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Blackhole (BH) attacks are among the most significant threats in mobile ad-hoc networks. A BH is a security attack in which a malicious node absorbs data packets and sends fake routing information to neighboring nodes. BH attacks have been widely studied. However, existing defense methods wrongfully assume that BH attacks cannot overcome the most common defense approaches. A new wave of BH attacks is known as smart BH attacks. In this study, we used a highly aggressive type of BH attack that can predict sequence numbers to overcome traditional detection methods that set a threshold to sequence numbers. To protect the network from this type of BH attack, we propose a collaborative defense method that uses local information collected from neighboring nodes. We evaluated the performance of our defense method against a smart BH attack and a collaborative attack that uses the collaboration of another malicious node. Our results show that the proposed method successfully detects and contains these threats to some degree. Consequently, the smart BH attack success rate decreases.

Major bleeding associated with sagittal split ramus osteotomy (SSRO) involves vessels such as the inferior alveolar, facial, and maxillary arteries and veins, and the retromandibular vein (RMV). The present study aimed to clarify and classify the three-dimensional variations in RMV position and course direction in relation to the mandible. Specimens comprised a total of 15 scientific cadavers, and the relationship between RMV and the mandible lateral and posterior views was observed. We identified 3 patterns on the lateral view, the mean distance between the RMV and the posterior border of the ramus was 3.9 mm at the height of the lingula. A total of five course patterns were identified on the posterior view. In no course pattern, the RMV inferior to the lingula was lateral to its position superior to the lingual. The present findings suggest that it may be possible to predict correlations with intraoperative bleeding risk. Further study is planned using contrast computed tomography in patients with jaw deformity for skeletal classification.

The IEEE 802.15.4 is a popular standard used in wireless sensor networks (WSNs) and the Internet of Things (IoT) applications. In these networks, devices are organized into groups formally known as personal area networks (PAN) which require a bootstrap procedure to become operational. Bootstrap plays a key role in the initialization and maintenance of these networks. For this reason, this work presents our implementation and performance analysis for the ns-3 network simulator. Specifically, this bootstrap implementation includes the support of three types of scanning mechanisms (energy scan, passive scan, and active scan) and the complete classic association mechanism described by the standard. Both of these mechanisms can be used independently by higher layers protocols to support network initialization, network joining, and maintenance tasks. Performance evaluation is conducted in total network association time and packet overhead terms. Our source code is documented and publicly available in the latest ns-3 official release.

The IEEE 802.15.4 is a standard that has grown in popularity since its introduction in 2003. The IEEE 802.15.4 standard describes the necessary PHY (layer 1) and MAC (layer 2) abstractions to support networks with low data rates and low power consumption requirements. Such characteristics make it a popular choice for wireless sensor networks (WSNs). Despite the popularity of IEEE 802.15.4, there are only a few available simulations that often lack source code documentation and, more importantly, do not describe in detail the simulated components. In this study, we developed a simulation that extends the capabilities of the LR-WPAN (IEEE 802.15.4) ns-3 simulator module to support the beacon-enabled mode, which provides the energy-saving features of the standard. Some of the characteristics provided in our implementation include: (1) Active and inactive periods; (2) Slotted CSMA-CA with data packet deferring transmission support; (3) Bidirectional direct transmissions; (4) Realistic packet representation. In our evaluations, we discuss some of the issues that create performance discrepancies among existing IEEE 802.15.4 simulations and practical implementations. Furthermore, we present our results using the beacon-enabled mode. Our code has been reviewed, documented, and integrated with the latest official release of the ns-3 simulator.

In recent years, vehicle tracking using a vehicular ad hoc network (VANET), where vehicular connectivity is supported by both vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications, has attracted considerable attention. Vehicle tracking is useful in a variety of applications, such as traffic management, collecting vehicle trajectory data, stolen car recovery and in the pursuit of an illegal runaway vehicle. Some of these applications require real-time and uninterrupted vehicle tracking. The unpredictable movement of the target vehicle and uneven spatial distribution of vehicles that participate in the tracking process make real-time and uninterrupted vehicle tracking challenging.In this paper, we propose a cooperative method to track target vehicles in real time by using VANETs. In our method, vehicles and road side units (RSUs) cooperate to track the location of target vehicles. In order to achieve the uninterrupted tracking of a target vehicle, a tracker broadcasts a handoff request message to its surrounding vehicles before losing the target. We implement the proposed method in a network simulator and evaluate its effectiveness and performance. Our simulation results show that the proposed method can achieve efficient and uninterrupted real-time vehicle tracking.

For 15 years, the popular IEEE 802.15.4 standard has served as de facto standard for applications with low latency and small energy consumption requirements. During this time, it has evolved and dramatically extend its original purpose. With thousand of possible parameters and combinations, its objectives are not as clear as they were when it was first introduced. In this paper, we present a concise and chronological description of the standard highlighting the main features introduced by each one of its revisions as well as a notion of its usage. A compendium of this kind can be valuable to researchers working on implementations and improvements and to users seeking a general reference. This is relevant now more than ever because the standard must coexist with hundreds of other standards that are also constantly evolving. As presented in this document and despite its popularity and importance, there are very few capable IEEE 802.15.4 simulators and these are often outdated and incomplete. The aim of this paper is to provide a quick reference but also present the evolution of the standard and its future directions. Similarly, we hope that this study fosters the creation of new implementations, particularly new simulations modules.

In recent years, wireless sensor networks (WSN) have evolved from single-hop networks to complex multi-hop (mesh) networks. WSN nodes are finite resources that must be replaced periodically, either due to damage or because they have depleted their energy. When multiple nodes fail simultaneously, a replacement priority must be used to replace the most significant nodes first. In this paper, we propose a method to calculate a node replacement priority in multiple situations. Our method is designed to be used in WSN. Unlike traditional networks, WSN values their nodes not only on the amount of data they collect but also the size of the area their sensors can cover. Traditional node replacement approaches rarely consider these factors. Our method uses the sensor's coverage area to assign a priority to each node and determine its relevance in the network. This priority assignation considers not only the sensor coverage area of a single node, but also the aggregated sensors' coverage areas of multiple nodes. The proposed method is particularly useful when a multinode failure occurs (e.g. natural disasters) or when diagnostic and maintenance tasks are necessary.

For several years, the IEEE 802.15.4 standard has been the backbone of applications with low latency and small energy consumption requirements. Its popularity has made it the de facto standard for this type of network communication, and the IEEE 802.15.4 standard will continue to play an important role in the Internet of Things (IoT) revolution. The standard has existed for the past 15 years and its applications have evolved over the years. In this paper, we present a concise and chronological description of the standard highlighting each feature that has been introduced over the years. A compendium of this kind can be valuable to researchers working on implementations and improvements and to users seeking a general reference. This is relevant now more than ever because the standard must coexist with hundreds of other standards that are also constantly evolving. As presented in this document and despite its popularity and importance, there are very few capable IEEE 802.15.4 simulators and these are often outdated and incomplete. The aim of this paper is to provide a quick reference but also present the evolution of the standard and its future directions. Similarly, we hope that this study fosters the creation of new implementations, particularly new simulations modules.

Hypophosphatasia (HPP) is an inherited skeletal and dental disease caused by loss-of-function mutations in the gene that encodes tissue-nonspecific alkaline phosphatase (TNALP). The major symptoms of severe forms of the disease are bone defects, respiratory insufficiency, and epileptic seizures. In 2015, enzyme replacement therapy (ERT) using recombinant bone-targeted TNALP with deca-aspartate (D10) motif was approved to treat pediatric HPP patients in Japan, Canada, and Europe. However, the ERT requires repeated subcutaneous administration of the enzyme because of the short half-life in serum. In the present study, we evaluated the feasibility of neonatal ex vivo gene therapy in TNALP knockout (Akp2(-/-)) HPP mice using lentivirally transduced bone marrow cells (BMC) expressing bone-targeted TNALP in which a D10 sequence was linked to the C-terminus of soluble TNALP (TNALP-D10). The Akp2(-/-) mice usually die within 20 days because of growth failure, epileptic seizures, and hypomineralization. However, an intravenous transplantation of BMC expressing TNALP-D10 (ALP-BMC) into neonatal Akp2(-/-) mice prolonged survival of the mice with improved bone mineralization compared with untransduced BMC-transplanted Akp2(-/-) mice. The treated Akp2(-/-) mice were normal in appearance and experienced no seizures during the experimental period. The lentivirally transduced BMC were efficiently engrafted in the recipient mice and supplied TNALP-D10 continuously at a therapeutic level for at least 3 months. Moreover, TNALP-D10 overexpression did not affect multilineage reconstitution in the recipient mice. The plasma ALP activity was sustained at high levels in the treated mice, and tissue ALP activity was selectively detected on bone surfaces, not in the kidneys or other organs. No ectopic calcification was observed in the ALP-BMC-treated mice. These results indicate that lentivirally transduced BMC can serve as a reservoir for stem cell-based ERT to rescue the Akp2(-/-) phenotype. Neonatal ex vivo gene therapy thus appears to be a possible treatment option for treating severe HPP.

Over the past decade, Vehicular Ad Hoc Networks (VANETs) are increasingly gaining attention for their applicability in safe driving support systems. There are a variety of safety and route planning applications using VANETs such as emergency accidents warning, intersections warning, and road congestion warning applications. Vehicle visualization is an effective way to support safe driving. Visualized hidden vehicles on navigation maps of in-vehicle display devices can strongly enhance the driver's view field. In this paper, we propose an efficient vehicle visualization system using VANETs. It is a safety and route planning application that includes optimization mechanisms to reduce broadcast packets. We evaluate its visualization performance and the effectiveness of the optimization mechanisms by conducting real-world VANET experiments.

In mobile ad hoc networks (MANETs), when information about the location of the destination node is known, efficient communication can be achieved by using location-based routing protocols. Even in location-based routing protocols, with omnidirectional antennas there is some redundant route discovery by blind flooding of route request packets outside the area between the source and destination. These redundant route discovery propagations can be reduced by using both a scheme of restricted flooding and directional antennas. In this paper, we propose a new location-based routing protocol using both restricted flooding and directional antennas, called Adaptive Location-Aware Routing with Directional Antennas (ALAR-DA). To investigate the performance of ALAR-DA, we compare it with existing location-aware routing protocols. Our simulation results show that ALAR-DA outperforms existing protocols from the standpoints of delay and route discovery traffic.