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Communications and Networks, Journal of

Issue 2 • Date April 2011

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Displaying Results 1 - 21 of 21
  • [Front cover]

    Page(s): c1
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  • [Inside front cover]

    Page(s): c2
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  • Emerging technologies and applications of wireless communication in healthcare

    Page(s): 81 - 85
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (150 KB) |  | HTML iconHTML  

    Future healthcare systems are anticipated to offer high quality services to patients with low costs through a variety of applications enabled by wireless and information technologies. This is because these wireless-equipped healthcare systems can remotely and continuously monitor the patients' health status in both residential settings and outdoor settings, where patients feel more comfortable and their activities are less restricted. Early detection of patients' emergency situations via wireless communications makes it possible to provide timely first-aid and access to patients' health information in a pervasive manner, thereby improving both system reliability and efficiency. Although huge potential benefits are widely recognized, the application of wireless communication technologies in healthcare systems brings more challenging issues including energy-efficiency, quality-of-services (QoS), definition of healthcare policy, design of healthcare architectures, emergency detection and response, security and privacy, and legal issues. View full abstract»

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  • Development of a WLAN based monitoring system for group activity measurement in real-time

    Page(s): 86 - 94
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2207 KB) |  | HTML iconHTML  

    In recent years, there has been a rise in epidemiological evidence suggesting the health benefits of a physically active lifestyle. However, it is not always easy for individuals to personally recognize the optimal conditions for exercise and physical activity. Wearable acceleration-based pedometers have become widely used in estimating the amount of physical activity, and to a limited ex tent, providing information regarding exercise intensity, but they have never been used to assess adaptation to exercise. In order to realize simultaneous activity monitoring for multiple users exercising outdoors, we developed a prototype wireless local area net work (WLAN) based system. In our system, a WLAN is deployed outside, and a user wearing a smart phone and monitoring device exercises freely within the coverage area of the wireless network. By doing so, the developed system is able to monitor the activity of each user and measures various parameters including those related to exercise adaptation. In a demonstration experiment, the developed system was evaluated and used to monitor users enjoying a Nordic walk, after which users were immediately able to receive their exercise report. In this paper, we discuss the requirements and issues in developing an activity monitoring system and report the findings we obtained through the demonstration experiment. View full abstract»

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  • Supporting context-aware applications for eldercare

    Page(s): 95 - 101
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (922 KB) |  | HTML iconHTML  

    Extended life expectancy and a decrease in fertility rates are dramatically increasing the number of seniors who will eventually need professional care assistance. Although there is no clear technical solution to this problem, recent advances in ubiquitous computing offer opportunities to assist elders in their residence, thus reducing the need for professional assistance in special facilities. There have been several studies, but current solutions tend to address specific issues and cannot be easily extended, updated, and customized to meet the complex and evolving requirements of eldercare assistance. This study aims to bridge this gap, and this pa- per presents a context-management framework, called awareness for pervasive environments (APE), that provides easily customizable support for the development of ubiquitous eldercare services and applications. View full abstract»

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  • PEC: A privacy-preserving emergency call scheme for mobile healthcare social networks

    Page(s): 102 - 112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1397 KB) |  | HTML iconHTML  

    In this paper, we propose a privacy-preserving emergency call scheme, called PEC, enabling patients in life-threatening emergencies to fast and accurately transmit emergency data to the nearby helpers via mobile healthcare social networks (MHSNs). Once an emergency happens, the personal digital assistant (PDA) of the patient runs the PEC to collect the emergency data including emergency location, patient health record, as well as patient physiological condition. The PEC then generates an emergency call with the emergency data inside and epidemically disseminates it to every user in the patient's neighborhood. If a physician happens to be nearby, the PEC ensures the time used to notify the physician of the emergency is the shortest. We show via theoretical analysis that the PEC is able to provide fine-grained access control on the emergency data, where the access policy is set by patients themselves. More- over, the PEC can withstand multiple types of attacks, such as identity theft attack, forgery attack, and collusion attack. We also de- vise an effective revocation mechanism to make the revocable PEC (rPEC) resistant to inside attacks. In addition, we demonstrate via simulation that the PEC can significantly reduce the response time of emergency care in MHSNs. View full abstract»

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  • Wireless three-pad ECG system: Challenges, design, and evaluations

    Page(s): 113 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2690 KB) |  | HTML iconHTML  

    Electrocardiography (ECG) is a widely accepted approach for monitoring of cardiac activity and clinical diagnosis of heart diseases. Since cardiologists have been well-trained to accept 12-lead ECG information, a huge number of ECG systems are using such number of electrodes and placement configuration to facilitate fast interpretation. Our goal is to design a wireless ECG system which renders conventional 12-lead ECG information. We pro pose the three-pad ECG system (W3ECG). W3ECG furthers the pad design idea of the single-pad approach. Signals obtained from these three pads, plus their placement information, make it possible to synthesize conventional 12-lead ECG signals. We provide one example of pad placement and evaluate its performance by examining ECG data of four patients available from online database. Feasibility test of our selected pad placement positions show comparable results with respect to the EASI lead system. Experimental results also exhibit high correlations between synthesized and directly observed 12-lead signals (9 out of 12 cross-correlation coefficients higher than 0.75). View full abstract»

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  • Automatic detection of anomalies in blood glucose using a machine learning approach

    Page(s): 125 - 131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (817 KB) |  | HTML iconHTML  

    Rapid strides are being made to bring to reality the technology of wearable sensors for monitoring patients' physiological data. We study the problem of automatically detecting anomalies in the measured blood glucose levels. The normal daily measurements of the patient are used to train a hidden Markov model (HMM). The structure of the HMM-its states and output symbols-are selected to accurately model the typical transitions in blood glucose levels throughout a 24-hour period. The learning of the HMM is done using historic data of normal measurements. The HMM can then be used to detect anomalies in blood glucose levels being measured, if the inferred likelihood of the observed data is low in the world described by the HMM. Our simulation results show that our technique is accurate in detecting anomalies in glucose levels and is robust (i.e., no false positives) in the presence of reasonable changes in the patient's daily routine. View full abstract»

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  • Exploring the feasibility of differentiating IEEE 802.15.4 networks to support health-care systems

    Page(s): 132 - 141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2105 KB) |  | HTML iconHTML  

    IEEE 802.15.4 networks are a feasible platform candidate for connecting all health-care-related equipment dispersed across a hospital room to collect critical time-sensitive data about patient health state, such as the heart rate and blood pressure. To meet the quality of service requirements of health-care systems, this paper proposes a multi-priority queue system that differentiates between various types of frames. The effect of the proposed system on the average delay and throughput is explored herein. By employing different contention window parameters, as in IEEE 802.11e, this multi-queue system prioritizes frames on the basis of priority classes. Performance under both saturated and unsaturated traffic conditions was evaluated using a novel analytical model that comprehensively integrates two legacy models for 802.15.4 and 802.11e. To improve the accuracy, our model also accommodates the transmission retries and deferment algorithms that significantly affect the performance of IEEE 802.15.4. The multi-queue scheme is predicted to separate the average delay and throughput of two different classes by up to 48.4 % and 46 %, respectively, without wasting bandwidth. These outcomes imply that the multi-queue system should be employed in health-care systems for prompt allocation of synchronous channels and faster delivery of urgent information. The simulation results validate these model's predictions with a maximum deviation of 7.6%. View full abstract»

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  • IEEE 802.15.6 under saturation: Some problems to be expected

    Page(s): 142 - 148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (881 KB) |  | HTML iconHTML  

    Because currently available wireless technologies are not appropriate for wireless body area networks (WBANs), the IEEE 802.15.6 standard was introduced by the IEEE 802.15.6 Task Group to satisfy all the requirements for a monitoring system that operates on, in, or around the human body. In this work, we develop an analytical model for evaluating the performance of an IEEE 802.15.6-based WBAN under saturation condition and a noisy channel. We employ a three-dimensional Markov chain to model the backoff procedure as specified in the standard. Probability generating functions (PGFs) are used to compute the performance descriptors of the network. The results obtained from the analytical model are validated by simulation results. Our results indicate that under saturation condition, the medium is accessed by the highest user priority nodes at the vast majority of time while the other nodes are starving. View full abstract»

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  • Wireless LAN with medical-grade QoS for e-healthcare

    Page(s): 149 - 159
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1318 KB) |  | HTML iconHTML  

    In this paper, we study the problem of how to design a medical-grade wireless local area network (WLAN) for healthcare facilities. First, unlike the IEEE 802.11e MAC, which categorizes traffic primarily by their delay constraints, we prioritize medical applications according to their medical urgency. Second, we propose a mechanism that can guarantee absolute priority to each traffic category, which is critical for medical-grade quality of service (QoS), while the conventional 802.11e MAC only provides relative priority to each traffic category. Based on absolute priority, we focus on the performance of real-time patient monitoring applications, and derive the optimal contention window size that can significantly improve the throughput performance. Finally, for proper performance evaluation from a medical viewpoint, we introduce the weighted diagnostic distortion (WDD) as a medical QoS metric to effectively measure the medical diagnosability by extracting the main diagnostic features of medical signal. Our simulation result shows that the proposed mechanism, together with medical categorization using absolute priority, can significantly improve the medical-grade QoS performance over the conventional IEEE 802.11e MAC. View full abstract»

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  • Packet-level scheduling for implant communications using forward error correction in an erasure correction mode for reliable u-healthcare service

    Page(s): 160 - 166
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (742 KB) |  | HTML iconHTML  

    In u-healthcare services based on wireless body sensor networks, reliable connection is very important as many types of information, including vital signals, are transmitted through the networks. The transmit power requirements are very stringent in the case of in-body networks for implant communication. Further- more, the wireless link in an in-body environment has a high degree of path loss (e.g., the path loss exponent is around 6.2 for deep tissue). Because of such inherently bad settings of the communication nodes, a multi-hop network topology is preferred in order to meet the transmit power requirements and to increase the battery lifetime of sensor nodes. This will ensure that the live body of a patient receiving the healthcare service has a reduced level of specific absorption ratio (SAR) when exposed to long-lasting radiation. We propose an efficient method for delivering delay-intolerant data packets over multiple hops. We consider forward error correction (FEC) in an erasure correction mode and develop a mathematical formulation for packet-level scheduling of delay-intolerant FEC packets over multiple hops. The proposed method can be used as a simple guideline for applications to setting up a topology for a medical body sensor network of each individual patient, which is connected to a remote server for u-healthcare service applications. View full abstract»

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  • Efficient interference cancellation scheme for wireless body area network

    Page(s): 167 - 174
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1135 KB) |  | HTML iconHTML  

    In this paper, we propose and simulate an efficient interference cancellation scheme with an optimal ordering successive interference cancellation (SIC) algorithm for ultra wideband (UWB)/multiple-input-multiple-output (MIMO) systems in a wire- less body area network (WBAN). When there are several wireless communication devices on a human body, multiple access interference (MAI) usually occurs. To mitigate the effect of MAI and achieve additional diversity gain, we utilize SIC with an optimal ordering algorithm. A zero correlation duration (ZCD) code with robust MAI capability is employed as a spread code for UWB systems in a multi-device WBAN environment. The performance of the proposed scheme is evaluated in terms of the bit error rate (BER). Simulation results confirm that the BER performance can be improved significantly if the proposed interference cancellation scheme and the ZCD code are jointly employed. View full abstract»

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  • Access right assignment mechanisms for secure home networks

    Page(s): 175 - 186
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1377 KB) |  | HTML iconHTML  

    The proliferation of advanced technologies has been altering our lifestyle and social interactions-the next frontier is the digital home. Although the future of smart homes is promising, many technical challenges must be addressed to achieve convenience and security. In this paper, we delineate the unique combination of security challenges specifically for access control and consider the challenges of how to simply and securely assign access control policies to visitors for home devices and resources. We present a set of intuitive access control policies and suggest four access control settings based on our in-person interview results. Furthermore, we propose the automated Clairvoyant access right assignment (CARA) mechanism that utilizes home owners' social relationship to automatically deduce to which class a visitor belongs. The combination of CARA and the suggested mapping provides a promising first step for home policy assignment such that non-expert home owners can let visitors use their home network with confidence. We anticipate that future research can build on our proposed mechanisms to provide confidence to non-expert home owners for letting visitors use their home network. View full abstract»

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  • SplitScreen: Enabling efficient, distributed malware detection

    Page(s): 187 - 200
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1727 KB) |  | HTML iconHTML  

    We present the design and implementation of a novel anti-malware system called SplitScreen. SplitScreen performs an additional screening step prior to the signature matching phase found in existing approaches. The screening step filters out most non-infected files (90%) and also identifies malware signatures that are not of interest (99%). The screening step significantly improves end-to-end performance because safe files are quickly identified and are not processed further, and malware files can subsequently be scanned using only the signatures that are necessary. Our approach naturally leads to a network-based anti-malware solution in which clients only receive signatures they needed, not every malware signature ever created as with current approaches. We have implemented SplitScreen as an extension to ClamAV, the most popular open source anti-malware software. For the current number of signatures, our implementation is 2x faster and requires 2x less memory than the original ClamAV. These gaps widen as the number of signatures grows. View full abstract»

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  • Call for papers

    Page(s): 1
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  • Call for papers

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  • Call for papers

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  • [Advertisement]

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  • [Back inside cover]

    Page(s): c3
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  • [Back cover]

    Page(s): c4
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Aims & Scope

The Journal of Communications and Networks is published six times per year, and is committed to publishing high-quality papers that advance the state-of-the-art and practical applications of communications and information networks.

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Meet Our Editors

Editor-in-Chief
H. Vincent Poor
Princeton University