Do ergonomically designed school workstations decrease musculoskeletal symptoms in children? A 26-month prospective follow-up study

Workstations at school are among several factors that contribute to musculoskeletal symptoms among school-aged children. The aim of this study was to investigate the effects of ergonomically designed workstations on schoolchildren's musculoskeletal symptoms as compared to conventional workstations. In the first 14-month phase of the study (2002-2003, two schools), 42 from the intervention and 46 from the control school participated. In the total follow-up of 26 months (2002-2004), 23 in the intervention group and 20 in the control group participated. Anthropometrics and musculoskeletal symptoms were measured. In general, the ergonomically designed school workstations did not decrease present neck-shoulder, upper back, low back and lower limbs strain and pain, compared to conventional ones during follow-ups.     

Control of posture during tasks representing common work-related postures – a reliability study

Assessment of control of posture using a task battery that represents work-related postural conditions is highly recommended for providing a comprehensive understanding of collective postural demands. However, dearth of evidence exists on the reliability of a task battery, thus precluding its use as an outcome measure in field research. This study investigated the intrasession reliability and systematic variation of force plate derived centre of pressure (COP) measures obtained during repeated performance of a task battery (lifting task, limits of stability and bipedal and unipedal stance). COP signals obtained during each task performance were processed to derive various time-domain COP measures. Statistical analyses revealed that 13 of the 19 COP measures displayed excellent relative (ICC_(2,3) ≥ 0.75) and acceptable absolute reliability (SEM%: ≤ 10). Although COP measures displayed systematic variation, the differences were less or equal to the measurement error, except COP measures of unipedal stance and limits of stability. The chosen task battery is reliable and can be used for comprehensive evaluation of control of posture, in both field and laboratory research.

Practitioner Summary: Repeated evaluation of multiple tasks together sequentially could introduce measurement variability. This study investigated intrasession reliability of a task battery representing common work-related postures. The chosen task battery was found to be reliable with acceptable measurement error and can be used in field research settings for evaluation of control of posture.     

GEDMod – Towards a generic toolkit for emergency department modeling

The design of generic models, or generic building blocks, for health care operations has been discussed in depth and identified as one of the grand challenges for researchers in the field of Modeling and Simulation. In this paper we provide an investigative basis for answering recently raised research questions for a specific sub-domain of health care facilities and a specific Modeling and Simulation paradigm, i.e. Discrete Event Simulation Models of Emergency Departments. We perform a detailed analysis of a large set of published Emergency Department models. This analysis is executed following a structured conceptual modeling framework to ensure the coverage of key conceptual modeling aspects: objectives; input scenarios; output definitions, i.e. commonly used performance indicators; structural components such as physical resources and human resources (including expertise and skill levels); patient classifications (arrival modes, triage grades, complaint categories); patient pathways including triage, treatment (which possibly includes resuscitation or special care) and admission phases; and organizational structures including control policies. The resulting collection and classification of modeling archetypes are used as the basis for an initial generic modeling toolkit for Emergency Department operations. Thereby, the modeler is guided through the main steps of conceptual modeling of Emergency Departments and generic building blocks for each step are provided. The paper concludes with a discussion on the applicability and benefits of the resulting GEDMod framework along with the potential to combine the toolkit into a single generic Emergency Department model.     

Defining limits to multiple and simultaneous anthropogenic stressors in a lake ecosystem – Lake Kinneret as a case study

In this study we expanded a recently developed approach for defining acceptable levels of management policy that will allow sustainable management of water quality in a lake ecosystem. A three dimensional solution space was created to define all acceptable scenarios of N loads, P loads and lake water level (WL) thus providing an integrated tool for defining the extent of measures that will allow lake ecosystem sustainability. The approach included use of a lake ecosystem model, a quantitative system of composite water quality indices (CWQIs) and defined sustainability criteria for the ecosystem. The approach was tested on the Lake Kinneret (Sea of Galilee) ecosystem and succeeded in defining the range of acceptable management policy through the use of long term simulations of different scenarios. Using the results of the scenarios, a number of polygons were created, defined as relative solution domain area (RSDA), which denote the permissible ranges of nutrient loads at different water levels. The polygon, and hence RSDA, boundaries represent critical values of nutrient loads allowing conservation of the lake water quality at each WL. By integrating all RSDA, a three dimensional solution space was created which defines all acceptable ranges of N loads, P loads and WL thus providing lake managers with an integrated tool for defining the extent of measures that will allow sustainability of the lake ecosystem. This novel approach is unique, and presents an example of implementation of a management tool that integrates an ecosystem model, multiple stressors and quantified water quality indices to determine limits of management actions. This approach may well be implemented to other lakes around the world suffering from water quality deterioration as a result of changes in water level and nutrients loads.     

Equal task,equal exposure? Are men and women with the same tasks equally exposed to awkward working postures?

The aim of the study was to determine whether men and woman with equal tasks perform these tasks in the same way. Video recordings of 37 male and 43 female workers in six task groups were observed, from which data regarding frequency and duration of exposure to awkward postures were derived. These data were also compared to self-reported exposures. The results showed that when level, duration and frequency of exposure were analysed at the same time, men and women had slightly different exposure patterns. However, these differences were not found when duration and frequency were analysed separately. From the questionnaires it appeared that men and women generally report similar exposures, but they seemed to over-report their exposure compared to the observed exposures. It is concluded that gender differences in exposure to awkward postures within the same task were small at most and cannot explain the female excess in musculoskeletal symptoms.     

Towards understanding the relationship between team climate and software quality—a quasi-experimental study

This paper describes an empirical study that examined the work climate within software development teams. The question was whether the team climate in software developer teams has any relation to software product quality. We define team climate as the shared perceptions of the team’s work procedures and practices. The team climate factors examined were West and Anderson’s participative safety, support for innovation, team vision and task orientation. These four factors were measured before the project using the Team Selection Inventory (TSI) test to establish subject climate preferences, as well as during and after the project using the Team Climate Inventory (TCI) test, which establishes the subject’s perceptions of the climate. In this quasi-experimental study, data were collected from a sample of 35 three-member developer teams in an academic setting. These teams were formed at random and their members were blind to the quasi-experimental conditions and hypotheses. All teams used an adaptation of extreme programming (XP) to the students’ environment to develop the same software system. We found that high team vision preferences and high participative safety perceptions of the team were significantly related to better software. Additionally, the results show that there is a positive relationship between the categorization of better than preferred, as preferred and worse than preferred climate and software quality for two of the teamwork climate factors: participative safety and team vision. So it seems important to track team climate in an organization and team as one (of many) indicators of the quality of the software to be delivered.

A fuzzy PLC with gain-scheduling control resolution for a thermal process – a case study

This paper presents a case study on the practical implementation of a fuzzy-PLC system for a thermal process. The theoretical study indicates that the inferior performance of fuzzy-controlled processes around a reference point is often caused by insufficient resolution of the fuzzy inference. The limitations of ladder logic cannot support complex algorithms for resolution improvement. A simple gain adaptation method is presented here, to achieve smooth fuzzy control, that can be easily implemented in a PLC system. Real-time experiments on an unidentified thermal process show the effectiveness of the approach, as well as the robustness of the fuzzy controller with respect to the time-varying features of the process.     

Towards designing a green data center farm for Internet services: Iran’s case study

Energy consumption has become a critical design factor in today’s data centers. In recent years, extensive research has been done to address power–performance trade-off in data centers considering both IT equipments and cooling infrastructures (e.g., thermal-aware task scheduling, server consolidation, load balancing and geographical load balancing to name a few). This paper introduces a design-time technique that targets energy-efficient design of a green data center farm in Iran. Workload predictions, geographical maps of wind speed and solar radiation, data center and renewable resources configurations are used as a priori to design an energy-efficient data center farm for Internet services. The proposed problem is mathematically formulated as a nonlinear optimization problem and is effectively solved using a coordinate descent-based method. We also show that with some minor modification, our proposed technique can be applied at run-time for the purpose of change management. The experimental results show that the proposed method can lead to 11.6 % cost saving on average over conventional approaches.     

A study of performance and scalability metrics of a SIP proxy server – a practical approach

In recent years, Internet Protocol (IP) telephony has been a real alternative to the traditional Public Switched Telephone Networks (PSTN). IP telephony offers more flexibility in the implementation of new features and services. The Session Initiation Protocol (SIP) is becoming a popular signalling protocol for Voice over IP (VoIP) based applications. The SIP proxy server is a software application that provides call routing services by parsing and forwarding all the incoming SIP packets in an IP telephony network. The efficiency of this process can create large scale, highly reliable packet voice networks for service providers and enterprises. We established that the efficient design and implementation of the SIP proxy server architecture can enhance the performance characteristics of a SIP proxy server significantly. Since SIP proxy server performance can be characterised by its transaction states of each SIP session, we emulated the $M/M/1$ performance model of the SIP proxy server and studied some of the key performance benchmarks such as average response time to process the SIP calls, and mean number of SIP calls in the system. We showed its limitations, and then studied an alternative $M/M/c$ based SIP proxy server performance model with enhanced performance model and studied additional key performance characteristics such as server utilisation, queue size and memory utilisation. Provided the comparative results between the predicted results with the experimental results conducted in a lab environment.     

MORE – a multimodal observation and analysis system for social interaction research

The MORE system is designed for observation and machine-aided analysis of social interaction in real life situations, such as classroom teaching scenarios and business meetings. The system utilizes a multichannel approach to collect data whereby multiple streams of data in a number of different modalities are obtained from each situation. Typically the system collects a 360-degree video and audio feed from multiple microphones set up in the space. The system includes an advanced server backend component that is capable of performing video processing, feature extraction and archiving operations on behalf of the user. The feature extraction services form a key part of the system and rely on advanced signal analysis techniques, such as speech processing, motion activity detection and facial expression recognition in order to speed up the analysis of large data sets. The provided web interface weaves the multiple streams of information together, utilizes the extracted features as metadata on the audio and video data and lets the user dive into analyzing the recorded events. The objective of the system is to facilitate easy navigation of multimodal data and enable the analysis of the recorded situations for the purposes of, for example, behavioral studies, teacher training and business development. A further unique feature of the system is its low setup overhead and high portability as the lightest MORE setup only requires a laptop computer and the selected set of sensors on site.     

A comparison study for displacement computation – Horn and Shunck's method versus March's method

The aim of this study is to reveal the effectiveness of a displacement computation method proposed by March in 1988. In common with a method proposed by Horn and Shunck in 1981, March's method also utilizes the measure of the departure from smoothness in the computed displacement as a regularization term. However, these two method have a difference in the definition of the correspondence error between images. Horn and Shunck eliminated the second and higher order terms of spatial brightness variation, so that the correspondence error is defined as a linear model. On the other hand, March defined a non-linear model in which the second and higher order terms are preserved. In order to verify the difference between two methods experimentally, we compare two methods with simulation images. Consequently, it is shown that March's method gives more accurate displacement for non-linearity in the brightness variation and less computation cost.     

Forearm muscle hemodynamic responses in healthy men during a seven-hour exposure to repetitive ulnar deviation task – A psychophysiological study

The purpose was to evaluate vascular hemodynamics in the forearm of fourteen healthy men over a seven-hour workday of repetitive work at and above their acceptable workload. Participants performed an ulnar deviation task at a frequency of 15 repetitions per minute for seven hours: at their psychophysically chosen acceptable torque (day 1), and at 25% above the acceptable torque (day 2). Hemodynamic responses (Tissue oxygenation index [TOI] and Tissue Hemoglobin Index [THI]) from the carpi ulnaris flexor and extensor muscle regions of the right hand were collected for the last 5 min of every hour of task performance.     

\mathcal{C}oo\mathcal{PS} – Towards a method for coordinating personalized services

This paper presents oo which is a method for oordinating ersonalized Services. These services are primarily offered to mobile users. The concept of services is the object of intense investigations from both academia and industry. However, very little has been accomplished so far regarding first, personalizing services for the benefit of mobile users, and second, providing the appropriate methodological support for those (i.e., designers) who will be specifying the operations of personalization. Various obstacles still exist such as lack of techniques for modeling and specifying the integration of personalization into services, and existing approaches for service composition typically facilitate orchestration only, while neglecting contexts of users and services. ooconsists of several steps ranging from service definition and personalization to service deployment. Each step has some representation techniques, which aim at facilitating the specification and validation of the operations of coordinating personalized services. Zakaria Maamar is an associate professor in computer sciences at Zayed University, Dubai, United Arab Emirates. His research interests include Web services, software agents, and context-aware computing. Maamar has a PhD in computer sciences from Laval University. Djamal Benslimane is a full professor in computer sciences at Claude Bernard Lyon 1 University and a member of the Laboratoire d'InfoRmatique en Images et Systèmes d'information- Centre National De la Recherche Scientifique (LIRIS-CNRS), both in Lyon, France. His research interests include interoperability, Web services, and ontologies. Benslimane has a PhD in computer sciences from Blaise Pascal University. Michael Mrissa is a Ph.D. candidate in computer sciences at Claude Bernard Lyon 1 University and a member of the Laboratoire d'InfoRmatique en Images et Systèmes d'information - Centre National De la Recherche Scientifique (LIRIS-CNRS), both in Lyon, France. His research interests include semantic Web services, interoperability and peer-to-peer networks. Chirine Ghedira is an associate professor in computer sciences at Claude Bernard Lyon 1 University and a member of the Laboratoire d'InfoRmatique en Images et Systèmes d'information- Centre National De la Recherche Scientifique (LIRIS-CNRS), both in Lyon, France. Her research interests include Web services and context-aware computing. Ghedira has a PhD in computer sciences from the National Institute for Applied Sciences (INSA).     

Constrained Bayesian state estimation – A comparative study and a new particle filter based approach

This paper investigates constrained Bayesian state estimation problems by using a Particle Filter (PF) approach. Constrained systems with nonlinear model and non-Gaussian uncertainty are commonly encountered in practice. However, most of the existing Bayesian methods are unable to take constraints into account and require some simplifications. In this paper, a novel constrained PF algorithm based on acceptance/rejection and optimization strategies is proposed. The proposed method retains the ability of PF in nonlinear and non-Gaussian state estimation, while take advantage of optimization techniques in constraints handling. The performance of the proposed method is compared with other accepted Bayesian estimators. Extensive simulation results from three examples show the efficacy of the proposed method in constraints handling and its robustness against poor prior information.     

Compliance management ontology – a shared conceptualization for research and practice in compliance management

The diversity of stakeholders in compliance management initiatives contributes to the challenges organisations face when managing compliance, and consequently adds to the cost of compliance. In particular, there is evidence that the lack of a common or shared understanding of compliance management concepts is a barrier to effective compliance management practice. Taking an information-centric view to addressing this challenge, this paper reports on the development of an ontology intended to provide a shared conceptualisation of the compliance management domain for various stakeholders. The ontology is based on input from domain experts and practitioners, validated and refined through eight case studies, and subsequently evaluated for its usability in practice.     

QSIA – a Web-based environment for learning,assessing and knowledge sharing in communities

This paper describes a Web-based and distributed system named QSIA that serves as an environment for learning, assessing and knowledge sharing. QSIA – Questions Sharing and Interactive Assignments – offers a unified infrastructure for developing, collecting, managing and sharing of knowledge items. QSIA enhances collaboration in authoring via online recommendations and generates communities of teachers and learners. At the same time, QSIA fosters individual learning and might promote high-order thinking skills among its users. QSIA's community, conceptual architecture, structure overview and implementations are discussed.     

DMTO – a method for Discrete Material and Thickness Optimization of laminated composite structures

This paper presents a gradient based topology optimization method for Discrete Material and Thickness Optimization of laminated composite structures, labelled the DMTO method. The capabilities of the proposed method are demonstrated on mass minimization, subject to constraints on the structural criteria; buckling load factors, eigenfrequencies, and limited displacements. Furthermore, common design guidelines or rules, referred to as manufacturing constraints, are included explicitly in the optimization problem as series of linear inequalities. The material selection and thickness variation are optimized simultaneously through interpolation functions with penalization. Numerical results for several parameterizations of a finite element model of a generic main spar from a wind turbine blade are presented. The different parameterizations represent different levels of complexity with respect to manufacturability. The results will thus give insight into the relation between potential weight saving and design complexity. The results show that the DMTO method is capable of solving the problems robustly with only few intermediate valued design variables.     

Fourier and wavelet descriptors for shape recognition using neural networks—a comparative study

This paper presents the application of three different types of neural networks to the 2-D pattern recognition on the basis of its shape. They include the multilayer perceptron (MLP), Kohonen self-organizing network and hybrid structure composed of the self-organizing layer and the MLP subnetwork connected in cascade. The recognition is based on the features extracted from the Fourier and wavelet transformations of the data, describing the shape of the pattern. Application of different neural network structures associated with different preprocessing of the data results in different accuracy of recognition and classification. The numerical experiments performed for the recognition of simulated shapes of the airplanes have shown the superiority of the wavelet preprocessing associated with the self-organizing neural network structure. The integration of the individual classifiers based on the weighted summation of the signals from the neural networks has been proposed and checked in numerical experiments.