Group exercise is more effective for gaining motivation than exercising alone, but it can be difficult to always find such partners. In this paper, we explore the experiences that joggers have with a virtual partner instead of a human partner and report on the results of two controlled experiments evaluating our approach. In Study 1, we investigated how participants felt and how their behav-ior changed when they jogged indoors with a human partner or with a virtual partner compared to solitary jogging. The virtual partner was represented either as a full-body, limb-only, or a point-light avatar displayed on smartglasses. In Study 2, we investigated the differences between the three representations as virtual partners for casual joggers in an outdoor setting. Based on our results, we propose implications for the design of virtual runners as casual jogging partners and speculate on their relationship with human users.

Augmented reality (AR) optical-see-through (OST) head-mounted displays (HMD) have developed to a point where browsing information on the go is possible. In this paper, we investigate the readability of text on an AR HMD while the user is walking. There are two common methods of displaying text on a HMD: anchoring the text on the screen coordinate system or the world coordinate system. We report on the results of two laboratory experiments comparing text readability when the text is displayed in these two coordinate systems, and while the participants walked on a treadmill. In the first experiment, the participants read letter strings comprising Sloane letters, whereas the second experiment used English words. In addition to evaluating the text readability and workload experienced by participants, we employed IMU sensors to compare the effects of the text display method on the participants' head movement and gait. In both experiments, the reading speed and head movement were significantly higher and mental workload significantly lower for the world coordinate system than for the screen coordinate system. These results suggest that text readability while walking is better on the world coordinate system, and displaying text with the screen coordinate system results in an unnatural gait owing to the user trying to keep their head still in an effort to stabilize the HMD screen.

The development of ambient assisted living environments requires the growth of the associated technologies of the inside devices. In this article, we propose the Intellevator, an intelligent elevator system in smart buildings that could pro-actively provide passengers assistive information based on the real-time context sensing and awareness. We firstly introduce the embedded sensing approach to upgrade a conventional elevator to become Internet of Things-enabled. Then, after transferring and increasing the computational capability to the agent server, we prototyped an end-user centered application that provides the real-time context visualization and intelligence for assisting users, such as the advices of riding at other floor for reducing passengers' waiting time. We experimented this proposal by integrating with a real conventional elevator and conducted a 22-participants attended case study for evaluation. The results demonstrated that the system usability and user experience of the Intellevator is beyond that of the existing conventional elevator. Furthermore, valuable feedbacks for advice making and context visualization have been collected; they will serve as an informed reference for developing the future elevator system.

We present a novel assistive method for leading casual joggers by showing a virtual runner on see-through head-mounted display they worn. It moves at a constant pace specified in advance by them, and its motion synchronizes the user's one. People can always visually check the pace by looking at it as a personal pacemaker. They are also motivated to keep running by regarding it as a jogging companion. Moreover, proposed method overcomes safety problem of AR apps. Its most body parts are transparent so that it doesn't obstruct their view. This study, thus, may contribute to augment daily jogging experience.

SONET/SDH is historically the dominant telecom transport infrastructure for backbone networks, and it is optimized for reliable delivery of voice and private-line services. Efficient utilization of the existing infrastructure through novel methods and algorithms can lead to higher revenue, which is attractive for network operators. In this study, we examine a network of inter-connected SONET/SDH rings that use dual-node interconnection employing the drop-and-continue facility, which is the de-facto standard for interworking SONET/SDH protection architectures. We develop an efficient algorithm for provisioning in such a network while keeping fragmentation of capacity low and taking into account the various constraints imposed by the underlying physical layer. We examine the case of dual-node-interconnected ring networks employing both contiguous and virtual concatenation (a next-generation SONET/SDH architecture), and as expected, we discover that provisioning higher-bandwidth connections with virtual concatenation offers significant improvement. The stringent time-slot alignment and contiguity constraints imposed by contiguous concatenation are further compounded by the constraints imposed by the ring interworking architecture, and virtual concatenation allows capacity to be used more efficiently.

P2P applications are among the most popular Internet applications and constitute a majority of Internet traffic today. From the perspective of network management, a thorough understanding of the stochastic properties of P2P traffic is thus crucial to designing better traffic/resource control algorithms. However, previous work on measuring and analyzing P2P traffic focuses either on a specific type of P2P applications or report only qualitative or quantitative findings in the measured traffic, without systematically analyzing and modeling P2P traffic. In this paper, we aim to bridge the gap and perform a detailed analysis and modeling of P2P traffic of different types. We first gather and identify P2P traffic on a trans-pacific link between Japan and US. Then based on the flow level (transport layer) information, we analyze and model the marginal distributions of the traffic volume, connection duration, and connection interarrival times for P2P connections of Napster, BitTorrent (BT), eDonkey, Gnutella, and Fasttrack, respectively. We also study the burstiness property of P2P traffic generated by these five different applications and the implication/impact of connections with zero traffic volumes. A major finding of our study is that due to the different parameters/strategies used in the file sharing mechanism, P2P traffic of different applications exhibits different traffic characteristics. As a result, the traffic metrics of interest (i.e., the per-connection traffic volume, the connection duration, and the connection interarrival times) cannot be characterized uniformly with a single model among the different types of applications, but instead have to be modeled with different probability distributions.

Push-to-talk over cellular (PoC) is considered as one of important applications in next generation networks (NGN). The main objective of this study is to investigate the performance of our PoC system evaluated over three operational 3G networks in the US. Measurements are conducted in two stages. First, several generic measurements such as round trip time (RTT), UDP, TCP, and dormant mode are made to understand the fundamental characteristics of 3G packet switched (PS) networks for the voice and data transmissions of the PoC service. Next, various parameters and features in our PoC software are tested to evaluate the performance of startup latency, voice latency, and voice quality. In conclusion, through empirical study we have shown that PoC applications can achieve high quality in current 3G PS networks. Furthermore from these results we study the network requirements to be solved in NGN for the voice and data communications.

Modeling and analysis of wireless traffic is fundamental to traffic engineering and resource management. The majority of existing work in this arena has focused on modeling/analyzing aggregate traffic, and little has been done in modeling/analyzing wireless traffic at the per-user level. In this paper, we bridge the gap and perform a detailed analysis and modeling on the traffic generated by individual wireless users, leveraging the data traces collected in a period of 4 months (November 2003 - February 2004) on the Dartmouth campus-wide 802.11 WLANs.Our study indicates that several parameters that characterize the wireless traffic generated by individual users are predictable, such as the traffic volume originating from a user and destined for a specific IP address, the set of destination IP addresses (for which connections initiated by a user are destined), and the patterns by which a wireless user connects to applications. We also model the per-connection traffic volume, the duration, and the interarrival time, of connections issued by a user using Weibull or Pareto distributions, and show that the burstiness of aggregate wireless traffic (which has been reported in the literature) is a direct consequence of the burstiness of the burstiness of traffic generated by individual users. These findings can be used to optimize traffic and resource management and provide better QoS (in terms of availability, resiliency, and performance).

Optical Burst Transport network is a novel WDM ring architecture for Metropolitan Area Networks (MAN). It leverages the advantages of optical burst switching and WDM rings, while using a token-based medium access scheme. In this paper, we investigate protection together with spatial reuse property. Specifically we show how protection in OBT can be different from conventional protection and propose three algorithms for implementing a fast and low implementation cost, unidirectional 1:1 protection scheme. We analyzed the performance of these schemes via simulation and found an optimum algorithm for minimizing data loss and maximizing data delivery during the fault.

This paper revisits the concept of bandwidth on demand. In the late 1990's, the promise of instant bandwidth availability led to the development of market mechanisms that companies used to trade bandwidth just as other commodities. Those trading markets all but disappeared with the bursting of the telecom bubble in March 2001. Several years after its demise, it is useful to look at the concept of bandwidth trading anew in considering the development of telecommunications in the information age. The paper offers evidence that bandwidth trading is technically feasible, improves network efficiencies and generates a good return on investment (ROI) for both carrier and operator, which translates into added service offerings for the end-customer. The paper focuses on three main issues of relevance to trading markets: network economics, regulation and technical issues. The paper conducts an introspective study of the economics of the telecommunication network and the drivers for bandwidth markets. It then discusses US regulatory issues including the proposed Telecom bill of 2005, as an amendment to the Telecom Act of 1996 and its effect on competition and the telecom environment. It goes to consider technology-related issues including new advances in control plane and data networking technology and finally combinatorial auctions and futures markets on the business side. In this paper, we take an introspective look at bandwidth trading markets. We first introduce bandwidth trading markets and their advantage versus long-term leasing contracts. The business transaction conducted between a carrier that owns the infrastructure and the service provider that builds the data network topology can be a contract negotiated over a period of time with a strict service level agreement (SLA), but also a rapid leasing transaction executed through a market the way other commodities -rice, stocks and electricity - are bought and sold. We argue for a renewed interest in bandwidth trading and consider three pillars for modern bandwidth trading that are important for the development of these markets with benefit to all pieces of the telecom ecosystem: established and competitive carriers and service providers, large and startup equipment vendors and end-users, who benefit from lower cost and new innovation

This paper investigates the effectiveness of data gathering protocols for in-body biomedical sensor networks. We studied the performance of representatives from each of three major protocol categories: (1) low energy adaptive clustering hierarchy (LEACH), a cluster-based protocol, (2) power efficient gathering for sensory information systems (PEGASIS), a chain-based protocol, and (3) hybrid indirect transmissions (HIT), a hybrid of chains and clusters. First, the ability of each protocol to perform in-network source separation was judged. We consider a human-machine interaction application in which implanted bio-sensors communicate motor unit actions of human muscles to a remote computer. Motor unit action potentials (MUAPs) were modeled, and source separation and recovery at each sensor was simulated. We compare the performance of HIT and LEACH in terms of signal distortion ratios and the energy costs of fusion and communication. Second, we report on the efficiency of each protocol for in-body data collection, using Gupta et al's propagation loss model for biomedical applications (PMBA) - an accurate model of power loss due to signal absorption by the human body. We investigate the effectiveness of HIT, LEACH, and PEGASIS under this model, and compare their performance in terms of energy efficiency and network lifetime

One major challenge in sensor networks is to maximize network life under the constraint of extremely limited power supply. Thus, an important design issue of routing and data-gathering protocols is minimizing energy. This paper investigates the energy efficiency of two data gathering protocols, based on distributed versions of Shortest Path Tree (SPT) and Maximum Leaf Tree (MLT) algorithms [1]. The two have been extended to be dynamic by applying localized tree-reconstruction mechanism [2] to handle joining and leaving (death) of sensor nodes. Accurate energy consumption has been carefully modeled for both leaf-nodes and intermediate nodes, when sending and receiving data. Performance is evaluated through detailed simulation, including exchange of control messages among sensor nodes. Simulation results have shown that SPT, due to its simplicity and smaller number of control messages, achieves better energy efficiency and less delay in tree constructions, data transmissions, and dynamic tree reconstructions.

We report studies on peer-to-peer (P2P) traffic analysis, modeling, and evaluation of policies for the management P2P traffic in metropolitan networks. We conducted crawler-based measurement and analysis of P2P traffic using Gnutella. Based on the empirical parameters obtained through the measurement, known modeling techniques of P2P peers and contents, and GeoPoint, a geomapping technology, we built a P2P traffic simulator using J-Sim, a Java-based network simulation tool. The simulator is scenario-driven, allowing its user to customize network settings and service environment to examine the behavior of P2P traffic. With the P2P simulator, we were able to recreate a spatio-temporal traffic pattern characteristic to P2P services observed in August 2002. We then evaluated three different P2P traffic management policies, showing that traffic localization using a peer selection policy at super peers is possible, containing P2P traffic to the local metropolitan network as much as 40%.

We present policy-based management, based on the IETF framework, of optical networks having a GMPLS (generalized multiprotocol label switching) based control plane to realize integration of the control and management planes. A business model centered on bandwidth trading is used to demonstrate the need for policy-enabled GMPLS (PE-GMPLS) in the "photonic IP" age.

This paper presents a network node architecture and several traffic management mechanisms that are capable of achieving QoS provisioning for the guaranteed service (GS), the controlled-load (CL) service, and the best-effort (BE) service under IETF integrated services (IntServ) paradigm. Our architecture offers the attractive feature of in-sequence delivery for all packets, albeit some of which may be out-of-profile. Simulation results show that, once admitted into the network, our architecture and traffic management algorithms provide hard performance guarantees to GS flows under all conditions, consistent (or soft) performance to CL flows under both light load and heavy load conditions, and minimal negative impact to in-profile GS, CL and BE traffic should there be any out-of-profile behavior from some flows.

This paper presents an implementation architecture based on per flow queueing that is capable of achieving QoS provisioning for future integrated services networks consisting of the guaranteed service (GS), the controlled-load (CL), and the best-effort (BE) service classes. We propose several novel traffic management mechanisms, including adaptive rate allocation for controlled-load (ARC), a hybrid model-based and measurement-based admission control algorithm for GS and CL flows, and a quasi-pushout plus (QPO+) packet discarding mechanism. Simulation results show that our architecture and algorithms provide hard QoS guarantees to GS flows under all conditions, consistent (soft) QoS to CL flows under both light and heavy load conditions, and effective control of negative impact from non-conforming CL flows. Our architecture and algorithms also resolve several issues associated with the traditional class-based approach.

Policy-based networking (PBN) is gaining a wide acceptance in IP management, resulting in a more unified control and management approach toward complexity of IP management. QoS interworking in IP management based on PBN is going to provide QoS guaranteed/differentiated IP connection services. QoS interworking issues between enterprise network and public IP network are studied. The exponential growth of intranet/Internet interworking itself may put PBN in jeopardy. To counter the increasing management complexity, two approaches, policy abstraction and hierarchy organization with precedence rules are proposed and studied.

Enterprise level QoS issues are discussed, from which QoS evolution paths are derived. Service level QoS issues are identified and they have been studied as apart of service quality issues in TINA service architecture. TINA stream binding and its role in the TINA QoS framework are presented. A soft guarantee of stream quality is proposed, which does not require strict resource reservation. Soft guarantee concept combined with TINA stream binding architecture supports progressive evolution of service quality.

This paper presents a new wire length estimation technique for row-based design. Noting that the local topological structure of the network is often reflected in the local structure of the placement, we present a technique of topological analysis of the network, in which the local structure of the network is characterized by a growing sequence of multilevel neighborhoods. By assuming a pointwise independent branching process, we derive equations for the probability density of multilevel neighborhoods. The wire length distribution is found by solving these equations. For thirteen industrial circuits tested, this technique gives an average of 15.1% estimation accuracy.

An approach toward ath-oriented tirnii -driven place-{ t ment is proposed.We rst transform the p acement with timing constraints to a Lagrange problem, A primal-dual a.ppro~IS USed to find the optimrd relative module locatlons.In each primal dual iteration, the primal problem is solved by a piecewise linear resistive network method, whale the dual process is used to update the Lagrange multiplier.The sparsity of the piecewiee liiear resistive network is exploited to obt airt dramatic improvement on the efficiency of the calculation.Up to 22.o% of clock cycle reduction was observed for Primary2 test case.1

High performance multiprocessing systems have been increasingly using heterogeneous digital signal processors (DSPs) for overall systems gain. Scheduling a DSP algorithm on such a system must address issues of interprocessor communication as well as parallelism extraction for optimal throughput. These issues have been extensively examined for multiprocessor systems incorporating homogeneous processors. A heterogeneous macropipelined scheduling scheme has been described which addresses the aforementioned communication and parallelization issues. The advantage of resorting to a heterogeneous scheme in specific cases is illustrated with examples.>