Should I send now or send later? A decision-theoretic approach to transmission scheduling in sensor networks with mobile sinks

Mobile sinks can significantly extend the lifetime of a sensor network by eliminating the need for expensive hop-by-hop routing. However, a sensor node might not always have a mobile sink in transmission range, or the mobile sink might be so far that the data transmission would be very expensive. In the latter case, the sensor node needs to make a decision whether it should send the data now, or take the risk to wait for a more favorable occasion. Making the right decisions in this transmission scheduling problem has significant impact on the performance and lifetime of the node. In this paper, we investigate the fundamentals of the transmission scheduling problem for sensor networks with mobile sinks. We first develop a dynamic programming-based optimal algorithm for the case when the mobility of the sinks is known in advance. Then, we describe two decision theoretic algorithms which use only probabilistic models learned from the history of interaction with the mobile sinks, and do not require knowledge about their future mobility patterns. The first algorithm uses Markov Decision Processes with states without history information, while the second algorithm encodes some elements of the history into the state. Through a series of experiments, we show that the decision theoretic approaches significantly outperform naive heuristics, and can have a performance close to that of the optimal approach, without requiring an advance knowledge of the mobility

Exposing Vulnerabilities in Mobile Networks: A Mobile Data Consumption Attack

Smartphone carrier companies rely on mobile networks for keeping an accurate record of customer data usage for billing purposes. In this paper, we present a vulnerability that allows an attacker to force the victim's smartphone to consume data through the cellular network by starting the data download on the victim's cell phone without the victim's knowledge. The attack is based on switching the victim's smartphones from the Wi-Fi network to the cellular network while downloading a large data file. This attack has been implemented in real-life scenarios where the test's outcomes demonstrate that the attack is feasible and that mobile networks do not record customer data usage accurately.Comment: 5 pages, 6 figures, presented on IEEE MASS 201

Defense against Sybil attack in the initial deployment stage of vehicular ad hoc network based on roadside unit support

In this paper, we propose two certificate mechanisms for preventing the Sybil attack in a vehicular ad hoc network (VANET): the timestamp series approach and the temporary certificate approach. We focus on an early-stage VANET when the number of smart vehicles is only a small fraction of the vehicles on the road and the only infrastructure components available are the roadside units (RSUs). Our approach does not require a dedicated vehicular public key infrastructure to certify individual vehicles but RSUs are the only components issuing certificates. The vehicles can obtain certificates by simply driving by RSUs, without the need to pre-register at a certificate authority. The timestamp series approach exploits the fact that because of the variance of the movement patterns of the vehicles, it is extremely rare that the two vehicles pass by a series of RSUs at exactly the same time points. The vehicles obtain a series of certificates signed by the RSUs, which certify their passing by at the RSU at a certain time point. By exploiting the spatial and temporal correlation between vehicles and RSUs, we can detect the Sybil attack by checking the similarity of timestamp series. In the temporary certificate-based approach, an RSU issues temporary certificates valid only in a particular area for a limited time. To guarantee that each vehicle is assigned only a single certificate, at the issuance of the first certificate, it is required that the RSU physically authenticate the vehicle. When driving by the subsequent RSUs, however, the certificate can be updated in a chained manner. By guaranteeing that each vehicle is issued a single certificate in a single area, the Sybil attack is prevented. We provide mathematical analysis and simulation for the timestamp series approach. The simulation shows that it works with a small false-positive rate in simple roadway architecture

Cluster Aware Mobility Encounter Dataset Enlargement

The recent emerging fields in data processing and manipulation has facilitated the need for synthetic data generation. This is also valid for mobility encounter dataset generation. Synthetic data generation might be useful to run research-based simulations and also create mobility encounter models. Our approach in this paper is to generate a larger dataset by using a given dataset which includes the clusters of people. Based on the cluster information, we created a framework. Using this framework, we can generate a similar dataset that is statistically similar to the input dataset. We have compared the statistical results of our approach with the real dataset and an encounter mobility model generation technique in the literature. The results showed that the created datasets have similar statistical structure with the given dataset.Comment: 5 pages, 4 figures. In 2019 International Wireless Communications and Mobile Computing Conference (IWCMC), June 201

VBCA: A Virtual Forces Clustering Algorithm for Autonomous Aerial Drone Systems

We consider the positioning problem of aerial drone systems for efficient three-dimensional (3-D) coverage. Our solution draws from molecular geometry, where forces among electron pairs surrounding a central atom arrange their positions. In this paper, we propose a 3-D clustering algorithm for autonomous positioning (VBCA) of aerial drone networks based on virtual forces. These virtual forces induce interactions among drones and structure the system topology. The advantages of our approach are that (1) virtual forces enable drones to self-organize the positioning process and (2) VBCA can be implemented entirely localized. Extensive simulations show that our virtual forces clustering approach produces scalable 3-D topologies exhibiting near-optimal volume coverage. VBCA triggers efficient topology rearrangement for an altering number of nodes, while providing network connectivity to the central drone. We also draw a comparison of volume coverage achieved by VBCA against existing approaches and find VBCA up to 40% more efficient

VBCA: A Virtual Forces Clustering Algorithm for Autonomous Aerial Drone Systems

We consider the positioning problem of aerial drone systems for efficient three-dimensional (3-D) coverage. Our solution draws from molecular geometry, where forces among electron pairs surrounding a central atom arrange their positions. In this paper, we propose a 3-D clustering algorithm for autonomous positioning (VBCA) of aerial drone networks based on virtual forces. These virtual forces induce interactions among drones and structure the system topology. The advantages of our approach are that (1) virtual forces enable drones to self-organize the positioning process and (2) VBCA can be implemented entirely localized. Extensive simulations show that our virtual forces clustering approach produces scalable 3-D topologies exhibiting near-optimal volume coverage. VBCA triggers efficient topology rearrangement for an altering number of nodes, while providing network connectivity to the central drone. We also draw a comparison of volume coverage achieved by VBCA against existing approaches and find VBCA up to 40% more efficient

Greedy path planning for maximizing value of information in underwater sensor networks

Underwater sensor networks (UWSNs) face specific challenges due to the transmission properties in the underwater environment. Radio waves propagate only for short distances under water, and acoustic transmissions have limited data rate and relatively high latency. One of the possible solutions to these challenges involves the use of autonomous underwater vehicles (AUVs) to visit and offload data from the individual sensor nodes. We consider an underwater sensor network visually monitoring an offshore oil platform for hazards such as oil spills from pipes and blowups. To each observation chunk (image or video) we attach a numerical value of information (VoI). This value monotonically decreases in time with a speeed which depends on the urgency of the captured data. An AUV visits different nodes along a specific path and collects data to be transmitted to the customer. Our objective is to develop path planners for the movement of the AUV which maximizes the total VoI collected. We consider three different path planners: the lawn mower path planner (LPP), the greedy planner (GPP) and the random planner (RPP). In a simulation study we compare the total VoI collected by these algorithms and show that the GPP outperforms the other two proposed algorithms on the studied scenarios

Evaluation of the Sterility of PRP Obtained with Multi-bag System (PRPBAG®)

Introduction:The aim of this study is demonstrating the sterility of PRPBAG®, a multi-bag completely closed PRP preparation system different than PRP kits in the market and determining preservability of the sterility of PRP produced with PRPBAG® up to 5 days similar to other platelet products.Methods:We recruited 60 participants for increased statistical significance. 150 mL of whole blood was collected in specially produced PRPBAG®. A double-spin preparation method was used for the samples with a refrigerated centrifuge specially manufactured for PRPBAG®. We started centrifugation within 1 h after collecting blood. In the 1st spin of the centrifugation, whole blood was centrifuged. Erythrocytes precipitated in the first bag because of blood component density, and the supernatant plasma was transferred into the second bag using a manual plasma extractor. The third bag was empty after the first spin. We used a hose-closing device to separate the first bag, which contained erythrocytes, from the other bags. In the second spin of centrifugation, the plasma was centrifuged.Results:PRP product with high-quality was collected in the second bag. We have considered the European guidelines for the preparation, use, and quality assurance of blood components during the whole process. 1 cc of PRP was added into separate pediatric blood culture bottles on days 0, 1, 2, 3, 4, and 5. These samples were sent to the microbiology laboratory and incubated for 5 days. After this incubation period, the blood culture bottles that did not give positive signals were reported as sterile.Conclusion:Currently, PRP is used immediately after preparation. Our study demonstrates that PRP prepared with a closed triple blood bag system PRPBAG® may be used for 5 days if agitated at room temperature. There was not any bacterial growth in any sample after 5 days