Cancers are composed of populations of cells with distinct molecular and phenotypic features, a phenomenon termed intra-tumor heterogeneity (ITH). ITH in lung cancers has not been well studied. We ...applied multi-region whole exome sequencing (WES) on 11 localized lung adenocarcinomas. All tumors showed clear evidence of ITH. On average, 76% of all mutations and 20/21 known cancer gene mutations were identified in all regions of individual tumors suggesting single-region sequencing may be adequate to identify the majority of known cancer gene mutations in localized lung adenocarcinomas. With a median follow-up of 21 months post-surgery, 3 patients have relapsed and all 3 patients had significantly larger fractions of subclonal mutations in their primary tumors than patients without relapse. These data indicate larger subclonal mutation fraction may be associated with increased likelihood of postsurgical relapse in patients with localized lung adenocarcinomas.
This paper analyzes the black hole and gray hole attack which are the possible packet dropping attacks in wireless mesh networks. In a black hole attack, a malicious node makes all the traffic travel ...through it, claiming to have the shortest route to all other nodes in the network and instead of forwarding the packets, a malicious node simply drops it. In a gray hole attack (selective forwarding attack) where a misbehaving mesh router just forwards a subset of the packets it receives but drops the others. In this paper we have shown that there is 100% packet loss and there is rigorous decrease in throughput and network performance as compared to gray hole attack. Simulations are done using Qualnet 5.0.
To become independent of backbone networks leading to cheap deployments, the traditional single-hop approach needs to be replaced by Wireless Mesh Networks (WMNs). Wireless Mesh Networks is ...cost-effective alternative to wireless local area networks. Due to multi hop networking, WMN requires multi hop routing protocol. Mostly the nature of data is from client to gateway and vice versa. So, according to IEEE 802.11s Draft 3.0, HWMP routing protocol is adopted. In this paper, we analyzed the throughput of HWMP protocol with increase in number of nodes and increase in size of packets using simulation model.
Using wireless mesh networks to offer Internet connectivity is becoming a popular choice for wireless Internet service providers as it allows fast, easy, and inexpensive network deployment. However, ...security in WMNs is still in its infancy as very little attention has been devoted thus so far to this topic by the research community and so it has become more vulnerable to various types of attacks. In this paper we described various DoS attacks and their detection methods in wireless mesh networks. DoS attacks can compromise the availability of wireless mesh networks as such attacks would essentially prevent one or more nodes from accessing or providing specific services.
Wireless mesh networks (WMNs) have emerged as a key technology for next-generation wireless networking, due to independency of backbone networks. However, to make a WMN be all it can be, considerable ...research efforts are still needed. As the available MAC and routing protocols applied to WMNs do not have enough scalability as throughput drops significantly as the number of nodes or hops increases. Existing security schemes may be effective for certain types of attacks, but they lack a comprehensive mechanism to prevent attacks from different protocol layers. Similar problems exist in other networking protocols. Thus, existing communication protocols, ranging from routing, MAC, and physical layers, need to be revisited and enhanced. In some circumstances, new protocols need to be invented. Researchers have started to revisit the protocol design of existing wireless networks. This paper presents a detailed investigation of current research issues and challenges in wireless mesh networks.
Due to Wi-Fi Alliance (WFA)'s marketing, 802.11 became a universal solution for wireless connectivity. However, still a WLAN depends on wired infrastructure that interconnects the central Access ...Points (APs). To become independent of backbone networks leading to cheap deployments, the traditional single-hop approach needs to be replaced by Wireless Mesh Networks (WMNs). With 802.11s an integrated WMN approach is under development that adds the necessary functionality for interworking, security and routing. 802.11s is an extension to 802.11 to provide multi-hop networking. In this paper, we compare the 802.11 and 802.11s standard in terms of objectives, applications, architecture, physical layer (multiple radios), MAC layer protocols, Routing algorithms, different security requirements in Wireless mesh networks than 802.11 WLAN and at the last the need of cross layer design in WMN is explained.
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