TWO-HOP RELAY PROTOCOL

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Antimalarial activity of primaquine operates via a two-step biochemical relay

Antimalarial activity of primaquine operates via a two-step biochemical relay

1.7 Hz, 1 H), 8.40 (dd, J = 7.9, 1.7 Hz, 1 H), 7.75 (dd, J = 7.9, 4.9 Hz, 1 H), 6.12 (s, 1 H), 4.11 (dd, J = 13.1, 6.7 Hz, 1 H), 3.05 (t, J = 7.4 Hz, 2 H), 1.92–1.74 (m, 4 H) and 1.42 (d, J = 6.5 Hz, 3 H); MS for C 14 H 17 N 3 O 2 [M + H] + found 260.35. In vitro metabolism and redox cycling reactions. Human liver microsomes (HLM, BD Biosciences) and CYP2D6-expressing baculosomes from the Vivid CYP450 kit (Life Technologies) were used for compound metabolic conversions as per manufacturer’s instructions with minor modifications. For HLM, compounds (30 μM final concentration) were incubated in the presence of NAPDH Regen- eration System Solution A and B (BD Biosciences) at 37 °C for 2 h in a total volume of 100 μl of phosphate reaction buffer. For CYP2D6 baculosomes reaction, a 2× master mix (50 μl) was prepared containing reaction buffer, baculosomes, regen- eration system and NADP + (all from Life technologies). Compounds (30 μM final concentration) were prepared in 40 μl reaction buffer containing NADP + as per kit protocol. The total volume was brought to 100 μl with reaction buffer and reactions incubated at 37 °C for 2 h. For CYP2D6 inhibition, we first determined paroxetine inhibitory pro file using Vivid CYP2D6 Blue kit (Life Technologies) according to manufacturer’s instructions. For gametocytocidal assays, master mixes without
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Tensor coding for three-hop MIMO relay systems

Tensor coding for three-hop MIMO relay systems

In the context of cooperative networks [5]-[6],[9]-[10], the use of tensor coding at the transmitting nodes and an amplify- and-forward (AF) relaying protocol (where the relay retransmits data without decoding) leads to received signals that form high- order tensors. A tensor space-time coding (TSTC) was introduced in [3] and applied to a non-cooperative MIMO system, allowing spreading and multiplexing the transmitted symbols, in both space and time domains. In [5], TSTC at the source and the relay was applied to a two-hop MIMO relay system whose signals received at destination satisfy a fourth- order tensor model based on a nested Tucker decomposition (NTD). In [6]-[9], three-hop MIMO systems were addressed exploiting the structure of a Khatri-Rao space-time (KRST) coding to derive semi-blind receivers based on parallel factor (PARAFAC) models. However, there are still few results on tensor approaches for multi-hop scenarios.
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R-SWAP: Relay based atomic cross-chain swap protocol

R-SWAP: Relay based atomic cross-chain swap protocol

Abstract—In this paper, we consider the problem of cross-chain transactions where parties that do not trust each other safely exchange digital assets across blockchains. Open blockchains models are decentralized ledgers that keep records of transac- tions. They are comparable with distributed account books. While they have proven their potential as a store of value, exchanging assets across several blockchains remains a challenge. Our paper proposes a new protocol, R-SWAP, for cross-chain swaps that outperforms existing solutions. Our protocol is built on top of two abstractions: relays and adapters that we formalize for the first time in this paper. Furthermore, we prove the correctness of R-SWAP and analytically evaluate its performances, in terms of cost and latency. Moreover, we evaluate the performances of R-SWAP in two case studies showing the generality of our approach: atomic swaps between Ethereum and Bitcoin (two popular permissionless blockchains) and atomic swaps between Ethereum and Tendermint (one permissionless and one permis- sioned blockchain).
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Performance Analysis of OLSR Multipoint Relay Flooding in Two Ad Hoc Wireless Network Models

Performance Analysis of OLSR Multipoint Relay Flooding in Two Ad Hoc Wireless Network Models

Rapport de recherche n ° 4260  Septembre 2001  26 pages Abstract: We analyze the performance of ad hoc pro-active routing proto- col OLSR. In particular we focuse on the multipoint relay concept which is the most salient feature of this protocol and which brings the most signicant breakthrough in performance. We will anlyse the performances in two radio network models: the random graph model and the unit graph. The random graph is more suitable for indoor networks, and the unit graph is more suit- able for outdoor networks. We compare the performance of OLSR with the performance of link state protocols using full ooding, such as OSPF.
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Maximizing the Probability of Delivery of Multipoint Relay Broadcast Protocol in Wireless Ad Hoc Networks with a Realistic Physical Layer

Maximizing the Probability of Delivery of Multipoint Relay Broadcast Protocol in Wireless Ad Hoc Networks with a Realistic Physical Layer

depends on a unique threshold. In the LNS model, we have assumed that the communication radius R is equal to the distance such that p (R) = 0.5, which is 100 in this example. Throughout this paper, we use the simplified notation p(u, v) instead of p (d(u, v)). In this paper, we assume that each node is aware of its 2-hop neighbors, which can be achieved, for example, by at least two rounds of beacon (HELLO) messages: nodes can indeed insert the identifiers of their neighbors in their own beacon messages. The question of correctly gathering neighborhood information considering the LNS model is a whole problem, because HELLO messages are themselves subject to the probability of correct reception. This problem is not in the scope of this paper, but we nevertheless give in Sec. 4 indications of how it can be considered when generating graphs for simulations, and what decisions we took in the implementation of our simulator.
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COLiDeR: A cross-layer protocol for two-path relaying

COLiDeR: A cross-layer protocol for two-path relaying

SN R R 2 ,R 1 43 dB SN R R 1 ,D SN R R 2 ,D > 40 dB 3.4.2. β parameter selection As mentioned at the beginning of this section, when a relay crosses from area B to C, it estimates that it cannot handle two signals anymore and changes T wo Signals from 1 to 0. It leads the source station to transition to a lower state (Cf. § 3.2) and the relay itself to switch to IF decoding. As a result, a low β value will cause the system to be in the low two-path relaying states, reducing the maximum throughput, while a large β value will lead to an aggressive pursuit of the higher states, with the higher maximum throughput, but at the cost of higher packet losses. With the β parameter impacting the throughput and packet delivery rate, in the following we evaluate its impact on both these metrics. We place the 4 USRPs of our testbed so as to obtain the SNRs values indicated in Table 1. For three different values of β we carry a series of experiments in which we change the source transmission gain G, which directly affects SN R S,R 1 and SN R S,R 2 .
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Optimal Cooperative MAC Protocol with Efficient Selection of Relay Terminals

Optimal Cooperative MAC Protocol with Efficient Selection of Relay Terminals

I. I NTRODUCTION One of the major properties of Wireless Mesh Networks (WMNs) consists in the possibility of breaking long distances into a series of shorter hops. Apart from increasing the signal quality of the links, the mesh architecture allows the coopera- tive forwarding of data packet through intermediate terminals in the network. The forwarding scheme can be envisioned at several network layers. However, implementing the forwarding scheme at the lowest layers renders the protocol more reactive to network conditions and minimizes the transmission delay since each layer adds its own processing time and hence includes its own latency. Cooperative protocols implement two main functions: cooperative transmissions are managed at the physical (PHY) layer whereas the set up of the cooperation is done at the medium access control (MAC) layer. At the PHY layer, cooperative communications increase the wireless link reliability. In a cooperative scenario, a source terminal S sends data to a destination terminal D through a direct path. One or several relay terminals help the transmission by receiving the source message and forwarding it to D through a relaying path (see Figure 1). Hence the direct path is rendered more robust [1]–[4]. However, this comes at the price of bandwidth consumption so that the system operates at diminished capacity 1 . Hence, further optimization
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Throughput-efficient Relay assisted Hybrid ARQ

Throughput-efficient Relay assisted Hybrid ARQ

chunks related to this message ` to the destination, the source trusts the relay in managing this message `, and the source decides to send a new message ` 0 in parallel. This protocol is expected to provide a higher throughput since two messages are sent simultaneously. However, the message error rate (MER) is also likely to be higher since at the destination, interference (one message is coming from the relay and another one from the source) occurs and degrades the detection. As a result, more transmissions are likely to occur, and one can hope that MER increase is small enough. More precisely, assuming we are starting a protocol session, the source transmits sequence x (c) 1 , (c = 1, . . . , r), to the destination while the relay overhears the source transmission where r is the HARQ round from which the relay successfully decodes the message 1. At round r + 1, the relay transmits the sequence x (r+1) 1 , to the destination while the source transmits
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TDMA-aware Routing Protocol for Multi-hop Communications in Vehicular Ad Hoc Networks

TDMA-aware Routing Protocol for Multi-hop Communications in Vehicular Ad Hoc Networks

II. R ELATED WORK The simultaneous transmissions in VANETs due to mul- tiple concurrent vehicles, lead to an increase in the col- lisions rate which can degrade the network performance in terms of packet delivery ratio and delay. The relevance of this issue has been confirmed by the development of a specific IEEE standard to support VANETs. The IEEE 802.11p [5] which is the emerging standard deployed to enable vehicular communication, is a contention-based MAC protocol, using a priority based access scheme that employs both Enhanced Distributed Channel Access (EDCA) and Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) mechanisms [6]. This standard is a contention- based MAC method that cannot ensure a reliable broadcast mechanism with bounded access delays. This disadvantage is particularly detrimental in VANETs which are specially designed to improve road safety. Despite that, several multi- hop routing protocols use this approach to transmit data. For instance, in [7] the authors have proposed an opportunistic broadcast protocol named OB-VAN to overcome the problem of packet delivery in VANETs. OB-VAN uses a modified 802.11 MAC layer using an active signaling mechanism to select a suitable next-hop relay from all the candidate vehicles that have correctly received the packet. Since OB- VAN uses a contention- free MAC schemes, it is possible that it cannot operate well in sparse or dense mobility scenarios. Many alternatives exist to mitigate collision between vehicle transmissions by using a contention-free protocols at the medium access layer. For instance, the authors in [8] have proposed a cross-layer MAC and routing scheme based on contention-free MAC protocol called VeMAC [9] for multi- hop in-vehicle Internet access. The goal of this work is to propose a routing protocol which allows a vehicle to discover the existence of a gateway connected to the Internet and exchange packets with it through multi-hop communications. The proposed routing protocol consists of two main phases: gateway discovery and packet forwarding. The first phase defines how a vehicle can discover the existence of a gateway installed along the highway, while the second one defines how a packet is transmitted via multi-hop communications from a vehicle to a gateway and vice versa. However, this multi-hop communication scheme is limited only to infotain- ment applications (i.e. Internet access) and does not support safety applications, which makes it unsuitable for VANETs which are specially designed to improve road safety. In this paper, we focus on this category of approach and we propose a new TDMA-aware Routing protocol for Multi- hop Communications in VANETs, in which the next hop
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Improvement of range-free localization technology by a novel DV-hop protocol in wireless sensor networks

Improvement of range-free localization technology by a novel DV-hop protocol in wireless sensor networks

Strength Indicator (RSSI) [11] , Time of Arrival (TOA) [12] , Time Difference of Arrival (TDOA) [13] , and Angle of Arrival (AOA) [14] . GPS (Global Positioning System) [10] is the most well-known range-based technique using TOA or TDOA. However, the GPS devices not only consume lots of energy, but also fail to work indoors. An alternative tech- nique is GSM (Global System for Mobile communications), using RSSI and AOA methods. Note that GPS and GSM sup- port localization by using complex and expensive systems. Another technology is UWB (Ultra Wide Band) which can be used to measure time of flight with high precision [15] . The range-based techniques have two major draw- backs. First, the range information is very easily affected by multipath fading, noise and environment variations. Second, usually, additional ranging devices are needed, which consume more energy and increase the overall cost. While the range-based scheme uses the distance or angle between nodes, the range-free scheme uses connec- tivity information between nodes. In this scheme, the nodes that are aware of their positions are called anchors, while others are called normal nodes. Anchors are fixed, while normal nodes are usually mobile. Normal nodes first gather the connectivity information as well as the posi- tions of anchors, and then calculate their own positions. Since no ranging information is needed, the range-free scheme can be implemented on low-cost wireless sensor networks. Another advantage of range-free scheme is its robustness; the connectivity information between nodes is not easily affected by the environment. As a result, we focus our research on the range-free scheme.
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Performance of a fixed reward incentive scheme for two-hop DTNs with competing relays

Performance of a fixed reward incentive scheme for two-hop DTNs with competing relays

In [SBEP17], the source oers rewards that depend upon the meeting time with the condition that only the rst one to deliver the message receives its reward. Since the mobility model is random, a relay that meets the source later has lower probability of being the rst to deliver the message and hence receiving the reward. The reward proposed to a relay is inversely proportional to its success probability, and is such that a relay always accepts the message. The analysis relies heavily on the assumption that the relays do not discard a message once they accept it from the source. This assumption may be realistic in participative networks in which nodes are altruistic. On the other hand, when nodes are selsh, as is the case in the present paper, they could decide to throw away a message once it is not longer protable to keep it (because the probability of success is too small) and reduce their costs. This possibility to reject or drop the messages is the main dierence of our work with [SBEP17], in which no strategic interaction between relays was considered.
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Estimating File-Spread in Delay Tolerant Networks under Two-Hop Routing

Estimating File-Spread in Delay Tolerant Networks under Two-Hop Routing

5 Conclusion In this paper, we tackled the problem of estimating file-spread in DTNs with two-hop routing. Apart from providing solid analytical basis to our estimation framework, we also provided insightful conclusions validated with simulations. Some of the important insights are: (i) the deterministic fluid model can indeed be a good predictor with a large number of nodes, (ii) the Kalman filter can track the spreading process quite accurately provided that measurements as well as updates are taken sufficiently fast, (iii) during the initial phase of spreading when the amount of sample measures is still low, the MMSE estimator can be used for estimating the level-crossing times of sufficiently low threshold levels, and (iv) as time progresses, the MMSE estimator becomes less useful, but the Kalman filter would be available at later phases to provide accurate estimates. Applying the real-time estimations for on-line adaptive control of the spreading process is a topic of our ongoing research.
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End-To-End Performance Analysis of Two-Hop Asynchronous Cooperative Diversity

End-To-End Performance Analysis of Two-Hop Asynchronous Cooperative Diversity

System 3 : R1 and R2 receive the data, estimate the channel parameters as shown in section III but no separately decoding is performed in r-VAA, then an unprocessed version of the receiv[r]

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Robust Relay Beamforming for MIMO Multi-Relay Networks with Imperfect Channel Estimation

Robust Relay Beamforming for MIMO Multi-Relay Networks with Imperfect Channel Estimation

Abstract—In this paper, we consider a dual-hop Multiple Input Multiple Output (MIMO) wireless multi-relay network, in which a source-destination pair both equipped with multiple antennas communicates through multiple half-duplex amplify-and-forward (AF) relay terminals which are also with multiple antennas. Imperfect channel estimations for all nodes are considered. We propose a novel robust linear beamforming at the relays, based on the QR decomposition filter at the destination node which performs successive interference cancellation (SIC). Using Law of Large Number, we obtain the asymptotic rate, upon which the proposed relay beamforming is optimized. Simulation results show that the asymptotic rate matches with the ergodic rate well. Analysis and simulation results demonstrate that the pro- posed beamforming outperforms the conventional beamforming schemes.
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Medium access protocol (MAC) design for wireless multi-hop ad hoc and sensor networks

Medium access protocol (MAC) design for wireless multi-hop ad hoc and sensor networks

Spatial reuse flip side in sensor networks: Our work is based on the two-hop interference model; one of the most important assumptions in wireless ad hoc and sensor networks. Recall that the two-hop interference model is that the transmission power of node n decays with the distance, and it is assumed to not interfere with the transmission of a node that is located three-hops away. Based on this assumption, a time slot is reused three hops away. However, real implementations have called into question the reliability of this model [86]. The spatial reuse is shown to cause interference; i.e. two three hops away nodes assigned the same slot suffer from mutual interference. One of the proposed solution (e.g. solution adopted by SERENA [13]) to this issue is to expand the interference model to three hops; i.e. a slot is unique for a node n, its one hop-neighbors, its two-hops neighbors and its three-hop neighbors. Another interesting solution that can be adapted to the OSTR/S-OSTR protocol is to use variable slot length. The idea behind is that we deduce the appropriate slot length based on the interference level which is proportional to the reuse of the slot. The more a slot is reused the higher the interference level is, and thus the longer should be the length of that slot. Indeed, the longer the slot size is the more a node is able to manipulate interference; i.e. varying the packet length, delaying or advancing its transmission time in the slot, etc. We think that the field of slot assignment based on the interference level has not been fully explored yet, and there is a room for future enhancements to develop more realistic slot assignment techniques.
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Improvement of range-free localization technology by a novel DV-hop protocol in wireless sensor networks

Improvement of range-free localization technology by a novel DV-hop protocol in wireless sensor networks

The following table gives a brief comparison of the three algorithms (see Table 14 ). 5. Conclusion In the context of low-cost wireless ad-hoc sensor net- works, the range-free localization scheme is not only more cost-effective than range-base scheme, but also more robust. Among typical range-free localization algorithms, DV-hop algorithm shows its particular advantage for local- izing the normal nodes that have less than three neighbour anchors. Focusing on DV-hop, we have proposed two improved algorithms, Checkout DV-hop and Selective 3-Anchor DV-hop. Checkout DV-hop has better accuracy than original DV-hop algorithm because it adjusts the estimated position of a normal node based on its distance to the nearest anchor. Generally, the nearest anchor to a normal node has the most accurate estimated distance compared with other anchors. Selective 3-Anchor DV-hop algorithm outperforms Checkout DV-hop and the original DV-hop because many more candidate positions for each normal node are created, and the best candidate is chosen based on its hop counts difference with the normal node.
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Competition and cooperation between nodes in Delay Tolerant Networks with Two Hop Routing

Competition and cooperation between nodes in Delay Tolerant Networks with Two Hop Routing

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

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An effective hop-by-hop Interest shaping mechanism for CCN communications

An effective hop-by-hop Interest shaping mechanism for CCN communications

In this paper, we propose a congestion control mechanism for CCN, based on hop-by-hop Interest shaping. It relies on the assumption that any CCN router can control the future rate of data-chunks it will receive by shaping the rate of the Interest it is currently sending towards content providers, as one Interest retrieves at most one Data packet. We monitor the level of Chunks stored in the router transmission buffer in order to dynamically adjust the associated Interests rate that have generated the Chunks in that buffer. We provide a simple analytical model to demonstrate the convergence of our algorithm, complemented by simulation results to evaluate the behaviour of our solution in more complex settings.
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An improved hop-by-hop interest shaper for congestion control in named data networking

An improved hop-by-hop interest shaper for congestion control in named data networking

5. RELATED WORK A number of hop-by-hop interest shaping algorithms have been proposed in the literature. [7] proposed the simplest algorithm where the interest rate is shaped so that the returning data rate matches the reverse link capacity multiplied by a pre-determined coefficient be- tween 0 and 1. A more sophisticated shaping algorithm was proposed in [6] where the shaping rate is dynami- cally adjusted based on the instantaneous queue length and available capacity to send data packets at time t. A window-based mechanism described in [1] controls the interest sending rate of a client in TCP-like fash- ion. This mechanism was extended in [2] by adding a hop-by-hop interest shaping scheme where each flow is allocated a fair share of the link bandwidth and shaped accordingly. [5] also presented a per-flow bandwidth fair sharing mechanism. Interests exceeding the fair share are discarded with NACKs and simple AIMD schemes are used to adjust the client’s interest rate.
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Danse des villes et dans d'école : Le hip-hop

Danse des villes et dans d'école : Le hip-hop

Extrait d’entretien Professeur d’E.P.S., collège Victor Hugo : « Alors, au début de l’année, on a eu une réunion des professeurs d’E.P.S. qui ont une association sportive danse sur le département, comme tous les ans à peu près, à la rentrée, pour faire le bilan de l’année passée, pour mettre en place les projets et donc eh une collègue, donc [le professeur-relais-danse Rhône] qui est en rapport avec la mission d’action culturelle du rectorat, nous a dit qu’il y avait un financement et que ISM recherchait des établissements, cinq établissements, cinq collèges sur Lyon, sur l’Académie, non sur le département ! pour mettre en place ces pratiques culturelles qui émergent actuellement un petit peu en milieu urbain. Donc dans les professeurs présents, il y en a cinq qui se sont portés volontaires, alors plutôt des professeurs de zones difficiles où justement les pratiques hip hop sont monnaie courante là-bas et puis moi c’est pas du tout le cas (rires) parce que j’ai quand même des élèves de milieux favorisés et c’est pas une pratique eh, la pratique danse urbaine c’est pas vraiment une pratique qui leur est familièrement alors j’avais justement envie de, de voir par rapport à un public qui n’est pas spontanément partie prenante, voir comment ça pouvait se passer. Et puis en épluchant les fiches de cette classe, j’ai constaté qu’en dehors du collège ils faisaient presque tous des arts martiaux, des sports de combat donc à ce moment-là ISM a proposé plutôt que danse urbaine de faire capoeira. Voilà c’est comme ça que nous on a un cours de capoeira et qu’ailleurs c’est plutôt danse urbaine, hip-hop, etc. […] Alors pourquoi j’ai choisi cette classe, parce que au départ c’est une classe passerelle donc des élèves de quatrième pour éviter un redoublement de cinquième, font une espèce de quatrième d’adaptation pour passer en quatrième normale l’année suivante, donc une quatrième a faible effectif et sur laquelle avec mes collègues on voulait qu’il y ait un plus, un projet interdisciplinaire. Donc on était parti au mois de juin comme je vous le disais tout à l’heure, sur un projet européen. A la rentrée ça s’est transformé en projet environnement parce qu’au niveau chant y’avait tout un dossier sur l’environnement, par le professeur d’éducation musicale et eh, en fait moi j’ai un peu laissé tombé l’environnement, ou alors on peut dire environnement urbain, pour prendre l’expérience capoeira. Je sais pas où en sont mes collègues d’ailleurs dans le projet interculturel (se reprend) interdisciplinaire plutôt ! et on a pensé quand même que ces enfants qui avaient des difficultés au niveau scolaire c’était bien qu’ils soient valorisés par un projet et y’a qu’eux dans le collège qui ont la chance d’avoir cette expérience et c’était ça la volonté quoi ».
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