Peter Kropf

Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks.

PURPOSE Since most previous reports of EMG activation profiles from psoas and the abdominal wall have been qualitative, the objective of this work was to document myoelectric activity from these deep muscles. This knowledge is required to assist in choosing specific training exercises and for making rehabilitation decisions that require knowledge of normalized and calibrated muscle activation levels in different tasks. METHODS Intramuscular EMG was collected from five men and three women, in whom amplitudes were normalized to maximum contraction efforts and reported over a wide variety of clinical and rehabilitation tasks. Electrodes were inserted into vertebral portions of psoas and the three layers of the abdominal wall. Normalized signal amplitudes were reported as peak levels and time histories. RESULTS All forms of sit-ups activated psoas (15-35% MVC) more than the curl-up (<10%); psoas was not highly activated during barbell lifting of loads up to 100 kg (< 16% MVC); psoas was most active during maximal hip flexion efforts; push-ups activated psoas up to 25% MVC. Several isometric abdominal exercises were evaluated using the criteria of maximizing abdominal activation while minimizing psoas activity: the side (bridge) support exercise proved the best training method for the abdominal wall. CONCLUSIONS Consideration of deep muscle activity, provided in this report, is important for choosing the most appropriate rehabilitation and training program for an individual. Specific guidance is provided for choosing the best abdominal exercise, together with activation profiles during lifting, during twisting, and during hip rotation.

Appropriately placed surface EMG electrodes reflect deep muscle activity (psoas, quadratus lumborum, abdominal wall) in the lumbar spine.

This study tested the possibility of obtaining the activity of deeper muscles in the torso-specifically psoas, quadratus lumborum, external oblique, internal oblique and transverse abdominis, using surface myoelectric electrodes. It was hypothesized that: (1) surface electrodes adequately represent the amplitude of deep muscles (specifically psoas, quadratus lumborum, external oblique, internal oblique, transverse abdominis); (2) a single surface electrode location would best represent the activation profiles of each deep muscle over a broad variety of tasks. We assumed that prediction of activation within 10% of maximum voluntary contraction (RMS difference between the surface and intramuscular channels), over the time history of the signal, was reasonable and acceptable to assist clinical interpretation of muscle activation amplitude, and ultimately for modeled estimates of muscle force. Surface electrodes were applied and intramuscular electrodes were inserted on the left side of the body in five men and three women who then performed a wide variety of flexor tasks (bent knee and straight leg situps and leg raises, curl ups), extensor tasks (including lifting barbells up to 70 kg), lateral bending tasks (standing lateral bend and horizontal lying side support), twisting tasks (standing and sitting), and internal/external hip rotation. Using the criteria of RMS difference and the coefficient of determination (R2) to compare surface with intramuscular myoelectric signals, the results indicated that selected surface electrodes adequately represent the amplitude of deep muscles-always within 15% RMS difference, or less with the exception of psoas where differences up to 20% were observed but only in certain maximum voluntary contraction efforts. It appears reasonable for spine modelers, and particularly clinicians, to assume well selected surface electrode locations provide a representation of these deeper muscles-as long as they recognize the magnitude of error for their particular application.

A guided cooperative search for the vehicle routing problem with time windows

We have developed a pattern-identification mechanism that endows cooperative search with capabilities to create new information and guide the global search. The proposed mechanism sends information to independent metaheuristics about promising and unpromising patterns in the solution space. By fixing or prohibiting specific solution attribute values in certain search metaheuristics, we can focus the search on desired regions. The mechanism thus enforces better coordination between individual methods and controls the global searchs diversification and intensification. An enhanced cooperative-search mechanism creates new information from exchanged solutions and guides the global search with a pattern-identification mechanism.

A Workflow-Oriented System Architecture for the Management of Container Transportation

In this paper, we introduce a workflow-oriented system architecture for the processing of client requests (CRs) for container transportation. In the context of multi-transfer container transportation, the processing of CRs can be achieved by specific sequences of interdependent activities. These sequences need to be just-in-time created. They also need to be adapted to deal with unexpected events that may occur. Workflow technology is used to model and to manage the processing of CRs. The creation and the adaptation of activity sequences require first, an optimized scheduling of a limited number of resources (by also respecting CRs constraints); and second, a number of special workflow concepts and functionality to correctly manage activity sequences. Optimization models are involved to take care of the resource management and of the activity scheduling. Enhancements of workflow concepts and functionality for workflow management systems are investigated to deal with an activity sequence creation and adaptation. Finally, the proposed architecture includes a rule processing part to reduce the time-consuming manual interaction with the system.

Management Technologies for E-Commerce and E-Business Applications

Keynote Speakers.- More Research Is Indeed Needed in E-commerce Where Were Business Academicians When We Needed Them?.- Cool to Critical: Managing Web Services Now.- Panel Session.- Enforcing QoS: Myth or Reality?.- Managing Quality of Service.- Modeling of Service-Level Agreements for Composed Services.- The Architecture of NG-MON: A Passive Network Monitoring System for High-Speed IP Networks1.- Automated SLA Monitoring for Web Services.- Optimizing Quality of Service Using Fuzzy Control.- Measuring Qualit of Service.- Interaction Translation Methods for XML/SNMP Gateway.- Measuring Application Response Times with the CIM Metrics Model.- Quality Aspects in IT Service Management.- Service Architectures.- Replication and Notification Management in a Knowledge Delivery Network.- Delivering Service Adaptation with 3G Technology.- Remote Code Browsing, a Network Based Computation Utility.- Policy and Process.- Performance Study of COPS over TLS and IPsec Secure Session.- A Criteria Catalog Based Methodology for Analyzing Service Management Processes.- A Comparative Study of Policy Specification Languages for Secure Distributed Applications.- Fault Analysis.- Two Dimensional Time-Series for Anomaly Detection and Regulation in Adaptive Systems.- A Hot-Failover State Machine for Gateway Services and Its Application to a Linux Firewall.- Distributed Fault Localization in Hierarchically Routed Networks.

The GIPSY Architecture

Intensional Programming involves the programming of expressions placed in an inherent multidimensional context space. It is an emerging and highly dynamic domain of general application. The fast growing computer connectivity allows for more and more efficient implementation of distributed applications. The paradigm of intensionality inherently includes notions of parallelism at different levels. However, the currently available intensional programming software tools are becoming obsolete and do not enable us to further push forward practical investigations on the subject. Experience shows that the theoretical advancement of the field has come to acceptable maturity. Consequently, new powerful tools for intensional programming are required. In this paper, we present the design of a General Intensional Programming System (GIPSY). The design and implementation of the GIPSY reflect three main goals: generality, adaptability and efficiency.

Adaptive Load Balancing for DHT Lookups

In the past few years, several DHT-based abstractions for peer-to-peer systems have been proposed. The main characteristic is to associate nodes (peers) with objects (keys) and to construct distributed routing structures to support efficient location. These approaches partially consider the load problem by balancing storage of objects without, however, considering lookup traffic. In this paper we present an analysis of structured peer-to-peer systems taking into consideration Zipf-like requests distribution. Based on our analysis, we propose a novel approach for load balancing taking into account object popularity. It is based on dynamic routing table reorganization in order to balance the routing load and on caching objects to balance the request load. We can therefore significantly improve the load balancing of traffic in these systems, and consequently their scalability and performance. Results from experimental evaluation demonstrate the effectiveness of our approach.

Distributed lookup in structured peer-to-peer ad-hoc networks

Various peer-to-peer (P2P) architectures for ad-hoc networks have been proposed over the last few years Most of them are unstructured and use some form of flooding to locate content, because the physical constraints of the underlying network make the construction of arbitrary application-layer overlays impractical. In this paper, we study the problem of applying distributed hash tables (DHT) to ad-hoc networks Our approach to efficiently lookup content in such networks exploits physical proximity of peers when establishing and maintaining the DHT based routing tables The efficiency of our method is demonstrated by simulation of large networks.

A fast distributed mapping algorithm

Generating an efficient program for a parallel computer requires that the distribution of the processes on the processors comprising the parallel computer is most optimal. This paper presents a new method for a load balanced and communication optimized process distribution onto an arbitrary processor (network) topology. As opposed to many other approaches for this problem, the presented algorithm is fully distributed and based on a purely local method. It has shown to be much faster compared to the classical methods like simulated annealing, heuristic search, etc.

Dynamic Load Sharing in Peer-to-Peer Systems: When Some Peers Are More Equal than Others

Object caching and replication are the primary mechanisms for addressing load balancing in peer-to-peer systems. In structured P2P networks, object popularity is an important challenge because it can adversely impact both the request and forwarding loads in the network. To balance loads across P2P networks, the authors propose a method for dynamically updating routing tables to balance the load induced by forwarding traffic in the neighborhood of nodes holding popular objects.