Quarantine region scheme to mitigate spam attacks in wireless sensor networks

The Quarantine Region Scheme (QRS) is introduced to defend against spam attacks in wireless sensor networks where malicious antinodes frequently generate dummy spam messages to be relayed toward the sink. The aim of the attacker is the exhaustion of the sensor node batteries and the extra delay caused by processing the spam messages. Network-wide message authentication may solve this problem with a cost of cryptographic operations to be performed over all messages. QRS is designed to reduce this cost by applying authentication only whenever and wherever necessary. In QRS, the nodes that detect a nearby spam attack assume themselves to be in a quarantine region. This detection is performed by intermittent authentication checks. Once quarantined, a node continuously applies authentication measures until the spam attack ceases. In the QRS scheme, there is a tradeoff between the resilience against spam attacks and the number of authentications. Our experiments show that, in the worst-case scenario that we considered, a not quarantined node catches 80 percent of the spam messages by authenticating only 50 percent of all messages that it processe

Anterior spinal cord herniation after multilevel anterior cervical corpectomy: A case report

Many complications related to the resection of an ossified posterior longitudinal ligament via the anterior approach have been reported. Postoperative neurological deterioration is one such complication that may appear due to massive anterior spinal cord herniation related to a dural defect following resection of the ossified posterior longitudinal ligament. Specifically, spinal cord herniations have been reported to be associated with posterior approaches, and a large number of theories regarding this association have been offered by various authors. However, anterior spinal cord herniation is extremely rare, and its pathophysiology has not yet been explained. In this case report, we report a male patient who experienced anterior spinal cord herniation following anterior surgery. Spinal cord herniation may develop following the removal of the anterior cervical corpectomy. Therefore, surgeons should be aware of this condition when planning treatments for cervical spondylotic myelopathy via the anterior approach

The Effect of Vascular Graft and Human Umbilical Cord Blood-Derived CD34+ Stem Cell on Peripheral Nerve Healing

AIM: There are many trials concerning peripheral nerve damage causes and treatment options. Unfortunately, nerve damage is still a major problem regarding health, social and economic issues. On this study, we used vascular graft and human cord blood derived stem cells to find an alternative treatment solution to this problem. MATERIAL AND METHODS: We used 21 female Wistar rats on our study. They were anesthetized with ketamine and we studied right hind limbs. On Group 1, we did a full layer cut on the right sciatic nerve. On Group 2, we did a full layer cut on the right sciatic nerve, and we covered synthetic vascular graft on cut area. On Group 3, we did a full layer cut on right sciatic nerve, and we covered the area with stem cell applied vascular graft. RESULTS: At the end of postoperative 8. weeks, we performed EMG on the rats. When we compared healthy and degenerated areas as a result of EMG, we found significant amplitude differences between the groups on healthy areas whereas there was no significant difference on degenerated  areas between the groups. Then we re-opened the operated area again to reveal the sciatic nerve cut area, and we performed electron microscope evaluation. On the stem cell group, we observed that both the axon and the myelin sheet prevented degeneration. CONCLUSION: This study is a first on using synthetic vascular graft and cord blood derived CD34+ cells in peripheral nerve degeneration. On  the  tissues  that  were  examined  with  electron  microscope,  we  observed  that  CD34+  cells  prevented  both  axonal  and  myelin  sheath degeneration. Nerve tissue showed similar results to the control group, and the damage was minimal

Investigation of the Distribution of Fetal Nasal Bone Percentile Values in First-Trimester Fetal Anomaly Screening

INTRODUCTION: We aim to determine the fetal nasal bone length (NBL) percentile values that can be used in the prediction of the fetal anomaly at 11-14 weeks of gestation in a low-risk population. METHODS: Our prospective and cross-sectional study included four hundred and eighty-six singleton pregnancies who applied for the first-trimester aneuploidy screening test at 11-14 weeks of gestation. We excluded pregnant women with fetal structural or chromosomal anomaly, nuchal translucency >3mm, an absent nasal bone, and in utero fetal death. Reference and percentile values of the NBL were calculated separately for 11,12,13,and 14. gestational weeks. RESULTS: Standard NBL measurements were performed in 486 pregnancies according to inclusion and exclusion criteria. Median NBL values were computed for each gestational age (GA), for 11,12,13 and 14. weeks of gestation was found 1.6mm (range=1.1-2.5), 1.8mm (range=1.1-3.0), 2.0mm (range=1.4-3.1), and 2.2mm (range=1.7-2.8), respectively. A positive significant correlation was found between NBL and the crown-rump length (CRL) (NBL (mm) = [0.02xCRL(mm)] + 0.73, r=.483; p<.001). The 5th percentile of NBL for GA was calculated, for 11,12, 13, and 14. weeks of gestation was found 1.2mm,1.4mm,1.5mm, and 1.7mm respectively. DISCUSSION AND CONCLUSION: We revealed the reference value of NBL for each gestational week in the first trimester of the low-risk population. The data obtained in our study can be used in the screening of genetic syndromes, especially Down syndrome, associated with nasal bone hypoplasia. Our reference value of NBL for the first trimester in singleton pregnancy varies from both previous racial and ethnic groups studies, and other Turkish studies

Attitudes and perceptions of elementary teaching through the use of technology in education

WOS: 000257563800025The main aim of the study is to determine the 3(rd) year students' ideas and attitudes towards the utilization of technological tools. The study was conducted with 30 3(rd) year students from Zonguldak Karaelmas University, Eregli Education Faculty, Primary School Education Department. The data collection tool was the "Technology Attitude Scale" of 5 factors and 19 items, developed by Yavuz (2005). Moreover, in order to determine students' ideas on the utilization of technology in education, 5 students were chosen and with semi -structured interview used. While evaluating data's dependent sample t-test was used. When the pre and post test averages of the "Technology Attitude Scale" were compared, a significant difference was statistically observed favoring the posttest (p < 0,05). The results of the study showed that the technology-assisted project studies affected students' attitudes towards the utilization of technology in education positively. The data collected through the interviews enabled the determination of the positive ideas of students on the utilization of technology

Sensor wars: detecting and defending against spam attacks in tactical AdHoc sensor networks

Anti-nodes deployed inside a wireless sensor network can frequently generate dummy data packets that make the nodes relaying them deplete their energy. Especially the nodes closer to the sink fail sooner, because they convey more data packets. This causes the sink to be disconnected from the sensor network. The counter-measures for this type of attacks, namely spam attacks, should consider that the sensor nodes have limited energy, computational power and memory. In this paper, we propose detect and defend against spams (DADS) scheme. In DADS the vicinity of the detected malicious node is notified about the quarantine region, and nodes do not relay unauthenticated messages coming from a node in the quarantine region. Our experiments show that our scheme fits the requirements of the sensor network