vulnerability is announced, with all classes of devices affected, including high-risk IIB and III devices which accounts for 74% of instances. While a full analysis requires interactivity, this noninvasive methodology enables a large-scale study, emphasizing the need to move faster from the safety to the security of medical devices.
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Code Injection attacks such as SQL Injection and Cross-Site Scripting (XSS) are among the major threats for today's web applications and systems. This paper proposes CODDLE, a deep learning-based ...intrusion detection systems against web-based code injection attacks. CODDLE's main novelty consists in adopting a Convolutional Deep Neural Network and in improving its effectiveness via a tailored pre-processing stage which encodes SQL/XSS-related symbols into type/value pairs. Numerical experiments performed on real-world datasets for both SQL and XSS attacks show that, with an identical training and with a same neural network shape, CODDLE's type/value encoding improves the detection rate from a baseline of about 75% up to 95% accuracy, 99% precision, and a 92% recall value.
To determine whether the administration of histology-tailored neoadjuvant chemotherapy (HT) was superior to the administration of standard anthracycline plus ifosfamide neoadjuvant chemotherapy (A+I) ...in high-risk soft tissue sarcoma (STS) of an extremity or the trunk wall.
This was a randomized, open-label, phase III trial. Patients had localized high-risk STS (grade 3; size, ≥ 5 cm) of an extremity or trunk wall, belonging to one of the following five histologic subtypes: high-grade myxoid liposarcoma (HG-MLPS); leiomyosarcoma (LMS), synovial sarcoma (SS), malignant peripheral nerve sheath tumor (MPNST), and undifferentiated pleomorphic sarcoma (UPS). Patients were randomly assigned in a 1:1 ratio to receive three cycles of A+I or HT. The HT regimens were as follows: trabectedin in HG-MLPS; gemcitabine plus dacarbazine in LMS; high-dose prolonged-infusion ifosfamide in SS; etoposide plus ifosfamide in MPNST; and gemcitabine plus docetaxel in UPS. Primary and secondary end points were disease-free survival (DFS) and overall survival (OS), estimated using the Kaplan-Meier method and compared using Cox models adjusted for treatment and stratification factors. The study is registered at ClinicalTrials.gov (identifier NCT01710176).
Between May 2011 and May 2016, 287 patients (UPS: n = 97 33.8%; HG-MLPS: n = 65 22.6%; SS: n = 70 24.4%; MPNST: n = 27 9.4%; and LMS: n = 28 9.8%) were randomly assigned to either A+I or HT. At the final analysis, with a median follow-up of 52 months, the projected DFS and OS probabilities were 0.55 and 0.47 (log-rank
= .323) and 0.76 and 0.66 (log-rank
= .018) at 60 months in the A+I arm and HT arm, respectively. No treatment-related deaths were observed.
In a population of patients with localized high-risk STS, HT was not associated with a better DFS or OS, suggesting that A+I should remain the regimen to choose whenever neoadjuvant chemotherapy is used in patients with high-risk STS.
Analytical modeling of the 802.11e enhanced distributed channel access (EDCA) mechanism is today a fairly mature research area, considering the very large number of papers that have appeared in the ...literature. However, most work in this area models the EDCA operation through per-slot statistics, namely probability of transmission and collisions referred to ¿slots.¿ In so doing, they still share a methodology originally proposed for the 802.11 Distributed Coordination Function (DCF), although they do extend it by considering differentiated transmission/collision probabilities over different slots. We aim to show that it is possible to devise 802.11e models that do not rely on per-slot statistics. To this purpose, we introduce and describe a novel modeling methodology that does not use per-slot transmission/collision probabilities, but relies on the fixed-point computation of the whole (residual) backoff counter distribution occurring after a generic transmission attempt. The proposed approach achieves high accuracy in describing the channel access operations, not only in terms of throughput and delay performance, but also in terms of low-level performance metrics.
The scientific literature peer review workflow is under strain because of the constant growth of submission volume. One response to this is to make initial screening of submissions less time ...intensive. Reducing screening and review time would save millions of working hours and potentially boost academic productivity. Many platforms have already started to use automated screening tools, to prevent plagiarism and failure to respect format requirements. Some tools even attempt to flag the quality of a study or summarise its content, to reduce reviewers’ load. The recent advances in artificial intelligence (AI) create the potential for (semi) automated peer review systems, where potentially low-quality or controversial studies could be flagged, and reviewer-document matching could be performed in an automated manner. However, there are ethical concerns, which arise from such approaches, particularly associated with bias and the extent to which AI systems may replicate bias. Our main goal in this study is to discuss the potential, pitfalls, and uncertainties of the use of AI to approximate or assist human decisions in the quality assurance and peer-review process associated with research outputs. We design an AI tool and train it with 3300 papers from three conferences, together with their reviews evaluations. We then test the ability of the AI in predicting the review score of a new, unobserved manuscript, only using its textual content. We show that such techniques can reveal correlations between the decision process and other quality proxy measures, uncovering potential biases of the review process. Finally, we discuss the opportunities, but also the potential unintended consequences of these techniques in terms of algorithmic bias and ethical concerns.
Background
The value of neoadjuvant chemotherapy in soft tissue sarcoma (STS) is not completely understood. This study investigated the benefit of neoadjuvant chemotherapy according to prognostic ...stratification based on the Sarculator nomogram for STS.
Methods
This study analyzed data from ISG‐STS 1001, a randomized study that tested 3 cycles of neoadjuvant anthracycline plus ifosfamide (AI) or histology‐tailored (HT) chemotherapy in adult patients with STS. The 10‐year predicted overall survival (pr‐OS) was estimated with the Sarculator and was stratified into higher (10‐year pr‐OS < 60%) and lower risk subgroups (10‐year pr‐OS ≥ 60%).
Results
The median pr‐OS was 0.63 (interquartile range IQR, 0.51‐0.72) for the entire study population, 0.62 (IQR, 0.51‐0.70) for the AI arm, and 0.64 (IQR, 0.51‐0.73) for the HT arm. Three‐ and 5‐year overall survival (OS) were 0.86 (95% confidence interval CI, 0.82‐0.93) and 0.81 (95% CI, 0.71‐0.86) in lower risk patients and 0.69 (95% CI, 0.70‐0.85) and 0.59 (95% CI, 0.51‐0.72) in the higher risk patients (log‐rank test, P = .004). In higher risk patients, the 3‐ and 5‐year Sarculator‐predicted and study‐observed OS rates were 0.68 and 0.58, respectively, and 0.85 and 0.66, respectively, in the AI arm (P = .04); the corresponding figures in the HT arm were 0.69 and 0.60, respectively, and 0.69 and 0.55, respectively (P > .99). In lower risk patients, the 3‐ and 5‐year Sarculator‐predicted and study‐observed OS rates were 0.85 and 0.80, respectively, and 0.89 and 0.82, respectively, in the AI arm (P = .507); the corresponding figures in the HT arm were 0.87 and 0.81, respectively, and 0.86 and 0.74, respectively (P = .105).
Conclusions
High‐risk patients treated with AI performed better than predicted, and this adds to the evidence for the efficacy of neoadjuvant AI in STS.
Lay Summary
People affected by soft tissue sarcomas of the extremities and trunk wall are at some risk of developing metastasis after surgery.
Preoperative or postoperative chemotherapy has been tested in clinical trials to reduce the chances of distant metastasis. However, study findings have not been conclusive.
This study stratified the risk of metastasis for people affected by sarcomas who were included in a clinical trial testing neoadjuvant chemotherapy. Exploiting the prognostic nomogram Sarculator, it found a benefit for chemotherapy when the predicted risk, based on patient and tumor characteristics, was high.
This analysis of the ISG‐STS 1001 trial, which compares anthracycline plus ifosfamide and histology‐tailored chemotherapy in 5 high‐risk soft tissue sarcomas of the extremities and trunk wall, supports the Sarculator nomogram for stratifying patient risk in clinical practice and in clinical trials that will investigate perioperative therapies for soft tissue sarcomas.
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Modern malware poses a severe threat to cybersecurity, continually evolving in sophistication. To combat this threat, researchers and security professionals continuously explore advanced techniques ...for malware detection and analysis. Dynamic analysis, a prevalent approach, offers advantages over static analysis by enabling observation of runtime behavior and detecting obfuscated or encrypted code used to evade detection. However, executing programs within a controlled environment can be resource-intensive, often necessitating compromises, such as limiting sandboxing to an initial period. In our article, we propose an alternative method for dynamic executable analysis: examining the presence of malicious signatures within executable virtual pages precisely when their current content, including any updates over time, is accessed for instruction fetching. Our solution, named JITScanner, is developed as a Linux-oriented package built upon a Loadable Kernel Module (LKM). It integrates a user-level component that communicates efficiently with the LKM using scalable multi-processor/core technology. JITScanner’s effectiveness in detecting malware programs and its minimal intrusion in normal runtime scenarios have been extensively tested, with the experiment results detailed in this article. These experiments affirm the viability of our approach, showcasing JITScanner’s capability to effectively identify malware while minimizing runtime overhead.
Code injection is one of the top cyber security attack vectors in the modern world. To overcome the limitations of conventional signature-based detection techniques, and to complement them when ...appropriate, multiple machine learning approaches have been proposed. While analysing these approaches, the surveys focus predominantly on the general intrusion detection, which can be further applied to specific vulnerabilities. In addition, among the machine learning steps, data preprocessing, being highly critical in the data analysis process, appears to be the least researched in the context of Network Intrusion Detection, namely in code injection. The goal of this survey is to fill in the gap through analysing and classifying the existing machine learning techniques applied to the code injection attack detection, with special attention to Deep Learning. Our analysis reveals that the way the input data is preprocessed considerably impacts the performance and attack detection rate. The proposed full preprocessing cycle demonstrates how various machine-learning-based approaches for detection of code injection attacks take advantage of different input data preprocessing techniques. The most used machine learning methods and preprocessing stages have been also identified.
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Introduction
Epithelioid sarcoma (ES) has a tendency to locally recur, spread proximally, and metastasize, in particular to lymphnodes and lungs. The aim of this report is to study the role of ...surgery and the extent of margins required for optimal management of patients with localized epithelioid sarcoma of the extremities.
Material and Methods
We retrospectively evaluated 77 patients affected by ES of the extremities treated at two different Institutions.
Results
Twenty‐two patients had metastasis at diagnosis. Estimated survival was 65.5% at 5 years and 50.9% at 10 years, with a better prognosis in patients with localized disease at diagnosis (P < 0.001). Among patients with localized disease, a significantly better survival was found in patients with primary tumors in which radical surgical margins were achieved (P = 0.043). Among 47 patients presenting with primary tumors, local recurrence‐free rate was 72.9% at 5 years, and 61.9% at 10 years, with a better local control achieved in patients with radical margins were achieved (P = 0.026).
Discussion
We believe that the best approach to improve both local control and survival is to aim for radical margins in patients with primary tumors. Therefore, the best chance for cure is if the first treatment is the right treatment, which we believe to be radical margins.
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