Downstream Bandwidth Management for Emerging DOCSIS-based Networks

In this dissertation, we consider the downstream bandwidth management in the context of emerging DOCSIS-based cable networks. The latest DOCSIS 3.1 standard for cable access networks represents a significant change to cable networks. For downstream, the current 6 MHz channel size is replaced by a much larger 192 MHz channel which potentially can provide data rates up to 10 Gbps. Further, the current standard requires equipment to support a relatively new form of active queue management (AQM) referred to as delay-based AQM. Given that more than 50 million households (and climbing) use cable for Internet access, a clear understanding of the impacts of bandwidth management strategies used in these emerging networks is crucial. Further, given the scope of the change provided by emerging cable systems, now is the time to develop and introduce innovative new methods for managing bandwidth. With this motivation, we address research questions pertaining to next generation of cable access networks. The cable industry has had to deal with the problem of a small number of subscribers who utilize the majority of network resources. This problem will grow as access rates increase to gigabits per second. Fundamentally this is a problem on how to manage data flows in a fair manner and provide protection. A well known performance issue in the Internet, referred to as bufferbloat, has received significant attention recently. High throughput network flows need sufficiently large buffer to keep the pipe full and absorb occasional burstiness. Standard practice however has led to equipment offering very large unmanaged buffers that can result in sustained queue levels increasing packet latency. One reason why these problems continue to plague cable access networks is the desire for low complexity and easily explainable (to access network subscribers and to the Federal Communications Commission) bandwidth management. This research begins by evaluating modern delay-based AQM algorithms in downstream DOCSIS 3.0 environments with a focus on fairness and application performance capabilities of single queue AQMs. We are especially interested in delay-based AQM schemes that have been proposed to combat the bufferbloat problem. Our evaluation involves a variety of scenarios that include tiered services and application workloads. Based on our results, we show that in scenarios involving realistic workloads, modern delay-based AQMs can effectively mitigate bufferbloat. However they do not address the other problem related to managing the fairness. To address the combined problem of fairness and bufferbloat, we propose a novel approach to bandwidth management that provides a compromise among the conflicting requirements. We introduce a flow quantization method referred to as adaptive bandwidth binning where flows that are observed to consume similar levels of bandwidth are grouped together with the system managed through a hierarchical scheduler designed to approximate weighted fairness while addressing bufferbloat. Based on a simulation study that considers many system experimental parameters including workloads and network configurations, we provide evidence of the efficacy of the idea. Our results suggest that the scheme is able to provide long term fairness and low delay with a performance close to that of a reference approach based on fair queueing. A further contribution is our idea for replacing `tiered\u27 levels of service based on service rates with tiering based on weights. The application of our bandwidth binning scheme offers a timely and innovative alternative to broadband service that leverages the potential offered by emerging DOCSIS-based cable systems

KINEMATICAL CHARACTERISTICS OF BICYCLE KICK AND SIDE VOLLEY IN SOCCER

INTRODUCTION: There exist various techniques for successfully gaining goals: maximal instep kick, bicycling kick and/or side volley. However, due to test constraints, difficulty in multi-dimensional signal exploration and the complexity of total body control, there is hardly any scientific study that describes bicycle kick and side volley (Shan & Westerhoff, 2005). The current study tried to address this deficiency by 1) providing 3D kinematical characteristics of these two techniques using a 15-segmental full body model and 2) exploring possible parameters for quantitative evaluations of the kick quality

Challenges and Future of Wearable Technology in Human Motor-Skill Learning and Optimization

Learning how to move is a challenging task. Even the most basic motor skill of walking requires years to develop and can quickly deteriorate due to aging and sedentary lifestyles. More specialized skills such as ballet and acrobatic kicks in soccer require “talent” and years of extensive practice to fully master. These practices can easily cause injuries if conducted improperly. 3D motion capture technologies are currently the best way to acquire human motor skill in biomechanical feedback training. Owing to their tremendous promise for a plethora of applications, wearable technologies have garnered great interest in biofeedback training. Using wearable technology, some physical activity parameters can be tracked in real time and a noninvasive way to indicate the physical progress of a trainee. Yet, the application of biomechanical wearables in human motor-skill learning, training, and optimization is still in its infant phase due to the absence of a reliable method. This chapter elaborates challenges faced by developing wearable biomechanical feedback devices and forecasts potential breakthroughs in this area. The overarching goal is to foster interdisciplinary studies on wearable technology to improve how we move

HOW TOUGH IS IT TO REPEATEDLY HIT THE BALL IN GOLF?

Golf is an increasingly popular sport, whose most challenging skill is the driver swing. There have been a large number of studies characterizing golf swings, yielding insightful instructions on how to successfully structure the swing. Achieving a sub 18 handicap is no longer the primary concern for golfers. Instead, players are now most troubled by a lack of consistency during swing execution. The goal of this study is to determine how to consistently execute repeated quality golf swings. By characterizing both successful and failed swings of 22 experienced golfers, we aim to identify swing parameters that are most sensitive and/or prone to motor control variations. We specifically report on five distinct problem areas, as well as provide suggestions for how to address these problems

THE IMPACT OF EMPLOYEE COMPETENCE ON ORGANIZATIONAL AGILITY: THE MEDIATING ROLE OF IT ALIGNMENT

Scholars have proposed that IT enables organizational agility by extending the reach and richness of firm knowledge and processes. However, this relationship is still open to debate. Based on the dynamic capabilities perspective, this paper proposes a model to investigate how employee competence (i.e., IT competence of business people and business competence of IT professionals) affects organizational agility through IT alignment. Data analysis results show that IT alignment fully mediates the influence of IT competence of business people and partially mediates the influence of business competence of IT professionals on organizational agility. In addition, the two kinds of competence are also positively interacting with each other to enhance IT alignment. We summarize with implications and suggestions for future research

THE CHARACTERISTICS OF FEMALE SOCCER KICKING REVEALED BY 3D KINEMATICS AND ELECTROMYOGRAPHY

Soccer is the mosl popular sport in the world' and rapidly becoming one of the most popular sports in North America. Despite its popularity, little research has been done to facilitate the rapid demand of quantitative findings. Even less attention is being paid to the fact that females now make up almost half the players worldwide. This study initiates a research on female soccer kicking using state-of-the-art technology. The high-tech unit consists of a 3D motion capture system with 9 high-speed cameras (120 Hz) and wireless electromyography (EMG) collection. The results revealed that a) Elite subjects combined the f1exion and extension of the hip, knee and ankle joint to perform the kick while novice subjects primarily used the knee to generate momentum; b) elite group showed a significant higher EMG intensity

SECONDARY CRISIS COMMUNICATION ON SOCIAL MEDIA: THE ROLE OF CORPORATE RESPONSE AND SOCIAL INFLUENCE IN PRODUCT-HARM CRISIS

Because of a large number of customers using social media, firms have embraced social media as a useful communication tool during product-harm crises. However, current knowledge on the relationships between corporate crisis response, customer secondary crisis communication, and customer purchase intention remains limited. Based on an economic view, this study proposes a model to examine how corporate crisis response affects customer secondary crisis communication and finally influence purchase intention in social media context. In addition to the direct effects, this study investigates the moderating effect of social influence in the above relationships based on social influence theory. The empirical results show that corporate crisis response could decrease customer secondary crisis communication, thus lessening the negative impact on customer purchase intention in the social media context. The findings further confirm the moderating role of customers’ perceived social influence in the above relationships. We conclude with implications and suggestions for future research

Multi-Plant Production and Transportation Planning Based on Data Envelopment Analysis

This paper proposes a methodology for developing a coordinated aggregate production plan for manufacturers producing multiple products at multiple plants simultaneously, in a centralized environment via data envelopment analysis (DEA). Based on demand forecast of the planning horizon, the central decision maker (DM) specifies the optimal combination of input resources required by the optimal output targets for each plant to keep the supply and demand in balance, and the accompanying transportation trips and volumes among distribution centers (DCs) or warehouse facilities. In this paper, we focus on an integrated production-transportation problem since production and transportation are two fundamental ingredients in the whole operation chain. We deal with multiple products manufactured in multiple plants.The proposed mixed integer DEA models minimize both production costs and transportation costs. The capacity constraint for each plant is enforced by using the production possibility set theory. Finally, we validate our models by a numerical example and sensitivity analysis