Effective Approaches to Attention-based Neural Machine Translation

An attentional mechanism has lately been used to improve neural machine translation (NMT) by selectively focusing on parts of the source sentence during translation. However, there has been little work exploring useful architectures for attention-based NMT. This paper examines two simple and effective classes of attentional mechanism: a global approach which always attends to all source words and a local one that only looks at a subset of source words at a time. We demonstrate the effectiveness of both approaches over the WMT translation tasks between English and German in both directions. With local attention, we achieve a significant gain of 5.0 BLEU points over non-attentional systems which already incorporate known techniques such as dropout. Our ensemble model using different attention architectures has established a new state-of-the-art result in the WMT'15 English to German translation task with 25.9 BLEU points, an improvement of 1.0 BLEU points over the existing best system backed by NMT and an n-gram reranker.Comment: 11 pages, 7 figures, EMNLP 2015 camera-ready version, more training detail

Streaming Potential and Electro-osmosis Measurements to Characterize Porous Materials

Characterizing the streaming potential and electroosmosis properties of porous media is essential in applying seismoelectric and electroseismic phenomena for oil exploration. Some parameters such as porosity, permeability, formation factor, pore size, the number of pores, and the zeta potential of the samples can be obtained from elementary measurements. We performed streaming potential and electro-osmosis measurements for 6 unconsolidated samples made of spherical polymer particles. To check the validity of the measurements, we also used alternative analysis to determine the average pore size of the samples and, moreover, used a sample made of sand particles to determine the zeta potential

MLAMAN: a novel multi-level authentication model and protocol for preventing wormhole attack in mobile ad hoc network

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Wormhole attack is a serious security issue in Mobile Ad hoc Network where malicious nodes may distort the network topology and obtain valuable information. Many solutions, based on round trip time, packet traversal time, or hop-count, have been proposed to detect wormholes. However, these solutions were only partially successful in dealing with node high-speed mobility, variable tunnel lengths, and fake information by malicious nodes. To address those issues, this paper proposes a novel multi-level authentication model and protocol (MLAMAN) for detecting and preventing wormhole attacks reliably. MLAMAN allows all intermediate nodes to authenticate control packets on a hop-by-hop basis and at three levels: (1) the packet level where the integrity of the packets can be verified, (2) the node membership level where a public key holder-member can be certified, and (3) the neighborhood level where the neighborhood relationship between nodes can be determined. The novelty of the model is that it prevents malicious nodes from joining the network under false information and pretense. It detects wormhole nodes effectively under various scenarios including variable tunnel lengths and speeds of moving nodes. The effectiveness of our approach is confirmed by simulation results through various scenarios

FAPRP: A Machine Learning Approach to Flooding Attacks Prevention Routing Protocol in Mobile Ad Hoc Networks

© 2019 Ngoc T. Luong et al. Request route flooding attack is one of the main challenges in the security of Mobile Ad Hoc Networks (MANETs) as it is easy to initiate and difficult to prevent. A malicious node can launch an attack simply by sending an excessively high number of route request (RREQ) packets or useless data packets to nonexistent destinations. As a result, the network is rendered useless as all its resources are used up to serve this storm of RREQ packets and hence unable to perform its normal routing duty. Most existing research efforts on detecting such a flooding attack use the number of RREQs originated by a node per unit time as the threshold to classify an attacker. These algorithms work to some extent; however, they suffer high misdetection rate and reduce network performance. This paper proposes a new flooding attacks detection algorithm (FADA) for MANETs based on a machine learning approach. The algorithm relies on the route discovery history information of each node to capture similar characteristics and behaviors of nodes belonging to the same class to decide if a node is malicious. The paper also proposes a new flooding attacks prevention routing protocol (FAPRP) by extending the original AODV protocol and integrating FADA algorithm. The performance of the proposed solution is evaluated in terms of successful attack detection ratio, packet delivery ratio, and routing load both in normal and under RREQ attack scenarios using NS2 simulation. The simulation results show that the proposed FAPRP can detect over 99% of RREQ flooding attacks for all scenarios using route discovery frequency vector of sizes larger than 35 and performs better in terms of packet delivery ratio and routing load compared to existing solutions for RREQ flooding attacks

Obstacles to Developing and Implementing Problem-Oriented Policing Projects in Police Agencies

This research examines impediments to problem-solving initiatives within police organizations. A systematic evaluation of a complex problem-oriented policing project in Las Vegas, Nevada, is used to identify obstacles to developing effective crime reduction interventions. This evaluation focuses on the first three steps of the SARA problem-solving process: scanning, analysis, and response. At each stage of the project, interviews are conducted with key project personnel (e.g., area command captains, supervising sergeants, community-oriented policing officers, community partners, residents). Data is also collected through observations at community meetings and ride-alongs with officers assigned to the project. These data are analyzed and common themes are identified. The observed process is evaluated using the theoretical frameworks that form the basis of problem-oriented policing. Policy recommendations for both practitioners and researchers engaged in problem-solving initiatives are offered