Analysis of Security Overhead in Broadcast V2V Communications

This paper concerns security issues for broadcast vehicle to vehicle (V2V) messages carrying vehicle status information ((location, heading, speed, etc.). These are often consumed by safety-related applications that e.g. augment situational awareness, issue alerts, recommend courses of action, and even trigger autonomous action. Consequently, the messages need to be both trustworthy and timely. We explore the impact of authenticity and integrity protection mechanisms on message latency using a model based on queuing theory. In conditions of high traffic density such as found in busy city centres, even the latency requirement of 100ms for first generation V2V applications was found to be challenging. Our main objective was to compare the performance overhead of the standard, PKC-based, message authenticity and integrity protection mechanism with that of an alternative scheme, TESLA, which uses symmetric-key cryptography combine with hash chains. This type of scheme has been dismissed in the past due to sup-posed high latency, but we found that in high traffic density conditions it outperformed the PKC-based scheme. without invoking congestion management measures. Perhaps the most significant observation from a security perspective is that denial of service attacks appear very easy to carry out and hard to defend against. This merits attention from the research and practitioner communities and is a topic we intend to address in the future

Spectrum and treatment of bacterial infections in cancer patients with granulocytopenia

Bacterial infections remain a frequent cause of morbidity and mortality in cancer patients with granulocytopenia. In recent years the proportion of patients with gram-positive infections, caused mainly by coagulase-negative staphylococci and viridans streptococci, has increased markedly in many institutions. The precise reasons for this recent change in the epidemiology of infection in cancer patients are as yet not fully ascertained. Although less prevalent, gram-negative infections are still the major threat, since they are associated with higher mortality. What constitutes the optimal empirical antibiotic therapy remains a controversial issue. One should however recognize that the results of one particular study may not be relevant to other institutions where the predominant pathogens and the pattern of antibiotic resistance may be different. In addition, the results of studies using various antibiotic regimens should be compared with caution. However, with these limitations in mind, the results of the most recently published studies support the following recommendations: in patients with nonmicrobiologically documented infections, monotherapy with a third-generation cephalosporin or a carbapenem is a safe alternative to combination therapy. For gram-negative bacteremia, combined therapy with an extended-spectrum beta-lactam antibiotic and an aminoglycoside appears preferable. For gram-positive infections, a specific anti-gram-positive antibiotic is not needed in every patient and can safely be added upon identification of the pathogen in those patients not responding to empirical therapy

Support Care Cancer

OBJECTIVE: Spiritual well-being was found to have some protective effect against end-of life despair in cancer patients. We aimed at assessing the impact of spirituality on the quality of life, depression, and anxiety of Lebanese cancer patients. METHODS: Our observational transversal monocentric study was conducted between January and April 2016 among a convenient sample of 115 Lebanese cancer patients admitted to Hotel-Dieu de France Hospital (HDF), Beirut-Lebanon. In addition to socio-demographic and clinical data, three questionnaires were used: EORTC QLQ-C30 (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, 3rd version), FACIT-Sp-12 (Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being; The 12-item Spiritual Well-Being Scale, 4th version), and HADS (Hospital Anxiety and Depression Scale). Eighteen patients taking anxiolytic and/or antidepressants were not included in the analysis. The remaining 97 patients were analyzed. RESULTS: Better emotional and cognitive functioning was seen in patients with higher meaning, peace, faith, and total FACIT scores. Meaning, peace, and total FACIT scores were also higher among patients with better global health status and quality of life. Anxiety as well as depression was significantly associated to all spiritual well-being factors. CONCLUSION: Spirituality can improve quality of life and decrease the incidence of anxiety and depression in cancer patients. Our results highlight the need to incorporate spiritual care in healthcare systems

A novel queue management policy for delay-tolerant networks

Delay-tolerant networks (DTNs) have attracted increasing attention from governments, academia and industries in recent years. They are designed to provide a communication channel that exploits the inherent mobility of trams, buses and cars. However, the resulting highly dynamic network suffers from frequent disconnections, thereby making node-to-node communications extremely challenging. Researchers have thus proposed many routing/forwarding strategies in order to achieve high delivery ratios and/or low latencies and/or low overheads. Their main idea is to have nodes store and carry information bundles until a forwarding opportunity arises. This, however, creates the following problems. Nodes may have short contacts and/or insufficient buffer space. Consequently, nodes need to determine (i) the delivery order of bundles at each forwarding opportunity and (ii) the bundles that should be dropped when their buffer is full. To this end, we propose an efficient scheduling and drop policy for use under quota-based protocols. In particular, we make use of the encounter rate of nodes and context information such as time to live, number of available replicas and maximum number of forwarded bundle replicas to derive a bundle\u27s priority. Simulation results, over a service quality metric comprising of delivery, delay and overhead, show that the proposed policy achieves up to 80 % improvement when nodes have an infinite buffer and up to 35 % when nodes have a finite buffer over six popular queuing policies: Drop Oldest (DO), Last Input First Output (LIFO), First Input First Output (FIFO), Most FOrwarded first (MOFO), LEast PRobable first (LEPR) and drop bundles with the greatest hop-count (HOP-COUNT)