Enhancing wireless security via optimal cooperative jamming

In this work, we analyze the secrecy rate in a cooperative network, where a source node is assisted by relay nodes via cooperative jamming for delivering a secret message to the destination in the presence of an eavesdropper node. We consider the availability of both full and partial channel state information (CSI), and we take into account average power limitation at the relays as we formulate the rate maximization problem as a primal-dual problem. We derive the closed form solution for the full CSI case, and we show that the optimal solution allows the transmission of only one relay. For the partial CSI case, we define the concept of secrecy outage, where some of packets are intercepted by the eavesdropper, and we derive the secrecy outage probability and throughput in terms of average channel statistics. Due to the high nonlinearity of the secrecy throughput term, we propose a gradient update algorithm for obtaining the optimal power solutions for the partial CSI case. Our simulations demonstrate the gains of cooperative jamming over direct transmission for both full and partial CSI cases, where it is shown that the secrecy rate of the direct transmission is increased significantly, by %20−%80, when CJ is employed with our optimal power assignment algorithm

Accurate non-intrusive residual bandwidth estimation in WMNs

The multi-access scheme of 802.11 wireless networks imposes difficulties in achieving predictable service quality in multi-hop networks. In such networks, the residual capacity of wireless links should be estimated for resource allocation services such as flow admission control. In this paper, we propose an accurate and non-intrusive method to estimate the residual bandwidth of an 802.11 link. Inputs from neighboring network activity measurements and from a basic collision detection mechanism are fed to the analytical model so that the proposed algorithm calculates the maximum allowable traffic level for this link. We evaluate the efficiency of the method via OPNET simulations, and show that the percent estimation error is significantly lower than two other prominent estimation methods, bounded only between 2.5-7.5%. We also demonstrate that flow admission control is successfully achieved in a realistic WMN scenario. Flow control through our proposed algorithm keeps the unsatisfied traffic demand bounded and at a negligibly low level, which is less than an order of magnitude of the other two methods

The efficiency of vancomycin powder and rifampicin for deep surgical site infections in spinal instrumentation surgery

Objective: Infection after spinal surgery always increases the hospital stay in the clinic and can cause serious patient morbidity. This study aimed to show the difference between sprinkling vancomycin powder and washing with rifampicin during debridement surgery in deep infections seen after spinal instrumentation surgeries. Material and methods: This present study was conducted on 179 cases of infection after spinal instrumentation surgeries. The patients were divided into three groups: those receiving topical vancomycin, rifampicin irrigation, and only normal saline irrigation. The preoperative and postoperative CRP levels, hospitalization time, operation length, bone involvement, second operation for infection, impact removal surgeries, and mortality rates have been examined. Results: The CRP decrease on the 5th day was faster in the rifampicin group (p<0.001). On the 30th day, vancomycin and rifampicin decreased CRP values and had a similar effect on hospitalization time but were more effective than the normal saline group (p<0.001). In patients with bone involvement, the rifampicin group was superior to vancomycin and reduced implant removal surgery (p<0.001). Conclusions: Vancomycin powder and rifampicin application during debridement in deep spinal surgical site infections can reduce hospital stays and prevent secondary surgeries. In addition, rifampicin can be effective in infections with bone involvement

Enhancing Wireless Security via Optimal Cooperative Jamming

Abstract In this work, we analyze the secrecy rate in a cooperative network, where a source node is assisted by relay nodes via cooperative jamming for delivering a secret message to the destination in the presence of an eavesdropper node. We consider the availability of both full and partial channel state information (CSI), and we take into account average power limitation at the relays as we formulate the rate maximization problem as a primal-dual problem. We derive the closed form solution for the full CSI case, and we show that the optimal solution allows the transmission of only one relay. For the partial CSI case, we define the concept of secrecy outage, where some of packets are intercepted by the eavesdropper, and we derive the secrecy outage probability and throughput in terms of average channel statistics. Due to the high nonlinearity of the secrecy throughput term, we propose a gradient update algorithm for obtaining the optimal power solutions for the partial CSI case. Our simulations demonstrate the gains of cooperative jamming over direct transmission for both full and partial CSI cases, where it is shown that the secrecy rate of the direct transmission is increased significantly, by %20 − %80, when cooperative jamming is employed with our optimal power assignment algorithm. Index Terms Physical layer security, cooperative jamming, dual algorithm, gradient update algorithm

Dynamic control for cooperative jamming with a non-altruistic node

Cooperative jamming approach in secure communication typically assumes dedicated and/or altruistic jamming nodes, investing their resources for the good of the whole system. In this paper, we consider a cognitive radio network with non-altruistic jamming nodes, from which a source node utilizes jamming service, compensating them with a fraction of its bandwidth for transmission of its data. The nodes only know the distribution of the gains of channels to the eavesdropper. Particularly, the primary node injects confidential data and secondary nodes inject open data at rates in order to maximize global utility function, while keeping data queues stable and meeting a constraint on the secrecy outage probability. The constraint on the secrecy outage probability is met with the help of jamming service obtained from the secondary nodes. Our scheme achieves a utility, arbitrarily close to the maximum achievable utility

Surgeon factor in pediatric supracondylar humerus fractures

The surgeon and the surgical approach of the clinic where the surgeon was trained may have an impact on perioperative outcomes. In this study, among the surgeons with similar surgical experiences, we aimed to investigate the association of open-closed reduction rates, postoperative sagittal, coronal and axial plan deformities, and preference of open surgical approaches to surgeons and the clinics they were trained. We evaluated 90 cases retrospectively who underwent surgery upon diagnosis of Gartland type 3 pediatric supracondylar humerus fractures associated with extension deformity. Those whose surgery was performed after 24 hours, or patients with open fractures, flexion type supracondylar fractures, non-Gartland type 3 supracondylar fractures, fractures with neurovascular deficits, multiple comminuted fractures, pathologic fractures, or additional injury and fractures were not included to the study. All the surgeons who had &gt;5 years of surgical experience as a specialist and &gt;15 of pediatric elbow fracture surgery as an operator (n=12) were numbered between 1 and 12. The clinics of these surgeons were classified from A to F (n=6). Data on patients age, gender, duration of surgery, follow-up time, postoperative sagittal, coronal angulation, postoperative rotational deformity, operation time, rates of open-closed surgery, the surgical approach in those open surgery was performed, the number and characteristics of the pins used were collected to analyze in relation with their assigned surgeons and the clinics they were trained. Among the 90 cases, 54 (59.3%) were male patients. The mean age was 6.21 ± 3.03 years. There was no significant difference between the clinics in terms of sagittal and rotational deformities and open reduction rates (p&gt;0.05). The clinics significantly differed in preference of the side of incisions (medial, lateral, posterior), (p [Med-Science 2020; 9(1.000): 103-8

Haemophilus influenzae serotype e meningitis in an adult

The incidence of Haemophilus influenzae type b (Hib) invasive disease has declined significantly in countries with routine infant Hib immunization. Accordingly, infections caused by other H. influenzae serotypes or by encapsulated H. influenzae strains are of growing interest. H. influenzae serotype e (Hie) is a rare cause of infection. Invasive Hie infections reported in adults are generally in individuals who had previous underlying conditions, in contrast to infections in childhood. We present the first report of Hie meningitis in Turkey. It is of interest that meningitis due to this organism occured as a complication of transsphenoidal hypophysectomy, which to our knowledge has never been documented. Further identification of H. influenzae strains isolated from patients with invasive disease, especially those with predisposing factors and/or who have been vaccinated, is essential

Estimating the channel capacity of multi-hop IEEE 802.11 wireless networks

In IEEE802.11 wireless networks, the residual capacity of the wireless links should be accurately estimated to realize advanced network services such as flow admission control or load balancing. In this paper, we propose an algorithm that estimates the packet delivery failure probability by collecting transmission statistics from nearby nodes, and by using a basic collision detection mechanism. This probability is then used in an analytical model to calculate the maximum allowable traffic needed to reach the saturation condition. We show by simulations that estimation error is within 0.5-2.0%, which is significantly lower than the best performance of prior estimation methods. We also demonstrate that the flow admission control is successfully achieved in a realistic wireless network scenario by the help of accurate link residual bandwidth estimation, where the unsatisfied traffic demand remain bounded at a negligibly low level. A routing algorithm that finds max-min residual bandwidth path between source and destination nodes is also implemented, and simulation results show that the network throughput achieved by this algorithm significantly exceeds that of other popular mesh routing protocols. Finally, we provide test results from the real implementation of our algorithm on 802.11 wireless equipment, which are consistent with the simulations

Device-associated infection rates and bacterial resistance in the intensive care units of a Turkish referral hospital

Objectives: To determine device-associated infection (DAI) rates, and the microbiological and antibiotic resistance profiles of infecting pathogens in our hospital

Effects of simple section of transverse carpal ligament on intercarpal stability in carpal tunnel surgery

The aim was to evaluate effects of simple section of transverse carpal ligament on intercarpal stability by radiological parameters in patients with carpal tunnel syndrome those are refractory to conservative treatment. Patients with suspected diagnosis of carpal tunnel syndrome upon medical history and physical examination underwent neurodiagnostic tests (EMG). All 47 subjects, comprising 39 female and 8 male patients, were operated, followed, and assessed by the same surgical team between January 2014 and May 2015 after written informed consent was obtained. Wrist range of motion and general physical examination findings were recorded at both preoperatively and postoperative week 8. Besides, conventional MRI were obtained at the same time points. Trapeziohamate distance, scaphopisiform distance, scapholunate angle, and carpal angle were measured preoperatively and at 12thweek postoperatively. The mean age of the subjects was 49(range: 36-65).Mean preoperative trapeziohamate distance was measured as 25.2 mm (range:20-33), while postoperative trapeziohamate distance was 26.4 mm (range:22-34), (p=0.031). Mean preoperative scaphopisiform distance was 32 mm (range:23-34), as compared to postoperative scaphopisiform distance being 33.6 mm (range:24- 36) (p=0.001). While mean scapholunate angle was 44&#xb0;(range: 36-60) preoperatively, it was measured as 45.1&#xb0; (range: 33-60) in the postoperative period (p=0.001). Both preoperative and postoperative mean carpal angles was 127&#xb0; (range 118-134 and 119-134, respectively). Simple section of transverse carpal ligament is associated with a significant increase in carpal arch distance. We consider that whether or not increases in intercarpal distances may lead to a degenerative process at the wrist in future warrants further research. [Med-Science 2017; 6(3.000): 410-4