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Emmanuel O. Agu

Articles 1 - 10 of 10

Full-Text Articles in Physical Sciences and Mathematics

The Effect Of Latency On User Performance In Warcraft Iii, Nathan Sledon, Eric Girard, Seth Borg, Mark Claypool, Emmanuel Agu Dec 2015

The Effect Of Latency On User Performance In Warcraft Iii, Nathan Sledon, Eric Girard, Seth Borg, Mark Claypool, Emmanuel Agu

Emmanuel O. Agu

Variable latency on the Internet is a well-known problem for interactive applications. With the increase in interactive network games comes the increased importance of understanding the effects of latency on user performance. Classes of network games such as First Person Shooters (FPS) and Read Time Strategy (RTS) differ in their user interaction model and hence susceptibility to variable latency. While previous work has measured the effects of latency on FPS games, there has been no systematic investigation of the effects of latency on RTS games. In this work, we design and conduct user studies that measure the impact of latency …

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Low Delay Marking For Tcp In Wireless Ad Hoc Networks, Choong-Soo Lee, Mingzhe Li, Emmanuel Agu, Mark Claypool, Robert Kinicki Dec 2015

Low Delay Marking For Tcp In Wireless Ad Hoc Networks, Choong-Soo Lee, Mingzhe Li, Emmanuel Agu, Mark Claypool, Robert Kinicki

Emmanuel O. Agu

End-hosts on wireless ad hoc networks typically use TCP as their transport layer protocol. Being designed for wired networks, TCP can perform poorly over wireless networks. Work that has proposed ways to improve TCP performance over wireless networks has concentrated primarily on improving TCP throughput only. Emerging applications, such as interactive multimedia and network games, require reduced delay at least as much as increased throughput. In this paper, we propose LDM1, an IP layer queue marking mechanism that estimates the number of hops and flows at each wireless node to computes the optimal marking probability. We present simulation results and …

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Time-Partitioned Index Design For Adaptive Multi-Route Data Stream Systems Utilizing Heavy Hitter Algorithms, Karen Works, Elke Rundensteiner, Emmanuel Agu Dec 2015

Time-Partitioned Index Design For Adaptive Multi-Route Data Stream Systems Utilizing Heavy Hitter Algorithms, Karen Works, Elke Rundensteiner, Emmanuel Agu

Emmanuel O. Agu

Adaptive multi-route query processing (AMR) is a recently emerging paradigm for processing stream queries in highly fluctuating environments. AMR dynamically routes batches of tuples to operators in the query network based on routing criteria and up-to-date system statistics. In the context of AMR systems, indexing, a core technology for efficient stream processing, has received little attention. Indexing in AMR systems is demanding as indices must adapt to serve continuously evolving query paths while maintaining index content under high volumes of data. Our proposed Adaptive Multi-Route Index (AMRI) employs a bitmap time-partitioned design that while being versatile in serving a diverse …

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Performance Enhancement Of Tfrc In Wireless Networks, Mingzhe Li, Emmanuel Agu, Mark Claypool, Robert Kinicki Dec 2015

Performance Enhancement Of Tfrc In Wireless Networks, Mingzhe Li, Emmanuel Agu, Mark Claypool, Robert Kinicki

Emmanuel O. Agu

The TCP-Friendly Rate Control (TFRC) is used as a streaming media transport protocol. Using the TCP congestion response function and current network conditions, TFRC adjusts its transmission rate to yield the maximum TCP-Friendly throughput when sharing capacity with TCP flows. Since TFRC was designed for wired networks, it does not achieve the maximum TCP-Friendly throughput in multihop ad hoc wireless networks. The reduced wireless spatial channel reuse due to hidden terminals in multihop wireless networks induces TFRC throughput reductions. Specifically, TFRC is unaware of MAC layer transmission delays due to collisions, retransmissions and MAC layer congestion. This paper illustrates that …

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Measuring The Performance Gains From Directional Antennas In An Unplanned 802.11b Mesh Network, Jason Wilson, Patrick Gemme, Emmanuel Agu Dec 2015

Measuring The Performance Gains From Directional Antennas In An Unplanned 802.11b Mesh Network, Jason Wilson, Patrick Gemme, Emmanuel Agu

Emmanuel O. Agu

Wireless mesh networks are becoming increasingly popular. Most proposed mesh algorithms are evaluated using simulation. Simulations frequently oversimplify real world scenarios and can lead to results that are significantly different. Thus, although it is more difficult to run controlled experiments in already deployed real-world networks, it is important to understand how proposed improvements perform under these realistic scenarios. Several authors have suggested the use of directional antennas, but their merits have only comprehensively evaluated in simulators. Roofnet is an unplanned 802.11b wireless mesh network deployed by MIT and is constructed primarily of omni-directional antennas. We use measurements to evaluate performance …

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Tradeoffs Between Energy And Security In Wireless Networks, Fernando Colón Osorio, Emmanuel Agu, Kerry Mckay Dec 2015

Tradeoffs Between Energy And Security In Wireless Networks, Fernando Colón Osorio, Emmanuel Agu, Kerry Mckay

Emmanuel O. Agu

In recent years, several researchers have studied the vulnerabilities present in the encryption protocols and authentication mechanisms associated with 802.11-based networks. This research has led to the creation of protocol extensions and replacement proposals such as WPA, 802.11i, and 802.1X. In addition, Denial of Service attacks that can be launched against 802.11-based networks, with relative ease and impunity, have been studied. Simultaneously, researchers studying the limitations of wireless networks have turned their attention to one of the inherent limitation of wireless devices, namely, power consumption. Research in this area has been focused in understanding the impact of the network interface …

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Characterizing The Performance And Behaviors Of Runners Using Twitter, Qian He, Emmanuel Agu, Diane Strong, Bengisu Tulu, Peder Pedersen Dec 2015

Characterizing The Performance And Behaviors Of Runners Using Twitter, Qian He, Emmanuel Agu, Diane Strong, Bengisu Tulu, Peder Pedersen

Emmanuel O. Agu

Running is a popular physical activity that improves physical and mental wellbeing. Unfortunately, up-to- date information about runners’ performance and psychological wellbeing is limited. Many questions remain unanswered, such as how far and how fast runners typically run, their preferred running times and frequencies, how long new runners persist before dropping out, and what factors cause runners to quit. Without hard data, establishing patterns of runner behavior and mitigating the challenges they face are difficult. Collecting data manually from large numbers of runners for research studies is costly and time consuming. Emerging Social Networking Services (SNS) and fitness tracking devices …

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Detection Of Diabetic Foot Ulcers Using Svm Based Classification, Lei Wang, Peder Pedersen, Diane Strong, Bengisu Tulu, Emmanuel Agu, Qian He, Ronald Ignotz, Raymond Dunn, David Harlan, Sherry Pagoto Dec 2015

Detection Of Diabetic Foot Ulcers Using Svm Based Classification, Lei Wang, Peder Pedersen, Diane Strong, Bengisu Tulu, Emmanuel Agu, Qian He, Ronald Ignotz, Raymond Dunn, David Harlan, Sherry Pagoto

Emmanuel O. Agu

Diabetic foot ulcers represent a significant health issue, for both patients’ quality of life and healthcare system costs. Currently, wound care is mainly based on visual assessment of wound size, which suffers from lack of accuracy and consistency. Hence, a more quantitative and computer-based method is needed. Supervised machine learning based object recognition is an attractive option, using training sample images with boundaries labeled by experienced clinicians. We use forty sample images collected from the UMASS Wound Clinic by tracking 8 subjects over 6 months with a smartphone camera. To maintain a consistent imaging environment and facilitate the capture process …

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A Context-Aware Activity Recommendation Smartphone Application To Mitigate Sedentary Lifestyles, Qian He, Emmanuel Agu Dec 2015

A Context-Aware Activity Recommendation Smartphone Application To Mitigate Sedentary Lifestyles, Qian He, Emmanuel Agu

Emmanuel O. Agu

A sedentary lifestyle involves irregular or no physical activity. In this kind of lifestyle, people’s activities do not increase their energy expenditure substantially above resting levels. Long periods of sitting, lying, watching television, playing video games, and using the computer are typical examples. Energy expenditures at 1.0-1.5 Metabolic Equivalent Units (METs) are considered sedentary behaviors. A recent study of sedentary lifestyles found that the length of sedentary times is associated with an increased risk of diabetes, cardiovascular disease, and cardiovascular and all-cause mortality. In this study, we developed a smartphone application called “On11”, which continuously tracks and informs the user …

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The Effects Of Loss And Latency On User Performance In Unreal Tournament 2003, Tom Beigbeder, Rory Coughlan, Corey Lusher, John Plunkett, Emmanuel Agu, Mark Claypool Dec 2015

The Effects Of Loss And Latency On User Performance In Unreal Tournament 2003, Tom Beigbeder, Rory Coughlan, Corey Lusher, John Plunkett, Emmanuel Agu, Mark Claypool

Emmanuel O. Agu

With the growth in interactive network games comes an increased importance in a better understanding of the effects of latency on user performance. While previous work has studied the tolerance game players have for high latencies and has studied the effects of latency on user performance in real-time strategy games, to the best of our knowledge, there has been no systematic study of the effects of loss and latency on user performance. In this paper we study user performance for Unreal Tournament 2003 (UT2003), a popular FPS game, under varying amounts of latency and packet loss. First, we deduced typical …

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