The environmental friendliness and excellent thermal stability proves Cesium Tin Iodide (CsSnI3) as one of the promising materials for the commercialization of the perovskite solar cells. However, CsSnI3solar cells suffer from poor efficiency due to having low open-circuit voltage, VOCattributed to poor absorber film quality as well as energy level mismatch at the interfaces between different layers like transparent front contact (typically used Indium Tin Oxide, ITO) - carrier transport layer interface. In order to improve the energy matching between ITO - hole transport layer (HTL) interface, a typical inverted planar perovskite solar cell (IT O/HT L/CsSnI3/ET L) is numerically simulated (Finite difference time domain, FDTD analysis followed by electrical simulation) here, with various types of doped ITO layers having higher work functions (≥ 5eV), replacing the typical undoped ITO material having lower work function (≤ 4.7eV). The simulation results illustrate that, utilizing the higher work function and optical transparency of available doped ITO materials the VOCof a typical CsSnI3cell can be increased from 0.5V up to 1.1V which will make it possible to achieve power conversion efficiency as high as 11% (which is 3.3% with undoped ITO), without adopting complex modification of the absorber layer.

Improving quality of service (QoS) of low power and lossy networks (LLNs) in Internet of things (IoT) is a major challenge. Cluster-based routing technique is an effective approach to achieve this goal. This paper proposes a QoS-aware clustering-based routing (QACR) mechanism for LLNs in Fog-enabled IoT which provides a clustering, a cluster head (CH) election, and a routing path selection technique. The clustering adopts the community detection algorithm that partitions the network into clusters with available nodes' connectivity. The CH election and relay node selection both are weighted by the rank of the nodes which take node's energy, received signal strength, link quality, and number of cluster members into consideration as the ranking metrics. The number of CHs in a cluster is adaptive and varied according to a cluster state to balance the energy consumption of nodes. Besides, the protocol uses the CH role handover technique during CH election that decreases the control messages for the periodic election and cluster formation in detail. An evaluation of the QACR has performed through simulations for various scenarios. The obtained results show that the QACR improves the QoS in terms of packet delivery ratio, latency, and network lifetime compared to the existing protocols.

Ascribed to better immunity to drain induced barrier lowering (DIBL) and enhanced analog/RF performance, tri-material double gate (TMDG) MOSFET proves to be superior over conventional DG MOSFET configurations. On the other hand, further improvement in various short channel effects (SCE) as well as high tolerance in gate misalignment can be achieved by using gate underlap design in typical DG structures. Merging these two features in this work, a TMDG MOSFET design with 20 nm physical gate length is studied for various symmetrical underlap lengths using 2D device simulation. Extensive analysis are performed to investigate notable analog/RF parameters like transconductance (gm), output conductance (gd), intrinsic gain (Av), intrinsic capacitance and cut-off frequency (fT) along with some SCEs like DIBL and subthreshold swing (SS) for various gate underlap designs. Additionally, some of the performance parameters are compared with single material (SM) and double material (DM) DG architectures. Thus this work provides a thorough investigation of the influence of gate material and gate underlap designs for DG MOSFET compatible for analog/RF application.

With 20 million installs a day , third-party apps are a major reason for the popularity and addictiveness of Facebook. Unfortunately, hackers have realized the potential of using apps for spreading malware and spam. The problem is already significant, as we find that at least 13% of apps in our dataset are malicious. So far, the research community has focused on detecting malicious posts and campaigns. In this paper, we ask the question: Given a Facebook application, can we determine if it is malicious? Our key contribution is in developing FRAppE-Facebook's Rigorous Application Evaluator-arguably the first tool focused on detecting malicious apps on Facebook. To develop FRAppE, we use information gathered by observing the posting behavior of 111K Facebook apps seen across 2.2 million users on Facebook. First, we identify a set of features that help us distinguish malicious apps from benign ones. For example, we find that malicious apps often share names with other apps, and they typically request fewer permissions than benign apps. Second, leveraging these distinguishing features, we show that FRAppE can detect malicious apps with 99.5% accuracy, with no false positives and a high true positive rate (95.9%). Finally, we explore the ecosystem of malicious Facebook apps and identify mechanisms that these apps use to propagate. Interestingly, we find that many apps collude and support each other; in our dataset, we find 1584 apps enabling the viral propagation of 3723 other apps through their posts. Long term, we see FRAppE as a step toward creating an independent watchdog for app assessment and ranking, so as to warn Facebook users before installing apps.

Online social networks (OSNs) have become a popular new vector for distributing malware and spam, which we refer to as socware. Unlike email spam, which is sent by spammers directly to intended victims, socware cascades through OSNs as compromised users spread it to their friends. In this paper, we analyze data from the walls of roughly 3 million Facebook users over five months, with the goal of developing a better understanding of socware cascades.

With 20 million installs a day, third-party apps are a major reason for the popularity and addictiveness of Facebook. Unfortunately, hackers have realized the potential of using apps for spreading malware and spam. The problem is already significant, as we find that at least 13% of apps in our dataset are malicious. So far, the research community has focused on detecting malicious posts and campaigns.

Internet mobility protocols are designed to support handover between different wireless networks. Many of them, such as Mobile IPv6, suffer problems such as high handover latency, high packet overhead, high packet loss during handoff, requirement for infrastructure change, etc. To solve these problems, SEamless MObility using SHIM6 (SEMO6), a multihoming based mobility protocol framework for host mobility, has been proposed. The goal of this paper is to experimentally validate that SEMO6 can perform better than MIPv6. We show that SEMO6 can improve the performance of applications in IP-based mobile networks.

In network layer based mobility protocols, such as mobile IP, the correspondent node is not aware of handovers and therefore continues to send data at the same rate as before the handover which may exhibit network unfriendliness, especially when the capacities of the two subnets differ significantly. On the contrary, transport layer based mobility protocols, such as SIGMA, do not show such phenomena. The objective of this paper is to evaluate and compare the network friendliness of network and transport layer based mobility protocols. Experimental results obtained from laboratory prototypes show that network unfriendliness is inevitable in the network layer based mobility protocols during handover when there is a large difference in capacities between the two networks. Transport layer based mobility protocols are, however, more network friendly than network layer based protocols.

IETF has proposed mobile IPv6-based network mobility (NEMO) basic support protocol (BSP) to support network mobility. NEMO BSP inherits all the drawbacks of mobile IPv6, such as inefficient routing path, single point of failure, high handover latency and high packet overhead. To address these drawbacks, a new network mobility scheme, called seamless IP-diversity based network mobility (SINEMO), has been proposed. The goal of this paper is to validate with experimental data that SINEMO performs better than NEMO BSP. We show that SINEMO can improve the performance of IP based mobile networks.