This work describes a motion-sensing enabled personalized exercise system for cardiac rehabilitation called CAROLS, capable of assisting healthcarers to find evidence-based effective exercise program for individual, and then motivating cardiac outpatients to improve their health recovery throughout a series of effective personalized rehabilitation exercises. In addition to making home-based cardiac rehabilitation exercise more effective and efficient, the CAROLS system can provide an interactive and user-friendly virtual gaming-environment for rehabilitation exercise in terms of monitoring real-time vital signs, increasing outpatient compliance for doctor prescription, as well as evaluating exercise efficiency and patient safety via a fusion function between a motion sensing technology and a wearable sensor device. The experimental system is in service trials with preliminary verification results including heart rate variability (HRV) analyses and motion similarity analysis of the 3-minute step test for normal users. Therefore, in addition to monitoring the exercise intensity and posture accuracy of outpatients, the CAROLS system provides clinical experts with a valuable reference for adjusting the exercise prescription in future scheduled return.

This paper analyzes the trunking performance of ATM Adaptation Layer Type 2 (AAL2) for variable bit rate (VBR) voice transport. In order to transmit voice traffic over ATM networks, unstructured and structured circuit emulation services using AAL1 were proposed as possible standard-based methods. However, although AAL1 is offered as a standard-based solution by some ATM equipment manufacturers, it is not considered an optimum solution, in terms of bandwidth utilization efficiency, for voice transport due to the lack of support of multiple individual voice users per ATM connection, compression, and silence suppression. In order to satisfy the critical need in the market for voice-over-ATM, AAL2 is defined in the ITU-T Recommendation I.363.2 which is designed with the capabilities to support multiple voice users per ATM connection and transport compressed/silence-suppressed VBR voice traffic. In this paper, we conduct detailed quantitative analysis of the trunking performance of AAL2.

The insatiable need for high bandwidth and low latency is spurring research into the next generation of high-speed networks (NGHSN). The design of these NGHSN will be typically motivated by the use of advanced networking technologies. The recent technological advancements in the field of WDM, render WDM-based networks a promising architectural candidate for the future NGHSN. Since ATM have the capacity for providing QoS guarantees, we propose a candidate architecture that combines the two technologies, i.e., ATM and WDM for the NGHSN. Furthermore, we observe that service survivability (i.e., continued service provision in the event of network facility failures) is a very important concern since service disruption at high-speeds can cause a considerable amount of loss. Hence, in this paper, we propose and analyze the performance of a restoration strategy that can tap the advantages of the two technologies to provide network robustness/service survivability.

A prototype software system that implements a methodology for the strategic planning of survivable interoffice networks is presented. The software system determines strategic locations and ring types for synchronous optical network ring placement. Two types of survivable network architectures are considered/spl mdash/1:1 diverse protection and SONET self-healing rings. The software considers three types of SONET self-healing rings/spl mdash/unidirectional, 2-fiber bidirectional, and 4-fiber bidirectional. Hubbing is assumed in all architectures. Inputs include nodes, links, connectivity, facility hierarchy, and multiyear point-to-point demands, together with the costs of fiber material and splicing, route mileage (installation), and multiplexors and regenerators of different rates. The outputs are a set of near-optimal rings based on cost, specifying the ring types and rates, fiber span sizes and counts, regenerator locations and speeds, the topology (set of links to be used), and the network cost. In addition, the software outputs the time in the planning period that each ring and fiber span should be installed.>

The viability of distributed control restoration using digital cross-connect systems (DCS) depends on its capability for restoring services within specified time requirements, and its economics for providing restoration compared to other alternatives. The authors report a Bellcore study for the impact of the DCS architecture on distributed restoration. This study concludes that currently proposed distributed control DCS self-healing schemes may not meet the 2 second restoration objective for large metropolitan local exchange carrier's networks, regardless of the distributed algorithm used, if the present DCS system architecture which uses serial message processing and serial path cross-connection remains unchanged. They also discuss several DCS architecture enhancement options, including a parallel processing/cross-connect DCS architecture, which may improve the service restoration time.>

Provides an overview of the special issue of the IEEE Journal of Communications, Volume 12, Number 1 (January 1994) which addresses open questions in network integrity, reliability and survivability. Current progress in this area is discussed. The questions addressed include user survivability perspectives on standards, planning, and deployment; the analysis and quantification of network disasters; survivable and fault-tolerant network architectures and associated economic analyses; and techniques to handle network restoration as a result of physical damage or failures in software and control systems. Special interests are devoted to the survivability of broadband networks employing the new transport/switching techniques based on the synchronous optical network (SONET) and asynchronous transfer mode (ATM) standards due to their emerging role in future B-ISDN. Network integrity due to failures of common channel signaling (CCS) systems is also very critical. The present special issue includes 22 papers and is organized into the following sections: user perspectives and planning, software quality and reliability, network survivability characterization and standards, network restoration for SONET networks, network restoration for ATM networks, traffic effect and performance enhancement for computer networks, and survivable network design methods. Network restoration methods for SONET, ATM, and computer networks correspond to those for the physical layer (SONET), ATM layer, and the network layer, defined in the CCITT broadband ISDN layer structure.>

A restorable network comprised of a mesh of ATM virtual paths (AVPs) is expected to be superior to distributed SONET digital cross-connect self-healing networks in terms of restoration time. The paper presents a reliable protocol and evaluation of its performance for control information transfer in distributed AVP self-healing networks. Two error-recovery technologies for the data-link level (selective retransmission and go-back-N) in AVP networks are reviewed, and a model for evaluating the delay of the go-back-N method that has been used in existing terrestrial systems is derived analytically. The proposed analytic model is combined with a self-healing simulator for AVP mesh networks to evaluate the restoration time characteristics. Case study results for the worst-case scenario show that the total restoration time, including link-by-link error control for self-healing control messages, is expected to be less than 2 s, which is the time objective for complete restoration for a metropolitan LATA network. The results also show that the estimated average delay penalty for adding the link-by-link error recovery process is 7.5 ms for complete service restoration.>

The self-healing mesh network architecture using digital cross-connect systems (DCSs) is a crucial part of an integrated network restoration system. The conventional DCS self-healing networks using logical channel protection may require a large amount of spare capacity for network components (such as DCSs) and may not restore services fast enough (e.g., within 2 s). The authors propose a passive protected DCS self-healing network (PPDSHN) architecture using a passive protection cross-connect network for network protection. For the PPDSHN architecture, network restoration is performed in the optical domain and is controlled by electronic working DCS systems. Some case studies have suggested that the proposed PPDSHN architecture may restore services within a two-second objective with less equipment cost than the conventional DCS self-healing network architecture in high-demand metropolitan areas for local exchange carrier networks. The proposed PPDSHN architecture may apply to not only the centralized and distributed control DCS network architectures, but also asynchronous, SONET and ATM DCS networks. Transparency of line rates and transmission formats makes the PPDSHN network even more attractive when network evolution is a key concern of network planning.>

A ring architecture that uses the asynchronous transfer mode (ATM) virtual path (VP) concept to reduce the SONET ring cost in terms of bandwidth management is discussed. The add-drop multiplexer (ADM) proposed for VP ring architectures can evolve from existing SONET ADMs by replacing the STS-3 termination cards by the ATM STS-3c line cards. Existing standard self-healing schemes and protocol SONET rings can be applied to proposed ATM/SONET VP rings. A case study based on a BCC (Bellcore client company) ring network and the sensitivity analysis suggests that the proposed ATM VP ring architecture may be a cost-effective option for implementing the distributed ring grooming system at the DS 1 level. The proposed VP self-healing rings are not only used to carry existing DS 1 and DS 3 service, but can also be used to more cost-effectively consolidate switches for public-switched services and for SMDS, frame relay, and FDDI in metropolitan areas.>

A class of SONET-based self-healing ring (SHR) architectures and associated control schemes are reviewed. It is shown that the cost and capacity tradeoffs between bidirectional SHRs (B-SHRs) and unidirectional SHRs (U-SHRs) depend strongly upon the application, the network size and the demand pattern. An analysis of the impact on the SONET standard suggests that using automatic protection switching (APS) schemes with SONET SHR architectures requires a change of currently standardized SONET K1 and K2 overhead byte definitions and functionality. Alternatively, a simple distributed control scheme using path AIS avoids a change of the SONET standard in terms of K1 and K2 operations, and thus can be deployed on a timely basis and may ease intervendor compatibility problems. The selection of appropriate SONET SHR architectures depends upon the operating telephone companies' economic analysis, emphases on multivendor environment, SHR implementation time frame, and standards progress on making the change to support a bidirectional ring architecture.>

The authors describe methods to design cost-effective survivable telecommunications networks that use fiber-optic transmission links. One of these methods utilizes optical switching devices to implement route diversity during cable cuts. These methods have been incorporated into a software tool consisting of three modules: a topology generator, a circuit to DS3 bundler, and a multiplex layout system. This tool is compact enough to run on a personal computer. Each of these three modules is described, and sample results are provided.>

The goals of the class-of-service (COS) routing concept in packet-switched networks are to meet user requirements and to maximize network resource utilization. A statistical analysis model is proposed to analyze network traffic using all recorded data to determine what COSs are present and their associated bandwidth and delay requirements. The UNINET call-record database is used to demonstrate the COS concept. The experimental results show that the traffic patterns defined by COS exist. The bandwidth distribution for 300-b/s call is approximately normal. However, bandwidth distributions for calls equal to or greater than 1200 b/s are exponential, indicating that bandwidth is not a very predictable parameter for these speeds. Lower speeds tend to have a low input bandwidth and slightly higher output bandwidth.>

Several inter-LATA carriers in the United States are implementing fiber optic networks. The geographic coverage of these networks coupled with the bias to choose fiber as backbone links via traditional data network design yields an opportunity for pre-ISDN integration of voice and data. This paper presents three transitional models for pre-ISDN integration of voice and data. The impact of incorporating a fiber optic network in the traditional data design formulation is demonstrated. Based upon the theoretical considerations of fiber optic incorporation, data routing, delay, throughput, and reliability are redefined, yielding an inverse design problem formulation for data. Practical considerations are presented with each transitional model.

The AN/1 network architecture employs compact LANs as integrated switching nodes. The multibussed nodal architecture imposes a natural hierarchy to the network interconnection problem. A nodal interconnection method is introduced as a generalization of hierarchical topology design techniques. Based on traffic and distance, a flat nodal topology is decomposed into several level, overlapped subnetworks. Each subordinate subnetwork communicates with its ordinate subnetwork via two formal gates. The traffic matrix for each subnetwork can be obtained. Linear programming techniques are used to determine bandwidth requirements. Perturbation procedures are applied to determine the appropriate groupings of LANs into subnetworks and the appropriate hierarchy. A flat topology may be returned if it is optimal.