A Perspective Review of Security Challenges in Body Area Networks for Healthcare Applications

International Journal of Wireless Information Networks - Body area network (BAN) connects sensors and actuators to the human body in order to collect patient’s information and transmitting it...     

Free-Space Optical Communications for Next-generation Military Networks

There is a continuing need for increased capacity for military applications, especially in network-centric operational concepts that promote the use of information as fundamental for gaining superiority on the battlefield. As an example, the access to, and distribution of, sensor data is a major tenet of network-centric warfare and yet radio frequency (RF) links will struggle to provide the needed capacity. Free-space optical communications (FSOC) has the potential to meet these emerging military needs by offering dramatic increases in capacity. However, there are many technical challenges al multiple layers of the communications protocol stack. This article describes these challenges and discusses some mitigation approaches to provide a path to realizing this capability on the battlefield     

Mobility Management UAV-based Grouping routing protocol in flying ad hoc networks for biomedical applications

Wireless body area networks play a vital role in the medical field by saving human lives. It senses the human body condition and transmits it to the respective doctors. The faster the communication, the sensed data can be transmitted faster and the patients in emergency can be treated on time. Therefore, to increase the speed of communication, Unmanned Aerial Vehicles (UAV) are used in biomedical applications. In this flying ad hoc network, there is a possibility of link failure due to the high mobility of UAV. To overcome this issue, a new routing protocol, Mobility Management UAV-based Grouping (MMUG), for biomedical data transmission from one ground station to another via UAV is suggested in this research. The UAV creates the grouping system based on the coverage range of the group head. Group head selects the node that lies closer to the ground station. Group head continuously monitors the mobility of the unmanned aerial vehicles that lie in the coverage range and thus helps to maintain the link stability. The mobility issue will be overcome by using this proposed scheme, and it manages the mobility. The mobility management helps to increase the network performance by increasing the delivery rate and throughput and reducing the drop rate and overhead. Simulation results show that this routing protocol achieves 86% delivery rate and 1.95 Mbps throughput and reduces the drop rate by 14%, control overhead by 23%, and routing overhead by 20%. Moreover, this model achieves higher network performance compared to the existing techniques.     

Bioactivity and emerging role of short and medium chain fatty acids

Cardiovascular disease (CVD) and insulin resistance are directly linked to overweight and obesity. Thus, any dietary strategy capable of causing weight reduction will lower CVD and diabetes risk. Oils rich in medium‐chain saturated fatty acids (MCFA) are among several dietary components that may have potential in the treatment of obesity. MCFA are less energy dense and highly ketogenic compared to long‐chain saturated and unsaturated fatty acids (LCFA). MCFA also differ from LCFA in their digestive and metabolic pathways, since they are easily oxidized and utilized as energy, with little tendency to deposit as body fat. The dietary intake of short (SCFA) and medium‐chain saturated fatty acids from natural food sources is approximately 2.4 g/day and accounts for about 9% of the total saturated fatty acid (SFA) intake. Although early clinical studies with high levels of MCFA resulted in increased levels of plasma triacylglycerols (TAG) and low‐density lipoprotein cholesterol (LDL‐C), and reduced levels of high‐density lipoprotein cholesterol (HDL‐C) compared to diets enriched in unsaturated LCFA, these adverse effects have not been observed in more recent studies with smaller more realistic amounts of MCFA. The lower caloric value of SCFA and MCFA and their unique metabolic features form the basis for their clinical use in enteral and parenteral nutrition and for novel reduced calorie lipids for use in conventional food products.     

Mobile small aperture satellite terminals for military communications

The United States Army is currently developing a satellite-based network-centric waveform. Mobile terminals that are small and compact are highly desirable for the military. This article gives an overview of the technical challenges and performance issues when mobile small aperture satellite terminals are connected to a network- centric communication system. The specific issues addressed are regulatory limits on off-axis emissions, performance of small aperture terminals in the presence of adjacent satellite interference, and the effects of motion induced antenna pointing errors on the satellite communication system.     

Dual-mode type algorithms for blind equalization

Adaptive channel equalization accomplished without resorting to a training sequence is known as blind equalization. The Godard algorithm and the generalized Sato algorithm are two widely referenced algorithms for blind equalization of a QAM system. These algorithms exhibit very slow convergence rates when compared to algorithms employed in conventional data-aided equalization schemes. In order to speed up the convergence process, these algorithms may be switched over to a decision-directed equalization scheme once the error level is reasonably low. The authors present a scheme which is capable of operating in two modes: blind equalization mode and a mode similar to the decision-directed equalization mode. In this proposed scheme, the dominant mode of operation changes from the blind equalization mode at higher error levels to the mode similar to the decision-directed equalization mode at lower error levels. Manual switch-over to the decision-directed mode from the blind equalization mode, or vice-versa, is not necessary since transitions between the two modes take place smoothly and automatically     

Effect of Time Diversity on the Forward Link of the DS-CDMA Cellular System

A direct-sequences code division multiple access system has been accepted as a digital cellular standard (IS–95) in North America [1]. This digital cellular standard employs a powerful rate 1/2, constraint length 9, convolutional code in its forward link. It is well-known that in a Rayleigh fading channel the performance of a channel code depends very heavily on the interleaving depth and the relative variations of the channel characteristics. In slow fading channels, since the input symbols to the channel decoder are highly correlated, the bit-error-rate at the output of the channel decoder may be unacceptably high. Interleavers of large dimensions can reduce the correlation of the input signal to the channel decoder at the expense of an intolerable delay. In this paper we examine the performance of the IS–95 system, at the mobile receiver, for different channel fade rates. Also, we present a simple time diversity technique which employs multiple receive antennas. The multiple receive antennas in this case generate a fast fading effect and thus improves the performance of the channel decoder significantly.     

Accumulative-DSIF strategy for enhancing process capabilities in incremental forming

This work proposes a novel Accumulative Double Sided Incremental Forming (ADSIF) strategy in which the forming begins at the location of the deepest feature and gradually shapes up the features by taking advantage of rigid-body motions. Compared to the conventional toolpath used in DSIF and SPIF, this strategy can dramatically improve geometric accuracy, increase formability, form components with desired thickness and create complex components. Furthermore, an examination of the forming forces shows that the dominant forces using this strategy are in the plane of the sheet resulting in a significant improvement in geometric accuracy.     

An error-protected speech recognition system for wirelesscommunications

Future wireless multimedia terminals will have a variety of applications that require speech recognition capabilities. We consider a robust distributed speech recognition system where representative parameters of the speech signal are extracted at the wireless terminal and transmitted to a centralized automatic speech recognition (ASR) server. We propose two unequal error protection schemes for the ASR bit stream and demonstrate the satisfactory performance of these schemes for typical wireless cellular channels. In addition, a "soft-feature" error concealment strategy is introduced at the ASR server that uses "soft-outputs" from the channel decoder to compute the marginal distribution of only the reliable features during likelihood computation at the speech recognizer. This soft-feature error concealment technique reduces the ASR error rate by more than a factor of 2.5 for certain channels. Also considered is a channel decoding technique with source information that improves ASR performance     

FEC scheme for a TDM-OFDM based satellite radio broadcasting system

There are two licenses, 12.5 MHz each, in the S-band for digital satellite-to-vehicle radio broadcasting in the United States. The potential advantages of such a system is that a motorist can enjoy commercial-free music, digital-quality sound and seamless coast-to-coast coverage. One proposal for the broadcast system is to have two satellites covering the continental USA at any given time. There will also be terrestrial repeaters in cities where the receivers on the vehicles cannot see the two satellites. The channels of these systems are affected by Rician, Rayleigh and flat fading caused by shadowing. This paper proposes a forward error correction (FEC) scheme that is not only robust against fading but also enables a low-delay tuning channel so that minimum tuning delay will occur when a user is switching and selecting programs. The scheme uses multiple source coded bit streams employing different interleaver depths. Large interleavers are used to ensure good decoded signal quality while small interleavers are used to minimize tuning delay. The proposed scheme also ensures that a program will not be interrupted by momentary shadowing frequently experienced by a motorist when, for example, a vehicle goes under a highway overpass. The impact of interleaver design on the real-time end-to-end delay and fading due to shadowing is analyzed. Finally, the channel code performance in Rician and Rayleigh fading channels are also presented