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Distributed network emulators allow users to perform network evaluation by running large-scale virtual networks over a cluster of fewer machines. While they offer accessible testing environments for researchers to evaluate their contributions and for the community to reproduce its results, their use of limited physical network and compute resources can silently and negatively impact the emulation results. In this paper, we present a methodology that uses linear optimization to extract information about the physical infrastructure from emulation-level packet delay measurements, in order to pinpoint the root causes of emulation inaccuracy with minimal hypotheses. We evaluate the precision of our methodology using numerical simulations and then show how its implementation performs in a real network scenario. [ABSTRACT FROM AUTHOR]

Terrestrial infrastructure-based wireless networks do not always guarantee their resources will be shared uniformly by nodes in vehicular networks. This is due mainly to the uneven and dynamic geographical distribution of vehicles and path loss effects. In this paper, we leverage multiple fifth-generation (5G) unmanned aerial vehicles (UAVs) to enhance fairness in network resource allocation among vehicles by positioning UAVs on-demand as “flying communication infrastructure”. We propose a deep reinforcement learning (DRL) approach to determine UAVs’ position to improve network resource allocation fairness and efficiency while considering the UAVs’ flying range, communication range, and energy constraints. We use a parametric fairness function to attain a number of resource allocation objectives ranging from maximizing the total throughput of vehicles, maximizing minimum throughput, and achieving proportional bandwidth allocation. Simulation results show that the proposed DRL approach to UAV positioning can improve network resource allocation according to the targeted fairness objective. [ABSTRACT FROM AUTHOR]

In this article, we introduce a novel dynamic controller assignment algorithm targeting connected vehicle services and applications, also known as Internet of Vehicles (IoV). The proposed approach considers a hierarchically distributed control plane, decoupled from the data plane, and uses vehicle location and control traffic load to perform controller assignment dynamically. We model the dynamic controller assignment problem as a multi-agent Markov game and solve it with cooperative multi-agent deep reinforcement learning. Simulation results using real-world vehicle mobility traces show that the proposed approach outperforms existing ones by reducing control delay as well as packet loss. [ABSTRACT FROM AUTHOR]

Dose‐dense adjuvant chemotherapy is standard of care in high‐risk early breast cancer patients. However, its role in HER2‐positive patients is still uncertain. In this exploratory analysis of the GIM2 trial, we investigated the efficacy of dose‐dense chemotherapy in HER2‐positive breast cancer patients with or without exposure to trastuzumab. In the GIM2 trial, node‐positive early breast cancer patients were randomized to receive four cycles of (fluorouracil)epirubicin/cyclophosphamide followed by four cycles of paclitaxel administered every 2 (dose‐dense) or 3 (standard‐interval) weeks. After approval of adjuvant trastuzumab, protocol was amended in April 2006 to allow use of trastuzumab for 1 year after chemotherapy completion in HER2‐positive patients. The efficacy of dose‐dense chemotherapy in terms of disease‐free survival (DFS) and overall survival (OS) was assessed according to HER2 status and trastuzumab use. Out of 2,003 breast cancer patients, HER2 status was negative/unknown in 1,551 patients; among the 452 patients with HER2‐positive breast cancer, chemotherapy alone or followed by trastuzumab was given to 320 and 132 patients, respectively. Median follow‐up was 8.1 years. No significant interaction between HER2 status, trastuzumab use and chemotherapy treatment was observed for both DFS (p = 0.698) and OS (p = 0.708). Nevertheless, there was no apparent benefit in the HER2‐positive group treated with trastuzumab (DFS: HR, 0.99; 95% CI 0.52–1.89; OS: HR, 0.95; 95% CI 0.37–2.41). Although dose‐dense chemotherapy was associated with a significant survival improvement in high‐risk breast cancer patients, its benefit appeared to be smaller (if any) in patients with HER2‐positive disease who received adjuvant trastuzumab. What's new? Dose‐dense chemotherapy is standard of care in high‐risk early breast cancer; however, its role in HER2‐positive patients is still uncertain. In this exploratory analysis of the GIM2 trial, we showed that the benefit of dose‐dense chemotherapy appeared to be small (if any) in HER2‐positive patients who received trastuzumab raising concerns on the need of chemotherapy escalation approaches in this setting. These findings may guide the choice of adjuvant chemotherapy in HER2‐positive early breast cancer patients. [ABSTRACT FROM AUTHOR]

Ultra-dense networks (UDNs) are a natural deployment evolution for handling the tremendous traffic increase related to the emerging 5G services, especially in urban environments. However, the associated infrastructure cost may become prohibitive. The evolving paradigm of network slicing can tackle such a challenge while optimizing the network resource usage, enabling multi-tenancy and facilitating resource sharing and efficient service-oriented communications. Indeed, network slicing in UDN deployments can offer the desired degree of customization in not only vanilla radio access network (RAN) designs, but also in the case of disaggregated multi-service RANs. In this article, we devise a novel multi-service RAN environment, RAN runtime, capable of supporting slice orchestration procedures and enabling flexible customization of slices as per tenant needs. Each network slice can exploit a number of services, which can be either dedicated or shared between multiple slices over a common RAN. The novel architecture we present concentrates on the orchestration and management systems. It interacts with the RAN modules, through the RAN runtime, via a number of new interfaces enabling a customized dedicated orchestration logic for each slice. We present results for a disaggregated UDN deployment where the RAN runtime is used to support slice-based multi-service chain creation and chain placement, with an auto-scaling mechanism to increase the performance. [ABSTRACT FROM AUTHOR]

Liver metastases are very common in metastatic breast cancer (MBC); current treatments for these lesions are based on systemic chemotherapy, endocrine- or human epidermal growth factor receptor 2 (HER2)-targeted therapy, and palliative therapy. However, no standard approach has been clearly identified for second and further chemotherapy lines in MBC patients. In the phase III clinical trial EMBRACE, eribulin was particularly effective in reducing liver lesions and improving both overall survival and progression-free survival in liver MBC patients. In this series, we collected 8 case reports of Italian clinical practice in which eribulin has shown significant efficacy in reducing liver metastases in MBC patients: complete response was reported in 2 patients, and 4 patients achieved partial response. The treatment was well tolerated, thus confirming that eribulin is a suitable therapeutic option for elderly patients and for those who have metastatic HER2-negative disease. In the setting of MBC, the sequencing of therapeutic agents should consider expected response, side effects, tumor characteristics, and patient’s preferences, in order to successfully tailor the most appropriate therapy beyond earlier lines. [ABSTRACT FROM AUTHOR]

New applications where anyone can broadcast high quality video are becoming very popular. Internet services providers (ISPs) may take the opportunity to propose new high quality multicast services to their clients. Because of its centralized control plane, software defined networking (SDN) enables the deployment of such a service in a flexible and bandwidth-efficient way. But deploying large-scale multicast services on SDN requires smart group membership management and a bandwidth reservation mechanism with QoS guarantees that should neither waste bandwidth nor impact too severely best effort traffic. In this paper, we propose: 1) a scalable multicast group management mechanism based on a network function virtualization approach for software defined ISP networks to implement and deploy multicast services on the network edge and 2) the lazy load balancing multicast (L2BM) routing algorithm for sharing the core network capacity in a friendly way between guaranteed-bandwidth multicast traffic and best-effort traffic and that does not require costly real-time monitoring of link utilization. We have implemented the mechanism and algorithm, and evaluated them both in a simulator and a testbed. In the testbed, we experimented the group management at the edge and L2BM in the core with an open vSwitch-based QoS framework and evaluated the performance of L2BM with an exhaustive set of experiments on various realistic scenarios. The results show that L2BM outperforms other state-of-the art algorithms by being less aggressive with best-effort traffic and accepting about 5%–15% more guaranteed-bandwidth multicast join requests. [ABSTRACT FROM PUBLISHER]

Software-Defined Wireless Networking (SDWN) is an emerging approach based on decoupling radio control functions from the radio data plane through programmatic interfaces. Despite diverse ongoing efforts to realize the vision of SDWN, many questions remain open from multiple perspectives such as means to rapid prototype and experiment candidate software solutions applicable to real-world deployments. To this end, emulation of SDWN has the potential to boost research and development efforts by re-using existing protocol and application stacks while mimicking the behavior of real wireless networks. In this article, we provide an in-depth discussion on that matter focusing on the Mininet-WiFi emulator design to fill a gap in the experimental platform space. We showcase the applicability of our emulator in an SDN wireless context by illustrating the support of a number of use cases aiming to address the question on how far we can go in realistic SDWN experiments, including comparisons with the results obtained in a wireless testbed. Finally, we discuss the ability to replay packet-level and radio signal traces captured in the real testbed toward a virtual yet realistic emulation environment in support of SDWN research. [ABSTRACT FROM AUTHOR]

Content-Centric Networks (CCNs) are fundamental evolutionary technologies that promise to form the cornerstone of the future Internet. The information flow in these networks is based on named data requesting, in-network caching, and forwarding, which are unique and can be independent of IP routing. As a result, common IPbased network tools such as ping and traceroute can neither trace a forwarding path in CCNs nor feasibly evaluate CCN performance. We propose ?contrace,? a network tool for CCNs (particularly, CCNx implementation running on top of IP) that can be used to investigate the round-trip time (RTT) between content forwarder and consumer, the states of in-network cache per name prefix, and the forwarding path information per name prefix. We report a series of experiments conducted using contrace on a CCN topology created on a local testbed and the GEANT network topology emulated by the Mini-CCNx emulator. The results confirm that contrace is not only a useful tool for monitoring and operating a network, but also a helpful analysis tool for enhancing the design of CCNs. Further, contrace can report the number of received interests per cache or per chunk on the forwarding routers. This enables us to estimate the content popularity and design more effective cache control mechanisms in experimental networks. [ABSTRACT FROM PUBLISHER]

In this article, we discuss user-centric networks as a way of, if not completely solving, considerably mitigating the problem of sharing limited network capacity and resources efficiently and fairly. UCNs are self-organizing networks where the end user plays an active role in delivering networking functions such as providing Internet access to other users. We propose to leverage the recently proposed SDN paradigm to enable cooperation between wireless nodes and provide capacity sharing services in UCNs. Our SDNbased approach allows coverage of existing network infrastructure (e.g., WiFi or 3GPP) to be extended to other end users or ad hoc networks that would otherwise not be able to have access to network connectivity and services. Moreover, the proposed SDN-based architecture also takes into account current network load and conditions, and QoS requirements. Another important feature of our framework is that security is an integral part of the architecture and protocols. We discuss the requirements for enabling capacity sharing services in the context of UCNs (e.g., resource discovery, node admission control, cooperation incentives, QoS, security) and how SDN can aid in enabling such services. The article also describes the proposed SDN-enabled capacity sharing framework for UCNs. [ABSTRACT FROM PUBLISHER]

We present the Direct Code Execution (DCE) environment for ns-3, notable for being the first free open source framework for integrating Linux kernel and application code within a leading discrete-event network simulator. This new approach has many potential advantages over virtual-machine-based frameworks in terms of realism, reproducibility, avoidance of realtime execution constraints, configuration management, and the ability to debug a network-wide experiment from a single address space using common debugging tools. We provide an overview of DCE and illustrate some key features of this framework with two use cases, one involving thttpd, an HTTP server implementation, and another one involving the udp-perf traffic generator. [ABSTRACT FROM PUBLISHER]

We present an efficient message delivery framework, called MeDeHa, which enables communication in an internet connecting heterogeneous networks that is prone to disruptions in connectivity. MeDeHa is complementary to the IRTF's Bundle Architecture: besides its ability to store messages for unavailable destinations, MeDeHa can bridge the connectivity gap between infrastructure-based and multi-hop infrastructure-less networks. It benefits from network heterogeneity (e.g., nodes supporting more than one network and nodes having diverse resources) to improve message delivery. For example, in IEEE 802.11 networks, participating nodes may use both infrastructure- and ad-hoc modes to deliver data to otherwise unavailable destinations. It also employs opportunistic routing to support nodes with episodic connectivity. One of MeDeHa's key features is that any MeDeHa node can relay data to any destination and can act as a gateway to make two networks inter-operate or to connect to the backbone network. The network is able to store data destined to temporarily unavailable nodes till the time of their expiry. This time period depends upon current storage availability as well as quality-of-service needs (e.g., delivery delay bounds) imposed by the application. We showcase MeDeHa's ability to operate in environments consisting of a diverse set of interconnected networks and evaluate its performance through extensive simulations using a variety of scenarios with realistic synthetic and real mobility traces. Our results show significant improvement in average delivery ratio and a significant decrease in average delivery delay in the face of episodic connectivity. We also demonstrate that MeDeHa supports different levels of quality-of-service through traffic differentiation and message prioritization. [ABSTRACT FROM AUTHOR]