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Though the classical image-segmentation techniques have demonstrated their capability in various ­applications, their performance degrades severely when they are applied to segment the still Ultrasound (US) images owing to the speckle, tissue related textures, and the artefacts resulting from the ultrasonic imaging process. Although these three types of signals make a clinical decision difficult, the deterioration of edge definition caused by them severely degrades the performance of most classical boundary - detection algorithms. This review gives a bibliographical survey of the current research efforts in the area of image segmentation of still US medical images and presents some of the challenges anticipated in the years to come. A full description of the various methods is beyond the scope of this article; instead, the focus is on providing an introduction to the methods of segmentation.

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Visible Light Communication (VLC) using LEDs is emerging as a key technology for a ubiquitous communication system, because LED has the advantages of fast switching, long life expectancy, being less expensive and being visible light that is safe for the human body. The VLC system is expected to undergo rapid progress, inspiring numerous indoor and outdoor applications; however, many technical issues need to be addressed, especially in outdoor environment. In order to provide a better understanding of the research challenges of VLC, this article presents a detailed investigation of the current state-of-art concept. Open research issues such as channel modelling and modulation techniques are also discussed, with the objective of triggering new research interest in this field. The paper also introduces our ongoing development of Wireless USB Interface and the project VIDAS.

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This article discusses the challenges for Database Management in the Internet of Things. We provide ­scenarios to illustrate the new world that will be produced by the Internet of Things, where physical objects are fully integrated into the information highway. We discuss the different types of data that will be part of the Internet of Things. These include identification, positional, environmental, historical, and descriptive data. We consider the challenges brought by the need to manage vast quantities of data across heterogeneous systems. In particular, we consider the areas of querying, indexing, process modeling, transaction handling, and integration of heterogeneous systems. We refer to the earlier work that might provide solutions for these challenges. Finally we discuss a road map for the Internet of Things and respective technical priorities.

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This paper presents various configurations of voltage source converter (VSC) based voltage regulators (VRs) for a stand alone power generation employing an isolated asynchronous generator (IAG). A set of VRs are designed and their performance is simulated using Simulink and Power System Blockset (PSB) ­toolboxes to demonstrate their capabilities as a voltage regulator, a harmonic eliminator, a load balancer and a neutral current compensator. It also discusses their merits and demerits, to select a suitable topology of the voltage regulator according to IAG system requirements.

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Handover (HO) mechanism is one of the critical operations in mobile WiMAX. It takes place when a mobile ­station (MS) moves from a serving base station (BS) to another BS. However, the HO latency in mobile WiMAX is still an issue that may affect continuity of real-time application sessions such as Voice over Internet Protocol (VoIP). This paper presents performance comparison of some HO mechanisms for real-time applications in mobile WiMAX, including HO, cross-layer HO, pre-coordination HO, passport HO mechanisms and fast intra-network and cross-layer HO (FINCH). Each one of these mechanisms reduces HO latency, especially during downlink traffic; however, they still produce insufficient HO latency during uplink traffic. Except for FINCH, they do not consider the scenario of HO between BSs that belong to different access service network-gateways (ASN-GWs) or to different connectivity service networks (CSNs); these two cases cause extra layer 3 (L3) HO latency.

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Speaker recognition system may be viewed as working in four stages, namely, analysis, feature extraction, modeling and testing. This paper gives an overview of the major techniques developed in each of these stages. Such a review helps in understanding the developments that have taken place in each stage and also the available choices of techniques, along with their relative merits and demerits. A comparative study of different techniques is done at the end of each section to justify the choice of techniques available in the state-of-the-art speaker recognition systems. The paper is concluded with a discussion on the possible future direction for the development of techniques in each stage.

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Multihop wireless networks have emerged recently as an evolution of wireless network technology and are likely to be the integral part of future communication environment. In this context, support for ­quality of service (QoS) is becoming an inherent necessity rather than an additional feature of the network. This paper presents a route stability-based multipath QoS routing protocol for mobile ad hoc networks to support throughput and delay sensitive real-time applications in these networks. We incorporate a hop-by-hop admission control and a soft resource reservation scheme in a route discovery process to ensure QoS ­assurance to real-time applications. Further, a simple route stability model is utilized during both route ­discovery and maintenance phases for selecting QoS routes with higher stability. The reliability of the multiple QoS routes is improved through node disjointness and stability properties of the discovered routes. Following an ­effective QoS ­violation detection and route maintenance mechanism, the protocol reduces the frequency of route recovery leading to a significant reduction in QoS disruption. Extensive simulation studies show that the proposed routing protocol can support higher level of QoS in terms of packet delivery ratio, average end-to-end delay, maximum jitter, and overall network throughput.

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This paper presents fingerprint biometric-based self-authentication and deniable authentication schemes, which enable a receiver to identify source of the message but not to prove the identity of the sender to a third party. At first, we identify the security flaws of some recently proposed deniable authentication schemes by three application scenarios, and prove that those schemes are vulnerable to impersonation and eavesdropping attacks. For remedy, we propose two-factor-based self-authentication and deniable authentication schemes in which, firstly, each user has to perform self-authentication by something he knows (password) and something he is (biometrics), and then he can accomplish the transaction, e.g., e-commerce. Security analysis shows that the proposed schemes can overcome the security pitfalls of the previous schemes and are secure, reliable and practicable with high potential to be used in the electronic world.

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This is a review paper on the topic of multiple gate field effect transistors: MuGFETs, or FinFETs, as they are called. First, the motivation behind multiple gate FETs is presented. This is followed by looking at the evolution of FinFET technologies; the main flavors (variants) of multigate FETs; and their advantages/disadvantages. The physics and technology of these devices is briefly discussed. Results are then presented which show the performance figures of merit of FinFETs, and their strengths and weaknesses. Finally, a perspective on the future of the FinFET technology is presented. This paper is a judicious mix of the author's original work on FinFETs and other contemporary know-how available in the literature on this topic.

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Wireless mesh networks is a new emerging field with its potential applications in extremely unpredictable and dynamic environments. However, it is particularly vulnerable due to its features of open medium, dynamic changing topology, and cooperative routing algorithms. The article surveys the state of the art in security for wireless mesh networks. First, we analyze various possible threats to security in wireless mesh networks. Second, we introduce some representative solutions to these threats, including solutions to the problems of key management, secure network routing, and intrusion detection. We also provide a comparison and discussion of their respective merits and drawbacks, and propose some improvements for these drawbacks. Finally, we also discuss the remaining challenges in the area.

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Energy efficient data transfer is the key factor for the design of energy efficient wireless sensor network (WSN). In this paper, an energy efficient cooperative MIMO (C-MIMO) technique is proposed in the WSN where fixed constellation size is considered in transmitting both the local and long-haul communication. A selection criterion is used based on the channel conditions where a selected number of sensors in a cluster is used to form a multiple input multiple output (MIMO) structure wirelessly connected with multiple antennas of a data gathering node (DGN). The selected approach is tested on the correlated data scenario. Experimental results show that the selected C-MIMO structure outperforms the unselected C-MIMO in terms of total energy consumption and they show energy efficient performance over existing one when they are compared with SISO structure. Energy models are evaluated for this scenario while energy consumption and efficiency are compared for different combination of cluster sizes and selected number of sensors. Comparisons are shown for different fixed number of constellation sizes. The effect of correlation coefficient and intersensor distance are analyzed. Later, a delay analysis is shown considering optimal constellation size.

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While many academic libraries are increasingly providing e­book services, a barrier to the adoption of e­books, however, is their unsatisfactory design. This paper reports on a study that investigates the students' preferences for the e­book designs, in an attempt to review what appeals to them in an ideal e­book. Comparison was made between three e­books in portable document format, all of which were non­fiction, but differed in contents and their styles of presentation. Based on the preliminary findings, some general guidelines were suggested for the improved design of e­books.

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Web caching has been used extensively to enhance content delivery to the clients by minimizing ­client- ­observed latency, reducing network bandwidth usage and improving scalability of the network. Caching performance can be improved by designing good replacement policies, prefetching techniques, clustering of web users and proper placement of proxy caches in the network. In this paper, we discuss the various approaches that were designed based on neural networks, genetic algorithms and fuzzy logic to optimize the performance of web caching. The approaches discussed here proved to be more effective in solving the problems as compared to the conventional techniques that were used earlier in this problem domain. Neural networks and evolutionary algorithms can be considered for further exploration in the various issues related to web caching and content delivery.

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Nowadays many different types of networks communicate among themselves to form heterogeneous ­networks. Vertical handovers between them are required to supply ongoing internet access to mobile nodes who switch from one coverage area to another with different characteristics. Mobility management techniques between heterogeneous network are necessary to reduce latency time and professionally treat the insufficient radio access resources to indemnity specific quality of service. This paper reviews literatures that are related to minimizing a ­vertical ­handover in heterogeneous wireless networks. This paper reviews literatures that are related to minimizing a vertical handover in heterogeneous wireless networks. This review investigated various handover management technologies for providing pure mobility between different access techniques such as GPRS, UMTS, and WI-FI. More of these solutions used mobile IP (MIP), transmission control protocol (TCP), stream control transmission protocol (SCTP) and session initiation protocol (SIP) to support integration between WLAN and UMTS. From the review we conclude that SCTP is much more robust against packet loss and delay ­compared to TCP, SIP, and MIP. This fact makes SCTP a potential scheme for heterogeneous wireless networks.

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In this paper, the effect of carrier frequency offset on a network where multiple independent devices cooperate to form virtual multiple input multiple output networks is analyzed. The common phase error and inter-carrier interference effect on Cooperative Alamouti space-time code orthogonal frequency division multiplexing system due to carrier frequency offset is investigated.

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Stopband filters are designed by etching periodic patterns of complementary split ring resonators (CSRRs) in the ground plane of a microstrip line. CSRRs, being sub-wavelength resonators, their size are much more smaller than the conventional microstrip resonators. As a resonator, it has been observed that a single CSRR in the ground plane has a very high Q factor and gives a very high rejection in the stopband. It has also been observed that the period of the CSRR loaded microstrip line can be made as small as 1/10 of the operating wavelength thereby extensive size miniaturization is possible. With the increased number of CSRRs etching and decreased period of the periodic structure loaded with CSRRs in the ground plane of the microstrip line, the stop bandwidth increases and side by side the rejection level in the mid stopband frequency increases significantly thereby further enhancing the stopband filter performance along with the extensive size miniaturization. A CSRR-stub filter has been proposed for harmonic suppression of microstrip filters and it has been used successfully for harmonic suppression of stepped impedance low pass filters.

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In fourth generation (4G) wireless networks and beyond, it is strongly anticipated that mobile ad hoc network will be used to economically extend their coverage and capacity. The mobile ad hoc networks provide new applications, but also face significant technical challenges. Recently, it has been argued that layered architectures are not suitable for wireless networks. In an effort to improve the performance of mobile ad hoc networks, there has been increased interest in protocols that rely on cross-layer interactions between different layers. In this paper, we proposed and studied three cross-layer designs among physical, medium access control and routing (network) layers, using Received Signal Strength (RSS) as cross-layer interaction parameter for energy conservation, unidirectional link rejection and reliable route formation in mobile ad hoc networks. These proposed cross-layer designs are implemented using GloMoSim, the Global Mobile Simulator, and the performance of cross-layer protocol frame work is studied.

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This paper presents techniques adopted to defend against Sybil Attack in Mobile Ad Hoc Networks. Sybil attack and the existing defense mechanisms against this type of attack have been reviewed and their loopholes are indicated. Multifactor Authentication Scheme has been discussed pointing out its superiority over traditional Cryptography-based Authentication Schemes. Afterwards, Passive Ad Hoc Sybil Identity Detection techniques differentiating a Sybil attacker from a group of legitimate nodes moving together is also discussed. Merits and demerits of these methods are mentioned and also the scopes for future research to improve these detection schemes have been indicated.

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Human exploration and development of space is aimed at opening the space frontier by exploring, using, and enabling the development of space and expanding the human experience into the far reaches of space. This includes increasing human knowledge of nature's processes using the space environment, exploring and settling the solar system, achieving routine space travel, and enriching life on Earth through people living and working in space. NASA's Mars robotic explorations and the International Space Station provide extensive experience, research and technology (R&T), and infrastructure for other envisioned programs in support of human exploration and development of space. The missions to Moon by United States, Russia, China, India, and Japan have provided valuable data for the Moon. In addition, NASA has studied the development of a lunar habitat and human mission to Mars as possible future missions. These missions face common challenges of travel to these planets and for the survival of humans on the surface of the planets. With the human Mars mission being the first to such a distant planet, advanced technologies will be required to enable the mission and to provide cost effective and safer approaches. The R&T areas considered important for future human mission include advanced human support, renewable resources and utilization of planetary resources, space transportation, automation and robotics, space power, information processing and communications systems, sensors, and instruments.

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Traditional database research has developed technology to ensure that the database - even when ­distributed - represents the world of interest with integrity and a consistent state. Important concepts have been developed and proven. However, the internet of things challenges all this. Very large numbers of nodes handle volumes that are vast, the speed is fast and the data/information space is global - indeed with space data - universal. This poses challenges. What does the concept of a state mean when the ­information map of the real world of interest is represented across millions of nodes, many of which are updating in real-time? What does a transaction look like when the data being updated is spread across ­hundreds or thousands of nodes with differing update policies? Worse, how does one roll back or ­compensate a ­transaction? We have ­already seen database research applied to semi-structured data, to streamed data, and real-time ­applications. Is it possible for these techniques to be applied to the internet of things? The internet of things opens up more opportunities for security compromises. How do we develop trust band security techniques across multiple policies? How do we prevent the unauthorized use of private information yet permit ­authorized use? We need dynamic trust, security, and privacy management. Do we need a new theoretical framework?

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